scholarly journals Differential resource selection within shared habitat types across spatial scales in sympatric toads

Ecology ◽  
2009 ◽  
Vol 90 (12) ◽  
pp. 3430-3444 ◽  
Author(s):  
Lukas Indermaur ◽  
Thomas Winzeler ◽  
Benedikt R. Schmidt ◽  
Klement Tockner ◽  
Michael Schaub
2014 ◽  
Vol 92 (3) ◽  
pp. 239-249 ◽  
Author(s):  
Antoine St-Louis ◽  
Steeve D. Côté

Herbivores foraging in arid and seasonal environments often face choices between plant patches varying in abundance and nutritional quality at several spatial and temporal scales. Because of their noncompartmented digestive system, equids typically rely on abundant forage to meet their nutrient requirements. In forage-limited environments, therefore, scarcity of food resources represents a challenge for wild equids. We investigated hierarchical resource-selection patterns of kiangs (Equus kiang Moorcroft, 1841), a wild equid inhabiting the high-altitude steppes of the Tibetan Plateau, hypothesizing that vegetation abundance would be the main factor driving resource selection at a large scale and that plant quality would influence resource selection at finer scales. We investigated resource-selection patterns at three spatial levels (habitat, feeding site, and plant (vegetation groups, i.e., grasses, sedges, forbs, and shrubs)) during summer and fall. At the habitat level, kiangs selected both mesic and xeric habitats in summer and only xeric habitats (plains) during fall. At the feeding-site level, feeding sites had higher plant biomass and percentage of green foliage than random sites in the same habitats. At the plant level, grasses were selected over forbs and shrubs, and sedges were used in proportion to their availability during all seasons. Our results indicate that resource-selection patterns in kiangs vary across scales and that both forage abundance and quality play a role in resource selection. Plant quality appeared more important than hypothesized, possibly to increase daily nutrient intake in forage-limited and highly seasonal high-altitude rangelands.


2017 ◽  
Vol 95 (3) ◽  
pp. 203-212 ◽  
Author(s):  
Jared F. Duquette ◽  
Jerrold L. Belant ◽  
Clay M. Wilton ◽  
Nicholas Fowler ◽  
Brittany W. Waller ◽  
...  

The spatial scales at which animals make behavioral trade-offs is assumed to relate to the scales at which factors most limiting resources and increasing mortality risk occur. We used global positioning system collar locations of 29 reproductive-age female black bears (Ursus americanus Pallas, 1780) in three states to assess resource selection relative to bear population-specific density, an index of vegetation productivity, riparian corridors, or two road classes of and within home ranges during spring–summer of 2009–2013. Female resource selection was best explained by functional responses to vegetation productivity across nearly all populations and spatial scales, which appeared to be influenced by variation in bear density (i.e., intraspecific competition). Behavioral trade-offs were greatest at the landscape scale, but except for vegetation productivity, were consistent for populations across spatial scales. Females across populations selected locations nearer to tertiary roads, but females in Michigan and Mississippi selected main roads and avoided riparian corridors, whereas females in Missouri did the opposite, suggesting population-level trade-offs between resource (e.g., food) acquisition and mortality risks (e.g., vehicle collisions). Our study emphasizes that female bear population-level resource selection can be influenced by multiple spatially dependent factors, and that scale-dependent functional behavior should be identified for management of bears across their range.


2002 ◽  
Vol 53 (6) ◽  
pp. 999 ◽  
Author(s):  
B. J. Robson ◽  
E. T. Chester ◽  
L. A. Barmuta

A method is described for making rapid in situ field measurements of riverbed topography over spatial scales of ≅1–10 m. This method uses rolling balls to make quick, accurate measurements of river-bed roughness at several spatial scales. Random sampling and replication generate multiple estimates of the fractal dimension (d) that can be used to test for significant differences in the complexity of riverbed architecture between habitat types and spatial scales.


2018 ◽  
Vol 8 (21) ◽  
pp. 10569-10577 ◽  
Author(s):  
Thomas A. Verschut ◽  
Brian D. Inouye ◽  
Peter A. Hambäck

Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 434
Author(s):  
Linda Eggertsen ◽  
Whitney Goodell ◽  
César A. M. M. Cordeiro ◽  
Thiago C. Mendes ◽  
Guilherme O. Longo ◽  
...  

Spatial configuration of habitat types in multihabitat seascapes influence ecological function through links of biotic and abiotic processes. These connections, for example export of organic matter or fishes as mobile links, define ecosystem functionality across broader spatial scales. Herbivory is an important ecological process linked to ecosystem resilience, but it is not clear how herbivory relates to seascape configuration. We studied how herbivory and bioerosion by 3 species of parrotfish were distributed in a multi-habitat tropical seascape in the Western Indian Ocean (WIO). We surveyed the abundance of three species with different life histories—Leptoscarus vaigiensis (seagrass species), Scarus ghobban (juvenile-seagrass/adults-reefs) and Scarus rubroviolaceus (reef species) —in seagrass meadows and on reefs and recorded their selectivity of feeding substrate in the two habitats. Herbivory rates for L. vaigiensis and S. ghobban and bioerosion for S. rubroviolaceus were then modelled using bite rates for different size classes and abundance and biomass data along seascape gradients (distance to alternative habitat types such as land, mangrove and seagrass). Bioerosion by S. rubroviolaceus was greatest on reefs far from seagrass meadows, while herbivory rates by S. ghobban on reefs displayed the opposite pattern. Herbivory in seagrass meadows was greatest in meadows close to shore, where L. vaigiensis targeted seagrass leaves and S. ghobban the epiphytes growing on them. Our study shows that ecological functions performed by fish are not equally distributed in the seascape and are influenced by fish life history and the spatial configuration of habitats in the seascape. This has implications for the resilience of the system, in terms of spatial heterogeneity of herbivory and bioerosion and should be considered in marine spatial planning and fisheries management.


2016 ◽  
Vol 43 (3) ◽  
pp. 267 ◽  
Author(s):  
Nader Habibzadeh ◽  
Omid Rafieyan

Context To create management strategies with the goal of sustaining a species such as Caucasian grouse (Lyrurus mlokosiewiczi), it is important to identify the habitat requirements of species, not just in terms of a correlation with a given habitat feature, but also the relationship between species presence and vegetation coverage, proximity to other habitat types, and importance at different spatial scales. Aims To predict the proportions and spatial configuration of major habitat types that are associated with high probabilities of Caucasian grouse lek occurrence. Methods Using minimum mapping-unit scale (i.e. grain) for land cover, we applied spatial analysis at three spatial extents (472-, 702- and 867-m-radius circles) to assess how the importance of different land-cover patterns and patch characteristics surrounding leks of Caucasian grouse changed with scale within the Arasbaran landscape (316.56 km2) in East Azerbaijan, Iran. A set of a priori models has been developed on the basis of landscape metrics linked to hypotheses that could explain the spatial pattern of Caucasian black habitat use at each scale. We used an information-theoretic approach based on Akaike’s information criterion (AIC) within a general additive models framework to model habitat selection, so as to compare the values of landscape metrics calculated for Caucasian grouse lek sites (n = 22) with those calculated for non-lek points (n = 44). Key results The probability of lek occurrence at each of the spatial scales increases with a larger amount of open, young forests in the landscape. At each scale, we could indicate the landscape composition and structure required to create an ideal habitat mosaic for Caucasian grouse. Such an ideal habitat mosaic within mountain forests of Arasbaran, for a 702-m-radius area around a potential lek site, would consist of non-square (i.e. more geometrically complex) patches of rangeland cover and deciduous stands with canopy cover of <50%, which encompass over 30% of landscape. Conclusions Our results identified differences in black grouse requirements at several scales within the landscape. We believe this will help managers improve the habitat focusing on the area around existing or inactive leks, to adapt the landscape to species requirements, and to encourage targeting new sites. Implications These findings demonstrated that not only can we identify important landscape requirements at a range of scales, but by characterising landscape composition and structure across these scales, forest managers can help prioritise combinations of habitats that best serve the conservation of the target species.


2007 ◽  
Vol 88 (3) ◽  
pp. 614-624 ◽  
Author(s):  
Deborah A. Jenkins ◽  
James A. Schaefer ◽  
Rick Rosatte ◽  
Tim Bellhouse ◽  
Josef Hamr ◽  
...  

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 176
Author(s):  
Alexander R. Ilich ◽  
Jennifer L. Brizzolara ◽  
Sarah E. Grasty ◽  
John W. Gray ◽  
Matthew Hommeyer ◽  
...  

The west Florida shelf (WFS; Gulf of Mexico, USA) is an important area for commercial and recreational fishing, yet much of it remains unmapped and unexplored, hindering effective monitoring of fish stocks. The goals of this study were to map the habitat at an intensively fished area on the WFS known as “The Elbow”, assess the differences in fish communities among different habitat types, and estimate the abundance of each fish taxa within the study area. High-resolution multibeam bathymetric and backscatter data were combined with high-definition (HD) video data collected from a near-bottom towed vehicle to characterize benthic habitat as well as identify and enumerate fishes. Two semi-automated statistical classifiers were implemented for obtaining substrate maps. The supervised classification (random forest) performed significantly better (p = 0.001; α = 0.05) than the unsupervised classification (k-means clustering). Additionally, we found it was important to include predictors at a range of spatial scales. Significant differences were found in the fish community composition among the different habitat types, with both substrate and vertical relief found to be important with rock substrate and higher relief areas generally associated with greater fish density. Our results are consistent with the idea that offshore hard-bottom habitats, particularly those of higher vertical relief, serve as “essential fish habitat”, as these rocky habitats account for just 4% of the study area but 65% of the estimated total fish abundance. However, sand contributes 35% to total fish abundance despite comparably low densities due to its large area, indicating the importance of including these habitats in estimates of abundance as well. This work demonstrates the utility of combining towed underwater video sampling and multibeam echosounder maps for habitat mapping and estimation of fish abundance.


Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2334
Author(s):  
James T. Johnson ◽  
Richard B. Chandler ◽  
L. Mike Conner ◽  
Michael J. Cherry ◽  
Charlie H. Killmaster ◽  
...  

Bait is often used to increase wildlife harvest susceptibility, enhance viewing opportunities, and survey wildlife populations. The effects of baiting depend on how bait influences space use and resource selection at multiple spatial scales. Although telemetry studies allow for inferences about resource selection within home ranges (third-order selection), they provide limited information about spatial variation in density, which is the result of second-order selection. Recent advances in spatial capture-recapture (SCR) techniques allow exploration of second- and third-order selection simultaneously using non-invasive methods such as camera traps. Our objectives were to describe how short-term baiting affects white-tailed deer (Odocoileus virginianus) behavior and distribution. We fit SCR models to camera data from baited and unbaited locations in southwestern Georgia to assess the effects of short-term baiting on second- and third-order selection of deer during summer and winter surveys. We found little evidence of second-order selection during late summer or early winter surveys when camera surveys using bait are typically conducted. However, we found evidence for third-order selection, indicating that resource selection within home ranges is affected. Concentrations in space use resulting from baiting may enhance disease transmission, change harvest susceptibility, and potentially bias the outcome of camera surveys using bait.


2012 ◽  
Vol 39 (5) ◽  
pp. 408 ◽  
Author(s):  
J. E. Paterson ◽  
B. D. Steinberg ◽  
J. D. Litzgus

Context Turtles are one of the most imperilled taxonomic groups worldwide and information about population ecology is essential to species recovery. Although the spatial ecology and demography of adults of several turtle species have been well studied, little is known about early life stages. The small size, soft shell, and limited mobility of hatchling turtles may cause differences in survivorship and habitat selection compared with adults. Aims We tested the hypothesis that hatchling turtles select habitat as they move away from nests, so as to reduce the risk of predation and desiccation. Methods We examined survivorship, behaviour and habitat selection at two spatial scales in hatchling Blanding’s turtles (Emydoidea blandingii) and wood turtles (Glyptemys insculpta) in 2009 and 2010, using radio-telemetry in Algonquin Provincial Park, Ontario, Canada. In addition, temperatures of sites used by hatchlings during winter were compared with those at haphazard stations in various habitats. Key results The mortality rate was high, with 42% of E. blandingii and 11% of G. insculpta hatchlings surviving to winter; most mortality was caused by predation. Most behavioural observations for both species were of individuals hiding under cover. Both species showed evidence of macrohabitat and microhabitat selection as they dispersed from nests towards overwintering sites, and important variables in the models differed between species. Likewise, the adult stages of these two species differ in their macrohabitat specialisation. There was also evidence that hatchlings chose overwintering sites on the basis of temperature. Conclusions Despite significant differences in survivorship between hatchlings and adults, resource selection was similar between these two demographic stages, and conservation plans based on adult habitat use should simultaneously protect hatchlings. Implications Understanding habitat selection by juveniles is important for testing hypotheses about ontogenetic shifts in resource selection and for protecting habitat for species at risk.


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