The detection of fish by using environmental DNA (eDNA) analysis has been shown to be more cost‐effective than traditional sampling methods are in certain situations, but this method has not been assessed under extreme winter conditions. We conducted a multiyear pilot study to test the effectiveness of eDNA for detecting fish under ice. In the spring of 2016, 2017, and 2018, we sampled for juvenile Chinook Salmon Oncorhynchus tshawytscha in the Tanana Flats (Alaska, USA) by using minnow traps and by using eDNA in the spring of 2017 and 2018. We used traps at 97 sites and analyzed eDNA that was isolated from water samples at 36 sites, using an established, species‐specific quantitative polymerase chain reaction (qPCR) assay for Chinook Salmon. We detected Chinook Salmon by using eDNA at 12 of the 36 eDNA‐sampled sites but did not capture any live juveniles in the minnow traps. Assuming that positive eDNA detections are reliable indicators of recent fish presence, we found that eDNA can be a more efficient and cost‐effective alternative for monitoring aquatic communities under extreme winter conditions. Based on our experience, including eDNA‐based screening of target sampling sites could prove to be a significant boost to the effectiveness of fish monitoring in remote and challenging habitats.
Interior Alaska, USA, is the least‐studied region in Alaska for breeding shorebirds because of challenging accessibility and expectations of low densities and abundances. We estimated lowland and upland shorebird population sizes on 370,420 ha of military lands in interior Alaska boreal forest from May–July 2016 and 2017. We modified the Program for Regional and International Shorebird Monitoring (PRISM) protocol used elsewhere in Alaska and incorporated a probability‐based sampling design and dependent double‐observer methods. We pooled all lowland shorebird and all upland shorebird observations and estimated abundance using Huggins closed captures models in Program MARK. Estimated abundances of all lowland and upland shorebirds were 42,239 ± 13,431 (SE) and 3,523 ± 494, respectively. The survey area is important for shorebirds in Alaska. We estimate that military lands in interior Alaska support 45,762 ± 13,925 shorebirds, including 7 species of conservation concern. Higher abundance of lowland shorebirds was best explained by lower elevation, lower percent scrub canopy, and higher percent water on plots. Higher abundance of upland shorebirds was best explained by higher elevation and increased distance to wetland. Our modified Arctic PRISM protocol was effective for surveys in the boreal forest and we recommend continued use of method modifications for future shorebird surveys in boreal forests. Identifying baseline abundances of shorebirds using interior Alaska is an important step in monitoring distributional shifts and potential future population declines. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.
Evaluating sympatric habitat use of a mammal community can help determine intra- and inter-guild interactions and identify important habitats, potentially improving the management of these communities with a changing climate. Increasingly variable climatic patterns in Alaska, USA, are raising concerns of mismatched phenologies and altered ecosystem structures. We studied the occupancy of 10 mammal species over 15 months, via camera traps, occupying alpine areas of the Alaska Range in interior Alaska, from 2013 to 2014. We tested hypotheses about how habitat use of these species within and between groups varied by spatial and temporal covariates. Furthermore, we modeled two-species occupancy of brown bears (Ursus arctos Linnaeus, 1758) and gray wolves (Canis lupus Linnaeus, 1758) against different potential prey species. Our results suggest that medium-sized and large herbivore use was positively correlated with fine-scale covariates including rock, forb, and graminoid coverage. Large herbivore habitat use was also correlated with abiotic landscape covariates. Detection probabilities of predators and Dall’s sheep (Ovis dalli dalli Nelson, 1884) was improved by camera traps on wildlife trails. Two-species models suggested co-occurrence of habitat use between brown bear – caribou (Rangifer tarandus (Linnaeus, 1758)) and gray wolf – caribou. Results demonstrate the sympatric habitat use by multiple groups of mammals within Alaskan alpine ecosystems and the importance of incorporating multiple groups and spatial scales when making management decisions.
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