The Aquatic Surface Robot (AnSweR), a lightweight, low cost, multipurpose unmanned research vessel

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Springer in Communications in Computer and Information Science on 15/03/2021.Available online: https://link.springer.com/chapter/10.1007/978-3-030-71711-7_21acceptedVersio

Endozoochory by brown bears stimulates germination in bilberry

The understory vegetation of the Eurasian boreal forest is dominated by several ericaceous species (e.g. bilberry Vaccinium myrtillus). These species invest large amounts of energy in their sexual reproduction by producing seed-containing berries, which are apparent adaptations for endozoochory. Their seedlings are, however, almost never found in the wild, and they reproduce virtually exclusively through clones. Brown bears Ursus arctos consume enormous amounts of ericaceous berries (predominantly bilberry in central Scandinavia) during hyperphagia, and may facilitate sexual reproduction in such species. If ericaceous species would benefit from endozoochory by brown bears, one would predict that endozoochory would have no negative impacts on germination. We experimentally evaluated this prediction using germination trials under controlled conditions of bilberry seeds that were 1) extracted from brown bear feces, 2) extracted from ripe berries and 3) contained in berries. Using time-to-event analyses, we showed that passing the gut by itself did not stimulate or limit germination. However, seeds that were released from the berries germinated about one month earlier compared to seeds contained in berries. This implies that being released from a fruit, for example through endozoochory, can have a large temporal germination and growth advantage, especially in northern ecosystems a with short growing season.publishedVersio

Beaver (Castor fiber) activity and spatial movement in response to light and weather conditions

Animal behaviour can affect individual fitness and is influenced by exogenous and endogenous factors. Here, we investigated how light (daylight length and moonlight), weather (precipitation and temperature), age, sex and social status affected activity and movement of a semiaquatic mammal, the Eurasian beaver (Castor fiber), using GPS relocation data from 47 individuals in south-eastern Norway. Independent of daylight length, beavers had a mean daily activity time of 9:42 h and reduced their activity periods when they were older, most likely due to senescence. In line with this, older individuals also spent less time in water and moved shorter distances. Furthermore, beavers reduced their activity periods in drier weather conditions and spent less time on land during brighter nights and drier conditions, indicating a predation risk avoidance strategy. Individuals spent less time in the water during the colder parts of the year and moved shorter distances with decreasing temperature, suggesting thermal constraints. Our study adds to the increasing amount of evidence that animal behaviour is modulated by various endogenous and exogenous factors, and that weather conditions can affect their behaviour. It remains to be tested, however, how climate variability together with hunting and predation pressure affect space use and demography in species such as the Eurasian beaver.publishedVersionPaid Open Acces

Differentiation and seasonality in suitable microsites of seed dispersal by an assemblage of omnivorous mammals

acceptedVersio

Reindeer carcasses provide foraging habitat for insectivorous birds of the alpine tundra

On August of 2016, almost an entire herd (n = 323) of wild tundra reindeer (Rangifer tarandus) was killed by lightning on Hardangervidda in southern Norway. While conducting fieldwork for another study in 2017, we opportunistically registered the occurrence and behaviour of birds on carcasses from this mass die-off. Several passerine species other than corvids were observed actively foraging on arthropods, such as blowfly (Calliphoridae sp.) adults and larvae, which are typically associated with carcass decomposition. We quantified observations of those birds, and described their foraging behaviour at the carcass site. In decreasing order of abundance, five passerine species were observed taking arthropods at the site: Meadow Pipit (Anthus pratensis), Northern Wheatear (Oenanthe oenanthe), Common Reed Bunting (Emberiza schoeniclus), Bluethroat (Luscinia svecica,), and Lapland Bunting (Calcarius lapponicus). Systematic surveys of passerines utilizing carcass sites would further our understanding of how such resources may affect behaviour and life history of various bird species

Perfect poopers; passerine birds facilitate sexual reproduction in clonal keystone plants of the boreal forest through directed endozoochory towards dead wood

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Directed endozoochorous dispersal by scavengers facilitate sexual reproduction in otherwise clonal plants at cadaver sites

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A human-induced landscape of fear influences foraging behavior of brown bears

Animals adapt their foraging behavior to variations in food availability and predation risk. In Sweden, brown bears (Ursus arctos) depend on a nearly continuous intake of berries, especially bilberries (Vaccinium myrtillus) during late summer and early autumn to fatten up prior to hibernation. This overlaps with the bear hunting season that starts on 21 August. Bilberry occurrence varies across space, as does human-induced mortality risk. Here, we hypothesize that brown bears select for areas with a high probability of bilberry occurrence across a boreal forest ecosystem in Sweden (H1), and that human-induced mortality risk reduces bear selection for bilberries (H2). In addition, we hypothesized that bears that survived the hunting season avoided bilberry areas associated with high risk, whereas bears that were later killed selected more strongly for berries and less against risk prior to the hunting season (H3). To evaluate our hypotheses, we used resource selection functions to contrast bear GPS relocation data (N = 35, 2012–2015) and random positions within the bearś home range with generalized linear mixed effect models against two focal variables: a map predicting bilberry occurrence and a map predicting human-induced mortality risk. We found that bears selected for areas with a high probability of bilberry occurrence (supporting H1), but avoided these areas if they were associated with and high risk of hunting mortality (supporting H2). The killed and surviving bears did not differ in their selection for bilberries, but they did differ in their selection against risk (partially supporting H3). Surviving bears strongly avoided high risk areas, whereas killed bears responded less to risk and selected for high-risk areas with a low probability of bilberry occurrence. This suggests that killed bears selected for other food sources than berries in high risk areas, which exposed them to human hunters. We conclude that bears respond to a landscape of fear during the berry season and that different foraging strategies may have a direct impact on individual mortality during the hunting season.acceptedVersio

Animal-borne video systems provide insight into the reproductive behavior of the Asian black bear

Previous studies on the mating system of the Asian black bear (Ursus thibetanus) have been limited to observations of captive populations and estimations of multiple paternities. Hence, the mating system of wild bears remains poorly understood. Animal-borne camera systems (i.e., cameras mounted on animals) provide novel tools to study the behavior of elusive animals. Here, we used an animal-borne video system to record the activities of wild bears during the mating season. Video camera collars were attached to four adult Asian black bears (male “A” and “B,” and female “A” and “B”) captured in Tokyo, central Japan, in May and June 2018. The collars were retrieved in July 2018, after which the video data were downloaded and analyzed in terms of bear activity and mating behavior. All the bears were found to interact with other uniquely identifiable bears for some of the time (range 9–22 days) during the deployment period (range 36–45 days), and multiple mating in males was documented. Both males and females exhibited different behaviors on social days (i.e., days when the bear interacted with conspecifics) compared with solitary days (i.e., days with no observed interactions with conspecifics). Compared with solitary days, the bears spent a lower proportion of time on foraging activities and higher proportion of time on resting activities on social days. Our results suggest that Asian black bears have a polygamous mating system, as both sexes consort and potentially mate with multiple partners during a given mating season. Furthermore, bears appeared to reduce their foraging activities on social days and engaged more in social interactions.publishedVersio

Animal-borne video systems provide insight into the reproductive behavior of the Asian black bear

Previous studies on the mating system of the Asian black bear (Ursus thibetanus) have been limited to observations of captive populations and estimations of multiple paternities. Hence, the mating system of wild bears remains poorly understood. Animal-borne camera systems (i.e., cameras mounted on animals) provide novel tools to study the behavior of elusive animals. Here, we used an animal-borne video system to record the activities of wild bears during the mating season. Video camera collars were attached to four adult Asian black bears (male “A” and “B,” and female “A” and “B”) captured in Tokyo, central Japan, in May and June 2018. The collars were retrieved in July 2018, after which the video data were downloaded and analyzed in terms of bear activity and mating behavior. All the bears were found to interact with other uniquely identifiable bears for some of the time (range 9–22 days) during the deployment period (range 36–45 days), and multiple mating in males was documented. Both males and females exhibited different behaviors on social days (i.e., days when the bear interacted with conspecifics) compared with solitary days (i.e., days with no observed interactions with conspecifics). Compared with solitary days, the bears spent a lower proportion of time on foraging activities and higher proportion of time on resting activities on social days. Our results suggest that Asian black bears have a polygamous mating system, as both sexes consort and potentially mate with multiple partners during a given mating season. Furthermore, bears appeared to reduce their foraging activities on social days and engaged more in social interactions.publishedVersio