Abstract
Spiders (Araneae) are an important group of generalist predators in arable land. In temperate climates, spiders recolonise cropland annually from the surrounding landscape. In arid climates however, irrigated crops and the surrounding landscape matrix offer sharply different habitat conditions and this might negatively affect spider migration into crops. We studied whether the spider fauna in desert crops is influenced by the surrounding landscape in a similar way to that found in temperate climates. Spiders were sampled with pitfall traps in 13 wheat fields (Triticum aestivum L.) in the Negev Desert (Israel). The fields were situated along a gradient from crop- to non-crop-dominated landscapes (1-72% non-crop habitats). Species richness of spiders in wheat fields increased with the percentage of non-crop habitats in the landscape. In addition, activity-densities of crab spiders (Thomisidae) and cobweb spiders (Theridiidae) were enhanced by high percentages of non-crop habitats in the surrounding landscape. Activity-densities of the dominant sheetweb spiders (Linyphiidae) showed no significant response to landscape composition. As the immigrant spider families employ different foraging strategies than the dominant sheetweb spiders, they functionally enriched the spider fauna in crops and potentially increase the range of prey types consumed by spiders. Thus, non-crop habitats can be expected to increase the potential for biological control by spiders in nearby crops.
| Original language | English |
|---|---|
| Pages (from-to) | 68-74 |
| Number of pages | 7 |
| Journal | Agriculture, Ecosystems and Environment |
| Volume | 137 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - 15 Apr 2010 |
| Externally published | Yes |
Bibliographical note
Funding Information:We would like to thank all the farmers who allowed us to access their fields. Special thanks go to Iris Museli, Gershom Levy and Milan Rezac for assistance in spider identification and Heather Murray, Yann Clough and Jason Tylianakis for useful comments on earlier versions of the manuscript and for linguistic advice and to Florian Menzel and Fränzi Korner for statistical advice. Four anonymous reviewers provided valuable comments on an earlier version of this manuscript. This study was supported by the Bern University Research Foundation . This is publication number 666 of the Mitrani Department of Desert Ecology.
Keywords
- Araneae
- Arid climate
- Ballooning
- Ecosystem services
- Foraging strategy
- Generalist predators
- Migration mode
- Negev desert
- Pest suppression
- Spatial scale
