Article Review:
Urban conservation genetics: Study of a terrestrial salamander in the city
Sarah Noël, François-Joseph LapointeDépartement de Sciences Biologiques, Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, QC, Canada H3C 3J7
Biological Conservation
Volume 143, Issue 11, November 2010, Pages 2823–2831
Although I have grown up with horses and enjoy the outdoors and open land, I am most definately a city girl. With the completion of this Herpetology class, I have gained a new understanding and respect for the reptiles and amphibians that not only live in our state, but also that live in my own backyard. I find it interesting how our growing population and urbanization affects our neighboring wildlife on even a chromosomal level. This article and subsequent research analyze the effects of urbanization on salamander genetic diversity, and reinforce the need for great habitat conservation efforts in order to reduce habitat fragmentation.
Researchers analyzed the genetic differentiation between Plethodon cinereus (Red-Backed Salamander) populations within the city of Montreal and two neighboring islands in the St. Lawrence River in Canada. 10 populations of salamanders were collected from various locations on Montreal island including mature forrests within the urban matrix, parks in older developed areas close to downtown that have been interrupted by human development since the 18th century as well as from newer urban areas. Two other population samples were collected from the neighboring islands of Ile-Bizard and Ile-Perrot.
Approximately 1 cm was cut from the tail of each of the sample salamanders collected, and they were released back to the location they were collected. The tail samples were used in order to extract DNA to perform various geneotypic and phenotypic analysis. Morphological characteristics were recorded in order to evaluate population diversity.
Researchers found that striped salamanders were the predominant characteristic in all of the sample populations, except those of Ile-Bizard, where the predominant color phase was lead-backed. On Montreal island the mean number of alleles within a population was 23.3, the mean inbreeding coefficient was zero and no bottlenecks were seen in any population. Tests showed that most populations were differentiated. Results were different on the two neighboring islands, with Ile-Perrot having higher degrees of genetic diversity. Test show that the allelic frequencies from the islands were distinct from each other and from Montreal populations.
In layman's terms, the research shows that the populations on each of the three islands, and within most of the different segmented areas of Montreal, the salamander populations are genetically different from each other. Large bodies of water and habitat fragmentation has virtually cut off gene flow between most of the populations sampled. On Montreal island however, there is no defined barrier as to what would cut off gene flow, because some populations (even those far apart) were not differentiated.
Researchers are concerned because genetic diversity is greatly reduced in urban settings within populations usually through genetic drift and inbreeding. Inbreeding was not seen in any of the Red-Backed salamander populations, and this is thought to be due to behavioral kin recognition. The lack of genetic diversity withing the individual populations is thought to be a indicator of low probability of long term survival of the species in urban settings.
This research further highlights the need for greater habitat conservation acts especially within urban areas. The protection of forest habitats within cities is vital to the protection of wildlife worldwide.
1 comment:
How can genetic diversity be preserved in these small, isolated populations? Would habitat corridors be useful for salamanders with typically tiny home range sizes? What about translocation?
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