Effects of agricultural intensification on the breeding success of corn buntings Miliaria calandra

Abstract

and {The Game Conservancy Trust, Fordingbridge, Hampshire SP6 1EF, UK Summary 1. Corn buntings Miliaria calandra have declined steeply in Britain and north-western Europe since the mid-1970s; changes in farming practice are believed to have been partly responsible. 2. We studied nesting corn buntings on the South Downs in west Sussex between 1995 and 1997 to examine the possible eects of agricultural intensi®cation on breeding success. The abundance of invertebrates around individual nests was sampled by sweep-netting in July. 3. Corn buntings provisioning nestlings foraged in grassy margins more than any other habitat relative to their availability within the maximum foraging range. The other habitats used more than expected were spring-sown barley, unintensi®ed grass and set-aside. Those used less than expected included winter-sown wheat and intensively managed grassland. The invertebrates most commonly fed to chicks were more abundant in foraging areas than elsewhere. Their density was negatively correlated with the number of insecticide applications both when cereal ®elds only were considered and when all foraging habitats were included. 4. The lower the abundance of chick-food invertebrates close to nests, the greater the distance from the nest at which parents foraged, and the longer such trips were in duration. The weights of nestlings, corrected for age using tarsus length, were positively correlated with the abundance of chick-food invertebrates. 5. The probability of nest survival was negatively correlated with the abundance of chick-food invertebrates close to the nest, apparently as a result of an increased risk of predation. 6. Agricultural intensi®cation in Britain, including the increased use of pesticides, has led to a widespread decrease in the availability of chick-food invertebrates on lowland farmland. If our results are typical of corn buntings in an arable environment, this decrease correlates with reduced breeding success. Depending on the mortality rates for¯edged chicks and older birds, this reduction may have contributed to the corn buntings' decline and may hamper recovery. 7. Farming practices that increase invertebrate availability ought to bene®t breeding corn buntings. Large-scale measures such as set-aside and the spring-sowing of cereals (especially if undersown with grass) depend heavily on overall agricultural policy. Small-scale initiatives might therefore be more feasible; these include the provision of grassy margins or beetle banks and selective spraying of headlands.

A sordély (emberiza calandra) élőhelyválasztásának vizsgálata a Mosoni-síkon

“…A sordély állománycsökkenése Európa-szerte megfigyelhető, legdrasztikusabban a kontinens észak-nyugati részén (DONALD et al, 1994, TUCKER & HEATH, 1994, EISLÖFFEL, 1997, BRICKLE et al, 2000, WATSON et al, 2009, PERKINS et al, 2011, BIRDLIFE INTERNATIONAL, 2014. Magyarországi állománycsökkenéséről már a XX.…”

“…Ez az időszak számos földön fészkelő énekesmadár, például a mezei pacsirta (Alauda arvensis), sárga billegető (Motacilla flava), cigánycsuk (Saxicola rubicola), rozsdás csuk (Saxicola rubetra), hantmadár (Oenanthe oenanthe) valamint a sordély második költésének ideje, így ezen fészekaljak nagyarányú pusztulása valószínűsíthető (BIRCKLE et al, 2000, BROYERA et al, 2014, STREBEL et al, 2015. Megkérdőjelezhető ezen felül a terület cél-faja, a túzok (Otis tarda) csibéinek túlélése is, hiszen ebben az időszakban még nehezen kapnak szárnyra, a gyorsan, sokszor vadriasztó lánc nélkül közlekedő gépek így fokozott veszélyt jelentenek e fajra nézve is.…”

Ecological restoration of farmland: progress and prospects

“…Further, ecological restoration was most commonly conducted at sites wherein the previous land uses were mining (37%), agriculture (18%; presumably arable cropping) and pasture (10%; Ruiz-Jaen & Aide 2005). Recent studies on the response of different animals to various habitat types on farmland have considered taxa such as bats (Wickramasinghe et al 2003), farmland birds (Brickle et al 2000) and butterflies .…”

“…For instance, spring-sown cereals provide better quality habitat for farmland birds than do autumn-sown cereals (e.g. winter wheat; Brickle et al 2000).…”

“…Within a farming unit, the sites that have been the targets of ecological restoration include arable land for fallow or undersowing, areas adjacent to sensitive urban areas such as schools and roads, farm woodland, field margins including uncultivated areas (set aside), headlands and hedges, grassland, land surrounding aquifers and land water catchments, mid-field strips (beetle banks and cover strips), roadside verges, scrub, waterways and riparian areas ( Thomas et al 1991;Fortin & Arnold 1997;Grey et al 1997;Brickle et al 2000;Wickramasinghe et al 2003;Bowie & Frampton 2004;Bro et al 2004;Carvell et al 2004;MacLeod et al 2004;Pywell et al 2004;Pywell et al 2005a,b;Bowie et al 2006). The paper by Ryan et al (2002) is a good example of how land attributes such as aspect, elevation, soil depth and slope can be used in farmscale site selection for farm forestry.…”