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Patterns of allozyme diversity in the threatened plant Erigeron parishii (Asteraceae)
Author(s) -
Neel Maile C.,
Ellstrand Norman C.
Publication year - 2001
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2657033
Subject(s) - biology , asteraceae , threatened species , botany , genetic diversity , evolutionary biology , ecology , population , demography , habitat , sociology
Thirty‐one occurrences of Erigeron parishii , a narrowly endemic plant threatened by mining, were sampled for allozyme diversity. This taxon held considerable genetic variation at the 14 allozyme loci surveyed. Species (e.g., alleles per locus [ A ] = 4.3 and proportion of polymorphic loci [P] = 0.64) and population (e.g., A = 2.15 [SD = 0.3] and P = 0.53 [SD = 0.12]) genetic diversity measures were higher than expected for narrowly endemic plant taxa. The proportion of polymorphic loci and numbers of alleles per locus indicated that E. parishii has not experienced severe or long‐lasting population bottlenecks. Within‐population f indicated low to moderate levels of inbreeding. Populations were only moderately differentiated (theta‐p = 0.12), suggesting either that there is substantial gene flow among populations or that populations have not been isolated long enough to detect effects of genetic drift. There was no significant differentiation among populations in different vegetation types nor was there a relationship between genetic distance and geographic distance among sites. Continued fragmentation by mining activities would isolate populations, disrupting gene flow, exacerbating loss of diversity, and increasing inbreeding in the remaining fragments. Protection of large, interconnected populations throughout the range of the taxon is warranted to maintain processes that have sustained the observed diversity.