Ground-dwelling Small Mammals Research Articles

Ectoparasitic mites, ticks (Acari: Trombidiformes, Mesostigmata, Ixodida) and insects (Insecta: Psocodea, Siphonaptera) of ground-dwelling small mammals in the Baltic States. An annotated checklist.

This paper presents an annotated checklist of 77 species of ectoparasitic mites, ticks (Acari: Trombidiformes, Mesostigmata, Ixodida) and insects (Insecta: Psocodea, Siphonaptera) found on ground-dwelling small mammals in the Baltic States (Estonia, Latvia, Lithuania). Eight species of five genera of chigger mites (Trombidiformes: Trombiculidae), 26 species of eight genera of laelapid mites (Mesostigmata: Laelapidae), six species of two genera of ixodid ticks (Ixodida: Ixodidae), 11 species of three genera of blood-sucking lice (Psocodea: Hoplopleuridae, Pediculidae, Polyplacidae) and 26 species of 15 genera of fleas (Siphonaptera: Ceratophyllidae, Ctenophthalmidae, Hystrichopsyllidae, Pulicidae) were recorded on ground-dwelling small mammals in the Baltic States. Neotrombicula japonica (Tanaka, Kaiwa, Teramura & Kagaya), Neotrombicula vulgaris (Schluger), Miyatrombicula muris (Oudemans), Hoplopleura edentula Fahrenholz and Polyplax hannswrangeli Eichler are recorded for the first time in the Baltic States.

Breeding behaviour of a pair of Spotted Harriers Circus assimilis near Tamworth, New South Wales

A pair of breeding Spotted Harriers Circus assimilis was observed in an agricultural environment near Tamworth, New South Wales, in winter–spring 2020 for 290 hours over 68 days from pre-laying and incubation to the post-fledging period. Laying occurred at the end of June, hatching at the beginning of August and fledging in mid September. Only the female incubated and brooded, and the male supplied all prey from the incubation period to late in Week 3 of the nestling period, after which the female contributed. Two chicks fledged of three that hatched; there was some sibling competition for food. The incubation period lasted 34 ± 1 days, and the nestling period 43 days for the older (female) chick and c. 40 days for the younger (male) chick. Prey consisted of ground-dwelling small mammals, birds and reptiles that are typical of agricultural land. The male’s prey-delivery rate to the incubating female was 0.22 item/h. Overall, the male delivered 0.31 item/h and the female 0.09 item/h to the nestlings, for a combined average of 0.4 item/h, peaking in the pre-fledging fortnight. The combined rate in the post-fledging period was 0.39 item/h (Week 1), declining to 0.16 item/h to the fledglings in Week 2 when only the male delivered prey and the adult female consumed some of his catch. Estimated biomass delivered ranged between ~20 and ~100 g/item (often 20–50 g/item). Breeding behaviour and nestling/fledgling growth and development are described. The juveniles appeared to be dependent or partly so for at least 3 weeks, and apparently roosted in the nest area in Week 4, after which they could not be located.

Urban size effect on biodiversity: The need for a conceptual framework for the implementation of urban policy for small cities

Answers are still being sought to the question of how to plan cities to ensure good living conditions for humans while also protecting urban biodiversity. We asked what is the minimum city size that causes the depletion of wildlife biodiversity, and how quickly does this process develop? We summarized data for wild ground-dwelling small mammals (Rodentia and Soricomorpha) living in green areas in cities/settlements of sizes from 1.3 thousand to 1.7 million inhabitants (Poland, Central Europe) and used various statistical tools to explore this issue. Our models indicate that the explicit transformation and depletion of ground-dwelling fauna occurs in cities with a density higher than 1000 people/km2 (20,000 inhabitants, area of 20 km2). We estimated species richness and the rate of diversity decline as a city grows. Our findings indicate that in order to preserve the relatively high biodiversity of native wildlife in cities (even in central areas) appropriate actions should be taken in the early stages of city development. This knowledge may facilitate the design of more sustainable cities and could be particularly useful for the promotion of the implementation of appropriate urban policies for smaller cities. Nowadays, the theory of sustainable design of small cities is still insufficient.

How small cities affect the biodiversity of ground-dwelling mammals and the relevance of this knowledge in planning urban land expansion in terms of urban wildlife

Fundamental principles regarding urban biodiversity are based on studies conducted in large cities. However we cannot know whether the same phenomena occur in smaller cities or how small cities affect biodiversity. Small cities are an inherent element of urbanization and in the future, most global urban growth is expected to take place in small and medium-sized cities. Understanding the effects of small cities on biodiversity will be an important aspect in planning urban land expansion. Our study examined the effects of a small city on communities of small ground-dwelling mammals on 41 sites arranged in a four step gradient of urbanization. In 6700 trap-days, we caught 2333 individuals comprising 15 species. In the downtown area the same phenomena as those described for large cities were observed: a reduction in species richness and diversity, a decline in the abundance of urban sensitive species and an increase in synurbic species. However, in contrast to large city studies, green areas outside the downtown area did not differ from rural sites in small mammal population parameters. This phenomenon of relatively unchanged fauna outside the downtown area shows that small cities have the potential to maintain a high level of diversity of small ground-dwelling mammals if appropriate planning of further building expansion is implemented. More studies of small cities are needed to better assess their impact on biodiversity. This knowledge can then be applied in better planning for urban wildlife. Generalizations based solely on large city studies are inadequate and may lead to incomplete or inappropriate conservation strategies for small cities.

Dispersal of bryophytes and ferns is facilitated by small mammals in the boreal forest

ABSTRACTBryophytes and pteridophytes are important contributors to ecosystem services in boreal regions. Abiotic agents are considered their main dispersers, but recent studies suggest that biotic agents including invertebrates, birds and large mammals might also be efficient dispersal agents. Dispersal of cryptogams by ground-dwelling small mammals is often assumed to occur, but has yet to be demonstrated. In this study, we present the first evidence of boreal cryptogam species being dispersed by ground-dwelling small mammals. In 2013 and 2014, we recorded bryophyte cover and fern presence in 35 sites in black spruce forest. We also collected diaspores by brushing the fur of 99 ground-dwelling small mammals live-trapped in the same sites. Diaspores were then germinated on nutrient agar for six months. Viable diaspores of five bryophyte species and one fern species were successfully grown. No association was found between the cryptogam community sampled on site and the diaspore community grown on artificial substrate. Unlike abiotic agents that randomly disperse cryptogams, small mammals are more likely to transport diaspores to suitable substrates where microhabitat requirements for germination are met. Our results highlight the need to consider a broad spectrum of dispersal agents when focusing on the community dynamics of cryptogams.

The transfer of 137Cs, Pu isotopes and 90Sr to bird, bat and ground-dwelling small mammal species within the Chernobyl exclusion zone

Protected species are the focus of many radiological environmental assessments. However, the lack of radioecological data for many protected species presents a significant international challenge. Furthermore, there are legislative restrictions on destructive sampling of protected species to obtain such data. Where data are not available, extrapolations are often made from ‘similar’ species but there has been little attempt to validate this approach.In this paper we present what, to our knowledge, is the first study purposefully designed to test the hypothesis that radioecological data for unprotected species can be used to estimate conservative radioecolgical parameters for protected species; conservatism being necessary to ensure that there is no significant impact.The study was conducted in the Chernobyl Exclusion Zone. Consequently, we are able to present data for Pu isotopes in terrestrial wildlife. There has been limited research on Pu transfer to terrestrial wildlife which contrasts with the need to assess radiation exposure of wildlife to Pu isotopes around many nuclear facilities internationally.Our results provide overall support for the hypothesis that data for unprotected species can be used to adequately assess the impacts for ionising radiation on protected species. This is demonstrated for a range of mammalian and avian species. However, we identify one case, the shrew, for which data from other ground-dwelling small mammals would not lead to an appropriately conservative assessment of radiation impact. This indicates the need to further test our hypothesis across a range of species and ecosystems, and/or ensure adequate conservatism within assessments.The data presented are of value to those trying to more accurately estimate the radiation dose to wildlife in the Chernobyl Exclusion Zone, helping to reduce the considerable uncertainty in studies reporting dose-effect relationships for wildlife.A video abstract for this paper is available from: http://bit.ly/1JesKPc.

Logging residues conserve small mammalian diversity in a Malaysian production forest

The extraction of large trees by selective logging in tropical production forests often results in a reduction of natural fallen trees for a long period after logging has been completed. This causes a population decrease for various small mammals that exploit fallen trees to live. We expect that logging residues, which are unmerchantable upper parts of logged trees, will alleviate the negative effects of the reduced volume of naturally fallen trees immediately after logging. To examine this issue, we compared the activity of small mammals in forest floor habitats with and without logging residues in a Malaysian production forest using a camera trapping technique. We tested the hypothesis that the activity of small mammals would be higher on forest floors with logging residues when compared with those without them; our study affirmatively supported this hypothesis. Therefore, logging residues are expected to have positive roles in maintaining small mammal diversity at the ground level in production forests. Recently commercial use of logging residues has been promoted; however, removing all logging residues from a production forest would severely and negatively affect the diversity of ground-dwelling small mammals. In addition, for small mammals which essentially require fallen trees to survive, populations will shrink or in a worst case scenario, they would become extirpated from production forests if all logging debris is removed.

Influence of Human Disturbance to the Small Mammal Communities in the Forests

Small mammals have been proposed playing an important role in the energy flow and regeneration of forest ecosystems. We compared species richness, diversity (H’) of small mammal communities and abundance of six dominant species of small mammals in disturbed and protected forests (four age classes: 6 - 10, 11 - 15, 16 - 20 and 31 - 40 years old) in China. We also investigated the structural variables (such as species richness, cover rate and abundance of shrubs and grasses) in the bottom layer, which considered to be important for small mammals and might be altered by human disturbance. The relationships between small mammals and these structural variables were examined to determine the potential effects of human disturbance on the small mammals in the restored forests. Our results indicated that the structure and composition of the vegetation in the bottom layer were simplified by human disturbance, while the abundance and cover rate of grasses were significantly increased. Although no significant differences were observed in species richness of small mammals between the protected and disturbed forests at the same age, the diversity index of small mammals in the protected forests was always significantly higher than in the disturbed forests. Regression showed that the species richness and diversity of small mammals increased with the species richness of shrubs, and was negatively correlated to the cover rate of grasses in the bottom layer. Human disturbance increased the total abundance of small mammals, and the increased cover rate of grasses in the bottom layer was beneficial to the abundance of small mammals. Obvious succession of small mammal communities occurred as the protected forest aged. In the protected forests, small ground-dwelling mammals (A. chevrieri, E. miletus and M. pahari) were the dominant species in the younger forests. Other mammals (T. belangeri, D. pernyi and C. erythraeus) gradually became the dominant species as the protected forests aged. However, in the disturbed forests, the smaller ground-dwelling mammals (T. belangeri, D. pernyi and C. erythraeus) were always the dominant species at all ages of the disturbed forests. Regression indicated that the cover rate of grasses in the bottom layer was beneficial to the three smaller body size and ground-dwelling small mammal species, while the shrubs were beneficial to the three bigger body size mammal species.

A preliminary study of the biodiversity of ground-dwelling small mammals in Badagongshan National Nature Reserve, Hunan Province

Little is known about the diversity patterns of mammals in the Badagongshan National Nature Reserve, Hunan Province, although the reserve was established in 1982. During September and October of 2012, the diversity of ground-dwelling small mammals was investigated using live traps, pitfalls and camera traps in a permanent forest dynamics plot and other nearby vegetation types. We captured 12 species of ground-dwelling small mammals, including eight species of Rodentia and four species of Insectivora. Pres- ently, there are 20 species of ground-dwelling small mammals recorded in the Badagongshan National Nature Reserve, including six new species recorded in this study, i.e., Eothenomys melanogaster, Typhlomys ciner- eus, Apodemus draco, Anourosorex squamipes, Blarinella griselda, and Sorex thibetanus. The body mass of the individuals captured by live traps was much larger than that of the individuals captured by pitfall traps. Our study also indicates that the diversity patterns of ground-dwelling small mammals are affected by the habitat types. Therefore, we recommend that a combination of different methods be used to effectively monitor mammal diversity in the Badagongshan National Nature Reserve.

Do northern spotted owls use harvested areas?

The 2011 Revised Recovery Plan for the northern spotted owl (Strix occidentalis caurina) declared that active forest management is compatible and consistent with recovery goals. The plan indicated that ecologically motivated silvicultural treatments should improve stand conditions, promote forest resiliency, and develop late-successional structural complexity over the long term. Yet most biologists believe that intensive, even-aged silvicultural systems (i.e., clearcut, seed-tree, or shelterwood regeneration methods) degrade habitat for northern spotted owls. Only for the coastal redwood forests of California is it broadly accepted that small-patch clearcut harvest units interspersed within a landscape containing significant large stands of large, old trees can provide adequate habitat. Spotted owls prey upon ground-dwelling prey, such as dusky-footed woodrats (Neotoma fuscipes), in these situations, primarily along edges of 6–30year old clearcuts that contain dense patches of shrubs and hardwoods as well as woody debris. Demographic pressures presumably cause surplus prey to emigrate into adjacent older stands with sparse understories, where they may be more vulnerable to predation by spotted owls. During 5 radio-telemetry studies in both the Klamath and Coastal Redwood Physiographic Provinces, we detected and observed northern spotted owls foraging as far as 600m from forests within harvest-created hardwood/shrub patches that contained scattered conifers and snags. Preferential use of such areas occurred in winter, especially in patches with conifer basal area of 9–18m2/ha that were outside of dense nesting areas. In areas where ground-dwelling small mammals comprise a significant proportion of the owl’s prey base, we hypothesize that use of young harvest units with retained conifers may contribute to spotted owl conservation. Such treatments may promote greater prey biomass, which could assist females to attain a high plane of nutrition prior to nesting. This hypothesis should be tested and refined via adaptive management experiments.

The reptile, bird and small mammal fauna of Dune Mallee Woodlands in south-western New South Wales

Baseline surveys of reptiles, birds and small mammals that occur in Dune Mallee woodlands in the Lower Murray Darling catchment of south-western New South Wales were conducted at 60 sites between October 2007 and March 2008. These surveys comprise the first round of a catchmentwide monitoring programme to obtain a measure of the distribution and abundance of 21 priority threatened fauna species that inhabit Dune Mallee Woodlands. A total of 127 fauna species were recorded, which included 19 of the possible 21 threatened fauna species. The 127 species comprised 37 reptile species, 15 bat species, three small mammal species and 72 bird species. The mean species richness recorded at each three hectare survey site for birds was 14.7, reptiles 7.1, small ground dwelling mammals 0.5 and bats 3.0. Mean abundance for birds was 42.7, reptiles 13.1, small ground dwelling mammals 1.0 and microbats 3.7. These surveys represent the most comprehensive inventory of fauna of the Dune Mallee Woodlands of the Lower Murray ...

The importance of incorporating imperfect detection in biodiversity assessments: a case study of small mammals in an Australian region

AbstractAim Assessments of biodiversity are an essential requirement of conservation management planning. Species distributional modelling is a popular approach to quantifying biodiversity whereby occurrence data are related to environmental covariates. An important confounding factor that is often overlooked in the development of such models is uncertainty due to imperfect detection. Here, I demonstrate how an analytical approach that accounts for the bias due to imperfect detection can be applied retrospectively to an existing biodiversity survey data set to produce more realistic estimates of species distributions and unbiased covariate relationships.Location Pilbara biogeographic region, Australia.Methods As a component of the Pilbara survey, presence/absence (i.e. undetected) data on small ground‐dwelling mammals were collected. I applied a multiseason occupancy modelling approach to six of the most common species encountered during this survey. Detection and occupancy rates, as well as extinction and colonization probabilities, were determined, and the influence of covariates on these parameters was examined using the multi‐model inference approach.Results Detection probabilities for all six species were considerably lower than 1.0 and varied across time and species. Naïve estimates of occupancy underestimated occupancy rates corrected for species detectability by up to 45%. Seasonal variation in occupancy status was attributed to changes in detection for two of the focal species, while reproductive events explained variation in occupancy in three others. Covariates describing the substrate strongly influenced site occupancy for most of the species modelled. A comparison of the occupancy model with a generalized linear model, assuming perfect detection, showed that the effects of the covariates were underestimated in the latter model.Main conclusions The application of the multiseason occupancy modelling approach to the Pilbara mammal data set demonstrated a powerful framework for examining changes in site occupancy, as well as local colonization and extinction rates of species which are not confounded by variable species detection rates.

Initial response of small ground-dwelling mammals to forest alternative buffers along headwater streams in the Washington Coast Range, USA

We assessed the short-term effects of alternative designs of forested buffer treatments along headwater streams on small ground-dwelling mammals in managed forests in western Washington, USA. Over three summers (one pretreatment and two posttreatment), we trapped 19 mammalian species along 23 streams in the northern Coast Range. We compared faunal communities in unlogged controls with riparian treatments: (1) clearcuts (no buffer) to the stream bank, (2) clearcuts with continuous buffer strips from a few to 20m each stream side, and (3) clearcuts with small patch (<0.6ha) buffers left to protect sensitive streamside terrain. We estimated abundance (Nˆ) of eight common and three less common species with simple models and capture indices, respectively, and analyzed effects of treatments and community measures on relative abundance compared to controls and over time. Habitat and forest stand changes after treatments included reduced live standing trees and canopy, more dead down wood, and increased ground plant species richness, evenness, and diversity, particularly in the patch and no buffers. The forest obligate Peromyscus keeni significantly declined in all treatments. No other species declined in strip buffers. Species with statistically greater Nˆ in treatments included the early-seral microtine Microtus oregoni, the semi-arboreal generalist Tamias townsendii and the old forest specialist Myodes gapperi in all treatments; the generalist Peromyscus maniculatus in strip and no buffers; and the early-seral riparian Zapus trinotatus in patch buffers. Postlogging trends in Nˆ were negative for two common shrews, Sorex monticolus and Sorex trowbridgii. Moist soil denizen Neurotrichus gibbsii capture rates were significantly lower in clearcut no buffers. Captures were low for two species of semi-aquatic shrews, Sorex bendirii and Sorex palustris, but in general, S. palustris responded poorly to treatments. Windfall was an important proximate influence on buffer function because persistence was low and created structural diversity in dynamic change. The alternative buffers were ineffective in retaining the habitat and relative abundance of individual small mammal species. Species composition similarity also significantly declined in the clearcuts. Change in species richness, evenness, diversity and total mammals captured in treatments however were not different. Control streams maintained faunal biodiversity but abundance of about half of the species changed following treatment. Steep topography, weather events, and small buffer size advanced habitat changes that influenced small mammal response to treatments. Site-specific data are necessary in logging unit planning along headwater streams, if the management goal is the maintenance of communities observed in undisturbed forest.

Effects of non-native spruce plantations on small mammal communities in subarctic birch forests

Voles and shrews are key species in northern forest ecosystems. Thus, it is important to quantify to what extent new forestry practices such as planting of non-native tree species impact these small mammals. In northern Norway stands of coastal subarctic birch forests have increasingly been converted to non-native spruce stands during the last century. This leads to changes in the forest floor vegetation and soil conditions that can be expected to negatively impact the community of ground-dwelling small mammals. In this 10-year trapping study we contrasted seasonal small mammal population abundances in spruce plantations with four birch forest varieties. Six different small mammal species were trapped (in descending order of abundance; common shrew Sorex araneus, red vole Myodes rutilus, field vole Microtus agrestis, grey-sided vole M. rufocanus, pygmy shrew S. minutus and water shrew Neomys fodiens). None of the voles appeared to exhibit temporal dynamics resembling population cycles. The three most numerous species were clearly less abundant in the spruce plantations compared to the other forest types. Autumn abundances were most impacted by spruce plantations, indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats (i.e. field vole and common shrew) were most impacted by tree species conversion. Still young spruce plantations inter-mixed with birch trees and the ecotone habitat, sustained small mammal abundances comparable to the native birch forests. This implies that managing spruce plantations to maintain a mix of different tree species and high spatial heterogeneity (i.e. more ecotones), will reduce the negative impacts on the small mammal community. On the contrary, if young spruce plantations, as they age become spruce monocultures covering larger parts of the landscapes than they do presently, the negative effects on small mammal communities may be larger than observed in the present study.

Small mammal populations in a eucalypt forest affected by fire and drought. I. Long-term patterns in an era of climate change

This paper reports a study of ground-dwelling, small mammals in coastal eucalypt forest in south-eastern Australia from 1970 through 2005. During this time, the study area burnt in an intense fire in December 1972 and was partially burnt in November 1980. Both fires were associated with prolonged drought. The mammals studied comprised two dasyurid marsupials, Antechinus agilis and A. swainsonii, two native murid rodents, Rattus fuscipes and R. lutreolus, and the introduced house mouse Mus musculus. After intensive sampling throughout the year from 1970 through 1972 to establish basic ecological and population parameters of the small mammal community, populations were sampled annually during late autumn and early winter before the onset of breeding. There were marked differences in the annual (autumn/winter) abundances of all species; numbers of A. agilis ranged from 4 to 142 individuals; A. swainsonii 0 to 43; R. fuscipes 4 to 54; R. lutreolus 0 to 11; M. musculus 0 to 23. Following the 1972 fire, numbers fell to the lowest level recorded during the study and each population subsequently disappeared from the plot between the 1973 and 1974 winter censuses. The less intense 1980 fire did not lead to extirpation, but numbers of A. agilis, A. swainsonii and R. fuscipes declined as drought conditions persisted through 1983. R. lutreolus occurred consistently only following the fires, when a grassy ground vegetation favoured by this species developed. Similarly, M. musculus colonised within two years of the fires and persisted on the plot for 3–4 years before disappearing. Following the fires, populations of the omnivorous R. fuscipes recovered first followed by the scansorial, insectivorous A. agilis and last by the fossorial, insectivorous A. swainsonii. Two primary conclusions emerged from this study. First, the intense fire of 1972 did not kill all the animals immediately, but led to the disappearance of each species from the plot over 18 months. Thus, intense fire had a delayed but catastrophic impact on small ground-dwelling mammals. The fluctuations in population levels, covering more than an order of magnitude, demonstrate that factors other than fire, such as rainfall and drought, drive the population dynamics of these small mammals. As stability and recovery are not features of local populations, long-term studies of benchmark populations are necessary to manage forest biodiversity.

Environmental associations of small ground-dwelling mammals in the Pilbara region, Western Australia

Environmental associations of small ground-dwelling mammals in the Pilbara region, Western Australia

Factors Influencing the Occurrence of Small Ground-Dwelling Mammals in Southeastern Mainland Australia

We investigated the occurrence of small, ground-dwelling mammals (marsupial mice and rodents) across 128 forested study sites representing a stratified sample of the climatic, geological, and topographic features of far southeastern mainland Australia. We then developed statistical models for the occurrence of the agile antechinus (Antechinus agilis), dusky antechinus (A. swainsonii), and bush rat (Rattus fuscipes) based on various environmental attributes measured for each site. At a landscape scale, the climatic factor mean minimum temperature of the coldest month was an important explanatory variable for the bush rat, with the likelihood of its occurrence increasing with increasing temperature during that period. Sites with greater precipitation during the driest quarter of the year were more likely to support bush rats and the agile antechinus. At an on-site scale, protected slopes and gullies were more likely to support bush rats, and the occurrence of bush rats and the dusky antechinus increased at sites with a higher number of large fallen trees. In multiple-use forests, increasing the number of large fallen trees after timber harvesting may increase habitat quality for both the dusky antechinus and the bush rat, and retaining habitat on protected slopes and gullies also may be important for the latter species.

Prediction of the distribution and abundance of small mammals in the eucalypt forests of south-eastern Australia from airborne videography

The relationship between forest structure or habitat complexity and distribution and abundance has been demonstrated for a variety of mammalian species in the southern forests of Australia. Recently, studies that utilise airborne videography data have predicted forest structure across forested landscapes. This paper unites these two fields of research. Existing models of species abundance were applied to spatial estimates of habitat complexity to produce predictions of the distribution and abundance of two small ground-dwelling mammals commonly found in eucalypt forests. The spatial estimates of habitat complexity were extrapolated across the landscape from videography at 2-m spatial resolution on four 1-km 2 study areas. To examine the accuracy of the abundance predictions, trapping grids for the two species were established across a range of abundances. Linear regression showed a strong positive relationship between the predicted distribution and abundance from the videography and the recorded distribution and abundance for the species.

Competition between Two Australian Rodent Species: A Regression Analysis

Empirical evidence and observations suggest that competition exists between two native rodents, Rattus lutreolus velutinus and Pseudomys higginsi , living in a wet sclerophyll forest, Tasmania, Australia. We used a standardized regression technique to assess competition between the two species and its temporal changes throughout the year. With our time-series data, we also tested the validity of our estimated competition coefficients by comparing regression residuals for a given species in one season to that in another. Overall, the two species competed asymmetrically for space with R. l. velutinus competitively dominant over P. higginsi . In winter (June-October), competition was low, and it reached a maximum during the breeding season (November-April). In the dispersal period (March-May), intensity of competition decreased, but was still higher than in winter, as subadults entered the trappable population. Estimated competition coefficients are validated by analyzing residuals from those three seasons. Results indicate that competitive ability in ground-dwelling small mammals is correlated positively with habitat specialization, but both may be related to body size. Intensity of competition also depends on the population phase of competing species. Our findings suggest that the standardized regression technique can be used reliably to uncover community patterns.

Effects of variable-intensity logging on mammals, reptiles and amphibians at Waratah Creek, southeastern New South Wales

Populations of arboreal marsupials, small ground-dwelling mammals, reptiles and amphibians were assessed in forest before and after logging. Different levels of canopy retention were specified to estimate the effect of varying intensities of logging on these fauna. The logging treatments imposed were; unlogged, and the retention of approximately 72%, 58% and 30% of the original canopy cover. This corresponded to 62%, 52% and 21 % retention of the original tree basal area on each logged area. The objectives of the study were to determine the sensitivity of species to logging, both in terms of the intensity of the initial impact and in terms of the time to recovery following disturbance, and to develop methods for managing areas within wood production forests where special wildlife values have been identified. A total of 53 species was recorded in the 500 ha study area, only 18 (34.0%) of which were abundant enough for assessments to be made about the effects of logging. The arboreal marsupials, in particular the Greater Glider Petauroides volans, were among the species more sensitive to logging disturbance. The small, ground-dwelling mammals and the reptiles that were sampled adequately in this study appeared to be relatively unaffected by logging or they recovered quickly (most within eight years, and probably all within 10?15 years) following logging. Despite a large survey effort, insufficient data were available to assess the effects of logging on most species of frogs, although two species may have been advantaged. The species requiring management consideration include those that declined as a result of logging, but which had not recovered within eight years (the Greater Glider, the Yellow-bellied Glider Petaurus australis, the Sugar Glider P. breviceps, and the skink Niveoscincus coventryi), the species that declined in both logged and unlogged areas (the frogs Pseudophryne bibronii, Limnodynastes peronii, Geocrinia victoriana and Heleioporus australiacus), and the species for which the data were too sparse to make any assessments. It is unclear when the species most disadvantaged by integrated logging, that is, the large gliding possums, will recolonize the logged areas. The persistence of these gliders was attributed to the retention of unlogged forest within and adjacent to logged areas. This highlights the role of riparian reserves ("wildlife corridors") and filter strips in retaining residual populations of the Greater Glider and the Yellow-bellied Glider until the logged areas are suitable for recolonization, and the importance of determining the effective size for these unlogged reserves. The data were not sufficient to determine conclusively whether reduced logging intensity at the levels applied was a better option than standard logging practices for managing populations of gliding possums in these forests. The results of this study, which was conducted in a forested landscape that was multi-aged but predominantly unlogged, may not be comparable to intensively-managed forests in which there is a lower proportion of unlogged forest and where multiple logging events have occurred.