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Biodiversity loss and its impact on humanity
Cardinale et al. 2012
Under a brief history…..
Certain life forms can substantially alter the
structure and functioning of whole ecosystems.
How?
Historically we have known communities are
important because we have ….
• Ecosystem Engineers
• Trophic Cascades
• Keystone Species
What are these things?
Can you come up with examples?
Google?
Callan et al 2013
In a three-level food chain, an increase in carnivores causes a decrease
in herbivores (i.e.: deer, elk, etc.) and an increase in primary producers
(i.e.: plants).
For example, in eastern North America the removal of wolves (Canis
lupus) has been associated with an increase in white-tailed deer and a
decline in plants eaten by the deer.
There is clear evidence that the presence of wolves is associated with a
trophic cascade of events. …..the absence of the top predators can have
pervasive impacts on the native plant communities in Wisconsin.
In general, places occupied by many wolves had a diverse understory
community (forest floor) with varied kinds/sizes of vegetation. In
contrast, places with few wolves were characterized by a very limited
herbaceous layer (plants that are fleshy and wither after the growing
season) and almost no woody-browse (i.e. trees). - See more at:
http://wolfwatcher.org/2013/06/new-research-confirms-wolves-trigger-a-trophic-cascade-wisconsin/#sthash.MtAw5atE.dpuf
Keystone species
Biodiversity (Rio Earth Summit 1992 started
interest).
Initially more interest in BEF…
Look in the right hand column of first page…How
are the approaches different?
BEF* vs BES…
What are these things????
Can you make a Venn diagram to describe the relationship
between them?
What are the different BEFs and BESs (look at Box 1 and
Table 1)?
For BES what is the difference between provisioning and
regulating?
What “level” of biodiversity is missing in Box 1?
*Note term ecosystem processes (basically same as
ecosystem function)
BEF p60
This section has 6 “consensus statements.”
1. Biodiversity loss reduces the efficiency by
which ecological communities capture biologically
essential resources, produce biomass, decompose
and recycle biologically essential nutrients.
What does this mean? Did we look at any graphs
on “efficiency”?
2. Biodiversity increases the stability of
ecosystem functions like total biomass through
time.
Why?? (think about investing in stocks)
Portfolio effect….
http://www.nature.com/scitable/knowledge/library/biodiversity-and-ecosystem-services-is-it-the-96677163
http://www.nature.com/scitable/knowledge/library/biodiversity-and-ecosystem-services-is-it-the-96677163
http://www.nature.com/scitable/knowledge/library/biodiversity-and-ecosystem-services-is-it-the-96677163
http://www.nature.com/scitable/knowledge/library/biodiversity-and-ecosystem-services-is-it-the-96677163
3. The impact of biodiversity is nonlinear and
saturating such that change accelerates as
biodiversity loss increases.
But what did the Reich article show?? (it is newer)
3. The impact of biodiversity is nonlinear and
saturating such that change accelerates as
biodiversity loss increases.
But what did the Reich article show?? (it is newer)
4. Diverse communities are more productive because
they contain key species that have a large influence
on productivity and differences in functional traits
increase total resource capture.
What are functional traits??
There have been controversies over ..
selection/sampling effects vs complementarity?
What do we mean by these terms??
Selection/sampling=big effect from having added a
single species to the mix (big bluestem)
Now we know it is likely a little of both!
“Plant communities are like a soccer team. To win
championships, you need a star striker that can
score goals, but you also need a cast of supporting
players that can pass, defend, and goal tend.
Together, the star players and supporting cast
make a highly efficient team.” Lars Gamfeldt
http://www.imachordata.com/diversity-it-matters-for-plants/
5. Loss of higher consumers can cascade through a
food web to influence plant biomass.
Trophic
cascades!
Foxes eat mice and small birds
Coyotes like squirrels and
rabbits.
So which of these is increasing
in this part of MN?
Levi and Wilmers 2012
EMERGING TRENDS…..!!
1. Biodiversity loss might be as important as other
major drivers of global change like climate change.
2. Effects of biodiversity loss likely grow stronger
over time (did we see this?? Reich paper!)
3. Whenever you look at maintaining multiple
ecosystem processes (like biomass production and
decomposition) you need even more biodiversity.
The BES section is set up very differently (p62).
CERTAIN services are directly or strongly
correlated with biodiversity (Statement 1).
Example/s would be? (LOTS)
MANY services show a mixed pattern (Statement 2)
Example would be..? (Intercropping, long term
carbon storage, plant div and pest abundance)
SOME services have insufficient data (Statement 3).
Example would be…(fish diversity and fish yieldalthough are more stable, biodiversity and flood
regulation) “surprisingly literature has said this
relationship exists…”
A SMALL NUMBER show a pattern in the
opposite direction!
Greater diversity of bacterial pathogens are bad.
• Which curve suggests many species can perform
the same function?
• Which curve shows every species is equally
important?
• Which curve shows species work
synergistically?