Selection Of Cover Types Research Articles

Foraging habitat selection and differentiation among coexisting raptors across an estuarine landscape (Evros Delta, northern Greece)

Knowledge of habitat preferences is critical for understanding the needs of and interactions among sympatric avian species and for implementing successful management and conservation projects. The common buzzard, western marsh harrier, hen harrier and black kite are the commonest raptors of Greece during the non-breeding season. Therefore, the availability, use and selection of cover types by these foraging raptors were recorded in the Evros Delta, Greece, along a 40-km x 1-km road transect, using the road transect method. A total of 14 surveys (2–4 a month) were conducted during the non-breeding season, from November 2002 to March 2003. Eight cover types were identified within the transect, with agricultural land being the most abundant, followed by saltmarshes, freshwater marshes and lagoons. Each raptor species was more likely to use one or more cover types more than expected and other types less than expected. Overlap in cover type use was higher between common buzzards, western marsh harriers and black kites, and lower between these species and hen harriers. Common buzzards more strongly selected freshwater marshes, rivers and canals, grassland and reedbeds as foraging habitats. Foraging western marsh harriers more strongly selected reedbeds, freshwater marshes and saltpans, hen harriers mostly preferred grassland and saltmarshes, whereas black kites showed a strong selection for rivers and canals, freshwater marshes and reedbeds. Analysis revealed preferences, similarities and differences in habitat use and selection among four diurnal medium-sized raptors across the Evros Delta. Particularities in habitat preferences by raptors suggested that they were adapted to the available features in this area. This study provided important information on the foraging behavior of raptor species that could help assess the importance of certain sites and habitats and improve management strategies to benefit birds.

Home Range and Habitat Selection by Northern Spotted Owls on the Eastern Slope of the Cascade Mountains, Washington

Abstract We used radiotelemetry to study space use and habitat selection of 16 Northern Spotted Owls (Strix occidentalis caurina) on the eastern slope of the Cascade Mountains, Washington, U.S.A., in 1989–1990. We used a geographical information system (GIS) and aerial photo interpretation of digital orthophotos to assign owl locations a value for vegetation type, topographic position, amount of edge, and distance to water. We compared owl relocations and random locations within 95% fixed kernel (FK) home ranges to determine each owl's selection of cover types, using logistic regression and generalized estimating equations (GEE) to estimate an exponential resource selection function likelihood. Minimum convex polygon (MCP) home ranges (SE) averaged 2858 ha (712 ha) for males and 1883 ha (249 ha) for females. Individual 95% FK home ranges averaged 1980 ha (229 ha) for males and 1649 ha (163 ha) for females. Pair home ranges averaged 3419 ha (826 ha) for MCP and 2427 ha (243 ha) for 95% FK. Nonbreeding seas...

Movements, cover-type selection, and survival of fledgling Ovenbirds in managed deciduous and mixed coniferous-deciduous forests

We used radio telemetry to monitor movements, cover-type selection, and survival for fledglings of the mature-forest nesting Ovenbird (Seiurus aurocapilla) at two managed forest sites in north-central Minnesota. Both sites contained forested wetlands, regenerating clearcut stands of various ages, and logging roads, but differed in mature forest composition; one deciduous with open understory, and the other mixed coniferous-deciduous with dense understory. We used compositional analysis, modified to incorporate age-specific limitations in fledgling movements, to assess cover-type selection by fledglings throughout the dependent (on adult care) post-fledging period. Compared to those that were depredated, fledglings from nests in deciduous forest that survived the early post-fledging period had more older (sapling-dominated) clearcut available, directed movements toward older clearcuts and forested wetlands, and used older clearcuts more than other cover types relative to availability. Fledglings that were depredated had more young (shrub-dominated) clearcut and unpaved logging road available, and used mature forest and roads more than expected based on availability. For birds from nests in mixed mature forest with dense understory, movements and cover-type selection were similar between fledglings that survived and those that were depredated. However, fledglings that were depredated at that site also had more young clearcut available than fledglings that survived. We conclude that Ovenbird fledgling survival is influenced by distance of their nest to various non-nesting cover types, and by the subsequent selection among those cover types, but that the influence of non-nesting cover types varies depending on the availability of dense understory vegetation in mature forest.

Movement and Cover-type Selection by Fledgling Ovenbirds (Seiurus aurocapilla) after Independence from Adult Care

We used radiotelemetry to monitor movements and cover-type selection by independent fledgling Ovenbirds (Seiurus aurocapilla) at two managed-forest sites differing in mature-forest matrix: open-understory deciduous forest and dense-understory mixed-deciduous-conifer forest. Ovenbirds at each site made one to three single-day long-distance movements; those movements were of similar distance at the deciduous site ( = 849 ± 159 m) and the mixed-deciduous-conifer site ( = 1,133 ± 228 m). They also moved similar mean daily distances within stands at the deciduous site ( = 101 ± 12 m) and the mixed-deciduous-conifer site ( = 105 ± 11 m), and used areas of similar local vegetation density, but denser than that of their nesting habitat. Fledglings in the deciduous study area selected sapling-dominated clearcuts and forested wetlands over mature forest and shrub-dominated clearcuts. Fledglings in the mixed-deciduous-conifer study area generally used cover types in accordance with availability, and tended not to use shrub-dominated clearcuts. Our results suggest regenerating clearcuts may be important areas for independent fledgling Ovenbirds in landscapes that consist of otherwise contiguous open-understory mature forest, but not until saplings establish in those clearcuts, and not necessarily in forests where dense understory and naturally dense areas such as forested wetlands are common.

Effects of Time of Day and Activity Status on Bobcat (Lynx rufus) Cover-Type Selection in Southwestern Georgia

Lynx rufus (Bobcat) cover-type selection and activity patterns have been studied in a variety of landscapes in the southeastern United States, but effects of individual activity status (active or inactive) and time of day (day, night, crepuscular) on cover-type selection have not been investigated for this species. Therefore, we investigated Bobcat habitat use in a Pinus palustris (Longleaf Pine) forest in southwestern Georgia to determine whether activity status of individuals or time of day affected seasonal cover-type selection. We monitored 43 radiocollared Bobcats from 2001–2004 and determined habitat use at Johnson's third order of selection (i.e., habitat selection within the home range) using Euclidean distance-based analysis. Bobcats selected (Λ; = 0.017, P = 0.001) habitat within their home ranges; however, although Bobcats are typically classified as crepuscular, neither activity status (Λ; = 0.990, P = 0.981) nor time-of-day (Λ; = 0.972, P = 0.647) affected cover-type selection. Bobcats on our study site preferred agricultural areas and other early to mid-successional habitats, probably because they produced abundant prey.

Winter Home-range Characteristics of American Marten (Martes Americana) in Northern Wisconsin

We estimated home-range size for American marten (Martes americana) in northern Wisconsin during the winter months of 2001–2004, and compared the proportion of cover-type selection categories (highly used, neutral and avoided) among home-ranges (95% fixed-kernel), core areas (50% fixed-kernel) and the study area. Average winter home-range size was 3.29 km2 with home-ranges of males (n = 8, mean = 4.25 km2) significantly larger than females (n = 5, mean = 2.32 km2). Composition of cover-type selection categories in home-ranges differed significantly from what was available in the study area (X2 = 6.9145, df = 2, P > 0.0315) with more highly used habitat and less avoided habitat than expected. Consistent with research in other regions, 72% of an American marten home-range contained highly used cover-types and 18% of a home-range contained avoided types with the remainder of the average home-range composed of neutral cover-types. This suggests that Wisconsin American martens select habitat at the home-range scale based on the occurrence of highly used and avoided cover types. Proportions of selection categories in core areas did not differ significantly from what was available in the study area or in home-ranges. Core areas were significantly smaller than home-ranges and this observation combined with the lack of cover-type selection at the core area scale suggests that American martens select core areas based upon micro-site features (e.g., rest sites) rather than broad-scale cover types. The findings presented here may assist wildlife managers in management activities by identifying potentially suitable habitat.

Predator Selection of Prairie Landscape Features and Its Relation to Duck Nest Success

Mammalian predation is a major cause of mortality for breeding waterfowl in the U.S. Northern Great Plains, and yet we know little about the selection of prairie habitats by predators or how this influences nest success in grassland nesting cover. We selected 2 41.4-km 2 study areas in both 1996 and 1997 in North Dakota, USA, with contrasting compositions of perennial grassland. A study area contained either 15-20% perennial grassland (Low Grassland Composition LGC]) or 45-55% perennial grassland (High Grassland Composition [HGC]). We used radiotelemetry to investigate the selection of 9 landscape cover types by red fox (Vulpes vulpes) and striped skunk (Mephitis mephitis), while simultaneously recording duck nest success within planted cover. The cover types included the edge and core areas of planted cover, wetland edges within planted cover or surrounded by cropland, pastureland, hayland, cropland, roads, and miscellaneous cover types. Striped skunks selected wetland edges surrounded by agriculture over all other cover types in LGC landscapes (P-values for all pairwise comparisons were <0.05). Striped skunks also selected wetland edges surrounded by agriculture over all other cover types in HGC landscapes (P < 0.05), except for wetland edges within planted cover (P = 0.12). Red foxes selected the edge and core areas of planted cover, as well as wetland edges within planted cover in LGC landscapes (i.e., they were attracted to the more isolated patches of planted cover). However, in HGC landscapes, red foxes did not select interior areas of planted cover (i.e., core areas of planted cover and wetland edges in planted cover) as frequently as edges of planted cover (P< 0.05). Red foxes selected core areas of planted cover more frequently in LGC than in HGC landscapes (P< 0.05) and selected pastureland more frequently in HGC than in LGC landscapes (P< 0.05). Furthermore, red foxes selected the isolated patches of planted cover more than pastureland in LGC landscapes (P< 0.05). Duck nest success was greater in HGC landscapes than in LGC landscapes for planted-cover core (P < 0.0001), planted-cover edge (P< 0.001) and planted cover-wetland edge (P< 0.001). Both the increased amount of planted-cover core area and the increased pastureland selection in HGC landscapes may have diluted predator foraging efficiency in the interior areas of planted cover and contributed to higher nest success in HGC landscapes. Our observations of predator cover-type selection not only support the restoration and management of large blocks of grassland but also indicate the influence of alternative cover types for mitigating nest predation in the Prairie Pothole Region.

A MULTISCALE BEHAVIORAL APPROACH TO UNDERSTANDING THE MOVEMENTS OF WOODLAND CARIBOU

We assessed the response of woodland caribou (Rangifer tarandus caribou) to land-cover type, predation risk, energetic costs of movement, and patch configuration at multiple spatial scales. We applied a nonlinear model to frequent locations collected with Global Positioning System (GPS) collars to identify discontinuities in the scales of movement by caribou found in forested and alpine (above tree line) habitats. We differentiated intra- from interpatch movements and identified collections of patches (multiple-patch scale) where caribou concentrated intrapatch movements. On average, intra- and interpatch movements were 450.7 and 1268.8 m, respectively, and multiple-patch movements occurred over an area of 182 ha. Intrapatch movements were highly correlated, indicative of a strong relationship between behavior and place. Caribou in the forest selected patches of Pine terrace, whereas caribou in the alpine selected patches of Alpine-little vegetative cover. Predation risk was not a factor influencing movements of caribou at the intrapatch scale. Selection of cover types was more variable during interpatch movements. At that scale, caribou selected patches of Pine terrace, Lakes/rivers, Alpine-little vegetative cover, and Alpine-grass. The routes selected by caribou had lower energetic costs relative to surrounding terrain, and during some winters, caribou were subjected to higher levels of predation risk during those movements. At the multiple-patch scale, selection was more specific and encompassed patches of Alpine-little vegetative cover, Alpine-grass, and Pine terrace. Predation risk was relatively unimportant at the multi-patch scale, but animals that moved from forested to alpine habitats reduced their relative risk of predation. Patch configuration was a poor predictor of those areas where caribou concentrated intrapatch movements. There was some evidence of caribou selecting patches of Pine terrace within a matrix of Wetlands and Pine–black spruce/black spruce patches. Caribou in the alpine avoided patches of Alpine-little vegetative cover adjacent to forest types. Our results indicate that forest managers should maintain widely distributed patches of Pine terrace and implement silvicultural regimes that do not stimulate predator populations across areas used for interpatch movements.

Habitat use and survival of northern bobwhite (Colinus virginianus) in cropland and rangeland ecosystems during the hunting season

Many researchers and managers believe that land-use practices are most responsible for declines in northern bobwhite (Colinus virginianus) populations. Additionally, researchers have suggested that the amount of available escape cover in a landscape could alter winter survival of bobwhites. A comparative study of winter bobwhite ecology was conducted on rangeland and cropland ecosystems in east-central Kansas (11 November - 31 January 1993-1996). We considered woody cover type on our study areas to be an escape cover for quail. We used radiotelemetry to investigate survival, movement, and cover-type selection. Over the 3-year period, we monitored 91 individuals on a cropland study area (CSA) and 66 birds on a rangeland study area (RSA). Survival was higher on the CSA (0.46) than on the RSA (0.27) (P = 0.03); the difference was due to increased harvest mortality on the RSA (P = 0.04). Mean daily covey movement was higher on the RSA than on the CSA (P &lt; 0.01). Comparing cover-type selection between study areas, it was found that bobwhites selected cropland more on the RSA than on the CSA (P &lt; 0.01). On the RSA, increased daily movement correlated with decreased selection for woody cover and increased selection for cropland (P &lt; 0.02). On the CSA, increased woody-cover selection decreased natural predation (P = 0.03). On the RSA, decreased movement, increased woody cover, and decreased pasture selection reduced natural predation (P &lt; 0.05). However, increased woody-cover selection increased harvest mortality (P &lt; 0.01). Consequently, we consider the selection for woody cover to be an important variable in bobwhite survival on the RSA. It is suggested that landowners on rangelands could reduce natural mortality by taking advantage of programs available from federal and state governments and nongovernmental organizations, to increase woody cover for bobwhites.

Effect of fluctuating flow and temperature on cover type selection and behaviour by juvenile brown trout in artificial flumes

Effect of fluctuating flow and temperature on cover type selection and behaviour by juvenile brown trout in artificial flumes

Effect of fluctuating flow and temperature on cover type selection and behaviour by juvenile brown trout in artificial flumes

Brown troutSalmo truttain a flume used cover more often and were more aggregated at low water temperatures in winter compared with summer. Cover combinations providing the most cover (overhead, visual and velocity cover) were preferred in winter whereas velocity refuges were preferred in late summer; and brown trout rarely used any of these cover structures in early summer. Flow affected cover use especially in winter, when most of the trout moved to shelters during the first high flow period. Movements by brown trout were most frequent in early summer. The much higher aggression rate in summer compared with winter decreased during the first period of high flow in both summer experiments. The results indicate seasonal changes in cover habitat and cover type preferences suggesting that habitat complexity is important, and availability of cover is particularly important during different seasons and fluctuating flow.

Habitat use and survival of northern bobwhite (&lt;i&gt;Colinus virginianus&lt;/i&gt;) in cropland and rangeland ecosystems during the hunting season

Many researchers and managers believe that land-use practices are most responsible for declines in northern bobwhite (Colinus virginianus) populations. Additionally, researchers have suggested that the amount of available escape cover in a landscape could alter winter survival of bobwhites. A comparative study of winter bobwhite ecology was conducted on rangeland and cropland ecosystems in east-central Kansas (11 November - 31 January 1993-1996). We considered woody cover type on our study areas to be an escape cover for quail. We used radiotelemetry to investigate survival, movement, and cover-type selection. Over the 3-year period, we monitored 91 individuals on a cropland study area (CSA) and 66 birds on a rangeland study area (RSA). Survival was higher on the CSA (0.46) than on the RSA (0.27) (P = 0.03); the difference was due to increased harvest mortality on the RSA (P = 0.04). Mean daily covey movement was higher on the RSA than on the CSA (P < 0.01). Comparing cover-type selection between study ar...

Effects of Moose Movement and Habitat Use on GPS Collar Performance

We tested a radiotelemetry collar that uses a Global Positioning System (GPS) unit to calculate animal locations. We placed the collar in a range of cover types and compared locations reported by the collar to differentially-corrected GPS locations. We placed the collar on a free-ranging moose (Alces alces) and determined how selection of cover types, collar movement, and collar orientation affected GPS locations. On or off the moose, the GPS unit collected a location in >90% of location attempts in areas with no or thin canopy cover, including mature deciduous canopies in winter. Under a mature conifer canopy or a mature deciduous canopy in summer, 60 to 70% of location attempts were successful. Locations from the GPS unit in the collar were close to the expected precision of non-differentially corrected GPS (within 40 m 50% of the time and 100 m 95% of the time). Locations did not have a directional bias. Movement of the moose while a location was being attempted did not affect GPS locations. The moose occasionally laid down so the collar was horizontal. Although this decreased the success of location attempts, <1% of location attempts were so affected. GPS radiotelemetry has great promise for expanding our knowledge about hourly, daily, and annual patterns in animal movements and habitat selection.