Markus Jenny

Territorialität und Brutbiologie der FeldlercheAlauda arvensis in einer intensiv genutzten Agrarlandschaft

In einer intensiv landwirtschaftlich genutzten Fläche des schweizerischen Mittellandes wurden 1983–1987 vier Feldlerchenaggregationen mit maximal 39 Brutpaaren untersucht. Die Tradition (Ortstreue) bestimmte in erster Linie die Revierwahl und das Verteilungsmuster. Die Reviere waren mit

Suitability of patches and in‐field strips for Sky Larks Alauda arvensis in a small‐parcelled mixed farming area

\bar x = 3,3 \pm 0,9

Ecologically enhanced areas – a key habitat structure for re-introduced grey partridges Perdix perdix

ha sehr groß; ihre Größe korrelierte negativ mit der Anzahl Parzellen pro Fläche und der Kulturendiversität. Die Nutzung des Ressourcenangebots (Nistplatz, Nahrung, Schutz) war abhängig von den Fortbewegungsmöglichkeiten. In großparzellig strukturierten Flächen mit geringer Kulturendiversität kam es häufig zu Revierverschiebungen und Reviervergrößerungen. Die Feldlerche versucht, im Laufe der Brutperiode den Getreideanteil im Revier zu verkleinern und Kulturen wie Rüben, Kartoffeln und auch Mais zu aquirieren. Die Nistplatzwahl zeigte eine deutliche Präferenz für alle nicht zu dicht stehenden, grasartigen Kulturen (Weizen, Hafer, Fettwiese). Eine Vegetationshöhe von 15–25 cm und eine Bodenbedeckung von 20–50 % bieten optimale Bedingungen für den Nestbau. 51 % aller Nester wurden in der Fettwiese angelegt, 20 % im Winterweizen und 18 % im Mais. Je nach Bewirtschaftungsart brüteten die ♀ im Mittel 2,4–2,8mal pro Brutsaison. Die Schlüpfrate von 220 Gelegen betrug 0,58. 44 % der geschlüpften Jungvögel verließen das Nest. Der Bruterfolg (nestverlassende Junge/gelegte Eier) lag bei max. 25 %. Dem Fütterungsverhalten der Altvögel nach zu schließen, wurden maximal 50 % der nestverlassenden Jungen flügge. Durchschnittlich war mit 0,9 flüggen Jungen pro Brutpaar und Jahr zu rechnen. Brutverluste waren kulturspezifisch und daher in erster Linie vom Neststandort abhängig. In 1983–1987 four plots (total surface 307 ha) with up to 39 breeding pairs were studied in an area of intensive cultivation in the Swiss Lowlands (390 m asl). Distribution pattern and selection of territories are determined by a strong site tenacity of the birds. The size of territories averaged 3,3±0,9 hectares. It correlates negatively with the number of different crops per unit area and the diversity of cultures. The mobility within the vegetation determined which types of farmland ressources may be used for nesting, feeding and cover. Shifts of territories and attempts to enlarge them were frequent in areas of large plots with low crop diversity. During the season, Skylarks tried to reduce the proportion of cereal fields within their territory and to gain plots planted with sugar-beet, potatoes and corn. Their choice of nesting sites showed a strong preference for less dense grass crops such as wheat, oat or meadows. Optimal conditions for nest sites were in fields with a vegetation height of 15–25 cm and a ground coverage of 20–50 %. 51 % of 220 nests were constructed in heavily manured meadows, 20 % in winter wheat fields and 18 % in corn fields. Females bred on average 2,4–2,8 times per breeding season, depending on the type of cultivation (agriculture, husbandry). Hatching rate was 58 % out of 220 clutches, and 44 % of the hatched young left the nest. Maximum breeding success (i. e. young birds leaving the nest/number of eggs laid) was thus maximal 25 %. Observations of parental feeding behaviour suggest that a maximum of 50 % of the young larks which leave the nests survive to the age of fledging. It is estimated that 0,9 fledglings are raised per breeding pairs and year. Losses of broods vary according to farming practises in the different crops and therefore are largely depending on nesting sites.

Impact of landscape improvement by agri-environment scheme options on densities of characteristic farmland bird species and brown hare (Lepus europaeus)

This paper discusses the protection of biodiversity by means of market-based activities in the food sector and the preconditions and context that provide fertile ground. The variables investigated are the regional production factors involved, the entrepreneurship demonstrated, the kind of niche market developed, and the various kinds of support provided. A case study of a Swiss market activity designed to restore and protect biodiversity is presented; it concerns the cultivation of a traditionally grown wheat species combined with measures to protect wildlife and flora. The wheat is processed into a variety of products, which are sold within the region. The organization of the activity, its economic development and its ecological implications are presented. The discussion reveals the particularities of such endeavours that are of relevance to the economics of regional development (e.g. limited product and market development, reliance on subsidies, need for broad coalitions) and factors of success (e.g. networking, involvement of research, political support). Conclusions with regard to policy are as follows: (1) support in the very early stages is needed (e.g. start-up capital, capacity building, partner-like support from administration); (2) biodiversity-sound agricultural activities rely on subsidies; and (3) a propitious framework for such market activities is to be conserved.

20% loss of unimproved farmland in 22 years in the Engadin, Swiss Alps

Capsule Sky Larks make use of agri‐environment measures in winter wheat for nesting and foraging during nestling provision. Aims To determine the suitability of in‐field measures (patches and strips) for breeding Sky Larks in small‐parcelled Swiss lowland farmland. Methods Focal territories established over winter wheat fields with in‐field measures (four patches or one strip per hectare sown with arable weed mix) and over conventionally managed wheat, were surveyed during one breeding season. Territories were digitized in a geographical information system based on the mapping of singing males. Breeding pairs were observed to determine the position of nest‐sites and foraging spots during nestling provisioning. Breeding success and chick body condition were also determined. Results Winter wheat fields containing in‐field measures were more likely to be part of a Sky Lark territory from June onwards than conventional winter wheat fields. Conventional winter wheat fields were used significantly less in July than in May and June. When a nest was built in winter wheat it was significantly more often in or near an in‐field measure than expected. During the nestling period, the in‐field measures were the preferred locations for foraging followed by field borders and spring sown crops. Conclusion The tested in‐field measures help to prolong the use of winter wheat for Sky Larks during the breeding season. In a mixed and small‐parcelled farming system, their application is not as urgent as in larger‐scale monocultures. Nevertheless, Sky Larks (as well as other wildlife species) use them actively. IP‐SUISSE (the initiative to encourage integrated farming in Switzerland) encourages farmers to implement patches and in‐field strips on a voluntary basis.