Effects of Land Management Strategies on the Dispersal Pattern of a Beneficial Arthropod

Several arthropods are known to be highly beneficial to agricultural production. Consequently it is of great relevance to study the importance of land management and land composition for the conservation of beneficial aphid-predator arthropod species in agricultural areas. Therefore our study focusing on the beneficial arthropod Bembidion lampros had two main purposes: I) identifying the physical barriers to the species’ dispersal in the agricultural landscape, and II) assessing the effect of different land management strategies (i.e. use of pesticides and intensiveness) on the dispersal patterns. The study was conducted using genetic analysis (microsatellite markers) applied to samples from two agricultural areas (in Denmark) with different agricultural intensity. Land management effects on dispersal patterns were investigated with particular focus on: physical barriers, use of pesticide and intensity of cultivation. The results showed that Bembidion lampros disperse preferably through hedges rather than fields, which act as physical barriers to gene flow. Moreover the results support the hypothesis that organic fields act as reservoirs for the re-colonization of conventional fields, but only when cultivation intensity is low. These results show the importance of non-cultivated areas and of low intensity organic managed areas within the agricultural landscape as corridors for dispersal (also for a species typically found within fields). Hence, the hypothesis that pesticide use cannot be used as the sole predictor of agriculture’s effect on wild species is supported as land structure and agricultural intensity can be just as important

Landscape population genetics and the role of organic farming

This project aims at understanding the effect of different farming systems on the genetic diversity of common agricultural species. It is well known that organic farming generally improves the biodiversity and abundance of species in the agricultural landscape (Hole et al., 2005). A reduction in species number and abundance has been shown as a result of the intensification of farming suggesting a relationship between farming intensity and species abundance (e.g. Stoate et al., 2001). Anyway, none of the studies that investigated the effects of pesticides presence and farming intensity has investigated the effect on the genetic diversity and isolation of the populations. It has been shown that, despite the theoretical expectations, also very abundant species like Abax parallelepipedus can be divided in isolated and genetically distinct populations within very few years in response to human activity (e.g. construction of streets: Keller et al., 2004). Therefore, we chose two common agricultural species (field vole, Microtus agrestis, and a non-pest ground beetle, Bembidion lampros) belonging to different taxa and with different dispersal abilities, to investigate the effect of pesticide use and intensiveness of farming on their genetic structuring and diversity

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

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

Unravelling the Scientific Debate on How to Address Wolf-Dog Hybridization in Europe

Anthropogenic hybridization is widely perceived as a threat to the conservation of biodiversity. Nevertheless, to date, relevant policy and management interventions are unresolved and highly convoluted. While this is due to the inherent complexity of the issue, we hereby hypothesize that a lack of agreement concerning management goals and approaches, within the scientific community, may explain the lack of social awareness on this phenomenon, and the absence of effective pressure on decision-makers. By focusing on wolf x dog hybridization in Europe, we hereby (a) assess the state of the art of issues on wolf x dog hybridization within the scientific community, (b) assess the conceptual bases for different viewpoints, and (c) provide a conceptual framework aiming at reducing the disagreements. We adopted the Delphi technique, involving a three-round iterative survey addressed to a selected sample of experts who published at Web of Science listed journals, in the last 10 years on wolf x dog hybridization and related topics. Consensus was reached that admixed individuals should always be defined according to their genetic profile, and that a reference threshold for admixture (i.e., q-value in assignment tests) should be formally adopted for their identification. To mitigate hybridization, experts agreed on adopting preventive, proactive and, when concerning small and recovering wolf populations, reactive interventions. Overall, experts' consensus waned as the issues addressed became increasingly practical, including the adoption of lethal removal. We suggest three non-mutually exclusive explanations for this trend: (i) value-laden viewpoints increasingly emerge when addressing practical issues, and are particularly diverging between experts with different disciplinary backgrounds (e.g., ecologists, geneticists); (ii) some experts prefer avoiding the risk of potentially giving carte blanche to wolf opponents to (illegally) remove wolves, based on the wolf x dog hybridization issue; (iii) room for subjective interpretation and opinions result from the paucity of data on the effectiveness of different management interventions. These results have management implications and reveal gaps in the knowledge on a wide spectrum of issues related not only to the management of anthropogenic hybridization, but also to the role of ethical values and real-world management concerns in the scientific debate

Harbour porpoises (<i>Phocoena phocoena</i>) in the North Atlantic: Distribution and genetic population structure

The known geographical distribution (based on ship surveys, aerial surveys, incidental sightings, stranding and bycatch data) and the population genetic structure obtained from mitochondria DNA and nuclear DNA (isozymes and microsatellites) data analyses of the harbour porpoise in the North Atlantic have recently been reviewed and revised by the International Whaling Commission. The present review builds on these documents by integrating more recent genetic and distributional studies. Studies of the genetic structure of harbour porpoise populations tend to be concentrated in areas where samples are available which coincide with areas where incidental or directed catches or stranding take place. Nevertheless, recently, several genetic studies on the population structure have been able to reveal a more comprehensive picture of the harbour porpoise population structure in the Northwest and Northeast Atlantic, although not all areas have been subjected to analyses

Genetic indications of translocated and stocked grey partridges (Perdix perdix): Does the indigenous Danish grey partridge (Perdix perdix) still exist?

Non-local population stocking can have adverse genetic effects through loss of genetic diversity and introgressive hybridisation in wild populations exploited by man. The grey partridge (Perdix perdix) has been an important European game species for centuries, widely subject to translocation and stocking. After ca 80 years releasing reared grey partridges into Danish wild partridge areas, this study investigated whether an indigenous Danish grey partridge still existed. We predicted that (i) an indigenous Danish partridge would belong to the western European clade (W1) and (ii) would be more closely related to the historical, indigenous grey partridges than to farm bred partridges. These predictions were tested analysing the variation in the mitochondrial control region (CR1) and microsatellite markers in museum samples representing the ancestral indigenous Danish grey partridge, contemporary (recent) wild grey partridges and farmed grey partridges from the five largest farms in Denmark. Phylogeography- and population structure analyses showed traces of the indigenous Danish grey partridges amongst recent wild partridges in certain areas and significant genetic differences between reared, farmed partridges and historical- and recent partridges. The results also showed that the indigenous Danish grey partridges belonged to the western European clade (W1 haplotype). A foreign stocking effect was detected on the remote island of Bornholm, where the current population originated from introduced Danish and Bohemian grey partridges. The loss of haplotype diversity over time in certain geographical areas probably results from serious declines in wild Danish grey partridge numbers in recent decades. This combined with the 2 observation that hybridisation between released stocked and wild partridges can occur may complicate recovery of partridge populations