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ABSTRACT Understanding how predators respond to fluctuations in prey density has important conservation and management implications, particularly for threatened and endangered specialists. However, directly linking prey densities to predator behavior and demography over broad spatial and temporal scales is rare, in part, because it can be prohibitively expensive and time-consuming to quantify prey density over large areas. We link nesting data collected by a long-term monitoring program for the endangered snail kite ( Rostrhamus sociabilis plumbeus) with 44 density estimates of its primary prey, the Florida apple snail ( Pomacea paludosa), collected by multiple, smaller-scale studies from 2002 to 2010. We found evidence that key components of kite breeding biology-nest density and the number of young fledged per successful nest-were positively related to snail density. Although previous studies have shown that densities greater than approximately 0.1-0.2 snails/m2 may be necessary to sustain profitable foraging and that capture times for individual foraging kites begin to level off as snail densities exceed approximately 0.4 snails/m2, we found continued numerical responses in snail kite reproductive parameters at greater snail densities. At occupied sites (i.e., snail-sampling sites in which ≥1 snail kite nest was present within a 2-km radius during the primary sampling period: Mar-May), the average snail density was 0.45 snails/m2 (SE = 0.12, n = 17), whereas that of unoccupied sites was 0.12 snails/m2 (SE = 0.02, n = 27). Along the snail density gradient from 0.2 to 0.4 to 1.2 snails/m2, model predictions indicated that 1) the probability of site occupancy (by nesting kites) increased from 0.48 to 0.69 to 0.90, 2) local nest abundance of occupied sites increased from 4 to 7 to 16 nests, and 3) the probability of a successful nesting attempt fledging more than 1 young increased from 0.02 to 0.07 to 0.43. We found no evidence of a snail density effect on nest survival. Understanding the differential effects of snail density on various components of snail kite breeding biology is essential to the development and implementation of management tools used for snail kite conservation and Everglades restoration. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

We determined how the composition and patchiness of eastern South Dakota agricultural landscapes surrounding cornfields and the abundance of aphids in cornfields affected the abundance of adult coccinellids in cornfields. Four species of Coccinellidae were common in cornfields during the three-year study. Five variables describing the composition and patchiness of the landscape surrounding cornfields (% of pasture/grassland, % of wooded land, % of Conservation Reserve Program land, % of wetland, and boundary density) and abundance of aphids in the cornfields were used as predictor variables to construct stepwise multiple regression models to describe the abundance of each species of coccinellid in the cornfields. Regression models explained for 8–45% of the variation in abundance of adult Coccinellids depending on species. Abundance of aphids entered into regression models for three of the four species. The regression coefficient for aphid abundance was positive in models for two species, but was negative in the model for C. maculata. Each of the five landscape variables was included in a regression model for one or more coccinellid species. Results are discussed in relation to the biology and ecology of the species of Coccinellidae that inhabit cornfields in eastern South Dakota. [Copyright &y& Elsevier]