The focus should then be on the abiotic and biotic factors specific to this edge which may interact to cause such an effect.

Abiotic Factors

Edge contrast may be playing an important role on this forest edge. The bordering habitat to the forest is open grassland, which is capable of supporting high densities of opportunistic generalist predators \cite{Lahti_2001}. It's also been suggested that the steepness of the gradient in productivity over an ecotone may play a role in nest predation, and that such an effect is exaggerated by high levels of habitat fragmentation \cite{Angelstam_1986}. Lahti et al.'s meta-analysis did not show such an effect, however it did show that a edge effect on nest predation is significantly less likely where the gradient in productivity is shallow (e.g grassland and agricultural land). This suggests steepness of ecotone productivity gradients only increases nest predation conditionally, subject to other factors.