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Chat Meeting 2
Up to Project Ideas
I got the impression during the chat that there was still quite a lot of confusion about the idea I originally posted (and which we subsequently modified). I have no problem abandoning it (or modifying it further), but it would be a shame for this to happen due to my inability to explain it properly.
In the most general sense, we want to be able to say something about managing linear habitats in such a way as to maximize on and off farm services; essentially finding a balance between the two, as they will sometimes be in conflict.
We expect that some species & sets of species are more likely to perform on farm services than others, based on their ability/desire to forage/hunt in agricultural fields. For plants, we expect some species to provide better nesting/foraging habitat for these species than others.
Given the confines of what is a linear habitat in an agricultural setting, what kind of habitat should we be trying to create? What should we be trying to emulate?
One thought is to create habitat that most closely resembles a natural habitat type that is rich in species and contains species comfortable in open areas, i.e., edge or scrub/secondary growth species. The exact definition of this will vary by region.
But if we have information on what characterizes this habitat type for each region (be it species composition or structural complexity or presence of certain functional groups), we can then compare the information we have on linear habitats in each region to this. It gives us a benchmark with which to judge the success or utility of management techniques within each region [i.e., "Management technique A results in a community that most closely resembles naturally occuring edge communities in Central America. This community has the following beneficial characteristic (blah blah blah). However, these linear habitats have a much higher percentage of non-native species and therefore would require targetted removal to mitigate the negative off-farm services related to the spread of invasives"]. At the same time, this comparison between natural and LH habitats gives us a unifying framework to pull together the individual analyses in all regions.
And it also gives us the ability to look at the relevance of secondary growth/scrub habitats at the lanscape level by looking at the relative predominance of this habitat type in each region we are looking at. For example, if a particular technique for planting and managing filter strips in the midwestern U.S. creates habitat that most closely resembles native Prairie communities (by some measure we define), the importance of this in terms of off-farm services is critical, since there is very little Prairie habitat in the lanscape. The linear habitat managed this way become all-the-more valuable if they are creating habitat that is rare in the lanscape.
In the end, this approach gives structure to our analysis. If we don't have a common benchmark to measure success in these diverse regions, then we then need to discuss each system separately (coming up with measures of success that are region-specific). Or come up with another benchmark to measure success....
Of course, there are problems and assumptions that people might not be comfortable with here. So fire away!
Re: Chat Meeting 2
Posted by
dtdalton
at
March 05. 2007
During our March 5th chat session we attempted to
specify the details of our project. We
elaborated on the ideas we discussed last week, as well as clarified our goals
for the project. Because a draft of our plan
is due early next week, our discussion was aimed to make progress toward
deciding our topic. Due to time
constraints, we were unable to decide on the topic during the session, so we
need to use the Discussion Board throughout the week to meet the deadline.
We covered a variety of issues this morning, which I have
summarized in the following four points.
- Maintenance
of hedgerows
Can hedgerows be planted and
maintained to optimize ecological services of associated species? How intensively should these LH’s be
managed? There may be some overlap with
the pest control group or the plant disease group. A point of clarification our group must work
on is to define our objectives, since goals influence management decisions.
- How
linear habitats mimic succession
Is there a particular successional
state which provides a favorable set of ecological services on and off the
farm? We discussed how we may approach a
comparative study between LH and how they may mimic ‘natural’ systems. For the scope of this project, it was
suggested that we compare habitats within the same region to pinpoint important
species or functional groups. We can
then generalize across regions if a particular management strategy is
effective.
- Structural
and functional aspects of habitats
Which habitats or successional
stages contain key species, and how can linear habitats be designed to
represent these species? A logical place
to start here would be to obtain background data showing species compositions
of linear habitats, disturbed and undisturbed natural areas, and cropland
adjacent to these areas. We decided to
avoid – for the most part – addressing pollution and erosion control aspects of
linear habitats.
- Compare
and contrast long-lived LH in tropical versus temperate ecosystems
We have live fence data from Central America, and some data for European hedgerow systems
are online. This aspect would require a
more extensive literature review but would be important to examine conclusions across
regions and habitat type.
I look forward to discussing these issues with you all
throughout the week.
-Danny
Danny, I think that you briefly mentioned LH restoration possibilities during our chat today. Did you want to discuss that a little more? Were you thinking of that as a separate approach altogether, or rather as another, more holistic form of LH management?
Feel free to run with this or not...
Re: Chat Meeting 2
Posted by
dtdalton
at
March 06. 2007
Let me attempt to better explain the restoration technique I was telling Sergio about. During a flooding event, material from a flood terrace can wash away, thus changing the condition of the soil within it and leaving land upslope of the stream in greater danger of erosion during subsequent floods. The land manager installed a linear habitat in the form of thick woody vegetation at the base of the terrace slope. His crew dug a shallow trench and placed 'wattles,' (tight bundles of healthy willow cuttings) upright so as to lean against the hillside. 'Fascines' (similar to wattles) were placed in the trench so as to wedge the wattles in place, and the trench was topped with a thin layer of soil. Within a couple months the wattles and fascines had sprouted and established near the base of the terrace, and in just a couple years they had grown substantially. The bank has provided effective erosion control since establishment. One feature of using live plants as linear habitats in stream systems is that they confer a sort of 'flexible' resistance - they actually slow the flow of water if appropriately placed. They can also provide good habitat for fish and other wildlife by creating pools and eddies.
The presenter had many effective examples of riparian management such as this one, but this example directly incorporates linear habitats. However, data are not readily available to quantify this type of work.
This example, I should mention, relates to one point Kim mentioned in "Chat Meeting 2." The riparian system runs directly through cropland, which is also under the presenter's management. The newly created linear habitat contributes substantially to on-farm and off-farm benefits. The terrace will be prone to less erosion, and the riparian habitat contributes to wildlife and overall diversity.
This is the website for Mount Jefferson Farms, the company managing theriparian area described here. Click on EPS at left to see a slideshow
illustrating the restoration process. (I find that Mozilla doesn't work with this web page)
http://www.mtjeffersonfarms.com/
Look at this link, and click on "Bioengineering" to read about the process.
http://riparianhabitatrestoration.ca/index.html
That is a really cool example, Danny, and gratifying to see something working so well. Do you think that we'd be able to find very much data on ecosystem services provided by restoration efforts in general? My impression is that many restoration projects eventually report success of vegetation establishment, re-occurrence of exotic invasive spp., etc. but are sketchy in terms of wider service provision, but I could certainly be mistaken on this.
Down the road, what would you think of using some restoration examples as case studies of created linear habitats to build into our framework of LH-natural habitat comparison?