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Aleutian Tern Onychoprion aleuticus numbers in Alaska appear to be in decline; however, colonies are difficult to count for the purposes of monitoring due to their co-occurrence with Arctic Terns Sterna paradisaea, low nesting densities, high variability in attendance, sensitivity to human disturbance, and remote terrain. We paired visual observations with unmanned aerial systems (UASs) to test the feasibility of using this technology to survey a small colony of nesting Arctic and Aleutian terns in southcentral Alaska. We used counts of terns in the air and nest attendance to test for disturbance from UAS flights. We conducted 11 UAS flights over seven days at altitudes ranging from 15-30 m and located 23 nests in the 4.1 ha (0.041 km²) colony site (5.6 nests ha-1) by systematically searching the orthomosaics. We were most likely to distinguish tern species in the 18-m and 15-m altitude photos; the white forehead was most visible in side angle rather than top-down. Nest attendance and the number of aerial birds were not influenced by the UAS in this colony, which experiences high Larus gull activity. Aleutian Terns arrived on 19 May and were attending nests by 02 June; nest attendance declined throughout June. We believe the best approximation of total nesting pairs will be achieved by counting nests 7-10 d after first initiation. In mixed species colonies, we recommend that UASs fly in a 'lawn mower' pattern with overlap to maximize side angle images and aim for an image resolution of < 4 mm (which was achieved by 15-m altitude flights with our camera setup). In single species colonies, 30 m is sufficient and can be achieved more efficiently. [ABSTRACT FROM AUTHOR]

Background By the end of this century, the potential climate-biome of the southern Kenai Peninsula is forecasted to change from transitional boreal forest to prairie and grasslands, a scenario that may already be playing out in the Caribou Hills region. Here, spruce (Picea × lutzii Little [glauca × sitchensis]) forests were heavily thinned by an outbreak of the spruce bark beetle (Dendroctonus rufipennis (Kirby, 1837)) and replaced by the native but invasive grass species, Calamagrostis canadensis (Michx.) P. Beauv. As part of a project designed to delimit and characterize potentially expanding grasslands in this region, we sought to characterize the arthropod and earthworm communities of these grasslands. We also used this sampling effort as a trial of applying high-throughput sequencing metabarcoding methods to a real-world inventory of terrestrial arthropods. New information We documented 131 occurrences of 67 native arthropod species at ten sites, characterizing the arthropod fauna of these grasslands as being dominated by Hemiptera (60% of total reads) and Diptera (38% of total reads). We found a single exotic earthworm species, Dendrobaena octaedra (Savigny, 1826), at 30% of sites and one unidentified enchytraeid at a single site. The utility of high-throughput sequencing metabarcoding as a tool for bioassessment of terrestrial arthropod assemblages was confirmed. [ABSTRACT FROM AUTHOR]