[Thesis]. Manchester, UK: The University of Manchester; 2016.
In an ever-changing world with an increasing human population, improving the efficiency
of conservation management strategies is vital to mitigate against continued losses
to global biodiversity. Empirical studies highlighting how species respond to environmental
change can provide evidence to enable the development of such strategies. There are
two strands of research explored in the current work that aim to address these issues.
The first is an analysis of changes in species distributions over time with respect
to environmental changes. The second is a critical comparison of behaviour, resource
use and population performance across ecological gradients within a species’ range.
In chapter two, local population changes (10 km2 spatial resolution) in 64 species
of British passerine were examined from 1970 and 1990. These were analysed using a
spatially explicit linear mixed effects model selection framework, which predicted
these changes in occupancy with respect to biological traits and environmental changes,
namely changes in human land use and climate. In chapter three, a more targeted approach
was used to investigate the variation in social network structure across ten independent
sub-populations of Cape mountain zebra, Equus zebra zebra, with respect to variation
in habitat availability, demography and population performance. In British passerines,
rare species with fragmented ranges were found to be the most likely to undergo local
extinctions. Furthermore, human land use was highlighted as a more reliable predictor
of local occupancy than climate change at this spatial and temporal resolution. Our
findings emphasize the need to increase and maintain diverse, interconnected networks
of appropriate habitat. For Cape mountain zebra, individual connectivity, group size,
the proportion of bachelors, and the ties of each adult male were all influenced by
the availability of palatable grass and water. In optimal habitat, there were more
connected individuals, larger groups and a smaller proportion of bachelors. Along
with other recent studies of the habitat preferences of Cape mountain zebra, our research
suggests that mesic habitats with a high availability of palatable grass are vital
to maintain productive populations with a higher proportion of heterogeneous family
groups. Understanding how species respond to environmental changes can only increase
in importance as human populations rise.