© Marcel Burkhardt
Monitoring and promoting the brown hare in Switzerland
Brown hare populations in Switzerland have decreased over the last decades, and no reversal of this negative trend is in sight. To effectively promote the brown hare, the amount of ecological compensation areas on farmland has to markedly increase. Some case studies show that, along with the brown hare, a variety of farmland bird species can be promoted with habitat improvements.
1. Monitoring and population trend (1991 until now)
Over the last decades, brown hare numbers have gone down drastically. Since the early 1990s, the Swiss Ornithological Institute has surveyed various hare populations in different regions of Switzerland. On behalf of the Federal Office for Environment (FOEN), the Swiss Ornithological Institute coordinates the national Brown Hare Monitoring. In this survey, brown hare populations are monitored by cantonal departments in selected study areas. Owing to the standardised count method, it is possible to establish a long-term population trend of brown hares in arable and grassland regions of the Swiss Plateau (lowland).
2. Habitat improvement
Alongside the Swiss Brown Hare Monitoring, a brown hare project had been conducted to analyse whether ecological compensation areas positively affected brown hare populations (1991 until 2000). In suitable regional projects, fallows, flower-rich meadows and low hedges were implemented at large scale to promote the brown hare.
Each year in early spring, brown hares are counted with spotlight taxation at night. The open areas are illuminated (to approx. 200 m) with spotlights from pre-defined routes, and detected hares are mapped. The study sites comprise larger, open cultivated land with varying amounts of arable land and grassland.
Owing to long-term survey data, brown hare population trends for the Swiss Plateau can be analysed and compared between different sites varying in habitat quality. Suitable enhancement measures are developed for arable and grassland areas, and practical aims can be defined. Since the brown hare is an indicator species for the ecological quality of traditionally cultivated landscapes, other species also benefit from measures in favour of hares.
In Switzerland, brown hare populations are at a very low level. The population trend depends on land-use. On arable land, brown hare numbers have been higher since the beginning of the survey. During the late 1990s, densities were higher, but have gone down again in the last years. In grassland areas, populations have consistently decreased. Our results show that the brown hares can be promoted on arable land by implementing high-quality compensation areas. Unfortunately, such heterogeneous, open landscapes are becoming increasingly rare. Species-rich traditional farmland has greatly suffered from agricultural intensification, unplanned area development and increasing pressure from recreational activities.
The situation in grassland is alarming. The intensive use of meadows and pastures strongly impedes successful breeding of brown hares. Today’s agricultural policy and its requirements for ecological performance (“proof of ecological performance”, 7 % of utilised agricultural area must consist of ecological compensation areas) do not suffice to promote brown hares. However, in some case studies (Klettgau, Rhine valley of St. Gallen), brown hare densities have markedly increased after exemplary habitat improvement on several square-kilometers. The measures positively affected brown hare densities only after several years and only in regions with high-quality ecological compensation areas amounting to ca. 10 % of the agriculturally used land.
The persistent negative trend shows that the hitherto existing measures have not been enough to enhance the brown hare in Switzerland. The amount and quality of ecological compensation areas must be increased and their spatial distribution must be improved. The Swiss agricultural policy is challenged to provide the necessary incentives. Moreover, the ongoing urban sprawl in open agricultural landscapes must be stopped.
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