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LATITUDINAL DIFFERENCES IN PLANT PALATABILITY IN ATLANTIC COAST SALT MARSHES
Author(s) -
Pennings Steven C.,
Siska Erin L.,
Bertness Mark D.
Publication year - 2001
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(2001)082[1344:ldippi]2.0.co;2
Subject(s) - herbivore , palatability , ecology , biology , salt marsh , predation , plant community , marsh , growing season , species richness , food science , wetland
A central hypothesis of biogeography is that consumer–prey interactions are more intense at lower latitudes, leading to increased defenses of prey. Because plants vary in many traits that might affect palatability to herbivores, however, studies of latitudinal variation in single plant traits such as secondary chemistry provide only circumstantial evidence to test this hypothesis. We directly compared the palatability of 10 salt marsh plants from seven northern (Rhode Island and Maine) and eight southern (Georgia and Florida) coastal salt marshes by flying fresh plant material back and forth and allowing 13 species of herbivores direct choices between northern and southern conspecific plants in laboratory assays. In 127 of 149 assays (85%), herbivores showed a significant or marginally significant preference for northern plants. In only one assay did herbivores prefer southern plants. These results occurred regardless of the geographic location of the assay, herbivore species, year, or season of plant collection, although there were hints that latitudinal differences became less pronounced for two plant species late in the growing season. Our results provide the most comprehensive evidence to date for a latitudinal gradient in plant palatability in any community. The proximate plant traits and the ultimate evolutionary factors responsible for this pattern remain to be determined.