Biodiversity loss and its impact on humanityCardinale 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 2013In 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 p60This 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 birdsCoyotes 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 yield-although 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?