PARENT SESSION
Oral Session #63: Invasive Species: Terrestrial.
Presiding: D. Larson
Wednesday, August 7. 1:00 PM to 4:45 PM. Graham Meeting Room, TCC.
Effects of scale on data interpretation in plant communities: Implications for management and conservation in invaded grasslands.
Erskine, Jennifer*,1, Rejmanek, Marcel1, 1 University of California, Davis, Davis, CA
ABSTRACT- Invasive species cause functional and compositional changes in plant communities and alter ecosystem processes globally. Government agencies, researchers and private organizations are spending millions of dollars worldwide on understanding the biology and control of invasive species. Results from such experiments are applied to large-scale management projects. Often, data are collected from plots at scales of one square meter and extrapolated to represent plant community dynamics. Community changes in species richness and diversity of both the native and non-native flora are assessed using such small plot sizes. Fennel, Foeniculum vulgare, is considered one of California's invasive species of greatest ecological concern. Both The Nature Conservancy and Channel Islands National Park Service are attempting to control fennel and increase native plant species diversity on Santa Cruz Island, CA. From 1997 through 2001 plant community data were collected during a large-scale fennel management project in the Central Valley of Santa Cruz Island, CA. Six different plot sizes, ranging from 0.25m2 to 16m2, were used to collect percent cover data of all species in treated and untreated areas. Significant difference in species richness, total cover, and species diversity of natives, non-native grasses and non-native forbs are found when comparing data collected in small plots to those collected in the larger plot sizes. These differing interpretations of management results could have large implications in conservation of native species and controlling invasive species.
KEY WORDS: invasion, scale, species richness