Modeling Trap-Awareness and Related Phenomena in Capture-Recapture Studies

Trap-awareness and related phenomena whereby successive capture events are not independent is a feature of the majority of capture-recapture studies. This phenomenon was up to now difficult to incorporate in open population models and most authors have chosen to neglect it although this may have damaging consequences. Focusing on the situation where animals exhibit a trap response at the occasion immediately following one where they have been trapped but revert to their original naïve state if they are missed once, we show that trap-dependence is more naturally viewed as a state transition and is amenable to the current models of capture-recapture. This approach has the potential to accommodate lasting or progressively waning trap effects

Should rehabilitated hedgehogs be released in winter? A comparison of survival, nest use and weight change in wild and rescued animals

The rehabilitation of sick or injured wildlife and their subsequent release back into the wild is considered important, not only for the welfare of the individual animal but also for the conservation and management of endangered and threatened wildlife. The European hedgehog Erinaceus europaeus has declined by 25% in Britain over the last decade and is the most common mammal admitted to wildlife rehabilitation centres in Britain, with a large proportion of individuals admitted to gain body weight overwinter prior to release in the spring. Consequently, many thousands of hedgehogs are housed overwinter which incurs significant costs for rehabilitation centres, and has potentially animal welfare issues, such as, stress in captivity, reintroduction stress, increased mortality risk and impaired or altered behaviour. To determine if releasing rehabilitated hedgehogs during autumn and winter had an effect on their survival, body weight or nesting behaviour, we compared these factors between 34 rehabilitated hedgehogs with 23 wild hedgehogs across five sites in England over four different winters. Overwinter survival was high for both wild and rehabilitated hedgehogs, with a significant decrease in survival across both groups when hedgehogs became active post hibernation in spring. We found no differences in the survival rates up to 150 days post release, in weight change, or nest use between wild- and winter-released rehabilitated hedgehogs. Our results suggest that under the correct conditions, rehabilitated hedgehogs can be released successfully during winter, therefore avoiding or reducing time in captivity

Similar Prevalence of Plasmodium falciparum and Non–P. falciparum Malaria Infections among Schoolchildren, Tanzania

Achieving malaria elimination requires considering both Plasmodium falciparum and non–P. falciparum infections. We determined prevalence and geographic distribution of 4 Plasmodium spp. by performing PCR on dried blood spots collected within 8 regions of Tanzania during 2017. Among 3,456 schoolchildren, 22% had P. falciparum, 24% had P. ovale spp., 4% had P. malariae, and 0.3% had P. vivax infections. Most (91%) schoolchildren with P. ovale infections had low parasite densities; 64% of P. ovale infections were single-species infections, and 35% of those were detected in low malaria endemic regions. P. malariae infections were predominantly (73%) co-infections with P. falciparum. P. vivax was detected mostly in northern and eastern regions. Co-infections with >1 non–P. falciparum species occurred in 43% of P. falciparum infections. A high prevalence of P. ovale infections exists among schoolchildren in Tanzania, underscoring the need for detection and treatment strategies that target non–P. falciparum species

Use of Integrated Modeling to Enhance Estimates of Population Dynamics Obtained from Limited Data

International audienceDemographic data of rare and endangered species are often too sparse to estimate vital rates with sufficient precision for understanding population growth and decline. Yet, the combination of different sources of demographic data into one statistical model holds promise. We applied Bayesian integrated population modeling to demographic data from a colony of the endangered greater horseshoe bats (Rhinolophus ferrumequinum). Available data were the number of subadults and adults emerging from the colony roost at dusk, the number newborns from 1991 to 2005, as well as recapture data of subadults and adults from 2004 and 2005. Survival rates did not differ between sexes and demographic rates remained constant across time. The greater horseshoe bat is a long-lived species with high survival rates (first year: 0.49 [SD: 0.06], adults: 0.91 [SD: 0.02]) and low fecundity (0.74 [SD: 0.12]). The yearly average population growth was 4.4%. Had we analyzed each data set separately, we would not have been able to estimate fecundity, the estimates of survival would have been less precise and the estimate of population growth biased. Our results demonstrate that integrated models are suitable for obtaining crucial demographic information from limited data