Proportion Of Meadows Research Articles

Local-scale habitat configuration makes a niche for wildlife encroaching into an urban landscape: grubbing sites of wild boar Sus scrofa in a city matrix

Urban environments may offer certain species diverse and abundant food resources of natural and anthropogenic origin. However, the local-scale configuration of habitats and urban infrastructure may influence foraging decisions regardless of the availability of food. In recent years, the expansion of wild boar Sus scrofa into areas significantly transformed by humans has been observed in many parts of its range. Grubbing (rooting) is a major foraging mode of the species, during which disturbance of the upper soil layers enables these animals to find and consume food items. However, the factors that determine the selection of grubbing sites in the urban landscape, where the balance between food availability and the avoidance of humans may influence foraging decisions, are not known. Our aim was to identify local-scale factors that influence grubbing site selection and the size of grubbed patches in an urban landscape. The characteristics of 108 wild boar grubbing sites in the city of Kraków (Poland) were compared to randomly selected control sites. The probable presence of a grubbing site was positively correlated with the proportion of meadows and fallow land in the vicinity and with increases in both canopy cover and distance to pavements. The size of a grubbed patch was positively correlated with the percentage of meadows in the vicinity, increasing distance to buildings and decreasing distance to pavements. We found a non-random pattern of grubbing sites in the urban landscape and indicated that the local-scale configuration of vegetation and urban infrastructure contribute to foraging site selection by wild boar. Our study highlights that the encroachment of wildlife into the urban landscape is a complex process, driven by both resource availability and the avoidance of human-related disturbances.

Quantifying heritability and estimating evolutionary potential in the wild when individuals that share genes also share environments.

Accurate heritability estimates for fitness-related traits are required to predict an organism's ability to respond to global change. Heritability estimates are theoretically expected to be inflated if, due to limited dispersal, individuals that share genes are also likely to share similar environments. However, if relatives occupy similar environments due, at least partly, to genetic variation for habitat selection, then accounting for environmental similarity in quantitative genetic models may result in diminished heritability estimates in wild populations. This potential issue has been pointed out in the literature, but has not been evaluated by empirical studies. Here, we investigate whether environmental similarity among individuals can be partly explained by genetic variation for habitat selection, and how this link potentially blurs estimates for heritability in fitness-related traits. Using intensive GPS monitoring, we quantified home-range habitat composition for 293 roe deer inhabiting a heterogeneous landscape to assess environmental similarity. To investigate if environmental similarity might harbour genetic variation, we combined genome-wide data in a quantitative genetic framework to evaluate genetic variation for home-range habitat composition, which is partly the result of habitat selection at settlement. Finally, we explored how environmental similarity affects heritability estimates for behaviours related to the risk avoidance-resource acquisition trade-off (i.e. being in open habitat and distance to roads) and proxies of individual performance (i.e. body mass and hind foot length). We found substantial heritability for home-range habitat composition, with estimates ranging from 0.40 (proportion of meadows) to 0.85 (proportion of refuge habitat). Accounting for similarity in habitat composition between relatives decreased the heritability estimates for both behavioural and morphological traits (reduction ranging from 55% to 100% and from 22% to 41% respectively). As a consequence, only half of these heritability estimates remained significantly different from zero. Our results show that similar genotypes occupy similar environments, which could lead to heritable variation being incorrectly attributed to environmental effects. To accurately distinguish the sources of phenotypic variation and predict the ability of organisms to respond to global change, it is necessary to develop quantitative genetic studies investigating the mechanisms underpinning environmental similarity among relatives.

Local pesticide use intensity conditions landscape effects on biological pest control.

Complex landscapes including semi-natural habitats are expected to favour natural enemies thereby enhancing natural pest biocontrol in crops. However, when considering a large number of situations, the response of natural biocontrol to landscape properties is globally inconsistent, a possible explanation being that local agricultural practices counteract landscape effects. In this study, along a crossed gradient of pesticide use intensity and landscape simplification, we analysed the interactive effects of landscape characteristics and local pesticide use intensity on natural biocontrol. During 3 years, using a set of sentinel prey (weed seeds, aphids and Lepidoptera eggs), biocontrol was estimated in 80 commercial fields located in four contrasted regions in France. For all types of prey excepted weed seeds, the predation rate was influenced by interactions between landscape characteristics and local pesticide use intensity. Proportion of meadow and length of interface between woods and crops had a positive effect on biocontrol of aphids where local pesticide use intensity was low but had a negative effect elsewhere. Moreover, the landscape proportion of suitable habitats for crop pests decreased the predation of sentinel prey, irrespectively of the local pesticide use intensity for weed seeds, but only in fields with low pesticide use for Lepidoptera eggs. These results show that high local pesticide use can counteract the positive expected effects of semi-natural habitats, but also that the necessary pesticide use reduction should be associated with semi-natural habitat enhancement to guarantee an effective natural biocontrol.

Non-invasive genetic sampling to predict wolf distribution and habitat suitability in the Northern Italian Apennines: implications for livestock depredation risk

Non-invasive genetic sampling has been used to reconstruct spatial patterns of carnivore distributions, identify regions where conflicts with human activities could threaten the survival of a species, and assess the effectiveness of conservation strategies. In this study, we used detailed information on wolf (Canis lupus) and livestock distributions to infer depredation risks in a wide area of the Italian Apennines. We carried out a General Niche Environment System Factor Analysis (GNESFA) to define the potential distribution of wolves genotyped from 8565 samples collected during 12 years of non-invasive genetic monitoring in 3622 locations. Habitat suitability models indicated that the proportion of meadows, altitude, slope, roughness, and distance from human settlements were the main factors positively related to the potential wolf distribution, in contrast with the extension of cultivated fields and human settlements. Results of GNESFA were used to infer the local depredation risk, which was high in 46.9 % of the pastures, and to rank the areas where prevention tools should be used with priority. In this way, the use of often-limited financial resources for prevention could be promoted in pastures with the highest depredation risk and conflicts between husbandry and wolf presence might be mitigated.

Habitat-density associations are not geographically transferable in Swiss farmland birds

Knowledge about associations between habitat and population density is essential for ecological studies and management alike, for instance, to identify high-density areas worthy of protection. Furthermore, habitat-density associations are important for setting targets, e.g. in agri-environmental schemes. However, habitat associations need to be constant across management units, which may be entire countries; otherwise management should be targeted at smaller, internally homogenous regions. We use data on 13 Swiss farmland bird species from 128 study sites to test for the generality of the association between territory density and six key habitat descriptors: the density of hedges and woodland edges, and the proportion of meadows, pastures, crops and fallow land at each study site. We modelled observed territory counts in overdispersed Poisson regressions, with and without zero-inflation, and including the interactions between four geographical regions and six habitat descriptors. To test for spatial transferability of habitat-density associations, we also fitted the corresponding main-effects models. As a continuous alternative to discrete regions, we fitted models with altitude and its interactions with habitat, to test for the generality of habitat-density associations across the 1885 m altitudinal gradient in our study (365–2250 m a.s.l.). Finally, we tested for nonlinearity as a possible reason for geographical non-transferability of habitat-density associations. The interactions between either region or altitude and habitat-density associations were important in 10 of 13 species, showing that habitat-density associations were not transferable. Discrete regions were the best descriptor of the spatial variation in habitat-density associations in seven species, and altitude in six. Simple overdispersed Poisson regressions were superior to zero-inflated models for 12 of 13 species. For 6 species nonlinearity was a sufficient explanation for the observed non-transferability. Non-transferability of habitat-density relationships might stem from biological reasons or from methodological inconsistencies. To distinguish between them, to suggest better management actions and to improve species habitat models, focused habitat-density studies ought to be replicated at various sites. Our study emphasizes the need for spatial stratification of conservation measures (e.g. agri-environmental schemes), otherwise, they may be inefficient or even harmful. Ideally, the spatial extent of internally homogenous regions ought to be investigated for efficient conservation management.

Patch and landscape factors shape community assemblage of bumble bees, Bombus spp. (Hymenoptera: Apidae), in montane meadows

Understanding the scale at which habitat influences species richness in terrestrial ecosystems is central to both ecology and conservation biology [Wettstein, W., Schmid, B., 1999. Conservation of arthropod diversity in montane wetlands: effect of altitude, habitat quality and habitat fragmentation on butterflies and grasshoppers. Journal of Applied Ecology, 36, 363–373]. Community composition may be influenced by habitat variation at patch and/or landscape-scales depending on the body size, home range area, and dispersal distances of the focal taxa [Calder III, W.A., 1984. Size, function, and life history. Harvard University Press, Cambridge, MA; Haskell, J.P., Ritchie, M.E., Olff, H., 2002. Fractal geometry predicts varying body size scaling relationships for mammal and bird home ranges. Nature 418, 527–530; Thomas, C.D., 2000. Dispersal and extinction in fragmented landscapes. Proceedings of the Royal Society Biological Sciences Series B 267, 139–145], not merely their phylogenetic affinity. We investigated the importance of habitat variables at different scales on the richness and abundance of bumble bees both annually and seasonally in Sierran montane meadows over two years. We found that both patch and landscape factors influence the species richness and abundance of bumble bees and these factors have a seasonal component to their importance. The proportion of meadow in the surrounding habitat was the most consistent positive influence on both species richness and abundance across years. In the second year, 2003, patch factors, plant species richness and current livestock grazing also influenced bumblebee species richness; plant species richness was positively correlated and current livestock grazing was negatively correlated with bumble bee species richness. Bumble bee abundance was positively influenced by meadow wetness and proportion of meadow in the surrounding habitat in both years. These data suggest conservation of pollinators depends on conservation planning with attention to the quality and context of the landscape.

Farm Size Growth and Participation in Agri‐environmental Schemes: A Configural Frequency Analysis of the Swiss Case

AbstractThis paper examines the relationship between farm growth and participation in agri‐environmental schemes, using the example of meadow extensification schemes in Switzerland. As a result of small farm sizes in Swiss agriculture, theory would suggest that economies of scale are considerable for market production activities, so that for growing farms it would be rational to intensify. Configural frequency analysis is used to identify and describe combinations of farm size development and proportion of meadows placed under agri‐environmental schemes. In the Swiss case, growing farms are likely to reduce their participation, whereas shrinking farms have a growing share of their meadows under extensification schemes.