Arlettaz Raphaël

The decline of the European nightjar (Caprimulgus europaeus) in Switzerland: habitat change or drop in food supply? New guidelines for habitat management.

Project Number: CH-5871

Project Type:	Master
Project Duration:	07/17/2013 - 07/10/2014
Funding Source:	other ,
Leading Institution:	Universität Bern
Project Leader:	Prof. Raphaël Arlettaz Division of Conservation Biology Institut für Ökologie und Evolution Universität Bern Baltzerstrasse 6 3012 Bern Phone: +41 (0) 31 631 31 61 ; +41 (0) 31 631 45 11 FAX: +41 (0) 31 631 45 35 e-Mail: raphael.arlettaz(at)iee.unibe.ch http://www.ecolevol.unibe.ch

related to this project.

for which the project has a relevance.

Research Areas:

Biodiversity

Disciplines:

ecology
zoology
general biology
human and social sciences

Keywords:
European nightjar, forest management, moth community, vegetation structure

Abstract:

Over the last centuries, forests have undergone strong structural changes, with a general increase in vegetation density, often accompanied by a concomitant drop in biodiversity. Today, natural disturbances of woodland are either suppressed or their effects readily mitigated. The loss of natural forest dynamics has thus led to progressive habitat homogenization, which threatens species linked to the earlier stages of secondary vegetation succession, such as the European nightjar Caprimulgus europaeus. The densification of forest stands can affect their suitability as foraging grounds for this species, for instance by impeding accessibility, or alter prey supply. We assessed both habitat structural changes and food supply (moths, their main prey) in forest stands recently abandoned with habitat restorations and stands still occupied by nightjars in the Southern Swiss Alps. Occupied and abandoned sites differed significantly in relation to vegetation structure and moth abundance. Compared to abandoned restored sites, occupied sites harbored more snags, which might be used as song perches, while their ground cover showed a higher amount of mineral substrate, which is likely to hinder vegetation growth. In contrast, abandoned sites were less open, which is best highlighted by denser deciduous shrub and regeneration layers. Moreover, moth abundance and species richness were higher in occupied sites. In order to maintain and create favorable habitats for the nightjar, we recommend to promote semi-open habitats with a high degree of heterogeneity, including snags and patches of bare ground or mineral substrate. Such habitats are best created through natural hazards and we strongly recommend to tolerate if not promote natural disturbances in forests where feasible. In artificially restored habitats, these habitat requirements might be achieved by a combination of mechanical interventions and appropriate grazing to counteract vegetation succession.

Publications:
Keller, Nathalie (2014): The decline of the European nightjar
(Caprimulgus europaeus) in Switzerland: habitat change or drop in food supply? Master Thesis. University of Bern.



Last update: 12/29/16
Source of data: ProClim- Research InfoSystem (1993-2024)
Update the data of project: CH-5871

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