Use Of Forest Habitats Research Articles

Water-Level Fluctuations and Ungulate Community Dynamics in Central Uganda

Climate change has altered precipitation regimes with concomitant influences in hydrology. For a complex assemblage of ungulates, these water-level fluctuations might alter habitat partitioning thought to be crucial for coexistence in response to livestock introduction. We placed camera traps in three habitat types along the Mayanja River in central Uganda to evaluate space use by native and domestic ungulates. For each species, we assessed the difference in the proportion of days with camera-trap detections during three water-level conditions (low in 2017, normal in 2015, and high in 2016). Sitatunga was the only species regularly using wetlands; their use of remote wetlands remained consistent regardless of water-level conditions, and their use of forest habitats decreased during the study. In the forest, warthogs showed no change in use, while proportion of days with detections increased over time for all other ungulates. Our results indicate that ungulate community space use appears to be independent of hydrologic condition, and that risk for competitive exclusion between native and domestic ungulates is tempered by dietary and habitat use differences. Adaptations to dynamic hydrology appears to buffer consequences for ungulate communities; more serious are habitat losses to agriculture and development.

Can retention harvests help conserve wildlife? Evidence for vertebrates in the boreal forest

AbstractRetention harvesting, or the approach of leaving live mature trees behind during forest harvest, is used in natural disturbance‐based management to mitigate the effects of logging on biodiversity. However, responses of many boreal vertebrates to variable retention harvesting are unknown. We investigated the influence of different retention levels in forest harvests on stand use by wildlife 15–18 yr post‐harvest using a combination of surveys of wildlife signs (scats, middens) and camera trapping. Site‐level measures of forest structure, including canopy cover, horizontal cover, tree height, tree diameter, basal area, cover of downed coarse woody material, and understory plant cover, were used to describe post‐harvest differences in habitats used by common wildlife species in northwest Alberta's boreal forest. Stand use of six species (black bear, coyote, fisher, red squirrel, wolverine, woodland caribou) increased with level of retention, while stand use of two species (grouse, snowshoe hare) declined with retention level. Retention level did not significantly affect stand use of five species (American marten, Canada lynx, deer, gray wolf, moose). Higher levels of retention characterized by greater canopy cover, basal area, and abundance of deadwood were associated with use of forest habitats by late‐seral species. Woodland caribou, a species of conservation concern, was detected only in harvested stands with at least 20% retention. Greater understory and horizontal cover characterized lower levels of retention being attractive for early‐seral species. These findings demonstrate the value of retention harvesting for conservation of wildlife species in boreal forest, while highlighting the challenge of managing forests for multiple species with different habitat preferences.

Migration patterns and seasonal forest use by birds in the Brazilian Pantanal

SummaryThe use of forest habitats and migratory patterns are still unclear for tropical birds. Some are described herein for the Pantanal wetlands of Brazil. Thus, our aim was to describe different patterns of forest habitat use by birds and classify the birds’ migration patterns for the northern Pantanal region, Brazil. From September 1999 to December 2003, we sampled four forest types, during which we collected standardised data with mist-net captures and point counts, with additionalad lib.observations. We recorded 214 bird species: 113 (52.8%) were total habitat generalists; 41 (19.2%) were forest generalists; 19 (8.9%) were flooded habitat specialists; and 28 (13.1%) were not classified due to the low number of records; three other categories of habitat use divide the remaining 6% of records. About half of the species showed some migratory behaviour, these were classified by us according to the season they spent in the area: 121 species (56.5%) asresidents, 28 (13.1%) asrun-off and dry migrants, 11 (5.1%) asrun-off(winter)migrants, eight (3.7%) asdry(breeding)migrants, eight (3.7%) asdry and flooding(summer)migrants, eight (3.7%) asflooding migrants, three (1.4%) asflooding and run-off migrants, and 27 (12.6%) asuncommon. We constructed community occupancy models with six of the eight patterns of migration described; flooding migrants and run-off migrants were not modelled since the few species recorded also had very few detections. As expected, the model confirmed that species from all six tested migration patterns arrive and depart from the Pantanal across the seasons. Contrary to most Neotropical forests, there was a high percentage (43.5%) of non-resident species. The results show the need of investing heavily in preserving different landscape units within the Pantanal, but also in the surrounding Cerrado region, in order to conserve resident and short distance intra-tropical migrants.

Health Assessment of Free-Ranging and Captive Matschie's Tree Kangaroos (Dendrolagus matschiei) in Papua New Guinea

Medical evaluations were performed on free-ranging and captive Matschie's tree kangaroos (Dendrolagus matschiei) in Papua New Guinea. The health assessment included physical examination, morphometrics, cloacal swab; and blood, hair, and feces collection. Radio-collars were placed on free-ranging tree kangaroos to determine home range and forest habitat use. The free-ranging tree kangaroos were lightly anesthetized with tiletamine/zolazepam for the data collection. A total of nine free-ranging and seven captive tree kangaroos were evaluated; medical samples were collected from six and five animals, respectively. Results of physical examination, anesthetic monitoring, serum vitamin, mineral, trace nutrient, and electrolytes, whole blood heavy metal analysis, mycobacterial screening, and fecal examinations are presented. Free-ranging tree kangaroos had significantly lower values for beta carotene, copper, selenium, molybdenum, lead, and arsenic and significantly higher values for vitamin E than captive individuals. Cloacal swabs were all negative for Mycobacterium avium via polymerase chain reaction. Some free-ranging and captive individuals had positive coprologic exams revealing Eimeria spp. oocysts and strongyle spp. type ova. These are the first medical and anesthetic data published on Matschie's tree kangaroos from Papua New Guinea.

Comparative use of forest habitats by roe deer and moose in a human‐modified landscape in southeastern Norway during winter

AbstractThe negative impact of anthropogenic disturbance and land‐use changes on large mammals is generally recognized within conservation biology. In southeastern Norway, both moose (Alces alces) and roe deer (Capreolus capreolus) occur throughout human‐modified landscapes, facilitating an interesting comparative study of their habitat use. By using pellet group counts, we looked at the importance of forest structure, vegetation characteristics and human disturbance (e.g., distance to the nearest house, nearest paved road, and nearest edge between field and forest) in shaping the winter distribution of both species at multiple spatial scales, in non‐agricultural habitats. Moose occurred more often in areas with higher densities of heather and Vaccinium sp. in the ground layer, and used areas with more open forest structure. The proportion of built‐up areas, within a 1,000‐m buffer, negatively influenced moose occurrence. Roe deer occurred more often in areas with deciduous trees and patches with juniper and Vaccinium sp. in the ground layer, used areas near roads less, but were significantly associated with areas near the field–forest ecotone. The proportion of built‐up areas positively influenced roe deer distribution within a 2,500‐m buffer. Roe deer seem to be able to persist in more human‐dominated landscapes, possibly due to the availability of field–forest edges providing both high‐quality fodder and cover in close proximity. Moose, on the contrary, did not show any preference for areas associated with human disturbance, and their distribution was only associated with patches providing food.

The recent expansion of the brown hare (Lepus europaeus) in Sweden with possible implications to the mountain hare (L. timidus)

The brown hare (Lepus europaeus) expanded its Swedish distribution since the 1980s northwards and locally to new areas within its former range. Of 115 brown hare populations within the former range reported in a hunter enquiry, those established after 1980 were situated higher above the sea level than older ones and higher than neighbouring (<50 km) older populations. Reports on increased use of forest habitats by brown hares were equally frequent among recent and older populations, suggesting a process promoted solely by less harsh winters. Supposed hare hybrids were more often reported from hunting grounds with recent brown hare establishment, i.e. where the species expands in time and in space. In a 27-year dataset on brown hare observations, the recent increased use of forest habitats was supported in that maximum distances to agricultural land for brown hare sightings were higher in mild winters, whereas the proportions of the annual observations made during winter were lower. In 40-year bag records from two Swedish counties, the dynamics of the mountain hare (Lepus timidus) responded positively to snow parameters, whereas brown hares responded negatively. We suggest that the state of mountain hare populations primarily depends on winter conditions and predation pressure, whereas possible effects of hybridization are unclear. If winter conditions remain as in the last 15 years, mountain hare numbers are not likely to increase in southern Sweden, whereas the brown hare may expand even further. In either case, hybrids will occur in sympatric areas in frequencies probably related to the density of the respective true species.

The impact of recent logging and pond isolation on pond colonization by the frog Crinia signifera

A colonization experiment was used to investigate landscape use of a commercially managed wet forest in southern Tasmania by the ground-dwelling frog, Crinia signifera. Replicated artificial ponds were placed at increasing distances (20, 100, 250 and 500 m) from nine permanent breeding sites to investigate the effect of pond isolation on colonization. Four of these permanent breeding sites were surrounded by coupes that had been logged within the previous five years and five permanent breeding sites were surrounded by unlogged forest to investigate the effect of recent logging on colonization. The rate of colonization, the frequency of colonization, male size and female size (inferred from clutch size) were monitored over two breeding seasons. No pond isolation effects were found, indicating that G. signifera is randomly distributed throughout the forest landscape for up to 500 m around each permanent breeding site. Such patterns of forest habitat use indicate that management prescriptions should not only take into account the habitat characteristics of breeding sites but should also consider the surrounding terrestrial landscape. Ponds surrounded by unlogged forest were colonized almost two times faster than ponds surrounded by logged forest indicatlng that landscape modtfication can significantly alter amphibian mobility. These findings have consequences for total reproductive output especially in landscapes where breeding sites are highly variable and for species that are slow to colonize new breeding sites.

Response of Elk to Installation of Oil Wells

Environmental disturbance can affect use of home range by large, free-ranging ungulates, but quantitative assessments of such effects are rare. We compared seasonal and annual use of range and habitat in the population of elk ( Cervus elaphus ) at Line Creek in southcentral Mortana, 1988–1991, before, during, and after installation of an oil well. Use of range by elk during the post-drilling period in autumn was different from use during drilling and pre-drilling periods, but use of range also changed during the same periods in another local population of elk not subjected to disturbance from oil drilling. Use of range grid cells containing or adjacent to the well site declined during the post-drilling period, but seasonal and annual sizes in range and boundaries for the population were similar in all periods. Distances between individually marked elk did not differ across periods, suggesting that drilling did not affect the social stability of elk. Use of forest habitats in autumn increased after initiation of drilling. Results suggested that elk compensated for site-specific environmental disturbance by shifts in use of range, centers of activity, and use of habitat rather than abandonment of range.