| 1. |
- Aikens, Ellen O., et al.
(författare)
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Wave-like Patterns of Plant Phenology Determine Ungulate Movement Tactics
- 2020
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Ingår i: Current Biology. - Cambridge : Cell Press. - 0960-9822 .- 1879-0445. ; 30:17, s. 3444-3449
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Tidskriftsartikel (refereegranskat)abstract
- Animals exhibit a diversity of movement tactics [1]. Tracking resources that change across space and time is predicted to be a fundamental driver of animal movement [2]. For example, some migratory ungulates (i.e., hooved mammals) closely track the progression of highly nutritious plant green-up, a phenomenon called "green-wave surfing" [3-5]. Yet general principles describing how the dynamic nature of resources determine movement tactics are lacking [6]. We tested an emerging theory that predicts surfing and the existence of migratory behavior will be favored in environments where green-up is fleeting and moves sequentially across large landscapes (i.e., wave-like green-up) [7]. Landscapes exhibiting wave-like patterns of green-up facilitated surfing and explained the existence of migratory behavior across 61 populations of four ungulate species on two continents (n = 1,696 individuals). At the species level, foraging benefits were equivalent between tactics, suggesting that each movement tactic is fine-tuned to local patterns of plant phenology. For decades, ecologists have sought to understand how animals move to select habitat, commonly defining habitat as a set of static patches [8, 9]. Our findings indicate that animal movement tactics emerge as a function of the flux of resources across space and time, underscoring the need to redefine habitat to include its dynamic attributes. As global habitats continue to be modified by anthropogenic disturbance and climate change [10], our synthesis provides a generalizable framework to understand how animal movement will be influenced by altered patterns of resource phenology.© 2020 Elsevier Inc.
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| 2. |
- Broekman, Maarten J. E., et al.
(författare)
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Evaluating expert-based habitat suitability information of terrestrial mammals with GPS-tracking data
- 2022
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 31:8, s. 1526-1541
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert-based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert-based information with detailed empirical evidence. Here, we compared expert-based habitat suitability information from the International Union for Conservation of Nature (IUCN) with habitat suitability information derived from GPS-tracking data of 1,498 individuals from 49 mammal species.Location: Worldwide.Time period: 1998-2021.Major taxa studied: Forty-nine terrestrial mammal species.Methods: Using GPS data, we estimated two measures of habitat suitability for each individual animal: proportional habitat use (proportion of GPS locations within a habitat type), and selection ratio (habitat use relative to its availability). For each individual we then evaluated whether the GPS-based habitat suitability measures were in agreement with the IUCN data. To that end, we calculated the probability that the ranking of empirical habitat suitability measures was in agreement with IUCN's classification into suitable, marginal and unsuitable habitat types.Results: IUCN habitat suitability data were in accordance with the GPS data (> 95% probability of agreement) for 33 out of 49 species based on proportional habitat use estimates and for 25 out of 49 species based on selection ratios. In addition, 37 and 34 species had a > 50% probability of agreement based on proportional habitat use and selection ratios, respectively.Main conclusions: We show how GPS-tracking data can be used to evaluate IUCN habitat suitability data. Our findings indicate that for the majority of species included in this study, it is appropriate to use IUCN habitat suitability data in macroecological studies. Furthermore, we show that GPS-tracking data can be used to identify and prioritize species and habitat types for re-evaluation of IUCN habitat suitability data.
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| 3. |
- Büntgen, Ulf, et al.
(författare)
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Horn growth variation and hunting selection of the Alpine ibex
- 2018
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 87:4, s. 1069-1079
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Tidskriftsartikel (refereegranskat)abstract
- 1. Selective hunting can affect demographic characteristics and phenotypic traits of the targeted species. Hunting systems often involve harvesting quotas based on sex, age and/or size categories to avoid selective pressure. However, it is difficult to assess whether such regulations deter hunters from targeting larger trophy animals with longer horns that may have evolutionary consequences.2. Here, we compile 44,088 annually resolved and absolutely dated measurements of Alpine ibex (Capra ibex) horn growth increments from 8,355 males, harvested between 1978 and 2013, in the eastern Swiss Canton of Grisons. We aim to determine whether male ibex with longer horns were preferentially targeted, causing animals with early rapid horn growth to have shorter lives, and whether such hunting selection translated into long-term trends in horn size over the past four decades.3. Results show that medium-to longer-horned adult males had a higher probability of being harvested than shorter-horned individuals of the same age and that regulations do affect the hunters' behaviour. Nevertheless, phenotypic traits such as horn length, as well as body size and weight, remained stable over the study period.4. Although selective trophy hunting still occurs, it did not cause a measurable evolutionary response in Grisons' Alpine ibex populations; managed and surveyed since 1978. Nevertheless, further research is needed to understand whether phenotypic trait development is coinfluenced by other, potentially compensatory factors that may possibly mask the effects of selective, long-term hunting pressure.
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| 4. |
- Jamemo, Anders, et al.
(författare)
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Avmagringssjuka (CWD) hos hjortdjur
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- • Chronic wasting disease (CWD) kallas på svenska avmagringssjukaoch drabbar hjortdjur. En smittsam variant av sjukdomen (även kalladklassisk CWD) påträffades 2016 hos norska vildrenar.• Senare har även atypiska varianter av CWD påträffats hos älg och kronvilti Norge och Finland. Under 2019 har CWD konstaterats hos tre älgkori Norrbotten. De svenska fallen liknar de norska fallen av CWD hosälg. Det är för närvarande oklart om atypisk CWD uppkommer spontant,och om den är smittsam.• CWD är en obotlig och utan undantag dödlig neurologisk prionsjukdomsom drabbar hjortdjur.• Sjukdomen är känd i Nordamerika sedan 1960-talet. Där har den hittillspåträffats hos åsnehjort, vitsvanshjort, wapiti, älg och ren. I Europa antas,förutom ren, älg och kronhjort, även rådjur vara mottagliga för smitta.Experiment tyder på att dovhjort är mindre mottaglig.• Inkubationstiden (tiden mellan smitta och uppvisande av symptom) äri genomsnitt 1,5-2,5 år, men kan vara längre.• Symptomen utgörs av kraftig avmagring, beteendeförändringar, stapplandegång, osynkroniserade rörelser, skakningar, tandgnissling, torr päls, hängandehuvud, ökad salivavsöndring och urinering, samt extrem törst.Symptomen utvecklas gradvis och inträffar först i senare stadier av sjukdomsförloppet,och de flesta smittade djur visar inga synliga sjukdomsteckenförrän efter lång tid.• CWD smittar genom direktkontakt mellan djur, men även indirekt viaväxter, jord och vatten. Smittämnet kan bevaras i miljön i flera år.• Smittan kan spridas till nya områden via långvandrande hjortdjur, menäven via asätare, flytt av renar eller hägnat hjortvilt samt transport avslaktkroppar eller slaktrester. Det är också möjligt att smitta kan spridas viakontaminerat foder, via människor med kontaminerade kläder och utrustningsamt via lockmedel för jakt som innehåller substanser från hjortdjur.• Andelen smittade djur i en population ökar långsamt, men antas gåsnabbare när miljön blir alltmer kontaminerad med smitta.• I USA finns exempel på hur CWD lett till en nedgång i hjortdjurspopulationeroch modellsimuleringar tyder på att populationer slutligen riskeraratt dö ut.• Det är i nuläget svårt att förutspå hur svenska populationer av hjortdjurskulle påverkas av sjukdomen. De långsiktiga konsekvenserna för såvälförvaltningen av hjortdjur som för rennäringen, skulle sannolikt bliallvarliga.• I nuläget finns inga bevis för att CWD kan överföras till människa. Riskenför att CWD är en zoonos (sjukdom som smittar mellan djur och människa)anses vara liten, men går inte att helt avfärda med dagens kunskap.Rekommendationen är dock att inte äta kött från djur med påvisad CWD.
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| 5. |
- Johansson, Maria, et al.
(författare)
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Livestock owners' worry and fear of tick-borne diseases
- 2020
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Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recent global changes have led to an increase in distribution of ticks towards higher elevation and latitude in Europe and livestock are at increasing risk of contracting tick-borne diseases, but psychological aspects of how this affects human well-being are rarely assessed. Departing from the theory on emotional appraisal coming from psychology, this study investigates which factors that modulate worry and fear associated with the presence of ticks among livestock owners of sheep and/or cattle. Methods: Survey data from 775 livestock owners in Norway were analysed by hierarchical multiple regression analysis with an index of fear of tick-borne diseases among livestock as the outcome variable. Results: Twenty-nine per cent of the livestock owners reported worry and fear of tick-borne diseases among their livestock. The model explained 35% of the variance in worry and fear. There was a weak association between esti-mated incidences of tick-borne diseases in livestock and livestock owners'worry and fear. Whereas previous personal experience of ticks and tick-borne diseases in livestock, and the livestock owners' appraisals of the situation were more strongly associated with relatively stronger feelings of worry and fear. Conclusions: Livestock owners'worry and fear of tick-borne diseases in livestock can partly be understood as their appraisals of perceived personal relevance of the presence of ticks, its potential negative implications for their daily life at large, and what potential they have to cope by different strategies to adapt or adjust to the situation.
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| 6. |
- Mumme, Steffen, et al.
(författare)
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Wherever I may roam—Human activity alters movements of red deer (Cervus elaphus) and elk (Cervus canadensis) across two continents
- 2023
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Ingår i: Global Change Biology. - Chichester : Wiley-Blackwell Publishing Inc.. - 1354-1013 .- 1365-2486. ; 29:20, s. 5788-5801
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Tidskriftsartikel (refereegranskat)abstract
- Human activity and associated landscape modifications alter the movements of animals with consequences for populations and ecosystems worldwide. Species performing long-distance movements are thought to be particularly sensitive to human impact. Despite the increasing anthropogenic pressure, it remains challenging to understand and predict animals' responses to human activity. Here we address this knowledge gap using 1206 Global Positioning System movement trajectories of 815 individuals from 14 red deer (Cervus elaphus) and 14 elk (Cervus canadensis) populations spanning wide environmental gradients, namely the latitudinal range from the Alps to Scandinavia in Europe, and the Greater Yellowstone Ecosystem in North America. We measured individual-level movements relative to the environmental context, or movement expression, using the standardized metric Intensity of Use, reflecting both the directionality and extent of movements. We expected movement expression to be affected by resource (Normalized Difference Vegetation Index, NDVI) predictability and topography, but those factors to be superseded by human impact. Red deer and elk movement expression varied along a continuum, from highly segmented trajectories over relatively small areas (high intensity of use), to directed transitions through restricted corridors (low intensity of use). Human activity (Human Footprint Index, HFI) was the strongest driver of movement expression, with a steep increase in Intensity of Use as HFI increased, but only until a threshold was reached. After exceeding this level of impact, the Intensity of Use remained unchanged. These results indicate the overall sensitivity of Cervus movement expression to human activity and suggest a limitation of plastic responses under high human pressure, despite the species also occurring in human-dominated landscapes. Our work represents the first comparison of metric-based movement expression across widely distributed populations of a deer genus, contributing to the understanding and prediction of animals' responses to human activity. Global Change Biology© 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd.
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| 7. |
- Peters, Wibke, et al.
(författare)
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Large herbivore migration plasticity along environmental gradients in Europe : life-history traits modulate forage effects
- 2018
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Ingår i: Oikos. - Chichester : Wiley-Blackwell Publishing Inc.. - 0030-1299 .- 1600-0706. ; 128, s. 416-429
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Tidskriftsartikel (refereegranskat)abstract
- The most common framework under which ungulate migration is studied predicts that it is driven by spatio–temporal variation in plant phenology, yet other hypotheses may explain differences within and between species. To disentangle more complex patterns than those based on single species/ single populations, we quantified migration variability using two sympatric ungulate species differing in their foraging strategy, mating system and physiological constraints due to body size. We related observed variation to a set of hypotheses. We used GPS-collar data from 537 individuals in 10 roe Capreolus capreolus and 12 red deer Cervus elaphus populations spanning environmental gradients across Europe to assess variation in migration propensity, distance and timing. Using time-to-event models, we explored how the probability of migration varied in relation to sex, landscape (e.g. topography, forest cover) and temporally-varying environmental factors (e.g. plant green-up, snow cover). Migration propensity varied across study areas. Red deer were, on average, three times more migratory than roe deer (56% versus 18%). This relationship was mainly driven by red deer males which were twice as migratory as females (82% versus 38%). The probability of roe deer migration was similar between sexes. Roe deer (both sexes) migrated earliest in spring. While territorial male roe deer migrated last in autumn, male and female red deer migrated around the same time in autumn, likely due to their polygynous mating system. Plant productivity determined the onset of spring migration in both species, but if plant productivity on winter ranges was sufficiently high, roe deer were less likely to leave. In autumn, migration coincided with reduced plant productivity for both species. This relationship was stronger for red deer. Our results confirm that ungulate migration is influenced by plant phenology, but in a novel way, that these effects appear to be modulated by species-specific traits, especially mating strategies. © 2018 The Authors. Oikos © 2018 Nordic Society Oikos
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