Abstract: Records of bird species observed by F.L. Whitlock near Wilson Inlet in the period 1905-19 (mostly 1907, 1909 and 1910), hitherto unpublished, were collated from museum specimens and archives. Whitlock noted 94 species comprising 65 landbirds, 10 waterbirds, 7 seabirds, and 12 non-breeding waders. Records of bird species made by other ornithologists from 1889 to 1913 indicate that the original avifauna of this region comprised 81 landbird species. In the past century four of these species (Burhinus grallarius, Pezoporus wallicus, Atrichornis clamosus and Dasyornis longirostris), as well as the waterbird Ixobrychus flavicollis, appear to have become locally extinct. Deforestation for agricultural development, with the subsequent creation of parkland and pasture, has allowed 10 landbird and 8 waterbird species to colonize the area. Whitlock's records of the seabird species Eudyptula minor and Pterodroma macroptera nesting on islands in Wilson Inlet are otherwise unreported in the literature. A comprehensive synthesis of eyewitness accounts of Aboriginal burning practices in the period 1791-1840 indicates that anthropogenic fire was frequent, prevalent in summer, and spatially extensive but in patches varying in area from c. 10-2000 ha, with a tendency for riparian vegetation to be burnt less often than uplands. Such fires could be set at the hottest part of the day, with multiple ignitions on the one day, and under windy conditions. Three bird species that are sensitive to frequent fire and now considered to be extinct locally are presumed to have had patchy distributions confined to those limited parts of the landscape naturally protected from frequent burning (vegetation along higher order streams, on steep south-facing slopes, or surrounded by expanses of granite). In addition, some of these sites may have had totemic significance to Aborigines and were thus protected from more intense or frequent fire by periodic burning using low intensity fire in spring, late autumn or early winter. The vulnerability of naturally insularized populations to inappropriate intensity or frequency of fire may explain the early demise of these species following European settlement. Few other parts of Western Australia have an avifauna so well documented at a time when agricultural development had only recently commenced. The Denmark area would therefore provide an appropriate focal region for documenting ongoing environmental change as indicated by the avifauna.
Abstract: Fire is widely used for conservation management in the savannah landscapes of northern Australia, yet there is considerable uncertainty over the ecological effects of different fire regimes. The responses of insects and other arthropods to fire are especially poorly known, despite their dominant roles in the functioning of savannah ecosystems. Fire often appears to have little long-term effect on ordinal-level abundance of arthropods in temperate woodlands and open forests of southern Australia, and this paper addresses the extent to which such ordinal-level resilience also occurs in Australia's tropical savannahs. The data are from a multidisciplinary, landscape-scale fire experiment at Kapalga in Kakadu National Park. Arthropods were sampled in the two major savannah habitats (woodland and open forest) using pitfall traps and sweep nets, in 15-20 km2 compartments subjected to one of three fire regimes, each with three replicates: 'early' (annual fires lit early in the dry season), 'late' (annual fires lit late in the dry season), and 'unburnt' (fires absent during the five-year experimental period 1990-94). Floristic cover, richness and composition were also measured in each sampling plot, using point quadrats. There were substantial habitat differences in floristic composition, but fire had no measured effect on plant richness, overall composition, or cover of three of the four dominant species. Of the 11 ordinal arthropod taxa considered from pitfall traps, only four were significantly affected by fire according to repeated-measures ANOVA. There was a marked reduction in ant abundance in the absence of fire, and declines in spiders, homopterans and silverfish under late fires. Similarly, the abundances of only four of the 10 ordinal taxa from sweep catches were affected by fire, with crickets and beetles declining in the absence of fire, and caterpillars declining under late fires. Therefore, most of the ordinal taxa from the ground and grass-layer were unaffected by the fire treatments, despite the treatments representing the most extreme fire regimes possible in the region. This indicates that the considerable ordinal-level resilience to fire of arthropod assemblages that has previously been demonstrated in temperate woodlands and open forests of southern Australia, also occurs in tropical savannah woodlands and open forests of northern Australia.
Prescribed fires have been used as a forest vegetation management tool in the eastern United States during the past decade, but concerns havebeen raised about direct or indirect adverse effects on Neotropical migrant birds species that nest in forest interior habitats. Prescribed fires were set in 1993 and 1995 in a mature hardwood forest in southern Indiana, USA, to reduce shade-tolerant understory woody vegetation and thereby increase the abundance and diversity of ground layer vegetation and seedlings of tree species that require moderate light levels (e.g., Quercus L. spp.). The objective of this study was to determine if prescribed fires reduced the abundance or reproductive success of ground- and shrub-nesting Neotropical migrant bird species. The burned area and an adjacent unburned area were studied during the summers of 1996 and 1997. An unlimited-radius point count method was used to determine relative abundance. Nests were monitored to determine fledging success. Vegetation structure was quantified at nest sites and at random points to assess fire effects and bird nest-site selection. Abundance of birds in this nesting guild was greater in the unburned area during both years. The greatest difference in abundance was for ovenbird (Seiurus aurocappilus Linnaeus). The probability of nest success for all bird species in this nesting guild combined, determined by the Mayfield method, was significantly lower in the burned area (0.125) than in the unburned area (0.291). Abundance of the brood parasite brown-headed cowbird (Molothus ater Boddaert) did not differ between burned and unburned areas. However, the probability of nest success for parasitized nests (0.140) was lower than that of unparasitized nests (0.735). The mean number of host young fledged from successful nests was significantly lower in parasitized nests (1.3) than from unparasitized nests (3.0). Prescribed fires significantly reduced vegetative cover in the burned area. Nest sites in the burned area had higher vegetative cover than random points, indicating that birds may have selected nest sites that were less affected by the fire. While prescribed fires that burn in a "natural" hit-or-miss pattern may retain nesting habitat for bird species in this nesting guild, lower nest success in the burned area indicates that management for desirable vegetation and for this nesting guild may not be compatible within the same forest stand at the same time. This argues for planning at a landscape level to attain objectives for both vegetation composition and maintenance of bird species diversity.
Abstract: After a large crown fire in Arizona, we examined the direct and indirect effects of fire and herbivory (and their interaction) on the regeneration of aspen (Populus tremuloides) and arthropod species richness and abundance. We used elk exclosures covering 150 ha and other experiments to examine these interactions. Several major patterns emerged. First, in the absence of elk, there is a positive relationship between burn severity and the regeneration of aspens via asexual reproduction. Specifically, aboveground biomass of aspen resprouts was 10 times greater at sites of high burn severity than in sites of intermediate burn severity, and there was virtually no aspen regeneration without fire. Second, elk selectively browsed aspen ramets in high-severity burn sites two times more intensely than aspen ramets in intermediate-severity burn sites, largely negating the enhanced regeneration that would have otherwise occurred, thus resulting in three times greater regeneration in intermediate burn sites than in high burn sites. Third, fire and elk browsing had opposing impacts on an arthropod community composed of 33 taxa from 11 orders and 21 families. Fire severity alone showed no effect on arthropod richness and abundance; however, intermediate-severity fire and moderate levels of elk browsing resulted in 30% greater richness and almost 40% greater abundance. In contrast, high-severity fire and high levels of elk browsing resulted in 69% lower arthropod richness and 72% lower abundance. Fourth, the interaction of fire intensity and selective elk browsing resulted in four arthropod community types where the overall mosaic produced the greatest diversity. Our study demonstrates that patterns can completely reverse depending on the factors involved. This argues against a reductionist perspective and argues for studies incorporating greater complexity. At the very least, we need to be aware of such biases and consider how they may alter important decisions that affect basic ecological theory and management practices.
Abstract: Banksia woodland is a seasonally arid and fire-prone environment. Although a seemingly inhospitable environment for frogs, seven species were recorded in pitfall-trapping carried out in six areas of Banksia woodland. These areas had different fire histories, ranging from recently burned to unburned for 23 years. One of the areas was burned during the course of this study. Three species made up 95% of captures; Helleioporus eyrei, Limnodynastes dorsalis, and Myobatrachus gouldi. Annual numbers of captures of H. eyrei were not generally affected by fire or increasing time after fire. L. dorsalis, and to a lesser extent, M. gouldii were caught in higher numbers in long-unburnt areas than in recently burnt areas. Variation in the abundance of L. dorsalis and M. gouldii with time after fire did not appear to be related to changes in leaf litter and vegetation density, or to the abundance of invertebrates as potential prey.
Abstract: Fire influences the presence and distribution of plants, and their associated plant diseases in natural ecosystems. Plots at a Long Term Ecological Research facility in Cedar Creek Minnesota, were utilized to investigate the effects of fire on the annual changes in rust infection in this natural prairie. Infection by P. andropogonis was measured on both it's hosts, comandra (C), and big bluestem (BBS), over a four year period in two fields, one burned every fourth year, and one without burns. Fire reduced aecia on C by over 96 percent compared to years previous and following the fire, but there was no change in the overall average uredinal infection levels in BBS plots within or between fields of that year. This is likely due to the efficiency of uredinal spore dispersal. However, variation in rust levels on individual BBS plots between years was affected by fire. Simple regression of rust levels in pairs of years gave R2=0.06, regressing the year following the burn to the year of the burn, compared to R2=0.37 for the non-burned field, supporting that fire can disrupt perennial disease cycles. Field differences in R2 values hold true for all year by year comparisons.
Abstract: Acacia erioloba woodlands provide important forage and shade for wildlife in northern Botswana. Mortality of mature trees caused by browsing elephants has been well documented but the lack of regeneration of new trees had received little attention. Annual growth of new shoots and changes in height were measured to determine the influence of elephants and small ungulate browsers, rainfall and fire on the growth and survival of established A. erioloba seedlings from 1995 to 1997 in the Savuti area of Chobe National Park. All above-ground vegetation was removed from 40% of established seedlings in 1995 and 28% in 1997 by browsing elephants, and the mean height of remaining seedlings decreased from >550 mm to <300 mm. When seedlings browsed by kudu, impala and steenbok but not elephants are considered, mean seedling height increased <50 mm per year, even though mean new shoot growth remaining at the end of the dry season was 100-200 mm. Fires burned portions of the study area in 1993 and 1997, killing above-ground vegetation, but most established A. erioloba seedlings survived, producing coppice growth from roots. While elephants and fire caused the greatest reduction in established seedling height and number, small browsers suppressed growth, keeping seedlings vulnerable to fire and delaying growth to reproductive maturity.
Abstract: Little is known of the effects of fire on lesser prairie-chicken (Tympanuchus pallidicinctus) habitat in shinnery oak (Quercus havardii) communities. Our objective was to determine the influence of seasonal prescribed fire, at 1 and 2 years post-treatment, on the quality of nesting habitat, foraging and brooding habitat, and thermal and escape cover. In each of 3 study sites in western Oklahoma, 12 60X30-m plots were seasonally burned, annually burned, or left unburned, and an array of habitat variables were measured at 1 and 2 years post-fire. During both periods, canopy coverage of shrubs decreased (Pltoreq0.01) with fall and spring fire. Nesting grass cover decreased (P=0.007) with fall and spring burning at 1 year post-fire. Visual obstruction in May and January decreased (Pltoreq0.001) with burning in all seasons. Burning in all seasons increased warm- (gtoreq100% increase, P<0.001) and cool- (gtoreq200% increase, P=0.026) season forb coverage in year 1 and grasshopper density (Pltoreq0.1 00) in both years. Shinnery oak mast, leaf bud, and catkin production failed at 1 year post-fire At 2 years post-fire, cool-season forb cover increased (P=0.014) with fall and spring burning and winter (January) forb frequency increased (P=0.047) 190% with burning in all seasons. Prescribed fire appears to be an effective tool to increase abundance of growing-season forbs and sedges, winter forbs, and grasshoppers associated with quality Foraging and brooding habitat. Nesting habitat and thermal and escape cover are impacted negatively by fire, particularly spring fire, due to a reduction in overhead and horizontal cover and reduced abundance of important nesting grasses. Our data suggest a 2- to 3-year recovery period for nesting habitat following burning. Negative impacts of fire on nesting habitat and thermal and escape cover can be reduced by burning in seasons other than spring, decreasing burn size, and interspersing burned and unburned areas.
Abstract: Surprisingly little research has been done to partition the contribution of catastrophic disturbance from that of small-scale individualistic mortality events on riparian large woody debris (LWD) recruitment. This study compared the impact of both processes on recruitment through simulation of several catastrophic disturbances (a spruce beetle outbreak, a moderately intense fire, and a clearcut) and undisturbed (individualistic mortality only) old growth for a small headwater stream in the Intermountain West of the United States. All scenarios progressed through a two-stage process, with the Forest Vegetation Simulator growth and yield model controlling forest dynamics and a postprocessor (CWD, version 1.2) predicting riparian LWD recruitment. Projections indicate that individualistic-only conditions delivered 2.5 m3 LWDcntdot100 m reach-1cntdot10-yr cycle-1; while the spruce beetle-, fire-, and clearcut-affected stands averaged 2.9, 3.2, and 1.5 m3 LWDcntdot100 m reach-1cntdotcycle-1, respectively. Stands impacted by natural catastrophic disturbance significantly (P < 0.05) increased cumulative (300 yr) LWD recruitment over the individualistic-only scenario, whereas clear-cutting significantly decreased total delivery. In-stream LWD loads, relatively stable in undisturbed riparian zones, fluctuated sharply under catastrophic disturbance. Peak channel loads associated with natural perturbation occurred apprx30 yr after the event while debris volumes under clear-cutting immediately declined. The postevent recruitment and in-stream LWD stocks of all disturbance scenarios eventually fell below undisturbed conditions, requiring decades to recover historical volumes. Catastrophic disturbances induced such steep oscillations in riparian LWD load that the systems experiencing frequent large-scale perturbations never achieved a long-term steady state, as some have postulated. Because of the inflation in cumulative LWD delivery, it may prove advantageous to encourage (or imitate) some catastrophic disturbance in forests along streams noticeably depauperate of LWD.
Abstract: A quantitative analysis of the effect of fire regime on the abundance of common lizard species and genera and the species richness of two lizard groups in Kakadu National Park (12 degrees S) is presented. A surprising range of relationships between species abundance and components of fire regimes was revealed. Carlia amax, Heteronotia binoei and Carlia gracilis appear to be fire-sensitive, Diporiphora bilineata and Carlia triacantha are favoured by early hot fires, Cryptoblepharus plagiocephalus seems relatively unaffected, Carlia foliorum seems very tolerant of fires, while Ctenotus and Sphenomorphus spp. are favoured by low intensity, patchy fires with high intensity spots.
Lizard species experiencing the high-frequency fire regimes of the savannas and dry forests of the Australian wet-dry tropics are not able to select habitat at different stages of regeneration after fire but select habitat produced by fires of different types. The implication for management is that no one fire regime is optimal for the fauna as a whole. A range of fire regimes within a park should be maintained in order to retain the whole fauna.
Abstract: Densities of gopher tortoises were compared with habitat characteristics in scrub and in flatwood habitats on the Kennedy Space Center, Florida. Tortoises were distributed widely among habitat types and did not have higher densities in well-drained (oak-palmetto) than in poorly-drained (saw palmetto) habitats. Fall densities of tortoises ranged from a mean of 2.7 individuals/ha in disturbed habitat to 0.0 individuals/ha in saw palmetto habitat. Spring densities of tortoises ranged from a mean of 2.5 individuals/ha in saw palmetto habitat to 0.7 individuals/ha in oak-palmetto habitat. Densities of tortoises were correlated positively with the percent herbaceous cover, an indicator of food resources. Plots were divided into three burn classes; these were areas burned within three years, burned four to seven years, and unburned for more than seven years prior to the study. Relationships between densities of tortoises and time-since-fire classes were inconsistent.
Abstract: Fire-prone savanna ecosystems in southern African conservation areas are managed by prescribed burning in order to conserve biodiversity. A prescribed burning system designed to maximise the benefits of a diverse fire regime in savanna conservation areas is described. The area burnt per year is a function of the grass fuel load, and the number of fires per year is a function of the percentage area burnt. Fires are point-ignited, under a range of fuel and weather conditions, and allowed to burn out by themselves. The seasonal distribution of planned fires over a year is dependent on the number of fires. Early dry season fires (May-June) tend to be small because fuels have not yet fully cured, while late season fires (August-November) are larger. More fires are ignited in the early dry season, with fewer in the late dry season. The seasonality, area burnt, and fire intensity are spatially and temporally varied across a landscape. This should result in the creation of mosaics, which should vary in extent and existence in time. Envelopes for the accumulated percentage to be burnt per month, over the specified fire season, together with upper and lower buffers to the target area are proposed. The system was formalised after 8 years of development and testing in Pilanesberg National Park, South Africa. The spatial heterogeneity of fire patterns increased over the latter years of implementation. This fire management system is recommended for savanna conservation areas of >20 000 ha in size.
Abstract: Prior to Anglo-European settlement, fire was a major ecological process influencing the structure, composition and productivity of shortgrass prairie ecosystems on the Great Plains. However during the past 125 years, the frequency and extent of grassland fire has dramatically declined as a result of the systematic heavy grazing by large herds of domestic cattle and sheep which reduced the available levels of fine fuel and organized fire suppression efforts that succeeded in altering the natural fire regime. The greatly diminished role of recurrent fire in these ecosystems is thought to be responsible for ecologically adverse shifts in the composition, structure and diversity of these grasslands, leading specifically to the rise of ruderal species and invasion by less fire-tolerant species. The purpose of this study was to evaluate the ecological effects of fire season and frequency on the shortgrass prairie and to determine the means by which prescribed fire can best be restored in this ecosystem to provide the greatest benefit for numerous resource values. Plant cover, diversity, biomass and nutrient status, litter cover and soil chemistry were measured prior to and following fire treatments on a buffalograss-blue grama shortgrass prairie in northeastern New Mexico. Dormant-season fire was followed by increases in grass cover, forb cover, species richness and concentrations of foliar P, K, Ca, Mg and Mn. Growing-season fire produced declines in the cover of buffalograss, graminoids and forbs and increases in litter cover and levels of foliar P, K, Ca and Mn. Although no changes in soil chemistry were observed, both fire treatments caused decreases in herbaceous production, with standing biomass resulting from growing-season fire similar to600kg/ha and dormant-season fire similar to1200kg/ha, compared with controls similar to1800kg/ha. The initial findings of this long-term experiment suggest that dormant-season burning may be the preferable method for restoring fire in shortgrass prairie ecosystems where fire has been excluded for a prolonged time period.
Abstract: We used the computer program RAMAS to explore the sensitivity of an extinction-risk model for the Gila trout (Oncorhynchus gilae) to management of wildfires and number of populations of the species. The Gila trout is an endangered salmonid presently restricted to very few headwaters of the Gila and San Francisco river tributaries in southwestern New Mexico. Life history data for 10 extant populations were used to examine sensitivity of the species' viability to changes in a variety of factors including population size, fecundity, life stage structure, number of populations, severity and probability of forest fires, and a regulated fishery. The probability and severity of forest fires and number of populations had the greatest effect on viability. Results indicate that successful conservation of Gila trout requires establishment of additional populations and reduction of the severity of forest fires through a program incorporating more frequent, but less severe, fires.
Abstract: In western North America, major wildfires often now result in stand-replacement events and natural resource losses for many decades post-burn. Fire severity has been exacerbated by past fire suppression that has allowed large fuel load accumulations. To reduce woody debris and restore the ecological integrity of western forests, prescribed burning is increasingly used as a regional management tool. However, we do not understand the effects of either wildfire or prescribed fires on amphibians in stream, riparian and terrestrial habitats in western forests. Terrestrial amphibians, macroinvertebrates and other animals are surface active during periods of rainfall or high moisture. Wildland fire usually starts in the hot, dry summers typical of the more acrid Western and Mediterranean climates and may have less effect on resident biota than prescribed fires often conducted during the late fall to spring rainy season, when there is sufficient moisture to prevent crown fires. Still, intense wildfires may result in increased erosion and sediment or changes in soil chemistry impacting downstream aquatic environments. To our knowledge, no published reports exist on effects of fire on the aquatic herpetofauna of the Pacific Northwest. Research efforts now underway include new studies of wildland fires in Oregon and Idaho on aquatic amphibians, and studies on the effects of prescribed fire on terrestrial salamanders and associated forests in the Klamath Province along the Oregon-California border. These will help evaluate the cumulative effects of fuels reduction on amphibian population and habitat structure, and provide guidelines to better manage for wildlife species characteristic of western forests. In the Pacific Northwest, investigations of fire effect son wildlife are severely lacking relative to the vast acreage, economic value, and biodiversity of its forest ecosystems. Given the increasing prominence of wildfire and prescribed burning in many western forest systems, we suggest more resources will be devoted to such research endeavors, and that hey include other sensitive groups of wildlife such as mollusks.
Abstract: Few intensive studies have been conducted on reptile populations of the tallgrass prairie. In addition, the effects of fire on these populations are also largely unknown. I established drift fence arrays connected to funnel traps to study the community composition and seasonal activity of reptiles found on the Konza Prairie Research Natural Area located near Manhattan, Kansas. This design also gave me the opportunity to examine the response of reptile populations to a spring wildfire. A total of 657 individuals representing 12 species were captured from 1994-1996. The results suggest that one species, Coluber constrictor, may respond negatively to recent fire.
Abstract: Natural ecosystems globally are often subject to multiple human disturbances that are difficult to restore. A restoration experiment was done in an urban fragment of native coastal sage scrub vegetation in Riverside, California that has been subject to frequent fire, high anthropogenic nitrogen deposition, and invasion by Mediterranean annual weeds. Hand cultivation and grass-specific herbicide were both successful in controlling exotic annual grasses and promoting establishment of seeded coastal sage scrub vegetation. There was no native seedbank left at this site after some 30 years of conversion to annual grassland, and the only native plants that germinated were the seeded shrubs, with the exception of one native summer annual. The city green-waste mulch used in this study (C:N of 39:1) caused short-term N immobilization but did not result in decreased grass density or increased native shrub establishment. Seeding native shrubs was successful in a wet year in this Mediterranean-type climate but was unsuccessful in a dry year. An accidental spring fire did not burn first-year shrubs, although adjacent plots dominated by annual grass did burn. The shrubs continued to exclude exotic grasses into the second growing season, suggesting that successful shrub establishment may reduce the frequency of the fire return interval.
Abstract: Stand restoration of low-quality, mixed pine-hardwood ecosystems containing a Kalmia latiforilia L. dominated understory, through cutting, buring, and planting of Pinus strobus L., is common on xeric souther Appalachian forest sites. WE examined the effects of this tratment on early vegetation composition and diversity. Four 13-year-old stands were examined. Two of the four stands were mechanically released at age 6. Density and basala area were estimated for understory and overstory components, and density and percent cover for the herb component. Species diversity (Shannon-Wiener index) was estimated and comparisons were made with an untreated reference stand that was typical of stands receiving site preparation burning in the southern Appalachians. Overstory and herb diversity estimates were significantly lower for the reference stand that for the 13-year-old stands.
Abstract: Changes in aboveground and forest floor mass, carbon (C), and nitrogen (N) pools were quantified on three sites in the southern Appalachians 2 yr after felling and burning, Before fel ling and burning, stands were characterized by sparse overstories and dense Kalmia latifolia L. understories, Two years after burning, foliar C and N pools had reached 25% and 29% of pretreatment levels, respectively. Foliar N concentrations were not different from pretreatment values, Standing wood C and N pools were 1% and 2%, respectively, of pretreatment values, Wood N concentrations were significantly higher on two sites, likely related to differences in fire intensity, Forest floor N content 2 yr after burning was 90% of pretreatment levels, most contained in unconsumed large woody material. Forest floor mass was significantly lower in the Oi layer and unchanged in the Oe+Oa layers. Forest floor N concentrations were generally lower after treatment. The site with the least intense fire and the lowest mass loss from the forest floor had the highest forest floor, foliage, and wood N concentrations 2 yr after burning. Site recovery after felling and burning was a function of five severity and the capacity for site-nutrient retention through plant uptake.
Abstract: We sampled amphibians on 3 red alder (Alnus rubra) sites 1 year before and 1 and 2 years after the following treatments were applied to each site: (1) control (uncut), (2) clearcut and broadcast burned, and (3) clearcut, broadcast burned, and then sprayed with the herbicide glyphosate. All sites included uncut riparian buffer strips. For 3 of the 6 species with greater than or equal to 20 captures in pitfall traps, we did not detect changes in capture rates after clearcutting. Capture rates of ensatinas (Ensatina eschscholtzii) and Pacific giant salamanders (Dicamptodon tenebrosus) decreased after logging. Capture rates of western redback salamanders (Plethodon vehiculum) increased the first year after logging, probably because the salamanders sheltered in pitfalls, but effects on populations were unclear. Logging did not significantly alter capture rates of rough-skin newts (Taricha granulosa), Dunn's salamanders (P. dunni), and red-legged frogs (Rana aurora). Planning the location and timing of clearcuts or other silvicultural practices over a landscape and retaining riparian buffer strips may be necessary to ensure long-term persistence of Pacific giant salamanders. We did not detect any effects of herbicide spraying on capture rates. Capture rates for rough-skin newts and red-legged frogs were higher in uncut red alder stands than in Douglas-fir (Pseudotsuga menziesii) stands sampled in other studies, an indication that, when red alder stands are converted to Douglas-fir, some alders should be left adjacent to streams to provide habitat for these species and other hardwood associates.
Abstract: Prescribed burning is a common method to eliminate sagebrush (Artemisia spp.) and has been suggested as a tool to enhance the habitat of sage grouse (Centrocercus urophasianus). Effects of this practice on sage grouse have not been evaluated rigorously. We studied effects of prescribed fire on lek (traditional breeding display areas) attendance by male sage grouse occupying low-precipitation (<26 cm) sagebrush habitats in southeastern Idaho from 1986 through 1994. During the preburn period (1986-89), average declines for male attendance were 48% and 46% for treatment and control leks, respectively. Lek counts were similar for treatment and control leks during the preburn years (G-test, 0.25>P>0.10). During the postburn period (1990-94), male attendance at treatment leks declined 90% and control leks declined 63%. Although declines were similar between treatment and control leks during the preburn period, postburn declines were greater for treatment than control leks (0.05<P<0.10). We rejected the null hypothesis that for the 2 largest leks in both the treatment and control areas, counts were independent of years for preburn (0.05<P<0.10) and postburn (Pltorsim0.05) periods and concluded that breeding population declines became more severe in years following fire. Prescribed burning negatively affected sage grouse in southeastern Idaho and should not be used in low-precipitation sagebrush habitats occupied by breeding sage grouse.
Abstract: Ecosystem management is a theoretical framework in which land managers attempt to approximate natural disturbance with harvesting practices. In the mixedwood boreal forest of northeastern Alberta, Alberta-Pacific Forest Industries Inc. alters cutblock size, structure, and distribution over the landscape to simulate fires, the dominant disturbance type. In 1997 and 1998, we sampled for Rana sylvatica (Le Conte) and Pseudacris triseriata maculata (Wied-Neuwied) near Owl River and Mariana Lake, Alberta, in undisturbed, harvested, and naturally burned landscapes. We compared patterns of distribution and relative abundance using transects, time-constrained lake margin searches, and opportunistic detections. In 1998, we characterized the understory, shrub layer, and canopy layer on each transect. We used stepwise logistic regression to describe microhabitat use by each species. We did not detect consistent differences between burned and logged areas. This may reflect pre-treatment variation in regional habitat. Our data suggest that the presence of R. sylvatica is related to deciduous leaf litter, and that both species may require extensive ground cover and moist soil conditions. Although the microhabitat descriptions we present can be used to plan future harvests, further work is required to determine the effectiveness of ecosystem management in the boreal forest.
Abstract: Restoration of many terrestrial plant communities involves the reintroduction of fire. However, there have been few studies of the effects of fire on the avifauna during the restoration process. To study the effects of oak savanna restoration on avian communities, breeding birds were censused and the vegetation structure documented in seven experimental burn units (8-18 ha) that had experienced different frequencies of controlled burns during the past 31 years (0-26 burns). Data were analyzed with both direct and indirect gradient analyses using multivariate techniques. The results showed that, as savanna restoration proceeded, there was a general decline in predominantly insectivorous species, particularly those that feed in the upper canopy region (leaves and air space), and a general increase in omnivorous species, particularly those that feed on the ground and in the lower canopy. Insectivorous bark gleaners (woodpeckers) also increased during restoration and were correlated with the increase in standing dead trees resulting from the fires. Overall, savanna restoration resulted in increases in the abundance of many open country bird species, including many species that have been declining in central and eastern North America, including red-headed woodpecker, Baltimore oriole, eastern kingbird, vesper sparrow, field sparrow, lark sparrow, brown thrasher, American goldfinch, and brown-headed cowbird. The shifts in species and guilds were correlated with changes in burn frequency and the macro vegetation structure-tree and shrub density, leaf area index, and relative proportion of standing dead trees. The findings show that savanna restoration can increase bird diversity and provide important habitat for uncommon or declining bird species. These birds are most likely attracted to one or more of the distinctive habitat features of the restored savanna environments, including scattered mature trees, standing dead trees and snags, and presence of both shrubby and grassland vegetation. The findings also suggest that restoration ecologists and wildlife biologists will need to work together to achieve desired goals, since different types of savanna restoration efforts may produce different effects on the breeding bird community.
Abstract: The application of fire as a management tool is often used to change the species composition of the vegetation and its cover to maintain plant communities in a specific successional stage. This study investigates the influence of two fire treatments (a head and a back fire) on the plateau grassland communities in the Mountain Zebra National Park (MZNP). The production of herbage yield on grazed areas and areas protected from grazing which were subjected to two fire treatments, were compared with that of an unburnt control area subjected to grazing in the same homogenous grassland over two growing seasons. No differences were found in herbage production between the two fire treatment areas. After the burn the grazing exclosures achieved the same herbage yield as the control area within two growing seasons. In comparison, the grazed areas could after the burn only achieve a herbage yield equal to 55.7% of that of the control area. The results indicate that fire stimulates active vegetation growth on the plateau grasslands in MZNP leading to a higher production rate and better utilisation by game.
Abstract: The Florida panther (Puma concolor coryi) is one of the most endangered mammals in the world, with only 30-50 adults surviving in and around Florida Panther National Wildlife Refuge and the adjacent Big Cypress National Preserve, hlanagers at these areas conduct annual prescribed burns in pine (Pinus sp.) as a cost-effective method of managing wildlife habitat. Our objectives were to determine if temporal and spatial relationships existed between prescribed fire and panther use of pine. To accomplish this, we paired fire-event data from the Refuge and the Preserve with panther radiolocations collected between 1989 and 1998, determined the time that had elapsed since burning had occurred in management units associated with the radiolocations, and generated a frequency distribution based on those times. We then generated an expected frequency distribution, based on random use relative to time since burning. This analysis revealed that panther use of burned pine habitats was greatest during the first year after a management unit was burned. Also, compositional analysis indicated that panthers were more likely to position their home ranges in areas that contained pine. We conclude that prescribed burning is important to panther ecology. We suggest that panthers were attracted to <1-year-old burns because of white-tailed deer (Odocoileus virginianus) and other prey responses to vegetation and structural changes caused by the prescribed fires. The strong selection for stands burned within 1 year is a persuasive indication that it is the bunting in pine, rather than the pine per se, that most influenced habitat use. Before burning rotation lengths are reduced, however, we suggest managers determine effects of shorter burning intervals on vegetation composition and evaluate the landscape-scale changes that would result.
Abstract: The four frog species in the Geocrinia rosea complex occur in state forest in southwest Western Australia. Fire management of these forests involves fuel-reduction burning with an average rotation of five to nine years. In this study we examined the impact of fire on Geocrinia lutea by counting calling males in six pairs of burned and control sites from 1992 to 1994. The immediate impact of the fire on G. lutea adults, and the survival of G. lutea eggs and larvae after the fire, were also addressed. We found that fuel-reduction burning in spring was associated with a significant decline in the number of calling males. The populations had not recovered two years after the fire. Up to 29% of the calling males may have been killed in the fire. Egg and larval survival was not significantly different between treatments. However, the treatments did differ in the cause of death, with higher in-situ egg death and lower predation at burned sites. The short-term impact of spring fuel-reduction burns may pose a serious threat of extinction for very small populations. The endangered species Geocrinia alba has many small, isolated populations and frequent fire may therefore be inimical to their survival. However, we do not know if there is a long-term effect. Populations may or may not have time to recover between fires.
Abstract: We describe our experience as biologists/resource advisors working with firefighting personnel to reduce the risk of impacts and disturbances to desert tortoises and their habitats. Pre-fire season planning is essential preparation for risk assessment and identifying sensitive areas of habitat between biologists/resource advisors and fire managers. Having resource advisors present at the onset of fire operations can prevent potentially destructive activities related to the logistics of having vehicles in habitat and providing for the needs of groups of fire suppression personnel. Rehabilitation of road heads in tortoise habitat is a useful means of deterring further long-term degredation of habitat in some cases. We provide two appendices for use in the field: 1) an outline of fire management activities to be used by fire managers, and 2) an outline of a shift briefing used to educate firefighters at the scene of a fire. These prescriptions for action and education were developed for use in the northeast Mojave Desert of Utah and Arizona. These procedures are not universal in application and should be tailored to local needs and consideration of other resource values than tortoises. THe Sonoran Desert of Arizona differs substantially in physiography, and plant species composition and fuel loads. THerefore, we should consider habitat characteristics and habitat use by tortoises in the Sonoran Desert of Arizona specifically to assess the possible effects of fire suppression activities and to minimize adverse impacts to desert tortoises and their habitats. This approach could be useful for protecting other sensitive species and habitats in a variety of areas.
Abstract: Stratigraphic and geomorphic evidence indicate floods that occur soon after forest fires have been intermittent but common events in many mountainous areas during the past several thousand years. The magnitude and recurrence of these post-fire flood events reflects the joint probability between the recurrence of fires and the recurrence of subsequent rainfall events of varying magnitude and intensity. Following the May 1996 Buffalo Creek, Colorado, forest fire, precipitation amounts and intensities that generated very little surface runoff outside of the burned area resulted in severe hillslope erosion, floods, and streambed sediment entrainment in the rugged, severely burned, 48 km(2) area. These floods added sediment to many existing alluvial fans, while simultaneously incising other fans and alluvial deposits. Incision of older fans revealed multiple sequences of fluvially transported sandy gravel that grade upward into charcoal-rich, loamy horizons. We interpret these sequences to represent periods of high sediment transport and aggradation during floods, followed by intervals of quiescence and relative stability in the watershed until a subsequent fire occurred.
An alluvial sequence near the mouth of a tributary draining a 0-82 km(2) area indicated several previous post-fire flood cycles in the watershed. Dendrochronologic and radiocarbon ages of material in this deposit span approximately 2900 years, and define three aggradational periods. The three general aggradational periods are separated by intervals of approximately nine to ten centuries and reflect a 'millennium-scale' geomorphic response to a closely timed sequence of events: severe and intense, watershed-scale, stand-replacing fires and subsequent rainstorms and flooding. Millennium-scale aggradational units at the study site may have resulted from a scenario in which the initial runoff from the burned watershed transported and deposited large volumes of sediment on downstream alluvial surfaces and tributary fans. Subsequent storm runoff may have produced localized incision and channelization. preventing additional vertical aggradation on the sampled alluvial deposit for several centuries. Two of the millennium-scale aggradational periods at the study site consist of multiple gravel and loam sequences with similar radiocarbon ages. These closely dated sequences may reflect a 'multidecade-scale' geomorphic response to more frequent. but aerially limited and less severe fires, followed by rainstorms of relatively common recurrence.
Abstract: In April 1995, the USDA Forest Service conducted a prescribed burn along with a south-facing slope of southern Appalachian watershed, Nantahala National Forest, western NC. Fire had been excluded for over 70 years and the purpose of the burn was to create a mosaic of fire intensities to restore a degraded pine/hardwood community and to stimulate forage production and promote oak regeneration along a hillslope gradient. Permanent plots were sampled at three locations along a gradient from 1500 to 1700 m. Plot locations corresponded to three community types: mesic, near-riparian cove (low slope); dry, mixed-oak (mid slope); and xeric, pine/hardwood (ridge). Before burning (1994-1995) and post-burn (summer, 1995 and summer, 1996) vegetation measurements were used to determine the effects of fire on the mortality and regeneration of overstory trees, understory shrubs, and herbaceous species. After the burn, mortality was highest (31%) at the ridge location, substantially reducing overstory (from 26.84 pre-bum to 19.05 m(2) ha(-1) post-burn) and understory shrub (from 6.52 pre-burn to 0.37 m(2) ha(-1) post-bum) basal area. At the mid-slope position, mortality was only 3%, and no mortality occurred at the low slope. Not surprisingly, percent mortality corresponded to the level of fire intensity. Basal area of Kalmia latifolia, Gaylussacia baccata, and Vaccinium spp. were substantially reduced after the fire, but density increased due to prolific sprouting. The prescribed fire had varying effects on species richness and diversity across the hillslope gradient. On the ridge, diversity was significantly increased in the understory and herb-layer, but decreased in the overstory. On the mid slope, no change was observed in the overstory, but diversity significantly decreased in the understory. On the low slope, no change was observed in the overstory or understory. (C) 1999 Elsevier Science B.V. All rights reserved.
Abstract: The Florida box turtle, Terrapene carolina bauri, ranges over most of central and eastern peninsular Florida and the Keys. Over the range of T. c. bauri, the pine flatwoods habitat with which it is best associated is subject to periodic burning. The authors look at the extent to which the Florida box turtle is adversely affected by such events by examining a series of T. c. bauri in the collections of the United States National Museum of Natural History, Smithsonian Institution, and George Mason University. Their observations indicate that fire may play a critical role in the ecology of Florida box turtle populations. Unfortunately, so little has been published on the life history of this animal that it is difficult to assess its ecological and behavioral requirements with any degree of certainty.
Abstract: Evidence of direct mortality to vertebrates was gathered following controlled spring burns in a reestablished prairie in eastern Nebraska. During 3 years (1974-1976) in which observations were made, several species were killed by fires, including: cottontail rabbits (Sylvilagus floridanus), western harvest mice (Reithrodontomys megalotis), voles (Microtus pennsylvanicus and M. ochrogaster), bull snakes ( Pituophis melanoleucas), plains garter snakes (Thamnophis radix) and red-sided garter snakes (T. sirtalis). Young harvest mice pups were partially susceptible to spring prairie fires; morrtality to these on a 22.8-ha section burned 26 April 1976 was estimated at between 208 and 522 individuals. Many eggs of ground-nesting birds were destroyed by the fires; species included were ring-necked pheasant (Phasianus colchicus), bobwhite quail (Colinus virginianus), mallard duck (Anas platyrhynchus) and meadowlark (Sturnella neglecta).
Abstract: The effects of habitat manipulations on Texas horned lizards (Phyrnosoma cornutum) and their main prey, harvester ants (Pogonomyrmex spp.) were studied in South Texas. The relative abundance of lizards, their scat, and active harvester ant mounds was assessed on 1-ha plots that were manipulated with either prescribed burning, disking, burning and disking combination, grazing, or land in the Conservation Reserve Program (CRP). We determined differential habitat use or avoidance using Chi-square analysis and Bonferroni Z-statistics to control the experiment-wise error probability at 10%. Lizards used burned plots disproportionately more, were neutral in their use of the disked and grazed plots, and under-utilized the burned and disked combination and CRP plots. Analysis of scat led to similar conclusions in relation to burned, grazed, and CRP plots, but scats were distributed on combination plots pro rata to availability and were underrepresented on the disked plots. No difference was detected in the relative abundance of active ant mounds among the 5 land management practices. Even though Texas horned lizards preferentially used areas that were recently burned, the process of burning may harm them due to the shallow depths in which they hibernate.
Abstract: Federal land managers in the western United States are interested in the potential of prescribed fire as a tool to decrease fuel loads, increase vegetational heterogeneity, and increase faunal diversity in various ecosystems. I tested whether implementation of a prescribed fire program by the US Forest Service in a watershed in the central Great Basin had significant effects on butterfly species richness and composition. I monitored butterfly communities during the first two years after implementation in five to seven burn units and controls in the watershed. To estimate baseline spatial and temporal variation in butterfly communities in the greater ecosystem, I also monitored butterflies in five untreated canyons outside the project area. Butterfly species richness and butterfly species composition (measured as community similarity) did not differ significantly between burn units and controls. Geographic location had statistically significant effects on species richness. Butterfly species composition of individual locations varied over time, as did the magnitude of that variation. These results emphasize that standardized, repeatable monitoring protocols are vital for evaluating the effects of experimental management treatments and for predicting and assessing the effects of future management strategies and environmental changes.
Abstract: Ponderosa pine (Pinus ponderosa), Jeffrey pine (P. jeffreyi), longleaf pine (P. palustris), and south Florida slash pine (P. elliotti var. densa) are fire resisters. Trees of these species are able to survive the direct effects of wildfires. Monterey pine (P. radiata), knobcone pine (P. attenuata), sand pine (P. clausa), and jack pine (P. banksiana) are fire evaders. Trees of these species are killed by wildfire, but species survive on the postfire site via seed germination. Needles were burned in a 2x2 factorial experiment to compare these eight species, all of which are prominent in fire-related communities. The experiment tested two factors-fire adaptive strategy (resisters vs. evaders), geographic region (western vs. eastern United States)-and interactions between those two factors. Flame height, flame time, ember time, burn time, percent fuel combusted, and mean rate of weight loss were measured. Longleaf pine, ponderosa pine, and south Florida slash pine had the highest values for flame height, percent fuel combusted, and mean rate of weight loss. Knobcone pine and Monterey pine had the longest ember time and burn time. Sand pine and jack pine had the longest flame time. Resisters tested highest in flame height, percent fuel combusted, and mean rate of weight loss. Evaders had greater flame and burn times. Western pines were significantly greater than eastern pines in all burning characteristics except flame time and mean rate of weight loss. Significant interactions between fire adaptive strategy and geographic region existed for all burning characteristics except mean rate of weight loss. The interaction was accounted for primarily by differences between western evaders, which had some of the highest values for each characteristic, and eastern evaders, which had some of the lowest values.
Abstract: As part of the Wine Spring Creek ecosystem management project on the Natahala National forest, North Carolina, we assessed the effects of a community restoration fire on small mammals and herpetofauna in the upper slope pitch pine (Pinus rigida) stands, neighboring mid-slope oak (Quercus spp.) stands and rhododendron (Rhododendron maximum) dominated riparian areas during 1995 and 1996. Using drift-fence arrays with pitfalls and snap-trapping, we collected these small mammals: masked shrew (Sorex cinereus), smoky shrew (S. fumeus), water shrew (S. palustris), pygmy shrew (S. hoyi), northern short-tailed shrew (Blarina brevicauda), deer mouse (peromyscus maniculatus), white-footed mouse (P. leucopus), golden mouse (Ochrotomys nuttalli), southern red-backed vole (Clethrionomys gapperi), pine vole (Microtus pinetorum) and woodland jumping mouse (Napaeozapus insignis). Herpetofauna collected fom drift-fence arrays and time-constrained searches included: eastern newt (Notophtalmus viridescens), seepage salamander (Desmognathus aeneus), mountain dusky salamander (D. ochrophaeus), Blue Ridge two-lined salamander (Eurycea wilderae), spring salamander (Gyrinophilus porphyriticus), Jordan's salamander (Plethodon jordani), wood frog (Rana sylvatica), five-lined skink (Eumeces fasciatus), eastern garter snake (Thamnophis sirtalis), and northern ringneck snake (Diadophis punctatus). Prior to the prescribed community restoration fire in the spring of 1995, there were no significant differences in small mammal or herpetofauna collections between burned and control areas. Slope position accounted for more variation among the species of greatest abundance than did burning. Concern for the effects of prescribed fire as a management tool on small mammals and herpetofauna in the southern Appalachians seems unwarranted.
Abstract: We review and compare well-studied examples of five large, infrequent disturbances (LIDs)-fire, hurricanes, tornadoes, volcanic eruptions, and floods-in terms of the physical processes involved, the damage patterns they create in forested landscapes, and the potential impacts of those patterns on subsequent forest development. Our examples include the 1988 Yellowstone fires, the 1938 New England hurricane, the 1985 Tionesta tornado, the 1980 eruption of Mount St. Helens, and the 1993 Mississippi floods. The resulting landscape patterns are strongly controlled by interactions between the specific disturbance, the abiotic environment (especially topography), and the composition and structure of the vegetation at the time of the disturbance. The very different natures of these interactions yield distinctive temporal and spatial patterns and demand that ecologists increase their knowledge of the physical characteristics of disturbance processes. Floods and fires can occur over a long period, whereas volcanic eruptions and wind-driven events often last for no more than a few hours or days. Tornadoes and floods produce linear patterns with sharp edges, but fires, volcanic eruptions, and hurricanes can affect broader areas, often with gradual transitions of disturbance intensity. In all cases, the evidence suggests that LIDs produce enduring legacies of physical and biological structure that influence ecosystem processes for decades or centuries.
Abstract: Logging and wildfire are significant anthropogenic disturbance agents in tropical forests. We compared the abundance and species richness of selected terrestrial wildlife taxa including small mammals, amphibians, reptiles, and terrestrial invertebrates in areas burned by wildfire and then logged and in adjacent undisturbed areas of a tropical humid forest in Bolivia. Disturbed areas had 24% less canopy cover than undisturbed areas but had 2.6 times the cover of large woody debris. Understory cover did not differ between disturbed and undisturbed areas. Small mammal abundance and species richness in disturbed areas were 43 and 70% higher, respectively, than in adjacent undisturbed areas. Herpetofaunal abundance did not differ significantly among disturbed and undisturbed areas, but trends for higher abundance were observed for both reptiles and amphibians in disturbed areas. Herpetofaunal species richness was significantly higher in disturbed compared to undisturbed areas. Total terrestrial invertebrate abundance, as estimated by pitfall traps, was significantly higher in undisturbed compared to disturbed areas mostly due to higher abundances of Formicidae and Blattidae. However, two invertebrate groups, Orthoptera and Lepidoptera (larvae) were more abundant in disturbed areas. Wildlife conservation strategies for areas where logging or wildfire occur should take into account species- or guild-specific responses to these disturbance agents.
Abstract: The short- and long-term post-fire response patterns of small mammals, reptiles and amphibians inhabiting mallee woodlands and heathlands in temperate Australia are reviewed with respect to species' life history parameters in a search for unifying trends. Pyric response patterns of small mammal species are closely tied to their shelter, food and breeding requirements. There is a trend of increased specificity and reduced flexibility in life history traits concomitant with increased impact of fire and later post-fire recolonization. For reptiles there appears to be a strong relationship between the shelter and foraging requirements of species and their abundance in various successional states. The high incidence of burrowing in mallee/heath amphibian fauna imparts considerable resilience to fire, and most species' abundance and distribution patterns seem more closely related to moisture regimes than to fire perse.
The high degree of consistency between species' post-fire response patterns and their life history parameters points to the feasibility of developing a model to predict the impact of fire on small vertebrates. Such a model is currently being developed.
Abstract: Louisiana Seaside Sparrows (Ammodramus maritimus fisheri) breed and winter exclusively in brackish and saline marshes along the northern Gulf of Mexico. Many Gulf Coast marshes, particularly in the Chenier Plain of southwestern Louisiana and southeastern Texas, are burned intentionally in fall or winter as part of waterfowl management programs. Fire reportedly has negatively affected two Seaside Sparrow Subspecies (A. m. nigrescens and A. m. mirabilis) in Florida, but there is no published information regarding effects of fire on A. m. fisheri. We compared abundance of territorial male Louisiana Seaside Sparrows, number of nesting activity indicators, and vegetation structure in paired burned and unburned plots in Chenier Plain marshes in southwestern Louisiana during the 1996 breeding season (April-July) before experimental winter burns (January 1997) and again during two breeding seasons post-burn (1997-1998). We found that abundance of male sparrows decreased in burned plots during the first breeding season post-burn, but was higher than that of unburned plots during the second breeding season post-burn. Indicators of nesting activity showed a similar but non-significant pattern in response to burning. Sparrow abundance and nesting activity seemingly are linked to dead vegetation cover, which was lower in burned plots during the first breeding season post-burn, but did not differ from that in unburned plots during the second breeding season post-burn. We recommend that marsh management plans in the Gulf Coast Chenier Plain integrate waterfowl and Seaside Sparrow management by maintaining a mosaic of burned and unburned marshes and allowing vegetation to recover for at least two growing seasons before reburning a marsh.
Abstract: We examined the effects of chaparral wildfire on stream-breeding California newts (Taricha torosa) in a 750-m stretch of a perennial Santa Monica Mountain stream (Los Angeles County). Detailed field surveys of 1992 and 1993 established the composition (run, riffle, pool) of this habitat and determined oviposition sites of newts. We also quantified California newt egg mass density and estimated density of newt adults. A chaparral wildfire burned the entire study site on 2 November 1993. Using the same methods, we collected field survey data in 1994 and 1996. Erosion following the 1993 wildfire produced major changes in stream morphology and composition. Pools and runs represented approximately 40-50% of pre-fire stream area. In the spring following the fire, the stream consisted of less than 20% run and pool. Pools that did remain were often smaller and shallower. The average density of adult California newts did not differ among years. The total number of newt egg masses in the spring after the fire was approximately one-third of egg mass counts from pre-fire surveys. Most California newt egg masses were laid in pools and runs; California newts prefer deeper slow-moving water. We conclude that fire-induced landslides and siltation have eliminated pools and runs, thus reducing the amount of habitat suitable for oviposition. Habitat alterations caused by fire likely account for the observed reduction of egg masses at the stream.
Abstract: We studied litter-dwelling beetles (Coleoptera: Carabidae and Staphylinidae) in residual patches of unburned forests (fire residuals) left by two natural wildfires in high-elevation coniferous forests in western Alberta, Canada. Fire residuals were wet, late-successional patches of fir and spruce stands, and served as refugia for populations of forest-dwelling beetle species. The largest fire residuals contained older living trees than the mature forest surrounding the burnt areas. Pterostichus empetricola, a glacial relict beetle species, was associated only with habitats provided by the fire residuals. Although there was no relationship between the size of fire residuals and beetle diversity or activity-abundance, more Nebria crassicornis were collected per trap in larger residuals, suggesting dependence of this species on late-seral attributes present within the largest residuals. Conservation of habitats-equivalent to fire residuals in managed forests will likely contribute to landscape continuity and preservation of faunal elements common in wildfire-origin landscapes.
Abstract: Trees may be retained on logged sites in eucalypt forests for a number of reasons, such as to provide wildlife habitat, for future wood production, for aesthetic reasons, to mitigate erosion, or to provide seed for regeneration. These trees may be required to survive for a considerable period to meet these objectives. Logged sites in eucalypt forests are routinely treated with a post-logging slash-burn to reduce fuel loads and facilitate regeneration. We compared rates of mortality and collapse among trees retained on logged sites that were routinely treated with a high-intensity slash-burn with logged sites routinely treated with a low-intensity slash-burn. All observations were made 2-5 years after logging. The proportion of all retained trees that were killed after logging was 37% on sites treated with a high-intensity slash-burn and 14% on sites treated with a low-intensity slash-burn. The rate of collapse among retained trees over the same period was 1.5 and 0.5%, respectively. Results of logistic regression models indicated that trees retained on logged sites were more likely to die and collapse if the site was treated with a high-intensity slash-burn; however, trees were also more likely to die if the basal area of trees retained on the site was relatively low and the site had a northerly aspect. Mortality was similar among all diameter classes on sites treated with a high-intensity slash-burn. Some of the objectives of retaining trees on logged sites, such as perpetuating hollow-bearing trees for wildlife, may be compromised where high-intensity post-logging slash-burns are employed.
Abstract: Because of increasing concern over the constancy of intervals between prescribed fires within a vegetation type, we examine various sources of evidence that can be used to determine variation appropriate to the conservation of biodiversity while minimizing the chances of economically destructive fires. Primary juvenile periods of plants (especially of 'serotinous seeders') and non-breeding periods of birds (especially poorly dispersed species) suggest extreme lower limits for fire intervals whereas longevity of plant species which usually only reproduce after fire, set the extreme upper li:mits. Modelling of the behaviour of selected plant and animal species may be used to set 'optimal' mean intervals. Historical fire-interval data might seem a useful way to determine the variation about the mean fire-interval but data are scarce and interpretations are controversial. The Weibull distribution and its special case, the negative exponential distribution, have been the most supported in North American studies of unplanned fires. It has been argued that fire-interval distributions, before European settlement at least, were largely the result of large fires during, or following, extreme weather events (dry in forests, wet in the arid zone). Long weather records are most beneficial when they can be related to the areas burned each year. Practical solutions to the question 'what range of fire intervals should be used at any one site' may be achieved using highly simplified skewed distributions, constructed on the basis of land-management objectives.
Abstract: This paper reports on the results of a 3-year field study of the effects of spring/summer burning and cattle grazing on wintering sparrows in the grasslands of southeastern Arizona. The effects of fire were studied with 1 year of pre-burn data and 1 year of post-burn data from 1 fire, plus limited sampling from a second fire at Buenos Aires National Wildlife Refuge in Pima County, Ariz, The effects of grazing were studied by comparing study plots at a site that has not been grazed by cattle since 1968 with a nearby grazed pasture in Santa Cruz County, Ar;iz. Sparrow abundance was measured as the number of captures from flushnetting sessions conducted by groups of 13- 30 volunteers. Vesper (Pocecetes gramineus (Gmelin)) and Savannah (Passerculus sandwichensis (Gmelin)) Sparrows responded positively to fire, while Cassin's Sparrows (Aimophila cassinhi (Woodhouse)) responded negatively. The ecologically and geographically restricted Baird's (Ammodramus baridil (Audubon)) and Grasshopper (A. savannarum (Gmelin)) Sparrows utilized burned areas during the first post-burn winter and did not significantly respond to fire. Both Ammodramus sparrows also utilized the grazed pasture; they were more abundant there than in the ungrazed study area in 1 year. While field observations and a prior study suggest that heavy grazing can have a strong detrimental effect on Ammodramus sparrows, the results of this study suggest that moderate cattle grazing may be compatible with the conservation of these species.
Abstract: Fire has an important role in the sensory ecology of many animals. Using acoustic cues to detect approaching fires may give slow-moving animals a head start when fleeing from fires. We report that aestivating juvenile reed frogs (Hyperolius nitidulus) respond to playbacks of the sound of fire by fleeing in the direction of protective cover, where they are safe. This is a novel response to fire not known to occur in other animals. Moreover, we identify the rapid rise-time of the crackling sound of fire as the probable cue used. These results suggest that amphibian hearing not only has evolved through sexual selection, but also must be viewed in a broader context.
Abstract: We tested whether the herpetofaunal response to clearcutting followed by site preparation was similar to high-intensity wildfire followed by salvage-logging in sand-pine scrub. Herpetofaunal communities were compared in three replicated 5- to 7-year post-disturbance treatments and mature sand-pine forest. The three disturbance treatments were (1) high-intensity wildfire, salvage-logging, and natural regeneration; (2) clearcutting, roller-chopping, and broadcast-seeding; and (3) clearcutting and bracke-seeding. Animals were trapped over a 14-month period using pitfall traps with drift-fences. Micro-habitat features were measured along line transects. Because amphibian (frog) occurrence appeared to be unaffected by treatment, this paper focuses only on reptile communities. Six species of lizards and one snake species were numerically dominant. Reptile species richness, diversity, and evenness did not differ among treatments or mature forest. Species composition differed markedly, however, between mature forest and disturbance treatments. Typical open scrub species such as Cnemidophorus sexlineaus, Sceloporus woodi, and Eumeces egregius, were dominant in high-intensity burn, roller-chopped, and bracke-seeded stands but scarce in mature forests, and they were positively correlated with bare sand and other micro-habitat features typical of open scrub. Conversely, Eumeces inexpectatus was most abundant in mature forests and was correlated with ground litter and other features typical of mature forest. With respect to the species sampled, especially the lizards (including endemic species) of open scrub, clearcutting appeared to mimmic high-intensity wildfire followed by salvage-logging by creating microhabitat features such as bare sand. In a mirror image of the usual concept, forest maturation historically served as the fragmenting agent of an extensive open-scrub landscape matrix that was maintained by high-intensity wildfire. Hence, the patchwork of age classes created by current clearcutting patterns could serve as a barrier to lizard dispersal and impede meta-population dynamics. The absence of a true control (unsalvaged burns) suggests caution in interpreting the results of this study.
Abstract: A population of frillneck lizards, Chlamydosarus kingii, was monitored by radio telemetry and mark-recapture techniques between April 1991 and April 1994, as part of a landscape-scale fire experiment, in Kakadu National Park, Northern Territory. The study aimed to investigate both the short- and longer-term effects of fire on a lizard species in a tropical savanna where fires are frequent and often annual. Frillneck lizards are able to survive fires that occur in the first few months of the dry season by remaining perched in trees. A high level of mortality (29%) occurred during late dry-season fires, along with changes in their behavioural response to fire; sheltering in either larger trees or hollow termite mounds. Food is more accessible after fires due to the removal of ground vegetation. This is reflected in greater volume and diversity of prey in stomach contents after fires. This increase is more pronounced after late dry-season fires, possibly due to increased accessibility of prey caused by more complete vegetation removal. Frillneck lizards show an overall preference for trees with a dense canopy cover located in an area with a low density of grass. Fire has an effect on this relationship. Frillneck lizards in habitat unburnt for a number of years tend to perch in trees with a smaller canopy. Volume and composition of lizard stomach contents was broadly similar among fire treatments over a 2-year period, although termites were more predominant in stomach contents of lizards in unburnt habitat. Wet-season body condition is lower in lizards from unburnt habitat, although the reason for this is unclear. These results demonstrate the importance of different fire intensities and regimes on the ecology of a lizard species in a tropical savanna.
Abstract: The impact of fire and mechanical habitat destruction on a population of the tortoise Testudo hermanni in northern Greece varied with vegetation type and season. A major fire in summer 1980 caused low (< 5%) mortality of sexable tortoises (> 10 cm) in coastal heath, highest (about 50%) mortality in grassland, and intermediate levels in dry heath. Mechanical habitat destruction caused about 50% mortality in affected areas. Mortality of juveniles was greater than that of sexable animals. Overall, the 1980 catastrophe was more damaging than previously thought, causing a 64% decrease in the total size of the Alyki main heath population. A localized summer fire in 1986 caused a similar level and pattern of mortality to that of 1980, but a spring fire in 1988 had little effect on the tortoise population. A fire and mechanical habitat destruction in winter 1989/90 caused only a 14% decrease in population size; mortality was again concentrated in grassland areas, but affected juveniles and sexable animals equally. Variation of mortality with season suggests that any burning needed for habitat management at tortoise sites should occur in winter or early spring. Juveniles were undersampled by 3-4 times compared to sexable animals; their number increased greatly by 1990, reaching the same proportion as in the original population. There was, however, no recovery in the number of sexable tortoises in the decade after the 1980 catastrophe.
Abstract: Five tetra- to hexabrominated diphenyl ether (BDE) congeners (BDE-47, -99, -100, -153 and -154) are the most frequently reported in wildlife and humans. The commercial penta-BDE product, used predominantly to flame-retard polyurethane foam, consists primarily of these same congeners. In 1999, North American demand accounted for 98% of the total global penta-market of 8500 metric tons. Frogs, housed with flame retardant-treated polyurethane foam as a dry substrate, accumulated 10,100 mug/kg (wet weight) of the above BDEs. Crickets kept therein as food contained 14,400 mug/kg. The crickets are believed to have browsed directly on the foam and, in turn, were consumed by the frogs. BDE congener composition in all three matrices matched that of the penta-commercial product. Similar congeners were also observed in soil and stream sediments collected near a polyurethane foam manufacturing plant. Summed concentrations of BDE-47, -99 and -100, the dominant congeners observed in these samples, ranged from <1 to 132 mug/kg (dry weight basis). Sunfish fillets obtained from a nearby, off-site pond contained a total of 624 mug/kg (lipid basis). Sewage treatment plant (STP) sludge exhibited these same congeners at 1370 mug/kg (dry weight). BDE-209, the fully brominated congener predominant in the commercial deca-BDE product, was also present at 1470 mug/kg. While no known polyurethane foam manufacturers discharged to this plant, the distribution pattern of the low brominated congeners in the sludge matched that of the penta-product. After four weeks of exposure to ambient outdoor conditions, the surface of flame-retarded polyurethane foam became brittle and began to disintegrate. Subsequent dispersal of these penta-containing foam fragments may be one mechanism by which these BDEs reach the environment.
Abstract: We assessed the relative contributions of in situ survival and recolonization to overall recovery of arthropod populations following prescribed fire by monitoring arthropod morphospecies richness and abundance in enclosed and open plots in adjacent burned and unburned units within two remnant Illinois prairies. Vacuum sampling of arthropods at semimonthly intervals following spring burns at each site indicated that fire strongly depressed arthropod abundance initially, but that abundance and species richness tended to recover toward the end of the summer, mostly due to recolonization from adjacent unburned refuges. Nevertheless, arthropod groups (taxa or guilds) were affected differently by fire, and differences in arthropod species composition among burned and unburned plots persisted. Sampled arthropod groups significantly reduced by fire at one or both study sites included springtails (Collembola), deltocephaline leafhoppers (Homoptera: Cicadellidae: Deltocephalinae), aphids (Homoptera: Aphididae), delphacid planthoppers (Homoptera: Delphacidae), parasitoid wasps (Hymenoptera), and spiders (Araneae). Only one group, typhlocybine leafhoppers (Homoptera: Cicadellidae: Typhlocybinae), exhibited a significant positive response to fire. These results indicate that in situ populations of many arthropod species are substantially reduced by prescribed fire. Thus, to preserve native arthropod faunas, land managers should ensure that unburned refuges are maintained and that the intervals between burns are sufficient to allow recolonization of burned areas to occur.
Abstract: The effects of post-fire changes in vegetation and habitat quality on the developmental stability of individual birds have not been assessed to date. Here we compare fluctuating asymmetry in tail feathers of Sardinian Warblers Sylvia melanocephala inhabiting two shrubby zones, the first burned in both 1982 and 1994 and the second only in 1982. Juveniles with unmoulted rectrices showed significantly higher levels of tail feather asymmetry in the zone burned in 1994. This result is consistent with the hypothesis that recently burned shrublands offer lower quality habitats for this species. Because feather asymmetry was positively and significantly related to the abundance of low shrubs up to 50 cm tall, we suggest that juvenile assessment of habitat quality is primarily based on the structure of the shrub layer.
Abstract: A current paradigm in conservation biology is that forest harvest practices that better approximate natural disturbance processes are more likely to conserve biodiversity. We contrasted bird communities in three replicate stands in each of 1, 13-15, and 22-28 yr old forests following wildfire and harvest in north-central Alberta, Canada. Stands were chosen from old (>120 yr) boreal mixedwood forests having greater than or equal to 95% of the canopy trees killed during fire, and harvested sites retaining an average of 6% of the pre-harvest canopy trees. For all age classes, postharvest sites tended to have greater bird abundance. Species composition also differed between these treatment types. Two-Way Indicator Species Analysis (TWINSPAN) identified five major ecological groupings of species that differed between wildfire and harvest, and among stand ages. Correspondence analysis (CA) identified similar bird communities. Greatest differences between bird communities occurred immediately following disturbance, and gradual convergence of communities occurred throughout the first 28 yr after disturbance. Species associated with open shrub and grassland or riparian habitats were associated primarily with I-yr postharvest stands. Three-toed Woodpeckers (Picoides tridactyla) and Black-backed Woodpeckers (P. arcticus), together with other species that use snags for foraging or nesting, occurred primarily in 1-yr postwildfire stands. Convergence in avian communities was correlated with the loss of standing snags on postwildfire sites. However, differences in bird communities were apparent up to 28 yr following disturbance, and this lack of complete convergence has important consequences for sustainable forestry practices designed to maintain biodiversity in the boreal mixedwood forest. Notably, Connecticut Warbler (Oporornis agilis), Brown Creeper (Certhia americana), Winter Wren (Troglodytes troglodytes), and American Robin (Turdus migratorius) had higher densities on postwildfire than on postharvest stands. Lincoln's Sparrow (Melospiza georgiana), Alder Flycatcher (Empidonax alnorum), Tennessee Warbler (Vermivora peregrina), Black-and-white Warbler (Mniotilta varia), American Redstart (Setophaga rutticilla), Mourning Warbler (Oporornis philadelphia), Rose-breasted Grosbeak (Pheucticus ludoviciana), Canada Warbler (Wilsonia canadensis), and Pine Siskin (Carduelis pinus) had higher densities on postharvest stands, possibly due to the greater abundance, after harvest, of larger live residual trees and a taller and more dense shrub layer. Harvest designed to approximate stand-replacing fires may require the retention of more snags than is currently practiced. New approaches to fire salvage logging are also required to ensure adequate retention of standing dead trees on the landscape.
Abstract: Information on wildlife survival of prescribed (controlled) brushland fires was obtained by three methods: (1) 37 rodents and snakes in cages with temperature recording devices were placed in different habitat situations, and the area was control burned; (2) the number of birds and mammals drinking from a spring was counted both before and after the area was burned; and (3) the behavior of wild animals was observed from an observation point within the fire.
The cage temperature lethal to rodents was somewhere between 138o and 145o F. Results indicate that there was little chance of wild vertebrate animals getting caught in a situation that would lead to their death during such fires. Most species of vertebrates benefit from control burns, because the habitat then becomes more favorable.
Abstract: Effects of fire, forest insects and diseases, grazing, and forest health treatments on fish populations and habitat are reviewed. Fire, insects, and disease affect fish habitat by their influence on the rate and volume of woody debris recruitment to streams, canopy cover and water temperature, stream flow, channel erosion, sedimentation, nutrients, and residual vegetation. Physical effects from fire vary greatly depending on fire severity and extent, geology, soil, topography, and orientation of the site, and subsequent precipitation. Most effects moderate within a decade. Post-fire erosion and wood recruitment are also influenced by fire lines, road construction, and timber harvest. Although some disturbances, such as severe fire and subsequent floods, appear catastrophic, and effects may last decades or centuries, natural disturbances help create and maintain diverse, productive aquatic habitats. Recolonization of fish populations following wildfires can be rapid and is related to occurrence of local refugia, life history patterns, access for migratory forms, and distribution of the species. In most livestock studies, grazing negatively affected fish habitat and populations, but results may vary depending on sites and specific grazing management. Effective approaches to grazing management similarly depend on the specific application and the commitment of operators and managers. Restoration of the structure, function, and processes of watersheds more similar to those with which native species evolved may favor those species; however, there is little documentation of the aquatic effects of those activities. Risk from vegetative treatments may be minimized by experimenting outside of critical areas (i.e., conserving key habitats and populations, focusing intensive treatments on upland sites). Use of more benign techniques (e.g., lower-impact logging systems) and pulsed treatments consistent with characteristics of natural disturbance regimes are other considerations for achieving both terrestrial and aquatic objectives.
Abstract: Fire-induced soil hydrophobicity is presumed to be a primary cause of the observed post-fire increases in runoff and erosion from forested watersheds in the Colorado Front Range, but the presence and persistence of hydrophobic conditions has not been rigorously evaluated. Hence the goals of this study were to: (1) assess natural and fire-induced soil hydrophobicity in the Colorado Front Range, and (2) determine the effect of burn severity, soil texture, vegetation type, soil moisture, and time since burning on soil hydrophobicity.
Five wild and prescribed fires ranging in age from 0 to 22 months were studied. Each fire had four study sites in ponderosa pine forest, that had been burned at high, moderate, or low severity, and three sites were in unburned areas. Additional sites were established in lodgepole pine stands and an area with unusually coarse-textured soils. At each site the soil hydrophobicity was assessed in two pits using the water drop penetration time (WDPT) and the critical surface tension (CST). Measurements were made at the mineral soil surface and depths of 3, 6, 9, 12, 15, and 18 cm.
In sites burned at moderate or high severity the soils were often strongly hydrophobic at 0. 3, and 6 cm. Unburned sites or sites burned at low severity were typically hydrophobic only at the surface. Although soil hydrophobicity generally strengthened with increasing burn severity, statistically significant differences in soil hydrophobicity were difficult to detect because of the high variability within and between sites. Hydrophobicity also increased with increasing percent sand and was not present when soil moistures exceeded 12-25%. There were no significant differences in soil hydrophobicity between ponderosa and lodgepole pine stands, regardless of burn severity.
Repeat measurements on one fire suggest a weakening of fire-induced soil hydrophobicity after 3 months. Comparisons between fires suggest that fire-induced soil hydrophobicity persists for at least 22 months. Overall, CST values were more consistent and more highly correlated with the independent variables than the WDPT, and the CST is recommended for assessing soil hydrophobicity rather than the more commonly used WDPT.
Abstract: During the two breeding seasons immediately following the numerous and widespread fires of 1988, I estimated bird community composition in each of 34 burned-forest sites in western Montana and northern Wyoming. I detected an average of 45 species per site and a total of 87 species in the sites combined.
Abstract: Previous to this study, the Pine Barrens treefrog, Hyla andersonii, was known to occur at ten localities within Conecuh National Forest. During this study, the status of this frog species in the Forest was assessed from June through September 1991. Location of the frogs was accomplished by searching for suitable habitats by day, revisiting the sites at night, and listening for the distinct call of males or eliciting them to call by vocally imitating their call. Thirteen new localities were discovered and six previous localities maintained calling males. At four previously known localities males were never heard, indicating that they no longer support Hyla andersonii. Lack of fire at these four localities is suspected to be the reason the frog populations have disappeared.
Abstract: The Boreal Mixedwood Ecosystem Study near Thunder Bay, Ontario is a multi-disciplinary investigation of the impacts of harvesting and fire on the structure and function of a boreal mixedwood ecosystem. The fire component comprises a set of treatments in which fire severity was manipulated by adjusting fuel loadings through a variety of harvesting techniques, and also included fire in standing timber. Intensive fuel sampling before and after the fire enabled detailed determinations of fuel consumption, heat output and forest floor reduction. Nutrient concentrations in ash, soil, and plant tissue following the fire were compared with fire severity in order to quantify potential nutrient inputs and their relationship to the amount of biomass consumed during the fire. Forest floor and woody fuel consumption varied significantly among treatments, with the most important factor being whether or not the stand had been harvested previous to the fire. The pH was highest and P concentrations among the lowest in the ash of unharvested blocks. Nutrient concentrat