Spatial Scale and Shape of Prescribed Fires Influence Use by Wild Turkeys

In recent years, there have been increasing efforts to understand effects of prescribed fire on population dynamics of wild turkeys (Meleagris gallopavo; turkeys) in pine (Pinus spp.) forests. Although distribution of turkeys is not limited to pine forests, these forests provide nesting and brood-rearing habitat throughout the southeastern United States. Previous studies have investigated direct (e.g., nest loss to fire) and indirect (e.g., nest- and brood-site selection) effects of prescribed fire, but little is known about how turkeys are influenced by the spatial scale and shape of prescribed fire. We constructed an individual-based model (IBM) with landscapes of 2 burn unit shapes and 17 spatial scales. We used telemetry data obtained from global positioning system-marked female turkeys to replicate movement behaviors of turkeys within the model. We hypothesized that use of units burned during the current year (<1 yr) would decrease as scale of fires increased, and that shape of burn units would influence use by turkeys. Spatial scale most influenced turkey use; the greatest use was in burned stands of approximately 23 ha in size, whereas least use was associated with burned stands >1,269 ha. At a spatial scale of 23 ha, the daily percent use of rectangular burn units was 7% greater than square-shaped burn units. Likewise, daily percent use of rectangular burn units was 34% greater than square-shaped burn units at a spatial scale of 1,269 ha. When burn units were rectangular-shaped, daily percent use decreased by 48% as the spatial extent of the fires increased from 23 ha to 203 ha. Likewise, when burn units were square-shaped, turkey use decreased by 49% as spatial extent of fires increased from 23 ha to 203 ha. Our findings suggest the importance of managing forested landscapes with prescribed fires not exceeding approximately 200 ha if wild turkeys are a management concern. © 2020 The Wildlife Society.     

Evening Bat Summer Roost-Site Selection on a Managed Pine Landscape

ABSTRACT Creation and maintenance of forested corridors to increase landscape heterogeneity has been practiced for decades but is a new concept in intensively managed southern pine (Pinus spp.) forests. Additionally, more information is needed on bat ecology within such forest systems. Therefore, we examined summer roost-site selection by evening bats (Nycticeius humeralis) in an intensively managed landscape with forested corridors in southeastern South Carolina, USA, 2003–2006. We radiotracked 53 (26 M, 27 F) adult evening bats to 75 (31 M, 44 F) diurnal roosts. We modeled landscape-level roost-site selection with logistic regression and evaluated models using Akaike's Information Criterion for small samples. Model selection results indicated that mature (≥40 yr) mixed pine-hardwood stands were important roost sites for male and lactating female evening bats. Upland forested corridors, comprised of mature pine or mixed pine-hardwoods, were important roosting habitats for males and, to a lesser extent, lactating females. Male roosts were farther from open stands and lactating female roosts were farther from mid-rotation stands than randomly selected structures. Our results suggest roost structures (i.e., large trees and snags) in mature forests are important habitat components for evening bats. We recommend maintaining older (>40 yr old) stand conditions in the form of forest stands or corridors across managed landscapes to provide roosting habitat. Furthermore, our results suggest that an understanding of sex-specific roost-site selection is critical for developing comprehensive guidelines for creating and maintaining habitat features beneficial to forest bats.     

Effects of Understory Vegetation Management on Brood Habitat for Northern Bobwhites

Abstract: Northern bobwhite (Colinus virginianus) populations have experienced severe declines for several decades, and declines have been particularly precipitous in the southern United States. These declines are partially attributable to large-scale conversions of potential habitat to short-rotation pine (Pinus spp.) forests managed for wood fiber production and fire exclusion in pine-dominated landscapes. We used standard arthropod sampling techniques, human-imprinted bobwhite chicks, and vegetation response to evaluate effects of different understory vegetation management practices on brood habitat quality within a commercially managed pine forest in Louisiana, USA, during 2002–2005. Specifically, we evaluated effects of mowing, prescribed fire during the growing season, prescribed fire in combination with imazapyr application, and no vegetation management on arthropod abundance and diversity, vegetation response, and the probability of bobwhite chicks successfully capturing an arthropod. Bobwhite chicks were more successful at capturing arthropods, and arthropod abundance and diversity were greatest, in plant communities managed using prescribed fire and imazapyr. Forest stands managed using a combination of fire and imazapyr were managed primarily to benefit the federally endangered red-cockaded woodpecker (Picoides borealis; RCW). Our findings suggest that management directed toward improving forest condition for RCWs improves habitat quality for brooding bobwhites. However, bobwhite chicks in our study area were less successful at capturing arthropods than were chicks in other studies in the southeastern United States. Brood-rearing habitat in pine forests similar to those we studied may be of generally poor quality, and could be related to precipitous declines of bobwhites in the West Gulf Coastal Plain. Managers should recognize that creating high-quality brood habitat in forests similar to those we studied will require more intensive management of understory vegetation than we studied.     

Use of Forest Edges by Bats in a Managed Pine Forest Landscape

ABSTRACT Forest edges often have increased species richness and abundance (edge effect) and affect spatial behaviors of species and dynamics of species interactions. Landscapes of intensively managed pine (Pinus spp.) stands are characterized by a mosaic of patches and linear forest edges. Managed pine forests are a primary landscape feature of the southeastern United States, but the effects of intensive management on bat communities are poorly understood. Insectivorous bats are important top predators in nocturnal forest food webs. We examined bat foraging behavior along forest edges and in 4 structurally distinct stand types (open-canopy pine, prethinned pine, thinned pine, and unmanaged forest) within a managed pine forest in the coastal plain of North Carolina, USA. During May-August, 2006 and 2007, we recorded echolocation calls using Pettersson D240X bat detectors linked to digital recorders at 156 sites. We also sampled nocturnal flying insects at each site using Malaise insect traps. We used negative binomial count regression models to describe bat foraging behavior relative to forest edges, stand types, and prey availability. Although some species showed affinities for certain stand types and prey items, bat activity patterns were most strongly related to forest edges. Edges were used extensively by 6 aerial-hunting bat species, but avoided by Myotis species. Forest edges function similarly to natural forest gaps, by providing foraging opportunities for aerial-hunting bat species. Therefore, the maintenance of forest edges in managed pine landscapes may enhance foraging habitat for aerial-hunting bat species.     

Wild Turkey Nest Success in Pine-Dominated Forests of the Southeastern United States

Nest success is a primary component of productivity for wild turkeys (Meleagris gallopavo; turkeys) and there is concern that turkey productivity is declining across the southeastern United States. We evaluated the influence of nest site and landscape characteristics on risk of nest failure for turkeys in pine (Pinus spp.)-dominated forests across the southeastern United States. We used Cox proportional hazard models to evaluate daily hazard of nest failure associated with nest site and landscape metrics within 500-m and 1-km buffers centered on nests. Of 451 nests monitored (n = 320 females) between 2014 and 2018, 76% failed, with predation as the primary cause. Daily hazard of nest failure increased by 1.2% for each day that females delayed nest incubation following the mean nesting date (29 Apr; β_day = 0.010 ± 0.002 [SE]; hazard ratio [HR] = 1.01, 95% CI = 1.006–1.015). Environmental covariates associated with risk of nest failure included the maximum enhanced vegetation index (EVI) and distance to the nearest ecotone. Daily hazard increased with increasing distance away from an ecotone (β_ecotone = 0.16 ± 0.06; HR = 1.17, CI = 1.03–1.32) and with lower EVI around the nest (β_EVI = −0.30 ± 0.06; HR = 0.74, CI = 0.65–0.83). Additional nest site or landscape covariates were included in competitive models but did not influence risk of nest failure significantly. Our study highlights the importance of considering landscape context when designing and implementing land management actions intended to enhance wild turkey reproduction. Our findings suggest that landscape metrics thought to be important to turkeys in northern agro-forested landscapes may not be relevant to turkeys in pine ecosystems of the southeastern United States. © 2021 The Wildlife Society.     

Female Moose Prioritize Forage Over Mortality Risk in Harvested Landscapes

Since 2010, several moose (Alces alces) populations have declined across North America. These declines are believed to be broadly related to climate and landscape change. At the western reaches of moose continental range, in the interior of British Columbia, Canada, wildlife managers have reported widespread declines of moose populations. Disturbances to forests from a mountain pine beetle (Dendroctonum ponderosae) outbreak and associated salvage logging infrastructure in British Columbia are suspected as a mechanism manifested in moose behavior and habitat selection. We examined seasonal differences in moose habitat selection in response to landscape change from mountain pine beetle salvage logging infrastructure: dense road networks and large intensive forest harvest cutblocks. We used 157,447 global positioning system locations from 83 adult female moose from 2012 to 2016 on the Bonaparte Plateau at the southern edge of the Interior Plateau of central British Columbia to test whether increased forage availability, landscape features associated with increased mortality risk, or the cumulative effects of salvage logging best explain female moose distribution using resource selection functions in an information-theoretic framework. We tested these hypotheses across biological seasons, defined using a cluster analysis framework. The cumulative effects of forage availability and risk best predicted resource selection of female moose in all seasons; however, the covariates included in the cumulative models varied between seasons. The top forage availability model better explained moose habitat use than the top risk model in all seasons, except for the calving and fall seasons where the top risk model (distance to road) better predicted moose space use. Selection of habitat that provides forage in winter, spring, and summer suggests that moose seasonally trade predation risk for the benefits of foraging in early seral vegetation communities in highly disturbed landscapes. Our results identified the need for intensive landscape-scale management to stem moose population declines. Additional research is needed on predator densities, space use, and calf survival in relation to salvage logging infrastructure. © 2020 The Wildlife Society.     

Importance of semi-natural habitats for the conservation of butterfly communities in landscapes dominated by pine plantations

While the area of plantation forests continues to increase worldwide, their contribution to the conservation of biodiversity is still controversial. There is a particular concern on the central role played by natural habitat remnants embedded within the plantation matrix in conserving species-rich insect communities. We surveyed butterflies in maritime pine plantation landscapes in south-western France in 83 plots belonging to seven habitat types (five successional stages of pine stands, native deciduous woodlands and herbaceous firebreaks). The effect of plot, habitat and landscape attributes on butterfly species richness, community composition and individual species were analysed with a General Linear Model (GLM), partial Canonical Correspondence Analysis (CCA) and the IndVal method. The most important factors determining butterfly diversity and community composition were the presence of semi-natural habitats (deciduous woodlands and firebreaks) at the landscape scale and the composition of understorey vegetation at the plot scale. Pure effects of plot variables explained the largest part of community variation (12.8%), but landscape factors explained an additional, independent part (6.7%). Firebreaks were characterized by a higher species richness and both firebreaks and deciduous woodlands harboured species not or rarely found in pine stands. Despite the forest-dominated landscape, typical forest butterflies were rare and mainly found in the deciduous woodlands. Threatened species, such as Coenonympha oedippus and Euphydryas aurinia, were found in pine stands and in firebreaks, but were more abundant in the latter. In the studied plantation forest, the conservation of butterflies depends mainly on the preservation of semi-natural habitats, an adequate understorey management and the maintenance of soil moisture levels.     

Marten space use and habitat selection in managed coniferous boreal forests of eastern Canada

Effects of habitat loss and fragmentation on the behavior of individual organisms may have direct consequences on population viability in altered forest ecosystems. The American marten (Martes americana) is a forest specialist considered as one of the most sensitive species to human-induced disturbances. As some studies have shown that martens cannot tolerate >30–40% clear-cuts within their home range, we investigated marten space use (home range size and overlap) and habitat selection in landscapes fragmented by 2 different patterns of timber harvesting in the black spruce boreal forest: dispersed-cut landscapes (10–80 ha cut-blocks) and clustered-cut landscapes (50–200 ha cut-blocks). We installed radio-collars on female martens and determined 20 winter home ranges (100% minimum convex polygons and 60–90% kernels) in dispersed-cut (n = 8) and clustered-cut (n = 12) landscapes. Home range size was not related to the proportion of clear-cuts (i.e., habitat loss), but rather to the proportion of mixedwood stands 70–120 years old. However, female body condition was correlated to habitat condition inside their home ranges (i.e., amount of residual forest and recent clear-cuts). At the home range scale, we determined that mixedwood forests were also among the most used forest stands and the least used were recent clear-cuts and forested bogs, using resource selection functions. At the landscape scale, home ranges included more mixedwood forests than random polygons and marten high activity zones were composed of more residual forest and less human-induced disturbances (clear-cuts, edges, and roads). These results suggest that mixedwood forests, which occupy approximately 10% of the study area, play a critical role for martens in this conifer-dominated boreal landscape. We recommend permanent retention or special management considerations for these isolated stands, as harvesting mixedwood often leads to forest composition conversion that would reduce the availability of this highly used habitat. © The Wildlife Society, 2013     

Linking alternative food sources to winter habitat selection of herbivores in overbrowsed landscapes

During winter, ungulates in boreal forests must cope with high energetic costs related to locomotion in deep snow and reduced forage abundance and quality. At high density, ungulates face additional constraints, because heavy browsing reduces availability of woody browse, the main source of forage during winter. Under these severe conditions, large herbivores might forage on alternative food sources likely independent of browsing pressure, such as litterfall or windblown trees. We investigated the influence of alternative food sources on winter habitat selection, by studying female white-tailed deer (Odocoileus virginianus) living in 2 landscapes with contrasted browse abundance, recently logged and regenerated landscapes, in a population at high density and on a large island free of predators. We fitted 21 female white-tailed deer with Global Positioning System (GPS) collars and delineated winter home ranges and core areas. We measured snow conditions in different habitat categories and sampled vegetation in the core areas and in the rest of the home ranges to determine how forage abundance, protective cover, and snow conditions influenced habitat selection within the home range. In both landscapes, deer were less likely to use open habitat categories as snow accumulated on the ground. At a finer scale, deer inhabiting the regenerated landscape intensively used areas where balsam fir cover was intermediate with greater balsam fir browse density than in the rest of the home range. In the recently logged landscape, deer were more likely to be found near edges between clear-cuts and balsam fir stands and in areas where windblown balsam fir trees were present; the latter being the most influential variable. Although balsam fir browse was sparse and mainly out of reach in this landscape, deer increased the use of areas where it was present. Our results offer novel insights into the resource selection processes of northern ungulates, as we showed that access to winter forage, such as woody browse and alternative food sources, depends on climatic conditions and stochastic events, such as abundant compacted snow or windthrows. To compensate for these scarce and unpredictable food supplies, deer selected habitat categories, but mostly areas within those habitat categories, where the likelihood of finding browse, litterfall, and windblown trees was greatest. © 2011 The Wildlife Society.     

Deer Carrying Capacity in Mid-Rotation Pine Plantations of Mississippi

ABSTRACT Herbicides, commonly used for vegetation management in intensively managed pine (Pinus spp.) forests of the southeastern United States, with and without fire, may alter availability of quality forage for white-tailed deer (Odocoileus virginianus; deer), an economically and socially important game species in North America. Because greater forage quality yields greater deer growth and productivity and intensively managed pine forests are common in the southeastern United States, forest managers would benefit from an understanding of fire and herbicide effects on forage availability to improve habitat conditions for deer. Therefore, we evaluated independent and combined effects of fire and herbicide (i.e., imazapyr) on forage biomass and deer nutritional carrying capacity (CC) on land owned and managed by Weyerhaeuser NR Company in east-central Mississippi, USA. We used a randomized complete block design of 6 pine plantations (blocks) divided into 4 10-ha treatment plots to each of which we randomly assigned a treatment (burn-only, herbicide-only, burn + herbicide, and control). We estimated biomass (kg/ha) of moderate- and high-use deer forage plants during July of 1999–2008, then estimated CC for diets to support either body maintenance (6% crude protein) or lactation (14% crude protein) with a nutritional constraints model. Herbaceous forages responded positively to fire and herbicide application. In most years, CC estimates for maintenance and lactation were greater in burn + herbicide than in controls. Maintenance-level CC was always greater in burn + herbicide than in controls, except at 1 year posttreatment. Burn + herbicide was 2.6–8.3 times greater (x̄ = 4.0) than control for lactation-level CC in 8 of 9 years posttreatment. We recommend fire and selective herbicides to increase high-quality deer forage in mid-rotation, intensively managed pine plantations.     

Evaluating management risks using landscape trajectory analysis: A case study of California fisher

Ecosystem management requires an understanding of how landscapes vary in space and time, how this variation can be affected by management decisions or stochastic events, and the potential consequences for species. Landscape trajectory analysis, coupled with a basic knowledge of species habitat selection, offers a straightforward approach to ecological risk analysis and can be used to project the effects of management decisions on species of concern. The fisher (Martes pennanti) occurs primarily in late-successional forests which, in the Sierra Nevada mountains, are susceptible to high-intensity wildfire. Understanding the effects of fuels treatments and fire on the distribution of fisher habitat is a critical conservation concern. We assumed that the more a treated landscape resembled occupied female fisher home ranges, the more likely it was to be occupied by a female and therefore the lower the risk to the population. Thus, we characterized important vegetation attributes within the home ranges of 16 female fishers and used the distribution of these attributes as a baseline against which the effects of forest management options could be compared. We used principal components analysis to identify the major axes defining occupied female fisher home ranges and these, in addition to select univariate metrics, became our reference for evaluating the effects of landscape change. We demonstrated the approach at two management units on the Sierra National Forest by simulating the effects of both no action and forest thinning, with and without an unplanned fire, on vegetation characteristics over a 45-yr period. Under the no action scenario, landscapes remained similar to reference conditions for approximately 30-yr until forest succession resulted in a loss of landscape heterogeneity. Comparatively, fuel treatment resulted in the reduction of certain forest elements below those found in female fisher home ranges yet little overall change in habitat suitability. Adding a wildfire to both scenarios resulted in divergence from reference conditions, though in the no action scenario the divergence was 4× greater and the landscape did not recover within the 45-yr timeframe. These examples demonstrate that combining the results of forest growth and disturbance modeling with habitat selection data may be used to quantify the potential effects of vegetation management activities on wildlife habitat. © 2011 The Wildlife Society.     

Male Seminole Bat Winter Roost-Site Selection in a Managed Forest

Abstract: Understanding year-round roost-site selection is essential for managing forest bat populations. From January to March, 2004 to 2006, we used radiotelemetry to investigate winter roost-site selection by Seminole bats (Lasiurus seminolus) on an intensively managed landscape with forested corridors in southeastern South Carolina, USA. We modeled roost-site selection with logistic regression and used Akaike's Information Criterion for small samples (AIC_c) and Akaike weights to select models relating roost-site selection to plot- and landscape-level variables. We tracked 20 adult male bats to 71 individual roosts. Bats used a variety of roosting structures, including the canopy of overstory trees, understory vegetation, pine (Pinus spp.) needle clusters, and leaf litter. Roost height, structure type, and habitat type were influenced by changes in minimum nightly temperature. On warmer nights, bats selected taller trees in mature forest stands, but when minimum nightly temperatures were <4° C, bats typically were found roosting on or near the forest floor in mid-rotation stands. We recommend avoiding prescribed burning in mid-rotation stands on days when the previous night's temperature is <4 °C to minimize potential disturbance and direct mortality of bats roosting on or near the forest floor. We encourage forest managers to incorporate seasonal changes in roost-site selection to create year-round management strategies for forest bats in managed landscapes.     

Landscape Use by Hairy Woodpeckers in Managed Forests of Northwestern Washington

ABSTRACT The hairy woodpecker (Picoides villosus) is a keystone species in forest ecosystems of Washington, USA, providing nesting and roosting cavities for many species of wildlife. Therefore, management practices that promote healthy populations of this bird will help to conserve cavity-nesting communities as a whole. The objective of this study was to determine patterns in forest type and landscape use by hairy woodpeckers, and thus, provide landscape-level recommendations to forest managers. We documented the ranging patterns and habitat use of 23 hairy woodpeckers on the Olympic Peninsula using radiotelemetry and a Geographic Information System analysis. Use patterns of stand age, type, and size, as well as distance-from-edge analyses revealed that the hairy woodpecker is a relative generalist in its use of the managed forest landscape. However, certain features, such as older stands with large trees, were used more heavily by nesting pairs. Hairy woodpeckers used 61–80-year forest stands significantly (P < 0.05) more than expected relative to their availability within the birds' home ranges. We also documented significant underuse of 6–10-year and 11–20-year stands, whereas the birds used 41–60-year stands, >80-year stands, and clear-cuts (< 5 yr) equivalent to their availability. We suggest that hairy woodpeckers select older stands with larger, dying trees for foraging, but also use clear-cuts proportionally due to the residual snags, decaying trees, and remnant dead wood available. Higher use (P < 0.001) by hairy woodpeckers of small forest patches (0–5 ha) and intermediate-sized stands (5–30 ha) than large patches (>30 ha) may be a result of the older, higher-quality habitat available in small stands in the managed forest landscape. We recommend that land managers interested in maintaining healthy managed forest ecosystems with a full complement of cavity-using species in forests of western Washington and northwestern Oregon maintain a landscape mosaic with approximately 45% of the landscape in stands >40 years, and >30% of the landscape in stands >60 years.     

Forest Stand Characteristics Altered by Restoration Affect Western Bluebird Habitat Quality

Forest managers are setting Ponderosa pine (Pinus ponderosa) forests in the southwestern United States on a trajectory toward a restored ecosystem by reducing tree densities and managing with prescribed fire. The process of restoration dramatically alters forest stands, and the effects of these changes on wildlife remain unclear. Our research evaluated which aspects of habitat alteration from restoration treatments may be affecting the habitat quality of Western Bluebird (Sialia mexicana), an insectivorous songbird whose populations are declining. Habitat loss resulting from fire‐suppression activities may be partially responsible for their population declines; thus, the bluebird is a good representative species for assessing how the reconstruction of presuppression forest conditions can affect wildlife. We measured habitat variables at 63 successful and 19 unsuccessful Western Bluebird nests in 1999–2001 and 2003. We compared habitat models that represented bluebird biology and habitat changes from restoration. Two models of nest success that included (1) an increased herbaceous and bare ground cover and (2) increased Gambel oak (Quercus gambelii) densities and reduced Ponderosa pine densities were most supported by the data. Increased herbaceous ground cover and Gambel oak density likely represent improved invertebrate assemblages and thus improved forage abundance for nesting bluebirds. Lower Ponderosa pine densities may provide bluebirds with open perches from which to hunt and thereby improve the availability of invertebrates as a food source. We also provide a landscape‐scale example of changes to bluebird habitat quality from treatments, which we recommend as a useful tool in restoration planning.     

Influence of landscape and vegetation characteristics on herpetofaunal assemblages in Gulf Coastal Plain pine forests

Longleaf pine (Pinus palustris) savanna characterized by open-canopy, diverse herbaceous vegetation, and high amounts of bare soil once covered much of the southeastern United States Coastal Plain. The unique structural and vegetative conditions of this ecosystem support endemic reptiles and amphibians that have declined as longleaf pine forests have been lost or degraded. Private working pine (Pinus spp.) forests managed for timber production now occur throughout the southeastern United States and have replaced much of the historical longleaf pine savanna. The examination of herpetofaunal (reptile, amphibian) communities in private working loblolly pine (P. taeda) landscapes, particularly in the western Gulf Coastal Plain is lacking. Using repeated field surveys and hierarchical community occupancy models, we examined occupancy and species richness of herpetofauna across 81 sites spanning gradients of management practices, vegetative conditions, and soil composition in northwestern Louisiana, USA, 2017–2019. Young pine stands (<6 yr) exhibited structural characteristics most similar to mature longleaf pine reference sites (>30 yr), while mid-aged stands (13–26 yr) often featured closed canopy and dense midstory. Vegetation conditions varied widely depending on landscape characteristics and site-specific disturbance regimes. We documented 43 species of herpetofauna, including 9 open-pine-associated species. Occupancy of open-pine-associated herpetofauna was positively associated with open-canopy and understory conditions, and sandy soil area. Sites providing open-canopy conditions were often occupied by open-pine-associated species regardless of overstory type and disturbance method. Overall richness of herpetofauna was greatest at sites with moderate canopy cover outside of sandy soil regions. Working pine landscapes in the western Gulf Coastal Plain can support diverse herpetofaunal assemblages, including open-pine-associated species, when management practices maintain open-canopy conditions on sandy, upland soils. More broadly, our results provide insight into how forest management practices affect herpetofauna and may guide practices that can contribute to conservation value of working pine forests.     

Non-native plantation forests as alternative habitat for native forest beetles in a heavily modified landscape

The once extensive native forests of New Zealand’s central North Island are heavily fragmented, and the scattered remnants are now surrounded by a matrix of exotic pastoral grasslands and Pinus radiata plantation forests. The importance of these exotic habitats for native biodiversity is poorly understood. This study examines the utilisation of exotic plantation forests by native beetles in a heavily modified landscape. The diversity of selected beetle taxa was compared at multiple distances across edge gradients between each of the six possible combinations of adjacent pastoral, plantation, clearfell and native forest land-use types. Estimated species richness (Michaelis–Menten) was greater in production habitats than native forest; however this was largely due to the absence of exotic species in native forest. Beetle relative abundance was highest in clearfell-harvested areas, mainly due to colonisation by open-habitat, disturbance-adapted species. More importantly, though, of all the non-native habitats sampled, beetle species composition in mature P. radiata was most similar to native forest. Understanding the influence of key environmental factors and stand level management is important for enhancing biodiversity values within the landscape. Native habitat proximity was the most significant environmental correlate of beetle community composition, highlighting the importance of retaining native remnants within plantation landscapes. The proportion of exotic beetles was consistently low in mature plantation stands, however it increased in pasture sites at increasing distances from native forest. These results suggest that exotic plantation forests may provide important alternative habitat for native forest beetles in landscapes with a low proportion of native forest cover.     

Prescribed fire is associated with increased floral richness and promotes short-term increases in bee biodiversity in the ponderosa pine forest of the Southern Rocky Mountains

1. Managed low-severity surface fires are frequently implemented in efforts to restore disturbance processes to forests of North America; although the effects of managed fire on forest structure are well-studied, few studies investigate whether these disturbances cascade to impact pollinator communities.
2. We analysed bee-habitat relationships in fire-treated (1- and 3-years post-treatment) and non-treated ponderosa pine stands in Colorado to test wild bee population responses.
3. Observed bee richness and α-diversity were highest in stands 1-year post-fire and had more Anthophora, Bombus, Osmia and Lasioglossum spp. in comparison to 3-year post-fire and non-treated stands. Bee functional groups were responsive to treatments, with more below-ground nesting taxa present in stands 3 years post-fire.
4. Floral richness was the highest mid-growing season (June, July) and within 1-year post-fire stands.
5. A model analysing the effects of foraging and nesting habitat variation on bee assemblages indicated positive association between floral richness and bee α-diversity, but negative relationships with stand basal area. Nesting habitat was not associated with variation in bee assemblages.
6. We conclude that managed fire has positive short-term effects on bee biodiversity that are likely mediated by floral richness. However, these effects were not detectable by 3 years post-treatment in the southern Rocky Mountain region.

     

Effects of patch size and basal area on avian taxonomic and functional diversity in pine forests: Implication for the influence of habitat quality on the species–area relationship

Relationships between avian diversity and habitat area are assumed to be positive; however, often little attention has given to how these relationships can be influenced by the habitat structure or quality. In addition, other components of biodiversity, such as functional diversity, are often overlooked in assessing habitat patch value. In the Sandhills Ecoregion of Georgia, USA, we investigated the relationship between avian species richness and functional diversity, forest basal area, and patch size in pine forests using basal area as a surrogate for overstory structure which in turn impacts vegetation structure and determines habitat quality within a patch. We conducted bird surveys in planted mature pine stands, during breeding season of 2011. We used three classes of stand basal area (BA): OS, overstocked (BA ≥ 23 m²/ha); FS, fully/densely stocked (13.8 m²/ha ≤ BA < 23 m²/ha); and MS, moderately stocked (2.3 m²/ha ≤ BA < 13.8 m²/ha). MS patches showed more structural diversity due to higher herbaceous vegetation cover than other two pine stocking classes of patches. Total species richness and functional richness increased with the size of MS patches, whereas functional divergence decreased with the size of OS patches (p < 0.05). Functional richness tended to be lower than expected as the size of OS patches increased. Greater richness of pine–grassland species was also found at MS patches. Percent cover of MS patches within a landscape influenced positively the richness of pine–grassland species (p < 0.05). Our results suggest that (a) avian species–habitat area relationship can be affected by habitat quality (structural diversity) and varies depending on diversity indices considered, and (b) it is important to maintain moderate or low levels of pine basal area and to preserve large‐sized patches of the level of basal area to enhance both taxonomic and functional diversity in managed pine forests.