Boscombe, United Kingdom
Boscombe, United Kingdom

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Reid N.,Queen's University of Belfast | Dingerkus S.K.,Bohola Co. | Stone R.E.,Bohola Co. | Pietravalle S.,UK Environment Agency | And 5 more authors.
Animal Conservation | Year: 2013

Global amphibian declines are a major element of the current biodiversity crisis. Monitoring changes in the distribution and abundance of target species is a basic component in conservation decision making and requires robust and repeatable sampling. For EU member states, surveillance of designated species, including the common frog Rana temporaria, is a formal requirement of the 'EC Habitats & Species Directive'. We deployed established methods for estimating frog population density at local water bodies and extrapolated these to the national and ecoregion scale. Spawn occurred at 49.4% of water bodies and 70.1% of independent 500-m survey squares. Using spawn mat area, we estimated the number of adult breeding females and subsequently the total population assuming a sex ratio of 1:1. A negative binomial model suggested that mean frog density was 23.5 frogsha-1 [95% confidence interval (CI) 14.9-44.0] equating to 196M frogs (95%CI 124M-367M) throughout Ireland. A total of 86% of frogs bred in drainage ditches, which were a notably common feature of the landscape. The recorded distribution of the species did not change significantly between the last Article 17 reporting period (1993-2006) and the current period (2007-2011) throughout the Republic of Ireland. Recording effort was markedly lower in Northern Ireland, which led to an apparent decline in the recorded distribution. We highlight the need to coordinate biological surveys between adjacent political jurisdictions that share a common ecoregion to avoid apparent disparities in the quality of distributional information. Power analysis suggested that a reduced sample of 40-50 survey squares is sufficient to detect a 30% decline (consistent with the International Union for Conservation of Nature Category of 'Vulnerable') at 80% power providing guidance for minimizing future survey effort. Our results provide a test case for other EU member states to follow when conducting future conservation assessments for R.temporaria and other clump-spawning amphibians. © 2013 The Zoological Society of London.

Beebee T.,Amphibian and Reptile Conservation | Beebee T.,University of Sussex
Herpetological Bulletin | Year: 2012

Common toads Bufo bufo have declined over much of southern and eastern England in recent decades where other widespread amphibian species have remained relatively stable. One such toad decline, at Offham marshes in Sussex, was investigated over the fifteen year period 1998-2012 immediately subsequent to a tenfold decrease in population size between 1989 and 1997. Syntopic amphibians (Rana temporaria, Lissotriton vulgaris and L. helveticus) probably also declined at this site. The surviving toad population continued to recruit new cohorts and had an apparently healthy age structure. Habitat quality (aquatic and terrestrial) remained good and there was no evidence of disease. An invasive species (Pelophylax ridibundus) was excluded as a likely cause of toad decline. However, traffic on a neighbouring road rendered more than half the previously available terrestrial habitat for toads essentially unreachable. Furthermore, reduced management of vegetation in ditches where the toads breed apparently increased mortality of developing tadpoles. Future prospects for conserving and increasing the toad population are discussed.

Biggs J.,Freshwater Habitats Trust | Ewald N.,Freshwater Habitats Trust | Valentini A.,Spygen | Gaboriaud C.,Spygen | And 8 more authors.
Biological Conservation | Year: 2014

The use of environmental DNA (eDNA) is rapidly emerging as a potentially valuable survey technique for rare or hard to survey freshwater organisms. For the great crested newt (Triturus cristatus) in the UK, the substantial cost and manpower requirements of traditional survey methods have hampered attempts to assess the status of the species. We tested whether eDNA could provide the basis for a national citizen science-based monitoring programme for great crested newts by (i) comparing the effectiveness of eDNA monitoring with torch counts, bottle trapping and egg searches and (ii) assessing the ability of volunteers to collect eDNA samples throughout the newt's UK range. In 35 ponds visited four times through the breeding season, eDNA detected newts on 139 out of 140 visits, a 99.3% detection rate. Bottle traps, torch counts and egg searches were significantly less effective, detecting newts 76%, 75% and 44% of the time. eDNA was less successful at predicting newt abundance being positively, but weakly, correlated with counts of the number of newts. Volunteers successfully collected eDNA samples across the UK with 219 of 239 sites (91.3%) correctly identified as supporting newts. 8.7% of sites generated false negatives, either because of very small newt populations or practical difficulties in sample collection. There were no false positives. Overall, we conclude that eDNA is a highly effective survey method and could be used as the basis for a national great crested newt monitoring programme. © 2014 Elsevier Ltd.

Buckley J.,Amphibian and Reptile Conservation | Beebee T.J.C.,Amphibian and Reptile Conservation | Schmidt B.R.,University of Zürich
Animal Conservation | Year: 2014

Amphibian declines around the world are a major conservation concern. Monitoring trends in abundance is therefore important. Exemplar models are required, with robust, easily assessed indicators of population size that have high and consistent detection probability and which can be quantified over large geographical scales. Natterjack toads Bufo calamita potentially fulfil these criteria. This amphibian is rare and increasingly endangered in the north European part of its range, including Britain. In this paper, we analyse data on population size (based on spawn string counts) and breeding success (toadlet production) collected over 20 years from all remaining natterjack sites in the UK, permitting for the first time an assessment of population trends of an endangered amphibian at the national scale. State-space models, which account for observation error, were developed to estimate population trends and to assesss the effects of conservation management. Between 1990 and 2009, the British population of B.calamita was approximately stable as judged by spawn string counts and broadly confirmed by state-space modelling, although this indicated that continuing small decline was more probable than stability. Empirical and model analyses also demonstrated that population growth rate was influenced positively by frequency of breeding success (toadlet production) and by grazing of the terrestrial habitat by domestic livestock. The implications of these findings for future conservation management of B.calamita are discussed. © 2013 The Zoological Society of London.

Beebee T.J.C.,Amphibian and Reptile Conservation
Journal of Herpetology | Year: 2014

Agricultural intensification, starting during the Second World War, precipitated declines in all seven native species of amphibians in Britain. Problems in the United Kingdom (U.K.) therefore predated recognition of global amphibian declines and were due to relatively simple causes, notably habitat modification and destruction. Pesticides, acid rain, ultraviolet radiation, climate change, and disease have thus far proved relatively minor issues. Amphibian conservation started in the 1970s, initially with status surveys, but by the 1980s research into habitat requirements and proactive management was underway, particularly for the rare Bufo calamita (Natterjack Toad). The relatively widespread Triturus cristatus (Great Crested Newt) was given the same legal protection as B. calamita in 1981 due largely to declines elsewhere in Europe. This protection has become problematic for conservationists on account of the many sites with this newt that regularly come under threat from development. Additional difficulties identified in the 1990s included serious impacts of road mortality on Bufo bufo (Common Toad) and inbreeding in urban populations of this species and of Rana temporaria (Common Frog). A previously unrecognized rare native, the "northern clade" of Pelophylax (formerly Rana) lessonae (Northern Pool Frog) became extinct in the early 1990s but was reintroduced in the 2000s. In the past 4 decades conservation efforts have stabilized, although not increased, the U.K B. calamita population, but some of the widespread species are still declining, albeit at a slower rate than in the postwar period. Effective methods for amphibian conservation are now available and the outstanding question is whether there will be sufficient funding to make greater gains in future. Copyright 2014 Society for the Study of Amphibians and Reptiles.

Beebee T.J.C.,Amphibian and Reptile Conservation
Journal of Zoology | Year: 2011

Severe recent declines of amphibians around the world have highlighted the need to identify factors that affect their population dynamics and viability. This study used a long-term (>30years) dataset collected for a British population of natterjack toads Bufo calamita, a rare and endangered species in much of northern Europe. Modelling was employed to test a series of hypotheses concerning the effects of anthropogenic (conservation management) and climatic factors on toad demographics. The best models accounted for >72% of the variance in population size, as judged by spawn string counts, between 1975 and 2007. Conservation management (pond creation) was important, as were spring and summer climate variables relating to larval survival, and winter conditions associated with hibernation mortality. The implications of trends associated with future climate change are also considered. © 2011 The Authors. Journal of Zoology © 2011 The Zoological Society of London.

Beebee T.,Amphibian and Reptile Conservation
Herpetological Bulletin | Year: 2012

Many species of amphibians have bred in a Woodingdean garden pond for more than 30 years. In summer 2007 an outbreak of Ranavirus occurred and this paper describes its impact on three species of anurans living wild in the garden and two species kept in an outdoor vivarium. Common frog Rana temporaria numbers were reduced by >80%. Common toads Bufo bufo decreased by perhaps 20% whereas pool frogs Pelophylax lessonae were scarcely affected. A single natterjack B. calamita died in the vivarium where at least five survived, but all midwife toads Alytes obstetricans (adults and larvae) in the same enclosure perished. There was no sign of recovery of the common frog population over the ensuing five years.

Smith R.K.,University of Cambridge | Dicks L.V.,University of Cambridge | Mitchell R.,Amphibian and Reptile Conservation | Sutherland W.J.,University of Cambridge
Conservation Evidence | Year: 2014

This editorial highlights the deficit of studies that directly compare different conservation interventions for the same threat. Most studies test a single intervention (86% in Conservation Evidence), comparing it against a control that lacks the intervention. Such studies can provide evidence that a particular intervention is effective, but do not inform a practitioner whether that intervention is the best option relative to others. Comparing results from different studies is difficult, as outcomes depend on factors such as the site, species and method of measurement. We suggest that a key step to understanding the effectiveness of conservation interventions is to compare different interventions in the same context within studies. If widely adopted this could transform global conservation practice. We provide some guidance on how to design and conduct comparative studies.

Beebee T.J.C.,Amphibian and Reptile Conservation | Buckley J.,Amphibian and Reptile Conservation
Herpetological Journal | Year: 2014

Counting cumulative numbers of spawn strings deposited by female natterjack toads Bufo calamita is widely used in Britain as a surrogate estimator of trends in population size. We analysed long-term data from 20 of the best recorded British natterjack populations to assess the relationship between spawn count and population dynamics. Spawn count, toadlet production and numbers of ponds producing toadlets were all correlated. However, high spawn deposition was more likely the cause of high toadlet production than a converse mechanism in which high toadlet production might subsequently increase adult population size. Good toadlet years did not generally correlate with spawn deposition three years later, the expected delay for cohort maturation. Conversely, new ponds could trigger large increases in spawn deposition within a year of their construction. This situation presumably arose because only a fraction of the available adult females usually breed in any one year. We conclude that although spawn string counts and actual female population size were not demonstrably synonymous, spawn counts probably do reflect relative sizes between populations and temporal trends within them except when numbers of productive ponds also change significantly over short timescales. Individual ponds can remain productive of toadlets for at least 25 years provided the habitat is managed appropriately.

Beebee T.J.C.,Amphibian and Reptile Conservation
Conservation Biology | Year: 2013

Road mortality is a widely recognized but rarely quantified threat to the viability of amphibian populations. The global extent of the problem is substantial and factors affecting the number of animals killed on highways include life-history traits and landscape features. Secondary effects include genetic isolation due to roads acting as barriers to migration. Long-term effects of roads on population dynamics are often severe and mitigation methods include volunteer rescues and under-road tunnels. Despite the development of methods that reduce road kill in specific locations, especially under-road tunnels and culverts, there is scant evidence that such measures will protect populations over the long term. There also seems little likelihood that funding will be forthcoming to ameliorate the problem at the scale necessary to prevent further population declines. © 2013 Society for Conservation Biology.

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