(Georgia Institute of Technology, 1983-12)
Hay, Mark E.; Goertemiller, Tim
Transplanted sections of the seagrass Thalassia testudinum were used as a
bioassay to assess between-habitat differences in herbivory on three Caribbean
reefs. Consumption of Thalassia by herbivorous fishes on shallow (1-10 m) reef slopes was significantly higher than on deep (30-40 m) reef slopes or on shallow
reef flats. Seaweeds typical of reef flat habitats were rapidly consumed when
placed on shallow reef slopes. Seaweeds typical of either deep or shallow reef
slopes were relatively resistant to herbivory and a high proportion of these
species are known to contain secondary chemical compounds that appear to deter
herbivorous fishes. Shallow reef flats provide seaweeds with a predictable
spatial escape from major reef herbivores; algae characteristic of these habitats
have evolved few, if any, characteristics that significantly reduce losses to herbivory.
(Georgia Institute of Technology, 1983-08)
Fuller, Patricia J.; Hay, Mark E.
With a few notable exceptions (Borchert and Jain 1978, Inouye et at. 1980, O'Dowd and Hay 1980, Hay and Fuller 1981), most ecological studies on seed-granivore interactions in arid communities have concentrated on the adaptations and ecology of the granivores and not on characteristics of the seeds that may deter granivory. Since a large portion of the annual seed crop of many desert ephemerals is lost to seed predators (Chew and Chew 1970, French et al. 1974, Nelson and Chew 1977, Brown et al. 1979), characteristics that significantly reduce losses to granivores should be strongly selected. In this paper we show that under natural conditions seeds of the desert annual Salvia columhariae produce a glue-like substance when wetted that strongly binds sand grains to the seeds, and that seeds thus covered by sand suffer significantly less loss to desert granivores.