Dominance and population structure of freshwater crabs (Potamonautes perlatus Milne Edwards)

Although freshwater crabs, Potamonautes spp, are abundant (up to 23 crabs m-2) in southern African freshwater systems and form a major part of the diet of many vertebrates, little is known about their biology. Understanding crab population dynamics and behaviour, for example, is important to understanding their role in the ecosystem more clearly. In this paper we report on dominance in Potamonautes perlatus and test the prediction that larger crabs are dominant to smaller ones, i.e. a linear hierarchy exists and it is size dependent. To understand how this would affect wild populations we also investigated the population structure (sex ratio, size distribution, density and population growth) of a wild population. Using Landau's index of linearity (h) we found three captive groups of P. perlatus to show moderate linearity, i.e. h = 0.9; 0.81 and 0.83. In all three groups the largest individual was the most dominant. There was a significant Spearman rank correlation between dominance rank and size of largest chelae in two of the groups, and a significant Spearman rank correlation between dominance rank and carapace width in only one of the three groups. Densities of crabs in the Eerste River, Western Cape Province, ranged from a mean of 2.89 ±2.11 to 15.57 ± 7.21 crabs m-2. Unexpectedly the size class distribution of the crabs remained unchanged during the year. The lack of a significant increase in the mean size of the crabs can probably be ascribed to a year-round consistency in the availability of refugia for specific/different size classes. Intraspecific aggression, predation and refuge availability are probable strong selection pressures in determining population structures of wild populations of P. perlatus.Keywords: Dominance. linear hierarchy, population structure, refuge availability, rivers, South Afric

Ambiguity in guideline definitions introduces assessor bias and influences consistency in IUCN Red List status assessments

The IUCN Red List is the most widely used tool to measure extinction risk and report biodiversity trends. Accurate and standardized conservation status assessments for the IUCN Red List are limited by a lack of adequate information; and need consistent and unbiased interpretation of that information. Variable interpretation stems from a lack of quantified thresholds in certain areas of the Red List guidelines. Thus, even in situations with sufficient information to make a Red List assessment, inconsistency can occur when experts, especially from different regions, interpret the guidelines differently, thereby undermining the goals and credibility of the process. Assessors make assumptions depending on their level of Red List experience (subconscious bias) and their personal values or agendas (conscious bias). We highlight two major issues where such bias influences assessments: relating to fenced subpopulations that require intensive management; and defining benchmark geographic distributions and thus the inclusion/exclusion of introduced subpopulations. We suggest assessor bias can be reduced by refining the Red List guidelines to include quantified thresholds for when to include fenced/intensively managed subpopulations or subpopulations outside the benchmark distribution; publishing case studies of difficult assessments to enhance cohesion between Specialist Groups; developing an online accreditation course on applying Red List criteria as a prerequisite for assessors; and ensuring that assessments of species subject to trade and utilization are represented by all dissenting views (for example, both utilitarian and preservationist) and reviewed by relevant Specialist Groups. We believe these interventions would ensure consistent, reliable assessments of threatened species between regions and across assessors with divergent views, and will thus improve comparisons between taxa and counteract the use of Red List assessments as a tool to leverage applied agendas.University of Bangor, University of Pretoria, CIB, the Scientific Authority of the South African National Biodiversity Institute

Food, family and female age affect reproduction and pup survival of African wild dogs

Understanding factors that affect the reproductive output and growth of a population of endangered carnivores is key to providing information for their effective conservation. Here, we assessed patterns in reproduction for a small population of endangered African wild dogs (Lycaon pictus) over 90 pack years. We tested how availability of prey, pack size, pack density, rainfall, temperature and female age affected the age of first litter, litter size and pup survival. We found that females bred younger when pack density, availability of prey and pack size were large.We also found that fecundity increased significantly with age while the population was male biased only for 1-, 2- and 4-year olds. Larger litters were produced by larger packs, suggesting strong reproductive benefits of grouping related to cooperative hunting and food provisioning for helpers and alpha females. We also found an interaction between breeding female age and pack size where older females in large packs raised a high proportion of pups. Additionally, large litters and large packs were important for raising a greater number of pups to 6 and 12 months, respectively, suggesting that while litter size is important for pup survival, the benefits of a large pack are only realised when pups are older and mobile with the pack. Collectively, these results illustrate the novel finding that prey availability is critically important in initiating reproduction inwild dogs and that the number of non-breeding helpers, female age and litter size is essential to pup survival

Density of leopards Panthera pardus on protected and non-protected land in the Waterberg Biosphere, South Africa

Data on the population size and trends of large carnivores remains the cornerstone of effective management and conservation programs. However, such data are rarely available for the majority of large carnivore species. Furthermore, large carnivore research is often directed towards formally protected areas. There is therefore a need to improve our knowledge regarding the population ecology of large carnivores in non-protected areas. In this study we use camera trapping in conjunction with spatially explicit mark–recapture models to estimate leopard Panthera pardus density across different land use types in the Waterberg Biosphere, South Africa. Estimated densities (mean SE) ranged from 6.59 ( 5.2/100 km²) on a matrix of commercial game and livestock farms to 5.35 ( 2.93/100 km²) and 4.56 ( 1.35/100 km²) on two protected areas (Lapalala and Welgevonden respectively). Although density estimates had large confidence intervals we suggest that these results indicate similar densities across the three sites. These results support other studies suggesting that non-protected areas can harbour as dense leopard populations as protected areas, and can therefore not be neglected in the management of leopards.Funding for the project was received from the IFS (D/4984-1), Wild Foundation (2008-011), Wilson Foundation and the University of Pretoria. LHS was further supported by the NRF (no. 74819 and no. 88179), FD by a research fellowship from the Univ. of Pretoria, the National Geographic Society/Waitts foundation (w32-08) and the NRF, and MJS by the DST-NRF Centre of Excellence for Invasion Biology and the NRF

An assessment of spatial and temporal variation in the diet of Cape clawless otters (Aonyx capensis) in marine environments

We studied the diet of Cape clawless otters (Aonyx capensis) at three sites along the eastern and southern coast of South Africa to assess possible spatial variation along a community species richness and biomass gradient associated with rocky shores.A total of 309 spraints representing two seasons (summer 2013/2014 and winter 2014) were collected and subsequently analysed. The percentage occurrence and percentage dry mass of numerous prey categories were compared between sites and seasons. Variation in the importance of prey items was found between sites, whilst no variation was found between seasons within the same site. Crab was the most important prey item in the southernmost study area (Tsitsikamma National Park) and at the northernmost study site (KwaZulu-Natal Coast), whilst lobster was the most important prey item in the central area (Mkambati Nature Reserve). Fish was the second most important prey item at all three sites. Our results suggest that otters are opportunistic feeders that are likely able to adapt to potential prey species and abundance changes associated with current and future anthropogenically driven changes. Furthermore, long-term, site-specific stability in diet suggests that monitoring the diet of otters could provide some useful information on the status of shoreline communities

Pre-release hunting training and post-release monitoring are key components in the rehabilitation of orphaned large felids

The rehabilitation of orphaned animals is commonly practiced but rarely scientifically documented. The behavioural development before release (e.g. regarding hunting skills) is particularly important for ensuring animals are self-sustaining after release. We document the rehabilitation and release of three confiscated cheetah (Acinonyx jubatus) cubs and one leopard (Panthera pardus) cub, which were taken from the wild in Botswana. The animals were raised with minimal human contact and the development of their hunting skills was observed and assisted by limited pre-release training. After release, all animals were monitored and data showed they successfully hunted, with behavioural patterns similar to wild conspecifics. All established stable home ranges at the release site.Home ranges of the cheetahs ranged from 44 to 121 km2, travelling primarily during the early morning and evening, ranging from4.5 to 9.4 km/day. While the leopard survived and probably reproduced within a stable home range (449km2), all three cheetahs were shot within 7 months of release. Therefore, although orphaned large felids can successfully hunt after release using appropriate rehabilitation techniques, they face the same human–carnivore conflicts of their wild counterparts. Our study demonstrates the indispensable but commonly neglected need for post-release monitoring in wildlife rehabilitation

Leopard Panthera pardus density in southern Mozambique: evidence from spatially explicit capture-recapture in Xonghile Game Reserve

Rigorous status estimates of populations of large carnivores are necessary to inform their management and help evaluate the effectiveness of conservation interventions. The African leopard Panthera pardus faces rising anthropogenic pressures across most of its contracting sub-Saharan range, but the scarcity of reliable population estimates means that management decisions often have to rely on expert opinion rather than being based on sound evidence. This is particularly true for Mozambique, where little is known about the ecology or conservation status of leopard populations as a result of prolonged armed conflict. We used camera trapping and spatially explicit capture-recapture models to provide a leopard density estimate in Xonghile Game Reserve in southern Mozambique, which is part of the Greater Limpopo Transfrontier conservation initiative. The estimated population density was 2.60 +/- SE 0.96 leopards/100 km(2). Our study provides a baseline leopard density for the region and the first empirical density estimate for southern Mozambique. Our results also suggest that current methods used to set trophy hunting quotas for leopards, both in Mozambique and elsewhere in Africa, may be leading to unsustainable quotas, which highlights the importance of robust empirical data in guiding conservation policy

Animal welfare considerations for using large carnivores and guardian dogs as vertebrate biocontrol tools against other animals

Introducing consumptive and non-consumptive effects into food webs can have profound effects on individuals, populations and communities. This knowledge has led to the deliberate use of predation and/or fear of predation as an emerging technique for controlling wildlife. Many now advocate for the intentional use of large carnivores and livestock guardian dogs as more desirable alternatives to traditional wildlife control approaches like fencing, shooting, trapping, or poisoning. However, there has been very little consideration of the animal welfare implications of deliberately using predation as a wildlife management tool. We assess the animal welfare impacts of using dingoes, leopards and guardian dogs as biocontrol tools against wildlife in Australia and South Africa following the ‘Five Domains’ model commonly used to assess other wildlife management tools. Application of this model indicates that large carnivores and guardian dogs cause considerable lethal and non-lethal animal welfare impacts to the individual animals they are intended to control. These impacts are likely similar across different predator-prey systems, but are dependent on specific predator-prey combinations; combinations that result in short chases and quick kills will be rated as less harmful than those that result in long chases and protracted kills. Moreover, these impacts are typically rated greater than those caused by traditional wildlife control techniques. The intentional lethal and non-lethal harms caused by large carnivores and guardian dogs should not be ignored or dismissively assumed to be negligible. A greater understanding of the impacts they impose would benefit from empirical studies of the animal welfare outcomes arising from their use in different contexts

Double Umbilical Cord Blood Transplantation in High-Risk Hematological Patients: A Phase II Study Focusing on the Mechanism of Graft Predominance

Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

The Separation of 241

Electrical power sources used in outer planet missions are a key enabling technology for data acquisition and communications. State–of-the-art power sources generate electricity from alpha decay of 238Pu via thermoelectric conversion. However, production of 238Pu requires specialist facilities including a nuclear reactor, a source of 237Np for target irradiation and hotcells to chemically separate neptunium and plutonium within the irradiated targets. These specialist facilities are expensive to build and operate, so naturally, a more economical alternative is attractive to the industry. Within Europe 241Am is considered a promising alternative heat source for radioisotope thermoelectric generators (RTGs) and radioisotope heating units (RHUs). As a daughter product of 241Pu decay, 241Am exists in 1000 kgs quantities within the UK civil plutonium stockpile. A chemical separation process is required to extract the 241Am in a pure form and this paper describes the AMPPEX process (Americium and Plutonium Purification by Extraction), successfully developed over the past five years to isolate 241Am in high yield (> 99%) and to a high purity (> 99%). The process starts by dissolving plutonium dioxide in nitric acid with the aid of a silver(II) catalyst, which is generated electrochemically. The solution is then conditioned and fed to a PUREX type solvent extraction process, where the plutonium is separated from the americium and silver. The plutonium is converted back to plutonium dioxide and the americium is fed forward to a second solvent extraction step. Here the americium is selectively extracted leaving the silver in the aqueous phase. The americium is stripped from the solvent and recovered from solution as americium oxalate, which is calcined to give americium dioxide as the final product. This paper will describe the development of the separation process over a series of six solvent extraction separation trials using centrifugal contactors. The material produced (~ 4g 241Am) was used to make ceramic pellets to establish the behaviour of americium oxide material under high temperature (1450°C) sintering conditions. The chemical separation process is now demonstrated at concentrations expected on the full scale facility taking this process to TRL 4-5