Predator-prey time series: Monthly densities of least Killifish and Eastern Mosquitofish over five years

Individual predator and prey species exhibit coupled population dynamics
in simple laboratory systems and simple natural communities.  It
is unclear how often such pairwise coupling occurs in more complex
communities, in which an individual predator species might feed on several
prey species and an individual prey species might be attacked by several
predators.  To examine this problem, we applied multivariate
autoregressive state-space (MARSS) models to five-year time series of
monthly surveys of a predatory fish, the Eastern Mosquitofish (Gambusia
holbrooki), and its littoral zone prey species, the least Killifish
(Heterandria formosa), in three locations in north Florida.  The
MARSS models were consistent with coupled predator-prey dynamics at two of
the three locations.  In one of these two locations, the
estimated densities of the two species displayed classic predator-prey
oscillations.  In the third location, there was a positive effect
of Killifish density on Mosquitofish density but no detectable effect of
Mosquitofish density on Killifish density.  In all three
locations, increased submergent vegetation cover was associated with
increased prey density but not increased predator density. 
Eigenvalues analyses for the joint dynamics indicated that all three
systems would return to their respective stationary distributions of
density if perturbed.  The three different patterns demonstrate
that the dynamics of a pairwise predator-prey interaction emerge not only
from the characteristics of the prey and the predator, but also those of
the habitat and trophic web in which the predator and prey are
embedded.