Vole spatial distribution and dispersal in European organic and conventional farming systems

North European landscapes are highly dominated by agriculture, where small biotopes, e.g. meadows, uncultivated grassland, hedge rows, field boundaries, surroundings of water ponds, only comprise a low percentage. In recent years organic farming has expanded in acreage due to customers increased awareness regarding pesticide and fertilizer use and biodiversity conservation. However, organic farming has changed from an extensive production with small fields, low mechanical impact and high crop diversity towards larger fields, intensive mechanical treatment, lower weed densities and lower field diversity. Still, organic farms could play an important, role in the agricultural landscape as refuges for some small mammal species. We studied the responses of populations to habitat patches of different size and different surrounding management strategies (ecological and conventional farming). Studies were performed at two localities in Denmark, Kalø Estate in Eastern Jutland and the Bjerringbro area in Central Jutland. The sampling sites were represented by cultivated grassland habitat, small biotopes within cultivated fields and hedgerows between fields in rotation. Small mammal species assemblages were low in numbers in cultural farmland, and, on a property basis, not significantly different between organic and conventional farms. Very few species and individuals were present in the field matrix, and the small biotopes were by far the most important source of species richness. Species density was positively correlated with the size of the habitat, and, generally, more voles were found in organic habitat patches than in conventional ones. More field voles were found in organic grassland and more bank voles (Myodes glareolus) in organic hedge rows than in conventional ones. Telemetry studies of field voles showed low rates of dispersal and low colonization rates of the more or less isolated small biotopes at the time of year with no vegetation cover in the surrounding fields. We found no significant correlations between distance to nearest stepping stones/dispersal corridors and small mammal densities or species composition. In agricultural areas landscape structure influences the small mammal species living in this fragmented habitat matrix. The value of organic farms in respect to small mammal biodiversity depends mainly upon the number and area of small biotopes, and only to a minor degree upon the management of the fields. This is presumably related to a more dense and diverse vegetation cover, due to a lack of pesticide and fertilizer treatment in the organically managed small biotopes

Organic farms as refuges for small mammal biodiversity in agro ecosystems

Habitat fragmentation, the process by which relatively continuous habitats is broken into smaller pieces, occurs in natural systems but is to a high degree also human-induced through landscape use. Fragmentation of the landscape produces a series of habitat patches surrounded by a matrix of different habitats and land use regimes. The major landscape consequences of fragmentation are loss of habitat, reduction in habitat patch size, and increasing isolation of habitat patches. In general, population performance declines in response to habitat loss but size of remaining area and isolation effects is known also to influence the population trend. Small mammals are well suited for examination of population responses to habitat fragmentation as they have modest spatial requirements and short generation times. In theory, organic farms could play an important role in the agricultural landscape as refuges for some small mammal species, as the lack of pesticide and fertiliser treatment, less weed control, more diversified crop structure and a general environmental friendly attitude, form a basis for habitats that provide cover and food for small mammals, and thus for larger predators of these species. Furthermore, density and area of small biotopes could be expected to be higher in the organic farms, thus leading to a decreased distance between optimal habitats. This study compares species diversity and abundance of small mammals in conventional farms and intensively and extensively grown organic farms. In a wide range of different fields in conventional and organic farms, the diversity and density of small mammals were investigated by live-trapping sessions, comprising trap lines with 15 meters between each trap. We studied the responses of populations (belonging to 11 species of small mammals) to habitat patches of different size and different surrounding management strategies (ecological and conventional farming). We found a general correlation between the number of small mammal individuals and small biotope size. This correlation applies in autumn as well as in spring. There is only a weak tendency for more small mammals in small biotopes within organic farms compared within conventional farms. The number of small mammal species stabilises at small biotope sizes around 1000 square meters. The value of organic farms in respect to small mammal biodiversity depends mainly upon the number and area of small biotopes, and only to a minor degree upon the treatments of the fields

ORGANIC FARMS AS REFUGES FOR SMALL MAMMAL BIODIVERSITY

Habitat fragmentation, the process by which relatively continuous habitats is broken into smaller pieces, occurs in natural systems but is to a high degree also human- induced through landscape use. Fragmentation of the landscape produces a series of habitat patches surrounded by a matrix of different habitats and/or land use regimes. The major landscape consequences of fragmentation are loss of habitat, reduction in habitat patch size, and increasing isolation of habitat patches. In general, population performance declines in response to habitat loss but size of remaining area and isolation effects is known also to influence the population trend. Small mammals are well suited for examination of population responses to habitat fragmentation as they have modest spatial requirements and short generation times. In theory, organic farms could play an important role in the agricultural landscape as refuges for some small mammal species, as the lack of pesticide and fertiliser treatment, less weed control, more diversified crop structure and a general environmentalfriendly attitude, form a basis for habitats that provide cover and food for small mammals, and thus for larger predators of these species. Furthermore, density and area of small biotopes could be expected to be higher in the organic farms, thus leading to a decreased distance between optimal habitats

Wildlife friendly agriculture: which factors do really matter? A genetic study on field vole

The distribution of genetic differentiation and the directions of gene flow were determined mainly by landscape factors: thus the expectation that organic fields act as genetic reservoir was not met. The fact that agricultural area presented more sub-populations than the undisturbed one, together with the importance of connectivity and habitat size in shaping gene flow and genetic differentiation, shows that switching to organic farming might not be enough to ensure the conservation of species in the agricultural environment. These results emphasise the need to include landscape structure in management policies

Home range and dispersal of the field vole Microtus agrestis in an organic agro-ecosystem

During 2008-2011 field voles (Microtus agrestis) were studied in a Danish agro-ecosystem in connection with a programme elucidating the role of organic farming as refuge for biodiversity, due to the observed biodiversity losses in conventional farmland. The aim of the study was to quantify home ranges and movements of voles in order to test a hypothesis that vole populations living in organic farm could colonize unoccupied areas in conventional farms. Voles were radiocollared and tracked until death or disappearance. Results showed that vole home-ranges were larger during onset of the breeding season than during the height of the breeding season and the non-breeding period. Males had larger home ranges than females. Voles occupying isolated small biotopes had restricted home range and only few individuals crossed fields from one small biotope to another. Although crossings do occur, the magnitude of dispersal seems restricted

Organic farming and biodiversity - the impact of organic farming on nature

Organic farming is generally acknowledged for its positive effects on biodiversity and other landscape services. However, the intensity of farming has changed significantly through the last decade as ranks of traditional holistic organic farmers have been joined by much more economically-driven new organic farmers. At the same time there have also been steady improvements in farming methodology and crop types resulting in efficiency in organic farming which can often rival its conventional counterparts. Therefore, large variations occur between organic farms

Økologisk jordbrug som refugier for biodiversitet (Refugia)

• Økologiske marker har mere ukrudtsbiomasse end konventionelle. • Der er flere blomstrende arter i økologiske hegn end konventionelle forudsat, at der er kontinuitet i den økologiske drift. • Der er flere små pattedyr i små økologiske biotoper end konventionelle. • Fjernmålinger fra fly eller satellit, kaldet remote sensing, kan skelne hvilken afgrødetype der dyrkes, samt forekomsten af småbiotoper. • Uanset driftformen er det vigtigt at inddrage naturhensyn i driften, dvs., at der findes ekstensivt drevne arealer (græsmarker, overdrev, enge) til natur og direkte afsatte arealer til natur

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700