bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimum viable metapopulation size of a beetle, Osmoderma eremita, living in tree hollows
Authors: Ranius Thomas
Published: February 2006

Osmoderma eremita, an endangered beetle restricted to hollow trees, was surveyed in stands of different size, isolation and physical characteristics in an area in south‐eastern Sweden. To infer habitat occupancy the presence/absence of fragments of adult body parts was used. Mark–release–recapture of adults with pitfall traps set in tree hollows was carried out to estimate local population size. Habitat occupancy/tree was higher in larger stands than in smaller stands, but there was no correlation between occupancy/stand and isolation of stands. This suggests dispersal is important in the population processes within stands, but not between stands. Osmoderma eremita was found in most of the larger stands and this probably mirrors the fact that the density of old‐growth oaks has been much higher in the area than today. Habitat fragmentation over the last two centuries has disrupted the network of habitat patches, thus preventing dispersal into smaller, younger stands. A minimum number of suitable trees aggregated in stands seems to be necessary to provide long‐term viability of local O. eremita populations. To preserve viable O. eremita populations, it is therefore necessary to increase size and connectivity of stands with hollow trees.
Incorporating land cover information into regional biodiversity assessments in South Africa
Authors: Wessels K. J. , Reyers B. , Van Jaarsveld A. S.
Published: February 2006

Anthropogenic natural habitat transformation presents the single most important threat to global biodiversity. Land cover data, based on Landsat Thematic Mapper (TM) imagery, were used to derive land use information for the Gauteng, Mpumalanga and Northern provinces of South Africa. The assessment integrated land use data with species presence data (15 × 15 minute grid cell resolution) for butterflies, mammals, birds and endemic vascular plants. The objectives of the present study were: (1) to identify areas at a regional scale where there is a possible conflict between biodiversity conservation interests and current land uses; (2) to investigate the influence of incorporating a land use constraint (LUC) into a conservation area selection algorithm, while taking cognizance of the existing reserve system; (3) to investigate the circumstances of species recorded within these conflict areas. Many grid cells identified as species richness hotspots, rarity hotspots or as part of the complementary network selected by the unconstrained algorithm were in reality largely transformed or modified. These areas should thus be avoided when striving to identify a viable conservation network. Although the LUC algorithm selected more grid cells to represent all species, it succeeded in increasing the percentage of natural vegetation within the selected conservation network and highlighted areas where potential conflicts should be thoroughly investigated at a local scale.
Implications of high intrinsic growth rate of a tortoise population for conservation
Authors: Hailey Adrian
Published: February 2006

Demographic analyses suggest that chelonians will have a low ability to withstand harvesting, although most have been based on stationary or declining populations. In contrast to this prediction, a population of Testudo graeca grew at the instantaneous rate r= 0.137 from 1980–1990, with a doubling time of 5 years. r was similar in both adult and 10 cm animals, showing that this high rate was not due to changes in population structure, and may thus be taken as an intrinsic rate of increase (rm). rm was higher than that of most large mammals, and suggests that sustainable harvesting would be a viable conservation strategy for chelonians if tightly regulated. Ranching or farming operations for chelonians would be even more likely to succeed, given their high fecundity. A resumption of trade in Mediterranean tortoises is, however, unlikely to be economically sustainable.
Biases associated with population estimation using molecular tagging
Authors: Waits Juliann L. , Leberg Paul L.
Published: February 2006

Although capture–recapture techniques are often used to estimate population size, these approaches are difficult to implement for a wide variety of species. Highly polymorphic microsatellite markers are useful in individual identification, and these ‘molecular tags’ can be collected without having to capture or trap the individual. However, several sources of error associated with molecular identification techniques, including failure to identify individuals with the same genotype for these markers as being different, and incorrect assignment of individual genotypes, could bias population estimates. Simulations of populations sampled for the purpose of estimating population size were used to assess the extent of these potential biases. Population estimates tended to be biased downward as the likelihood of individuals sharing the same genotype increased (as measured by the probability of identity (PI) of the multi‐locus genotype); this bias increased with population size. Populations of 1000 individuals were underestimated by ≥5% when the PI was as small as 1.4 × 10−7. A similar‐sized bias did not occur for populations of 50 individuals until the PI had increased to approximately 2.5 × 10−5. Errors in genotype assignment resulted in overestimates of population size; this problem increased with the number of samples and loci that were genotyped. Population estimates were often >200% the size of the simulated populations when the probability of making a genotyping error was 0.05/locus and 7–10 loci were used to identify individuals. This bias was substantially reduced by decreasing genotyping error rate to 0.005. If possible, only highly polymorphic loci that are critical for the identification of the individual should be used in molecular tagging, and considerable efforts should be made to minimize errors in genotype determination.
Metapopulation viability of the marsupial Micoureus demerarae in small Atlantic forest fragments in south‐eastern Brazil
Authors: Brito Daniel , Fernandez Fernando A. S.
Published: February 2006

A population viability analysis (PVA) was carried out for populations of the arboreal didelphid Micoureus demerarae in eight small (1.5–15.0 ha) forest fragments in south‐eastern Brazil. Analysis was based on field data obtained through demographic studies carried out since 1995. Populations are small, but connected by dispersing individuals, thus forming a metapopulation. Frequency of catastrophic fires was estimated from the Reserve's historical records. We used the computer package VORTEX for all analyses. All populations and the metapopulation were found to be endangered within 100 years (extinction probability > 0.98). A sensitivity analysis was run varying six parameters: three demographic (sex ratio, migration and mortality rates), two environmental (K, fire frequency) and one genetic (level of inbreeding depression). Genetics, K, mortality rates and sex ratio seemed to play major roles to population persistence, whereas catastrophes and migration rates had a secondary role. Among demographic factors, extinction rate was least sensitive to migration rate. Micoureus demerarae can be used as a model species, thus improving our knowledge of how extinction‐prone populations of neotropical arboreal marsupials in forest fragments might be, and which management actions could decrease such risks.
Improving translocation success: an experimental study of anti‐stress treatment and release method for wild rabbits
Authors: Letty Jérôme , Marchandeau Stéphane , Clobert Jean , Aubineau Jack
Published: February 2006

Translocation is an important tool in conservation biology. However, translocation success is generally low for numerous animal species, therefore experiments are required for improvement. We carried out an experimental translocation of European wild rabbits (Oryctolagus cuniculus). The results may be of great interest for conservation biology, although we used a common species. As rabbits are known to experience a high mortality during the first days following release, it was necessary to assess the influence of handling trauma and environment novelty, respectively, and ways of suppressing them. Both tranquillization treatment during handling and a ‘soft’ release protocol (acclimatization pens in the new territory) were tested. Tranquillization did not increase survival, while the effect of acclimatization depended on sex. Females survived better when acclimatized, while males showed the opposite tendency. This difference is discussed in terms of sex‐specific social behaviour, which is possibly an important correlate of translocation success. Finally, environmental stress seemed to override handling stress in determining the level of early survival for translocated wild rabbits.
Microsatellite analysis reveals that domestic cat (Felis catus) and southern African wild cat (F. lybica) are genetically distinct
Authors: Wiseman R. , O'Ryan C. , Harley E. H.
Published: February 2006

The amount of genetic differentiation between the African wild cat (Felis lybica) and the domestic cat (F. catus) in southern Africa is not known, but there is concern that interbreeding between the two may have been sufficiently extensive to threaten the status of the wild cat as a genetically distinct population. Eight hypervariable microsatellite loci were therefore used to determine the genetic relationships within and among wild and domestic cat populations. Measures of genetic differentiation, including FST and RST, confirmed significant differentiation between the wild and domestic cat populations and no significant differentiation between two widely separate domestic cat populations. Our data indicate that the level of genetic introgression is lower than previously thought. This enhances the conservation status of the African wild cat and demonstrates the need for the implementation of feral cat control in and around game reserves and rural areas.
Effects of forest fragmentation on the distribution of the lizard Psammodromus algirus
Authors: Díaz José A. , Carbonell Roberto , Virgós Emilio , Santos Tomás , Tellería José L.
Published: February 2006

This study reports the population responses of the lizard Psammodromus algirus to forest fragmentation by comparing its distribution in two contrasting situations of habitat conservation: a well connected mosaic landscape (forest patches larger than 2000 ha and/or connected by corridors that prevent their isolation), and an archipelago of forest remnants embedded within a matrix of cereal fields. The frequency of occurrence of P. algirus was larger in the unfragmented habitats (14 out of 19 censused plots) than in the fragments (two out of of 21 wood‐lots). Vegetation structure was a good predictor of lizard occurrence under conditions of no fragmentation, but not in the fragments, where high plant cover seemed a necessary, but insufficient, condition for the survival of lizard populations, and where remnant size was the only variable that differed significantly between wood‐lots with and without lizards. Historical fragmentation of the habitat is also crucial for understanding the current distribution of lizards, as shown by their absence from a large forest that was highly fragmented in the past but which has been regenerating for decades. It is hypothesized that the combined effects of fragmentation and predation in small remnants have led to the extinction of P. algirus in fragments smaller than c. 90 ha, recolonization being prevented by the very limited dispersal abilities of these forest lizards.
Microsatellite analysis of population structure and genetic variability in peregrine falcons (Falco peregrinus)
Authors: Nesje M. , Røed K. H. , Bell D. A. , Lindberg P. , Lifjeld J. T.
Published: February 2006

Genetic variability and population structure in the endangered peregrine falcon (Falco peregrinus) were studied using DNA microsatellite markers. Special emphasis was placed on the subspeciesF. p. peregrinusliving in Scandinavia and Scotland. For comparative purposes, three North American peregrine subspecies (F. p. tundrius,F. p. pealeiandF. p. anatum) and one Tasmanian subspecies (F. p. macropus) were included in this analysis. Twelve DNA microsatellite loci were analysed across a total of 146 individuals. The amount of genetic variation did not differ in peregrine populations for which adequate sample sizes were obtained. WithinF. p. peregrinus, significant genetic differentiation was found between populations in northern and southern Scandinavia and between the Scandinavian and Scottish populations, while the populations in south‐eastern Norway and south‐western Sweden did not differ significantly. Analysis of cliff‐nesting peregrines in northern Sweden and bog‐nesting peregrines in northern Finland/Sweden suggests that the difference in nesting habitat is not associated with genetic differentiation. Population structuring inF. p. peregrinusis further supported by an assignment test, wherein simulated genotypes are correctly assigned to the northern and southern Scandinavian and Scottish populations with relatively high probabilities, and by analysis of allele‐sharing among individuals. Cluster analysis of genetic distances grouped populations of peregrines in accordance with their subspecific designation, and peregrines on either side of the Atlantic Ocean were clearly separated.
Multipack dynamics and the Allee effect in the African wild dog, Lycaon pictus
Authors: Courchamp Franck , Clutton‐Brock Tim , Grenfell Bryan
Published: February 2006

The current decline of the highly endangered African wild dog (Lycaon pictus) may be partly due to the population dynamics induced by their social system. African wild dogs are obligate co‐operators, and their need for helpers could generate inverse density dependence at the pack level. We show, through a mathematical model, that this can create an Allee effect, leading to a lower population size and a higher risk of population extinction, compared to populations with direct density dependence. This is due to three different processes. All three processes can increase population extinction individually and probably occur simultaneously in African wild dogs. First, inverse density dependence causes significantly higher rates of pack extinction. Second, it also increases the probability of failure to colonize territories by founders. Third, the Allee effect at the pack level (with a critical number of individuals), generates an Allee effect at the population level (with a critical number of packs). These three processes are likely to apply to other obligate co‐operative breeders. Furthermore, our results suggest that habitat fragmentation and destruction, as well as increased human pressure, increase the effects of inverse density dependence. Direct and indirect anthropogenic effects may thus be more detrimental to obligate co‐operative breeders than to other species.
Cryptic local populations in a temperate rainforest bat Chalinolobus tuberculatus in New Zealand
Authors: O'Donnell Colin F. J.
Published: February 2006

Population structure of the threatened long‐tailed bat (Chalinolobus tuberculatus) was studied over five summers between 1993 and 1998, in temperate Nothofagus rainforest in Fiordland, New Zealand. Composition of 95 communal groups was sampled and spatial distribution of individually marked bats investigated. Individual C. tuberculatus moved to new roost sites virtually every day. Long term non‐random associations among individuals were found by a cluster analysis that revealed three distinct social groups. Groups contained on average 72.0 (± 26.0) (mean ± SD), 99.3 (± 19.0) and 131.7 (± 16.5) marked individuals/year. Collective foraging ranges of the three groups overlapped but roosting occurred in three geographically distinct adjacent areas. Only 1.6% of individuals switched between groups. Non‐reproductive females and males switched between groups more often than reproductive females but individuals switched only once or twice during the study and then just for one night. Juveniles of both sexes were associated with their natal group as 1 year‐olds and then later when breeding. Social groups were cryptic because foraging ranges of groups overlapped, bats belonging to each group spread over many roosts each day, and these roost sites changed from day to day. Bats moved infrequently between groups, potentially linking the local population assemblages. Future research should explore whether the population is structured in demes. Population structure did not conform to traditional metapopulation models because groups occurred in homogeneous habitat extending over a large geographical area. Conserving bat populations should entail preserving a representative number of subgroups but development of models for predicting minimum number of effective local populations is still required.
A preliminary assessment of the contribution of nature reserves to biodiversity conservation in Great Britain
Authors: Hopkinson Paul , Travis Justin M. J. , Prendergast John R. , Evans Julianne , Gregory Richard D. , Telfer Mark G. , Williams Paul H.
Published: February 2006

As a signatory of the Convention on Biological Diversity, the United Kingdom (UK) Government is obliged to conserve and enhance biodiversity. One step towards addressing this goal is to determine the level of biodiversity conservation already achieved within the current array of protected areas. We used national distribution data for ten taxonomic groups, and location information for three reserve networks, to assess the contribution of nature reserves to biodiversity conservation in Great Britain at the 10 km square (=100 km2) resolution. For several taxonomic groups, 10 km squares containing nature reserves had a significantly greater overlap than random networks with both hotspots (areas of high species richness) and complementary areas (sets of sites within which all species are represented). In addition, more than 94% of species from each taxonomic group have been recorded within the 10 km squares of the three reserve networks. These results provide some encouragement in terms of the UK meeting its commitment to conserve biodiversity.
Conservation benefits of marine reserves for fish populations
Authors: Mosquera Iago , Côté Isabelle M. , Jennings Simon , Reynolds John D.
Published: February 2006

We synthesize the results of empirical studies of marine reserves to assess the potential benefits of protection for fish populations. Our meta‐analyses demonstrate that the overall abundance of fishes inside reserves is, on average, 3.7 times higher than outside reserve boundaries. This enhancement is mainly a result of a significant increase in abundance of species that are the target of fisheries. Non‐target species are equally abundant inside and outside reserves. Large‐bodied species also respond more to protection, irrespective of their fishery status. Species within genera show great heterogeneity in their response to protection despite similarities in their life histories. Our study confirms that marine reserves benefit fish populations and highlights the need for monitoring prior to reserve establishment to provide more accurate, habitat‐controlled studies of the effects of marine reserves on fish populations.
Modelling the effects of life‐history traits and changing ecological conditions on the population dynamics and persistence of the endangered Malagasy giant jumping rat (Hypogeomys antimena)
Authors: Sommer S. , Hommen U.
Published: February 2006

We designed an individual‐based model to explore the effects of unusual life‐history parameters and changing ecological conditions on the population dynamics and persistence of the monogamous Hypogeomys antimena, a Malagasy rodent with a recently dramatic decline in its geographical range. Model parameters were derived from extensive field studies carried out since 1992. The simulations predict that Hypogeomys is quite sensitive to small fluctuations in reproductive rate, offspring and adult mortality. Minimum habitat requirements of a viable population that is able to cope for the next 100 years with fluctuating ecological conditions were reached in forest areas of about 3000 ha. However, this habitat size will not represent a stable population. Under current conditions, the population size will continuously decline almost independently of the modelled forest block size. A stable population demography can only be reached by slightly improving the life‐history conditions. The survival prospect of the largest at least partly protected forest fragment currently inhabited by H. antimena are discussed.
Can fluctuating asymmetry be used to detect inbreeding and loss of genetic diversity in endangered populations?
Authors: Gilligan Dean M. , Woodworth Lynn M. , Montgomery Margaret E. , Nurthen Roderick K. , Briscoe David A. , Frankham Richard
Published: February 2006

Fluctuating asymmetry (FA), a measure of developmental stability, has been proposed as a simple technique for identifying populations suffering from inbreeding and a loss of genetic diversity. However, there is controversy regarding the relationship between FA and both allozyme heterozygosity and pedigree inbreeding coefficients (F). FA of sternopleural bristle number in Drosophila melanogaster was measured in populations maintained at effective sizes of 25 (8 replicates), 50 (6), 100 (4), 250 (3) and 500 (2) for 50 generations (inbreeding coefficients of 0.05—0.71). FA was calculated from the same data set using three different indices (FA1, FA5 and FA6). There was no significant relationship of FA with pedigree inbreeding coefficients for any of the three indices. The relationship between FA and allozyme heterozygosity was non‐significant for indices FA5 and FA6 (the more powerful indices) and only significant for FA1. A second comparison of highly inbred (F ∼ 1) populations with their outbred base population showed significantly greater FA in the inbred populations only when analysed with FA6. Analysis of the same data using FA1 and FA5 showed non‐significant relationships in the opposite direction. If a relationship between FA and genetic diversity does exist, it is weak and inconsistent. Consequently, our results do not support the use of FA as a monitoring tool to detect inbreeding or loss of genetic diversity.
The conservation value for birds of cacao plantations with diverse planted shade in Tabasco, Mexico
Authors: Greenberg Russell , Bichier Peter , Angón Andrea Cruz
Published: February 2006

We surveyed birds in cacao (Theobroma cacao) plantations in the state of Tabasco, Mexico. The shade canopy was planted by farmers and consisted of approximately 60 species of trees with no single dominant species. Canopy height averaged 15 m and the structure was multi‐storied. We conducted 220 ten minute, 25 m radius point counts for birds and detected 1550 individuals from 81 species. The average number of birds/point and the expected diversity in a fixed number of individuals within the cacao surveyed were well within the range of other lowland habitats, including agricultural sites, that we have surveyed previously in neighbouring Chiapas. In the Tabascan cacao, the migrant group was composed, in part, of forest species, and dimorphic species were represented primarily by males, which in other areas are known to dominate forest or forest‐like habitats. In contrast to the composition of migrant species, we found few resident forest specialists in Tabascan cacao. Instead, the tropical resident group was composed of large‐bodied generalist species that use small patches of trees in open habitats. These results (moderate diversity, low numbers of forest specialists) differ from the few studies completed in ‘rustic’ cacao systems located near large tracts of forest. The planted shade cacao agroecosystem – at least in the absence of nearby forest – may have a limited value for conserving lost tropical forest bird diversity, but it provides habitat for woodland‐associated migratory species. Our results also indicate that the planted shade cacao plantations supported few small omnivorous or frugivorous species, probably because cacao itself, as well as the dominant shade trees, produce primarily mammal or wind dispersed fruit and seeds.
Biogeographical change in the tiger, Panthera tigris
Authors: Kitchener Andrew C. , Dugmore Andrew J.
Published: February 2006

The number of tiger subspecies is a major conservation issue that is difficult to resolve owing to small fragmented extant populations and limited historical samples in museums, which compromise the rigour of both molecular and morphological taxonomic studies. Rather than considering a static taxonomic approach to geographical variation in the tiger, we consider the changing biogeographical range of the tiger through the last glacial‐interglacial cycle, based on habitat associations of modern tiger specimen records, and environmental reconstructions from the Last Glacial Maximum (LGM; approximately 20000 years before present (B.P.)). We regard this cycle as representative of the numerous glacial cycles that span the evolutionary history of the tiger since its appearance in the fossil record about two million years ago, thereby giving a deep‐time perspective. The key issue is to determine the extent to which ancestral populations of the tiger were geographically isolated. If no geographical isolation is likely, and gene flow between tiger populations could be maintained until modern times, then diagnosably distinct populations could not have evolved. Our reconstructions show that only two tiger populations were likely to have experienced significant geographical isolation from the main species distribution; these were to the west of Tibet (during the LGM) and on Japan (throughout the glacial cycle). In addition, the LGM is likely to have seen the partial separation of peninsular Malayan and Sunda Islands tigers from mainland populations. From a biogeographical perspective it seems probable that only three contemporary populations were sufficiently separated for the evolution of distinct populations, which can be regarded as subspecies or evolutionary significant units. Therefore, most variation in modern tiger populations is probably clinal, which has important implications for future conservation strategies both in the wild and in captivity.
Reintroducing the beaver (Castor fiber) to Scotland: a protocol for identifying and assessing suitable release sites
Authors: Macdonald David W. , Tattersall Françoise H. , Rushton Stephen , South Andy B. , Rao Shaila , Maitland Peter , Strachan Rob
Published: February 2006

The general problem of evaluating the potential success of mammalian reintroduction plans has been tackled by a case study illustrating a four‐phase approach to finding and assessing potential sites for the reintroduction of European beavers, Castor fiber, to Scotland, combining the use of Geographic Information Systems (GIS), fieldwork and population modelling. Phase 1 used GIS to investigate the wider availability of habitat for beavers in Scotland, and predicted that there is the capacity to support in the order of 180 to 390 beaver families. Phase 2 involved the preliminary assessment of nine sites using brief field surveys. Phase 3 focused further on the three most suitable sites, where a thorough habitat survey was used as a basis for calculating carrying capacities of between three and five families. Finally, phase 4 used population modelling to assess the viability and likely spread of beavers following release at these three best sites. High, medium and low parameters were derived from the literature, and populations were predicted to persist and spread as long as at least the medium parameters were used. This exercise illustrates the power of combining field surveys and GIS‐based population modelling as a tool for planning reintroductions in general, and as a foundation for planning the reintroduction of beavers in particular.
Genetic variability and geographic structure of three subspecies of tigers (Panthera tigris) based on MHC class I variation
Authors: Hendrickson Sher L. , Mayer Gregory C. , Wallen Edward P. , Quigley Kathy
Published: February 2006

Genetic variation at the major histocompatibility (MHC) class I loci was examined in captive and wild samples of three subspecies of tiger (Bengal, Panthera tigris tigris; Siberian, P. t. altaica; Sumatran, P. t. sumatrae) by Southern blot analysis using the domestic cat probe FLA 24. All captive populations showed at least moderate variability compared to other felids. Captive tigers were, on average, significantly more variable than wild tigers, but this was not consistent among subspecies. Significant geographic genetic population structure was found at the MHC class I loci among both captive and wild tigers. Phylogenetic analysis of both captive and wild tigers placed Sumatran tigers basally. In a combined phylogenetic analysis, captive and wild tigers of the same subspecies occurred near one another, indicating that the structure of the captive populations reflects that of the wild populations.
Predators and people: using human densities to interpret declines of large carnivores
Authors: Woodroffe Rosie
Published: February 2006

The current extinction crisis is caused primarily by human impacts upon wild populations. Large carnivores are especially sensitive to human activity; because their requirements often conflict with those of local people, predators have been actively persecuted in most regions of the world. In this paper, the impact of people upon predators is analysed by relating local carnivore extinctions to past and projected human population densities. There are strong associations between high human density and the loss of carnivore populations from a region. Interspecific variation in ability to survive at high human densities probably reflects species' ability to adapt to human‐modified habitats. However, regional and temporal variation in individual species' sensitivity to human density is more likely to reflect the activities of local people than the phenotypes of local carnivores. Local culture, government policy and international trade all influence human attitudes to predators and, therefore, the impact of people upon carnivore populations. The importance of these factors may mean that extinction risks for carnivores will continue to increase, even though human population growth is projected to deccelerate during the new millennium. This points to an urgent need for techniques to resolve conflicts between people and predators at either the local or landscape level.
Habitat selection by translocated black howler monkeys in Belize
Authors: Ostro Linde E. T. , Silver Scott C. , Koontz Fred W. , Young Truman P.
Published: February 2006

Habitat selection by translocated black howler monkeys (Alouatta pigra) was studied in Belize, Central America. Ranging patterns of two recently translocated groups were contrasted with those of two groups in the same area with established home ranges, on a yearly and monthly basis. All groups concentrated their activities along stream beds at elevations below 200 m. Newly translocated groups increased the percentage of their monthly ranges in riverine areas (within 100 m of a water source) over the year of the study (with the exception of the last month) while established groups did not. Areas used more than five times by the monkeys contained larger trees and a greater relative coverage of major food species than low‐use areas even though they had a lower overall species richness and diversity. These monkeys may be selecting habitat within the forest based upon vegetative differences and ranging patterns may be affected by patterns of food availability.
Discriminant analysis of the terrestrial and aquatic habitat determinants of the smooth newt (Triturus vulgaris) and the common frog (Rana temporaria) in Ireland
Authors: Marnell Ferdia
Published: February 2006

The breeding site characteristics of the smooth newt (Triturus vulgaris) and the common frog (Rana temporaria) have been investigated in the Republic of Ireland and in Northern Ireland. A total of 278 waterbodies and their surrounding terrestrial habitats were examined in 60 National Grid 10‐km squares across the island: 33 habitat parameters were recorded. Discriminant function analyses were calculated which correctly classified 88.46% and 87.5% of the sites for the newt and frog, respectively. These analyses identified the terrestrial and aquatic habitat variables which were important in discriminating between the sites which were used and unused by each of the species. Terrestrial habitat factors, particularly the availability of terrestrial refugia, were found to be especially important in determining the suitability of the breeding sites for both species.
Comparative demography of red squirrels (Sciurus vulgaris) and grey squirrels (Sciurus carolinensis) in deciduous and conifer woodland
Authors: Kenward R.E. , Hodder K.H. , Rose R.J. , Walls C.A. , Parish T. , Holm J.L. , Morris P.A. , Walls S.S. , Doyle F.I.
Published: February 2006

The demography of red and grey squirrels was studied by live‐trapping and radio‐tagging at 14 deciduous and conifer sites in southern Britain and at eight conifer sites for one year in northern England. Densities and productivity correlated with tree seed crops for both squirrel species in deciduous and conifer habitats. Productivity was reduced by high density of full‐grown squirrels relative to seed abundance. In oak‐hazel woods, demography of grey squirrels correlated with abundance of acorns but not of hazel‐nuts, whereas density and productivity of red squirrels correlated with hazel‐nut abundance. Correlations of female density and productivity with pine‐cone crops did not differ between red and grey squirrels. Predators ate many radio‐tagged grey squirrels in conifers, and annual survival was only 50% compared with 80‐82% for both species in other habitats. Grey squirrel populations in southern conifer sites were sustained by immigration, and at northern sites female density correlated with oak abundance within 500m. Failure to exploit acorn crops puts red squirrels at a competitive disadvantage in deciduous woodland. Red squirrels had higher survival than grey squirrels in conifers, which may give them an advantage in that habitat, but could also have been explained by a lack of predators on their island study site.
Red squirrels (Sciurus vulgaris) released in conifer woodland: the effects of source habitat, predation and interactions with grey squirrels (Sciurus carolinensis)
Authors: Kenward R.E. , Hodder K.H.
Published: February 2006

Fourteen radio‐tagged red squirrels were released in pine woodland containing grey squirrels. Movements of the squirrels were related to the tree species of the donor site. Survival after release was lower than for the grey squirrels: of 11 red squirrels that survived at least a week, only three survived more than three months and none for four months. More than half were eaten or cached by predators, mainly foxes; an experiment with grey squirrel carcasses indicated that they had been killed, not scavenged after death. Hypertrophied adrenals, disease and loss of weight indicated stress as another factor in the deaths. Data on overlap of core ranges, and reluctance of red squirrels to enter traps used by grey squirrels in the mixed population, indicated interference competition between the two species, with grey squirrels possibly dominant. We recommend: (i) that care should be taken to release translocated animals in similar habitat to their origin; (ii) that grey squirrels should be excluded from future release areas until red squirrels have settled and, before biodiversity is reduced by landscape management for red squirrels; (iii) more research to determine whether interactions with grey squirrels or differential predation will ultimately displace red squirrels in conifers.
Circadian metabolic and thermoregulatory patterns of red‐billed woodhoopoes (Phoeniculus purpureus): the influence of huddling
Authors: Boix‐Hinzen C. , Lovegrove B.G.
Published: February 2006

Circadian rhythms of metabolic rate and body temperature were measured in groups of huddling and solitary red‐billed woodhoopoes (Phoeniculus purpureus) as a function of ambient temperature. Basal metabolic rates were 30‐60% lower than those of similar‐sized birds of other species. As a consequence, circadian amplitudes of Tb and VO2 fluctuation between the rest and activity phases of non‐huddling birds were also larger than expected. Circadian rhythms of metabolism save huddling and non‐huddling woodhoopoes 19‐34% of their potential daily energy expenditure. Birds huddling in groups conserved 12‐29% of the daily energy expenditure of non‐huddling birds at ambient temperatures of 20°C and below. However, at 30°C huddling birds used c. 12% more energy than non‐huddling birds. The various avenues of energy conservation employed by woodhoopoes are suggested to be beneficial in: a) augmenting the proximate benefits of cooperative breeding; and b) optimizing fitness in the drought‐prone sub‐Saharan savannahs which are heavily influenced by the El Niño Southern Oscillations.
Establishment of a captive colony of Bettongia tropica (Marsupialia: Potoroidae) by cross‐fostering; and observations on reproduction
Authors: Smith Meredith J.
Published: February 2006

It is demonstrated that cross‐fostering is a practical way of improving the rate of increase of a rare species in captivity. Two adult Bettongia tropica were captured in northern Queensland and housed in captivity in Adelaide, South Australia. Eleven pouch young born in captivity to the wild‐caught B. tropica were transferred at 20 days old or older to B. penicillata foster mothers and nine were reared successfully. Of a further 10 young not fostered, six were reared by the wild‐caught mother. Fostering allowed the wild‐caught female to produce surviving young nearly twice as frequently as if she had reared them in her pouch.

Sexual maturity occurred at 246‐523 days (x[bar] = 407.2 ± 59.9 days) in 4 males and at 185‐429 days (x[bar] = 300.5 ± 26.0 days) in 11 females. Breeding continues throughout the year and females undergo embryonic diapause whilst supporting a pouch young. The female reproductive system is remarkable for its relatively long urethra and lateral vaginae and consequently short urogenital sinus. The male reproductive system is unremarkable, having a carrot‐shaped prostate gland and three pairs of Cowper's glands, as do many other macropodoid species. Two pairs of paracloacal glands are found in males and females.
The colony structure and social organization of the giant Zambian mole‐rat, Cryptomys mechowi
Authors: Wallace E. D. , Bennett N. C.
Published: February 2006

Cryptomys mechowi is a social subterranean mole‐rat which inhabits the mesic regions of south‐eastern and central Africa. Giant mole‐rats live in colonies of up to 11 animals in which reproduction is normally restricted to the largest male and female in the colony. In this preliminary study on a laboratory‐reared colony, the non‐reproductive members of the colony could not be placed into clearly defined, work‐related groups based on body mass. The colony showed a work frequency related division of labour. Reproductive animals performed little work, 3‐4% of the total work. The non‐reproductive caste was divided into two groups based on the amount of burrow maintenance activity: those performing between 7‐11% of total work and those ranging from 15‐22% of total work. Male members of the colony tended to perform more work than the females. The dominance hierarchy of the colony was found to be nearly linear, with a value of 0.83 calculated from Landau's linearity index. The reproductive animals were the most dominant in their respective gender. Dominance was not age‐related. However, non‐reproductive males tended to be more dominant than non‐reproductive females. Social organization within the giant Zambian mole‐rat is compared with other southern African Cryptomys species in the light of the eusociality continuum.
The reproductive cycle and determination of sexual maturity in male brown long‐eared bats, Plecotus auritus (Chiroptera: Vespertilionidae)
Authors: Entwistle A. C. , Racey P. A. , Speakman J. R.
Published: February 2006

Observations of the external morphology of wild‐caught and captive male brown long‐eared bats (Plecotus auritus) revealed a marked seasonal pattern of spermatogenesis, similar to that established by histological examination of other temperate‐zone vespertilionids, with a peak in testes size in August and a lag between testicular growth and epididymal distension. This was followed by complete cessation of spermatogenesis and shrinkage of the testes to prepubertal size. The period of peak spermatogenesis coincided with a reduction in the incidence of torpor and also a decline in body mass. This suggests that torpor and spermatogenesis may be incompatible in this species. Outside the season of testicular growth and epididymal distension, sexual maturity could not be confidently determined in P. auritus by the pigmentation of the tunica vaginalis surrounding the epididymis, a characteristic which has become established in other species. Instead, the size and shape of the caudae epididymides appeared to be a better criterion for defining sexual maturity in this species. Most males underwent testicular growth and epididymal distension, and were assumed to have reached sexual maturity, at an age of 15 months. However, some individuals (29%), particularly those in good condition (relatively heavy individuals), showed a degree of testicular and epididymal development in their first autumn, i.e. at 3 months of age, indicating that the onset of puberty may be dependent on body condition. Poor body condition was associated with delayed spermatogenesis in adult males.
Intraspecific scarring in odontocete cetaceans: an indicator of male ‘quality’ in aggressive social interactions?
Authors: MacLeod Colin D.
Published: February 2006

The level of visible (i.e. white or unpigmented) scarring on cetaceans varies greatly between species, particularly for intraspecific scarring in odontocete cetaceans. In some species, unpigmented intraspecific scars may act as an indicator of male ‘quality’ during aggressive social interactions. Evidence to support this hypothesis was found in 18 species of odontocete cetacean. These were the narwhal (Monodon monoceros), the sperm whale (Physeter macrocephalus), the Risso's dolphin (Grampus griseus) and the family Ziphiidae (with the exception of Mesoplodon ginkgodens). The evolution of such signalling is related to the fact that teeth are not required for feeding on certain diets, primarily cephalopod‐based diets, and as a result the number of teeth has been reduced. However, some teeth have been retained, and selected, as weapons for male‐male competition. This has resulted in an increase in the level of intraspecific scarring and the greater need for a signal of ‘quality’ to avoid costly and dangerous fights. As intraspecific scarring became this signal, the repigmentation rate of scars was reduced, leading to all scars remaining permanently unpigmented in these species.
A new genus and three new species of deep‐sea holothuroids from the west coast of South Africa (Echinodermata)
Authors: Thandar Ahmed S.
Published: February 2006

One new genus and three new species of deep‐sea holothuroids, taken by the South African Division of Sea Fisheries R.S. Africana II routine trawls, off the west coast of the Cape Peninsula in South Africa in 1959, are described. A new genus Psolidothuria, perhaps referable to the dactylochirotid family Vaneyellidae, is erected for the new species P. octodactyla. The remaining new species are Paracucumaria capense, in the dendrochirotid family Cucumariidae, and Laetmogone perplexa, in the elasipodid family Laetmogonidae. P. capense was originally described as Trachythyone parva (Ludwig) by Thandar (1991). The diagnosis of the family Vaneyellidae is amended to accommodate the new genus.
Habitats of the song thrush Turdus philomelos in a largely arable landscape
Authors: Mason C. F.
Published: February 2006

During three breeding seasons, 1994‐96, the habitats of song thrushes were studied in north‐east Essex, U.K., in 10 tetrads (total 40 km2) of mainly farmland habitat and 35 woods of differing sizes (range 0.1‐57.0 ha). Within tetrads, only 6 (3.5%) territories were found in farmland. Gardens held 123 (71.5%) territories, though this habitat made up only 2% of the total area, while 39 (22.7%) were in woodlands (1% of total area). Population densities were much lower in the tetrads than in earlier studies; this may be an indication of the severe population decline that the species has recently undergone. Densities in gardens differed less from those of previous studies.

In the woodland study, the number of woods holding song thrush territories declined over the three years, while the proportion of total territories in the six largest woods increased. Densities in the woods were lower than those reported in earlier studies but the disparity was not as great as in farmland. Extinctions in the smaller woods was 20‐30% per annum, a rate similar to that for gardens: population extinctions did not occur in the larger woods.

Some 40% of non‐garden territories in the surveys of both tetrads and woodland plots were within 100 m of a garden. Gardens may be currently acting as a refuge for song thrushes and an understanding of the ecology of the species in different types of gardens may be important in current conservation efforts for the species.
Predatory behaviour and parental care in Argyrodes flavipes, a social spider from Queensland
Authors: Whitehouse M. E. A. , Jackson R. R.
Published: February 2006

Argyrodes flavipes illustrates a novel form of highly social behaviour in spiders. Although A. flavipes lives in groups, forages communally, and has parental care, it is also highly aggressive towards conspecifics. These observations, plus the relatively small group sizes, suggest that sociality in these animals may be more akin to that in social mammalian carnivores than in social insects. Most highly social spiders are thought to have developed sociality via the sub‐social route because of their high level of parental care. Although A. flavipes also exhibits high levels of parental care, its phylogenetic background and the fact that it needs to defend its young from conspecifics, suggest that both sub‐social and para‐social factors may have influenced its social development.