Open AccessLow genetic diversity and high inbreeding of the endangered yews in Central Himalaya: implications for conservation of their highly fragmented populations
Author(s) -
Poudel Ram C.,
Möller Michael,
Liu Jie,
Gao LianMing,
Baral Sushim R.,
Li DeZhu
Publication year - 2014
Publication title -
diversity and distributions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.918
H-Index - 118
eISSN - 1472-4642
pISSN - 1366-9516
DOI - 10.1111/ddi.12237
Subject(s) - ecology , genetic diversity , endangered species , population , biology , range (aeronautics) , effective population size , in situ conservation , allopatric speciation , population size , conservation genetics , genetic structure , geography , habitat , microsatellite , allele , biochemistry , materials science , demography , sociology , gene , composite material
Aim To assess patterns of genetic variation and levels of diversity in the endangered allopatrically distributed Taxus contorta , T. mairei and T. wallichiana in highly fragmented and degraded habitats of the Himalayas. Location Central Himalaya, particularly the area within the political boundary of Nepal and SW Xizang, China. Methods We used a multidisciplinary approach combining a transect study, population genetic analyses based on chloroplast DNA sequences and nuclear microsatellite data, and ecological modelling to estimate the size‐class structure, genetic diversity and differentiation of populations and understand the potential fate of yew populations in the face of rapidly degrading habitats and abrupt climate change. Results For all three species, the flat regression slopes of the size‐class distributions ( SCD ), and high permutation index values indicate unstable population structure with lower recruitment rates. The chloroplast and nuclear microsatellite data further reveal low genetic diversity, significant population differentiation and high inbreeding for yew species of this region. We identified two strong barriers of genetic discontinuities, where the presence of spatially different ecological environments caused an allopatric distribution of the species. The ecological model projection for the year 2080 forecasted a substantial decrease in size of suitable areas and a range shift towards the north. Main conclusions The spatial distribution of the genetic variation and diversity within and among the populations of each yew species was largely shaped by their peripheral position in their respective ranges, differences in their evolutionary histories, and the periodic and asynchronous climates experienced by the species, in addition to the severe impacts of anthropogenic activities. Several yew populations in Central Himalaya have already declined to sizes too small to be demographically sustainable. Improved conservation managements, both at the species and landscape levels, should be implemented for the protection of remnant populations.