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Fordingbridge, United Kingdom

Wood T.J.,University of Sussex | Holland J.M.,The Game and Wildlife Conservation Trust | Goulson D.,University of Sussex
Oecologia | Year: 2015

Agri-environment schemes have been implemented across the European Union in order to reverse declines in farmland biodiversity. To assess the impact of these schemes for bumblebees, accurate measures of their populations are required. Here, we compared bumblebee population estimates on 16 farms using three commonly used techniques: standardised line transects, coloured pan traps and molecular estimates of nest abundance. There was no significant correlation between the estimates obtained by the three techniques, suggesting that each technique captured a different aspect of local bumblebee population size and distribution in the landscape. Bumblebee abundance as observed on the transects was positively influenced by the number of flowers present on the transect. The number of bumblebees caught in pan traps was positively influenced by the density of flowers surrounding the trapping location and negatively influenced by wider landscape heterogeneity. Molecular estimates of the number of nests of Bombus terrestris and B. hortorum were positively associated with the proportion of the landscape covered in oilseed rape and field beans. Both direct survey techniques are strongly affected by floral abundance immediately around the survey site, potentially leading to misleading results if attempting to infer overall abundance in an area or on a farm. In contrast, whilst the molecular method suffers from an inability to detect sister pairs at low sample sizes, it appears to be unaffected by the abundance of forage and thus is the preferred survey technique. © 2015, Springer-Verlag Berlin Heidelberg. Source

Bunnefeld N.,Imperial College London | Reuman D.C.,Imperial College London | Baines D.,The Game and Wildlife Conservation Trust | Milner-Gulland E.J.,Imperial College London
Journal of Animal Ecology | Year: 2011

1.The effect of selective exploitation of certain age, stage or sex classes (e.g., trophy hunting) on population dynamics is relatively well studied in fisheries and sexually dimorphic mammals. 2.Harvesting of terrestrial species with no morphological differences visible between the different age and sex classes (monomorphic species) is usually assumed to be nonselective because monomorphicity makes intentionally selective harvesting pointless and impractical. But harvesting of the red grouse (Lagopus lagopus scoticus), a monomorphic species, was recently shown to be unintentionally selective. This study uses a sex- and age-specific model to explore the previously unresearched effects of unintentional harvesting selectivity. 3.We examine the effects of selectivity on red grouse dynamics by considering models with and without selectivity. Our models include territoriality and parasitism, two mechanisms known to be important for grouse dynamics. 4.We show that the unintentional selectivity of harvesting that occurs in red grouse decreases population yield compared with unselective harvesting at high harvest rates. Selectivity also dramatically increases extinction risk at high harvest rates. 5.Selective harvesting strengthens the 3- to 13-year red grouse population cycle, suggesting that the selectivity of harvesting is a previously unappreciated factor contributing to the cycle. 6.The additional extinction risk introduced by harvesting selectivity provides a quantitative justification for typically implemented 20-40% harvest rates, which are below the maximum sustainable yield that could be taken, given the observed population growth rates of red grouse. 7.This study shows the possible broad importance of investigating in future research whether unintentionally selective harvesting occurs on other species. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society. Source

Jacobs J.H.,Rothamsted Research | Clark S.J.,Rothamsted Research | Denholm I.,Rothamsted Research | Goulson D.,University of Stirling | And 2 more authors.
Arthropod-Plant Interactions | Year: 2010

Flowers of common ivy (Hedera helix L.) provide late season pollen and nectar for several insect groups, and its fruits are a winter and spring food source for frugivorous birds. Ivy benefits from insect pollination in order to set fruit, but it is unknown which flower-visiting insects are the most effective pollinators. Our observations suggest that Vespula wasps are potentially the most effective pollinators since they were frequent visitors, had relatively fast foraging rates, carried large numbers of pollen grains on their bodies and had the highest 'Pollination potential PP index' score (a measure of pollinator effectiveness) of all the insect groups examined. There was also a positive linear relationship between the proportion of ivy flowers that set fruit and wasp foraging activity in 0.5m2 quadrats. Visits by Vespula wasps may therefore be important for ensuring a supply of ivy fruits for birds. © Springer Science+Business Media B.V. 2009. Source

Clay G.D.,Durham University | Worrall F.,Durham University | Aebischer N.J.,The Game and Wildlife Conservation Trust
Journal of Hydrology | Year: 2012

Prescribed burning of moorland, heathland and blanket bog vegetation on peatlands in the UK is a contentious issue. Given the large carbon store in these peatlands, concern has been raised over land management and its effect on the carbon dynamics of peat ecosystems. In particular the spatial and temporal link between burning and concentrations of dissolved organic carbon (DOC) in waters draining these catchments has received particular attention. This study investigates water colour and DOC concentrations in soil pore water and runoff water at the plot-scale over a chronosequence of burn ages. Results from this study show that there is an elevated water colour in the few years immediately following burning but that this is not matched by a rise in DOC concentration. Therefore we propose that burning appears to affect the composition of the DOC rather than the absolute DOC concentration. This study also highlights that in some cases the use of water colour as a proxy for DOC concentration should be treated with caution. © 2012 Elsevier B.V.. Source

Wood T.J.,University of Sussex | Holland J.M.,The Game and Wildlife Conservation Trust | Goulson D.,University of Sussex
Biological Conservation | Year: 2015

In order to reverse declines in pollinator populations, numerous agri-environment schemes have been implemented across Europe, predominantly focused on increasing the availability of floral resources. Whilst several studies have investigated how bees and wasps (aculeates) respond to management at the scale of the scheme (i.e. within the flower patch) there has been little assessment of how schemes affect diversity at the farm scale. In the current work we assessed whether farms implementing flower-rich schemes had richer aculeate communities than farms without such habitats. A total of 104 species of bee and 44 species of aculeate wasp were recorded. Farms providing flower-rich habitats had significantly greater floral abundance but there were no differences in the total number of aculeate or flowering plant species recorded compared to farms without these habitats. After accounting for differences in sample size, and contrary to expectations, farms without flower-rich habitats were significantly richer in aculeate and flowering plant species. Bumblebees (. Bombus spp.) and honeybees (. Apis mellifera) foraged strongly from sown flowers, but the majority of bee species preferred wild plants that are not included in flower-rich schemes such as Heracleum sphondylium, Hypochaeris radicata and Tripleurospermum inodorum. The creation of pollinator-friendly habitats has not increased the diversity of flowering plants and such schemes will consequently only benefit a limited suite of aculeate species. If diverse aculeate communities are to be retained and restored on farmland, agri-environment schemes that provide foraging and nesting resources for a wider range of pollinator species must be developed. © 2015 Elsevier Ltd. Source

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