Habitat suitability modelling for Hirola (Beatragus hunteri) in Tsavo East National Park,Kenya

Hirola (Beatragus hunteri) is one of the most critically endangered antelope whose population is in decline, and its extinction might be the first loss of a mammalian genus in Africa since evolution of modern man. This decline has been attributed to, but is not limited to, habitat loss. Despite hirola introduction to Tsavo East National Park, its population has been stagnating at about 100 since 1996, and the reasons for this are not well documented. This research was aimed at determining the species’ distribution in relation to environmental variables. Data on the presence of hirola were collected between 2008 and 2011 through long‐term monitoring of hirola using aerial census and ground tracking. From this, a model was developed to predict the species’ habitat preferences. The model predicted that hirola preferred areas close to supplemented water, roads, seasonal rivers and water logged areas but avoided areas close to wooded grassland, tsetse infested and rapidly drained areas. This research concludes that hirola distribution depends on availability of fresh grass shoots, shade plants and tsetse‐free areas. To increase hirola carrying capacity in Tsavo East National Park, it calls for habitat manipulation through irrigation of rapidly drained areas, provision of supplemented water, prescribed burning and introduction of tsetse control strategies.     

官山保护区白颈长尾雉栖息地适宜性评价

2009年4月-2009年5月和2009年12月-2010年1月,在江西官山国家级自然保护区对白颈长尾雉(Syrmaticus ellioti) 繁殖期和越冬期的栖息地进行调查。通过实地调查,结合已有研究结果,确定了官山自然保护区白颈长尾雉栖息地适宜性评价因子,即植被类型、海拔、坡度和坡向等4个栖息地因子。基于"被利用生境-可获得生境比较法",以对各评价因子不同梯度的资源选择指数为依据,确定了白颈长尾雉适宜性评价准则。应用ArcGIS 9.3空间分析功能和栖息地片断化指数,对官山保护区白颈长尾雉栖息地进行了适宜性评价。结果表明:在官山自然保护区适宜白颈长尾雉繁殖的栖息地斑块有502个,总面积为3307 hm²,占保护区总面积的28.6%,分离度指数和片断化程度指数分别为0.365和0.912;适宜白颈长尾雉越冬的栖息地斑块有514个,总面积2755 hm²,占保护区总面积的23.8%,分离度指数和片断化程度指数分别为0.443和0.939。官山保护区白颈长尾雉栖息地片断化较严重,片断化现象在白颈长尾雉越冬期加剧。因此,迫切需要采取措施白颈长尾雉现存栖息地进行保护,特别是要高度重视其越冬栖息地的保护。     

基于逻辑斯蒂回归模型的鹭科水鸟栖息地适宜性评价

近年来湿地生态系统遭到不同程度破坏,湿地水鸟及其生存空间日益受到威胁。以香港米埔-后海湾湿地为例,收集2003年1月份与鹭科水鸟密切相关的15个自变量和鹭科水鸟实测数据作为因变量构建逻辑斯蒂回归模型,通过筛选获取9个变量因子,分别为土地利用,NDVI,坡度,降雨,TM4纹理,TM3纹理,道路密度,道路距离,人居密度。经Nagelkerke R2检验模型精度达到0.743,拟合度较高。利用模型结果快速聚类,对栖息地进行适宜性分级,分级结果与同期鹭科水鸟实测数据做拟合,精度达到77.4%。最后采集2009年1月份各变量因子数据对回归方程进行时间尺度检验,与同期实测鹭科水鸟数据拟合精度同样达到75.8%,模型具有较好的通用性。     

Habitat characteristics predict occupancy patterns of the endangered amphibian Litoria raniformis in flow‐regulated flood plain wetlands

Identification of habitat features that are strongly associated with the occurrence of threatened species is important in terms of predicting impacts of habitat change and identifying key habitats for conservation. In this paper, we apply habitat‐based statistical models to predict occupancy patterns of the endangered southern bell frog (Litoria raniformis) across inland New South Wales (Australia). Litoria raniformis previously occupied a wide range of natural and man‐made waterbodies across a large geographic range, including flood plain wetlands, oxbow lagoons, irrigation canals and rice bays. Alteration of natural flooding regimes has affected a large proportion of habitats within the historical range of Litoria raniformis, but it is not clear how these changes have influenced habitat occupancy patterns. Fifty‐two waterbodies were surveyed for presence/absence of Litoria raniformis in 2001 and 2004. Stepwise logistic regression models were generated to select a subset of variables that best predicted occupancy. Using three predictor variables, vacant and occupied habitats could be predicted with an accuracy of 90% and 70%, respectively. The predictor variables were: the interaction between wetland hydrology and complexity of aquatic vegetation, complexity of fringing vegetation and water temperature. While this study demonstrated that a range of waterbody types were occupied by Litoria raniformis, these habitats shared common hydrological conditions and vegetation characteristics. Altered flooding regimes and reductions in the complexity of aquatic and fringing vegetation are likely to increase the probability of localized extinctions of Litoria raniformis populations.     

Chromosome homologies between tsessebe (Damaliscus lunatus) and Chinese muntjac (Muntiacus reevesi) facilitate tracing the evolutionary history of Damaliscus (Bovidae, Antilopinae, Alcelaphini)

Genome-wide homologies between the tsessebe (Damaliscus lunatus, 2n = 36) and Chinese muntjac (Muntiacus reevesi, 2n = 46) have been established by cross-species painting with Chinese muntjac chromosome paints. Twenty-two autosomal painting probes detected 35 orthologous segments in the tsessebe. Hybridization results confirmed that: (i) D. lunatus carries the (9;14) reciprocal translocation that has been proposed to be a derived chromosomal landmark shared by all species of the Antilopinae; (ii) the karyotype of D. lunatus can be derived almost exclusively from the bovid ancestral karyotype through 12 Robertsonian translocations involving 24 ancestral acrocentric autosomes; (iii) in addition to the Rb fusions, pericentric heterochromatic amplification has shaped the morphology of several of the D. lunatus chromosomes. Integrated analysis of these and published cytogenetic data on pecorans has allowed us to accurately discern the karyotype history of Damaliscus (D. lunatus; D. pygargus, 2n = 38; D. hunteri, 2n = 44). The phylogenomic relationships of 3 species reflected by specific chromosomal rearrangements were consistent with published phylogenies based on morphology, suggesting that chromosomal rearrangements have played an important role in speciation within the Alcelaphini, and that karyotype characters are valuable phylogenetic markers in this group.     

Habitat characteristics of grassland Pterostichus species (Coleoptera, Carabidae)

Abstract.

• 1 Pterostichus species were sampled on ninety-two sites distributed throughout north-east England using pitfall trapping.
• 2 The incidence of each species was related to measured site environmental variables using logistic regression.
• 3 Four species groups were identified on the basis of size. The extent of overlap in habitat types between species in each group varied. Two large species overlapped considerably whilst the smaller species showed different responses to one or more environmental variable.
• 4 Possible causes of the differences in habitat overlap between Pterostichus species are discussed.

     

Habitat Selection by Prairie Dogs in a Disturbed Landscape at the Edge of Their Geographic Range

ABSTRACT Although habitat attributes of black-tailed prairie dog (Cynomys ludovicianus) colonies have been described for central and northern portions of the species' geographic range, little is known about these associations at the southern edge of this species' distribution. Because high-quality habitats are expected to be scarcer at the edge of the species' geographic range, different patterns of habitat selection might emerge in these populations. We analyzed habitat selection by black-tailed prairie dogs in a human-disturbed mosaic of desert grasslands and shrublands in northwestern Chihuahua, Mexico. We contrasted 151 used and 133 unused habitat units producing 11 case-control logistic regression models to explain site occupancy by prairie dogs with different combinations of environmental variables. Prairie dogs from Chihuahua occupy sites similar in most respects to sites in more northern regions, although these prairie dogs appear to be more tolerant of increased shrub density and reduced herbage cover. We found that site occupancy was best modeled by positive effects of soil moisture level, cover of forbs, cover of unpalatable vegetation, cover of bare ground, and amount of prairie-dog colony area within 1 km and by the inverse of altitude, shrub density, herbage height, and amount of hostile habitat within 1 km. The 2 most significant variables were herbage height and shrub density, which might reflect the prominent role that visibility plays in habitat selection by prairie dogs. In contrast, we found weak evidence that human features have significant impacts on site occupancy by prairie dogs. Our results support the prediction that environmental conditions of sites used by prairie dogs in edge regions partially differ from those observed in more northern latitudes. We suggest that reserve managers focus conservation efforts on areas with short vegetation, low density of shrubs, and high herbage cover, conditions that could be promoted by controlled burns, herbage mowing, and mechanical removal of shrubs.     

Seasonal Habitat Associations of the Wolverine in Central Idaho

ABSTRACT Although understanding habitat relationships remains fundamental to guiding wildlife management, these basic prerequisites remain vague and largely unstudied for the wolverine. Currently, a study of wolverine ecology conducted in Montana, USA, in the 1970s is the sole source of information on habitat requirements of wolverines in the conterminous United States. The Montana study and studies conducted in Canada and Alaska report varying degrees of seasonal differences in wolverine habitat use. This article provides an empirical assessment of seasonal wolverine habitat use by 15 wolverines (Gulo gulo) radiotracked in central Idaho, USA, in 1992–1996. We controlled for radiotelemetry error by describing the probability of each location being in a habitat cover type, producing a vector of cover type probabilities suited for resource selection analysis within a logistic regression framework. We identified variables that were important to presence of wolverines based on their strength (significance) and consistency (variability in coeff. sign) across all possible logistic regression models containing 9 habitat cover types and 3 topographic variables. We selected seasonal habitat models that incorporated those variables that were strong and consistent, producing a subset of potential models. We then ranked the models in this subset based on Akaike's Information Criterion and goodness-of-fit. Wolverines used modestly higher elevations in summer versus winter, and they shifted use of cover types from whitebark pine (Pinus albicaulis) in summer to lower elevation Douglas fir (Pseudotsuga menziezii) and lodgepole pine (Pinus contorta) communities in winter. Elevation explained use of habitat better than any other variable in both summer and winter. Grass and shrub habitats and slope also had explanatory power. Wolverines preferred northerly aspects, had no attraction to or avoidance of trails during summer, and avoided roads and ungulate winter range. These findings improve our understanding of wolverine presence by demonstrating the importance of high-elevation subalpine habitats to central Idaho wolverines.     

Scale for resource selection functions

Resource selection functions (RSFs) are statistical models defined to be proportional to the probability of use of a resource unit. My objective with this review is to identify how RSFs can be used to unravel the influence of scale in habitat selection. In wildlife habitat studies, including radiotelemetry, RSFs can be estimated using a variety of statistical methods, all of which can be used to explore the role of scale. All RSFs are bounded by the resolution of data and the spatial extent of the study area, but also allow predictor covariates to be measured at a variety of scales. Conditional logistic regression permits designs (e.g. matched case) that relate the process of habitat selection to a limited domain of resource units that might better characterize what is truly ‘available’ to the animal. Scale influences the process of habitat selection, e.g. food resources are often selected at fine spatial scales, whereas landscape patterns at much larger scales typically influence the location of home ranges. Scale also influences appropriate sampling in many ways: (1) heterogeneity might be obliterated (transmutation) if resolution or grain size is too large, (2) variance of habitat characteristics might be undersampled if extent or domain is too small, (3) timing and duration of observations can influence RSF models, and (d) both spatial and temporal autocorrelations can vary directly with the intensity of sampling. Using RSFs, researchers can examine habitat selection at multiple scales, and predictive models that bridge scales can be estimated. Using Geographical Information Systems, predictor covariates in RSF models can be measured at different scales easily so that the predictive ability of models at alternative spatial and temporal domains can be explored by the investigator. Identification of the scale that best explains the data can be evaluated by comparing alternative models using information‐theoretic metrics such as Akaike Information Criteria, and predictive capability of the models can be assessed using k‐fold cross validation.     

Predictive Model of Habitat Suitability for the Marbled Murrelet in Western Washington

Abstract: The marbled murrelet (Brachyramphus marmoratus) is a small Pacific seabird with a breeding range that extends from the Aleutian Islands to central California. Throughout most of its breeding range, it uses mature and old-growth coniferous forests as nesting habitat. Although most murrelets seem to nest within 60 km of the coast, occupied nesting habitat has been identified as far as 84 km from the ocean in Washington state. Due to the extensive inland distances within which birds are known to breed, the area requiring surveys to identify breeding sites can be enormous. Therefore, the standard 2-year survey protocol can be expensive and time-consuming for forest management agencies and companies to administer. We developed a logistic regression model to determine whether a suite of forest structural characteristics could be used to reliably predict occupancy of a forest patch by marbled murrelets. We tested the performance of the final model using cross-validation procedures and a sample of independent sites. We used 50 sites surveyed for marbled murrelets to estimate the model, and 48 independent sites were available to test model performance. All 50 sites were on private forestland owned by Rayonier located in the western lowlands of Olympic Peninsula within the Sitka spruce and western hemlock transition zones. We sampled forest habitat at each site, and we collected information on 15 explanatory variables. The best-fitting logistic regression model contained variables that measured number of canopy layers (P<0.001, approx. F test) and mistletoe (Arceuthobium sp.) abundance (P = 0.031, approx. F test). The model misclassified 2 of 33 (94% correct) unoccupied sites as occupied using a classification cut-off (c) of c=0.25. In the other direction, under cross-validation the final model misclassified 2 of 17 (88% correct) occupied sites as unoccupied. On a test of the model against an independent sample, using a classification cut-off value of c = 0.25, the final model correctly classified 36 of 48 sites (75% correct). The final model misclassified 3 of 31 occupied sites as unoccupied (90% correct). Use of predictive models could greatly reduce the amount of forest that requires surveys by screening out those sites with little probability of use and by focusing remaining effort on higher probability sites, resulting in a higher likelihood of identifying occupied sites and thereby more efficiently conserving marbled murrelet nesting habitat.     

动物的生境选择

动物的生境选择颜忠诚陈永林（中国科学院动物研究所,北京１０００８０）ＨａｂｉｔａｔＳｅｌｅｃｔｉｏｎｉｎＡｎｉｍａｌｓ．ＹａｎＺｈｏｎｇｃｈｅｎｇ,ＣｈｅｎＹｏｎｇｌｉｎ（ＩｎｓｔｉｔｕｔｅｏｆＺｏｏｌｏｇｙ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｂｅｉｊｉ...     

Habitat Selection of Female Turkeys in a Managed Pine Landscape in Mississippi

Abstract: Intensive pine (Pinus spp.) management is a dominant form of forest management in the southeastern United States. Previous research has shown that managed pine forests provide suitable habitat for eastern wild turkeys (Meleagris gallopavo silvestris), but little research has examined seasonal habitat selection for female wild turkeys from a landscape perspective, particularly within managed pine landscapes. Therefore, we used a long-term (1986-1993) data set to describe seasonal habitat selection by female wild turkeys, using an information-theoretic approach from a landscape perspective, on an intensively managed pine landscape. Habitat use patterns during preincubation and autumn-winter were indicative of female wild turkeys moving between a bottomland hardwood-agricultural field complex during autumn-winter and upland managed pine stands during the remainder of the year. During spring and summer, female wild turkeys used landscapes primarily composed of intensively managed pine, including thinned and burned stands and roadsides. Our results confirm results of short-term, stand-based habitat analyses on our study area. We recommend variable fire return intervals of 3 to 7 years to improve habitat conditions for wild turkeys within intensively managed pine forests. Further research is needed to examine management actions, such as thinning, prescribed fire, and herbicide use, within the context of wild turkey use of intensively managed pine landscapes.     

Comparative Space Use and Habitat Selection of Moose Around Feeding Stations

ABSTRACT The practice of feeding cervids in winter, either as a supplement to enhance nutritional status or to divert animals away from roads, railways, or vulnerable habitats, is rising noticeably. Moose (Alces alces) densities in Scandinavia are currently at historically high levels, resulting in amplified damage to economically important young Scots pine (Pinus sylvestris) forest stands. Nevertheless, there is limited information as to how diversionary feeding affects herbivore space use and habitat selection. We followed 32 female moose marked with Global Positioning System collars to evaluate 1) if feeding stations serve as attraction points to the extent that habitat-selection patterns resemble those of central-place foragers (i.e., high usage and more uniform selection close to the attraction point), and 2) if moose using feeding sites select young pine stands less than those not using feeding sites. Moose that used diversionary forage concentrated their space use around feeding stations and selected habitats as predicted for a central-place forager with a decreasing probability of using areas away from feeding sites and a low degree of habitat selectivity close to feeding sites. However, moose that used feeding sites continued to select young pine stands to the same extent as moose that did not use feeding sites. Feeding sites were, therefore, not successful in diverting moose away from valuable natural browse, so we recommend wildlife managers establish feeding sites in sacrifice areas where moose browsing is permissible and, if possible, >1 km from young pine plantations.     

Minimum Area Required for Local Populations of Japanese Macaques Estimated from the Relationship Between Habitat Area and Population Extinction

I estimated the minimum area required (MAR) for local populations of Japanese macaques (Macaca fuscata) from empirical data on habitat area and population viability. I used logistic regression analysis to examine the relationship between habitat area and survival/extinction among 50 populations over 50 yr. Estimated habitat areas satisfying 95–99% probability of a population persisting for 100–1000 yr range from 525 to 975 km². However, confidence limits of parameters in the logistic regression equation are very large. Moreover, the number of extinct population might be underestimated in the empirical data. Consequently, a much wider habitat area (>1000 km²) should be considered for actual conservation planning for local populations of Japanese macaques. The method involves fewer variables and assumptions than previous methods of MAR estimation, and therefore may be a more useful way to estimate MAR for various species and regions.     

Habitat selection in whiting

Given a choice of habitats in a laboratory experiment, whiting Merlangius merlangus preferentially spent most time over sand, then gravel and least time over a habitat with emergent structures. The introduction of a predator stimulus increased the preference for the sand habitat for large whiting, whereas small whiting had an increased preference for the habitat with emergent structures.     

Habitat associations of parrots on the Wallacean islands of Buru, Seram and Sumba

Aim To investigate patterns of habitat use in nineteen populations of parrots on three Wallacean islands, and examine the degree to which habitats used by a species can be predicted across islands. Location The Wallacean islands on Buru, Seram and Sumba. Methods A logistic regression method was used to relate the presence/absence of parrot species at census plots to vegetation axes derived from ‘gross’ habitat parameters such as altitude, tree sizes, and percentages of vegetation coverage at different strata. Receiver Operating Characteristic Plots were then used to test predictions of habitat use by conspecific populations on the nearby and distant islands, and by different parrot species on the same island. Results Parrots on Buru and nearby Seram tended to be associated with open-canopied lowland forests, while on the distant and low-lying island of Sumba, the preference was for closed-canopy forests at higher altitudes. There were usually close affinities in habitat usage by conspecific populations on the two nearby islands. One exception was where the species occurred on the two islands as separate subspecies. Habitat preferences on Sumba, however, were so distinct that paradigms developed for Buru and Seram failed to predict distributions on this distant island. Main conclusions For populations on more distant islands, it will usually be better to predict habitat use by considering the habitat used by other parrot species occurring on that island, than a conspecific population from another region. Conservation research programmes which concentrate parrot study on just one or two islands in every region of Wallacea may be more successful than those which ‘run through’ several islands in a group, but which miss out whole regions.