Association Analysis of Raptors on a Farming Landscape

Smallwood, Shawn K.; Nakamoto, Brenda J.; Geng, Shu

doi:10.1016/b978-012100130-8/50021-3

Cited by 9 publications

(5 citation statements)

References 17 publications

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“…Raptors have been considered sensitive to humaninduced environmental transformations (Newton 1979). Thus, species inhabiting temperate North American agricultural lanscapes have suffered greatly from modern improvements in agro-pastoralism (Colvin 1985;Schmutz 1989;Erichsen et al 1996;Smallwood et al 1996). Precise information is lacking, however, about the influence of these changes on European dryland raptors (Donázar et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Conflicts between Lesser Kestrel Conservation and European Agricultural Policies as Identif ied by Habitat Use Analyses

Tella¹,

Forero

Hiraldo

et al. 1998

Conservation Biology

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European pseudo-steppes have suffered from extensive changes in agricultural practices during the past decades with the disappearance of field margins and fallow systems and the increase of biocide treatments. The negative effect on wildlife has led to the adoption by the European Union of policies more compatible with environmental conservation, but decisions about optimal land use are difficult to make because of lack of information. We studied habitat use by the Lesser Kestrel ( Falco naumanni ), a globally vulnerable species, in a Spanish pseudo-steppe (Los Monegros) where traditional agro-grazing systems are still being practiced, and we compared the results with those of another Spanish pseudo-steppe where modern and intensive agriculture has been implemented. We focused on the use by Lesser Kestrels of habitats subject to changes provoked by recent agricultural policies. Habitat availability was determined in a 3-km radius around 11 colonies, where 23 Lesser Kestrels were radio-tracked during the chick-rearing stage. Habitat selection was determined through compositional analysis. The rank of selected habitats was similar for all kestrels, considering both habitats surveyed and habitats where kestrels hunted. Kestrels selected field margins and cereal fields and rejected abandoned crops and scrubland. This selectivity seemed to be due to prey availability. In the intensively cultivated areas the kestrels selected similar habitats but used only small foraging patches and obtained smaller prey than in the traditional agro-grazing systems, probably because of the irregular distribution of prey resources as a result of the intensive biocide treatments. Consequently, in intensively cultivated habitats Lesser Kestrels had larger home ranges (63.65 km 2 ) than in those with traditional systems (12.36 km 2 ). These differences are reflected in the productivity and population trends of both populations. Thus, the best strategy for conserving the Lesser Kestrel seems to be the maintainance of traditional cereal cultures with low biocide treatments and numerous field margins. Both agricultural intensification and marginal land abandonment (with subsequent scrubland invasion) have detrimental consequences for this and probably for other pseudo-steppe species. Positive management steps can be encouraged by recent agro-environmental regulations such as the 2078/92 European Union Reglament, which favors the creation of programs in which agricultural practices accord with wildlife conservation. Conflictos Entre la Conservación del Cernícalo Priniilla y la Politica Agraria Comunitaria Determinados por Estudios Sobre Uso del HábitatResumen: Durante las últimas décadas, las prácticas agrícolas en las pseudo-estepas europeas han sufrido fuertes cambios; los márgenes entre campos y los sistemas de barbechado han tendido a desaparecer mientras se incrementaba el uso de biocidas. Estas tendencias se aceleraron con la puesta en marcha de la Política Agraria Comúniteria (PAC) de la Unión Europea (UE). Sus efectos negativos sobre l...

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Section: Introductionmentioning

confidence: 99%

Conflicts between Lesser Kestrel Conservation and European Agricultural Policies as Identif ied by Habitat Use Analyses

Tella¹,

Forero

Hiraldo

et al. 1998

Conservation Biology

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“…They are attractive to wildlife for the same reason that alfalfa in the Sacramento Valley is preferred by wildlife (Smallwood and Geng, 1993b;Smallwood et al, 1996). Alfalfa and many cover crops are resourcerich and available to wildlife for many years.…”

Section: Discussionmentioning

confidence: 98%

“…Alfalfa and many cover crops are resourcerich and available to wildlife for many years. Pocket gophers proliferate in these environments, and they and their burrows are important resources for many animal species (Vaughan, 1961;Smallwood and Geng, 1993b;Smallwood et al, 1996), most of which are beneficial to the commercial crops. My preliminary research in cover crops shows that gopher populations can thrive in cover crops without causing significant damage to the commercial crops.…”

Section: Discussionmentioning

confidence: 99%

Managing vertebrates in cover crops: A first study

Smallwood

1996

Am J Alt Ag

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Little is known of how vertebrate pest and beneficial species respond to cover crops in vineyards and orchards. During spring 19941 interviewed 22 people who work with cover crops in California and searched for vertebrates and their signs in 36 field plots where cover crops were grown. Farmers usually relaxed concern for vertebrate pests after planting cover crops. But cover crops were thought to increase vertebrate damage to trees and vines when planted continuously across the rows or grown in orchards and vineyards less than three years old. Vertebrates usually were not abundant or harmful to the commercial crops and cover crops I examined. Gophers were most abundant in older, uneven, scrappy, or weedy cover crops. They preferred beneficial and insectary blends and Cahaba white vetch, and were least abundant in grasses, subclover mixes, and bur medic. Voles preferred nontillage clover mixes, but avoided bare ground under vine and tree rows. All small mammals were more numerous near streams and recently tilled fields. Cover crops attracted many predatory vertebrates, which improve the aesthetic quality of the farm and might keep animal damage to economically acceptable levels. Cover crops can contribute to wildlife conservation in California, especially if the area in cover crops continues to increase.

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“…Roadside surveys are convenient for obtaining information on distribution, population trends, and abundance of raptors (Fuller and Mosher 1981). Such surveys have been used extensively to determine relative abundance (e.g., Woffinden and Murphy 1977, Leptich 1994, Eakle et al 1996, Meunier et al 2000, population trends (e.g., Layne 1980), habitat associations (e.g., Preston 1990, Sorley and Anderson 1994, Garner and Bednarz 2000, Thiollay and Rahman 2002, perch use (e.g., Bohall and Collopy 1984, Smallwood et al 1996, Meunier et al 2000, Leyhe and Ritchison 2004, activity patterns (e.g., Meunier et al 2000), and species richness and diversity (e.g., Leptich 1994, Sorley andAnderson 1994). However, a number of factors may cause variation in raptor counts including differences in detectability across cover types, distance of observation (Millsap and LeFranc 1988) and time of day (Bunn et al 1995).…”

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confidence: 99%