Habitat Improvement Research Articles

Habitat‐related variation in carcass mass of a large herbivore revealed by combining hunting and GPS data

ABSTRACTStudies on habitat–performance relationships that require joint data on fitness and habitat use are still scarce in long‐lived species. Using data from a southern French population of Mediterranean mouflon (Ovis gmelini musimon × Ovis sp.), we proposed an original approach for gaining information on this relationship by combining a fitness proxy (i.e., carcass mass) collected on harvested rams (n = 257) with knowledge on habitat use obtained from other rams (n = 13) fitted with Global Positioning System (GPS) collars. We first evaluated habitat characteristics encountered by harvested animals in hypothesized home ranges corresponding to circles centered on harvest locations. We set circle size to equal an average ram home range. We found that the carcass mass of harvested individuals decreased with aspect diversity (−16.0% from home ranges with the lowest to the highest diversity), mean slope (−9.3% between flat home ranges and steep ones), and decreasing abundance of open areas (−11.3% between the most and the least open areas). We then tested the robustness of our results by simulating circles with variable sizes and whose centers were randomly located around each harvest location. We found similar results confirming that some habitat characteristics that may be related to resource abundance and spatial structure were important drivers of ram carcass mass in this population. Finally, we showed that simulated circles of variable sizes and centered on GPS locations captured well the habitat composition of home ranges of GPS‐collared rams. Combining different sources of information could hence allow drawing robust inference on key habitats in terms of performance, which is of particular interest when including a spatial component in wildlife management and conservation plans and deciding on appropriate habitat improvements. © 2014 The Wildlife Society.

Synergies between site protection and agri‐environment schemes for the conservation of waders on lowland wet grasslands

Two conservation strategies have been put in place in Europe to address precipitous population declines of wading birds that breed on lowland wet grasslands. These are site protection and agri‐environment schemes (AESs) and the two are rarely compared, or their synergy assessed. Increasingly, efforts to recover populations of previously widespread species follow a landscape‐scale approach whereby habitat improvement takes place at key sites through partially overlapping protected area management and AESs. To investigate whether site protection and AESs improve the conservation status of breeding waders and how these interact, we partially repeated a 2002 survey of breeding waders on protected areas (nature reserves and Sites of Special Scientific Interest) and sites with wader‐specific AES options in England in 2009 and 2010. We then assessed the individual and combined effects of these delivery mechanisms on field occupancy, breeding density and population change of four species of declining wader (Northern Lapwing Vanellus vanellus, Common Snipe Gallinago gallinago, Eurasian Curlew Arquata numenius and Common Redshank Tringa totanus). Although results for Curlew differed from the other species, in general field occupancy was positively influenced by conservation delivery mechanisms, with the highest occupancy and breeding densities on land where site protection was combined with wader‐specific AES options. Field occupancy varied between different types of AES, with higher occupancy associated with higher‐level options in fields, particularly those on nature reserves. Outside nature reserves, the history of AES management did not influence wader populations, but within nature reserves and on fields that gained AES management between 2002 and 2009–2010, populations of Curlew and Snipe were more likely to have persisted and population change in Snipe and Lapwing was more positive. We conclude that the conservation of breeding waders will be most effective when site protection and AES management are combined on the same land. Using limited AES money to support management for breeding waders on, around and between the existing network of protected sites will protect remaining populations while presenting opportunities for population expansion in future.

Perception and Management of Spatio-Temporal Pasture Heterogeneity by Hungarian Herders

The goal of our study was to document traditional steppe herders' perception and management of spatial and temporal heterogeneity of forage availability of their seminatural pastures. Ninety-two herders living in the Hortobágy saline steppe, Hungary, Central Europe were interviewed, and participatory observation was used to understand herding and habitat improvement techniques. The herders recognized 47–66 habitat types (mostly grassland types), and listed at least 90 plant species important for grazing. They have a nuanced knowledge of the intra- and interannual variations of forage quality and quantity. They perform very strong and well-planned herding practices. Daily spatial pattern of grazing is, however, often opportunistic and flexible, but has a more-or-less regular year-round cycle, in which marshes and stubbles provide forage in drought periods. Reciprocal learning and continuous communication between the herder and his driving dogs and livestock strongly influence grazing pattern. Herders manage and improve different habitats of their pastures differently by traditional and, less frequently, modern methods. The main method is grazing supplemented by manuring, burning, and removal of spiny weeds. Traditional knowledge of herders could be effectively used in evidence-based conservation and pasture management of European saline steppes; e.g., the reintroduction of some old herding techniques (opportunistic pasture use, grazing of marshes, and burning). Herders' knowledge could also help the fine-tuning and local adaptation of European agri-environmental regulations (e.g., how to balance subsidies for hay-making and grazing in saline steppes). More research is needed, however, on the ecological effects of different traditional grazing techniques, e.g., rotation, manuring, and burning. In general a more complex socio-ecological understanding of the internal and external factors affecting adaptation of the Hortobágy herders to changing environment, society, and European Union policies is needed.

Habitat management influences overwinter survival of mule deer fawns in Colorado

In the absence of natural or anthropogenic disturbance, many pinyon pine (Pinus edulis)–Utah juniper (Juniperus osteosperma) woodland habitats reach late seral stages that encroach into forest openings. This encroachment typically occurs at the expense of browse species that are preferred by mule deer (Odocoileus hemionus). Wildlife managers often treat habitat management as a tool to bolster mule deer populations, but documented changes in deer vital rates in response to habitat manipulations are lacking. We evaluated the effects of different levels of habitat improvement on pinyon pine–Utah juniper winter ranges in Colorado on mule deer overwinter survival. Mule deer fawns that overwintered on areas that received both a traditional mechanical treatment as well as follow-up chemical treatments experienced increased survival ( = 0.768, SE = 0.0851) over fawns on winter range that had only received traditional mechanical treatments or no habitat treatments ( = 0.675, SE = 0.112). When treatment intensity was partitioned into 3 levels: no treatment, traditional mechanical treatments, and advanced treatments comprised of both mechanical and chemical treatments, mule deer fawns inhabiting winter range subjected to advanced treatments experienced higher survival ( = 0.768, SE = 0.0849) than fawns on units that experienced only traditional mechanical treatments ( = 0.687, SE = 0.108), which in turn experienced higher survival than fawns in areas that had received no habitat treatments ( = 0.669, SE = 0.113). Our study provides evidence that habitat management on winter ranges can positively influence a key vital rate for mule deer in pinyon pine–Utah juniper ecosystems. We recommend that as habitat treatments are planned for benefit of mule deer, those plans include follow-up reseeding and weed control efforts. © 2014 The Wildlife Society.

Black Bass and Crappie Use of Installed Habitat Structures in Table Rock Lake, Missouri

AbstractReservoirs are important resources utilized by millions of freshwater anglers annually, but as reservoirs age the quality of the habitat that they provide for fish deteriorates. In 2007, a large‐scale habitat improvement project began on Table Rock Lake, Missouri, with the goal of supplementing existing fish habitat in this large reservoir. Over 2,000 habitat structures composed of cedar, pine, hardwoods, stumps, and rocks were installed between 2007 and 2013. By means of scuba surveys, we evaluated the use of these structures by black bass Micropterus spp. and crappies Pomoxis spp. to determine whether it varied among fish species, fish sizes, and structure types. Black bass were observed utilizing all structure types but appeared to utilize hardwoods most. Covariates such as water depth and visibility at the structure confounded our analysis of black bass use, however, limiting our ability to clearly document differences in use. Crappies never used rock structures, and more crappies were observed on cedar structures than any other type. In Table Rock Lake, black bass were attracted to all structure types and crappies were attracted to all structure types except rock. Since fish use is similar across nearly all habitat types, other factors such as cost and installation times should be considered when planning habitat enhancement projects on large reservoirs.Received August 12, 2013; accepted October 30, 2013

Projecting the impacts of climate change on skipjack tuna abundance and spatial distribution

Climate-induced changes in the physical, chemical, and biological environment are expected to increasingly stress marine ecosystems, with important consequences for fisheries exploitation. Here, we use the APECOSM-E numerical model (Apex Predator ECOSystem Model - Estimation) to evaluate the future impacts of climate change on the physiology, spatial distribution, and abundance of skipjack tuna, the worldwide most fished species of tropical tuna. The main novelties of our approach lie in the mechanistic link between environmental factors, metabolic rates, and behavioral responses and in the fully three dimensional representation of habitat and population abundance. Physical and biogeochemical fields used to force the model are provided by the last generation of the IPSL-CM5 Earth System Model run from 1990 to 2100 under a 'business-as-usual' scenario (RCP8.5). Our simulations show significant changes in the spatial distribution of skipjack tuna suitable habitat, as well as in their population abundance. The model projects deterioration of skipjack habitat in most tropical waters and an improvement of habitat at higher latitudes. The primary driver of habitat changes is ocean warming, followed by food density changes. Our projections show an increase of global skipjack biomass between 2010 and 2050 followed by a marked decrease between 2050 and 2095. Spawning rates are consistent with population trends, showing that spawning depends primarily on the adult biomass. On the other hand, growth rates display very smooth temporal changes, suggesting that the ability of skipjack to keep high metabolic rates in the changing environment is generally effective. Uncertainties related to our model spatial resolution, to the lack or simplification of key processes and to the climate forcings are discussed.

A Comparison of Four Stream Substratum Restoration Techniques Concerning Interstitial Conditions and Downstream Effects

AbstractStream substratum plays a key role for many riverine species and has become a focus topic in the context of structural habitat improvements. There is a lack of studies that compare the effectiveness of different substratum restoration measures. Herein, we compare four restoration techniques (two different gravel introductions, substratum raking and sickle‐formed constrictor) that were carried out in six replicate rivers. Each measure was monitored for changes in physicochemical substratum quality and the effects of the construction work on downstream sites. Generally, the effects on physicochemical substratum quality were highly variable between restoration types and rivers and strongly decreased within 1 year. Most pronounced changes of substratum quality were detected for the gravel introductions. Substratum raking and the sickle‐formed constrictor had the smallest effects, which were dependent on the original substratum composition of the restored sites. At the same time, substratum raking caused an average fine sediment deposition of 17 kg m−2 on downstream sites, being sixfold higher than for the other measures. Consequently, all of the investigated substratum restoration techniques are confined to short‐term improvement of substratum quality. This finding, together with the observed damage on downstream sites, suggests that a rethinking of the currently applied restoration techniques is required, better considering catchment and natural substratum dynamics in river restoration. Copyright © 2014 John Wiley & Sons, Ltd.

Accounting for habitat when considering climate: has the niche of the Adonis blue butterfly changed in the UK?

The dramatic recovery of three species of grassland specialist butterfly threatened with extinction at their high latitude range limits in the 1980s has been attributed to two factors: increased grazing on calcareous grassland sites and warmer air temperatures. Both result in the warming of soil surface temperatures, favourable to the larvae of these species. We address the influence of both of these factors on the habitat usage of the butterfly Polyommatus bellargus, undergoing recovery at its northern range edge. We test the hypothesis that the larval niche of P. bellargus has become less constrained in the past three decades, whilst controlling for changes in habitat structure. Once habitat change has been accounted for we find no evidence for a broadening of the larval niche of P. bellargus. Further, we show that coincident with the recovery of P. bellargus there have been drastic reductions in average turf height across UK chalk grasslands, but changes in air temperature have been highly variable. We conclude that changes to soil surface temperatures caused by reducing turf heights will have been a more consistent influence than air temperature increases, and so habitat improvements through increased grazing will have been the major driver of recovery in P. bellargus. We consider the need to account for changes in habitat when exploring the impacts of recent climate change on local habitats in thermophilous species, and emphasise the continued importance of habitat management to support such species under variable local climates.

Cost-effective targeting of riparian buffers to achieve water quality and wildlife habitat benefits

ABSTRACTThis study develops an integrated economic, hydrologic, and ecological modelling framework to examine cost-effective targeting of riparian buffers to achieve water quality and wildlife habitat benefits. The framework is empirically applied to the Canagagigue Creek watershed in Ontario, Canada to compare the economic costs for establishing riparian buffers under three alternative environmental and ecological constraints: sediment abatement only, habitat improvement only, and riparian buffer acreage only. The results show that riparian buffers targeted for achieving sediment abatement goal are not effective in improving habitat quality. Similarly, riparian buffers identified through habitat improvement goal achieve less sediment abatement as compared to those targeted in the sediment abatement scenario. The trade-offs suggest that agricultural stewardship programmes with joint water quality and habitat improvement goals may need to allocate funds independently for targeting two pools of riparian buffers: for improving water quality only or for improving habitat only.

Weeds and Wildlife: Perceptions and Practices of Weed Managers

Negative impacts of invasive plants or weeds on biodiversity have been well established yet their role in providing key habitats and resources for wildlife has been little understood. Weed removal thus has the potential to adversely affect wildlife but whether this is considered during weed management is poorly known. To determine the extent of this knowledge, we examined the perceptions of weed managers regarding wildlife and weed management in Victoria, Australia. We surveyed 81 weed managers of varying levels of experience from different types of organisations, including state and local government, community groups and private companies. We found 90% of managers had observed wildlife-weed interactions and that most (70%) adjusted management programmes to accommodate wildlife. Despite this, few (19%) had adopted the recommended practice of combining gradual weed removal with re-vegetation. While management programmes included monitoring of native vegetation, consideration of wildlife monitoring in weed management was rare. This highlights the need for management to better understand and respond to wildlife-weed relationships. If the improvement of wildlife habitat is included in the objectives of weed programmes, as it should be, then wildlife should also be incorporated in project monitoring. This would lead to a greater understanding of the role weeds and their management have in each situation and, ultimately, more informed decision making.

Genetic Evaluation of Supplementation‐Assisted American Shad Restoration in the James River, Virginia

AbstractHatchery supplementation programs have been implemented for several populations of American Shad Alosa sapidissima, which are declining across the species' native range due to disrupted access to spawning grounds, habitat degradation, and overfishing. The genetic impacts of stocking Pamunkey River‐origin larvae into the James River American Shad population since 1994 were investigated, and the effects were considered within a regional context by including American Shad populations from other Chesapeake Bay tributaries that also received interbasin stockings from various rivers over the same period. Levels of genetic diversity for microsatellite markers were high in all populations except the Susquehanna River population, which showed a significant decline in diversity between the 1990s and 2007. Before supplementation of James River American Shad, the James and Pamunkey River populations exhibited subtle standardized differentiation among groups (F′CT = 0.012), whereas differentiation was reduced after supplementation (F′CT = 0.007), indicating that supplementation contributed to homogenization of population structure within the two rivers. Chesapeake Bay tributaries also displayed higher levels of differentiation in the 1990s (F′CT = 0.063) than in contemporary, supplemented samples (F′CT = 0.004). Bayesian analyses of population structure among 1990s Chesapeake Bay samples only identified the Susquehanna River as having a distinguishable population, and no population structure was detected among samples collected in the late 2000s. In light of the fact that Chesapeake Bay American Shad populations are not rebounding in response to supplementation, our observation of reduced genetic differentiation among populations is a likely signal of substitution by hatchery‐origin fish rather than increasing natural recruitment. As such, spawning habitat improvement in conjunction with continued baywide fishing regulation may be a more beneficial strategy for restoring viable American Shad populations than continued reliance on supplementation.Received June 5, 2013; accepted February 3, 2014

Regeneración del hábitat en áreas con presencia documentada de especies amenazadas. Una contribución a la conservación asociada a la operación del proyecto Central Hidroeléctrica Miel I, cordillera Central de Colombia, departamento de Caldas

We document conservation contributions of La Miel 1 hydropower station, based upon 18.763 biological registers, of 1.070 species and changes in land cover/use (1991 and 2011) in ca. 20.000 ha. 17 - 23 species with some degree of threat were reported, especially some with small distributional ranges threatened by deforestation. For all terrestrial species the project has allowed habitat improvement, since forest cover changed from 188 ha (6%) to 2.527,3 (89.5%) during the last 20 years. The positive effect is also revealed with a change from many small habitat fragments ( 4.000 ha). Although conservation of biodiversity was not an explicit environmental target, the fact that Miel I have promoted biological research, allows to document its current contributions to species conservation. It is thus proposed that hydropower enterprises may, through habitat protection, restoration and research, join national biodiversity conservation strategies; especially for those projects located in areas where conservation actions are insufficient.

Local and Lake‐Scale Habitat Effects on Abundance, Lengths, and Diets of Age‐0 Largemouth Bass and Bluegill in Indiana Temperate Lakes

AbstractLittoral zones of lentic systems are important nursery habitats for age‐0 fish as they provide foraging habitat and refuge from predation. While local habitat characteristics in a lake's littoral zone can affect abundances, mean lengths, and trophic interactions of age‐0 fish, lake‐scale characteristics may also influence these factors. Given that local and lake‐scale characteristics are probably related, it may be difficult to interpret perceived associations between habitat characteristics and fish population metrics, as well as elucidate consequences of anthropogenic alterations of habitat. We used classification and regression tree (CART) analysis to evaluate relationships between local and lake‐scale habitat characteristics, abundances, and mean lengths of age‐0 Largemouth Bass Micropterus salmoides and Bluegills Lepomis macrochirus collected from glacial lakes in northern Indiana during 2009 and 2010. We also evaluated habitat influences on stomach contents of age‐0 Largemouth Bass. Our results suggest there are complex, multiscale interactions among habitat characteristics and population and diet metrics of age‐0 fish. Site‐specific abundances of both fishes were most strongly associated with local‐scale characteristics (e.g., high densities of Bluegills at sites with dense submerged vegetation), while mean lengths were associated with lake‐scale characteristics (e.g., greater mean length of age‐0 Bluegills and Largemouth Bass in small, shallow lakes). Diet composition of age‐0 Largemouth Bass was strongly related to individual fish length, though local (e.g., percent coverage by vegetation) and lake‐scale (e.g., lake depth) habitat characteristics also affected the type of prey consumed. We suggest that managers consider both local and lake‐scale features when undertaking habitat improvement activities, selecting stocking locations, or otherwise jointly managing habitat and age‐0 lentic fish populations.

A test of The Ecological Limits of Hydrologic Alteration (ELOHA) method for determining environmental flows in the Potomac River basin, U.S.A.

Summary The Ecological Limits of Hydrologic Alteration (ELOHA) method described in Poff et al. (2010) was applied to streams and small rivers in a large central region of the Potomac River basin in the U.S.A. The area, which is topographically complex, has karst geology, is increasingly urban and has few flow‐altering impoundments, allows a test of the flexibility and applicability of the ELOHA method's four steps: build a hydrological foundation, calculate flow alteration, classify streams and develop flow alteration–ecology (FA‐E) relationships. A hydrological foundation of baseline (undisturbed) and current (existing) hydrographs was simulated for 747 catchments using the Chesapeake Bay Program Hydrologic Simulation Program‐FORTRAN (HSPF) model and the Virginia Department of Environmental Quality Online Object Oriented Meta‐Model (WOOOMM) routing module. The outlet of each catchment was associated with one, and sometimes two or more, stream macroinvertebrate sampling sites. Pairing each catchment's simulated current flow with its own simulated baseline flow produced estimates of flow alteration that reflect the combination of natural and anthropogenic factors controlling streamflow in individual catchments. Flow metrics from the baseline and current simulations were compared with observed values from gauged streams in undisturbed and disturbed catchments. The model may have failed to simulate streamflow well in small urbanised catchments on or near karst geology, but observed data were insufficient to fully evaluate model behaviour in these units. Elsewhere, simulated and observed values of 13 of the 15 tested flow metrics generally agreed well. A stream hydrological classification system to account for natural biological variability was not feasible in the study area for two reasons. First, the natural landscape features that most strongly govern undisturbed streamflows (catchment size and karst geology) do not greatly influence undisturbed macroinvertebrate communities. Second, the study area's complex topography ensures that many streams crossed physiographic boundaries or flowed through karst geology before reaching the macroinvertebrate sampling sites. Stream macroinvertebrates responded strongly to alteration in the duration and frequency of both high and low flow events, rise rate, flashiness and magnitude of high flow events. They did not respond to the alteration in middle‐ and low‐magnitude flow metrics, fall rate or extreme low flow frequency. Flow alteration–ecological relationships were developed for combinations of six flow metrics and seven macroinvertebrate metrics using quantile regression and conditional probability methods. Of the seven macroinvertebrate metrics, % scrapers, % clingers and the Chessie BIBI were most affected by flow alteration. Degraded habitat and water quality conditions modify and, if strong enough, conceal the flow alteration–ecological relationships. Water quality and habitat improvements can potentially ameliorate the impacts of flow alteration. Resource managers need to view each stream system holistically and consider all anthropogenic stressors before the impact of existing or future flow alteration can be determined. Overall, the ELOHA approach appears to have worked well in a large river basin with complex topography, karst geology, few flow‐altering dams, many urban areas and macroinvertebrates as the ecological response variables.

Density and habitat requirements of red-legged partridge on Elba Island (Tuscan Archipelago, Italy)

The red-legged partridge (Alectoris rufa, Linnaeus 1758, Phasianidae) is a common game bird in Europe and it is classified as SPEC 2 (Species of European Conservation Concern), that is, a species with unfavorable conservation status due to a marked population decline. Loss of suitable habitat and hunting management are considered among the major causes of its decline. Such a decline can be also related to agriculture intensification, changes in agricultural practices and the abandonment of less productive lands. Habitat suitability models are an important management tool to define the potential distribution range of a given species, design a protected area network, and plan appropriate management actions and evaluate their effects. This study was conducted on Elba Island (Tuscany) in spring 2011 to define the habitat factors that affect the A. rufa distribution in a typical Mediterranean landscape. On this island the species is declining, as it is in other areas of Europe. We carried out point counts in a survey stratified according to vegetation. We formulated Resource Probability Selection Functions following a presence vs. availability design by Binary Logistic Regression Analysis to obtain a map of potential distribution of the species. We observed that the red-legged partridge distribution was mainly linked to the natural habitat with garrigue and perennial meadows, whereas woody landscape had a negative effect. To stop the species decline on the island habitat improvement actions are needed, such as the cutting of dense vegetation to create open areas.

Restoration of Stream Habitat for Blackside Dace, Chrosomus cumberlandensis, in Mill Branch, Knox County, Kentucky

Abstract The US Fish and Wildlife Service has focused the majority of its Blackside Dace recovery efforts on preservation of extant populations, discovery of unknown populations, and delineation of unoccupied suitable habitats. A missing component of its recovery program has been a large-scale habitat improvement project for the species. Between 2006 and 2010, we evaluated the change in Blackside Dace abundance and distribution in response to a 739-m restoration project on Mill Branch, a second-order tributary of Stinking Creek in Knox County, KY We expected Blackside Dace abundance to increase post-restoration and predicted the species would expand its distribution within Mill Branch to include downstream reaches. The improved habitat conditions were expected to lead to increased diversity and abundance of other fishes. Fish surveys produced a total of 14,580 individuals, representing 29 species. For the overall fish community, mean (± SD) species richness in restored reaches (reach la; 21 ±1, and reach ...

Multiscale, presence‐only habitat suitability models: fine‐resolution maps for eight bat species

Summary To manage anthropogenic environmental change for the benefit of biodiversity, we must improve our understanding of the complex relationships between organisms and their environment. We have developed multiscale habitat suitability models (HSMs) for bats, a mobile group of mammals, for a geographically varied region of the UK. We ask whether the models have sufficient accuracy to contribute to informed decision‐making in habitat management and in minimizing the impact of climate change and human infrastructural development. We used acoustic surveys supplemented by catching to gather presence data for eight species from 30 sites across the south of the Lake District National Park in NW England. Species were identified by manual and automated extraction and analysis of echolocation calls. Fine‐resolution (50 and 100 m) habitat maps were generated at twelve spatial scales by calculating the variables across squares of increasing size, from 100 to 6000 m, around each focal 50 or 100 m square. Presence‐only HSM software, MaxEnt, was used to determine the predictive power of each habitat variable at each scale. Multiscale models included data for each variable at the scale at which it had the strongest relationship with the presence of each species. The best multiscale models were selected using fivefold cross‐validation, with backwards, stepwise variable removal, whilst minimizing residual spatial autocorrelation and sampling bias. Further tests with independent field data indicated good model transferability across the entire National Park. Foraging bats were generally most strongly associated with variables measured at small spatial scales and distance measures. However, each species responded differently across the range of scales, and strong associations were also found at the largest scale of analysis (6000 m). Synthesis and applications. The best models for determining habitat suitability had few variables, making them easy to interpret and use in practical conservation planning. The approach is applicable to any taxa for which reliable presence records are available, providing insight into the potential impacts of land‐use and environmental change. Maps identify areas of conservation concern, such as hot spots for diversity, rare or vulnerable species and potential or threatened network corridors, making them useful for ecological impact assessment of proposed developments, and to conservation managers planning habitat creation or improvement.

Low Mitochondrial Dna Sequence Variation in the Microendemic Cuatro Ciénegas PlatyfishXiphophorus gordoni

The desert spring ecosystem of the Cuatro Ciénegas basin, Mexico, hosts an extraordinary but increasingly imperiled assemblage of native and endemic aquatic organisms. Among the more vulnerable to extinction is the microendemic Cuatro Ciénegas platyfish Xiphophorus gordoni, which is at particular risk due to its highly restricted distribution and small population size. Given the growing demands on water resources in this arid region, we conducted a survey of mitochondrial DNA sequence variation in the cytochrome b gene to establish a baseline for long-term genetic monitoring of this endangered species. Fifty-eight specimens were collected from the 2 subpopulations known to persist, Laguna Santa Tecla (27) and Teclitas (31). Three haplotypes were observed across all samples, with 3 and 2 haplotypes observed at Laguna Santa Tecla and Teclitas, respectively. Sequence divergence ranged from 0.02% to 0.03% among variants and averaged 0.317 differences between populations. Haplotype and nucleotide diversities were moderately low in Laguna Santa Tecla (0.467 and 0.0008, respectively) and severely low in Teclitas (0.065 and 0.0001, respectively). Exact tests revealed significant heterogeneity in haplotype distributions between sites (P = 0.006), as did the pairwise estimate of ΦST (0.135; P = 0.005). Tests of deviation from neutrality were nonsignificant. Microendemism of X. gordoni and marginal substitution differences between the few extant haplotypes suggest that low genetic variation is a historical characteristic of this species; however, population declines associated with recent habitat loss have likely further compromised standing levels of genetic variation. Development of a long-term population and genetic monitoring program that incorporates multilocus nuclear DNA markers is advised and should be tied to a more thorough characterization of the basic biology and life history of this species, establishment of captive or refuge populations, and further improvement of habitat.

Multi-scale associations of grassland birds in response to cost-share management of conservation reserve program fields in Illinois

The Illinois State Wildlife Action Plan targeted the Conservation Reserve Program (CRP) as important improvable acres for grassland and grassland-successional bird species of greatest need for conservation. A large portion of CRP grasslands in Illinois and elsewhere lack floristic and structural diversity because of the absence of management and the extensive planting of monotypic grasses such as tall fescue (Schedonorus phoenix). The 2006 Farm Bill included the mid-contract management (MCM) provision requiring landowners with new CRP enrollments to provide habitat improvement midway through the 10–15-year contract duration. We compared the effects of 3 approved MCM regimes (i.e., fall strip disking, fall glyphosate spraying, fall glyphosate spraying followed by spring legume drill-seeding) on grassland bird communities in 60 tall fescue-dominated CRP fields in south-central Illinois during 2006–2008. We modeled relative density of dickcissels (Spiza americana), Henslow's sparrows (Ammodramus henslowii), and eastern meadowlarks (Sturnella magna) as a function of microhabitat, patch-level patterns, and landscape composition using a multi-scale assessment approach. We detected 10 grassland-associated bird species (e.g., Henslow's sparrow, northern bobwhite [Colinus virginianus], sedge wren [Cistothrus platensis], Savannah sparrow [Passerculus sandwichensis], grasshopper sparrow [Ammodramus savannarum]) that are recognized as species of greatest need for conservation under the Illinois State Wildlife Action Plan. Mean total bird densities and species richness were greater in glyphosate-sprayed fields (5.0 birds/ha; 11.5 species) and glyphosate drill-seeded fields (4.4 bird/ha; 12.4 species) than in disked (3.4 birds/ha; 8.7 species) and reference (3.1 birds/ha; 7.5 species) fields. The avian conservation value of glyphosate sprayed and glyphosate drill-seeded fields increased 34.2% and 32.6% post-management, respectively, but we did not detect change in disked and reference fields. Our models indicate that density of each of the focal species is likely associated with changes in plant species diversity and habitat structure resulting from management actions but is also influenced by landscape composition. Despite an overall positive response of the grassland bird communities to glyphosate-based treatment regimes in tall fescue CRP fields in south-central Illinois, the response of Henslow's sparrow density to glyphosate was not consistently positive. © 2013 The Wildlife Society.

Managing Forests for Increased Regional Water Yield in the Southeastern U.S. Coastal Plain

AbstractWith growing populations fueling increased groundwater abstraction and forecasts of greater water scarcity in the southeastern United States, identifying land management strategies that enhance water availability will be vital to maintaining hydrologic resources and protecting natural systems. Management of forested uplands for lower basal area, currently a priority for habitat improvement on public lands, may also increase water yield through decreased evapotranspiration (ET). To explore this hypothesis, we synthesized studies of precipitation andETin coastal plain pine stands to develop a statistical model of water yield as a function of management strategy, stand structure, and ecosystem water use. This model allowed us to estimate changes in water yield in response to varying management strategies across spatial scales from the individual stand to a regional watershed. Results suggest that slash pine stands managed at lower basal areas can have up to 64% more cumulative water yield over a 25‐year rotation compared to systems managed for high‐density timber production, with the greatest increases in stands also managed for recurrent understory fire. Although there are important uncertainties in the magnitude of additional water yield and its final destination (i.e., surface water bodiesvs. groundwater), this analysis highlights the potential for management activities on public and private timber lands to partially offset increasing demand on surface and groundwater resources.