predators & biodiversity
TRANSCRIPT
Why is large carnivore’s conservation crucial?
Hélène BOULLOCHE-SABINE, Master 1 Biodiversité et écosystèmes tropicaux. 06 92 23 82 02. [email protected].
With this conceptual model of trophic cascade, we can notice the essential role of predators’
regulation. They are the key to preserve the equilibrium of ecosystems and to maintain
biodiversity.
William J. Ripple is a distinguished
professor of Ecology and a widely
published researcher. He works at the
Oregon State University in the
Department of Forest Ecosystems and
Society. He is best known for his
research about trophic cascades,
particularly about gray wolf’s role in
North America (Canis lupus).
In the United States, an eradication campaign removed many top predators of the ecosystem: Black Bears,
Grizzly Bears, Lynx, Cougars and Wolves. By the 1930’s, most of the states had recorded their last wolves.
After this lack of top predators, Yellowstone’s Aspin had apparently stopped growing and the global
ecosystem started being completely imbalanced.
The first wolves came back to Yellowstone (Wyoming) in 1995 after 70 years of absence.
Since their reintroduction, vegetation started to grow again by reducing herbivore’s population.
Reintroduction of grey wolves in Yellowstone
The reappearance of trees (Aspen) drove the reappearance of
many associated species: important song birds, beavers that
created fish habitats, amphibians… “Top predators affect so
many part of the ecosystem, their presence is crucial”, B. Ripple.
Hélène BOULLOCHE-SABINE, Master 1 Biodiversité et écosystèmes tropicaux.
06 92 23 82 02. [email protected].
The Cougar’s case in the United States of America
As many top predators in the world, cougars
have been considered by humans as ferocious,
dangerous and useless beast for decades. Their
eradication had disastrous consequences and
catastrophic regime’s modification in the Zion
National Park.
Increases in human visitors in Zion
Canyon
Reduction of Puma concolor densities
Higher mule deer (Odocoileus hemionus)
densities
Reduce recruitment of riparian
cottonwood trees (Populus fremontii)
Increase bank erosion
Reduction in aquatic and terrestrial
species abundance
Hélène BOULLOCHE-SABINE, Master 1 Biodiversité et écosystèmes tropicaux. 06 92 23 82 02. [email protected].
Bill Ripple and Robert Beschta bring with this study the evidence of
Eco-systemic services tops predators supply. It is necessary to conserve
those animals to conserve the feedback they fulfil on the whole
ecosystem. Without top predators, there’s no regulation, no
equilibrium and no biodiversity.
.
A world-wide issue to conserve global biodiversity
Many researchers of the world found it is the absence or the presence of top predators that affect the health of an
entire ecosystem. The decline of tops predators is happening at the same time in the entire world.
Coexistence between top predators and humans: Solutions exist
In France, the return of top predators such as Wolves and Lynx is in progress. If
public opinion relatively agrees with it, it’s not the same for farmers who are
really scared of the rivals’ return. An example in this picture where we can see
farmers in Lozère saying “Pastoralism and top predators are not compatible”.
Jean-Marc Landry, a Swiss ethologist, has been studying wolves for many years.
Finally, Solutions exist to protect the herds and to cohabit with those big
predators in the best conditions. The acceptation of Top predators stays a
political and a social problem. Protection dogs such as Patou are a very efficient
way to fight against top predators’ attacks.
Hélène BOULLOCHE-SABINE, Master 1 Biodiversité et écosystèmes tropicaux. 06 92 23 82 02. [email protected].
Distribution of the wolves in Provence, April 2014
Hélène BOULLOCHE-SABINE, Master 1 Biodiversité et écosystèmes tropicaux. 06 92 23 82 02. [email protected].
References
Scientific articles:
Beschta, R.L., Ripple, W.J. Large predators and trophic cascades in terrestrial ecosystems of the
western United States. Biol. Conserv. (2009), doi:10.1016/j.biocon.2009.06.015
Beschta, R.L., Ripple, W.J. Linking a cougar decline, trophic cascade, and catastrophic regime
shift in Zion National Park. Biol. Conserv. (2006). 397-408.
Ripple, W.J., Beschta, R.L. Trophic cascades in Yellowstone: The first 15 years after wolf
reintroduction. Biol. Conserv.(2011), doi:10.1016/j.biocon.2011.11.005
Videos:
https://www.youtube.com/watch?v=OFuajT_JHSA https://www.youtube.com/watch?v=PagO3gmwmA0 https://www.youtube.com/watch?v=3KHUMAQdSrw&list=PLHoLor_HYS1IUQQMlySXwqfMG3cdxDnwr&index=16
Pictures:
http://www.terrenature.ch/sites/default/files/styles/tn_article_main/public/images/articles/chien20div
aguantq011.jpg
http://www.devisrapide.com/photo/cloture-electrique2.jpg
http://etienne-et-reglisse.blogspot.com/2009/12/patou-des-pyrenees.html http://images.midilibre.fr/images/2013/08/23/les-eleveurs-defilent-contre-le-loup-en-
lozere_659998_510x255.jpg
http://www.ferus.fr/