Habitat use by three rat species (

Ship rats (Rattus rattus) were removed from sites on Pearl Island, southern Stewart Island, in 2004 and 2005, to test whether they excluded Pacific rats (R. exulans) or Norway rats (R. norvegicus) or both from podocarp-broadleaf forest. As predators can influence habitat use in rodents, Pearl Island was selected because no mammalian predators of rodents are present. Rats were trapped in two other habitats to clarify rat distribution on the island and to obtain samples for stable isotope investigation of food partitioning within habitats. The experimental removal of ship rats failed, as Pacific rats were found to share forest and shrubland with ship rats. This result contrasted with the restricted distribution of Pacific rats on Stewart Island. Ship rats were ubiquitous, and appear to have been the dominant species in podocarp-broadleaf forest on Pearl Island. The largest species, the Norway rat, was trapped only on the foreshore of Pearl Island, but on Stewart Island it is more widespread. Ship rats and Norway rats were partitioning the coastal habitat by exploiting different food sources. Stable isotopic ratios (δ¹⁵N and δ¹³C) in muscle samples from Norway rats revealed a strong marine signature, suggesting intensive foraging in the intertidal zone. Ship rats trapped in the same habitat exhibited mixed terrestrial and marine sources in their diet. There was little obvious partitioning between ship rats and Pacific rats in forest, except a possible delay in breeding in Pacific rats relative to ship rats. Whether Norway rats select the intertidal zone to forage, or were excluded from forest by ship rats is unknown, but competitive exclusion is likely. Estimated densities of rats were low (2.1–5.1 rats ha^-1 in forest, 1.42 rats ha^-1 in shrubland) and similar to other New Zealand sites with low soil fertility. Further research will be required to elucidate the roles of food quality, habitat structure and predation in facilitating habitat selection in these species.     

Habitat use by five sympatric Australian freshwater crayfish species (Parastacidae)

1. The Grampians National Park in Victoria is a ‘hot spot’ for freshwater crayfish diversity, with seven species from six genera occurring in sympatry. Few studies have examined how multiple species of freshwater crayfish co‐exist across landscapes consisting of a mosaic of perennial and seasonal habitats. Despite their endemicity and likely key role in freshwaters, the ecology and biology of these crayfish remains unknown. 2. This study determined the distribution and habitat use of five crayfish species (Euastacus bispinosus, Cherax destructor, Geocharax falcata, Gramastacus insolitus and Engaeus lyelli). Seasonal sampling surveys ascertained whether crayfish distribution was related to habitat type, environmental or physicochemical variables, catchment or season. 3. Distribution was directly related to habitat type and the environmental and physicochemical variables that characterised habitats. Engaeus lyelli, G. falcata and G. insolitus occurred predominantly in floodplain wetlands and flooded vegetation habitats, E. bispinosus occurred only in flowing soft‐sediment channels and C. destructor was found in all catchments and habitat types studied. Gramastacus insolitus co‐occurred with G. falcata at all sites except two, so no distinct habitat separations were apparent for these two species. 4. A high percentage cover of boulders was the best indicator of crayfish absence, and discriminated between habitat types and crayfish species: it was probably a surrogate for a larger range of environmental and physicochemical variables. Catchment and season did not affect crayfish distribution. 5. These crayfish species varied in their degree of habitat specialisation from strongly generalist (C. destructor) to occupying only a specific habitat type (E. bispinosus). Some species appeared specialised for seasonal wetlands (G. insolitus and G. falcata). Overlap in site occupancy also varied: G. insolitus and G. falcata distributions were strongly associated, whereas C. destructor appeared to occur opportunistically across habitats, both alone and co‐occurring with all the other species. 6. Management strategies to conserve multiple species of crayfish co‐existing within landscapes will need to incorporate a range of perennial and seasonal habitat types to ensure sufficient space is available for species to maintain different occupancy patterns. Given that water resources are under increasing pressure and are strongly regulated within the Grampians National Park, this may present a conservation challenge to water managers in this location.     

Habitat use by chevron skinks (

Habitat use of the endangered chevron skink (Oligosoma homalonotum) was investigated between 1997 and 2002 at three sites on Great Barrier Island, New Zealand. Habitat preferences were determined by pitfall trapping and radio-tracking studies, and a comparison of catchments with and without chevron skinks. Over the course of the research, 88 skinks were encountered. Significantly more skinks were caught in pitfall traps set in stream habitat than in alluvial terrace, boulder bank or ridge habitat. Eight chevron skinks were radio-tracked for periods between three and eight days, and 118 fixes were taken from 55 different retreat sites. When compared with randomly selected sites, chevron skinks were more likely to be found at sites that had crevices, debris dams and trees than those that did not. The further a site was away from the stream edge, the less likely it was to be a chevron skink retreat site. Chevron skinks were more likely to be found in catchments with narrow streams with rocky, as opposed to silty, substrates. We recommend that future management of chevron skinks incorporate sites that contain mature forest and rocky streams. While forest habitats on Great Barrier Island appear to be increasing in area, chevron skinks may still be declining due to the effects of introduced predators.     

Habitat use by triplefin species (Tripterygiidae) on rocky reefs in New Zealand

Habitat use and nesting sites of 12 triplefin species (Tripterygiidae) were investigated at 26 coastal and offshore rocky reef locations in north-eastern New Zealand. Within these locations, 17 broad-scale habitats and 14 fine-scale habitats were surveyed using visual transects. In terms of broad-scale habitat use, four species, Notoclinops segmentatus , Forsterygion lapillum , Forsterygion varium and Ruanoho whero showed a high similarity in distribution, irrespective of depth or habitat characteristics. The distributions of Bellapiscis lesleyae , Cryptichthys jojettae and Ruanoho decemdigitatus were relatively similar, being primarily confined to shallow habitats providing a high degree of shelter. Forsterygion flavonigrum , Forsterygion malcolmi and Notoclinops caerulepunctus were all predominantly found beyond 10 m, irrespective of habitat characteristics. Despite the majority of species using several distinct fine-scale habitats, a high degree of variation was apparent between species, with the majority of species showing extremely low overlap of fine-scale habitats used. Differences in fine-scale habitat use were not apparent when comparing the nesting sites of species. All nests were found in fine-scale habitats, presumably affording a high degree of shelter from predation and physical disturbance. Interspecific partitioning of spatial resources probably occurs by depth and microhabitat in this species assemblage in north-eastern New Zealand.     

Habitat requirements and local persistence of three damselfly species (odonata: coenagrionidae)

Habitat requirements and population persistence were investigated in three damselfly species, all coastal plain pond specialists: Enallagma recurvatum, E. laterale, and E. pictum. Because of geographic restriction, two are of special concern to conservation, E. recurvatum and E. laterale. We surveyed more than 70 ponds on Cape Cod, Massachusetts, and collected adult presence-absence data during the summers of 1999 and 2000. We achieved a detection rate approaching 100% for each species by visiting each pond up to three times. We looked for relationships between the presence of each damselfly species and presence of specific aquatic vegetation, the presence of the other Enallagma species, and the number of ponds within various distances of the 72 surveyed ponds. Using stepwise logistic regression, we found the following significant associations: E. recurvatum with the rush Juncus militaris; E. laterale with water lilies (Nuphar variegatum and Brasenia schreberi) the damselfly E. pictum, and the number of ponds within 2 km; and E. pictum with the water lily Nymphaea odorata, the damselfly E. laterale, and the number of ponds within 1.5 km and 2.5 km. Presence-absence data were used to calculate turnover and local extinction rates for each species between the two years. E. recurvatum's turnover and local extinction rates (33.3% and 41% respectively) were much higher than either E. laterale (9.8%, 11.5%) or E. pictum (7.7%, 10%). These results suggest that E. recurvatum occurs in a metapopulation, and that patch colonization rates might be important to local population persistence.     

Habitat selection of three chrysomelid species associated with Rumex spp.

Summary Habitat selection of three chrysomelid beetles feeding on the Rumex plants was studied in relation to the ecological requirements of the three species and the habitat characteristics arising in their unstable and often unpredictable environment. The different ecological requirements and bionomic characteristics of the three chrysomelids were associated not only with their differing degrees of feeding specialization; they also influenced habitat selection. For example, the small body size and lower food demands of Mantura clavareaui, which is a feeding specialist, allowed it to exploit any habitat, irrespective of habitat size and duration. The other specialist, Gastrophysa atrocyanea, selected larger habitats because of the relatively brief lifespan of its adults after overwintering, its reduced mortality, and greater food demand. On the other hand, Galerucella vittaticollis, which is a multivoltine, general feeder, selected the habitat that lasted longer, rather than one that was larger. This species' life cycle is not synchronized with Rumex phenology, but its adults are long-lived and it has a flexible life cycle. The different patterns in habitat selection among these three chrysomelids prevented serious overlapping of their habitats; thus, the habitat overlapping of 2 or 3 species was 34.62%, that of all 3 species 3.85%. Most of the habitats utilized by Gastrophysa, however, overlapped those of the other two species, because Gastrophysa's habitat utilization range was the narrowest of the three. In Mantura, the degree of overlap with the other two species was lowest because this beetle had the broadest range of habitat utilization. On the other hand, Galerucella adjusted the temporal, rather than the spatial coordinates of its habitat usage when it occupied habitats where the other two specialists were also present. Galerucella, unlike the other two species, is multivoltine. Consequently, it was able to coexist in habitats occupied by the others by exploiting the host plants at times when the other species were numerically few, or even absent. No direct interspecific competition among adults of the three species was observed. Their different patterns of habitat selection created by their different responses to available food allowed them to coexist on Rumex without direct competition.     

Habitat partitioning by whiting species (Sillaginidae) in coastal waters

Synopsis The ways in which the distributions of six species of whiting (Sillaginidae) in the coastal marine waters of south-western Australia are related to the type of substrate (bare sand vs. seagrass), degree of exposure of habitat, water depth and body size have been investigated. Whiting in near shore waters (< 1.5 m) were sampled using a fine-meshed seine net, while those in shallow (5–15 m) and deep (20–35 m) waters of the inner continental shelf were sampled with a trawl net. Shallow nearshore waters are shown to provide nursery habitats for five of the six whiting species. In these waters, Sillaginodes punctata, Sillago burrus, Sillago schomburgkii and Sillago vittata mainly occur in protected areas, while Sillago bassensis predominantly occupies areas that are more exposed to wave and swell activity. The first three of these species also use estuaries as nursery areas. In nearshore waters, whiting were captured almost exclusively over bare sand, rather than in interpersed beds of the seagrass Posidonia spp., presumably reflecting the fact that the dense canopies produced by the wide blades of Posidonia spp. must inhibit penetration by the benthic whiting species. As 0 + S. punctata increase in size, they tend to move offshore during the day and inshore at night. Many mature representatives of S. schomburgkii are present in nearshore areas, whereas the other four species move offshore into inner-shelf waters as they increase in length. Sillago burrus and S. vittata remain in shallow inner-shelf waters, whereas the larger S. bassensis subsequently migrate into deeper inner-shelf waters. Large Sillago bassensis thus co-occurs with Sillago robusta, which is mainly found in those deeper waters, but does not reach as large a size. The larger S. punctata occupy areas near reefs which could not be sampled by trawl netting. There are thus interspecific differences in (i) the times of recruitment of the 0 + age class into nearshore areas, (ii) the types of habitat occupied during juvenile and adult life, and (iii) the degree to which fish move into more offshore waters as they increase in length, and one species is restricted to deeper waters. The resultant partial segregation among habitats of the coastal waters of south-western Australia by different size groups of these relatively abundant whiting species presumably reduces the potential for intra- and interspecific competition amongst these species.     

Habitat fragmentation and the prevalence of parasites (Diptera,Streblidae) on three Phyllostomid bat species

Ectoparasitism in bats seems to be influenced strongly by the type of roost preferred by the hosts, and group size; however, the effect of habitat loss and fragmentation on the prevalence of ectoparasites in bats has scarcely been studied. In northeastern Yucatan, Mexico, we estimated the prevalence of infestation by Streblidae flies in three phyllostomid bat species with different roost preferences (caves, trees, or both) in two types of landscape matrices (tropical semi‐deciduous forest and man‐made pastures) that differed in area of forest cover and the number of forest fragments. Habitat fragmentation and the presence of a contrasting matrix may limit the availability of roosts (trees) and the movement of bats across the landscape. Accordingly, we hypothesized higher prevalence of Streblidae infestation in the pasture matrix and in the group of bats that roost in trees. Bat abundance was higher in the pasture matrix; however, the prevalence of infestation was significantly higher in the continuous forest matrix and in bats that roosted in caves. The prevalence of some species of Streblidae was affected by habitat fragmentation in species that roost in caves, such as Desmodus rotundus, as well as those using foliage and caves, such as Artibeus jamaicensis. Our results provide evidence that some species of Streblidae may respond differently to habitat fragmentation than their hosts, generating changes to bat‐ectoparasite interactions in fragmented areas. Environmental variations involving roosts, not evaluated in this study, may influence our results, since these factors affect ectoparasite abundance and reproduction.     

Habitat use and feeding behavior of thirteen species of benthic stream fishes

Synopsis The densities, habitat use, and feeding behaviors of 13 fish species belonging to the benthic invertebrate-feeding guild were studied by snorkeling at three localities in the Little River of eastern Tennessee, U.S.A. Resource partitioning occurred by habitat, feeding behavior and time of activity. Differences were also found at the generic level.Cottus was a nocturnal feeder, whereasPercina andEtheostoma were, for the most part, diurnally active.Percina moved about rapidly and spent most of its time above the bottom. In contrast,Etheostoma varied considerably in the amount of time spent under cover, spent little time above the bottom, and exhibited low levels of swimming activity. Nearly all species sought cover at night, suggesting they may be particularly sensitive to predation at night. Species with small adult sizes (Etheostoma, Cottus andP. evides) were concentrated in shallow water habitats, whereas species with large adult sizes (Percina) were more abundant in deep water habitats. The habitat use data are consistent with the hypothesis that size-selective predation by centrarchid bass may cause smaller fish to avoid deep water areas. Large species should have a lower risk of predation due to their size and behavior.     

Patterns of foraging and range use by three species of neotropical primates

This paper describes the diet and range use patterns of the three species of primates in Santa Rosa National Park, Costa Rica (Ateles geoffroyi, Alouatta palliata, andCebus capucinus) and examines the variation in these variables as they relate to seasonal changes and concomitant changes in food availability. These three primate species were studied over a four-year period for a total of 24 months in the field. Santa Rosa National Park is in an area that experiences a long severe dry season in which little if any rain falls and the majority of the non-riparian trees lose their leaves. However, even though the three species were very flexible in terms of diet and range use, the behavioural variability did not correspond to changes in food availability or season.     

Habitat use by squirrel monkeys (Saimiri oerstedi) in Costa Rica

This paper analyses movement patterns, habitat preferences, activity schedules, and dispersion of troop members in squirrel monkeys (Saimiri oerstedi) in relation to seasonal changes in food abundance in a Costa Rican tropical wet forest. Secondary forest was the preferred habitat and use of primary forest and late successional forest was limited primarily to seasons when food availability was low. Range area differed between seasons, varying from 79 to 110 ha, and totaling 176 ha over 11 months. The number of hectares used, hourly rate of group movement, and proportion of time spent foraging each season were all negatively related to relative food abundance. There was a tendency to spend less time in foraging activities in the middle of the day and to spend more time exclusively in travel at dawn and dusk. In all seasons dispersion was least when the troop was travelling and it was generally greatest during seasons of low food abundance. Measures of the allocation of time by the troop to food-related activities and the extent of troop dispersion each season were consistent with estimates based on behavior sampling of individuals.     

Habitat use by breeding Tree Sparrows Passer montanus

Tree Sparrows Passer montanus showed a strong preference for nest-sites adjacent to wetland habitats, and avoidance of sites on intensively managed mixed farmland distant from Rutland Water. A variety of wetland edge habitats were frequently used by foraging adult birds when provisioning nestlings, and invertebrate prey of aquatic origin was frequently recorded in chick diet. We suggest that the wetland edge habitats at the study sites played a key role in providing adequate diversity and availability of suitable invertebrate prey to allow successful chick rearing throughout the long breeding season of this multi-brooded passerine. It is possible that large areas of formerly occupied farmland in the UK no longer provide these invertebrate resources due to the effects of intensification in the late 20th century. There was no evidence that the availability of supplementary seed food within 1 km of the nest-site influenced nest-site choice, or affected productivity. It is probable that the importance of seed food resources to the persistence of Tree Sparrow populations operates on a larger spatial scale than that tested in this study, due to the greater mobility of Tree Sparrows in the non-breeding season, when seed resources are most likely to be a key limiting factor. When considering conservation management aimed at recovering breeding populations of Tree Sparrows, the key resources of seed food, invertebrate food and nest-sites must be made available at appropriate spatial scales.     

Habitat use by lemmings near Barrow, Alaska

Brown lemmings reach much higher densities than collared lemmings near Barrow, Alaska, and captures from 19 summers of snap trapping confirm previous reports that brown lemmings prefer lower, wetter habitats than do collared lemmings. Data also support the hypothesis that brown lemmings concentrate in higher habitats during early summer when melt water floods lower habitats, then shift to lower habitats where preferred food is more available as the waters recede. This pattern appears similar to seasonal shifts in habitat use reported for Norwegian lemmings. Two hypotheses were not supported by our data: (1) Unlike Norwegian lemmings, brown lemmings did not expand their use of suboptimal habitats at higher population densities. Rather, absolute densities changed in concert so that the relative densities among habitats remained unchanged. (2) Preferential use of polygon troughs during winter, as indicated by patterns of winter grazing, was not simply a function of snow depth. Instead it appeared to be related to shoot density of preferred foods. Nearly all patterns of habitat use seemed to be linked to food availability. Other factors, such as protection from predators by vegetative cover in summer and increased insulation from deeper snow in winter, did not appear to influence the distribution of lemmings as strongly.     

Habitat use by desert bighorn sheep during lambing

Habitat used for predator escape may be a factor limiting restoration of desert bighorn sheep (Ovis canadensis mexicana) in small mountain ranges in New Mexico. Female bighorn sheep seek isolation in discrete areas for parturition. Although parturition sites are used only for <3 days they play an important role in neonate survival. We compared habitat characteristics at pre-parturition (n = 21), parturition (n = 38), random (n = 38), and post-parturition sites (n = 21). At each site we calculated distance to steep terrain, elevation, ruggedness, slope, and visibility. Parturition and post-parturition sites were higher in elevation and more rugged than sites used during pre-parturition. Post-parturition sites were closer to terrain with 100% slope than the pre-parturition or parturition sites. Post-parturition sites had higher visibility and steeper slopes than the pre-parturition sites. Parturition sites were steeper, higher in elevation, more rugged, and had lower visibility than the random sites. Fidelity to parturition sites was observed on 1 of 38 occasions. Because lambing sites are used for short periods they are poorly understood and often ignored by land managers. Additional research is recommended in other desert bighorn sheep populations to understand better and predict habitat use during the lambing period.     

Habitat use by the Grey Heron (Ardea cinerea) in eastern France

We analyzed the spatial relationship between the location and the size of the 69 Grey Heron colonies existing in 1994 in refuge areas in eastern France after recolonisation following the decline of the species in the 19(th) century. We used five variables describing the hydrographical network, which are known to play a part in the location of the colonies in this area. The results showed that the distribution of the breeding colonies was not governed by the same elements of the hydrographical network. Three local strategies of spatial utilization were observed: the first one privileged the large but not dense rivers; the second, the dense network of small rivers; and the third, the ponds that were more restricted geographically. The spatial organization of the hydrographical elements is thus very important in the distribution and the size of the Grey Heron colonies.     

Habitat use by radio-tagged Namib Desert golden moles (Eremitalpa granti namibensis)

The Namib Desert golden mole (Eremitalpa granti namibensis) is morphologically, physiologically and behaviourally specialized for living in the harsh loose‐sand desert. Ecological studies have relied on visually tracking animals on the surface of sand dunes. A radio tag would allow individuals to be more reliably located, even while under the sand. We developed a radio attachment and gathered preliminary data on winter habitat use by six individuals during 21 days. We compare data from previous studies and suggest that the greater diurnal activity, smaller home ranges, and more restricted movement patterns that we found are related to the unusual thermal and metabolic biology of Eremitalpa.     

利用无线电遥测位点分析红腹锦鸡的生境利用

为了解红腹锦鸡(Chrysolophus pictus)的生境利用及其季节变化以及对距森林边缘不同距离的生境的利用情况，我们于1996年1月-8月、1998年11月-1999年9月分别在陕西佛坪和贵州宽阔水自然保护区，采用无线电遥测位点与随机点相比较的方法，从不同时空尺度定量分析了红腹锦鸡的生境利用。两研究区共遥测24只红腹锦鸡个体(亚成体和成体，6♂，15♀，3亚♂)，其遥测位点分布与随机点比较，冬、春和夏季3季节中均有极显著差异，落入各区域的活动位点与其期望位点数之间也存在着极显著差异。这说明红腹锦鸡对生境的利用不是随机的，而是有选择地利用。红腹锦鸡对距森林边缘不同距离的生境的利用有选择性，并存在着明显的季节变化。分析结果表明，红腹锦鸡在冬、春季对森林边缘和林缘开阔区的利用较多，有一定偏好。红腹锦鸡在两研究区的生境利用模式相似，但在对森林边缘和林缘开阔区的利用强度上，宽阔水研究区显著大于佛坪研究区[动物学报49(2)：179一184，2003]。