Hyaenas play unique ecosystem role by recycling key nutrients in bones

No abstract available.DATA AVAILABILITY STATEMENT : The data generated and analysed during this study is available via the Figshare repository: https://figshare.com/s/0e351eea70dd218f7ccf.Tswalu Foundationhttp://www.wileyonlinelibrary.com/journal/ajehj2022Mammal Research InstituteZoology and EntomologyPlant Production and Soil Scienc

Diet breadth, coexistence and rarity in bumblebees

Factors that determine the relative abundance of bumblebee species remain poorly understood, rendering management of rare and declining species difficult. Studies of bumblebee communities in the Americas suggest that there are strong competitive interactions between species with similar length tongues, and that this competition determines the relative abundance of species. In contrast, in Europe it is common to observe several short-tongued species coexisting with little or no evidence for competition shaping community structure. In this study we examine patterns of abundance and distribution in one of the most diverse bumblebee communities in Europe, found in the mountains of southern Poland. We quantify forage use when collecting nectar and pollen for 23 bumblebee species, and examine patterns of co-occurrence and niche overlap to determine whether there is evidence for inter-specific competition. We also test whether rarity can be explained by diet breadth. Up to 16 species were found coexisting within single sites, with species richness peaking in mountain pasture at ~1000m altitude. Results concur with previous studies indicating that the majority of pollen collected by bumblebees is from Fabaceae, but that some bee species (e.g. B. ruderatus) are much more heavily dependent on Fabaceae than others (e.g. B. lucorum). Those species that forage primarily on Fabaceae tended to have long tongues. In common with studies in the UK, diet breadth was correlated with abundance: rarer species tended to visit fewer flower species, after correcting for differences in sample size. No evidence was found for similarity in tongue length or dietary overlap influencing the likelihood of co-occurrence of species. However, the most abundant species (which co-occurred at most sites) occupied distinct dietary niche space. While species with tongues of similar length tended, overall, to have higher dietary niche overlap, among the group of abundant short-tongued species that commonly co-occurred there was marked dietary differentiation which may explain their coexistence

Annual flower strips support pollinators and potentially enhance red clover seed yield

Ecological intensification provides opportunity to increase agricultural productivity while minimizing negative environmental impacts, by supporting ecosystem services such as crop pollination and biological pest control. For this we need to develop targeted management solutions that provide critical resources to service-providing organisms at the right time and place. We tested whether annual strips of early flowering phacelia Phacelia tanacetifolia support pollinators and natural enemies of seed weevils Protapion spp., by attracting and offering nectar and pollen before the crop flowers. This was expected to increase yield of red clover Trifolium pratense seed. We monitored insect pollinators, pests, natural enemies and seed yields in a total of 50 clover fields along a landscape heterogeneity gradient, over 2 years and across two regions in southern Sweden. About half of the fields were sown with flower strips of 125-2,000 m2. The clover fields were pollinated by 60% bumble bees Bombus spp. and 40% honey bees Apis mellifera. The clover seed yield was negatively associated with weevil density, but was unrelated to bee species richness and density. Flower strips enhanced bumble bees species richness in the clover fields, with the strongest influence in heterogeneous landscapes. There were few detectable differences between crop fields with and without flower strips. However, long-tongued bumble bees were redistributed toward field interiors and during phacelia bloom honey bees toward field edges. Clover seed yield also increased with increasing size of the flower strip. We conclude that annual flower strips of early flower resources can support bumble bee species richness and, if sufficiently large, possibly also increase crop yields. However, clover seed yield was mainly limited by weevil infestation, which was not influenced by the annual flower strips. A future goal should be to design targeted measures for pest control

Improved estimation of gut passage time considerably affects trait‐based dispersal models

1. Animals are important vectors for transporting seeds, nutrients and microbes across landscapes. However, models that quantify the magnitude of these ecosystem services across a broad range of taxa often rely on generalised mass-based scaling parameters for gut passage time. This relationship is weak and fundamentally breaks down when considering individual species, indicating that current models may incorrectly attribute or estimate the magnitude of dispersal. 2. We collated a large dataset of gut passage time for endothermic animals measured using undigested markers (n = 391 species). For each species, we compiled trait data, including body mass, morphology, gut physiology, diet and phylogeny. We then compared the ability of five statistical models (constant, generalised least squares, phylogenetic generalised least squares, general linear model and random forest) to estimate the time of first marker appearance (transit time; TT) and mean marker retention time (MRT) for particle and solute markers in mammals and birds separately. 3. For mammals, we found that the inclusion of additional traits appreciably reduced the median root-mean squared error across all markers in a leave-one-out cross validation. For birds, however, additional traits did not significantly improve our ability to predict gut passage time across markers. This may have occurred due to the smaller number of bird species included in our analysis or the absence of important explanatory factors such as differences in gastrointestinal morphology. 4. Using the MRTparticle random forest model from this study, we updated two trait-based dispersal models for seed and nutrient movement by mammals. The magnitude of dispersal in our updated predictions ranged from 66% to 176% of the original model formulation for different scenarios, highlighting the importance of gut passage time for dispersal models. Furthermore, the contribution by individual or groups of species was found sizeably altered in our updated models. 5. Future modelling studies of dispersal by mammals, for which empirical estimates of gut passage time are absent, will benefit from predicting gut passage time using statistical models that incorporate traits including animal morphology, diet and gut physiology

Large predators can mitigate nutrient losses associated with off-site removal of animals from a wildlife reserve

Please read abstract in the article.National Aeronautics and Space Administration, a Google Earth Engine research and the Royal Society Newton International Fellowship.http://wileyonlinelibrary.com/journal/jpehj2022Mammal Research InstitutePlant Production and Soil Scienc

Large predators can mitigate nutrient losses associated with off‐site removal of animals from a wildlife reserve

1. Animals concentrate key nutrients in their bodies. In fenced wildlife reserves where nutrient input and/or retention is low, the off-site removal of animals may constitute a significant loss of nutrients for the ecosystem. 2. Here we add wildlife capture and removal into the phosphorus (P) and calcium (Ca) budget for a 121,700 ha fenced game reserve located in the southern Kalahari. We then use faecal P concentrations from 11 mammal herbivores >10 kg as an indicator of potential nutrient stress in this system to investigate whether the implications of nutrient loss via off-site wildlife removal may be cause for concern. Finally, we assess the role of natural predation as a mechanism to minimise the need for wildlife removal and concomitant nutrient loss. 3. During the period 2009–2018, mean loss of P and Ca via wildlife removal was 2.9 and 6.2 kg km−2 year−1, respectively. This compares to 1.0 and 2.1 kg km−2 year−1 of P and Ca added via the provision of mineral licks. If it is assumed that natural fluxes of these elements are in steady state, then anthropogenic activities have resulted in a net deficit of 18.5 kg/km2 of P and 40.6 kg/km2 of Ca over the decade. 4. We found that dry season herbivore faecal P concentrations are close to or below a widely cited minimum threshold of 2,000 mg/kg, below which most vertebrates begin suffering growth and reproductive issues. Large animals were more likely to be under this threshold. Prolonged continuation of off-site wildlife removal may result in nutrient losses that can lead to long-term ecological degradation. Natural predation levels were, however, found sufficient to mitigate the need for wildlife removal and present a management strategy whereby herbivore populations can be regulated without a loss of nutrients. 5. Synthesis and applications. We find that the capture and permanent removal of large-bodied animals from wildlife reserves can be a significant cause of nutrient loss. Over time, in sites where nutrient input and/or retention is low, this may contribute to nutritional stress for remaining resident animals. Where possible, holistic management strategies that promote the retention of animals and carcasses within the reserve—such as the reintroduction of large carnivores—should be preferred

Megafauna decline have reduced pathogen dispersal which may have increased emergent infectious diseases

The Late Quaternary extinctions of megafauna (defined as animal species > 44.5 kg) reduced the dispersal of seeds and nutrients, and likely also microbes and parasites. Here we use body-mass based scaling and range maps for extinct and extant mammal species to show that these extinctions led to an almost seven-fold reduction in the movement of gut-transported microbes, such as Escherichia coli (3.3-0.5 km(2) d(-1)). Similarly, the extinctions led to a seven-fold reduction in the mean home ranges of vector-borne pathogens (7.8-1.1 km(2)). To understand the impact of this, we created an individual-based model where an order of magnitude decrease in home range increased maximum aggregated microbial mutations 4-fold after 20 000 yr. We hypothesize that pathogen speciation and hence endemism increased with isolation, as global dispersal distances decreased through a mechanism similar to the theory of island biogeography. To investigate if such an effect could be found, we analysed where 145 zoonotic diseases have emerged in human populations and found quantitative estimates of reduced dispersal of ectoparasites and fecal pathogens significantly improved our ability to predict the locations of outbreaks (increasing variance explained by 8%). There are limitations to this analysis which we discuss in detail, but if further studies support these results, they broadly suggest that reduced pathogen dispersal following megafauna extinctions may have increased the emergence of zoonotic pathogens moving into human populations