Monitoring program and assessment of coyote predation for Olympic Marmots

Abstract

The Olympic marmot (Marmota olympus) is an endemic species to the Olympic Peninsula, Washington State. Although nearly all of its range is enclosed within Olympic National Park, declines and local extirpations of the species have been documented. The most plausible driver of the decline appears to be an increase in predator pressure. My thesis had two main objectives. First, I investigated the role of non-native coyotes (Canis latrans) in causing marmot mortality. Through park-wide carnivore scat analysis I determined the spatial extent of coyote predation on Olympic marmots and the magnitude of coyote predation relative to other carnivore species. I used mtDNA analysis of scats to determine carnivore species and microsatellite markers for individual coyote identification. Out of 958 carnivore scats collected, 84% came from coyotes and 10.3% contained marmots. The proportion of scats containing marmots was highly variable across studied regions, ranging from 3% to 34%. Among 79 scats with marmot remains for which predator species identification with mtDNA was successful, 85% arose from coyote, 10% from bobcat (Lynx rufus) and 5% from cougar (Puma concolor). Twelve out of 13 coyote individuals identified with genetic markers included marmots in their diet. Overall, occurrence of marmot remains in coyote scats observed could be considered high, especially if relatively low marmot densities are taken into account, supporting the potential for coyote predation to be the main driving factor of the observed marmot declines and extinctions. For my second objective, I designed a large scale, long-term monitoring program for marmot populations in Olympic National Park accounting for financial constraints. The monitoring program is designed to reflect extinctionrecolonisation dynamics via park-wide occupancy sampling. The sampling design is based on annual surveys of a set of at least 25 randomly selected clusters (closely located groups of polygons with record of current or historical occupancy by marmots), and 15 additional polygons to test for colonisations.