SS3.16 Lentic-Lotic Linkages in Freshwaters: Comparisons from Different Ecosystems
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
STARKWEATHERPL, University of Nevada, Las Vegas, Las Vegas, USA, strkwthr@ccmail.nevada.edu
 
SPECIES AND GENE FLOW AMONG BASINS IN HIGH AND LOW ELEVATION ARID-LAND AQUATIC SYSTEMS
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High elevation arid-land ponds (ca. 3000 m) are generally permanent systems in basins filled by sustained snowmelt, perennial springs, or both. They are usually physically connected by permanent streams, providing continuous (if one-way) conduits for transport of aquatic migrants. Zooplankton species representation in high elevation sites is uniform within catchments (among ponds) and across time (but is less so for between-watershed comparisons). This pattern holds true also for intraspecific comparisons based on the structure of select portions of the nuclear genome, such that genotypes are indistinguishable among basins with direct lotic connections. Mid- to low-elevation (500-1500 m) sites are usually ephemeral and are inundated by unpredictable rain and snowfall with associated runoff. Species and gene representation may be homogenized during spates but communities diverge during irregular intervals of drought and resulting isolation. Arid-land lentic communities and populations are therefore strongly affected by the degree of lotic connectivity among basins, though differing with respect to elevation and short-term climatic variation.