Chance Of Persistence Research Articles

The delayed demographic responses of small mammals to habitat quality and density in the Brazilian Cerrado

Understanding the effects of exogenous and endogenous factors on species demographic rates is crucial to investigate their chances of persistence on natural ecosystems. We used a 9-year time series, based on monthly captures, to test the delayed effects of endogenous (density) and exogenous (rainfall, habitat cover/heterogeneity, fire) factors on the survival and recruitment rates of two small mammals inhabiting the Brazilian Cerrado: the semelparous, scansorial marsupial Gracilinanus agilis and the iteroparous, arboreal rodent Rhipidomys macrurus. As in most short-lived small mammals, we found negative density-dependent effects on the recruitment of both species (3 months delay), which could occur through reduced immigration or fecundity, in addition to the semelparous breeding strategy of G. agilis. Reduced habitat cover following fire events had a negative delayed effect on the survival of G. agilis (3 months after) and R. macrurus (1 year after), albeit it increased the recruitment rates (1-year lagged effect) of R. macrurus. We failed to find any effect of fire on demography of either species. Our results suggest that the irregular and non-cyclical fluctuations in R. macrurus abundance were driven by the interaction between delayed density dependence and changes in habitat quality, while the marked and repeated fluctuations in G. agilis abundance were mainly shaped by the occurrence of semelparity associated with direct density dependence. We emphasize that changes in habitat quality brought by human-made activities may have severe impacts on the dynamics and persistence of forest-dependent small mammals in the Cerrado.

Systemic racism alters wildlife genetic diversity

In the United States, systemic racism has had lasting effects on the structure of cities, specifically due to government-mandated redlining policies that produced racially segregated neighborhoods that persist today. However, it is not known whether varying habitat structures and natural resource availability associated with racial segregation affect the demographics and evolution of urban wildlife populations. To address this question, we repurposed and reanalyzed publicly archived nuclear genetic data from 7,698 individuals spanning 39 terrestrial vertebrate species sampled in 268 urban locations throughout the United States. We found generally consistent patterns of reduced genetic diversity and decreased connectivity in neighborhoods with fewer White residents, likely because of environmental differences across these neighborhoods. The strength of relationships between the racial composition of neighborhoods, genetic diversity, and differentiation tended to be weak relative to other factors affecting genetic diversity, possibly in part due to the recency of environmental pressures on urban wildlife populations. However, the consistency of the direction of effects across disparate taxa suggest that systemic racism alters the demography of urban wildlife populations in ways that generally limit population sizes and negatively affect their chances of persistence. Our results thus support the idea that limited capacity to support large, well-connected wildlife populations reduces access to nature and builds on existing environmental inequities shouldered by predominantly non-White neighborhoods.

Do transposable elements have functions of their very own?

Philosophers who study the problem of biological function often begin their deliberations by reflecting on the functions of parts of animals, or the behavior of animals. Applying theories of biological function to unconventional or borderline cases can help us to better evaluate and refine those theories. This is the case when we consider whether parts of transposable elements (TEs)—bits of “selfish” DNA that move about within a host genome—have functions of their own, that is, whether the parts of TEs have the function of helping the TE move about within the genome. Here I argue that whether or not the parts of TEs have functions depends crucially on whether collections of TEs form “populations,” by which I mean, here, a group of individuals of the same type that impact one another’s chances of persistence or multiplication, by impacting one another’s access to a shared resource. I think there is suggestive, but not conclusive, evidence that some TEs have functions of their own. Considering the problem of TE functionality, then, has value both for philosophy and for biology.

The effect of flight efficiency on gap‐crossing ability in Amazonian forest birds

AbstractThe ability to move across the landscape is a fundamental property of species that can determine their chances of persistence in fragmented landscapes and in rapidly changing environments. Despite its importance, empirical evidence showing the effect of movement capacity on patterns of movement across fragmented landscapes is limited. In this study, we examine the role of flight efficiency on the likelihood of crossing a man‐made habitat gap. We used data from the Biological Dynamics of Forest Fragments Projects on recaptures of banded birds in an Amazonian forest bisected by a road. For a total of 45 species, we estimated flight efficiency using the hand‐wing index (a proxy for the wing's aspect ratio) and used it as a predictor of the probability of road crossing in phylogenetic binomial regression models. We found that flight efficiency was a strong predictor of road‐crossing probability: species with high hand‐wing indices crossed the road more frequently than those with low hand‐wing indices. In contrast, other characteristics such as body mass, diet, flocking behavior, and foraging stratum did not show significant associations with road‐crossing probability. Our results suggest that proxies of flight efficiency such as the hand‐wing index can be powerful tools for predicting the vulnerability of bird species to forest fragmentation.Abstract in Spanish is available with online material

CLINICAL AND LABORATORY PREDICTORS OF PAIN SYNDROME PERSISTENCE IN ELDERLY AND SENILE PATIENTS DURING LATE POSTOPERATIVE PERIOD

Changes in neurohumoral regulation and emotional perception of nociceptive impulses in elderly and senile patients result in some clinical peculiarities of pain syndrome manifestation. Recent studies have shown that more than 10% of geriatric patients experience pain not only as an irritant but also as a psychosomatic condition. Persistence of pain in the postoperative period in the elderly and senile patients can turn into its catastrophic and chronic character in the future thus impacting the quality of life of patients and increasing the health care economic expenses to provide the proper chronic pain management. Therefore, the aim of this study is to determine the main predictors of pain persistence in the elderly and senile patients in the late postoperative period. The study included 201 male and female patients who underwent surgery regardless of surgical profile. All patients were divided into 3 groups according to age: group 1 (n = 82) included the elderly individuals, group 2 (n = 21) included senile individuals, and the control group (n = 98) included the adult patients.
 To evaluate the presence and severity of pain syndrome, pain assessment was performed by applying 100-score visual-analog scale in 1 and 7 days. A detailed study of the perception of postoperative pain was performed by the McGill questionnaire, which was used only on day 7, because on day 1 patients could be weakened after surgery, and the results distorted by the action of drugs. All examined patients were measured for fasting cortisol in the morning on the 1st and 7th day. The blood collection procedure was performed according to the general requirements for medical and biological tests. Blood was drawn from a vein by a nurse in the direct presence of a doctor. The serum cortisol content was determined using a set of reagents for quantitative enzyme-linked immunosorbent assay. The study has demonstrated that age, score on the visual-analog scale and the evaluation scale of the McGill questionnaire for day 7, as well as blood cortisol concentration in day 1 after surgery are of definite prognostic value for the risk of persistence of postoperative pain syndrome. The chance of persistence of postoperative pain increases in 1.1 times for each year in older patients, 1.3 times for each score according to the visual-analog scale for 7 days, and in 11.4 times for each score on the evaluation scale of the McGill questionnaire, and in 2.4 times for each nmol/l of cortisol concentration in 1 day after surgery. Thus, the determined risk factors for persistence of postoperative pain include the patient's age, assessment of pain by applying a visual-analog scale, and the evaluation scale by the McGill questionnaire for 7 days and the concentration of blood cortisol in 1 day after surgery.

Increasing temperature threatens an already endangered coastal dune plant

AbstractClimate change has the potential to reduce the abundance and distribution of species and threaten global biodiversity, but it is typically not listed as a threat in classifying species conservation status. This likely occurs because demonstrating climate change as a threat requires data‐intensive demographic information. Moreover, the threat from climate change is often studied in specific biomes, such as polar or arid ones. Other biomes, such as coastal ones, have received little attention, despite being currently exposed to substantial climate change effects. We forecast the effect of climate change on the demography and population size of a federally endangered coastal dune plant (Lupinus tidestromii). We use data from a 14‐yr demographic study across seven extant populations of this endangered plant. Using model selection, we found that survival and fertility measures responded negatively to temperature anomalies. We then produced forecasts based on stochastic individual‐based population models that account for uncertainty in demographic outcomes. Despite large uncertainties, we predict that all populations will decline if temperatures increase by 1°C. Considering the total number of individuals across all seven populations, the most likely outcome is a population decline of 90%. Moreover, we predict extinction is certain for one of our seven populations. These results demonstrate that climate change will profoundly decrease the current and future population growth rates of this plant, and its chance of persistence. Thus, our study provides the first evidence that climate change is an extinction threat for a plant species classified as endangered under the USA Endangered Species Act.

Adapting to the Transitional Stage of the Doctoral Environment: An Autoethnography of Socialization

Aim/Purpose: Adapting to the doctoral environment can be a difficult transition. This article emphasizes the importance of academic socialization as a means of integrating into the doctoral culture and persisting during the initial transition to doctoral study. Background: To address the problem of doctoral attrition, I share a personal narrative of problems and persistence during the first year of doctoral coursework. By sharing my initial resistance to social learning and eventual appreciation of merging the social into the academic, this narrative demonstrates the positive impact of socialization on my first year, thus promoting socialization as a means of acclimating to the doctoral environment. Methodology: This project utilizes the qualitative research method of autoethnography to examine my personal experiences adapting to the doctoral environment and connects those experiences to the larger higher education community. Contribution: Since people often connect more with stories than with numbers, my narrative offers struggling doctoral students an opportunity to see possible aspects of themselves in the lived experiences of someone who persisted, to see that they are not alone with their struggles and understand that supplementing their independent studies with social experiences could be a good way for them to persist in their own doctoral studies. Findings: Although I preferred independent work and significantly underestimated the value of social experiences when entering my first year of doctoral study, peer-to-peer interaction quickly became an essential element in my adaptation to the doctoral environment. Recommendations for Practitioners: Results of this study suggest that even when new doctoral students typically prefer solitary work, they should still seek out social learning experiences as a means of acclimating to the doctoral environment. University faculty and staff should incorporate social learning activities into the first year of their programs to promote socialization of their first-year doctoral students and increase their chances of persistence. Recommendation for Researchers: Researchers should use a variety of methods to examine the experiences of doctoral students and look at the data in new ways to better understand doctoral student needs and uncover new ideas to assist them. Impact on Society: By sharing storied experiences of struggles and success, I hope to inspire doctoral students to work with their peers and support one another as they try to persist. Future Research: More personal experiences of doctoral students are needed to give us a better understanding of the obstacles they encounter, so we can uncover additional strategies to combat those issues and improve persistence.

The Making of Relatives: Creating a home away from Home for American Indian Pre-Service Teachers at a Predominantly White Institution

Despite the many retention models in place to support American Indian/Alaska Native (AI/AN) students’ academic success within Predominantly White Institutions (PWIs) of higher learning, AI/AN student persistence and degree completion continues to be in a state of crisis. Here we highlight the factors that enhance or diminish persistence and describe culturally congruent mentoring approaches. In this article we are focusing on the extraordinary group of American Indian achievers who are members of the Society of INdigenous Educators (SINE) and who, against tremendous odds, persisted and graduated from their teacher preparation program at a land grant institution in the western United States. The SINE mentoring program was created to recruit, retain, graduate, place and provide ongoing support to these pre-service teachers. As is, the status quo at PWIs falls short at best, and in many circumstances diminishes AI/AN students’ chances for persistence and completion. By embracing the concept of creating a secondary home away from Home, where students in college have the social, and academic supports necessary, we have conceptualized and developed a culturally congruent, discipline-specific mentoring program. As key advocates, faculty mentors need a repertoire of knowledge and capacities to support novices’ induction into teaching, and to help students navigate institutional, departmental, and programmatic requirements in the university context by developing a constellation of supporters. Given only .4 % of faculty on college campuses are AI/AN, it is unlikely that AI/AN students will have an AI/AN faculty mentor in the leadership position of their culturally congruent, discipline-specific mentoring group. This being the case, we identify specific attributes that we recommend for selecting a faculty mentor to serve AI/AN students.

Predicting Persistence of Rio Grande Cutthroat Trout Populations in an Uncertain Future

AbstractThe Rio Grande Cutthroat Trout Oncorhynchus clarkii virginalis (RGCT) occupies just 12% of its ancestral range. As the southernmost subspecies of Cutthroat Trout, we expect a warming climate to bring additional stressors to RGCT populations, such as increased stream temperatures, reduced streamflows, and increased incidence of wildfire. We developed a Bayesian network (BN) model using site‐specific data, empirical research, and expert knowledge to estimate the probability of persistence for each of the 121 remaining RGCT conservation populations and to rank the severity of the threats they face. These inputs quantified the genetic risks (e.g., inbreeding risk and hybridization risk), population demographics (disease risk, habitat suitability, and survival), and probability of stochastic disturbances (stream drying risk and wildfire risk) in an uncertain future. We also created stream temperature and base flow discharge models coupled with regionally downscaled climate projections to predict future abiotic conditions at short‐term (2040s) and long‐term (2080s) time horizons. In the absence of active management, we predicted a decrease in the average probability of population persistence from 0.53 (current) to 0.31 (2040s) and 0.26 (2080s). Only 11% of these populations were predicted to have a greater than 75% chance of persisting to the 2080s. Threat of invasion by nonnative trout had the strongest effect on population persistence. Of the 78 populations that are already invaded or lacking complete barriers, 60% were estimated to be extirpated by 2080 and the remainder averaged only a 10% chance of persistence. In contrast, the effects of increased stream temperatures were predicted to affect the future persistence of only 9% of the 121 RGCT populations remaining, as most have been restricted to high‐elevation habitats that are cold enough to buffer against some stream warming. Our BN model provides a framework for evaluating threats and will be useful to guide management actions that are likely to provide the most benefit for long‐term conservation.

Identifying long-term stable refugia for relict plant species in East Asia

Today East Asia harbors many “relict” plant species whose ranges were much larger during the Paleogene-Neogene and earlier. The ecological and climatic conditions suitable for these relict species have not been identified. Here, we map the abundance and distribution patterns of relict species, showing high abundance in the humid subtropical/warm-temperate forest regions. We further use Ecological Niche Modeling to show that these patterns align with maps of climate refugia, and we predict species’ chances of persistence given the future climatic changes expected for East Asia. By 2070, potentially suitable areas with high richness of relict species will decrease, although the areas as a whole will probably expand. We identify areas in southwestern China and northern Vietnam as long-term climatically stable refugia likely to preserve ancient lineages, highlighting areas that could be prioritized for conservation of such species.

Differential persistence favors habitat preferences that determine the distribution of a reef fish

Baby reef fish have great taste when choosing a home. For most coral reef fishes, babies hatch as tiny larvae that develop offshore before returning to choose a home on the reef. Using experimental and observational approaches, we show that baby sponge-dwelling neon gobies use visual cues to choose sponge homes that will improve their chances of persistence. Ultimately, these choices result in the distribution of neon gobies on the reef.

Winter durability of pygmy bluetongue lizard burrows is higher for occupied than for unoccupied burrows and for those in less-grazed neighbourhoods

Context Many ectothermic animals survive winter by hibernating, either buried or in burrows. During their hibernation these animals are vulnerable to changes in soil structure and temperature caused by the activity of grazing mammals. This may be a particular risk to ectotherms living in native grassland, as this habitat is often used for livestock grazing. The endangered pygmy bluetongue lizard lives in burrows, in fragments of native grassland in South Australia, and these burrows are likely to be affected by sheep grazing during the lizards’ hibernation. Aims The current study aimed to determine the following effects on the persistence of burrows suitable to the pygmy bluetongue lizard: different levels of grazing, winter vegetation cover, burrow entrance size and whether a lizard was overwintering in the burrow. Methods During two winters, we applied different grazing treatments to six experimental paddocks and determined whether suitable lizard burrows located in autumn were still suitable to lizards in the following spring. For each burrow, we recorded whether a lizard was overwintering, the burrow entrance diameter and the vegetation cover around the burrow during the winter. Key results Increased grazing pressure led to decreased persistence of lizard burrows. We also found that burrows with an overwintering lizard had a greater chance of persisting, but found no direct effect of winter vegetation cover or entrance diameter. Conclusions The results show that although pygmy bluetongue lizards may be able to stabilise their own burrows, the more intense the grazing the lower the chance of lizard burrow persistence. Implications Management of sheep grazing is an important component in future conservation of the endangered pygmy bluetongue lizard. Grazing on grassland with a lizard population should be kept at a moderate level and hard grazing should be avoided.

Patterns in species persistence and biomass production in soil microcosms recovering from a disturbance reject a neutral hypothesis for bacterial community assembly.

The neutral theory of biodiversity has emerged as a major null hypothesis in community ecology. The neutral theory may sufficiently well explain the structuring of microbial communities as the extremely high microbial diversity has led to an expectation of high ecological equivalence among species. To address this possibility, we worked with microcosms of two soils; the microcosms were either exposed, or not, to a dilution disturbance which reduces community sizes and removes some very rare species. After incubation for recovery, changes in bacterial species composition in microcosms compared with the source soils were assessed by pyrosequencing of bacterial 16S rRNA genes. Our assays could detect species with a proportional abundance ≥ 0.0001 in each community, and changes in the abundances of these species should have occurred during the recovery growth, but not be caused by the disturbance per se. The undisturbed microcosms showed slight changes in bacterial species diversity and composition, with a small number of initially low-abundance species going extinct. In microcosms recovering from the disturbance, however, species diversity decreased dramatically (by > 50%); and in most cases there was not a positive relationship between species initial abundance and their chance of persistence. Furthermore, a positive relationship between species richness and community biomass was observed in microcosms of one soil, but not in those of the other soil. The results are not consistent with a neutral hypothesis that predicts a positive abundance-persistence relationship and a null effect of diversity on ecosystem functioning. Adaptation mechanisms, in particular those associated with species interactions including facilitation and predation, may provide better explanations.

Food abundance, kittiwake life histories, and colony dynamics in the Northeastern Pacific: implications of climate change and regime shifts

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 515:251-263 (2014) - DOI: https://doi.org/10.3354/meps10994 Food abundance, kittiwake life histories, and colony dynamics in the Northeastern Pacific: implications of climate change and regime shifts Simone Vincenzi1,2,*, Marc Mangel2,3 1Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Via Ponzio 34/5, 20133 Milan, Italy 2Center for Stock Assessment Research and Department of Applied Mathematics and Statistics, University of California, Santa Cruz, CA 95064, USA 3Department of Biology, University of Bergen, PO Box 7803, 5020 Bergen, Norway *Corresponding author: simon.vincenz@gmail.com ABSTRACT: Black-legged kittiwakes Rissa tridactyla in the Northeastern Pacific will increasingly experience climate-induced changes in the variability of forage fish, which will influence both the quantity and quality of food and may thus alter the population dynamics of kittiwake colonies. However, the relative roles of individual- and population-level traits in determining colony dynamics and risk of extinction are still unclear. We combined models of components of the Pacific kittiwake life history with empirical data linking physiological stress and food abundance to provide a unified treatment of kittiwake colony dynamics. We simulated the dynamics of colonies with high, medium and low responsiveness of productivity to variation in nutritional stress in breeding birds, using data from Alaskan colonies. We found that the risk of quasi-extinction strongly decreased with a moderate increase in the potential number of yearly immigrants. Pre-breeding mortality as a function of growth during development had only a marginal role in determining median number of breeding pairs over simulation time. We predict that temporal autocorrelation of colony-wide average productivity and high nutritional stress, particularly if consistent over time, will increase quasi-extinction risk. Our work shows that colonies with low productivity have little chance of persistence even when survival of pre-breeding and breeding birds is high, and that the nature of the temporal auto-correlation of food conditions and productivity is crucial to understand the effect of environmental fluctuations, regime shifts, and climate change on population dynamics of kittiwakes. We use the model to highlight the most valuable future empirical studies. KEY WORDS: Black-legged kittiwakes · Food abundance · Corticosterone · Immigration · Temporal auto-correlation Full text in pdf format PreviousNextCite this article as: Vincenzi S, Mangel M (2014) Food abundance, kittiwake life histories, and colony dynamics in the Northeastern Pacific: implications of climate change and regime shifts. Mar Ecol Prog Ser 515:251-263. https://doi.org/10.3354/meps10994 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 515. Online publication date: November 18, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Host specificity of a bird-specialised endophilic ectoparasite, the tree-hole tick Ixodes arboricola.

Host specialisation in parasites can be due to either limited exposure or limited adaptation to different host types. When the first barrier is lifted experimentally, the degree of adaptive specialisation can be studied. The tree-hole tick Ixodes arboricola is an endophilic parasite with a narrow host range, found in nest boxes used mainly by great and blue tits (Parus major, Cyanistes caeruleus) and to a lesser extent by pied flycatchers (Ficedula hypoleuca) and nuthatches (Sitta europaea). In the current study, we exposed two nestlings per nestbox of pied flycatchers (N = 14), blue tits (N = 18), great tits (N = 14), and nuthatches (N = 16) to ten I. arboricola nymphs each. We found no differences in attachment success 2 days after infestation (56 ± 4% across species) nor were there any differences in tick engorgement weight (1.95 ± 0.03 mg across species), and moulting success was >90% for ticks from all bird species. Hence, our data suggest that all bird species investigated here are suitable host species. This may enhance the ticks' chances for persistence in cavities and dispersal among cavities inhabited by multiple host species, and supports the hypothesis that host use by ticks is limited by host ecology rather than by host specialisation.

An International Crime Decline: Lessons for Social Welfare Crime Policy?

AbstractDuring the past two decades, crime rates have declined in Europe and North America. A number of explanations have been offered for why this has come about, but there has been much less discussion about what governments should do now. This article considers the policy implications of an international crime decline with a focus on the relationship between crime reduction and social welfare. The discussion here includes the possibility of a convergence across social welfare improvements, the danger of misreading the USA as a trend‐setter, the potential of the Scandinavian way in situational crime prevention, the chance of persistence in high‐crime politics and the dilemma of realizing social policy objectives from crime reduction initiatives.

State Financial Policies and College Student Persistence: A National Study

In the context of the privatization of higher education, this study examines the possible role of state finances in promoting equal educational opportunities. Through the combined use of a national representative database and a state finance database and the application of hierarchical generalized linear modeling methods, this study found that state funding of need-based aid was positively associated with college students' chances of persistence, while findings regarding state funding on non-need-based aid are mixed and merit further research.

Variation in stage structure and fitness traits between road verge and meadow populations of Colchicum autumnale (Liliaceae): Effects of habitat quality

The frequency distribution and density of three life stages as well as fitness components of the perennial plant <em>Colchicum autumnale</em> growing in the unmanaged road verges and in the extensive mown and grazed meadows in the Sudeten Mts. were studied. Furthermore, investigated were the effects of population size and plant size (measured as number of flowers) on reproductive success and explored if variation in reproductive and vegetative traits of adults could be associated with soil characteristics. The t-test indicated that proportions of subadults and reproductive adults were significantly lower in verge than in meadow populations, and of vegetative adults significantly higher. The plant density of reproductive adults and the reproductive adults to all adults ratio were significantly lower in verge populations compared to meadow populations. Although habitat type accounted for significant variation in stage structure, no significant difference was found between vegetative and reproductive traits in adult plants, except for the number of flowers. In verge populations the number of flowers was significantly lower as compared to meadow populations. The traits related to reproduction were not significantly influenced by population size. However, the proportion of flowers setting fruit decreased significantly with increasing number of flowers. The stepwise multiple regression revealed significant relationships between soil characteristics and number of fruits per plant, fruit set, number seeds per plant and number of leaves in vegetative adults. The results suggest that the creation of the low and relatively open vegetation cover could increase the chance of persistence of <em>C. autumnale</em> living in verge habitats by promoting of seed germination, seedling establishment and flowering, and they also show that the reproductive success and vegetative components of fitness are most likely influenced by habitat quality.

Heading for greener pastures? Defining the foraging preferences of urban long-nosed bandicoots

The impact of urbanisation is delayed for many species, as populations that manage to survive the initial loss of habitat gradually decline throughout the urban–bushland mosaic. Yet many species’ chances of persistence within urban areas can be increased through relatively simple management techniques, and an understanding of how remnant populations use the interface between urban and natural landscapes is therefore crucial to their long-term management. Here we examine the habitat preferences of a semi-urban population of long-nosed bandicoots (Perameles nasuta) that inhabits a matrix of urban open lawn and dense native heath macrohabitats. We radio-tracked animals in these two distinct macrohabitats and compared the microhabitat features between core and peripheral areas of home ranges. Core and peripheral areas did not differ in their characteristics for either macrohabitat; however, individuals showed a high level of fidelity to distinct foraging patches. We then related microhabitat features to an index of foraging activity using generalised linear modelling and found that diggings were more abundant in areas with moist, soft soils close to cover. Soil softness and moisture were experimentally increased via artificial watering on selected sites. After only 10 days there were significantly more diggings on watered than non-watered sites. Thus, bandicoots appear to be a matrix-sensitive species, using some open grass areas of the matrix but requiring the vegetation cover of remnant bush. We suggest, however, that artificial watering and additional cover may be one way to increase foraging opportunities to make this, and other semi-urban, populations matrix-occupying, and thus facilitate bandicoot persistence in the urban mosaic.

Dogs on the catwalk: Modelling re-introduction and translocation of endangered wild dogs in South Africa

In South Africa, a plan was launched to manage separate sub-populations of endangered African wild dogs ( Lycaon pictus) in several small, geographically isolated conservation areas as a single meta-population. This intensive management approach involves the re-introduction of wild dogs into suitable conservation areas and periodic translocations among them. Despite the initial failures and high costs associated with wild dog re-introductions and translocations, there is no predictive framework available to quantify which management protocol is the most efficient. We therefore developed an individual-based model of wild dog population and pack dynamics, which accounts for the wild dogs’ social complexity. The model appeared to capture the essential characteristics of a real wild dog population from Hluhluwe-iMfolozi Park, South Africa and to be relatively robust to parameter uncertainty, suggesting that the model is valid enough for addressing management problems. The model enabled us to quantify a critical initial number of packs (two) and individuals per pack (six) necessary for a re-introduced wild dog population to establish itself in the release area. We also found a practically feasible intervention regime at which a re-introduced wild dog population had the best chance of persistence: intermittently adding packs (at least every 6 years) and harvesting disperser groups (as often as every 4 years) for translocation to other release sites, without threatening the small source population. This study demonstrates that individual-based models can be a powerful decision-support tool in re-introduction planning and provides insight into how populations made up of social groups have dynamics, and ultimately persistence, determined by individual behaviour.