Effects of Agricultural Practices on Field Use by Invertebrate-Feeding Birds in Winter

Tucker, Graham

doi:10.2307/2404488

Cited by 83 publications

(92 citation statements)

References 22 publications

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“…Both variables tended to reach higher values in plots located in crests of ancient transgressive dune fields, possibly because livestock rest in these areas and trample the vegetation into patches of contrasting height, and also because these features do not flood, enabling the development of cactuses and saplings. Disturbance caused by intermediate to light levels of grazing and trampling increases the structural diversity of the vegetation; this increases invertebrate abundance and diversity, thus benefiting invertebrateeating grassland birds (Gibson et al, 1992;tucker, 1992;perkins et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Bird-habitat associations in coastal rangelands of southern Brazil

Dias

Bastazini

Gianuca

2014

Iheringia, Sér. Zool.

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ABSTRACT. Nearly all remnants of temperate grasslands in southeastern South America are used for livestock ranching and are subject to habitat degradation resulting from this activity. Exploring how habitat features affect the composition of grassland avifaunal communities is a first step to understand how current cattle-ranching management practices impact avian diversity. We used canonical ordination to test for relationships between five habitat variables and the composition of the bird community in coastal grasslands in southern Brazil. We sampled pastures with different heights, from overgrazed short-grass to tall herbaceous vegetation. We recorded 1,535 individuals and 27 species of birds. The first ordination axis indicated a strong contribution of mean vegetation height on the composition of the bird community, whereas the second axis revealed the influence of herbaceous vegetation patchiness and woody vegetation cover. Three groups of species were revealed by the ordination: one more diffuse associated with intermediate and tall herbaceous vegetation, another with short grass, and a third with vegetation patchiness and woody vegetation. Species restricted to tall herbaceous vegetation are negatively impacted from habitat degradation resulting from overgrazing and trampling by livestock, and mowing and burning of tall plants. Occurrence of these species in our study area is related with the presence of swales immediately behind the dune system and where remnants of tall vegetation persist. Birds of pastures with ample cover of short herbaceous plants, including one globally threatened species and six other restricted to short-grass habitat, apparently benefit from local livestock management practices. Woody vegetation possibly functions as a keystone structure, enabling the occurrence in grasslands of avian species that rely on shrubby habitat. Although livestock ranching promotes the diversity of habitats by creating distinct patches of vegetation height in grasslands, current management practices directed to the maintenance of short grass pastures may eliminate an entire subset of species, including regionally threatened taxa, and reduce avian diversity. The maintenance of large patches of tall herbaceous plants is needed to ensure the survival of species reliant on this type of grassland structure in our study area. KEYWORDS.Habitat use, livestock ranching, grassland management, canonical ordination, "Campos" grasslands.RESUMO. Associações entre aves e variáveis de habitat em campos costeiros do sul do Brasil. Praticamente todos os remanescentes de campo temperado no sudeste da América do Sul são usados para a pecuária e estão sujeitos à degradação de habitat resultante dessa atividade. Explorar como a composição das comunidades de aves é influenciada por características de habitat é um passo inicial para compreender o impacto que as atuais práticas de manejo da pecuária em campos nativos exercem sobre a biodiversidade. Nós usamos ordenação canônica para testar as relações entre cinco variáveis de hab...

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Section: Discussionmentioning

confidence: 99%

Bird-habitat associations in coastal rangelands of southern Brazil

Dias

Bastazini

Gianuca

2014

Iheringia, Sér. Zool.

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“…It should be noted that the restriction of using only fields falling wholly within the 1-km square meant that the frequency distribution of field sizes was truncated, with the largest field being only 46.8 ha. Tucker (1992) suggested that extensive field surveys of wintering farmland birds should exclude species smaller than thrushes (Turdidae) on detectability grounds. The method used in this survey of walking across habitat patches to within 150 m of all points partially alleviated this problem because Skylarks were flushed.…”

Section: Field Sizementioning

confidence: 99%

Habitat selection by SkylarksAlauda arvensiswintering in Britain in 1997/98

Gillings¹,

Fuller²

2001

Bird Study

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“…The role of farmland habitats in the provision of winter resources for birds has been examined in a number of studies (e.g. Tucker 1992, Wilson et al 1996. Indeed, the provision of the appropriate habitat type during the winter months could reverse the dramatic declines of certain farmland specialists (Gillings et al 2005).…”

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confidence: 99%