Create your own conference schedule! Click here for full instructions

Abstract Detail

Patterns and Processes of American Amphitropical Plant Disjunctions: New Insights

Saunders, Kelsey [1], Schenk, John J. [1].

Determining long-distance dispersal modes in amphitropically distributed species through adaptive diaspore structures.

A repeated pattern of amphitropically disjunct species or sister species distributed on either side of the equator has long-fascinated botanists, but the modes of these disjunctions have been debated. To determine the modes of long-distance dispersal, we evaluated diaspore morphology to identify probable dispersal mechanisms. We investigated the sizes and structures associated with dispersal in fruits, seeds, or spores for 134 species from 42 families. Among angiosperms, seeds were the dispersing propagules in 23% of the species, whereas 77% were dispersed as fruits. Our preliminary assessment identified that diaspores were dispersed endozoochorously (10%), exozoochorously (73%), and anemochorously (17%), but not hydrochorously (0%). An analysis of variance revealed that diaspores associated with endozoochory were on average 7 mm larger than exozoochorous and anemochorous diaspores (P < 0.001), but no significant difference between the latter two. Structures involved with exozoochory included hairs, barbs, or burrs in fruits, and hairs or gelatinous surfaces in seeds. Anemochory involved winged seeds, pappus, or spores in ferns. Botanists have long-held the assumption that bird migrations are responsible for amphitropical disjunctions. Among angiosperms, our results support this assumption, with the majority of these events occurring by external attachment of small fruits. However, our results also indicate that wind dispersal might play a greater role in producing amphitropical distributions than previously thought, and at a greater rate than endozoochory or hydrochory.

Log in to add this item to your schedule

1 - Georgia Southern University, Department of Biology, 4324 Old Register Road, Statesboro, GA, 30458, USA

dispersal mechanisms
long-distance dispersal
intercontinental discontinuous distribution
Amphitropical distribution

Presentation Type: Colloquium Presentations
Session: C2, Patterns and Processes of American Amphitropical Plant Disjunctions: New Insights
Location: 204/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 3:45 PM
Number: C2009
Abstract ID:292
Candidate for Awards:None

Copyright © 2000-2016, Botanical Society of America. All rights reserved