The effect of construction activity on internationally important waterfowl species

Abstract Large-scale construction activity associated with the enlargement of Abberton Reservoir in Essex, England was calculated, mapped and subsequently modelled to examine the effect of disturbance on four Special Protection Area designated dabbling waterfowl species, Anas strepera (Gadwall), A . clypeata (Shoveler), A . crecca (Teal) and A . penelope (Wigeon). The distribution of each species was compared with levels of construction disturbance and environmental variables using Hurdle Model analysis and spatial referencing. Numbers of all four species varied throughout the study period with significant increases observed across the reservoir during the four year construction period. Findings show that the most important environmental variable was shallow water with increases in this area of habitat as a result of planned enhancement measures being of particular benefit to Gadwall, Shoveler and Teal. Numbers of Wigeon were especially variable across the site during construction and were displaced from the Main Section during the most disturbing shoreline works, behaviour we attribute to the loss of suitable grazing habitat during the construction process. While results show some disturbance responses, maintenance of site integrity for all four species is attributed to the overall size of the reservoir complex (4.75 km 2 ) and the phased construction programme which reduced the extent and impact of disturbance. Research presented here provides evidence for a sensitive and science based approach to better deliver conservation and development requirements. The monitoring prior to (2006–2009) and during the construction phase (2010−2013) has enabled the much needed, but often lacking, evidence-based reporting on construction disturbance effects and associated mitigation measures.