Resumen de Farmland habitat diversity in Ireland
H. Sheridan, B. Keogh, A. Anderson, T. Carnus, B. J. McMahon, Stuart Green, G. Purvis
While appreciation of the fundamental role biodiversity plays in underpinning the long-term sustainability of agricultural systems is growing, international commitments to preserve and protect this natural resource have not yet been achieved. Loss and degradation of farmland habitats are an important contributor to the continued decline of biodiversity. Despite this, little information is available regarding the diversity and ecological condition of farmland habitats in Europe. Indeed, where habitat data are available, this is usually at a very broad landscape scale rather than farm scale. Coupled with this, strategies to increase agricultural output in response to growing global population, will likely place increasing pressure on farmland biodiversity. Knowledge and ongoing monitoring of farmland habitat type and extent is a prerequisite for the future protection of much of Europe’s biodiversity. Here we report the findings of a national scale survey of farmland habitat diversity in Ireland.
Detailed surveys of farm habitats and management practices (system, stocking rate agri-environment scheme participation status and organic N and P inputs) were undertaken on 118 farms in three regions of the Republic of Ireland (RoI). Recorded farm habitats were subsequently digitised on orthophotography. The resulting ground truthed data from the total surveyed area of 3688 ha, were then used, together with satellite imagery, to classify the habitat composition of a further approximately 87,000 ha of the surrounding landscape.
Results revealed that at individual farm scale, an average of 73% of the land surveyed comprised agriculturally productive (mainly improved grassland) habitats. Marginally productive habitats (mainly extensively managed grasslands) accounted for an average of 11% of farm area, while other semi-natural habitats (mainly hedgerows) accounted for an average of 13%, with the remaining ca. 3% under build ground. Results from the classification at the wider landscape scale showed a similarly substantial incidence of non-intensively managed habitats. However, at both farm and landscape scales, habitat diversity was found to vary markedly between different regions and farming systems.
This study represents one of a very small number that currently exist, where farm scale habitat and management data have been collected. From the few that are available, semi-natural habitat cover has been found to account for an average farm area of 1–12%. Therefore, our data present a relatively positive picture in terms of the intensity, scale and impact of Irish farming on landscape heterogeneity. However, as in other parts of the world, agricultural expansion and intensification to meet increased global food supply will necessitate careful monitoring of the impact of these changes on the structure of farmed landscapes. This study provides a novel approach for the collection of such monitoring data at farm scale, and illustrates how such data can be reliably up-scaled to landscape level.
