Estimating population size of endangered brush-tailed rock-wallaby (Petrogale penicillata) colonies using faecal DNA

The brush-tailed rock-wallaby (Petrogale penicillata) is an endangered species in southeastern Australia and many of the remaining populations are declining. The steep rocky habitat and shy nature of the species make it difficult to obtain data on population parameters such as abundance and recruitment. Faecal pellet counts from scat plots are commonly used to monitor population trends but these are imprecise and difficult to relate to absolute population size. We conducted a noninvasive genetic sampling 'mark-recapture' study over a 2-year period to identify individuals from faecal DNA samples and estimate the population size of four brush-tailed rock-wallaby colonies located in Wollemi National Park, New South Wales. Scat plots in rock-wallaby colonies were used as sample collection points for this study. Two separate population estimates were carried out for three of the colonies to determine if we could detect recruitment and changes in population size. We determined that there was one large colony of an estimated 67 individuals (95% confidence interval: 55-91) and three smaller colonies. Monitoring of the smaller colonies also detected possible population size increases in all three. Our results indicate that faecal DNA analysis may be a promising method for estimating and monitoring population trends in this species particularly when used with a traditional field survey method.     

BIOLOGY AND BEHAVIOUR OF FRIGATEBIRDS FREGATA SPP. ON ALDABRA ATOLL

Both species nested in mixed colonies in mangrove trees. The tops of trees were usually occupied exclusively by minor and the lower parts by ariel, but most nests of both species were in the intermediate parts of the canopy. The main laying season for both species was July to January. A census showed about 27 000 individuals present at the height of the season (1500 breeding pairs of minor, 5350 of ariel). Seasonal variation in numbers could be accounted for almost entirely by the changes in breeding activity of a resident population. Young of both species were fed at or near the nest-site for at least four months after fledging. A recovery near Bombay of a wing-tagged immature ariel shows that this species, at least, undergoes a post-fledging dispersal; it is suggested that young minor either do not disperse, or do so later than ariel. Food samples collected from chicks showed no overall difference between the species, but a seasonal analysis showed that ariel took more squid than minor in the wet season, and in the dry season the two species took different proportions of the two commonest species of flying-fish. Chicks of ariel received smaller meals than minor chicks in the wet season, but similar-sized meals in the dry season; ariel chicks grew more slowly than minor chicks. It is suggested that the timing of the breeding season is related to the need for adults to build up fat reserves to carry them through the courtship, nest-building and laying periods, when they are tied to the colony and so have little opportunity to feed. The evidence for non-annual breeding in frigatebirds is discussed. It is concluded that while successful breeders must breed at intervals of more than 12 months, they could theoretically nest in two successive seasons and that, since breeding success is low, most individuals probably do so. Existing knowledge of the biology of four of the five recognized species of frigatebirds is summarized, and shows that the family is at least as uniform as the tropicbirds and much more so than other Pelicaniformes.     

Parentage analysis in Gabonese colonies of soil-feeding termites belonging to the Cubitermes sp. affinis subarquatus complex of species (Termitidae: Termitinae)

Abstract Cubitermes spp. are widely distributed soil-feeding termite species in sub-Saharan Africa which play a fundamental role in soil structure and fertility. A complex of at least four cryptic species (i.e., Cubitermes sp. affinis subarquatus complex of species) has been recently described using molecular markers. In order to investigate the breeding system of these species, five microsatellite markers were used to carry out parentage and relatedness analyses in 15 Gabonese colonies. Monogamy was confirmed as the predominant reproductive organization in Cubitermes spp. (76% of the colonies). Within 30% of these monogamous colonies, a high relatedness between reproductives was shown, suggesting that mating between related individuals occurs. However, Cubitermes colonies can deviate from monogamy. Indeed, parental contributions by at least two related reproductives of the same sex were revealed in four colonies and polyandry was demonstrated in two of them. Infiltration of reproductives in the colony is the most plausible explanation for such cases of polygamy in Cubitermes spp.     

Isolation and characterization of highly polymorphic microsatellite loci for the garden tiger moth Arctia caja (Lepidoptera: Arctiidae)

A set of microsatellite markers was isolated from Arctia caja, a species that has been declining in UK for several decades. As has been found with other Lepidoptera species, this proved to be a difficult task. Eight enriched libraries identified 103 positive clones, and these yielded only seven polymorphic microsatellites. Allelic diversity ranged from 10 to 23 alleles per locus in a population of 30 individuals. Significant heterozygosity deficits were shown by three of these loci, presumably due to null alleles. The remaining four loci were in Hardy–Weinberg equilibrium and will be used to investigate the population genetic structure of A. caja.     

Cooperation in the neotropical pseudoscorpion, <Emphasis Type="Italic">Paratemnoides nidificator</Emphasis> (Balzan, 1888): feeding and dispersal behavior

Social behavior is rare among arachnids, and “permanent-sociality” is a strategy documented only in a few spider species. Here we describe the feeding and dispersal behavior of Paratemnoides nidificator, a Neotropical pseudoscorpion presenting “non-territorial permanent-sociality”. Field and laboratory observations (100 hours and 200 sessions over four years) and manipulative experiments revealed that P. nidificator is a generalist predator that lives in rough bark of trees, in groups of 2 to 175 individuals (42.62 ± 28.27; N=35 colonies; solitary individuals were never found), including reproductive adults and nymphs. Individuals in groups cooperatively capture prey four times larger than solitary individuals. Adult hunters share food with siblings. Reproduction in natural conditions occurs during the hot/wet season, when food availability is high. Prey diversity and abundance seem to be the main factor limiting reproduction in this species. Phoresy (attachment to a transporter animal) is the basic mode of dispersion in P. nidificator. Grouped individuals use large animals as vectors for dispersal, and once established they use the vector as the first food item of the new colony. However, they can also disperse by colony fission, newly documented herein for this taxon. The elaborate, cooperative behavior in P. nidificator is unique among pseudoscorpions and represents an excellent model for studies on the evolution of sociality in invertebrates. Received 10 August 2006; revised 17 November 2006; accepted 23 January 2007.     

Feeding selectivity of introduced hedgehogs <Emphasis Type="Italic">Erinaceus europaeus</Emphasis> in a dryland habitat,South Island,New Zealand

We describe the diet of introduced European hedgehogs Erinaceus europaeus (Linnaeus, 1758) in a New Zealand dryland system and provide the first quantitative analysis of food selectivity for this species. We also describe and compare the diets of nine hedgehogs and measure dietary overlap between these individuals. The most commonly eaten foods were beetles, including rare native species (in 94% of droppings), earwigs (92%), spiders (25%) and native skinks (14%). Remains of at least three skinks were found in one dropping. Earwigs and darkling beetles (Tenebrionidae) were the most preferred food types, and Hymenoptera and cylindrical bark beetles (Colydiidae) were least preferred. Consumption of most foods mirrored their availability. Most individuals’ diets conformed to the pattern seen at the population scale, with 21–54% of dry faecal mass derived from beetles and 13–39% from earwigs. One animal frequently consumed large amounts of fruit. Dietary overlap between pairs of individuals was high (mean Horn’s index, 0.84). This may be the result of limited opportunities to diversify in a very moisture-limited and low diversity habitat.     

Potential genetic consequences of a recent bottleneck in the Amur tiger of

The Amur tiger, Panthera tigris altaica, is a highly endangered felid whose range and population size has been severely reduced in recent times. At present, the wild population is estimated at 490 individuals, having rebounded from the 20–30 tigers remaining following a severe bottleneck in the 1940's. The current study presents preliminary data on the patterns and levels of genetic variation in the mitochondrial DNA control region using DNA extracted from non-invasively sampled faecal material, collected throughout the entire range of P. t. altaica in the Russian Far East. Analysis of 82 scat samples representing at least 27 individuals revealed extremely low levels of CR haplotype diversity, characterized by a single widespread haplotype (96.4%) and two rare variants, each differing by a single step within the hypervariable I (2.4%) and central conserved regions (1.2%), respectively. A comparison with previous data on cytochrome bvariation in 14 captive individuals revealed a potentially greater amount of genetic variation represented in captivity relative to that found in the wild population. The extremely low levels of mitochondrial DNA variation in the wild population is discussed in light of the demographic processes that might have shaped these patterns as well as the potential bias introduced through analysis of fecal samples. These results highlight the continuing need to assess levels of genetic variation even in recovering populations that are increasing in number and underscore the important role that captive breeding programs may play in preserving remnant genetic diversity of endangered species.     

Lysine and glutamate transport in the erythrocytes of Common Brushtail Possum, Tammar Wallaby and Eastern Grey Kangaroo

It was recently coincidentally discovered, using ¹H NMR spectroscopy, that the erythrocytes of two species of Australian marsupials, Tammar Wallaby (Macropus eugenii) and Bettong (Bettongia penicillata), contain relatively high concentrations of the essential amino acid lysine (Agar NS, Rae CD, Chapman BE, Kuchel PW. Comp Biochem Physiol 1991;99B:575–97). Hence, in the present work the rates of transport of lysine into the erythrocytes from the Common Brushtail Possum (Dactylopsila trivirgata) and Eastern Grey Kangaroo (Macropus giganteus) (which both have low lysine concentrations), and Tammar Wallaby were studied, to explore the mechanistic basis of this finding. The concentration-dependence of the uptake was studied with lysine alone and in the presence of arginine, which may be a competitor of the transport in some species. In relation to GSH metabolism, glutamate uptake was determined in the presence and absence of Na⁺. The data was analysed to yield estimates of the maximal velocity (V_max) and the K_m in each of the species. Erythrocytes from Tammar Wallaby lacked saturable lysine transport in contrast to the other two species. The glutamate uptake was normal in all three animals for adequate GSH biosynthesis.     

The release of captive bred snails (Partula taeniata) into a semi-natural environment

A population of zoo bred Partula taeniata was released into a patch of native Polynesian plants in the Palm House at the Royal Botanic Gardens, Kew, London, UK. The released snails were from a colony established from wild-caught snails in 1982, which had been in captive conditions for up to six generations. Monitoring of the snails was continuous and intensive for the first 2 weeks, and at decreasing frequency over the next 15 months. There was high survivorship early on in the release, but once the intensive monitoring ended survivorship became hard to determine due to difficulties in locating snails in the large and complex habitat. However, snails are known to have persisted for at least 15 months, and new individuals have been noted maturing into all developmental stages. The snails exhibited patterns of feeding and microhabitat choice similar to those observed in the wild, despite being reared in a highly artificial environment. The methods and results provide some guidelines for future release trials for this highly endangered group of snails.     

Bottom‐up processes in a declining yellow‐footed rock‐wallaby (Petrogale xanthopus celeris) population

Populations of large herbivores are generally considered to be food limited, escaping the regulatory effects of predation through their large body size, migratory behaviour and/or the occurrence of alternate prey species. In the Australian arid and semi‐arid zones, the availability of forage biomass is considered to be the primary driver of fluctuations in kangaroo abundance. However, little is known about the population dynamics of the smaller sympatric macropods. We examined the demographic traits of a large colony of yellow‐footed rock‐wallabies (Petrogale xanthopus celeris), following a 2‐year period of above average rainfall. The population was located within a conservation reserve that was subject to a predator control program around its perimeter and on neighbouring properties. The low predator abundance provided an opportunity to gauge the strength of bottom‐up population processes. During the two years of the study, the population declined in size by 53%, resulting from both the virtual absence of juvenile recruitment and the loss of adult wallabies. Although reproductive output was high, low pouch young and juvenile survival rates resulted in few individuals progressing into the adult population. With minimal recruitment, the rate of population decline (r = 0.77) matched the observed adult survival rate (Φ = 0.76). Despite average rainfall conditions during the study, survival rates across all age‐classes were equivalent to those reported for other rock‐wallaby populations during periods of scarcity. The reduced survival rates were attributed to low levels of forage resources, particularly around the wallabies' refuge sites, suggesting the bottom‐up regulation of the colony at high densities. The data suggest that the colony was at temporarily high abundance, following a rainfall driven pulse of recruitment. Conservation management actions for this species should focus on increasing juvenile survival rates within declining populations, through the control of feral goats (Capra hircus), rabbits (Oryctolagus cuniculus) and red foxes (Vulpes vulpes).     

Successful care and propagation of the endangered amargosa vole (Microtus californicus scirpensis) in captivity

The Amargosa vole (Microtus californicus scirpensis) is a highlyendangered rodent endemic to a small stretch of the California portion of the Amargosa River basin in Inyo County's Mojave Desert. Although the Amargosa vole has survived in this naturally fragmented ecosystem for thousands of years, recent habitat degradation due to land development, water drainage, and marsh exploitation has further isolated the species and reduced its available habitat. As part of a conservation effort to preserve the species, a captive breeding population was established in 2014 to serve as an insurance colony and as a source of individuals to release into the wild as restored habitat becomes available. As this is the only captive colony for this species, there is little published information about appropriate care and husbandry for the Amargosa vole. Here we provide information about behavior, diet, reproduction, drug sensitivities, and diseases that affect successful captive care. We also provide recommendations for housing and disease management to preserve natural behaviors and defenses in captive‐born animals.     

Predation by cats could lead to the extinction of the Mediterranean endemic Yelkouan Shearwater Puffinus yelkouan at a major breeding site

Feral cats are considered to be one of the main harmful invasive species for island species. Adult shearwaters are highly vulnerable to predation by cats. The population of the Yelkouan Shearwater Puffinus yelkouan, a species endemic to the Mediterranean, is predicted to decline, leaving only a few large breeding colonies, due to the invasion of cats. The impact of cats on the Shearwater population of Le Levant Island, one of the major breeding sites for this species, was evaluated by studying cat diet over a 2‐year period. The predation rate obtained was then included in a Shearwater demographic model. Cats preyed upon rabbits, rats and Shearwaters, with a peak of predation on Shearwaters immediately upon their arrival at the colony. Cat predation was heavy and responsible for the yearly death of about 810–3241 birds. This could lead to the extinction of the Le Levant colony within the next four decades and perhaps within just a few years. Cat predation on prospecting individuals, a parameter essential to assess the real impact of predation, may not have an immediate effect on the Shearwater breeding population but can accelerate population extinction. Cat predation must be reduced or removed to prevent the extinction of one of the most important breeding sites for this species.     

Avian fruit consumption and seed dispersal in a temperate Australian woodland

Abstract The effectiveness of avian fruit consumers as seed dispersers of fleshy‐fruited plants was studied in a temperate woodland community. As a consequence of the short and overlapping fruiting phenologies of fleshy‐fruited plant species in temperate regions of Australia, there are very few avian species that are true specialist frugivores. The relative importance of bird species as fruit consumers was investigated, and how their foraging activities, movements and gut treatment of seeds affected dispersal of viable seeds away from the parent plant was examined. Fruit consumption and consumer seed dispersal capacity were assessed in this study through faecal analyses and by testing the viability of seeds that had passed through the gut of avian consumers. Behavioural observations enabled us to determine the consumption rates of, and quantities of fruit consumed by, various bird species and the amount of time spent feeding. Silvereyes (Zosterops lateralis) were the dominant fruit consumers in the community, although 19 bird species were either observed consuming fruit or provided faecal samples that contained fruit. Silvereyes had a high local abundance at the site and more than 90% of silvereyes’faecal samples contained the seeds of fruiting plants (n = 409). Large numbers of fruit were consumed per visit by silvereyes, particularly for Rhagodia parabolica (fragrant saltbush). Silvereyes consumed an average of four R. parabolica fruit per 5 s and up to a maximum 40 fruit per visit. Viability was high for seeds recovered from silvereyes’faeces (R. parabolica, 94.4% viable; Hymenanthera dentata, 100% viable). However, the number of seeds per faecal sample was high for R. parabolica, which may result in density‐dependent seed mortality. Gut passage rate for silvereyes fed R. parabolica fruit in captivity was 31.5 ± 1.9 min. Silvereyes remained at fruiting plants for very short periods (average 50‐60 s) and in most cases moved away from the parent plant, primarily toward canopy trees. Given the short visit duration of silvereyes, individuals would have left the parent plant well before seeds passed through the gut. Rhagodia parabolica fruit was consumed by a large number of bird species in the community, including species often thought of as exclusively insectivorous or nectarivorous. These species are likely to disperse viable R. parabolica seeds into microhabitats different from those visited by silvereyes.     

SOME RESULTS OF BIRD-BANDING IN THE CONGO (KINSHASA)

The global Blue Swallow Hirundo atrocaerulea was classified as Vulnerable in 2010 on account of its small and rapidly declining population estimated at less than 1 500 pairs. We undertook this study to gain a better understanding of the current status and threats facing this migratory species. Three previously unknown areas that might be part of the species' non-breeding range were identified in Kenya and northern Tanzania. Within its breeding range we identified three previously unknown areas of potentially suitable habitat, one in Tanzania and two in Malawi, which require further exploration. Population viability assessment predicted that the Blue Swallow population will decline by 8% in 10 years. The overall probability of extinction of the species in the wild is 3%. Minimum viable population size analysis suggests that a goal for the long-term conservation of the Blue Swallow should be to mitigate current threats that are driving declines such that the population increases to a minimum of 3 600 individuals. This should consist of at least 900 individuals in each of the four clusters identified, along with a minimum of 500 individuals in at least one of the meta-populations per cluster. The four clusters are located in (1) the southeasten Democratic Republic of the Congo, (2) highlands of southern Tanzania and northern Malawi, (3) eastern highlands of Zimbabwe and (4) South Africa and Swaziland. The current proportions of the Blue Swallow population in strictly protected and unprotected areas on their breeding grounds are 53% and 47%, respectively, whereas on their non-breeding grounds the corresponding percentages are 25% and 75%, respectively. Our reassessment of the Blue Swallow's risk of extinction indicates that it continues to qualify as Vulnerable according to the IUCN/SSC criteria C2a(i).     

Faeces as a source of DNA for molecular studies in a threatened population of great bustards

With recent advances in molecular biology, it is now possible to use the trace amounts of DNA in faeces to non-invasively sample endangered species for genetic studies. A highly vulnerable population of approximately 100 great bustards (Otis tarda) exists in Morocco necessitating the use of non-invasive protocols to study their genetic structure. Here we report a reliable silica-based method to extract DNA from great bustard faeces. We found that successful extraction and amplification correlated strongly with faeces freshness and composition. We could not extract amplifiable DNA from 30% of our samples as they were dry or contained insect material. However 100% of our fresh faecal samples containing no obvious insect material worked, allowing us to assess the levels of genetic variation among 25 individuals using a 542 bp control region sequence. We were able to extract DNA from four out of five other avian species, demonstrating that faeces represents a suitable source of DNA for population genetics studies in a broad range of species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rapid recovery of Dutch gray seal colonies fueled by immigration

Gray seals were first observed breeding in the Dutch Wadden Sea in 1985, after centuries of absence. The breeding colony there is now the largest on the European continent. We describe the changes in gray seal numbers and their geographical expansion, and estimate how these processes were influenced by immigration from other colonies. Counts of hauled out animals were carried out between 1985 and 2013, monitoring three different periods of the seals' annual cycle. Using priors determined for the UK population, a Bayesian demographic model was fitted to pup numbers to estimate the population parameters driving the growth. This included immigration of subadults into the breeding population, which contributed to an average growth rate in the pup counts of 19%/yr, much higher than expected in a closed population. This immigration may account for approximately 35% of the total annual growth. In addition, at least 200 gray seals from the UK visit the area temporarily. Recovery of the population in the Netherlands occurred more than 50 yr after gray seals were protected in the UK. These time scales should be taken into account when studying long living marine mammals, e.g., in impact and conservation studies.     

Dispersal in the inquiline social parasite ant Plagiolepis xene

Inquiline ants are highly specialised social parasites. They usually do not produce their own worker caste but instead use the worker force of the host ant colony to ensure the rearing of their sexual progeny. Several barriers are expected to severely limit their migration, and the mechanism allowing them to disperse remains largely enigmatic. Here, we tested two hypotheses to account for the low level of infestation of inquiline parasites, in populations of the parasite ant Plagiolepis xene and its host P. pygmaea: (1) the establishment of a new P. xene colony is such a rare event that a single colonisation should be expected per population, and (2) once a P. xene colony is established in one location, it has very little chance to succeed in infecting a neighbour genetically unrelated colony. We sampled nests from both species along four separate transects, and genotyped host and parasite individuals at eight polymorphic microsatellite loci. Our genetic data contradict both hypotheses: multiple colonisation events were recorded in all four transects sampled and, in at least one case, P. xene has successfully migrated from one host colony of P. pygmaea to a spatially close unrelated nest. This shows that the dispersion capacity of the social parasite is sufficiently effective to ensure its long-term survival.     

The first record of the swordtail Xiphophorus hellerii Heckel, 1848 (Poeciliidae,Actinopterygii) established in the wild from Morocco

Aquarium and ornamental fish trade is currently recognized as a major source of invasive species in aquatic ecosystems around the world. The swordtail Xyphophorus hellerii is a popular ornamental freshwater fish that occurs as an introduced species in the aquatic habitats of at least thirty-one countries. We report the first finding of an established population of the swordtail in Morocco. Twelve individuals of X. hellerii were captured along Oued Ain Chkef inside the park (Fez Province), including females and males (mature and immature). Ongoing investigations could soon reveal more occurrences of this species in the country.     

Breeding performance of gentoo penguins (Pygoscelis papua) at a colony exposed to high levels of human disturbance

Port Lockroy, situated on the Antarctic Peninsula, is one of the most visited tourist sites in Antarctica. The effects of visitor disturbance on the breeding performance of gentoo penguins (Pygoscelis papua) at Goudier Island, Port Lockroy was investigated during the austral summer of 1996/1997 by comparing pairs in treatment areas (visited by 35–55 tourists every 1–2 days) and control colonies (not visited by tourists). There were no differences between the two groups in the proportion of birds that laid, in hatching success or the proportion of single-chick broods. Pairs in treatment colonies laid a higher proportion of single-egg clutches, but this was related to colony location and unusually high snow accumulation. Most treatment colonies were situated on low-lying ground or in the lee of buildings, and probably had more late layers at the initial census. Only 11% of tourist visits had occurred by laying, making human disturbance an unlikely explanation for the higher proportion of single-egg clutches. Nests monitored in a disturbed colony and a control colony showed no differences in chick mass or survival up to 20 days of age. The overall breeding success, based on counts of creched birds, was similar to other southern populations of gentoo penguins, after correcting for mortality between creching and fledging. Historical data from Goudier Island indicate that the colony established itself in 1985 and has rapidly increased in size since then. The neighbouring colony at Alice Creek, which has been regularly visited by tourists for at least a decade, has also shown a population increase, although this expansion has been at a slower rate. We conclude that disturbance from tourist visits is unlikely to have been a major determinant of gentoo population change at Port Lockroy. Accepted: 8 November 1998