PARENT SESSION
Poster Session 13: Landscape Ecology / Geomorphology
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Untangling matrix and patch quality effects on planthopper dispersal and spatial distribution.
Haynes, Kyle*,1, Dillemuth, Forrest2, Anderson, Bryan2, Hakes, Alyssa2, Jackson, Heather2, Cronin, James2, 1 Miami University, Oxford, OH, USA2 Louisiana State University, Baton Rouge, LA, USA
ABSTRACT- Two key factors influencing rates of herbivore movement among host-plant patches are patch nutritional quality and the type of surrounding habitat (matrix). These two factors are often correlated in nature; however their interactive effects on dispersal have not been studied previously. We performed a field experiment to investigate the independent and interactive effects of patch quality and matrix composition on dispersal of the planthopper Prokelisia crocea. Marked planthoppers were released onto experimental host-plant patches (prairie cordgrass) made to vary in matrix habitat (mudflat or brome) and plant nutritional quality. We found that these two factors had interactive effects on planthopper dispersal. In patches of low and medium nutritional quality, the emigration rate was 1.2 times higher for patches embedded in brome than mudflat. In contrast, the planthopper emigration rate was unaffected by matrix composition in nutrient-rich patches. Within matrix types, plant nutritional quality had little effect on the rate of planthopper emigration. In addition, a survey of cordgrass patches in nature revealed that the distribution of planthoppers was related to matrix composition and patch size, but not to plant nutritional content. Planthopper incidence and density increased with patch size and the percentage of the surrounding matrix composed of mudflat. We attribute the latter pattern to the planthoppers reluctance to emigrate from mudflat-bordered patches. Matrix effects on planthopper dispersal and spatial distribution may be stronger than patch quality effects because this highly fragmented system is dominated by small cordgrass patches and high rates of emigration.
Key words: landscape, metapopulation, movement, planthopper