Document Type
Article
Journal/Book Title/Conference
Second International Congress of Systematic and Evolutionary Biology
Publication Date
1-1-1980
First Page
56
Abstract
Results of a four-year study of the pollination ecology of a semi-arid desert scrub community in Catamarca Province, Argentina (27.3°S, 66.2°W) are reported. Sixty plant species, 22 annuals and 38 perennials, were included in the study. For each of these, data on floral characters, resources offered to flower visitors, flowering phenology, floral abundances and degree of dependence on pollen vectors for successful seed set were recorded. At the site, precipitation occurs almost exclusively as intense summer storms. Two major flowering peaks were observed. The first occurs during the dry spring and involves succulents and woody riparian perennials. The second follows the onset of the summer rains and involves most of the woody and herbaceous taxa. The woody flora is characterized by a low diversity of floral morphology with medium-sized, relatively unspecialized yellow or white flowers predominating. Although the flowers of the majority of the woody taxa are visited by a wide array of insects, the bulk of them are pollinated by a restricted set of solitary bees. Host specificity among the insects is only weakly correlated with their efficacy as pollinators. Approximately 20% (32 of 116 species) of the bees can be considered to be specialists, but only two genera of plants, Opuntia and Portulaca are largely dependent on specialists for pollination. None of the bees are specific at the species level. While some skew is evident, a high degree of overlap is evident in the flowering periods of the woody taxa. A specialized reward system of several of the dominant woody taxa require synchronous flowering with other plants sharing the same pollinators. Self compatibility is widespread in the flora, but only annual grasses and forbs appear to be regularly self-pollinating. Insect pollination systems, particularly those involving medium to large-sized bees, prevail. Wind pollination is restricted to grasses and one dicot. A single species is predominantly bird pollinated although hummingbirds play varying roles in the pollination of several taxa.
Recommended Citation
Simpson, B. B. and J. L. Neff. Pollination of a warm-temperate desert scrub community. Second International Congress of Systematic and Evolutionary Biology. Univ. British Columbia, July 17-14. 1980. p. 55