Abstract Detail



Reticulate evolution and biogeography in ferns and lycophytes - a colloquium honoring Dr. David Barrington

Bauret, Lucie [1], Schneider, Harald [1].

Assemblage analysis of karst species in Southeast-Asia: is the colonization of karst a random process for ferns?

Karst refers to environments with specific landscapes generated by water erosion and composed of carbonate-rich rocks like limestone. Thanks to this erosion, karsts offer highly structured landscapes, with cracks, sinkholes, cockpits, and rock towers. Many karst taxa are characterized by specializations, thanks to adaptation to unique local conditions including soils with high concentration of calcium and/or magnesium, poor and nutrient-deficient soils, dry conditions, and diverse micro-habitats. In Southeast-Asia and especially in South China, we find arguably the largest tropical karst formation. Unfortunately, these karsts are threatened by human activities, mainly due to limestone quarrying. It is then urgently required to study these environments to assess their importance in the assemblage of diversity in the Indo-Burma biodiversity hotspot. The roles played by karst systems in the evolution of fern diversity in tropical areas has not been inferred. Ferns are in general considered to be limestone avoiders as reflected in the low frequency of limestone specialists among the global species diversity. However, some genera are exceptionally well represented in karsts. Genera such as Asplenium, Adiantum, Cyrtomium, Polystichum, Tectaria, and Hypodematium have between 25-60% of their diversity occurring in karst. These observations lead us to assume that colonization of karst is not a random process and that interesting evolutionary and ecological processes have impacted the evolution of ferns in Southeast Asian karsts. However, this needs to be properly tested at a large macroevolution scale. We aim here to present the results of an assemblage analysis of fern species in karst of continental South-East Asia. This analysis will test the hypothesis that karst fern diversity is not randomly distributed in the phylogeny of ferns. The calculation of indexes on its phylogenetic structure will enable us to elucidate the processes leading to their current biodiversity and help us to target the next steps in the study of these peculiar karst lineages in the evolution of ferns.


1 - Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Center of Integrative Conservation, Menglun, Yunnan, 666303, China

Keywords:
Assemblage of species diversity
phylogeny
Southeast Asia
Karst
ferns.

Presentation Type: Colloquium Presentations
Number: 0004
Abstract ID:313
Candidate for Awards:Margaret Menzel Award,Edgar T. Wherry award


Copyright © 2000-2019, Botanical Society of America. All rights reserved