Availability Of Preferred Habitat Research Articles

Increased habitat availability as revealed by LiDAR contributes to the tropicalization of a subtropical butterfly community

AbstractSpecies redistribution through climate change remains a global problem. However, factors such as habitat availability can complicate the attribution of species distribution shifts. We used habitat metrics derived from repeated airborne LiDAR surveys in 2010 to 2020 to examine the underlying causes for the establishment of new butterfly species in Hong Kong. For six species newly arrived since 2000, we built species distribution models using the Random Forest algorithm based on LiDAR data from 2020 to characterize species' preferred habitats across the region. Through hindcasting, we applied the model to LiDAR data from 2010 to observe any changes in the availability of preferred habitat. We found widespread vertical forest growth across Hong Kong and increased probability of occurrence based on increased habitat availability for all six species. The underlying habitat drivers, however, varied significantly across species; two species (Lethe chandica, Notocrypta paralysos) were associated with closed forest while two other species (Prosotas dubiosa, Prosotas nora) were associated with urbanicity. Our results highlight how changes in habitat can occur concurrently with climatic change and together drive the redistribution of biodiversity. Particularly for vertically complex tropical forests, airborne LiDAR data can be leveraged to observe changes in habitat complexity and how these relate to shifts in species distributions.

Diel patterns of habitat use and movement by juvenile and subadult trout cod (Maccullochella macquariensis) in a regulated lowland river

Improved knowledge of habitat use and movements is needed to support recovery of threatened riverine fish species. The trout cod (Maccullochella macquariensis) is a nationally threatened fish species endemic to rivers of the southern Murray–Darling Basin (MDB), Australia. This study investigated diurnal and nocturnal habitat use and movements of trout cod in the Goulburn River, using radio-telemetry. Trout cod typically occupied small reaches (<300 m) of stream during the late spring–summer study period. Larger-scale movements (mostly home-range shifts) and movements onto inundated riparian habitats also occurred during a period of high discharge. Trout cod occupied deeper water further from the bank during the day and shallower water closer to the bank during the night and used areas with slower velocities more than was their availability, particularly during the earlier hours of the day. They also made extensive use of in-stream cover (i.e. wood). Our information on diel habitat use provides a platform to guide informed management (e.g. availability of preferred habitats under different river-discharge scenarios) to improve trout cod population sustainability.

Multi-scale settlement patterns of a migratory songbird in a European primaeval forest

The drivers of animal settlement are core topics in ecology. Studies from primaeval habitats provide valuable but rare insights into natural settlement behaviour, where species are unconstrained by habitat fragmentation and modification. We examined whether territorial male songbirds (wood warblers Phylloscopus sibilatrix) exhibited clustered distributions when settling in extensive primaeval forest. We tested whether settlement patterns were consistent between years, the influence of habitat preference and the spatial extent of these processes. Remote sensing (airborne LiDAR and satellite multi-spectral) and field survey data were combined to investigate settlement at the landscape (tens of km2), plot (46–200 ha) and microhabitat (20 m diameter) scales, by sampling across 5.9 × 4.5 km of the Bialowieza National Park (Poland) during 2018–2019. We assessed bird distribution patterns using nearest neighbour analyses, and habitat preference with generalized linear mixed models. Variation in bird density between plots and years was suggestive of large-scale clustering at the landscape scale. At the local plot scale, any clustering was masked by territoriality, with birds appearing dispersed or randomly distributed. At the microhabitat scale within territories, birds preferred a tall, closed canopy forest structure and avoided a dense herb layer of wild garlic patches. Settlement appeared unconstrained by the availability of preferred habitat at the plot scale, which remained unsaturated. Wood warbler settlement apparently involved hierarchical decisions at multiple spatial scales, compatible with potential social attraction, territoriality, habitat preference or predator avoidance. Selecting an appropriate scale of analysis is an important consideration when assessing the clustering of territorial species. Many songbirds settle in clusters of breeding territories, possibly reflecting patchy habitat quality and/or social attraction. Studies of territory clustering generally come from fragmented, modified habitats, such as secondary forest, which might bias or limit bird distribution. We studied settlement patterns of male wood warblers in an extensive, primaeval forest, where they could exhibit natural behaviour. Spatial analyses of satellite, airborne and field survey data revealed a series of settlement decisions at multiple spatial scales. We found evidence supporting large-scale clustering across the forest, but at the local scale any such clusters were masked by the spacing of birds within territories. A tall forest structure was preferred within the territories, but at larger scales, some birds seemed to compromise habitat quality to settle within a cluster. The results highlight that settlement decisions of animals must be considered at appropriate spatial scales.

The effect of season and post-fire on habitat preferences of the endangered Swayne\u2019s hartebeest (Alcelaphus buselaphus swaynei) in Maze National Park, Ethiopia

BackgroundThe availability of preferred habitats determines the spatial and temporal distribution of herbivores in savanna ecosystems. Understanding habitat preference of a targeted wildlife species is crucial for developing effective conservation strategies. Habitat preference of large grazers in connection to grass height and post-fire effect has been debated for the last century. Here, we examined the effects of season, grass height and burning on the habitat preference on Swayne’s hartebeest (Alcelaphus buselaphus swaynei) in Maze National Park. Data for seasonal habitat selection were collected using both direct observation along established transect lines and pellet counting using permanently established plots. Every month, we measured grass height commonly preferred by Swayne’s hartebeest in grassland habitat. Starting from the first week of burning, we recorded the abundance of Swayne’s hartebeest in both burned and unburned grassland patches.ResultsFrom detected pellets, 94.3% were recorded in the grassland habitat indicating that other habitat types are less used despite their extensive cover > 50% of the Park. During wet and early dry seasons, Swayne’s hartebeest exclusively preferred grassland habitat. We found that 85.2% (n = 1079) and 85.3% (n = 593) of individuals observed in areas with a grass height below 30 cm during wet and early-dry seasons, respectively; while 70.9% (n = 2288) preferred grass height below 30 cm during the dry season. The density of Swayne’s hartebeest in burned grassland area was higher than unburned grassland areas up to 150 days since burning. However, in unburned grassland areas, the density was initially low but showed increasing trend for consecutive days, reaching similar density with burned areas after 150 days since burning.ConclusionSwayne’s hartebeest exclusively preferred grassland habitat, particularly during wet and early-dry seasons, shortest available grass height in all seasons and were attracted to burned grassland areas. Our results suggested that fire played an important role in maintaining habitat quality in grassland, and that management should continue using controlled burning as a tool for the conservation of Swayne’s hartebeest. However, we remain cautious of our findings given the paucity of information regarding other confounding factors and the absence of long-term data on fire disturbance.

Benthic composition influences habitat use and toxicity of coral-dwelling fishes

The distribution and abundance of habitat specialists is often associated with the availability of preferred habitat; however, other environmental features can also influence habitat selection. Coral-dwelling gobies are habitat specialist fishes that depend on the availability of a few key species of coral for their survival and rely on skin toxins to reduce predation risk. This study investigated the influence of benthic substratum around coral colonies on patterns of habitat use and toxicity of two species of coral-dwelling gobies (Gobiodon erythrospilus and Gobiodon histrio) that compete for access to the coral, Acropora nasuta. Field surveys demonstrated that the benthic substratum around A. nasuta coral colonies differed between colonies occupied by G. histrio and G. erythrospilus. Juvenile, single adult and breeding pairs of G. erythrospilus mostly inhabited A. nasuta colonies surrounded by branching corals. In contrast, juvenile and single adult G. histrio associated with A. nasuta coral colonies that had adjacent epilithic algal matrix and G. histrio breeding pairs inhabited colonies surrounded by sand/rubble. Habitat choice experiments demonstrated that both goby species prefer A. nasuta coral colonies with benthic substratum mainly composed by epilithic algal matrix and sand; suggesting that competition for coral colonies in preferred locations could influence patterns of habitat use observed in the field. The substratum around preferred coral colonies also influenced the toxicity levels of associated fishes. Gobies inhabiting A. nasuta coral colonies surrounded by epilithic algal matrix and sand showed higher levels of toxicity than gobies collected from colonies surrounded by branching corals. Given the potential for toxicity level to reduce the risk of predation, this could explain why gobies would compete for access to colonies of the preferred coral species surrounded by epilithic algal matrix and sand. These results show that the habitat use of coral habitat specialist fishes can be affected by the benthic composition around preferred coral colonies and demonstrate how competition for important secondary resources can influence patterns of habitat use.

Role of the preferred habitat availability for small shark (Mustelus schmitti) on the interannual variation of abundance in a large Southwest Atlantic Coastal System (El Rincón, 39°–41°S)

Description of habitat preferences in marine fishes is important in order to understand their spatial distribution and ecology, and are one of the first steps towards conservation. In this paper, we evaluate the influence of environmental conditions (temperature, salinity), location (latitude-longitude, depth), time (year) and availability of preferred habitat on the relative biomass of the narrownose smooth-hound shark (Mustelus schmitti ) in El Rincon (~38°–41°S , was also a significant predictor for relative biomass and was correlated to the main freshwater discharge previous to the fisheries survey. Discussion focused on understanding the spatial ecology of this species. We highlighted how environmental variables become a key issue to understand biomass indices derived from fishery-independent surveys.

Does Reduced Perch Availability Affect Reproduction in the Brown Anole? An Experimental Test in the Laboratory

Abstract The availability of preferred habitat can have numerous effects on an individual's behavior and physiology and, in turn, can affect fitness. In Anolis lizards, different species have evolved specific limb lengths that enable them to perform well in habitats with specific perch characteristics. Indeed, perch width and height have been major drivers in the morphological diversification in this genus. Despite the extensive work on Anolis limb length/perch width relationships, however, the availability of perches (a preferred habitat characteristic) influences aspects of fitness is poorly known. In this study, we housed captive male/female pairs of Brown Anoles (Anolis sagrei) in cages with high and low availabilities of perches and quantified the effect of perch availability on perch use and reproductive variables (egg production, egg mass, interegg interval, yolk steroids, egg hatching success). In the low-perch availability treatment, females spent less time on perches than did females in the high...

Linking conception and weaning success with environmental variation and female body condition in a northern ungulate

Abstract Success or failure of any stage of reproduction is generally related to maternal characteristics and environmental influences. In addition, postreproductive body condition of females should be a function of effort allocated to reproduction. Using data on > 800 female white-tailed deer (Odocoileus virginianus) harvested during 4 years on Anticosti Island (Quebec, Canada), we investigated factors affecting reproductive status, from ovulation to weaning, and measured the resulting effect on female body condition. The probability of ovulation (single or double) increased with female age, but weaning success was unrelated to age. Female reproduction was determined by climatic conditions in each season and the availability of preferred habitat, but high density only affected young primiparous females. More specifically, snowy autumns decreased ovulation rate, dry springs disfavored the production of twins, and cold and snowy winters decreased weaning success. Habitat with high summer plant biomass favo...

High temperature constrains reproductive success in a temperate lizard: implications for distribution range limits and the impacts of climate change

AbstractWe investigated whether the current distribution of Lacerta schreiberi is likely to be constrained by incubation conditions. We used an incubation experiment in the laboratory to examine the effects of temperature and moisture on lizard reproductive traits, in order to clarify the ecological processes that underlie the distribution patterns of this lizard and to build more reliable mechanistic models. We then investigated to what extent range limits of L. schreiberi coincided with those predicted from incubation experiments and actual temperature variation experienced in the field. This was done by intersecting documented presence localities of the species with interpolated spatial layers of soil temperature. Reproductive success (hatching success, morphological traits and growth rates) was strongly and negatively affected by high temperature. In contrast, incubation moisture only affected neonate size and its positive effects were only realized at moderate to low temperature. Documented temperature sensitivity suggests that successful embryonic development is likely to be compromised by available thermal conditions, and that this species is unable to colonize warmer areas such as those where L. schreiberi is absent beyond its distribution range limits. An important addition is that incubation moisture does not appear to influence overall embryonic development. We would expect contemporary climate warming to cause upward elevational shifts which may be more or less critical depending on the availability of preferred habitat.

Winter habitat–space use in a large arctic herbivore facing contrasting forage abundance

We analysed how changes in resource levels influence foraging trade-offs in late winter by wild Svalbard reindeer. Forage plants, and particularly lichens, were less abundant at the overgrazed Broggerhalvoya compared with the neighbouring Sarsoyra. Strong interactions occurred between habitat selection, home range size, and feeding crater selection. At Broggerhalvoya, radiocollared females generally selected productive habitat (high summer NDVI; Normalised Difference Vegetation Index). “Immigrants” at Sarsoyra (dispersed from Broggerhalvoya in early winter) had similar habitat preferences, probably due to past experience. In contrast, “residents” at Sarsoyra were more influenced by abiotic conditions, using habitat with low NDVI, but selecting for high-quality forage (lichens) when cratering. This suggests more quality-based selection at the expense of quantity when forage abundance increases. Habitat–space use relationships also differed between the animal categories, as home range size decreased with availability of preferred habitat. Thus, changes in forage abundance can strongly influence winter habitat–space use interactions in predator-free systems.

Enhanced niche opportunities: can they explain the success of New Zealand's introduced bird species?

ABSTRACTAim The niche hypothesis could explain why some species introduced to new locations reach higher densities than in their native range: it posits that the new environment provides more abundant or higher quality resources or habitat, a more suitable physical environment or both. We investigate whether 11 bird species occur at higher densities in their introduced range than in their native range and whether the differences can be explained by the availability of preferred habitat or the suitability of climatic conditions in their introduced range relative to their native range.Location South Island, New Zealand (the introduced range); UK (the native range).Methods We first develop a series of models that accurately predict the density of 11 bird species at 54 UK farmland sites, which are closely matched to our New Zealand sites, from habitat and climatic variables. We then use these models to predict the density of the 11 species at 54 New Zealand farmland sites and compare the predicted and observed values.Results Actual densities at New Zealand sites were on average (median) 22 times (range: 1–6361) higher than predicted from the UK models and similarly higher than actually observed at comparable UK sites. Habitat and climatic variables can accurately predict bird densities in the UK but grossly underestimate densities for all species except Turdus merula in New Zealand.Main conclusions These findings indicate that factors other than the measured habitat and climatic variables must differ between the two regions and explain the much higher densities of New Zealand birds. We suggest that introduced birds, other than T. merula, in New Zealand may still experience enhanced niche opportunities due to greater availability of higher quality resources within habitats, release from natural enemy regulation, less exposure to extreme weather events, particularly during winter, or some combination of these processes.

Thresholds in landscape connectivity and mortality risks in response to growing road networks

Summary 1. The ecological footprint of a road may extend for several kilometres with overlapping effects from neighbouring roads causing a nonlinear accumulation of road effects in the landscape. Availability of preferred habitat, spatial dependencies between roads and habitat types, and fidelity to traditionally used areas further confound our ability to predict population-level responses of animals to growing road networks. 2. To isolate these effects, we developed an individually based movement model using elk Cervus elaphus L. as a model system. Empirically derived movement rules redistributed elk under different amounts of preferred habitat (clearcuts), road densities, and road development schemes. We tracked potential mortality risk (given time spent near roads) and emigration rates (given declining accessibility of foraging habitat). 3. Design of the road network accounted for up to 30‐55% difference in mortality risk and emigration rates, with the largest differences occurring at intermediate road densities (1‐1·5 km km ‐2 ) when road effects began to saturate the landscape. Maintaining roads in association with clearcuts caused a decline in habitat accessibility equivalent to replacing 50‐75% of these foraging patches with conifer forest. A nine-fold difference in potential emigration was observed after varying elk tolerance for declining habitat accessibility despite holding local movement biases constant. 4. Elk responses to growing road networks were non-linear, exposing thresholds for road density that were reflected in the home range occupancy patterns of a large sample of elk in the region. 5. Synthesis and applications . Our approach provides a means of scaling-up complex movement decisions to population-level redistribution, separating the confounding effects of landscape context from road effects, and exposing thresholds in connectivity and mortality risks for wildlife caused by infrastructure growth. Our model indicated that road densities ≤ 0·5 km km ‐2 yielded the highest probability of elk occurrence where elk were hunted (and sensitive to roads), but disassociating roads from foraging habitats or managing human access to roads may maintain effective elk habitat at substantially higher road densities.

The Odonata of newly constructed ponds with life history and production of dominant species

The species composition of an odonate assemblage from six new ponds in Virginia, USA, was documented, and life histories and production of three dominant odonate taxa (Anax junius (Drury), Gomphus exilis Selys, and Enallagma civile (Hagen)) were determined. The assemblage consisted of 19 species and was numerically dominated by A. junius, G. exilis, E. civile, and libellulids. Production of A. junius, G. exilis, and E. civile was 795 mg DW m−2 yr−1, 27 mg DW m−2 yr−1, and 236 mg DW m−2 yr−1, respectively. Coefficients of variation for production of each species were 50 – 77%, which suggests that variance should be considered in production estimates, especially if results are to be compared across studies or habitats. Low density and production of the dominant species in this study may be a result of inadequate densities of food items and limited availability of preferred habitat in the newly created ponds.

An Index to Assess the Sensitivity of Gulf of Mexico Species to Changes in Estuarine Salinity Regimes

An index of biological sensitivity to changes in freshwater inflow was developed for 44 species in 22 Gulf of Mexico estuaries for adult and juvenile life stages of fishes and macroinvertebrates. The BioSalinity Index (BSI) provides an innovative approach to quantify estuary-specific sensitivity of organisms to changes in estuarine salinity regimes based upon our knowledge of species salinity habitat preferences, the availability of this preferred habitat, and the relative abundance and distribution of species in time and space. We found that a significant difference exists between adult and juvenile life stage sensitivity, with juveniles exhibiting a lower sensitivity to salinity changes than adults, and that a considerable disparity exists in species-specific sensitivities among Gulf estuaries. Likewise, when the full complement of 44 species-level BSIs are averaged, marked differences in assemblage-wide sensitivity are evident across estuaries. The availability of preferred salinity habitat had a greater influence on the BSI for estuarine species than did their relative abundance and temporal distribution. The BSI was applied by members of a 1995 Gulf of Mexico freshwater inflow workshop to identify a subset of estuaries which appear more sensitive to freshwater inflow changes and are candidates for further study.

Foraging Habitat Preferences of Vespertilionid Bats in Britain

The selection of foraging habitats by vespertilionid bats in Britain was quantified using a stratified sample of 1030 1-km squares. Quantitative analysis of habitat preference and avoidance on a large scale indicated that bats were flexible, yet consistent in their habitat use across contrasting landscapes. Habitats associated with broadleaved woodland and water were most preferred, while arable land, moorland and improved grassland were strongly avoided. Linear vegetation features were selected in all landscapes, demonstrating the importance of habitat continuity to bats. The availability of preferred habitats was low and patchy in all landscapes, indicating that bats have specialized habitat requirements. Differences in habitat selection between landscape types and possible factors influencing habitat selection are discussed. Habitat selection analysed on a local scale demonstrated the same consistent preference for woodland, riparian and corridor habitats across 19 discrete land classes. Management policies for bats in Britain should endeavour to preserve and enhance the availability of woodland, water margins and linear corridor habitats. Lack of continuity of the landscape, loss and fragmentation of habitat patches plus deterioration of the quality of such patches may pose a threat to bat populations.