Shrubland Habitats Research Articles

Biogeochemistry on the Range: Editor's Note

Editor's Note: In this issue of The Paper Trail, an up-and-coming ecologist and an established biogeochemist take aim at understanding deserts; those “other” places where many would say are too dry and barren for anything interesting to be happening. As the French would say, “au contraire mon frère” and these two can prove it. Eventually ending up at the Jornada Experimental Range (JER), the two researchers made a connection through the established's “islands of fertility” framework that describes the soil development process specifically in desert grasslands and shrubland habitats. The details of his approach and research he conducted are part of what has inspired the up-and-comer to further his research at the JER where not only soils, but fundamental understanding is being built along the way.

Haemosporidian parasite prevalence, parasitemia, and diversity in three resident bird species at a shrubland dominated landscape of the Mexican highland plateau.

BackgroundStudies of avian haemosporidians allow understanding how these parasites affect wild bird populations, and if their presence is related to factors such as habitat loss, degradation and fragmentation, and climate change. Considering the importance of the highland Plateau of Mexico as part of the North American bird migratory route and as a region containing important habitat for numerous bird species, the purpose of this study was to document haemosporidian species richness and how habitat degradation, bird body condition, and distance from water sources correlate with bird parasitemia.MethodsWe assessed the presence of avian haemosporidians in three resident bird species through microscopy and PCR amplification of a fragment of the haemosporidian cytochrome b gene. Average parasitemia was estimated in each species, and its relationship with habitat degradation through grazing, bird body condition and distance from water bodies was assessed.ResultsHigh levels of parasitemia were recorded in two of the three bird species included in this study. Four lineages of haemosporidians were identified in the study area with nearly 50 % prevalence. Areas with highly degraded shrublands and villages showed higher parasitemia relative to areas with moderately degraded shrublands. No strong relationship between parasitemia and distance from water bodies was observed. There were no significant differences in prevalence and parasitemia between the two bird species infected with the parasites. Two of the sequences obtained from the fragments of the parasite’s cytochrome b gene represent a lineage that had not been previously reported.ConclusionsHaemosporidian diversity in arid zones of the Mexican highland plateau is high. Shrubland habitat degradation associated to the establishment of small villages, as well as tree extraction and overgrazing in the surroundings of these villages, significantly enhances parasitemia of birds by haemosporidians.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1569-3) contains supplementary material, which is available to authorized users.

Age- and season-specific variation in local and long-distance movement behavior of golden eagles

Animal movements can determine the population dynamics of wildlife. We used telemetry data to provide insight into the causes and consequences of local and long-distance movements of multiple age classes of conservation-reliant golden eagles (Aquila chrysaetos) in the foothills and mountains near Tehachapi, California. We estimated size and habitat-related correlates of 324 monthly 95 % home ranges and 317 monthly 50 % core areas for 25 birds moving locally over 2.5 years. We also calculated daily, hourly, and total distances traveled for the five of these birds that engaged in long-distance movements. Mean (±SD) monthly home-range size was 253.6 ± 429.4 km2 and core-area size was 26.4 ± 49.7 km2. Consistent with expectations, space used by pre-adults increased with age and was season-dependent but, unexpectedly, was not sex-dependent. For all ages and sexes, home ranges and core areas were dominated by both forest & woodland and shrubland & grassland habitat types. When moving long distances, eagles traveled up to 1588.4 km (1-way) in a season at highly variable speeds (63.7 ± 69.0 km/day and 5.2 ± 10.4 km/h) that were dependent on time of day. Patterns of long-distance movements by eagles were determined by age, yet these movements had characteristics of more than one previously described movement category (migration, dispersal, etc.). Our results provide a context for differentiating among types of movement behaviors and their population-level consequences and, thus, have implications for management and conservation of golden eagle populations.

Predicting the effects of habitat loss on corsac fox occupancy in Mongolia

AbstractLandscape change affects the distribution of wildlife and represents a conservation concern, especially in Asia, which is experiencing rapid development. We examined the impacts of landscape change on corsac foxes in Mongolia. We addressed 2 questions: 1) how do common features of a landscape, such as habitats, topography, and human structures, shape the distribution of the species? and 2) how will the loss of those features affect distribution? We developed an occupancy model based on locations (n = 2,437) collected in Ikh Nart Nature Reserve, then estimated the marginal loss in average occupancy across the landscape when features were removed. The model with the most support indicated that occupancy was best described by the additive combination of open plain, tall grassland, and shrubland habitats. Average occupancy across the reserve was 22% under current conditions. Simulations involving the removal of each habitat resulted in a marginal loss of 12%, 35%, and 49% in average occupancy, respectively. The loss of all 3 habitats, as expected under climate change projections, will probably make the landscape unsuitable. The results provide the first model of corsac fox occupancy, which can be used to examine distribution and impacts of change in other parts of the species’ range. They also suggest that managers should plan conservation activities to allow corsac fox distribution to shift northward as the region becomes warmer and drier and vegetation communities change.

Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem.

Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis). Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists.

A River Basin over the Course of Time: Multi-Temporal Analyses of Land Surface Dynamics in the Yellow River Basin (China) Based on Medium Resolution Remote Sensing Data

The Yellow River Basin is one of China’s most densely-populated, fastest growing and most dynamic regions, with abundant natural resources and intense agricultural production. Major land policies have recently resulted in remarkable landscape modifications throughout the basin. The availability of precise regional land cover change information is crucial to better understand the prevailing dynamics and underlying factors influencing the current processes in such a complex system and can additionally serve as a valuable component for modeling and decision making. Such comprehensive and detailed information is lacking for the Yellow River Basin so far. In this study, we derived land cover characteristics and dynamics from the complete last decade based on optical high-temporal MODIS Normalized Differenced Vegetation Index (NDVI) time series for the whole Yellow River Basin. After filtering and smoothing for noise reduction with the use of the adaptive Savitzky–Golay filter, the processed time series was used to derive a large variety of phenological and annual metrics. The final classifications for the basin (2003 and 2013) were based on a random forest classifier, trained by reference samples from very high-resolution imagery. The accuracy assessment for all 18 thematic classes, which was based on a 30% reference data split, yielded an overall accuracy of 87% and 84% for 2003 and 2013, respectively. Major land cover and land use changes during the last decade have occurred on the Loess Plateau, where land and conservation reforms triggered large-scale recovery of grassland and shrubland habitat that had been previously covered by agriculture or sparse vegetation. Agricultural encroachment and urban area expansion are other processes influencing the dynamics in the basin. The necessity for regionally-adapted land cover maps becomes obvious when our land cover products are compared to existing global products, where thematic accuracy remains low, particularly in a heterogeneous landscape, such as the Yellow River Basin. The basin-wide novel land cover and land use products of the Yellow River Basin hold a large potential for climate, hydrology and biodiversity modelers, as well as river basin and regional governmental authorities and will be shared upon request.

Mass Change Values of Landbird Migrants at an Inland Stopover Site Dominated by Nonnative Vegetation

Abstract Early successional habitats are declining in eastern North America while at the same time remaining habitats are being invaded by a suite of nonnative shrub species. While the significance of these transitional habitats to breeding birds is well known, increasing evidence suggests they are important during the postfledging/premigratory and migratory periods, not only for shrub-nesting species but also for many species that breed in late-successional habitats. Additionally a number of studies suggest exotic species have the potential to alter habitat quality, in turn affecting the fitness of migratory landbirds. The purpose of this study was to evaluate fitness correlates associated with migrant use of shrubland habitat dominated by nonnative honeysuckle (Lonicera spp.) in order to gauge habitat quality for spring migrants using an inland stopover site in northeastern Pennsylvania. We used estimates of mass change as our fitness indicator, with positive mass change indicating quality habitat. Our ...

The Relative Influence of Road Characteristics and Habitat on Adjacent Lizard Populations in Arid Shrublands

Abstract As road networks continue to expand globally, indirect impacts to adjacent wildlife populations remain largely unknown. Simultaneously, reptile populations are declining worldwide and anthropogenic habitat loss and fragmentation are frequently cited causes. We evaluated the relative influence of three different road characteristics (surface treatment, width, and traffic volume) and habitat features on adjacent populations of Northern Sagebrush Lizards (Sceloporus graciosus graciosus), Plateau Fence Lizards (S. tristichus), and Greater Short-Horned Lizards (Phrynosoma hernandesi) in mixed arid shrubland habitats in southwest Wyoming. Neither odds of lizard presence nor relative abundance was significantly related to any of the assessed road characteristics, although there was a trend for higher Sceloporus spp. abundance adjacent to paved roads. Sceloporus spp. relative abundance did not vary systematically with distance to the nearest road. Rather, both Sceloporus spp. and Greater Short-Horned Liz...

Ant Assemblages of New York State Inland Pine Barrens

Ants are major contributors to ecological processes including soil development, nutrient cycling, and seed dispersal in the northeastern US and around the world. However, distributions of these influential invertebrates in the inland Pitch Pine barrens of New York State are poorly understood. I used quadrat searches and pitfall traps to systematically sample ant assemblages along transects in open habitats at 3 of these inland barrens. My results demonstrate that (1) inland Pitch Pine barrens in New York support high ant-species density, including rare species; (2) as in other regions, shrubland habitats appear to support higher ant-species density than grassland habitats in the Northeast; and (3) shrubland and grassland ant-assemblages in these barrens are compositionally distinct.

Measuring the effectiveness of conservation programs for shrubland birds

Disturbance-dependent habitats such as grasslands and shrublands are declining in many regions. To mitigate these declines, government agencies are using anthropogenic disturbances like logging and mowing to mimic natural ones. Because these programs can be costly or controversial, measuring their effectiveness is important. Here, we evaluate the conservation effectiveness of shrubland management for 15 bird species in Massachusetts, USA. Because shrublands are constantly changing in extent and location, we suggest that the key measure of conservation effectiveness should be how managed areas contribute to habitat availability. We used remotely-sensed data to assess the total area of shrublands in Massachusetts and consulted managers and a timber-harvest database to determine contributions of management by government agencies and non-governmental conservation organizations. We calculated species-specific habitat availability based on the habitat relationships of individual bird species. The area of potential habitat for shrubland birds in Massachusetts averaged 35,000 ± SD of 11,300 ha. Of this total, an average of 20% ± 15% exists because of management by government and NGOs. Management was most important for birds that nest primarily in uplands and avoid wetlands. We conclude that active management by government agencies and NGOs provides a substantial proportion of shrubland habitat in Massachusetts. With habitat on private property being lost to development or succession, active management will be even more important in the future.

Successful reintroduction of red-tailed phascogale to Wadderin Sanctuary in the eastern wheatbelt of Western Australia

Red-tailed phascogales (Phascogale calura) were reintroduced to Wadderin Sanctuary in the eastern wheatbelt of Western Australia in April 2009 with individuals sourced from remnant native vegetation on farmland some 180 km to the west. Their establishment was monitored initially by radio-telemetry and trapping, and subsequently by the checking of nest boxes both within and outside the sanctuary. Translocated phascogales established well and bred successfully in their first season. Phascogales remain extant at Wadderin more than five years after release and appear to be abundant and to occupy all available habitat. They have spread beyond the fenced sanctuary to adjoining woodland and to shrubland and woodland habitat in a remnant 1.4 km away. Comparison with two other reintroductions of this species (one apparently successful, one not) suggests management and habitat factors that may have contributed to the outcomes.

Registro de presencia y actividades de algunos mamíferos en el Desierto Chihuahuense, México

Introduction: Photographic records are useful tools that had strengthen wildlife mammal studies as a noninvasive methodology providing a wide variety of information. The objective of this study is to document with images (automatic - trail cameras and manually – personal cameras) the species of mammals inhabiting the Mapimi Biospere Reserve (MBR), to highlight the morphologic characteristics that distinguish them, to record the area and vegetation type where each species was found and to determine some of their daily activities. Methods: Between 2009 and 2014, twelve field trips were made to Mapimi. In each trip we placed six trail cameras each at five locations (30 cameras total) for 24 h during six consecutive days, with 51,840 h photographic effort. Two sets of six cameras were placed in grassland habitat and three in shrubland habitat. Each camera was baited with 300 g of alfalfa mixed with sand in a tray placed 3 m from the camera. Between 2011 and 2014 two additional cameras were set to monitor a natural pond on the slope of a small mountain (San Ignacio) in the area with 5,760 h of photographic effort. In total we had 57,600 h of photographic effort. Images were also obtained from manual cameras of the authors while engaged in various research projects in the area with more than 2,000 photographs. These data for some species are directly from animals captured in the locality. Their main morphologic characteristics were highlighted, specific places, type of vegetation where each species was found and some of their daily activities. Results: A total number of five orders, 12 families, 27 genera and 31 species were recorded, representing 49 % of mammals known in the Reserve. With trail cameras 1,714 photos were taken and 15 species were recorded (Table 1). The species with highest number of records were Dipodomys nelsoni ( n = 610), D. merriami ( n = 469) and Netoma leucodon ( n = 335). The ones with the lowest number of photos were Ictidomys mexicanus ( n = 48) and Sylvilagus audubonii ( n = 46, Figure 1).Trail cameras recorded five genera where the species level could not be determined: Myotis sp., Chaetodipus sp. , Peromyscus sp., Ictidomys or Xerospemorphilus . With manual cameras more than 2,000 photos were taken and thirty species were photographed, only 16 were recorded with this method (Table 1). The collared peccary ( Pecari tajacu) was the single species recorded only by trailed cameras. Discussion and Conclusions: Results obtained demonstrated that with trail cameras, morphological characteristics that distinguish most mammalian species can be observed clearly for most small, medium and large species. For some small species (such as Heteromyidae and Muridae) their features cannot be easily noted so their proper identity is difficult to determine. It is also important to discuss that only half of the known mammal diversity in the locality was recorded with trail cameras. Some small (such as Heteromyidae and Muridae rodents and bats), medium (as skunks) or large size species (as pumas) were not recorded with them, even though these cameras are generally considered a very effective method for mammalian inventories. As our results do not support this idea, we strongly recommend to combine direct trapping methods with trail cameras to get more complete and more realistic mammalian inventories. The highest numbers of records obtained with trail cameras were of Dipodomys nelsoni , D. merriami and Netoma leucodon , reflecting their numerical dominance in the ecosystem. Lower number of records of Sylvilagus audubonii, squirrels, deer , peccaries and other mammals are related with their low abundance and they occur only in very specific areas. The low numbers found of Lepus californicus were contradictory with previous studies, where they were much more frequently recorded. Skunks inhabit rocky and hills parts in the Reserve, and the presence of Spilogale gracilis was exceptional and as such represents a new record of this species for the Reserve. Documentation of mammalian species through photographic images contributes to different aspects of their biology that had not been addressed before in this location. Cameras allowed updating of information of some species and helped to identify knowledge gaps that can be addressed in the future to contribute to understand the dynamics of the mammal community in the Chihuahuan Desert. Key words: Manual cameras, new record, photographic identification, Spilogale gracilis , trail cameras.

Factors influencing red fox occupancy probability in central Mongolia

The red fox (Vulpes vulpes) occurs widely throughout the northern hemisphere, but few models exist to describe the species’ distribution, especially in Asia where populations are thought to be declining in part due to habitat loss and conversion. We used an occupancy modeling approach to evaluate how landscape factors influence red fox distribution in a steppe region of Mongolia. We collected detection/non-detection data from four surveys of 124 sites from June to September 2010, then evaluated the support of six models to explain occupancy probability in the landscape. Models related occupancy probability to (1) cover habitat, (2) food-rich habitat, (3) open habitat with greater opportunities for vigilance, (4) human developments including herder camps and roads, and (5) marmot colonies, which provide denning sites. We also included a null model that no factors meaningfully influenced occupancy. We detected foxes at 38 sites (31% of total) and during 54 surveys (11% of total). Only the ‘cover’ model demonstrated strong empirical support. This model suggested that occupancy probability was positively influenced by the amount of rocky and shrubland habitats, which provide the most cover and concealment. Red foxes are intensively hunted in Mongolia (and elsewhere in Asia) and probably seek these habitats to avoid detection, suggesting that hunting pressure influences patterns of distribution. Our results provide a model that may be applied to other steppe regions to map red fox distribution and explore how landscape changes may affect the species.

Demographic response of a shrubland bird to habitat creation, succession, and disturbance in a dynamic landscape

Shrubland birds have experienced widespread declines in the eastern United States. Habitat for shrubland birds is typically dynamic, in which available habitat changes temporally and spatially in response to disturbance and succession. Despite widespread concerns among conservationists about shrubland birds, much is still poorly understood regarding fundamental demographic processes associated with the persistence of species in dynamic landscapes, such as the age of colonists, their success upon establishment, the fate of birds displaced by disturbance, and the effect of displaced birds on neighboring territories. To address these knowledge gaps, we studied prairie warblers (Setophaga discolor) between 2008 and 2012 in a pitch pine-scrub oak (Pinus rigida–Quercus ilicifolia) barren consisting of newly created, maturing, and disturbed habitat patches. We found that newly created habitat patches were colonized primarily by younger, second-year males, whereas slightly older shrubland habitat was occupied by site-faithful older birds. Second-year males arrived later on the breeding grounds and had slightly lower pairing success compared to older males; however, they had similar reproductive output as older males. Based on mark-resight analyses, we calculated that 72% of adult males and 14% of banded nestlings returned to the study site in a following year. When territories were subject to high-intensity mowing, fire, or selective herbicide during the non-breeding season, only 14% of the males that returned to the study site stayed on their territories the following year. These returning males that acquired a territory within the study area had similar reproductive success to other birds in the study area and did not negatively affect the pairing or reproductive success of birds occupying adjacent areas. Disturbed territories made up a relatively small portion of the suitable habitat in the study area and disturbance affected a low number of territorial males in any given year. Overall, we found that the short-term effects of shrubland management and habitat disturbance on birds are minimal and subsequently allow young birds to colonize and breed. Moreover, the long-term effects of management are beneficial by maintaining ephemeral shrubland habitat for immigrating and site-faithful birds.

The devil is in the dispersers: predictions of landscape connectivity change with demography

Summary Concern about the effects of habitat fragmentation has led to increasing interest in dispersal and connectivity modelling. Most modern techniques for connectivity modelling have resistance surfaces as their foundation. However, resistance surfaces for animal movement are frequently estimated without considering dispersal, despite being the principal natural mechanism by which organisms move between populations. We collected Global Positioning System data over 10 years from 50 African lions Panthera leo (11 male natal dispersers, 20 adult males and 19 adult females) and used a path level analysis to parameterize demographic‐specific resistance surfaces for the Kavango Zambezi Transfrontier Conservation Area (KAZA) in Southern Africa. Lion path selection varied according to demographic grouping: adult females were most averse to risky landscapes such as agro‐pastoral lands, towns, areas of high human density and highways. Male natal dispersers were the least‐risk averse suggesting they are potentially the most prone demographic to human–lion conflict. Adults of both sexes selected bushed grassland and shrubland habitats and avoided woodland. Male natal dispersers displayed the opposite trend suggesting con‐specific avoidance and/or suboptimal habitat use. We used the resistance surfaces to calculate factorial least‐cost path networks for each demographic‐specific resistance surface and present results that show substantial differences between predicted patterns of connectivity for male natal dispersers, adult females and adult males. Synthesis and applications. Resistance surfaces are widely used to create connectivity models, which are promoted for use by conservation managers. Our results suggest that the demographic category used to parameterize resistance surfaces may lead to radically different conclusions about connectivity. Failure to include dispersing individuals when parameterizing resistance surfaces intended for connectivity modelling may lead to erroneous conclusions about connectivity and potentially unsound management strategies.

Movements of a juvenile Crowned Eagle (Harpyhaliaetus coronatus) tracked by satellite telemetry in central Argentina.

BackgroundA juvenile Crowned Eagle was tagged at its nest with a satellite transmitter. The Crowned Eagle (Harpyhaliaetus coronatus) is one of the most unknown raptor species from the American continent. Their current distribution ranges from central Brazil to central Argentina, with a total population of 350–1500 individuals across this large area, being thus largely fragmented.ResultsDuring the three years of tracking the bird concentrated its movements in a range spanning for 12845 km2, but concentrating mainly in four smaller areas accounting for 3073 km2. The locations were recorded mainly over shrubland habitats (86.5%), whereas other habitats used were different types of mosaics that included cropland and natural vegetation (forest, shrubland or grassland) close to wetlands.ConclusionsThe home-range estimated for this individual during the whole period was 12845 km2 (according to 95% fixed kernel). However, the bird concentrated most of its movements in smaller areas (as defined above), that accounted for a total of 3073 km2 (50% fixed kernel). During these three years, most of the locations of the juvenile solitary Crowned Eagle were recorded over shrubland habitats (86.5% of the locations). Understanding in a more detailed way the juvenile ranging behaviour and habitat preferences would be of great importance for the conservation of the Crowned Eagle.

The role of territory settlement, individual quality, and nesting initiation on productivity of Bell's vireos Vireo bellii bellii

Variation in habitat quality among territories within a heterogeneous patch should influence reproductive success of territory owners. Further, territory settlement order following an ideal despotic distribution (IDD) should predict the fitness of occupants if territory selection is adaptive. We recorded settlement order and monitored nests in territories occupied by individually marked Bell's vireos Vireo bellii bellii across a range of shrubland habitats in central Missouri, USA. We used an information theoretic approach to evaluate multiple hypotheses regarding the relationship between territory settlement order and seasonal territory productivity (productivity), which we define as the number of young fledged from all nest attempts in a territory. Territory settlement order and arrival date were not analogous and later arriving males displaced early settlers in 13 of 49 territories. Settlement order and lay date together were the best predictors of a territory's productivity; productivity decreased 2.08 young from earliest to latest settlement rank and lay date. Males that defended the same territory in successive years occupied territories with earlier settlement dates, but we found little evidence that age or prior ownership influenced productivity. Territory selection by male Bell's vireos was adaptive because males preferred to settle in territories that had high seasonal offspring production, but even though settlement rank was linked to territory quality, high productivity was only realized on high quality territory when also linked to early nest initiation date. While settlement rank was related to territory quality, obtaining a high quality territory had to be combined with early nest initiation to maximize productivity. We found support for the IDD hypothesis because the highest quality territories, (i.e. most productive), were settled earlier. Research that identifies high quality habitat by linking individual fitness with habitat characteristics may elucidate the importance of habitat quality, individual experience and temporal factors to productivity of Bell's vireos.

Measuring and mapping the influence of landscape factors on livestock predation by wolves in Mongolia

Gray wolves (Canis lupus) are a top predator in northern Asian ecosystems and often perceived as a threat to livestock. As a result, wolves are heavily persecuted and populations have declined throughout much of the region. Understanding the dynamics of wolf-livestock conflict is important for developing conservation actions that benefit wolves and human livelihoods. We measured the influence of landscape factors on patterns of wolf-livestock conflict in Ikh Nart Nature Reserve, Mongolia by modeling livestock predation risk using a partitioned Mahalanobis D2 (k) analysis. We based the model on 44 known predation sites obtained through 102 interviews with rural pastoralists and mapped risk at a 500 m spatial scale. Four factors strongly influenced predation risk at a given site in the landscape including distance to nearest ger camp, and the percent of surrounding tall vegetation, shrubland, and forbland habitat. Our results indicate that wolves tend to kill livestock in areas where their detection by humans and livestock is low. Managing wolves in Mongolia will require reducing livestock predation and subsequent retribution killing. This may be achieved by focusing conservation in areas where predation risk is highest, such as habitats with greater vegetation cover and areas near particular ger sites.

Management regime influences shrubland birds and habitat conditions in the Northern Appalachians, USA

ABSTRACTPopulation declines of birds that breed in early‐successional shrubland habitat are of great concern to conservationists throughout the northeastern United States. To help increase the efficiency and effectiveness of efforts to conserve these species and their habitats, we studied birds in temporary forest openings created through even‐aged timber harvest, and permanent wildlife openings maintained through mechanical treatment and prescribed burning in the Northern Appalachians, USA in 2010 and 2011. We assessed the effects of treatment method, time since last treatment, and retained tree cover on shrubland bird abundance and habitat conditions. Burned and mechanically treated wildlife openings differed only in grass and fern cover. Both types of wildlife openings had more grasses and forbs, and less bare ground than silvicultural openings. Six out of 8 focal bird species were less abundant in silvicultural openings than in wildlife openings. In contrast, abundance of only 1 species differed between burned and mechanically treated wildlife openings. Silvicultural openings supported the same species as wildlife openings, indicating that this management option could be used in place of more costly wildlife opening management. However, because birds were more abundant in wildlife openings, maintaining the current population size of shrubland birds under a management strategy based entirely on silviculture would require a 50–300% increase in the area of silvicultural openings, depending on the species. Individual species peaked in abundance at different times post treatment, indicating that managers must maintain a range of early‐successional conditions across the landscape to provide habitat for the entire suite of shrubland birds. Six species exhibited a negative relationship with the basal area of retained conifer cover, and 7 species with deciduous tree cover, indicating that the retention of overstory trees in openings reduced their utility to early‐successional birds. © 2014 The Wildlife Society, 2014.

Does Proximity to Wetland Shrubland Increase the Habitat Value for Shrubland Birds of Small Patches of Upland Shrubland in the Northeastern United States?

The loss of shrubland habitat is linked to population declines for many wildlife species, including several bird species of conservation concern. Conservation agencies in the northeastern United States encourage private landowners to clearcut patches of forest to create shrubland habitat. Many private landowners are only willing to create small clearcuts; therefore, it is important to understand how to maximize the impact of small clearcuts on bird habitat use. In this study we examined whether proximity to wetland shrubland increases the habitat value of small patches of upland shrubland. We conducted point counts at 22 sites containing small patches of upland shrubland ranging in size from 0.1 to 7 ha. Shrubland bird species richness was significantly positively correlated with the proportion of wetland shrubland habitat within 100 m of a site, and with the extent of all shrubland habitat within 100 m, but not with the proportion of upland shrubland. Occupancy modeling indicated that the size of adjacent wetland shrub patches increased occupancy at the sites for five of eight species observed with sufficient rates of detection. Our results suggest that creating clearcuts adjacent to existing areas of wetland shrubland may enhance the habitat value of the patches for shrubland birds.