| 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. |
- Jarnemo, Anders, 1968-, et al.
(författare)
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Home range sizes of red deer in relation to habitat composition : a review and implications for management in Sweden
- 2023
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Ingår i: European Journal of Wildlife Research. - Heidelberg : Springer. - 1612-4642 .- 1439-0574. ; 69:5
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about deer spatial use is essential for damage mitigation, conservation, and harvest management. We assess annual and seasonal home range sizes in relation to habitat composition for red deer (Cervus elaphus) in Sweden, using GPS-data from two regions with different management systems. We compare our findings with reviewed data on red deer home range sizes in Europe. Annual and seasonal home ranges during calving, hunt, and winter-spring, decreased with increasing proportion forest. Female annual home ranges in a mixed agricultural-forest landscape were three times larger than in a forest-dominated landscape. Core areas (50% Kernels) were approximately 1/5 of the full annual and seasonal home ranges (95% Kernels) regardless of habitat composition. Home range size in the forest-dominated landscape showed little inter-seasonal variation. In the agricultural-forest landscape, home ranges were larger during calving, hunt, and winter-spring compared to summer and rut. In the forest-dominated landscape, management areas are large enough to cover female spatial use. In the agricultural-forest landscape, female spatial use covers several license units. Here, the coordinated license system is needed to reach trade-offs between goals of conservation, game management, and damage mitigation. Males had in general larger home ranges than females, and the majority of the males also made a seasonal migration to and from the rutting areas. The license system area in the agricultural-forest landscape is large enough to manage migrating males. In the forest landscape, a coordination of several management areas is needed to encompass male migrations. We conclude that management needs to adapt to deer spatial use in different types of landscapes to reach set goals. © 2023, The Author(s).
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| 3. |
- Jarnemo, Anders, et al.
(författare)
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The proximity of rapeseed fields influences levels of forest damage by red deer
- 2022
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Ingår i: Ecological Solutions and Evidence. - Chichester, West Sussex : Blackwell Publishing Ltd.. - 2688-8319. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Deer can show transitional use between agricultural fields and forests for foraging and shelter. Such transitional use may affect forest damage as nutrient balancing theory suggests that if deer ingest large amounts of nutrient-rich food, complementary browse, such as bark, may be required to balance the diet. We investigated the relationship between the level of red deer Cervus elaphus bark-stripping damage in 68 Norway spruce Picea abies stands and the presence of rapeseed Brassica napus fields – an energy-rich crop preferred by red deer – in the surroundings, hypothesizing that damage increases with decreasing distance to rapeseed fields. We also considered other potentially influencing factors, such as supplemental feeding, alternative forage availability, and deer use of spruce stands as indexed by a pellet group count. Spruce stands closer to rapeseed had a significantly higher proportion of damaged stems. The increased level of bark-stripping damage was not explained by a higher stand use of deer closer to rapeseed fields, indicating that deer increase their consumption of bark in order to balance their diet. Similarly, spruce stands closer to supplemental feeding stations had significantly higher damage levels. In line with earlier findings, damage levels were negatively related to the amount of available browse in the forest. This emphasizes the importance of alternative forage for reducing the damage risk in forest plantations. Our study shows that the availability of fields with nutrient-rich food, such as rapeseed, as well as supplemental feeding needs to be considered when predicting the level of forest damage. With a high availability of nutrient-rich food in the vicinity of forest stands, a higher damage level can be expected and counteractions could be taken such as increased disturbance, harvest or changed choice of both crop and supplemental feed types. These actions may also be combined with a push–pull strategy where the deer are steered to disturbance-free zones insensitive to damage and with alternative forage. The importance of alternative forage availability on damage levels highlights the necessity for managers to actively promote tree and shrub forage within and around their production stands. © 2022 The Authors. Ecological Solutions and Evidence published by John Wiley & Sons Ltd on behalf of British Ecological Society.
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| 4. |
- Juvany, Laura, et al.
(författare)
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From simple metrics to cervid forage : Improving predictions of ericaceous shrub biomass
- 2023
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Ingår i: Forest Ecology and Management. - Amsterdam : Elsevier. - 0378-1127 .- 1872-7042. ; 544
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Tidskriftsartikel (refereegranskat)abstract
- Common understory vegetation species such as the ericaceous shrubs bilberry (Vaccinium myrtillus), cowberry (V. vitis-idaea) and heather (Calluna vulgaris), are key forage plant species for moose and other large herbivores, as well as fulfilling many additional ecosystem functions and services. Here we developed models to predict above-ground biomass of these ericaceous species in coniferous forests, using data on their percentage cover, height, and different stand characteristics. We also built models to understand how the aforementioned variables affect the proportion of the shrubs commonly utilized as forage by large herbivores. We found that the percentage cover of shrubs was the most important explanatory variable when predicting above-ground biomass, explaining 51%, 47% and 71% of the variation (marginal R2) in bilberry, cowberry and heather biomass, respectively. By adding ramet height to the model with percentage cover, the variation explained increased to 77% for bilberry, 75% for cowberry and 87% for heather. The best outcome for candidate models was obtained by adding stand site index and spruce basal area to the model, improving the variation explained in bilberry to 83%, to 81% for cowberry, and 91% for heather. When modelling the proportion of the shrubs commonly utilized as forage by large herbivores, stand site index and spruce basal area often played important roles. Some of the best fitting models for forage biomass explained 51% of the variation in bilberry, 59% in cowberry and 30% in heather. Site location did not have a major role in improving the variability explained in either type of model, which indicated the applicability of the models regardless of study location. Our models therefore have a high potential to be implemented in forestry decision support systems. Their inclusion should provide better large-scale estimations of forage resources, aiding forest management, and thereby taking an important step forward to determine the ecosystem carrying capacity of large herbivores. © 2023 The Author(s)
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| 5. |
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| 6. |
- Montras Janer, Teresa, et al.
(författare)
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Samband mellan förekomst av stora betande fåglar och skador på gröda
- 2020
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Ingår i: Vilt och tamt fakta: ett faktablad från Viltskadecenter och SLU.
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Annan publikation (populärvet., debatt m.m.)abstract
- Antalet gäss, sångsvanar och tranor i Sverige och övriga Europa har ökat de senaste årtiondena.Fåglarna väljer gärna att beta på fält med växande grödor och kan därmed orsaka skördeförluster.I den här studien undersökte vi hur sambandet mellan antalet fåglar och skadenivåer ser ut över tid i Sverige.Skadorna ökar med antalet fåglar, men även andra faktorer (till exempel väder) påverkar skadegraden. Därför är det mycket svårt att förutsäga hur stora skadorna kommer att bli från år till år, även om man har kunskap om antalet fåglar.En reducering av antalet fåglar kan vara ett sätt att minska skadorna på lång sikt, men man kan inte förvänta sig en direkt respons.
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| 7. |
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| 8. |
- 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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| 9. |
- Månsson, Johan, et al.
(författare)
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Habitat and crop selection by red deer in two different landscape types
- 2021
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Ingår i: Agriculture, Ecosystems & Environment. - Amsterdam : Elsevier. - 0167-8809 .- 1873-2305. ; 318
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Tidskriftsartikel (refereegranskat)abstract
- Crop raiding ungulates can cause costly yield losses and conflicts between agriculture, game management, and conservation. It is therefore crucial to know how, where, and when ungulates use different habitats and crops. In this study we used resource selection functions and GPS-tagged red deer Cervus elaphus (n = 38) in two different study areas (North – mainly forested land and South – mainly arable land), to investigate how red deer use arable land and different crop types in relation to availability and distance to forest cover in Sweden. Our study shows a transitional use of arable land and forests by red deer. Red deer spend on average 45% and 21% of their time in arable land in South and North respectively. In the North, arable land was selected while forest and wetlands were selected in the South. The selection of different crops also differed between the two study areas, for example rapeseed was highly selected during both seasons in South while it was used to a lower degree in relation to its availability in the North. In both study areas the probability of red deer presence on the agricultural fields decreased with distance to forest. The significant use of arable land and unharvested crops by the increasing red deer population in Sweden highlights a risk for crop damage that may need further consideration for farming practices as well as for damage and wildlife management. In our case damage mitigation should focus on rapeseed in the South, whereas there is a less clear pattern of selection among growing crops in the North. The differences in habitat and crop selection between the two areas also highlights the need of knowledge about red deer habitat selection at a regional level to be able to adapt damage mitigation and wildlife management strategies accordingly. Moreover, the transitional use of arable land and forests by red deer in mixed landscapes may imply that consumption of certain crops can affect browsing patterns and damage levels within forests and vice versa, that may have implication for both agriculture and forestry and calls for future studies. © 2021
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| 10. |
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