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155 results for “large herbivores”
Data from: The greenscape shapes surfing of resource waves in a large migratory herbivore
The Green Wave Hypothesis posits that herbivore migration manifests in response to waves of spring green-up (i.e. green-wave surfing). Nonetheless, empirical support for the Green Wave Hypothesis is mixed, and a framework for understanding variation in surfing is lacking. In a population of migratory mule deer (Odocoileus hemionus), 31% surfed plant phenology in spring as well as a theoretically perfect surfer, and 98% surfed better than random. Green-wave surfing varied among individuals and was unrelated to age or energetic state. Instead, the greenscape, which we define as the order, rate and duration of green-up along migratory routes, was the primary factor influencing surfing. Our results indicate that migratory routes are more than a link between seasonal ranges, and they provide an important, but often overlooked, foraging habitat. In addition, the spatiotemporal configuration of forage resources that propagate along migratory routes shape animal movement and presumably, energy gains during migration.
Data for: Horizontal viewsheds of large herbivores as a function of woodland structure
<p>This dataset contains values of tree stem density per hectare of different size classes (Sapling: > 0.3m, < 1.3m height, Small stem: >=1.3m height, < 10cm DBH, Medium stem: 10-20cm DBH, Large: 21-30cm DBH, Very large: >=31cm DBH), Viewshed Coefficient values (vc), Leaf Area Index (LAI) values for 0.75 - 1.5m above the ground and average percentage cover of bramble (<em>Rubus frutocisus agg.</em>). These data have come from 71 circular 15m-radius sampling plots (four-character codes in plotID column across ten woodland sites (three-character codes in site column). </p> <p>The "raw_data" tab contains the untransformed, unscaled raw data. The "transformed_scaled_data" tab contains the transformed, scaled data that were used in the modelling approach in the associated manuscript.</p>
Data from: Disparate home range dynamics reflect nutritional inadequacies on summer range for a large herbivore
<p>The spatial distribution of animals has consequences for nutrition, predator-prey dynamics, spread of diseases, and population dynamics in general. Animals must establish a home range to secure adequate resources to fuel their energetic needs. Home ranges, therefore, are temporally and spatially dynamic given the changing requirements of an animal and the availability of resources on the landscape. We used data from two populations of bighorn sheep with contrasting population dynamics following pneumonia epizootics and different habitat quality on their summer range to test the hypothesis that the distribution and size of home ranges are influenced by environmental conditions and reproductive status. We used a combination of data from 768 vegetation transects and remotely sensed metrics to index forage quality of consecutive biweekly home ranges for 27 bighorn sheep, June–August 2019–2021. There were population differences in space use that were consistent with resource limitations in the population declining in abundance. Animals in both populations increased the area of their space use through the summer in association with declining forage quality indexed by plant phenology. Furthermore, animals in the Whiskey Mountain population without live offspring used areas more than twice the size of animals with offspring, whereas there were no differences in the area of space use between animals with and without offspring in Jackson. We demonstrated that limitations young offspring impose on space use of a mother may have consequences for animals living where larger home ranges are needed to secure adequate resources—sheep in Whiskey Mountain had to travel 1,000 m from escape terrain to access the same amount of biomass that the Jackson sheep could access directly adjacent to escape terrain. Forage quality and availability influence movement and home range dynamics. In the presence of disease, movement and home range dynamics may influence pathogen transmission and persistence. Thus, forage availability may play an indirect role in population dynamics in the presence of disease, which is another line of evidence for how environmental and nutritional conditions may influence population dynamics of populations coping with disease.</p>
Ecological consequences of large herbivore exclusion in an African savanna: 12 years of data from the UHURU experiment
<p>Diverse communities of large mammalian herbivores (LMH), once widespread, are now rare. LMH exert strong direct and indirect effects on community structure and ecosystem functions, and measuring these effects is important for testing ecological theory and for understanding past, current, and future environmental change. This in turn requires long-term experimental manipulations, owing to the slow and often nonlinear responses of populations and assemblages to LMH removal. Moreover, the effects of particular species or body-size classes within diverse LMH guilds are difficult to pinpoint, and the magnitude and even direction of these effects often depends on environmental context. Since 2008, we have maintained the Ungulate Herbivory Under Rainfall Uncertainty (UHURU) experiment, a series of size-selective LMH exclosures replicated across a rainfall/productivity gradient in a semi-arid Kenyan savanna. The goals of the UHURU experiment are to measure the effects of removing successively smaller size classes of LMH (mimicking the process of size-biased extirpation) and to establish how these effects are shaped by spatial and temporal variation in rainfall. The UHURU experiment comprises three LMH-exclusion treatments and an unfenced control, applied to 9 randomized blocks of contiguous 1-ha plots (n = 36). The fenced treatments are: "MEGA" (exclusion of megaherbivores, elephant and giraffe); "MESO" (exclusion of herbivores ≥40 kg); and "TOTAL" (exclusion of herbivores ≥5 kg). Each block is replicated three times at three sites across the 20-km rainfall gradient, which has fluctuated over the course of the experiment. The first five years of data were published previously (Ecological Archives E095-064) and have been used in numerous studies. Since that publication, we have (a) continued to collect data following the original protocols, (b) improved the taxonomic resolution and accuracy of plant and small-mammal identifications, and (c) begun collecting several new data sets. Here, we present updated and extended raw data from the first 12 years of the UHURU experiment (2008–2019). Data include daily rainfall data throughout the experiment; annual surveys of understory plant communities; annual censuses of woody-plant communities; annual measurements of individually tagged woody plants; monthly monitoring of flowering and fruiting phenology; every-other-month small-mammal mark-recapture data; and quarterly large-mammal dung surveys.</p>
Data from: Large herbivores trigger spatiotemporal changes in forest plant diversity
<p class="MsoNormal"><span>Large herbivores can exert top-down control on terrestrial plant communities, but the magnitude, direction, and scale-dependency of their impacts remain equivocal, especially in temperate and boreal forests, where multiple disturbances often interact. Using a unique, long-term and replicated landscape experiment, we assessed the influence of a high density of white-tailed deer (</span><em><span>Odocoileus virginianus</span></em><span>) on the spatiotemporal dynamics of diversity, composition, and successional trajectories of understorey plant assemblages in recently logged boreal forests. This experiment provided a rare opportunity to test </span><span>whether deer herbivory represents a direct filter on plant communities or if it mainly acts to suppress dominant plants which, in turn, release other plant species from strong negative plant-plant interactions. These two hypotheses make different predictions about changes in community composition, alpha and beta diversity in different</span><span> vegetation layers and at different spatial scales. Our results showed that deer had strong effects on plant community composition and successional trajectories, but the resulting impacts on plant alpha and beta diversity patterns were markedly scale-dependent in both time and space. Responses of tree and non-tree vegetation layers were strongly asymmetric. Deer acted both as a direct filter and as a suppressor of dominant plant species during early forest succession, but the magnitude of both processes was specific to tree and non-tree vegetation layers. Although our data supported the </span><span>ungulate-driven </span><span>homogenization hypothesis, </span><span>compositional shifts and changes of alpha diversity were poor predictors of beta diversity loss.</span><span> Our findings underscore the importance of long-term studies in revealing non-linear temporal community trends, and they challenge managers to prioritize particular community properties and scales of interest, given contrasting trends of composition, alpha, and beta diversity across spatial scales.</span></p>
The generality of cryptic dietary niche differences in diverse large-herbivore assemblages
<p>Ecological niche differences are necessary for stable species coexistence but are often difficult to discern. Models of dietary niche differentiation in large mammalian herbivores invoke the quality, quantity, and spatiotemporal distribution of plant tissues and growth-forms but are agnostic towards food-plant species identity. Empirical support for these models is variable, suggesting that additional mechanisms of resource partitioning may be important in sustaining large-herbivore diversity in African savannas. We used DNA metabarcoding to conduct a taxonomically explicit analysis of large-herbivore diets across southeastern Africa, analyzing ~4,000 fecal samples of 30 species from 10 sites in 7 countries over 6 years. We detected 893 food-plant taxa from 124 families, but just two families—grasses and legumes—accounted for the majority of herbivore diets. Nonetheless, herbivore species almost invariably partitioned food-plant taxa; diet composition differed significantly in 97% of pairwise comparisons between sympatric species, and dissimilarity was pronounced even between the strictest grazers (grass eaters), strictest browsers (non-grass eaters), and closest relatives at each site. Niche differentiation was weakest in an ecosystem recovering from catastrophic defaunation, indicating that food-plant partitioning is driven by species interactions, and stronger at low rainfall, as expected if interspecific competition is a predominant driver. Diets differed more between browsers than grazers, which predictably shaped community organization: grazer-dominated trophic networks had higher nestedness and lower modularity. That dietary differentiation is structured along taxonomic lines complements prior work on how herbivores partition plant parts and patches and suggests that common mechanisms govern herbivore coexistence and community assembly in savannas.</p>
Niche overlap between two large herbivores across landscape variability using dietary eDNA metabarcoding: Raw sequences of European bison and red deer – Bialowieza
<p><span>Understanding the trophic ecology of herbivore species is key to assess their environmental requirements and to improve management policies, but measuring their trophic interactions remains challenging. Among the methods available, quantifying the plant composition of a species' diet provides a detailed picture of how species exploit the resources in their environment and their associated niche overlap. Yet, most studies focusing on herbivore trophic ecology ignore the influence that landscape variability may have. Here, we studied how landscape variability influences trophic interactions through niche partitioning. We used eDNA metabarcoding to quantify the diet composition of two large herbivores of the Bialowieza Forest, red deer (<em>Cervus elaphus</em>) and European bison (<em>Bison bonasus</em>, hereafter referred to as bison) to investigate how increasing habitat quality and predation risk in their environment influence their diet composition and niche partitioning. We found red deer to have an overall greater diet variability and lower niche overlap within species compared to bison. Moreover, our findings indicate herbivore interactions are non-homogeneous across the landscape. Higher habitat quality was associated with higher niche overlap only within bison. We also detected an increase in niche overlap with increasing predation risk within red deer, indicating they modify their diet choice as a reaction to wolf predation risk. This study provides evidence of eDNA dietary metabarcoding as a useful tool for wildlife management to assess the status of species in an ecosystem based on known environmental factors. We suggest future studies to integrate the environments' variability when studying trophic ecology of herbivores to capture the whole extent of species interaction in order to improve conservation and management guidelines. </span></p>
Ecosystem-wide responses to fire and large mammal herbivores in an African savanna
<p>Fire and large mammal herbivores (LMH) are the principal top-down forces maintaining savanna structure. Nonetheless, experiments designed to investigate interactions between fire and LMH are rare in savannas, and relationships between environmental variation and biodiversity in the context of fire and LMH are poorly understood. This study addresses these gaps by manipulating the presence of LMH and early and late dry season fires in a tropical African savanna. In addition, this work simultaneously explores environmental variables including soil and foliar quality, vegetation cover, and nearby water sources to more holistically describe factors affecting savanna functioning and biodiversity. </p> <p>After one year of experimental treatments, changes in vegetation were already apparent. Shrub abundance and richness and grass richness were higher in the absence of LMH, while grass biomass increased three-fold in burned plots as compared to unburned plots. Foliar nutrients tended to increase in open plots, while phenolics decreased. Amphibian abundance decreased with early burns and was higher with LMH. In contrast, small mammal abundance and richness increased without LMH and with time since fire. Richness and foraging of LMH were highest after late burns.</p> <p>These results demonstrate ecosystem-wide effects of LMH, illustrating the importance of considering multiple taxa when designing fire management programs. For example, burning negatively affected amphibians and small mammals and changed vegetation at the same time it increased LMH foraging. In the long-term, this experiment will shed light on interacting effects of fire and LMH on savanna biodiversity and function. </p>
Interacting effects of surface water and temperature on wild and domestic large herbivore aggregations and contact rates
<p>Earth's climate is rapidly changing, bringing forth questions of how domestic and wild animals will alter their behavior in response to increasing temperatures and dryland expansion. Dwindling water availability will likely impact animal behavior and water foraging, potentially increasing animal aggregations and interspecific contacts. These interspecific contacts are especially important for competition, predation, and disease transmission among wildlife and domestic animals.</p> <p>In this study, we analyzed interspecific wildlife and cattle contacts using two years of camera trap data at an experimental water manipulation site at a conservancy in central Kenya.</p> <p>We found that on average, the hourly probability of any interspecific contact was approximately 3.4 times higher at water sources versus drained water sources, and 18 times higher than surrounding matrix areas, and that this relationship was amplified by dry and hot conditions.</p> <p>Species-specific analyses revealed variation in the magnitude of responses across wildlife and domestic cattle, although all animals had approximately 2-3 times higher interspecific contact probability with other species at water in hot conditions versus other conditions. Notably, we observed the largest behavioral changes for relatively water-independent species, such as giraffe, which had 3.6 times higher interspecific contact probability at water sources in hot versus other conditions.</p> <p><em>Synthesis and applications:</em> These findings show how elevated temperatures that will become increasingly common with future climate changes can increase interspecific contacts around critical water resources. In mixed wildlife-livestock systems, maintaining wildlife-only water sources may be a practical management tool to mitigate human-wildlife conflict and disease transmission at this interface, especially during dry and hot conditions.</p>
Fig. 6 in Large Herbivore Abundance, Distribution And Winter Pasture Quality In Two Game Farms In North Kazakhstan
Fig. 6. Siberian roe deer wintering concentration places in "Zerenda" game farm.
Fig. 1 in Large Herbivore Abundance, Distribution And Winter Pasture Quality In Two Game Farms In North Kazakhstan
Fig. 1. Moose wintering concentration places in "Bulandy" game farm.
Fig.4 in Large Herbivore Abundance, Distribution And Winter Pasture Quality In Two Game Farms In North Kazakhstan
Fig.4. Moose wintering concentration places in "Zerenda" game farm.
The burden of size and growth for the juveniles of large mammalian herbivores: structural and functional constraints in the feeding biology of juveniles relative to adults in red kangaroos, Osphranter rufus
<p>Juvenile mammals in their post weaning developmental stages face many challenges in transitioning to adulthood. Among large grazing species such as ruminant bovids and cervids an overarching challenge is acquiring and processing sufficient nutrients to survive and grow, with a gut that may not yet be fully developed. Marsupial kangaroos of Australia face similar challenges; they also digest vegetation by fermentation in a large foregut. In red kangaroos, Osphranter rufus (= Macropus rufus), the dominant species of Australia's arid interior, females may breed continuously; however, juvenile recruitment to the adult population is irregular and coincident with sporadic rainfall. As compared with adult females the nutritional requirements of juvenile O. rufus are high in relation to their body mass (BM), largely due to the cost of their rapid growth. We examined processes that juveniles have in their morphology, physiology and behaviours to meet their elevated nutritional needs, by comparing recently weaned juveniles of both sexes and adult female O. rufus in their desert habitat. Features studied include relative body sizes, relative dimensions and capacities of principal gut regions, the foregut, small intestine, caecum and large intestine with rectum. Also examined were digesta attributes and rates of digesta excretion. Additionally, the rates of change in skull parameters and dental characteristics to maturity were assessed. Field determinations of diet choice were made for both age classes. In juveniles the content masses of major gut structures were related to body mass (BM), as were those of adult females, i. e. ~BM1.0. In both age classes the digesta mass of the foreguts exceeded 75 % of the total digesta mass. Diets of both juvenile and adult O. rufus largely focused on grasses. Juveniles had higher rates of digesta excretion while foraging than adults. In addition, the foregut contents in juveniles occupies proportionally less of the total gut than in adult females. Together, the higher excretion rate and smaller relative foregut of juveniles suggests that they necessarily focus on forage that can be rapidly digested, such as young, green grasses or herbage. Comparison of the skulls of juveniles and adults revealed how this harvest can occur. Relative to BM juveniles had skulls of larger volume than adults. Additionally, during growth the skull lengthens proportionally faster than increasing. By weaning the dimensions of the incisor bite of juveniles neared those of adult females. The area of wear on premolars/molars increased only slowly relative to the development of incisors, further pointing to juveniles selecting more digestible forage than adults. The intermittent availability of such forage, principally young grasses, appears key to the significant recruitment into the O. rufus population in their arid habitat.</p>
Large herbivores suppress liana infestation in an African savanna
<p>African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages—declining wildlife populations and their displacement by livestock—may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, <i>Cynanchum viminale </i>(Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 years (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-year-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana-tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.</p>
Large wild herbivores slow down the rapid decline of plant diversity in a tropical forest biodiversity hotspot
<p>1. The UN declaration of the Decade of Ecosystem Restoration 2021-2030 emphasizes the need for effective measures to restore ecosystems and safeguard biodiversity. Large herbivores regulate many ecosystem processes and functions, yet their potential as a nature-based solution to buffer against long-term temporal declines in biodiversity associated to global change and restore diversity in secondary forests remains unknown.</p> <p>2. By means of an exclusion experiment, we tested experimentally the buffering effects of large wild herbivores to avert against long-term biodiversity collapse in old-growth and secondary tropical forests in the Atlantic Forest of Brazil where sapling abundance and species richness declined circa 20% over the course of 10 years. The experiment comprised 50 large herbivore exclosure-open control plot pairs (25 at the old-growth forest and 25 at the secondary forest), where 2m2 were monitored in every plot during a 10-year period.</p> <p>3. Large herbivores were able to decelerate diversity declines and compositional change in the species-rich old-growth forest, but only decelerated compositional change in the secondary forest. In contrast, declines in species richness and abundance were unaffected by large herbivores on either forest.</p> <p>4. The buffering effects of large herbivores were strongly non-linear and contingent on the initial level of diversity at the patch scale: highly diverse communities suffered the strongest collapse in the absence of large herbivores. Thus, larger buffering effects of large herbivores on the old growth forest are the logical consequence of large herbivores buffering the many high diversity plant communities found in this forest. Conversely, as the secondary forest held fewer high diversity patches, buffering effects on the secondary forest were weak.</p> <p>5. Synthesis and applications: Our study indicates that large herbivores have moderate yet critical effects on slowing down community change and diversity loss of highly diverse plant communities, thus suggesting that the conservation of (and potentially trophic rewilding with) large herbivores is a fundamental nature-based solution for averting the global collapse of the strongholds of biodiversity. Its buffering effects on biodiversity loss operate at very small spatial scales, are likely contingent on successional stage, and most effective in old-growth or high diversity secondary forests.</p>
Nimble code and dataset for: Estimating true density in large, alpine herbivores using Google Earth imagery
<p>This nimble code will estimate elk density from the count data (DO_data_list.RData) and covariates (DO_constants_list.RData). Data and covariates include: a 'y' matrix of double observer counts with 3315 rows (1 for each 250 m square plot) and 3 columns for the observer 1's exclusive counts, observer 2's exclusive counts, and the count of elk detected by both observers. The double-observe protocol was only employed in 372 random cells. 'n' is a vector of total counts – the total number of uniquely detected elk in each plot. 'obs1tot' is a vector of the total count of elk by just observer 1, who counted elk in all 3315 cells. There are two dummy indicator variables that are all 1's ('obs1constraint' and 'obs2constraint') to constrain unobserved but estimated counts to sum to expected totals. For example, observer 1 was the only observer in 2943 plots. This single count would be the equivalent of the sum of the exclusive observer 1 counts and the joint observer 1 and 2 counts in a double-observer protocol. Additionally, the sum of observer 2s exclusive counts and observer 1's total counts must equal the total count of unique individuals in a cell. The covariates 'meadow' and 'deadfall' are the additive log-ratio transformations of the proportion of open meadow and burned forest, respectively, in each 250-m plot. The 'nonforest' covariate is the number of hectares in each plot that was not conifer forest. 'M' is the total number of plots. 'firstsearch' is an indicator variable, indicating which plots were part of the first search area in the alpine >2750 m above sea level. 'domethod' is an indicator variable, indicating which plots were searched using the double-observer protocol. </p>
Parasites as ecosystem modulators: Foliar pathogens suppress top-down effects of large herbivores
<p><span>Parasites can catalyze or inhibit interactions between their hosts and other species, but the ecosystem-level effects of such interaction modifications are poorly understood. We conducted a large-scale field experiment in temperate grasslands of northeastern China to understand how foliar fungal pathogens (e.g., rusts and leaf</span><span> spot</span><span>s</span><span>) influenced top-down effects of large herbivores (cattle; <em>Bos</em> <em>taurus</em>) on plant diversity and productivity. In the absence of foliar pathogens, cattle grazing strongly suppressed biomass of the dominant grass, <em>Leymus</em> <em>chinensis</em>, (↓56%), generating competitive release that significantly increased plant species richness (↑75%) and evenness (↑15%). In the absence of grazing, pathogen attack on <em>L. chinensis</em> had no measurable effect on host biomass. However, pathogen infection greatly weakened top-down effects of herbivory by inhibiting cattle grazing on <em>L. chinensis</em> and negating grazing effects on plant biomass and species richness. Mechanistically, foliar pathogens were linked to increased alkaloid (↑45%) and reduced nitrogen levels (↓19%) in leaf tissue that appeared to deter cattle grazing on<em> L. chinensis</em>. Our results demonstrate that foliar pathogens can suppress top-down effects of large herbivores on grassland community structure and function by modifying the strength of its host's interactions with the dominant consumer. We propose that parasites may function primarily as modulators of ecosystem function when their direct effects on host density (often dampened by evolution) are overshadowed by influences on host traits that modify host interactions with strong competitors, herbivores, or predators.</span></p>
Age specific impacts of vegetation functional traits on gastro-intestinal nematode parasite burdens in a large herbivore
<ol> <li>Gastro-intestinal nematode (GIN) parasites play an important role in the ecological dynamics of many animal populations. Recent studies suggest fine-scale spatial variation in GIN infection dynamics is important in wildlife systems, but the environmental drivers underlying this variation remain poorly understood.</li> <li>We used data from over two decades of GIN parasite egg counts, host space use, and spatial vegetation data from a long-term study of Soay sheep on St Kilda to test how spatial autocorrelation and vegetation in an individual's home range predict parasite burden across three age groups. We developed a novel approach to quantify the plant functional traits present in a home range to describe the quality of vegetation present. </li> <li>Effects of space and vegetation varied between age classes. In immature lambs, strongyle parasite faecal egg counts (FEC) were spatially structured, being highest in the north and south of our study area. Independent of host body weight and spatial autocorrelation, plant functional traits predicted parasite egg counts. Higher egg counts were associated with more digestible and preferred plant functional traits, suggesting the association could be driven by host density and habitat preference.</li> <li>In contrast, we found no evidence that parasite FEC were related to plant functional traits in the host home range in yearlings or adult sheep. Adult FEC were spatially structured, with highest burdens in the north-east of our study area, while yearling FEC showed no evidence of spatial structuring.</li> <li>Our findings support the importance of fine-scale environmental variation for wildlife disease ecology and provide new evidence that such effects may vary across demographic groups within a population. Parasite burdens in immature individuals appear more readily influenced by fine-scale spatial variation in the environment, highlighting the importance of such heterogeneity for our understanding of wildlife epidemiology and health.</li> </ol>
Large mammalian herbivores affect arthropod food webs via changes in vegetation characteristics and microclimate
<ol> <li>Large mammalian herbivores are vital components of terrestrial ecosystems, influencing the plants they feed on, but also serving as ecosystem engineers that impact the occurrence and survival of many other organisms. Arthropods are the most abundant and diverse animal group on earth, filling all trophic levels in food webs and facilitating essential ecosystem services. However, the impacts of large herbivores on arthropod communities and the mechanisms via which these impacts are mediated are not fully understood. </li> <li>Here, we experimentally separated the mechanistic pathways whereby large herbivores affect arthropod food webs using a 24-year manipulative multi-site field experiment in the Netherlands. We analyzed the abundance, biomass, and community composition of arthropods in the plant canopy and on the soil surface, both in grazed sites or sites where large herbivores were excluded.</li> <li>We found that the presence of large herbivores resulted in considerable differences in vegetation properties and microclimate which influenced the abundance and biomass of arthropods to varying trophic levels. Large herbivore grazing enhanced the overall abundance and biomass of arthropod herbivores, pollinators, omnivores, and soil-dwelling predators, but reduced that of detritivores, scavengers, parasitoids, and canopy predators. Structural equation models revealed that different trophic groups are affected by grazing via different pathways. Specially, large herbivores facilitated herbivores via increasing plant quality and enhanced ground-dwelling predators via increasing plant diversity. In contrast, plant-dwelling predators were suppressed via decreased plant quantity, and parasitoids were mainly affected by changes in microclimate conditions. </li> <li> <em>Synthesis</em>. Our results show that large mammalian herbivores play a significant role in shaping grassland arthropod food webs and that these impacts were independently mediated by multiple aspects of vegetation properties, i.e., physical structure, plant diversity, standing crop biomass, and leaf nutrient content. Arthropods of different trophic groups responded differently to the large herbivores, and these functional group-specific responses in turn may have strong cascading effects on numerous ecosystem services.</li> </ol>
Data from: Contrasting impacts of short- and long-term large herbivore exclusion on understory net CO2 exchange in a boreal forest
<p>Across boreal forests, trees are the main living biomass carbon (C) stock, but the understory vegetation can contribute significantly to the C cycling and net forest carbon dioxide (CO<sub>2</sub>) balance. The patchy understory vegetation which consists of sunlit (i.e., lichen-like) and shaded habitats (i.e., dwarf shrub-like) is often altered by ungulate grazers. Grazers may influence understory CO<sub>2</sub> exchange, and consequently, the forest CO<sub>2</sub> balance. Grazing affects differently the biomass of slow growing lichens compared to the faster growing mosses and dwarf shrubs, and therefore the effects of grazing on CO<sub>2</sub> exchange in the patchy understory vegetation could vary temporally. We studied how excluding grazing for short- and long-term affects the CO<sub>2</sub> exchange and vegetation biomass in the understory of an oligotrophic Scots pine forest. We measured growing season (2019, 2020) CO<sub>2</sub> exchange across sunlit and shaded habitats inside fences that had excluded large grazers for 0–1 and 25–26 years and in the adjacent grazed area. In addition, we measured the height of understory vegetation. We found that short-term grazer exclusion increased ecosystem CO<sub>2</sub> source fluxes only in the shaded habitats. However, long-term exclusion of grazing decreased CO<sub>2</sub> net release regardless of the habitat type. Furthermore, grazer exclusion increased moss depth immediately which coincided with an abrupt intensification of CO<sub>2</sub> net release. Considering the impacts of grazing over both short- and long-term may help to forecast C fluxes more accurately which may be relevant for informed climate solutions regionally and even on a larger scale.</p>
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Allen Brain Atlas
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Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
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OpenNeuro
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