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1. The biases and shortcomings of stepwise multiple regression are well established within the statistical literature. However, an examination of papers published in 2004 by three leading ecological and behavioural journals suggested that the use of this technique remains widespread: of 65 papers in which a multiple regression approach was used, 57% of studies used a stepwise procedure. 2. The principal drawbacks of stepwise multiple regression include bias in parameter estimation, inconsistencies among model selection algorithms, an inherent (but often overlooked) problem of multiple hypothesis testing, and an inappropriate focus or reliance on a single best model. We discuss each of these issues with examples. 3. We use a worked example of data on yellowhammer distribution collected over 4 years to highlight the pitfalls of stepwise regression. We show that stepwise regression allows models containing significant predictors to be obtained from each year's data. In spite of the significance of the selected models, they vary substantially between years and suggest patterns that are at odds with those determined by analysing the full, 4-year data set. 4. An information theoretic (IT) analysis of the yellowhammer data set illustrates why the varying outcomes of stepwise analyses arise. In particular, the IT approach identifies large numbers of competing models that could describe the data equally well, showing that no one model should be relied upon for inference. [ABSTRACT FROM AUTHOR]

As ecological and human pressures on animal populations increase, so does the discussion of the importance of animal biodiversity. This paper presents Sources that can be used to research animal biodiversity and related topics. [ABSTRACT FROM AUTHOR]

During the last decade, there has been a proliferation of statistical methods for studying resource selection by animals. While statistical techniques are advancing at a fast pace, there is confusion in the conceptual understanding of the meaning of various quantities that these statistical techniques provide., Terms such as selection, choice, use, occupancy and preference often are employed as if they are synonymous. Many practitioners are unclear about the distinctions between different concepts such as 'probability of selection,' 'probability of use,' 'choice probabilities' and 'probability of occupancy'., Similarly, practitioners are not always clear about the differences between and relevance of 'relative probability of selection' vs. 'probability of selection' to effective management., Practitioners also are unaware that they are using only a single statistical model for modelling resource selection, namely the exponential probability of selection, when other models might be more appropriate. Currently, such multimodel inference is lacking in the resource selection literature., In this paper, we attempt to clarify the concepts and terminology used in animal resource studies by illustrating the relationships among these various concepts and providing their statistical underpinnings. [ABSTRACT FROM AUTHOR]

The development of methods to analyze habitat selection when resources are defined by several categories (e.g., vegetation types) is a topical issue in radio-tracking studies. The White and Garrott statistic, an extension of the widely used test of Neu et al., can be used to determine whether habitat selection is significant. As well, Manly's selection ratio, a particularly useful measure of resource selectivity by resource users, allows detection of the most strongly selected habitat types. However, when both the number of animals and types of habitat are large, the biologist often has to deal with an excessively large number of measures. In this paper we present a new method, the eigenanalysis of selection ratios, that generalizes these two common methods within the framework of eigenanalyses. This method undertakes an additive linear partitioning of the White and Garrott statistic, so that the difference between habitat use and availability is maximized on the first factorial axes. The eigenanalysis of selection ratios is therefore optimal in habitat selection studies. Although we primarily consider the case where the habitat availability is the same for all animals (design II), we also extend this analysis to the case where the habitat availability varies from one animal to another (design III). An application of this method is provided using radio-tracking data collected on 17 squirrels in five habitat types. The results indicate variability in habitat selection, with two groups of animals displaying two patterns of preference. This difference between the two groups is explained by the patch structure of the study area. Because this method is mainly exploratory, and therefore does not rely on any distributional assumption, we recommend its use in studies of habitat selection. [ABSTRACT FROM AUTHOR]

Polygynous species follow sex-specific spacing patterns to maximize reproductive success, and changes in population density under otherwise stable environmental conditions likely provoke sex-specific responses in spacing patterns. A classical dual reproductive strategy hypothesis posits that female home range size and overlap are set by habitat productivity and remain stable under increasing population density, whereas male home range size and overlap decrease with increased mate competition. An alternative dispersal-regulated strategy predicts that females relinquish part of their home range to philopatric daughters and form matrilineal clusters, while adult male spacing is stable with density-dependent subadult male emigration rates. We used 11 years of telemetry data to assess the response of adult leopard Panthera pardus spacing following the release of harvest pressure. Female annual home ranges and core areas were smaller than in males. Intersexual overlap was larger than intra-sexual overlap in males or in females. As leopard density increased, female home range size and inter-annual fidelity in home range use decreased, and females formed matrilineal kin clusters. In contrast, male leopards maintained large home ranges, and did not track female home range contraction. Spacing dynamics in adult leopards was consistent with dispersal-regulated strategies, and did not support a classical dual reproductive strategy. Our study suggests possible hidden lag effects of harvest disturbance on spacing dynamics that are not necessarily apparent when only assessing demographic recovery of harvested populations. [ABSTRACT FROM AUTHOR]

The aim of our research was to investigate the relative importance of food supply, geological conditions, human activity and neighbouring badger Meles meles territories for location of badger setts in Białowieża Primeval Forest (BPF) within the boundaries of Poland (595 km²). In our study, we included 67 badger setts surveyed in the field as well as 7,563 pseudo-absence points located randomly in each subcompartment of the forest. For each point, 18 habitat and landscape variables were assessed. The data were analysed using the Random Forest model in two stages, i.e. feature selection and variable importance assessment. Our results indicate that the human-related variables for location of badger setts in BPF (strong avoidance of main roads, bimodal reaction to open and built-up areas) were of highest importance. The second most important variable was the distance to neighbouring active main setts (preference of the distance of 2 km from the nearest active main sett). The least important variables were habitat conditions affecting digging possibility and food availability, such as the presence of cambisols or fresh entic podzols made of loamy sands on ablation moraine or aeolian dunes with potential vegetation of thermophilous oak Quercus robur-hornbeam Carpinus begulus forest of fresh pine Pinus sylvestris-oak mixed forest. We conclude that large intact forest complexes function as refuge areas for badger populations if badger mortality is high in open areas relative to the benefits of wide food availability in open areas. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modelling habitat of species necessitates robust identification of relevant environmental variables linked to species distribution. To achieve this, we connect hierarchical patch theory and habitat modelling at multiple scales. We suggest discriminating between ‘circumstancial variables’ and ‘process variables’ on the basis of temporal evolution of the spatial links between species distribution and their environment at different scales. ‘Process variables’ are informative of the ecological processes driving the distribution of organisms at multiple scales. By opposition, ‘circumstantial variable’ provide little insight because their relationship with animal spatial distribution is subject to great variations through time. As a real case study, we investigate the relationships between auk distribution (mainly Uria aalge) and oceanographic landscapes over two scales (i.e. large ∼ 200 km and medium ∼ 50 km) during the wintering season in the Bay of Biscay. Surface salinity, mixed layer depth and chlorophyll a are identified as ‘process variables’ as they are invariably correlated with the spatial distribution of auks, whereas bottom temperature can be viewed as a ‘circumstantial variable’ since the correlation is non-constant through time at large scale. The process variables at large scale are used to model the potential habitat of auks in the Bay of Biscay during the wintering season. At medium scale, only the chlorophyll a is identified as ‘process variable’ and used to model preferential habitat of wintering auks in the Bay of Biscay. The analytical approach proposed here (i.e. multivariate factorial kriging in a temporal context) is an effective framework to model the potential and preferential habitat of a species and can be related to the ecological niche concept and by focusing explicitly on scale dependence, the distinction between the variables that can be used as niche descriptors into species distribution models. Then our method lead to the identification of variables that should be used to define the Grinnellian niche which is defined by environmental conditions on broad scales and the Eltonian niche which focuses on biotic interactions and resource–consumer dynamics that can be measured principally at local scales. [ABSTRACT FROM AUTHOR]

Animal movement and habitat selection behavior are important considerations in ecology, and remain a major issue for successful animal reintroductions. However, simple rules are often used to model movement or focus only on intrinsic environmental cues, neglecting recent insights in behavioral ecology on habitat selection processes. In particular, social information has been proposed as a widespread source of information for habitat evaluation. We investigated the role of explicit breeding habitat selection strategies on the establishment pattern of reintroduced populations and their persistence. We considered local movement at the scale of a single population. We constructed a spatially-implicit demographic model that considered five breeding habitat selection rules: 1) random, 2) intrinsic habitat quality, 3) avoidance of conspecifics, 4) presence of conspecifics and 5) reproductive success of conspecifics. The impact of breeding habitat selection was examined for different release methods under various levels of environmental heterogeneity levels, for both long and short-lived monogamous species. When heterogeneity between intrinsic habitat patch qualities is high, the persistence of reintroduced populations strongly depends on habitat selection strategies. Strategies based on intrinsic quality and conspecific reproductive success lead to a lower reintroduction failure risk than random, conspecific presence or avoidance-based strategies. Conspecific presence or avoidance-based strategies may aggregate individuals in suboptimal habitats. The release of adults seems to be more efficient independent of habitat selection strategy. We emphasize the crucial role of oriented habitat selection behavior and non ideal habitat selection in movement modeling, particularly for reintroduction. [ABSTRACT FROM AUTHOR]

Patterns of resource selection by animals may be influenced by sex, and often change over a 24-h period. We used a dry sclerophyll landscape managed for commercial timber production to investigate the effects of sex and diel period on habitat selection by the swamp wallaby ( Wallabia bicolor). We predicted that selection would be (i) affected by both sex and diel period; and (ii) positively related to lateral cover during the day, but to food resources at night. Non-metric multidimentional scaling indicated that some of the available habitats differed markedly with respect to visibility (an indicator of lateral cover), fern cover, forb cover, wallaby density and a forage quality index, providing the basis for non-random habitat selection. At the landscape scale, wallabies showed strong selection for 5-year-old regenerating sites, selected against 10-year-old regenerating sites and unharvested forest, and avoided recently harvested (3–10 months post-harvest) sites completely. At the scale of individual home ranges, a pooled male and female sample demonstrated selection for unharvested forest over recently harvested sites during both diurnal and nocturnal periods. A separate analysis showed that both sex and diel period influenced the selection of 5- and 10-year-old sites and the surrounding unharvested forest. Using a novel approach, we demonstrated that diurnal habitat selection by both sexes was negatively correlated with visibility, representing stronger selection for areas with more lateral cover. Nocturnal selection by females was positively correlated with values of a forage quality index, but this was not the case for males. We hypothesise that the observed patterns of selection were driven by the need to find food and avoid predators, but were also affected by the different reproductive strategies of males and females. Our results demonstrate the importance of incorporating factors such as sex and diel period into analyses of habitat selection. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The distribution of animals is the result of habitat selection according to sex, reproductive status and resource availability. Little is known about how marine predators investigate their 3-dimensional space along both the horizontal and vertical axes and how temporal variation affects space use. In this study, we assessed the spatio-temporal movement of a sexually dimorphic marine mammal, the grey seal Halichoerus grypus by 1) determining seasonal home range size, 2) testing whether space use of seals was affected by water depth, and 3) investigating the vertical movement of seals according to the maximum depth of each dive. Between 1993 and 2005, we fitted 49 grey seals in the Gulf of St. Lawrence with satellite transmitters. We estimated seasonal 95% fixed-kernel home ranges for each individual. For each seal, we tested for selectivity and preference for 4 water depth classes at the home range scale and within the home range. We also evaluated the proportional number of dives made in each water depth classes according to the maximum depth of each dive. Home ranges were 10 times larger in winter than in summer. Seals generally selected habitats <50 m deep. They also mainly dove to depths of 40 m or less. At both scales of selection, preference for shallow areas decreased in winter. We also observed that adults used shallow habitats more than juveniles to establish their home range. A spatial segregation based on sex also occurred at the finer scale of selection where females were more concentrated in the shallowest parts of their home range than males. Segregation in space use according to age and sex classes occurred at both the horizontal and vertical scales. Our results emphasise the importance of studying habitat selection of marine predators in 3-dimensional space, in addition to the temporal scale. [ABSTRACT FROM AUTHOR]

Estimating the rate of change of the composition of communities is of direct interest to address many fundamental and applied questions in ecology. One methodological problem is that it is hard to detect all the species present in a community. Nichols et al. presented an estimator of the local extinction rate that takes into account species probability of detection, but little information is available on its performance. However, they predicted that if a covariance between species detection probability and local extinction rate exists in a community, the estimator of local extinction rate complement would be positively biased. Here, we show, using simulations over a wide range of parameters that the estimator performs reasonably well. The bias induced by biological factors appears relatively weak. The most important factor enhancing the performance (bias and precision) of the local extinction rate complement estimator is sampling effort. Interestingly, a potentially important biological bias, such as the covariance effect, improves the estimation for small sampling efforts, without inducing a supplementary overestimation when these sampling efforts are high. In the field, all species are rarely detectable so we recommend the use of such estimators that take into account heterogeneity in species detection probability when estimating vital rates responsible for community changes. [ABSTRACT FROM AUTHOR]

1. Long-term effects of conditions during early development on fitness are important for life history evolution and population ecology. Using multistrata mark–recapture models on 20 years of data, we quantified the relation between rearing conditions and lifetime fitness in a long-lived shorebird, the oystercatcher ( Haematopus ostralegus). We addressed specifically the relative contribution of short- and long-term effects of rearing conditions to overall fitness consequences. 2. Rearing conditions were defined by differences in natal habitat quality, in which there is a clear dichotomy in our study population. In the first year of life, fledglings from high-quality natal origin had a 1·3 times higher juvenile survival. Later in life (age 3–11), individuals of high-quality natal origin had a 1·6 times higher adult prebreeder survival. The most striking effect of natal habitat quality was that birds that were reared on high-quality territories had a higher probability of settling in high-quality habitat (44% vs. 6%). Lifetime reproductive success of individuals born in high-quality habitat was 2·2 times higher than that of individuals born in low-quality habitat. This difference increased further when fitness was calculated over several generations, due to a correlation between the quality of rearing conditions of parents and their offspring. 3. Long-term effects of early conditions contributed more to overall fitness differences as short-term consequences, contrary to common conceptions on this issue. 4. This study illustrates that investigating only short-term effects of early conditions can lead to the large underestimation of fitness consequences. We discuss how long-term consequences of early conditions may affect settlement decisions and source–sink population interactions. [ABSTRACT FROM AUTHOR]

Mountain hares ( Lepus timidus) show high site fidelity even though they are non-territorial and sometimes make long excursions to new areas outside their home range. This study investigates how far apart consecutive annual and seasonal home ranges of the same individual are situated, how much they overlap and if habitat preference can explain the observed high site fidelity. The results show that hares usually overlap their previous home range, both between seasons and years, although the seasonal overlap is smaller, indicating that hares show a more pronounced change of areas between seasons than between years. The seasonal habitat selection was very distinct, tracking changing resource availability between seasons, while the annual selection was difficult to interpret as it mixed the seasonal patterns. Consequently, the annual selection seems to be merely an artefact from the more important seasonal selection. I therefore caution that results from habitat selection studies based on annual home ranges that are estimated from animals in seasonally differing environments should be treated with care. It appears that while seasonal home ranges are selected on the basis of resource availability, there is sufficient variation in the strength of this response to suggest that a mountain hare’s local knowledge of an area could also explain fidelity to their annual home ranges. [ABSTRACT FROM AUTHOR]

Eastern Grey Squirrels were first introduced to Vancouver in the Lower Mainland of British Columbia in 1909. A separate introduction to Metchosin in the Victoria region occurred in 1966. I surveyed the distribution and habitat selection of Eastem Grey Squirrels in both locales. Eastern Grey Squirrels spread throughout both regions over a period of 30 years and were found predominantly in residential land types. Some natural features and habitats, such as mountains, large bodies of water, and coniferous forests, have acted as barriers to expansion for Eastern Grey Squirrels. Given that urbanization is replacing conifer forests throughout southern British Columbia, it is predicted that Eastern Grey Squirrels will continue to spread as habitat barriers are removed. [ABSTRACT FROM AUTHOR]

1. Few studies have related metrics of fitness to broad-scale, multivariate patterns of resource selection. 2. Our objective was to relate long-term predation-mortality patterns for adult woodland caribou [ Rangifer tarandus caribou (Banfield)] from Alberta, Canada (1991–2002), with patterns of multivariate habitat selection. 3. We first compared probabilities of radio-tracked caribou dying ( n = 55) from predation in habitats within the home range, controlling for habitat availability, with that expected from habitat selection probabilities for the same animals during life. We then compared survival rates of caribou ( n = 141) possessing dissimilar patterns of habitat selection using a Cox proportional hazards regression model. 4. Patterns in habitat-specific predation mortality differed significantly from expected given probabilities of habitat selection during life ( P < 0·0001). Cox regression indicated that mortality rates of caribou due to predation were affected significantly by and can be predicted from patterns of selection ( P = 0·02). 5. Our results strongly suggest that uplands (primarily mixed deciduous and coniferous forest) present caribou with higher than expected levels of predation risk, and that caribou can avoid predation by maximizing selection of peatlands (open, conifer-dominated bogs and fens). 6. Approaches presented in this study may be useful for ecologists interested in assessing the influence of mortality factors on broad-scale, multivariate resource selection. Linking metrics of fitness to multivariate resource selection will enable us to ask questions of evolutionary ecology once restricted to only the finest ecological scales. Journal of Animal Ecology (2005) 74, 701–707 doi: 10.1111/j.1365-2656.2005.00967.x [ABSTRACT FROM AUTHOR]

The social behavior of six female stumptail macaques (Macaca arctoides) living in a social group of 23–29 individuals was monitored before and after parturition and was compared to the social interactions of six nonpregnant females. Pregnant and control females did not differ in terms of affiliative and most types of agonistic behavior performed or received. After parturition, new mothers interacted with more group members than did control females. New mothers received more grooming initiations but did not differ from control females in the duration of time spent grooming. New mothers also received more frequent contact aggression from adult males and increased frequency of contact aggression toward juveniles. Overall, new mothers received more submissive responses relative to control females. New mothers did not show elevations in overall dominance status, as measured by the direction of agonistic interactions, and still received aggression from dominant individuals at normative rates. These data indicate that new mothers may become focal points for group interactions, but they do not receive more affiliation overall or less aggression than nonmothers. [ABSTRACT FROM AUTHOR]

We studied abundance, habitat use and social structure of an isolated population of guanacos in the Lihue Calel National Park in central Argentina, based on data from foot surveys during 1998–2000. Based on topography and vegetation characteristics we distinguished three types of habitat: hills, valleys and piedmonts, and lowlands. Three types of social groups were observed: solitary males, family groups and male groups. The guanacos used hills preferentially, followed by valley and piedmont. The guanacos avoided the lowlands where the vegetation is dense. Habitat selection, both on a coarse and a fine scale, could be explained by habitat quality and possibly also predator avoidance behaviour. Abundance of guanacos increased by 21% over the 3-year-study period. However, the specificity of habitat requirements of guanacos and the susceptibility of the study area to wildfires could cause guanacos to move into sub-optimal areas were they are more vulnerable to predation and human persecution. [ABSTRACT FROM AUTHOR]