Journal of Ecology and Environment

pISSN 2287-8327 eISSN 2288-1220

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Published online September 3, 2019
https://doi.org/10.1186/s41610-019-0131-6

Journal of Ecology and Environment (2019) 43:33

© The Ecological Society of Korea.

Sex-related demographics in two remnant populations of a dioecious tree Ilex cornuta (Aquifoliaceae): implications for conservation

Sookyung Shin1,2, Hakbong Lee1,3, Jei-Wan Lee2 and Hyesoon Kang1

Department of Biology, Sungshin University, Seoul, Republic of Korea; Department of Forest Bioresources, National Institute of Forest Science, Suwon, Republic of Korea; Gwangneung Forest Conservation Center, Korea National Arboretum, Pocheon, Republic of Korea

Correspondence to:Hyesoon Kang

Received: July 15, 2019; Accepted: July 24, 2019

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Abstract

Background

Dioecious plant species having both male and female plants have been investigated regarding sex-related characteristics such as sex ratio, sex-differential resource requirements, and spatial segregation of the sexes. Habitat loss and fragmentation are major threats to the survival of plant populations, but dioecious species are particularly more prone to such habitat degradation than non-dioecious species because of their dimorphic sexual system. We examined the sex-related demographics of two Ilex cornuta populations being different regarding land use history.>

Methods

During 2016–2017, we examined I. cornuta trees with a basal diameter ≥ 1.5 cm in the Yongsu-ri population (YS population) and the Gotjawal Provincial Park population (GP population). Plant sex (male, female, or unsexed) was identified. The tree size (basal diameter and height of the main stem), clonal production (the ramet numbers per genet), and vitality for each clone were measured. The associations between population, sex, tree size, clonal production, and vitality were examined using ANOVAs and contingency table analyses. Finally, point pattern analyses using O-ring statistics were conducted to assess spatial patterns.>

Results

Upon excluding unsexed trees, the YS population with 74 trees was significantly male-biased (0.66), while the GP population with only 26 trees had a 1:1 sex ratio. In both populations, males and females did not differ in tree size. Although the mean number of ramets differed significantly between populations, females tended to produce more ramets than males. The proportion of weak trees was significantly higher in the YS than in the GP population. Neither population showed evidence of spatial segregation of the sexes.>

Conclusions

The two populations of dioecious I. cornuta are characterized by the small number of trees and relatively high frequencies of non-reproductive trees. Both indicate that these populations are quite susceptible to environmental and genetic stochasticity. On the other hand, the differences between populations in sex ratio, clonal production, and vitality suggest that conservation efforts for I. cornuta need to be population-specific. In order to help recover and enable this vulnerable species to persist, it is necessary to find ways to enhance their sexual reproduction and simultaneously reduce habitat disturbances due to anthropogenic activities.

Keywords: Conservation, Dioecy, Ilex cornuta , Sex ratio, Sex-related spatial structure

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Journal of Ecology and Environment

pISSN 2287-8327 eISSN 2288-1220