Species assemblages across the deforestation gradient:
winners and losers
Ordinations based on Bray-Curtis dissimilarity of sandfly species
relative abundance (k = 2; stress = 0.11) and vertebrate species
relative abundance (k = 2; stress=0.18) show that there is no clear
separation of the vector and the non-vector communities nor the host and
the non-host communities in ordination space (Fig. 4 left side panels).
However, these ordinations reveal that the relative abundance of
individual species differed across the environmental gradients with most
of the sandfly species ordinated closer to increased forest intactness
and away from the most heavily deforested sites with minimum forest
cover (Fig. 4 top left panel) and that many important host species align
along the percentage pasture vector (Fig. 4 bottom left panel).
Regression models more clearly show the responses of individual species
to deforestation (Fig. 4 right side panels; Appendix S1: Table S2).
Higher pasture land cover was a significant negative predictor of the
probability of encountering a vector (p = 0.04) and the vector genusNyssomyia spp. (p = 0.03), while higher forest cover was an
important predictor of the probability of encountering the vector
species Psychodopygus davisi (p = 0.10). The most important
finding from sandflies feeding on vertebrate species showed that
decreasing forest cover was a significant predictor of the probability
of finding a sylvatic host in a sandfly pool (p < 0.05), as
well as the probability of finding the most competent host species
(nine-banded armadillo) in a sandfly pool (p < 0.05) (Fig. 4
bottom right panel; Appendix S1: Table S2).