Assessing waterbird conservation objectives: An example for the Burry Inlet, UK
Authored by Richard A Stillman, J J Moore, A P Woolmer, M D Murphy, P Walkere, K R Vanstaen, D Palmer, W G Sanderson
Date Published: 2010
DOI: 10.1016/j.biocon.2010.07.004
Sponsors:
No sponsors listed
Platforms:
MORPH
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
We use an individual-based model to assess the conservation objectives
for knot Calidris canutus L and oystercatcher Haematopus ostralegus L on
the Burry Inlet Special Protection Area (SPA), UK. Population monitoring
has identified a decline in oystercatcher numbers, but cannot determine
whether this is due to a decline in site quality. Long term data on
cockle stocks show that the biomass of the large-sized cockles consumed
by oystercatcher declined after 2004, whereas a similar decline was not
observed in the smaller cockles consumed by knot. The model postdicts
that during the winters of 2005/2006 to 2008/2009 the site was unable to
support the number of oystercatcher present at the time it was
designated (i.e. the SPA population). Large cockle biomass remained low
during 2009/2010, but increases in mussel biomass meant that the model
postdicted that the site could support the SPA population of
oystercatcher. Knot food supplies remained high during most years, except 2008/2009 during which the model postdicted that the SPA
population could not be supported. The model postdicted that the stock
reserved for oystercatchers after shellfishing needed to be 2-4 times
the amount consumed by the birds in order to support the bird
population. We recommend that where necessary, the conservation
objectives of waterbirds should be assessed using a combination of
thorough population size and behaviour monitoring to identify sites with
population declines, and individual-based modelling on these sites to
determine whether reduction in site quality may contribute to the
site-specific population decline. (C) 2010 Elsevier Ltd. All rights
reserved.
Tags
Populations
Consequences
Haematopus-ostralegus
Behavior-based model
Shorebird mortality
Energy-expenditure
Predicting site quality
Shellfishery management
Macoma-balthica
Oystercatcher