Abstract
BackgroundIn most regions of the world human influences on the distribution of flora and fauna predate complete biotic surveys. In some cases this challenges our ability to discriminate native from introduced species. This distinction is particularly critical for isolated populations, because relicts of native species may need to be conserved, whereas introduced species may require immediate eradication. Recently an isolated population of seal salamanders, Desmognathus monticola, was discovered on the Ozark Plateau, ~700 km west of its broad continuous distribution in the Appalachian Mountains of eastern North America. Using Nested Clade Analysis (NCA) we test whether the Ozark isolate results from population fragmentation (a natural relict) or long distance dispersal (a human-mediated introduction).ResultsDespite its broad distribution in the Appalachian Mountains, the primary haplotype diversity of D. monticola is restricted to less than 2.5% of the distribution in the extreme southern Appalachians, where genetic diversity is high for other co-distributed species. By intensively sampling this genetically diverse region we located haplotypes identical to the Ozark isolate. Nested Clade Analysis supports the hypothesis that the Ozark population was introduced, but it was necessary to include haplotypes that are less than or equal to 0.733% divergent from the Ozark population in order to arrive at this conclusion. These critical haplotypes only occur in < 1.2% of the native distribution and NCA excluding them suggest that the Ozark population is a natural relict.ConclusionOur analyses suggest that the isolated population of D. monticola from the Ozarks is not native to the region and may need to be extirpated rather than conserved, particularly because of its potential negative impacts on endemic Ozark stream salamander communities. Diagnosing a species as introduced may require locating nearly identical haplotypes in the known native distribution, which may be a major undertaking. Our study demonstrates the importance of considering comparative phylogeographic information for locating critical haplotypes when distinguishing native from introduced species.
Highlights
In most regions of the world human influences on the distribution of flora and fauna predate complete biotic surveys
We find that the highest genetic diversity in D. monticola is restricted to a localized region (< 2.5% of the distribution) in northern Georgia, and a correct diagnosis of the Ozark population is highly dependent on including critical haplotypes from this region in the Nested Clade Analysis (NCA)
Our analyses of mitochondrial DNA indicate that the highly disjunct population of seal salamanders, Desmognathus monticola, recently discovered on the Ozark Plateau, is not native to the region. This population may need to be extirpated because of its potential negative impacts on endemic Ozark stream-dwelling salamanders. This conclusion could only be realized once nearly identical haplotypes from the known native distribution were included in our analyses
Summary
In most regions of the world human influences on the distribution of flora and fauna predate complete biotic surveys In some cases this challenges our ability to discriminate native from introduced species. Humans have been altering biotic patterns across the world since the "Age of Exploration" [7], and for many regions species introductions precede complete biodiversity inventories, obscuring our ability to distinguish introduced from native flora and fauna. This is potentially a very important yet time sensitive distinction, especially for isolated populations, because the alternate diagnoses suggest opposite conservation action. We show that using comparative phylogeographic patterns of taxa that are co-distributed across the known, native range of a putatively introduced population may be the most effective strategy for distinguishing native from introduced species
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
