Data from: Abiotic conditions mediate intraguild interactions between mammalian carnivores

1. Intraguild (IG) interactions are common among mammalian carnivores, can
include intraguild predation (IGP) and interspecific killing (IK), and are
often asymmetrical, where a larger more dominant species (IGpredator)
kills a smaller one (IGprey). According to ecological theory, the
potential for a IGpredator and IGprey to coexist depends on whether the
direct consumptive benefits for the IGpredator are substantial (IGP) or
insignificant (IK), the extent to which the IGprey is the superior
exploitative competitor on shared prey resources, and overall ecosystem
productivity. 2. We used resource selection models and spatially-explicit
age and harvest data for two closely related mesopredators that engage in
IG interactions, American martens (Martes americana; IGprey) and fishers
(Pekania pennanti; IGpredator), to identify drivers of distributions,
delineate areas of sympatry and allopatry, and explore the role of an apex
predator (coyote; Canis latrans) on these interactions. 3. Model selection
revealed that fisher use of this landscape was strongly influenced by late
winter abiotic conditions, but other bottom-up (forest composition) and
top-down (coyote abundance) factors also influenced their distribution.
Overall, fisher probability of use was higher where late winter
temperatures were warmer, snowpack was deeper, and measures of
productivity were greater. Martens were constrained to areas of the
landscape where the probability of fisher use, coyote abundance, and
productivity were low and selected for forest conditions that presumably
maximized prey availability. Marten age data indicated an increased
proportion of juveniles outside of the predicted area of sympatry,
suggesting that few animals survived >1.5 years in this area that
supported higher densities of fishers. 4. Consistent with asymmetrical IG
interaction theory, the IGpredator (fishers and, to a lesser degree,
coyotes) competitively excluded the IGprey (martens) from highly
productive, milder temperature habitats, whereas IGpredators and IGprey
coexisted in low productivity environments, where a combination of abiotic
and biotic conditions enabled the IGprey to be the superior exploitative
competitor.