Crop diversity loss as primary cause of grey partridge and common pheasant decline in Lower Saxony, GermanyReport as inadecuate




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BMC Ecology

, 16:39

Conservation ecology and biodiversity research

Abstract

BackgroundThe grey partridge Perdix perdix and the common pheasant Phasianus colchicus are galliform birds typical of arable lands in Central Europe and exhibit a partly dramatic negative population trend. In order to understand general habitat preferences we modelled grey partridge and common pheasant densities over the entire range of Lower Saxony. Spatially explicit developments in bird densities were modelled using spatially explicit trends of crop cultivation. Pheasant and grey partridge densities counted annually by over 8000 hunting district holders over 10 years in a range of 3.7 Mio ha constitute a unique dataset wildlife survey of Lower Saxony. Data on main landscape groups, functional groups of agricultural crops consisting of 9.5 million fields compiled by the Integrated Administration and Control System and landscape features were aggregated to 420 municipalities. To model linear 8 or 10 year population trends for common pheasant and grey partridge respectively we use rho correlation coefficients of densities, but also rho coefficients of agricultural crops.

ResultsAll models confirm a dramatic decline in population densities. The habitat model for the grey partridge shows avoidance of municipalities with a high proportion of woodland and water areas, but a preference for areas with a high proportion of winter grains and high crop diversity. The trend model confirms these findings with a linear positive effect of diversity on grey partridge population development. Similarly, the pheasant avoids wooded areas but showed some preference for municipalities with open water. The effect of maize was found to be positive at medium densities, but negative at very high proportions. Winter grains, landscape features and high crop diversity are favorable. The positive effect of winter grains and higher crop diversity is also supported by the trend model.

ConclusionsThe results show the strong importance of diverse crop cultivation. Most incentives favor the cultivation of specific crops, which results in large areas of monocultures. The results confirm the importance of sustainable agricultural policies.

KeywordsHabitat model Trend analysis Grey partridge Common pheasant Citizen science Diversity Maize cultivation AbbreviationsIACSIntegrated Administration and Control System

WTEWildlife survey Lower Saxony Wildtiererfassung Niedersachsen

EEGrenewable energy directive Erneuerbare-Energien-Gesetz

LEA-Portalinternet portal for rural development and agricultural subsidies Landentwicklung und Agrarförderung

SLAservice center for rural development and agricultural subsidies Servicezentrum Landentwicklung und Agrarförderung

PCAprincipal component analysis

CCAcanonical correlation analysis

NMDSnon-metric multidimensional scaling

GAMMgeneralized additive mixed model

GAMgeneralized additive model

CAPcommon agricultural policy

Electronic supplementary materialThe online version of this article doi:10.1186-s12898-016-0093-9 contains supplementary material, which is available to authorized users.

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Author: Katrin Ronnenberg - Egbert Strauß - Ursula Siebert

Source: https://link.springer.com/



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