Abstract Detail


Liu, Yunpeng [1], Heberling, Mason [2], Wang, Zhiheng [3], Soltis, Douglas [1], Soltis, Pamela [4].

Addressing Darwin’s naturalization conundrum using native and naturalized species using disjunct genera that occur in Eastern North America and Eastern Asia.

Darwin’s naturalization conundrum is one of the central issues in invasion biology. Exotics closely related to natives may be hard to naturalize, because of the intense competition induced by high degree of niche overlap (I.e., the Darwin’s naturalization hypothesis). Alternatively, close relatives prefer similar environments, and thus exotics are under less environmental pressure in the habitats occupied by their closely related natives (i.e., the Preadaptation hypothesis). Numerous studies have been conducted to test the two hypotheses at community level and focus on the relationship between phylogenetic relatedness, the success of exotics and coexistence with natives. While it is unclear the tradeoff exotics experience during naturalization between 1) avoiding competition by decreasing overlap with closely related natives in climatic niche and distributions; and 2) colonizing habitats that allow successful naturalization with the smallest niche changes. Species from disjunct genera distributed in separated regions that are closely related supply wonderful materials for testing Darwin’s naturalization conundrum. Eastern Asia (EA) and Eastern North America (ENA) have similar climate gradients and share numerous closely related species; many genera (e.g., Magnolia) that span the EA-ENA disjunction have been transported intentionally or accidentally in the last 400 years. Here, using the distribution data and phylogenies of EA-ENA disjunct genera, we compared both ecological niches and distributions among native and naturalized species in ENA and evaluated the changes of exotics in both climatic niche and geographical range size during naturalization. We found 15 out of 65 disjunct genera that contain both native and naturalized species in ENA. Within these genera, the original EA niche space of the EA species that are naturalized in ENA did not show significant differences with their closely related ENA natives. However, the naturalized populations in ENA showed a shift in niche compared to plants in EA. We hypothesize that the strong effect of competition may have promoted both rapid niche changes and distributional divergence during the process of naturalization. Interestingly, most of the naturalized species have narrower niche breadths and geographical range sizes than their original distribution in EA, and this is still true when considering the introduced time. This may indicate that competition exclusion may be more important than preadaptation or enemy release for exotics from disjunct genera. Our results support Darwin’s naturalization hypothesis and supply valuable insights on evaluating the intercontinental biotic invasion risk underlying the floristic exchanges among disjunct species.

1 - University of Florida, Florida Museum of Natural History,, 3215 Hull Road, P. O. Box 2710, Gainesville, FL, 32611, USA
2 - Carnegie Museum Of Natural, Section Of Botany, 4400 Forbes Ave, Pittsburgh, PA, 15213, United States
3 - Peking University, College Of Urban & Environmentl Sciences, 5 Yiheyuan Road, Haidian District, Beijing, 11, 100871, China
4 - University Of Florida, Florida Museum Of Natural History, Gainesville, FL, 32611.0, United States

Eastern Asia – Eastern North America floristic disjunction
Plant invasion
Climatic niches.

Presentation Type: Oral Paper
Number: BIOG I003
Abstract ID:142
Candidate for Awards:None

Copyright © 2000-2022, Botanical Society of America. All rights reserved