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Andrea Rose Cadiz
Biology Lab 1615
Professor Judy Bunkall
Article Summary
Rare Species Support Vulnerable Functions in High Diversity Ecosystems
In this generation, we often think that rare species are no longer needed or useful.
However, they do affect amongst other life factors. They offer more than aesthetic, cultural, or
taxonomic, diversity value. In turn, they are highly vulnerable due to overexploitation, habitat
loss, competitive interactions with wild species, and climate change (Mouillot et al., 2013, 1).
They are also contributed mainly the ever increasing anthropogenic pressures on ecosystems.
This article, shows the importance among rare species who are thought to be highly redundant
since they are, unfortunately, the first one to disappear. Rare species were considered to have
little influence on the functioning of an ecosystem compared with more common species. This
circumstance is known as functional redundancy meaning that they have the same ecological
roles as those common species but have less impact because of their low abundance (Public
Library of Science, 2013). They Also, datasets of local abundance, regional occurrences, and
functional traits from three highly diverse ecosystems (coral reef fishes, alpine plants, tropical
trees) are demonstrated to initiate whether rare species could be protected from its loss of
functions (Mouillot et al., 2013, 1).
The researchers analyzed whether rarer species in three different ecosystems performed
the same ecological functions as the most common ones. They tested 846 reef fish, 2979 alpine
plants and 662 tropical trees and found that most of the unique and vulnerable functions goes
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along with rare species. They divided “rareness” in two categories, rare and rarest, which was
deliberated between local abundance and regional scale; and between regional scale and
functional distinctiveness (Mouillot et al., 2013, 3).
For the three data sets, regional rare species were defines as those with a regional
occupancy of less than 5% of the maximum observed value across the species pool, while
the regional rarest species were with only one occurrence. For reef fish and tropical trees,
the local rarest species were defined as those with an average of one individual by sample
where present, while for alpine plants the rarest threshold was set at less than 1% of the
maximum observed cover. The locally rare species were defined as those with less than
5% of the maximum observed local abundance, less than 1.5 individuals for reef fish, less
than 4.4 % maximum cover for alpine plants, an less than 2.4 individuals by plot for
tropical trees (Mouillot, 2013, 8).
For functional distinctiveness, first they used the functional traits, then a dendogram, then they
finally adapted the Evolutionary Distinctiveness index that is able to measure species relative
contributions to phylogenetic diversity, which is the evolution of a genetically related group of
organisms as distinguished from the development of the individual organisms. The
distinctiveness of a species is simply the sum of these values for all branches. This how they
were tested whether they were disproportionately represented along the gradient in their
functional vulnerability (Mouillot, 2013, 8).
Dr. Mouillot (2013) suggests that the loss of these species could heavily impact upon the
functioning of their ecosystems. He said that rare species were more vulnerable and have a very
irreplaceable functions for the preservation of biodiversity as a whole, not just for the most
common species but all those who perform vulnerable functions, appears to be crucial for the
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resilience of ecosystem (Public Library of Science, 2013). Their results call for new approaches
like to scale up our results from the one-trait one-function perspective to a more sophisticated
multifunctionality perspective, to disentangle the relative contribution of rare and common
species traits to complex ecosystem properties. Their results indicate that rare species may
deliver more unusual and important functions than their local abundance or regional occupancy.
This indicates that even in highly diverse systems, they can no longer assume that rare species
can be discounted by the high probability of functional redundancy. Meaning that rare species is
as important as their more common counterparts (Mouillot, 2013, 6).
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References
Mouillot, D., Bellwood, D., Baraloto, C., Chave, J., Galzin, R., Harmelin-Vivien, M., . . . Mace,
G. (2013). Rare Species Support Vulnerable Functions in High-Diversity Ecosystems.
PLoS Biology, 11(5), E1001569-E1001569.
Public Library of Science. (2013, May 28). Rare species perform unique roles, even in diverse
ecosystems. ScienceDaily. Retrieved April 6, 2015 from
www.sciencedaily.com/releases/2013/05/130528181028.htm