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Effects Of Field Size And Landscape Composition On Grassland Birds In South-Central Iowa, David Joseph Horn, Rolf R. Koford, Malinda L. Braland

Journal of the Iowa Academy of Science: JIAS

Many species of grassland birds have been shown to avoid smaller fields. The avoidance of smaller fields, however, has not been consistently reported; avoidance may occur in one study, but not in another. To examine one possible reason for these inconsistencies, we examined how landscape composition influenced the relations between occurrence or abundance and field size. The study took place during the 1998 breeding season on 44 Conservation Reserve Program (CRP) fields located in Adair, Ringgold, and Union counties. The relations between occurrence, abundance, and field size were not influenced by landscape composition for any species.

Grasshopper Sparrow, Ammodramus savannarum, …

Decline Of Iowa Populations Of The Regal Fritillary (Speyeria Idalia) Drury, Diane M. Debinskl, Liesl Kelly

Journal of the Iowa Academy of Science: JIAS

The Regal Fritillary butterfly, Speyeria idalia Drury (Lepidoptera: Nymphalidae, Argynninae), is a prairie endemic species which has exhibited a dramatic decline in Iowa during the last few decades. Tallgrass prairie is the primary habitat of S. idalia and the butterfly's presence is correlated with the presence of violets (Violaceae). Due to the extensive habitat fragmentation of Iowa prairies, both the butterfly and its host plant populations are limited primarily to unplowed, relatively pristine prairies. Thus, S. idalia is an excellent case study of a prairie endemic species. Here, we report on the results of a two-year survey of the insect …