HUMAN ACTIVITIES MAKE EXPLORATORY INDIVIDUALS CHANGE HABITATS
Proactive individuals are generally more active, explore more and are
more likely to disperse (Table 1). Consequently, in situations where
HIREC reduces habitat quality, proactive animals can be expected to be
the first individuals to leave. This has been previously observed in
crabs, where bold individuals were the first to disperse when habitat
quality was reduced (Belgrad & Griffen 2018). While studies conducted
in the wild are still lacking, some laboratory tests have shown that
bold individuals work harder to escape threatening situations. Bolder
fish have more attempts to escape laboratory-induced hypoxia (Brelinet al. 2005), or tend to avoid the hypoxic environment (Ferrariet al. 2016). Bold individuals are also better at avoiding or
escaping fishing gear (Diaz Pauli & Sih 2017), which could be related
to their higher anaerobic capacities (Table 1) (Killen et al.2015).
While leaving a non-suitable habitat might lead to a superior fitness
outcome for bold individuals of a given population, this implies that
they are subsequently able to successfully find suitable habitat. This
is not necessarily an easy task in the context of HIREC, which is often
characterized by overall habitat degradation and increases in the
presence of ecological traps (Robertson et al. 2013).
Previous studies have also found inter-individual differences within a
population in the propensity to disperse. Indeed, populations are likely
comprised of individuals that differ in consistent ways; dispersers are
bold, aggressive and asocial while joiners are rather shy,
slow-explorers and social (Cote et al. 2010a). Harrison et al.
(Harrison et al. 2015) also recently differentiated ‘resident’
from ‘mobile’ individuals. Mobile individuals tend to explore more, be
more active and be less site-specific, and thus, they resemble proactive
individuals. In this sense, less socially embedded yearling female
marmots (Marmota flaviventer ) are also more likely to disperse
(Blumstein et al. 2009), and in the month preceding dispersal
these marmots upregulate a suite of specific genes, many of which are
associated with migration (Armenta et al. 2018). Consequently, in
many cases mobile (or proactive) individuals are more prone to change
habitats in stressful situations related to HIREC (Fig. 1.1) and this
may have evolutionary consequences.