Landscape vs. Local Habitat Scale Influences to Insect Communities From Tallgrass Prairie Remnants

Abstract

Abstract. Habitat loss and fragmentation currently threaten ecosystems worldwide, yet remain difficult to quantify because within-fragment habitat and landscape-scale influences often interact in unique ways. Although individual species respond to fragmentation differently, large-scale conservation planning must unavoidably target multiple species. Although information on a population's response to fragmentation is critical, and measurements of species richness provide useful insights, exclusive reliance on these responses may mask important information about the taxonomic composition of assemblages in response to fragmentation. The North American tallgrass prairie ecosystem is one of the most threatened and fragmented ecosystems in the world, and insects are significant contributors to its biodiversity. In remaining grassland fragments, we evaluated within-fragment influences in conjunction with landscape-scale responses of representative insect communities from four feeding guilds: generalists, specialists, multiple life stage habitat use, and predators. Fragment-specific attributes capable of influencing insect diversity include plant species composition, plant biomass, abundance of blooming flowers, and vertical habitat heterogeneity created by the vegetation. Landscape-scale factors expected to influence patterns of insect species diversity include fragment size and shape as well as the spatial configuration of fragments. Ordination techniques were used to summarize composition of each feeding guild assemblage of each fragment, and structural equation modeling was used to examine the direct and indirect effects of fragmentation with influences from local habitats. Generalists (Orthoptera), mixed-modality feeding that changes with life stage (Lepidoptera), and specialist herbivores (Curculionidae) all responded directly to withinsite characterizations of the plant community. Site management from large ungulate grazing or mowing for hay production consistently had an indirect effect on the insect community through influences on plant community composition. The predator assemblage (Coccinellidae) was influenced directly by fragment shape. To maintain insect biodiversity in tallgrass prairie fragments, these results indicate that conservation practices should focus on communities in order to maintain insect biodiversity in tallgrass prairie fragments. Landscapescale factors must also be considered when making conservation decisions, primarily because predators (top trophic level organisms) are more likely to respond to regional changes.

Butterfly responses to prairie restoration through fire and grazing

“…Habitat losses across the globe have resulted from the conversion of land for agriculture and development (Saunders et al, 1991;Stoner and Joern, 2004). Grassland ecosystems are especially vulnerable to losses from agricultural development and, in fact, the tallgrass prairie region of North America is one of the most endangered ecosystems on Earth (Smith, 1981;Noss et al, 1995).…”

Does forest loss affect the communities of trap-nesting wasps (Hymenoptera: Aculeata) in forests? Landscape vs. local habitat conditions

“…Nevertheless, there are studies that show local habitat conditions have more influence than landscape features on insect communities (Collinge et al 2003;Summerville and Crist 2004). Both sets of findings imply that factors of both landscape and local habitat affect communities differently, depending on the organisms, seasons, ecosystems and the complex interactions among them (Stoner and Joern 2004;Tscharntke et al 2005).…”

Effects of Host plant, Nectar plant and Vegetation types on Butterfly Communities

“…또한 나비 군집은 흡밀식물의 다양성과도 밀접한 관계를 보 이고 있어 (Stoner and Joern, 2004) 특정한 종이나 꽃의 화색이 나 형태를 선호하고 (Porter et al 1992) 흡밀식물의 위치를 인 지할 수 있는 능력이 있는 것으로 알려져 있다 (Gilbert and Singer, 1975). 뿐만 아니라 흡밀식물의 풍부도는 나비를 유인 하는데 중요한 역할을 한다고 할 수 있으며 (Saarinen and Jantunen, 2005;Kitahara et al, 2008), 관목과 초본의 흡밀식 물이 목본식물보다 많이 모이는 것으로 나타나고 있다 (Nimbalkar et al, 2011).…”