Developing a methodology for the National Frog Survey of Ireland: a pilot study in Co. Mayo.

A National Frog Survey of Ireland is planned for spring 2011. We conducted a pilot survey of 25 water bodies in ten 0.25 km2 survey squares in Co. Mayo during spring 2010. Drainage ditches were the most commonly available site for breeding and, generally, two 100 m stretches of ditch were surveyed in each square. The restricted period for peak spawning activity renders any methodology utilizing only one site visit inherently risky. Consequently, each site was visited three times from late March to early April. Occurrence of spawn declined significantly from 72 % to 44 % between the first and third visit whilst the overall occurrence of spawn at all sites was 76 %. As the breeding season advanced, spawn either hatched or was predated and, therefore, disappeared. In those water bodies where spawning was late, however, greater densities of spawn were deposited than in those sites where breeding was early. Consequently, spawn density and estimated frog density did not differ significantly between site visits. Future surveys should nevertheless include multiple site visits to avoid biased estimation of species occurrence and distribution. Ecological succession was identified as the main threat present at 44 % of sites.

Mammals and agri-environment schemes: hare haven or pest paradise?

1. Agri-environment schemes (AESs) are designed to create landscape-scale improvements in biodiversity. While the specific aims of AESs do not always include the enhancement of species of conservation concern, associated conservation strategies, such as the UK Biodiversity Action Plan, often rest on the assumption that AESs enhance environmental conditions and thereby improve the conservation status of target species. However, there is little evidence for the general efficacy of AESs in this respect. 2. To evaluate the effects of the Environmentally Sensitive Area (ESA) scheme, a widespread AES in Northern Ireland, a spotlight survey of the relative abundance of three mammal species, Irish hare Lepus timidus hibernicus, European rabbit Oryctolagus cuniculus and red fox Vulpes vulpes, was conducted. Of these, the Irish hare is a priority species for conservation action and the focus of a species action plan, while rabbit and fox are commonly considered agricultural pests. The effects of ESA designation and habitat on each species were assessed at 150 ESA and 50 non-ESA sites, matched for landscape characteristics. 3. The ESA scheme had no demonstrable effect on the abundance of Irish hares, and this agri-environment scheme did not target the landscape and habitat variables associated with hares. 4. In contrast, the abundance of rabbits and foxes was significantly greater within ESAs than the wider countryside. Agricultural factors such as reduced livestock stocking density, reduced overgrazing and field boundary enhancements may create more favourable conditions for both species. Aside from the implications for farm economics, the proliferation of rabbit populations within conservation areas may raise issues concerning the grazing of important plant communities, while increases in fox populations may adversely affect ground-nesting birds and other animal species of conservation concern. 5. Synthesis and applications: The abundance of rabbits and foxes corroborates recent work that suggests AESs may benefit common species but can not be relied upon to encourage rarer species. The Irish hare species action plan relies on agri-environment schemes to enhance the species’ status and realize the target of increasing the hare population by 2010 by promoting suitable habitat. However, the ESA scheme is unlikely to help in achieving these objectives. Targeted and evidence-based agri-environment prescriptions are clearly required in order to ensure the realization of species-specific conservation targets.

The pitfall with PIT tags: Marking freshwater bivalves for translocation induces short-term behavioural costs

Tagging animals is frequently employed in ecological studies to monitor individual behaviour, for example postrelease survival and dispersal of captive-bred animals used in conservation programmes. While the majority of studies focus on the efficacy of tags in facilitating the relocation and identification of individuals, few assess the direct effects of tagging in biasing animal behaviour. We used an experimental approach with a control to differentiate the effects of handling and tagging captive-bred juvenile freshwater pearl mussels, Margaritifera margaritifera, prior to release into the wild. Marking individuals with passive integrated transponder (PIT) tags significantly decreased their burrowing rate and, therefore, increased the time taken to burrow into the substrate. This effect was contributed to, in part, by the detrimental impacts of handling, which also significantly affected activity, burrowing ability and the time taken for each individual to emerge and start probing the substrate. Disturbance during handling and tagging may lead to indirect mortality after release by increasing the risk of predation or dislodgement during flooding, thereby potentially compromising any conservation strategy contingent on population supplementation or reintroduction. This is the first study to demonstrate that handling and PIT tagging has a detrimental impact on invertebrate behaviour. Moreover, our results provide useful information that will inform freshwater bivalve conservation strategies.

Applying species distribution modelling to identify areas of high conservation value for endangered species: A case study using Margaritifera margaritifera (L.)

The development and implementation of a population supplementation and restoration plan for any endangered species should involve an understanding of the species’ habitat requirements prior to the release of any captive bred individuals. The freshwater pearl mussel, Margaritifera margaritifera, has undergone dramatic declines over the last century and is now globally endangered. In Northern Ireland, the release of captive bred individuals is being used to support wild populations and repatriate the species in areas where it once existed. We employed a combination of maximum entropy modelling (MAXENT) and Generalized Linear Mixed Models (GLMM) to identify ecological parameters necessary to support wild populations using GIS-based landscape scale and ground-truthed habitat scale environmental parameters. The GIS-based landscape scale model suggested that mussel occurrence was associated with altitude and soil characteristics including the carbon, clay, sand, and silt content. Notably, mussels were associated with a relatively narrow band of variance indicating that M. margaritifera has a highly specific landscape niche. The ground-truthed habitat scale model suggested that mussel occurrence was associated with stable consolidated substrates, the extent of bankside trees, presence of indicative macrophyte species and fast flowing water. We propose a three phase conservation strategy for M. margaritifera identifying suitable areas within rivers that (i) have a high conservation value yet needing habitat restoration at a local level, (ii) sites for population supplementation of existing populations and (iii) sites for species reintroduction to rivers where the mussel historically occurred but is now locally extinct. A combined analytical approach including GIS-based landscape scale and ground-truthed habitat scale models provides a robust method by which suitable release sites can be identified for the population supplementation and restoration of an endangered species. Our results will be highly influential in the future management of M. margaritifera in Northern Ireland.

Culture phenotypes of genomically and geographically diverse Mycobacterium avium subsp. paratuberculosis isolates from different hosts

Mycobacterium avium subsp. paratuberculosis causes paratuberculosis (Johne's disease) in ruminants in most countries. Historical data suggest substantial differences in culturability of M. avium subsp. paratuberculosis isolates from small ruminants and cattle; however, a systematic comparison of culture media and isolates from different countries and hosts has not been undertaken. Here, 35 field isolates from the United States, Spain, Northern Ireland, and Australia were propagated in Bactec 12B medium and Middlebrook 7H10 agar, genomically characterized, and subcultured to Lowenstein-Jensen (LJ), Herrold's egg yolk (HEY), modified Middlebrook 7H10, Middlebrook 7H11, and Watson-Reid (WR) agars, all with and without mycobactin J and some with sodium pyruvate. Fourteen genotypes of M. avium subsp. paratuberculosis were represented as determined by BstEII IS900 and IS1311 restriction fragment length polymorphism analysis. There was no correlation between genotype and overall culturability, although most S strains tended to grow poorly on HEY agar. Pyruvate was inhibitory to some isolates. All strains grew on modified Middlebrook 7H10 agar but more slowly and less prolifically on LJ agar. Mycobactin J was required for growth on all media except 7H11 agar, but growth was improved by the addition of mycobactin J to 7H11 agar. WR agar supported the growth of few isolates. The differences in growth of M. avium subsp. paratuberculosis that have historically been reported in diverse settings have been strongly influenced by the type of culture medium used. When an optimal culture medium, such as modified Middlebrook 7H10 agar, is used, very little difference between the growth phenotypes of diverse strains of M. avium subsp. paratuberculosis was observed. This optimal medium is recommended to remove bias in the isolation and cultivation of M. avium subsp. paratuberculosis.

Quantifying forage specialisation in polyphagic insects: the polylectic and rare solitary bee, Colletes floralis (Hymenoptera: Colletidae)

Many insect species vary in their degree of foraging specialisation, with many bee species considered polyphagic (polylectic). Wild, non-managed bee species vary in their conservation status, and species-specific biological traits such as foraging specialisation may play an important role in determining variance in population declines. Current agri-environment schemes (AESs) prescribe the introduction of flower seed mixes for agricultural systems to aid the conservation of wild bees. However, the extent to which flower combinations adequately meet bee foraging requirements is poorly known. We quantitatively assessed pollen use and selectivity using two statistical approaches: Bailey's Intervals and Compositional Analysis, in an examplar species, a purportedly polylectic and rare bee, Colletes floralis, across 7 sites through detailed analysis of bee scopal pollen loads and flower abundance. Both approaches provided good congruence, but Compositional Analysis was more robust to small sample sizes. We advocate its use for the quantitative determination of foraging behaviour and dietary preference. Although C. floralis is polylectic, it showed a clear dietary preference for plants within the family Apiaceae. Where Apiaceae was uncommon, the species exploited alternative resources. Other plant families, such as the Apiaceae, could be included, or have their proportion increased in AES seed mixes, to aid the management of C. floralis and potentially other wild solitary bees of conservation concern. © 2011 The Authors. Insect Conservation and Diversity © 2011 The Royal Entomological Society.

Changes in the prevalence of badger persecution in Northern Ireland.

Animal populations generally increase after release from hunting pressure and/or cessation of illegal persecution. Implementation of full legislative protection of the Eurasian badger Meles meles in Great Britain is thought to have led to increases in badger abundance due to reduced levels of persecution. Conversely, prevalence of badger persecution in Northern Ireland was historically much higher than in Great Britain, and badger abundance remained stable over time despite similar legislative protection. We examined temporal changes in the prevalence of badger sett disturbance in Northern Ireland from 1990/1993 to 2007/2008 in relation to population status. A total of 56 (12.6%) of 445 setts surveyed during 1990/1993 had been disturbed compared to 29 (4.4%) of 653 setts during 2007/2008. This was a significant decline (-65%) in the incidence of sett disturbance over the 14–18-year period. Most notably, the incidence of digging at badger setts, indicative of local badger baiting activity, declined from 50% to 3.5% of disturbed setts. Signs of recent disturbance were significantly more frequent at disused setts suggesting that once disturbed, badgers may vacate a sett. The number of badger social groups in Northern Ireland did not differ between the two study periods, suggesting that previously high levels of badger persecution did not limit the number of badger social groups. The stability of the badger population in Northern Ireland compared to the growing population in Great Britain cannot be attributed to changes in the prevalence of persecution. Differences in the trajectories of both populations could be due to a range of factors including climate, habitat composition and structure, farming practices or food availability. More work is needed to determine how such factors influence badger population dynamics.