Fred B. Samson

Great Plains Ecosystems: Past, Present, and Future

Abstract Little question exists that the main bodies of North American prairie (i.e., the tall-grass, mixed, and shortgrass) are among the most endangered resources on the continent. The purpose of this paper is to provide a past and present biological baseline by which to understand North American prairies and to provide a platform for future conservation. Events both immediate to the end of the Pleistocene and historic suggest that the present grassland conditions are different from those within which most of the grassland organisms evolved. Our analysis suggests that few grassland landscapes remain adequate in area and distribution to sustain diversity sufficient to include biota and ecological drivers native to the landscape. A robust and history-based scenario to conserve Great Plains grasslands is to 1) identify areas large enough to sustain an ecological system with all its biodiversity, 2) reverse significant losses in area of native grasslands, 3) ensure that restoration matches the grassland previously existing at that site, 4) refocus the profession of range management, and 5) establish a more meaningful agency design for grassland and natural resource management.

Ecology and Conservation of Great Plains Vertebrates

Section 1. The Great Plains Landscape as Vertebrate Habitats.- 1. Landscape Gradients and Habitat Structure in Native Grasslands of the Central Great Plains.- 2. Wetlands of the Great Plains: Habitat Characteristics and Vertebrate Aggregations.- 3. Water Management and Cottonwood Forest Dynamics Along Prairie Streams.- 4. Comparative Ecology of Native and Introduced Ungulates.- Section 2. Ecology of Vertebrate Assemblages Within Grassland Landscapes.- 5. Historical Changes in the Landscape and Vertebrate Diversity of North Central Nebraska.- 6. Ecology of Fishes Indigenous to the Central and Southwestern Great Plains.- 7. Avian Community Responses to Fire, Grazing, and Drought in the Tallgrass Prairie.- 8. Effects of Fire on Bird Populations in Mixed-Grass Prairie.- 9. Ecology of Small Mammals in Prairie Landscapes.- 10. Stopover Ecology of Transitory Populations: The Case of Migrant Shorebirds.- Section 3. Conclusion.- 11. Conservation of Grassland Vertebrates.

Conservation of Grassland Vertebrates

The Great Plains grasslands of North America have historically been referred to as the western hemisphere counterpart of the Serengeti Plains of Africa, with herds of roaming ungulates including bison (Bison bison), elk (Cervus elaphus), deer (Odocoileus spp.), and pronghorn (Antilocapra americana) and an associated large carnivore assemblage including grizzly bear (Ursus arctos), gray wolf (Canis lupus), and coyote (Canis latrans). Native peoples lived in harmony within this landscape, growing vegetables on the central and eastern Plains and no-madically hunting the bison herds of the western Plains. Estimates of bison numbers have been as high as 60 million. Although we will never know for certain, surely they numbered in the tens of millions (Shaw 1995). The number of carnivores also is uncertain, but Native Americans noted that wolves alone killed one-third of all bison calves each year (De Smet 1905).

Conserving the Biotic Integrity of the Great Plains

In the United States, a legal mandate for the conservation of biological diversity can be found in approximately 30 federal laws (Rein 1991). The mandate has now evolved into promoting a global strategy for conservation of diversity (World Resources Institute, The World Conservation Union, and United Nations Environment Programme 1992). The loss of biological diversity is recognized as a major national and global concern with potentially profound ecological and economic consequences (Council on Environmental Quality 1993). As a contribution to the multidisciplinary Great Plains Initiative, this chapter provides perspectives on the biological diversity of the Great Plains by defining (1) the concept, (2) landscape-level threats to its conservation, and (3) the conceptual approach to maintaining the biological integrity of the region in sustainable, yet economically developed, ecosystems.