Understanding Of Habitat Selection Research Articles

Ecological dynamics in habitat selection of reindeer: an interplay of spatial scale, time, and individual animal's choice

While striving for “global” species models of habitat selection, spatiotemporal variation in utilization patterns within a particular habitat and intraspecies variation in space use are still poorly understood. We addressed these challenges by exploring habitat use of domesticated reindeer (Rangifer tarandus tarandus), focusing on factors that underlie ecological dynamics in habitat selection. We analyzed habitat selection of 15 (±2) female reindeer in southern Norway separately for (a) region and home range, (b) seasonality, and (c) each Global Positioning System (GPS)-collared reindeer. We explicitly evaluated spatiotemporal and intraspecies variability in habitat selection by applying multivariate ordination techniques based on the niche concept. In contrast to global assumptions, our results reveal a considerable and partly unpredictable amount of variation in habitat selection resulting from the interplay of spatial scale, time, and individual animal choice. Thus, we conclude that across-scale approaches describing animal space use facilitate better understanding of habitat selection instead of finding a single “best” model that indicates the strongest species–habitat relationships.

Behavioural cues surpass habitat factors in explaining prebreeding resource selection by a migratory diving duck

Prebreeding habitat selection in birds can often be explained in part by habitat characteristics. However, females may also select habitats on the basis of fidelity to areas of previous reproductive success or use by conspecifics. The relative influences of sociobehavioural attributes versus habitat characteristics in habitat selection has been primarily investigated in songbirds, while less is known about how these factors affect habitat selection processes in migratory waterfowl. Animal resource selection models often exhibit much unexplained variation; spatial patterns driven by social and behavioural characteristics may account for some of this. We radiomarked female lesser scaup, Aythya affinis, in the southwestern extent of their breeding range to explore hypotheses regarding relative roles of habitat quality, site fidelity and conspecific density in prebreeding habitat selection. We used linear mixed-effects models to relate intensity of use within female home ranges to habitat features, distance to areas of reproductive success during the previous breeding season and conspecific density. Home range habitats included shallow water (≤118 cm), moderate to high densities of flooded emergent vegetation/open water edge and open water areas with submerged aquatic vegetation. Compared with habitat features, conspecific female density and proximity to successful nesting habitats from the previous breeding season had greater influences on habitat use within home ranges. Fidelity and conspecific attraction are behavioural characteristics in some waterfowl species that may exert a greater influence than habitat features in influencing prebreeding space use and habitat selection within home ranges, particularly where quality habitat is abundant. These processes may be of critical importance to a better understanding of habitat selection in breeding birds.

Habitat selection by the viscacha rat (Octomys mimax, Rodentia: Octodontidae) in a spatially heterogeneous landscape

AbstractThe viscacha rat

Annual use of man-made wetlands by the mute swan (Cygnus olor)

This is essential to understand habitat selection by wildlife to manage habitats and populations. Studying the annual use of aquatic habitats provides information on how to manage wetlands for waterfowl, and to predict possible detrimental effects associated with extended usage by these birds. This is particularly important for species like the mute swan (Cygnus olor Gmelin), given its recent dramatic demographic expansion, causing concern in both Europe and America. We studied the extent of usage (swan.days.ha−1) of habitat patches by mute swans in a heterogeneous and fluctuating fishpond landscape. We assessed seasonal differences of swan usage of fishponds, annual variation for a given fishpond, and determined which habitat factors drive swan usage over the year. The seasonal use pattern was regular: a similar proportion of fishponds was used heavily, moderately or lightly in all seasons. Flocking throughout the year and breeding during summer were associated with heavy use of fishponds, i.e. large number of swan.days.ha−1. Flocking on some fishponds during several successive seasons demonstrated that some waterbody provide valuable habitats over time for swans. However, swans did not use individual fishponds to the same extent each season, mostly depending on the fluctuating ecological requirements of swans and variation in habitat properties. Agricultural practices on fishponds drastically affected swan usage during autumn and winter: formerly dried fishponds were used preferentially once reflooded. The specific agricultural crops used during the drought period had no influence though. The large-sized fishponds and fishponds within a dense network of waterbody were the most heavily used by swans throughout the year. Our results may thus be helpful to predict and prevent possible habitat damage by swans. They also provide information on habitats that are valuable for waterfowl species in general, by using mute swans as a proxy for waterfowl requirements.

Hibernation site requirements of bats in man‐made hibernacula in a spatial context

Bat hibernacula selection depends on various spatial and nonspatial variables that differ widely between sites. However, previous studies have focused mainly on nonspatial variables. This research investigated factors that determined the abundance and species richness of hibernating bats in hibernation objects of the New Dutch Waterline, The Netherlands, and determined the relevant scales over which spatial factors operate using regression techniques and ecological-niche factor analyses. The effects of 32 predictor variables on several response variables, i.e., the total bat abundance, species richness, and abundance and presence of bat species, were investigated. Predictor variables were classified as internal variables (e.g., building size, climatic conditions, and human access) or external variables (e.g., ground and vegetation cover and land cover type) that were measured at different spatial scales to study the influence of the spatial context. The internal building variables (mainly the size of hibernacula and the number of hiding possibilities) affected the hibernating bat abundance and species richness. Climatic variables, such as changes in temperature and humidity, were less important. The hibernation site suitability was also influenced by spatial variables at a variety of scales, thereby indicating the importance of scale-dependent species-environment relationships. The absence of human use and public access enhanced hibernation site suitability, but the internal size-related variables had the greatest positive effect on hibernation site suitability. These results demonstrate the importance of considering the different spatial scales of the surrounding landscape to better understand habitat selection, and they offer directives to managers to optimize objects for hibernating bats and to improve management and bat conservation. The analyses have wider applications to other wildlife-habitat studies.

A piecewise linear modeling approach for testing competing theories of habitat selection: an example with mule deer in northern winter ranges

Habitat selection fundamentally drives the distribution of organisms across landscapes; density-dependent habitat selection (DDHS) is considered a central component of ecological theories explaining habitat use and population regulation. A preponderance of DDHS theories is based on ideal distributions, such that organisms select habitat according to either the ideal free, despotic, or pre-emptive distributions. Models that can be used to simultaneously test competing DDHS theories are desirable to help improve our understanding of habitat selection. We developed hierarchical, piecewise linear models that allow for simultaneous testing of DDHS theories and accommodate densities from multiple habitats and regional populations, environmental covariates, and random effects. We demonstrate the use of these models with data on mule deer (Odocoileus hemionus) abundance and net energy costs in different snow depths within winter ranges of five regional populations in western Idaho, USA. Regional population density explained 40% of the variation in population growth, and we found that deer were ideal free in winter ranges. Deer occupied habitats with lowest net energy costs at higher densities and at a higher rate than compared to habitats with intermediate and high energy costs. The proportion of a regional population in low energy cost habitat the previous year accounted for a significant amount of variation in population growth (17%), demonstrating the importance of winter habitat selection in regulating deer populations. These linear models are most appropriate for empirical data collected from centralized habitat patches within the local range of a species where individuals are either year-round residents or migratory (but have already arrived from migration).

Acoustic tagging for counting feeding events of captive Amazonian manatees

The Amazonian manatee is one of four extant species in the mammalian order Sirenia. They are restricted to the freshwater rivers, lakes and floodplains of the Amazonian river basin where they eat floating and emergent aquatic plants. Visual observation of wild manatees is nearly impossible because of the turbid water and tiny exposure of nose at gentle respiration movement, which consequently precludes study of their underwater behaviour. In this study, we applied animal-worn sound recorder (AUSOMS-mini, System Intec Co., Tokyo, Japan) to two captive Amazonian manatees at INPA, Brazil, in order to record their mastication sounds. Five species of aquatic plants were offered to the manatees separately. Mastication-sounds were extracted by custom made software developed on Matlab for off-line analysis. The mastication intervals and temporal sound structure depended on species of plants. In addition, individual difference of mastication intervals observed in the two manatees was probably due to different body sizes. Overnight recording showed that both manatees kept feeding for more than 0.5 hours followed by 1.6 ± 1.3 hours interruption of feeding. Other sounds such as insect calls, rainfall, and vocalizations of other manatees could be useful to understand habitat selection, weather and presence of conspecifics. Acknowledgment Research and Development Program for New Bio-industry Initiatives

Traditional versus non-traditional nest-site choice: alternative decision strategies for nest-site selection

In order to understand habitat selection, it is important to consider the way individual animals assess the suitability of a future reproductive site. One way of investigating mechanisms (such as those involved in nest site selection) is to examine breeding success and habitat characteristics in terms of animals returning to a place where they have already reproduced and using the same location over successive years or searching for new alternatives. This approach seems especially suitable for testing recent hypotheses suggesting that nest site selection is an integrative process that includes the use of social information (e.g. past breeding success of conspecifics). Determining the factors that elicit conservative or innovative behaviour regarding nest-site selection could be important for improving our understanding of habitat selection decisions in animals. More than half of the nests of the long-distance migratory lesser grey shrike Lanius minor, are built in the same or neighbouring trees. We found no evidence that habitat characteristics influence nest-site tradition. On the contrary, social information in terms of the presence of conspecifics and past reproductive success in terms of complete nest failures due to nest predation (but not detailed information such as variation in fledgling number) influenced nest-site tradition. Hence, social information and past reproductive success may play a role in nest-site choice in this species. Our results further demonstrate that previous experience with a nest site does not appear to be beneficial.

Individual flexibility in habitat selection in the ortolan bunting Emberiza hortulana

In order to understand habitat selection in birds, it is important to know how individuals respond when encountering a variety of habitats during dispersal and must choose between them. However, very few field studies have addressed this question. We compared habitat selection of ortolan buntings Emberiza hortulana before and after dispersal events. In Norway, this species has a patchy distribution and breeds in different open habitats of which the two major ones are botanically distinct: raised peat bogs and forest clear‐cuts on dry, sandy soil. There was no evidence that habitat selection of males after natal dispersal was influenced by natal habitat, and 83% changed vegetation type. Habitat selection was random when taking the availability of each vegetation type into account, both at the landscape level and among habitats encountered along likely dispersal routes. Habitat selection after breeding dispersal was not influenced by the habitat of the patch of origin, and 62–71% changed habitat during successive dispersal events. Changing habitat did not seem to affect pairing or breeding success, but decreased with age. Lifetime patterns of habitat selection indicated that the majority (86%) changed habitat one or more times. However, the proportion never changing habitat (14%) was significantly higher than expected if settlement after dispersal was random (5%), suggesting that the majority of males were flexible whereas a minority was habitat conservative. These results provide some of the first systematic evidence based on settlement decisions of individuals that habitat selection of birds can be flexible with regard to vegetation type.

Ontogenetic changes in habitat selection during settlement in a coral reef fish: ecological determinants and sensory mechanisms

The behavior of marine larvae during and after settlement can help shape the distribution and abundance of benthic juveniles and therefore the intensity of ecological interactions on reefs. Several laboratory choice-chamber experiments were conducted to explore sensory capabilities and behavioral responses to ecological stimuli to better understand habitat selection by “pre-metamorphic” (larval) and “post-metamorphic” (juvenile) stages of a coral reef fish (Thalassoma hardwicke). T. hardwicke larvae were attracted to benthic macroalgae (Turbinaria ornata and Sargassum mangarevasae), while slightly older post-metamorphosed juveniles chose to occupy live coral colonies (Pocillopora damicornis). Habitat choices of larvae were primarily based upon visual cues and were not influenced by the presence of older conspecifics. In contrast, juveniles selected live coral colonies and preferred those occupied by older conspecifics; choices made by juveniles were based upon both visual and olfactory cues from conspecifics. Overall, the laboratory experiments suggest that early life-history stages of T. hardwicke use a range of sensory modalities that vary through ontogeny, to effectively detect and possibly discriminate among different microhabitats for settlement and later occupation. Habitat selection, based upon cues provided by environmental features and/or by conspecifics, might have important consequences for subsequent competitive interactions.

Effects of scale on interpreting life‐history characteristics of ungulates and carnivores

ABSTRACTMany life‐history characteristics of large mammals are scale sensitive. We provide examples where varying temporal and spatial scales can affect interpretation of data concerning life‐history characteristics in large herbivores and carnivores and offer recommendations for selecting the most appropriate sampling scale or scales. We also document that some animals make decisions concerning their spatial distribution at scales well beyond the size of the home range. Conversely, other decisions involving sexual segregation of sexes, or where to give birth, may be made at scales below the level of the habitat patch. Such differences in behaviour affect our understanding of habitat selection in large herbivores, and interpreting tradeoffs between acquiring essential resources and avoiding predators. Moreover, some landscape attributes may be selected at one scale, whereas other characteristics of the environment may be selected at another. We argue that even sophisticated models for explaining the ecology and behaviour of mammals benefit from framing specific hypotheses that are related to the to the life‐history characteristics of those animals. We also believe that the failure to consider and select the most appropriate scale, or suite of scales, may lead to the mismanagement of critical natural resources. We forge relationships among scale, life‐history characteristics of mammals, and biodiversity. Finally, we synthesize the literature on scale for large mammals and make recommendations for future research.

Scale‐dependent habitat use in a long‐ranging central place predator

1 It is predicted that the movements of foraging animals are adjusted to the hierarchical spatial distribution of resources in the environment, and that decisions to modify movement in response to heterogeneous resource distribution are scale-dependent. Thus, controlling for spatial scales of interaction with environment is critical for a better understanding of habitat selection, which is likely to follow scale-dependent processes. 2 Here we study the scales of interactions and habitat selection in a long-ranging marine predator foraging from a central place, the yellow-nosed albatross. We use first-passage time analysis to identify the scales of interaction with environmental variables and compositional analysis to study habitat selection. 3 Of 26 birds, 22 adopted an area restricted search (ARS) at a scale of 130 ± 85 km, and 11 of these 22 birds adopted a second, nested ARS scale at 34 ± 20 km. Habitat use differed according to the spatial scale considered. At the oceanic basin macro-scale, birds foraged in pelagic, subtropical waters. Birds commuted to the ARS zones after a c. 1500-km trip to reach predictable turbulence zones from Agulhas return current, where primary productivity was enhanced at large scale. At a smaller, meso-scale, birds increased their search effort according to sea surface height anomalies (SSHa) and chlorophyll-a concentrations (Chl-a), indicating association with productive cyclonic eddies. 4 Among birds, differences in search pattern were noted: 11 birds concentrated their search effort directly at a small scale of 77 ± 22 km, avoiding anticyclonic eddies. The 11 other birds showed two scales of ARS pattern: (i) first at 180 ± 90 km with a preference for high Chl-a concentrations but unrelated to SSHa; and (ii) secondly at a nested scale at 34 ± 20 km related exclusively to SSHa where prey patches were expected to be distributed at this scale. This second group of birds appeared to be less efficient, spending more time at sea for the same mass gain than the first group. 5 Our study is the first to demonstrate scale-dependent adjustments, with interindividual variability, in relation to environmental features for predators with a central-place constraint.

Physically modeling operative temperatures and evaporation rates in amphibians

(1) We designed a physical model that simulates the thermal and evaporative properties of live Western toads ( Bufo boreas). (2) In controlled tests, the model tracked the body temperature of live toads with an average error of 0.3±0.03 °C (test range=4–30 °C). (3) It estimated the evaporative water loss of live toads with an average error of 0.35–0.65 g/h, or about 14% (test range=0.7–9 g/h). (4) Data collected with this physical model should provide an effective way for biologists to better understand habitat selection in toads and other amphibians

Variability of spring habitat selection by isards (Rupicapra pyrenaica)

We studied the influence of snow cover and habitat heterogeneity on altitudinal distribution, grouping patterns, and habitat selection in the isard or Pyrenean chamois (Rupicapra pyrenaica) in a protected area from the beginning of May to mid-June 1992. Data were recorded from a single vantage point that allowed visual observations to be made over a wide range of elevations. Variations occurred in the spatial extension of groups, with no sightings above 1900 m when snow was abundant at high altitude and only a few sightings below 1700 m when small patches remained at high altitude. During a late heavy snowfall, however, most sightings were made at the middle altitudinal range, where adjoining habitats of steep terrain provided areas of reduced snow depth. The frequency of observations of solitary animals increased slightly and was higher in closed than in open habitats. Both a significant habitat effect and a significant interaction between habitat and time period of observations were found for groups of the average size, ≥ 2 individuals. Montane pastures at low altitude were first selected. Then, when snow melted, this habitat was vacated for 1800- to 2000-m subalpine pastures. Regardless of the time period, the areas dominated by rhododendrons and rocks or scree were systematically avoided. We suggest that in order to gain a better understanding of habitat selection by large ungulates, especially in mountainous areas, short-term variations in environmental heterogeneity be considered.

Habitat selection by lynx in the Northwest Territories

An understanding of habitat selection by lynx (Lynx canadensis) in the northern boreal forest is needed to evaluate the potential impacts of habitat modification (wildfire and timber harvesting) on lynx populations. We quantified habitat selection by lynx in a 290-km2study area in the western Northwest Territories from 1989 to 1993 by radio-collaring 27 adult lynx (12 females and 15 males). An 8-class habitat map, produced using Landsat thematic mapper data, was used to assess habitat selection. Lynx used habitats disproportionately to their availability (P < 0.001), both at the landscape level and within home ranges. Dense coniferous and dense deciduous forests had higher selection indices than other habitat classes, and wetland – lake bed complexes and open black spruce (Picea mariana) forests had lower selection indices. Habitat selection did not differ between the sexes or among years (P ≥ 0.4) Habitat alteration by wildfire in the northern boreal forest could significantly affect populations of the lynx and its primary prey, the snowshoe hare (Lepus americanus), particularly by maintaining or increasing the availability of dense forest and other preferred habitats.

Effects of forest fragmentation on a guild of wintering passerines: The role of habitat selection

This study analyses the winter colonization of an archipelago of 31 forests (0·1–350 ha) in central Spain by the guild of pariforms ( Parus, Aegithalos, Regulus, Sitta and Certhia). Two hypotheses are considered: (a) that birds with similar habitat preferences tend to disappear simultaneously with the reduction in forest size, leading to a ‘nested’ pattern of species distribution; or (b) that the species in the smallest forests are a random sample of those found in the larger ones. The results support hypothesis (a). The species that depend on relatively scarce resources, such as tree trunks and junipers Juniperus thurifera ( Sitta europaea, Certhia brachydactyla, Parus cristatus and P.ater) only occupied the largest forests. On the other hand, species that exploit abundant, ubiquitous resources, such as holm oak Quercus ilex foliage ( Regulus ignicapillus and Parus caeruleus), were distributed uniformly throughout all the fragments. These results emphasize the need for a better understanding of habitat selection by species when designing conservation strategies for fragmented populations.