Current dynamics and predicted vulnerability to sea-level rise of a threatened Bittern Botaurus stellaris population


Corresponding author.


The decline of the Bittern Botaurus stellaris has long been symbolic of wetland habitat loss and fragmentation across western Europe. Wetland restoration and creation activity, targeted at Bittern, has been ongoing in the UK for more than 10 years and the overall numbers of occupied sites has increased five-fold in that time. The strong recovery, whilst cause for celebration, disguises the continued precariousness of the population. This recovery has predominantly been fuelled by chick productivity from three sites in coastal Suffolk and there is increasing awareness that these sites are in immediate danger from rising sea levels. A key question is whether any loss of these key sites to coastal flooding matters to the UK Bittern population. A cautious approach to mathematical modelling of the sensitivity of the UK Bittern population to sea-level rise events suggests that we should be concerned about the long-term future. Our models demonstrate the sensitivity of the UK population to changes in chick survival and suggest that the growth of the UK Bittern population would be negatively affected by the loss of even a proportion of nests from these three key sites. These findings prompt the need for a multi-layered conservation strategy to meet this dynamic challenge. A potential way forward is discussed.