PARENT SESSION
Oral Session # 91: Biogeography III: Aquatic Communities.
Presiding: B Taylor
Friday, August 8. 8:30 AM to 12:00 PM, SITCC Meeting Room 103.
Consistency of fish species associations in stream pools: Implications for local coevolution.
Matthews, William*,1, Marsh-Matthews, Edie1, 1 University of Oklahoma, Norman, OK
ABSTRACT- Consistent patterns in contacts between species should promote coevolution of species traits. Coevolutionary interactions have been assumed to require long periods of intimate contact between species, but recent evidence shows that coevolutionary adjustments can occur within decades, making interspecific contacts in ecological time important in understanding trait changes in evolutionary time. The question of persistence of species contacts in ecological time has been largely ignored in the literature. Many studies have assessed changes in animal assemblages at fixed sites, but few have explicitly tested persistence of species associations in complex communities. We visually surveyed fish species, and size-structured ecospecies, on 11 dates from 1995 to 2002 in 14 pools in a perennial reach of a small stream, and calculated matrices of similarity in qualitative and quantitative contacts among taxa on each date. We then used Mantel tests to assess consistency of contact patterns between surveys at intervals of months and years, and across four physical disturbances (floods and droughts). We used data from similar surveys in 1982-1983 to test long-term consistency in species associations. Associations of species and ecospecies associations in direct contact were consistent across many, but not all, intervals between surveys and were highly consistent between decades. Such consistency of contacts among these taxa could promote coupled coevolution between species pairs or diffuse coevolution within the community, and may be applicable to a broader geographic mosaic model of coevolution that has been proposed in recent literature.
Key words: stream fish, species associations, coevolution