Agri-environment scheme enhances breeding populations of some priority farmland birds in Northern Ireland

<p><b>Capsule:</b> The abundance of Tree sparrow <i>Passer montanus</i>, House Sparrow <i>Passer domesticus</i> and Yellowhammer <i>Emberiza citrinella</i>, three priority farmland birds, increased over a 5-year period in response to a targeted agri-environment scheme (AES).</p> <p><b>Aims:</b> To assess the effects of a targeted AES on the abundance of a suite of farmland bird species over a 5-year period.</p> <p><b>Methods:</b> We compare temporal changes in abundance of 12 farmland bird species of conservation concern on 33 AES and 22 control farms in County Down, Northern Ireland. Five of these species were designated targets for conservation action under the Countryside Management Scheme (CMS).</p> <p><b>Results:</b> CMS management was associated with more positive changes in abundance for three of the five target species and more negative changes for one target species (albeit caused mainly by a large reduction at a single farm). CMS management had little influence on the abundance of non-target species or on avian species richness. Farm-scale changes in abundance were generally unrelated to the extent of local CMS provision, the only exception involved House Sparrow and seed-rich winter habitats.</p> <p><b>Conclusion:</b> This study demonstrates that generic AES land management can improve the population status of target farmland birds on farms with AES management.</p

Individual Genotypes

Individual Genotype

Environmental Conditions during Breeding Modify the Strength of Mass-Dependent Carry-Over Effects in a Migratory Bird

<div><p>In many animals, processes occurring in one season carry over to influence reproductive success and survival in future seasons. The strength of such carry-over effects is unlikely to be uniform across years, yet our understanding of the processes that are capable of modifying their strength remains limited. Here we show that female light-bellied Brent geese with higher body mass prior to spring migration successfully reared more offspring during breeding, but only in years where environmental conditions during breeding were favourable. In years of bad weather during breeding, all birds suffered reduced reproductive output irrespective of pre-migration mass. Our results suggest that the magnitude of reproductive benefits gained by maximising body stores to fuel breeding fluctuates markedly among years in concert with conditions during the breeding season, as does the degree to which carry-over effects are capable of driving variance in reproductive success among individuals. Therefore while carry-over effects have considerable power to drive fitness asymmetries among individuals, our ability to interpret these effects in terms of their implications for population dynamics is dependent on knowledge of fitness determinants occurring in subsequent seasons. </p> </div

Graph illustrating how the strength of mass-dependent carry-over effects is modulated by the environmental conditions during breeding.

<p>In years with positive June NAO (red line), representative of poor weather conditions during breeding, higher body mass does not yield an increase in reproductive success. Conversely, when breeding conditions are favourable (Negative June NAO, blue line), individuals with greater body mass return the following year with more offspring. The x axis represents body mass (as Scaled Mass Index) expressed in units of standard deviations from the mean, where ‘0’ represents an individual of average mass in the sample. Shaded areas span the 95% credible intervals for the fitted means. Points are raw data means for years with positive June NAO (triangles) and negative June NAO (circles), averaged over 1 SD bins of body mass and plotted at the midpoint of that bin. Point size is proportional to sample size per bin. Sample size per bin is displayed next to each point. Predictions for both good and poor environmental conditions are for ‘average' conditions in each scenario, being the mean of years with negative NAO residuals for ‘good’ years and mean positive residuals for ‘bad’ years. Note that as the data predict over values within 1.5 SD of mean body mass, some data at the tails of the distribution for body mass are excluded from the plot. </p