Diversity within species...The portfolio effect

[Gloria]

A look at the sockeye salmon populations of Alaska's Bristol Bay shows diversity among local populations keeps survival high.



Taking Stock in Diversity: Species with a Varied Population "Portfolio" Thrive: Scientific American

School of Aquatic and Fishery Sciences think they know why Bristol Bay is so productive year after year: Several hundred discrete populations of sockeye salmon inhabit the network of rivers and lakes that empty into the bay, and this tremendous population diversity buffers the entire fishery against the vicissitudes of the environment.

The portfolio effect is also expected to help species adapt to climate change.

[Gloria]

Differences within a species subtle but important to species gene survival and the ecosystem

National Geographic News


Intraspecies Diversity Helps Ecosystems, Study Says

study was conducted on a turkey oak (Quercus laevis Walter) sandhills community at UGA's Savannah River Ecology Laboratory in Aiken, South Carolina, where Madritch and Hunter analyzed the decomposition of nine different single-tree litter treatments and one mixed treatment that contained litter from all nine trees of the same species. They found a marked difference in the amount of carbon and nitrogen released based upon the parentage of the leaf litter.

Single-tree litter treatments did not always yield less carbon and nitrogen than the mixed treatment. Sometimes the single-tree treatments produced more nutrients and sometimes they produced less, but the researchers say the nutrients were always significantly different than the mixed-litter treatment.

"The alarming part of this discovery is that you cannot predict the effect that reduced genetic biodiversity will have on an ecosystem," said Hunter. "Therefore, deforestation is like playing Russian roulette with our future.

Mike Madritch, an ecology doctoral student at UGA.
co-authored with Mark Hunter, associate professor of ecology at UGA, and published in the Ecological Society of America's journal, Ecology. The research was funded by the National Science Foundation and the Andrew W. Mellon Foundation.

[Gloria]

California Environmental Resources Evaluation System an 80 page report with some interesting questions.
ceres
http://ceres.ca.gov/snep/pubs/web/PDF/VII_C28.PDF

Evaluation of significant risks to gene pools including intra species diversity in the sierra nevada ecosystem.

Habitat alteration,destruction,degradation or fragmentation
Severe wildfire
Silviculture activities...
manipulating individuals and populations,tree improvment programs, operational forest regeneration and timber harvest
Ecological restoration...
practitioners of ecological restoration have only recently become aware of genetic concerns in planting.. Understanding of the appropriate genetic material within species, its origin,diversity and collection, remains missing or rudimentary in many programs

Questions...

What important compositional, structural and functional genetic diversity exists,
How much, what kind and what distribution of genetic diversity is desired or enough,
How do human activities affect, both directly and indirectly,genetic diversity detrimentally, and what actions can be taken to prevent or mitigate undesired consequences?

Deborah L. Rogers
Constance I. Millar
Robert D. Westfall

[dapjwy]

Great info, Gloria, thank you for sharing it.

Reading this made me think again about whether it is so bad to grow native plants from areas farther than the recommended 10-50 mile radius that I've heard/read.

I do want to preserve unique features of local communities, but I'm not so sure that I have to be so concerned that I brought New England aster here from Western PA, only to find a few growing on the edge or my property here in NE PA with which they will interbreed.