Avoidance by grazers facilitates spread of an invasive hybrid plant.
Biological invasions greatly increase the potential for hybridization among native and non-native species. Hybridization may influence the palatability of novel hybrids to consumers potentially influencing invasion success; however, the palatability of non-native hybrids relative to the parent species is poorly known. In contrast, studies of native-only hybrids find they are nearly always more palatable to consumers than the parent species. Here, I experimentally demonstrate that an invasive hybrid cordgrass (Spartina) is dramatically less palatable to grazing geese than the native parent species. Using field and aviary experiments, I show that grazing geese ignore the hybrid cordgrass and preferentially consume native Spartina. I also experimentally demonstrate that reduced herbivory of the invasive hybrid may contribute to faster spread in a California estuary. These results suggest that biological invasions may increase future opportunities for creating novel hybrids that may pose a greater risk to natural systems than the parent species.
Grosholz
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Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA. tedgrosholz@ucdavis.edu
D000818:Animals; D001362:Avoidance Learning; D002140:California; D017753:Ecosystem; D005518:Food Preferences; D005777:Geese; D006824:Hybridization, Genetic; D006109:Poaceae / Q000235:genetics*