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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Applied Ecology. SUMMARY(1) The breeding ecology of lapwings (Vanellus vanellus L.) in relation to predation and agricultural land-use was compared in rough grazing and arable study areas in the Midland Valley of Scotland in 1984-86.(2) The laying season extended from late March until late May but was truncated on the arable site by crop growth in the spring cereal fields (the preferred nesting habitat).(3) In both study areas, the modal clutch size was four eggs (78% of clutches) and was not affected by laying date or whether or not previous clutches had been laid that year.(4) Hatching success was not affected by breeding density and the main cause of clutch failure was predation (most severe on the rough grazing study area); but early season losses due to cultivation were also heavy on the arable site. Disturbance by cultivation during laying was responsible for a greater frequency of smaller clutches early in the season than later on the arable site.(5) Chick movements, hatching and fledging success were heavily influenced by a combination of predation, weather, crop type and growth rate and timing of cultivation.(6) Productivity on the arable site was not normally sufficient to maintain the population. The main causes were egg losses during cultivation and poor chick survival due to crop growth.

With 7 figures in the text)The influence of egg size and composition on the size, quality and survival of lapwing chicks was examined on two farmland study sites in the Midland Valley of Scotland. Eggs comprised 33.1 % yolk, 61.3% albumen and 5.6% shell. Whereas the yolk and shell proportions decreased with increasing egg size, the albumen proportion increased. Most variation in egg size was attributable to differences between females but was also influenced by clutch number (eggs in replacement clutches on the rough grazing, but not the arable, site were smaller), clutch size (eggs were smaller in smaller clutches), maternal body condition (females in good condition produced larger eggs) and habitat (since females on the arable site fed more successfully, they were in better condition and laid larger eggs). Chick size, weight and survival were all influenced by egg size. The incubation period varied between 21 and 28 days (mean = 25.2) and was shorter in clutches laid later in the season.

Despite an increase in conservation efforts for shorebirds, there are widespread declines of many species of North American shorebirds. We wanted to know whether these declines would be exacerbated by climate change, and whether relatively secure species might become at–risk species. Virtually all of the shorebird species breeding in the USA and Canada are migratory, which means climate change could affect extinction risk via changes on the breeding, wintering, and/or migratory refueling grounds, and that ecological synchronicities could be disrupted at multiple sites. To predict the effects of climate change on shorebird extinction risks, we created a categorical risk model complementary to that used by Partners–in–Flight and the U.S. Shorebird Conservation Plan. The model is based on anticipated changes in breeding, migration, and wintering habitat, degree of dependence on ecological synchronicities, migration distance, and degree of specialization on breeding, migration, or wintering habitat. We evaluated 49 species, and for 3 species we evaluated 2 distinct populations each, and found that 47 (90%) taxa are predicted to experience an increase in risk of extinction. No species was reclassified into a lower–risk category, although 6 species had at least one risk factor decrease in association with climate change. The number of species that changed risk categories in our assessment is sensitive to how much of an effect of climate change is required to cause the shift, but even at its least sensitive, 20 species were at the highest risk category for extinction. Based on our results it appears that shorebirds are likely to be highly vulnerable to climate change. Finally, we discuss both how our approach can be integrated with existing risk assessments and potential future directions for predicting change in extinction risk due to climate change.