Download Biodiversity and Restoration

Ecological Restoration (BIO 409)
Dr. McEwan
Lecture 5: Biodiversity and Restoration
Concept Review
Niche Complementarity: This is an idea about the relationship among species in
creating or perpetuating some ecosystem property. One way to illustrate this is to think
about species fitting together sort of like puzzle pieces. As you add species the
picture gets clearer…in the analogy, as you add species to the ecosystem, its
functionality increases accordingly. One example that is currently ‘hot’ is the idea that
as you add tree species to a forest, that forest’s capacity to capture and sequester
carbon increases.
This concept carries a whole load of assumptions with it…and it certainly has not been
clearly proven for all systems and/or all ecosystem functions. If Niche
Complementarity is occurring, you would expect a linear relationships between the
function and species diversity- as you add species- the function linearly increases.
One outstanding issue is whether (apparent NC) is because of increasingly filled niche
space or whether you just happen to pick up a species that is good at that particular
job as you add species (aka, Sampling Effect). This issue is very much alive in
Ecology right now.
Application for Restoration are obvious…
Concept Review
Functional Groups: There are a lot of
species in the world. A LOT. In many cases it
is very difficult, if not impossible, to address
this diversity from a scientific perspective,
much less from the perspective of
management. One way to simplify this
diversity is to focus on an individual’s
functions, rather than its taxonomy (i.e., its
evolutionary relationship to other organisms).
If you can “bin” species depending on function
then management or restoration could,
potentially, focus on functional groups. An
obvious example is aquatic insects which are
very often classified into functional groups
such as shredders, collector-gatherers, and
predators.
Concept Review
Species Redundancy: If we think about species as functional participants in
ecosystems- providing a specific capacity/outcome/function, it can lead to the idea
that some (or maybe even many) species are providing identical, or at least
measurably similar, attributes to the system.
Thus, the idea of species redundancy.
But, don’t think of this in a negative context…like there are useless species in an
ecosystem. No serious ecologist would hold such a myopic view.
Instead, thinking about it from this perspective allows the identification of species
that are MORE crucial to preserve/restore…those that provide a specific function
when no other species do. Some examples, for instance, N-fixing plants, or maybe
a shredding insect.
So as a restorationist, you could potentially focus on CREATING redundancy, to
make the restoration more stable.
Concept Review
Species Redundancy: If we think about species as functional participants in
ecosystems- providing a specific capacity/outcome/function, it can lead to the idea
that some (or maybe even many) species are providing identical, or at least
measurably similar, attributes to the system.
Thus, the idea of species redundancy.
But, don’t think of this in a negative context…like there are useless species in an
ecosystem. No serious ecologist would hold such a myopic view.
Instead, thinking about it from this perspective allows the identification of species
that are MORE crucial to preserve/restore…those that provide a specific function
when no other species do. Some examples, for instance, N-fixing plants, or maybe
a shredding insect.
So as a restorationist, you could potentially focus on CREATING redundancy, to
make the restoration more stable.
Diversity concepts
Biodiversity and Restoration: One of the most important questions
in ecology right now is about the relationship between diversity and
ecosystem function. Does changing diversity chance an ecosystem’s
functional capacity?
•Diversity and Disturbance
•Diversity and Productivity
•Diversity and Invasion
•Diversity and Ecosystem Function
Intermediate Disturbance Hypothesis
http://www.smithsonianmag.com/science-nature/victory-at-sea.html#
Intermediate Disturbance Hypothesis
Intermediate Disturbance Hypothesis, Applications for Restoration?
Productivity-Diversity Hypothesis
http://www.smithsonianmag.com/science-nature/victory-at-sea.html#
Diversity
Productivity
Measures of Diversity
Measures of Productivity
Here is an example from a paper that I am working on
right now. In this case the axes are flipped, biomass
on the y, diversity on the x. These are plots in forests
of Taiwan (see below). The idea here (and this is a
very definite application of the theory) is that we need
to understand whether more diverse forests store
more carbon. Management for “biodiversity” is
relatively common now, and management for “carbon
sequestration” is becoming an imperative of many
agencies. How do these two concepts fit together?
Are more forests also better at storing carbon?
Huston (1979) presented a generalized model:
The Dynamic Equilibrium Model of Diversity
http://www.smithsonianmag.com/science-nature/victory-at-sea.html#
How do disturbance and productivity
relate to one another?
The Dynamic Equilibrium Model of
diversity of Huston (1979). You read
this figure like a topographic map,
where the orange is the peak. So
there is a peak in diversity at
intermediate levels of both diversity
and productivity. In restoration
projects you may have gradients in
both productivity and diversity.
Diversity and Invasion:
This is a live argument in Ecology right now.
Some have argued that more diverse ecosystems should be LESS
susceptible to exotic invasion. Because niche space is all taken
up…the system is in effect “closed.” There have been a number of
studies providing support for this claim
http://www.smithsonianmag.com/science-nature/victory-at-sea.html#
Diversity and Invasion:
This is a live argument in Ecology right now.
Some have argued that more diverse ecosystems should be MORE
susceptible to exotic invasion. More diverse systems ususally occur
in what kinds of conditions (*hint, two slides back*). Those
conditions also promote invasion!
This debate is ongoing…no answer yet.
http://www.smithsonianmag.com/science-nature/victory-at-sea.html#
Is there a generalized relationship
between diversity and ecosystem
function in restoration?
Is there a generalized relationship between diversity and
ecosystem function in restoration?