Suchergebnisse

Context Intraspecific differences in behaviour can affect censuses and bias population estimates, suggesting that choice and implementation of census methods are fundamental, and need to be adapted to behavioural variations. Aims We investigated temporal variations in activity patterns during the rut among red deer (Cervus elaphus) categories and the implications for two different census methods. Methods We used a long-term dataset collected during 17 consecutive red deer rutting seasons in southernmost Sweden. The two census methods were: (1) a collection of observation ratios; and (2) a count of individuals including identification of males. Both methods are commonly used in ungulate management. Key results There was a difference in activity among age and sex categories, with a temporal variation in activity and/or presence at rutting grounds of adult (≥6 years) and subadult (2–5 years) males. Observation ratios of adult and subadult males increased from low at the start of the rut to a top level during peak rut, with subadults lagging behind adults. Before and during peak rut, the proportion of adult males was higher than that of subadults. After peak rut, the proportion of adult males decreased, whereas subadult males remained high, resulting in a higher number of subadults than of adults. The comparison of the two census methods revealed a strong correlation regarding the trends of population size and for the age and sex categories. There was also a strong consistency concerning the calf/female ratio. The male proportion was, however, consistently lower in the collected observations than in the counts. Conclusions The lower proportion of males in observations compared with counts may be explained by behavioural differences among male age classes, i.e. by temporal variations in presence and activity. That females, calves and yearling males are stationary during the rut, but adult and subadult males arrive and depart the rutting grounds at varying points of time, can lead to an underestimated male proportion in continuously collected observation data. Implications The results suggest that census should be conducted during peak rut, and that incorporating identification of individual males in the monitoring may be beneficiary.

Increasing numbers of previously threatened large grazing birds (cranes, geese and swans) are causing crop damage along their flyways worldwide. For example, the number of reported incidents of crop damage caused by common cranes Grus grus, followed by regulated inspections and governmental compensation in Sweden, has increased over the last few decades and was valued at ∼200,000 Euros in 2012. Consequently, their impact on agriculture is escalating which raises the need for evidence-informed preventative strategies. We surveyed arable fields for autumn staging common cranes in an area surrounding a wetland reserve in Sweden. We assessed the following factors in relation to the probability of cranes being present on fields: crop stage, crop type, distance to roost site, time of day, field size and time since harvest. Stubble fields had the highest probability of crane presence, progressively decreasing through grassland and grazing grounds, bare soil to growing crop. A stubble field at 5km from a roost site had a predicted probability (95% CI) of hosting cranes of 0.25 (0.19-0.32). The probability of cranes visiting a field was linearly and negatively related to distance to the roost site. For example, the probability of crane presence increased from 0.05 (0.03-0.07) to 0.09 (0.06-0.15) when distance decreased from 5 to 1km. At stubble fields, the probability of crane presence decreased with time since harvest and was highest for barley with progressively lower probability on wheat and oat. Illustrative scenario predictions developed from the models demonstrated that probability of crane presence could be high, 0.60 (0.42-0.77), if all favorable factors were combined (e.g. barley stubble, 1 day after harvest, 1km from roost site). Given the existing framework of international conventions and prohibition of culling, there is a need for preventative strategies to reduce crop damage. Based on our results, such strategies should focus on providing cereal stubbles as diversionary fields, especially close to wetland roosting sites. Stubble field availability can be achieved by careful crop rotation planning. We suggest that crop rotation and time of harvest should be added to flyway management plans recently developed for some large grazing bird species to facilitate stable co-existence between conservation practices and agricultural interests. KeywordsConservation; Crop protection; Geese; Wildlife conflict; Management

Protected areas are important to support biodiversity and endangered species. However, they are often too small to fulfill the resource requirements of many large and mobile wildlife species, especially when congregating in large numbers. In such cases, wildlife may overflow onto surrounding human-dominated land and cause impacts. The aim of the EU Natura 2000 network is to increase supranational connectivity between protected areas for migratory and protected species such as the common crane (Grus grus). The crane population along the Western European flyway has been increasing rapidly in recent decades, with peaks of 200,000 cranes at specific Natura 2000 sites. We studied 32 GPS-tagged cranes over four migration periods, to test the use of the network by cranes and the potential for impacts on adjacent farmland. During the nighttime, the probability that roosting cranes were located on Natura 2000 sites was 97%. During daytime, the probability of foraging cranes being located on arable land was 68%. The probability of foraging cranes occurring on agricultural fields close to Natura 2000 sites decreased with distance. Such foraging patterns may fuel conflicts between conservation and agricultural objectives. To resolve these conflicts we suggest improved cross-boundary collaboration and policy development among involved states, combined with stakeholder participation to implement effective compensation and damage prevention strategies which are focused upon networks of protected areas

Wild geese are increasing in agricultural and urban settings across Europe, leading to widespread human – geese interactions. This study examined how the public's acceptance of geese (attitude and acceptance capacity) varied depending on place dimensions, interactions with geese in different settings (place-based experience), and psychological factors, including wildlife value orientations, beliefs about the ecosystem services and disservices geese provide, and emotions. A survey was conducted in two municipalities with large goose populations in Sweden; Kristianstad and Örebro (n = 898). Results revealed a favorable view of the occurrence of geese, although a substantial share believed the number of geese was too high. Place-based experiences of geese were correlated with acceptance (e.g., more experience on beaches was associated with a negative attitude) and the importance of psychological factors for acceptance was confirmed. The study highlights the need to consider the public's experiences of geese for sustainable goose management.