Tuesday, March 9, 2010

Landscape approaches for the study of aquatic ecosystems


Well, I'm trying to read a paper a day (this can be really hard with 2 kids and a job that doesn't encourage it), and today I randomly pulled up this paper: Johnson and Host "Recent developments in landscape approaches for the study of aquatic ecosystems" (full cite below).

Let's just say that there's a lot here.

Basically, this paper is part of a big-time retrospective done by J-NABS in celebration of their25th anniversary (they are all open source, so by all means download away). I'm a big fan of NABS, and I love the journal. Virtually every article in this special issue holds some real interest to me. This Johnson and Host paper might be among the most relevant, because I am currently working on a Catchment Stoichiometry special issue for Freshwater Bio (whether or not it is successful or not is unfortunately still up in the air).

Regardless, this paper has a ton of great information. Essentially, the authors are reviewing the landscape approaches used in aquatic ecology and updating some of the more recent reviews on terrestrial aquatic linkages (with a particular emphasis on J-NABS contributions).

There's so much here that I don't really know how to summarize it for easy digestion. The authors really focus in on watershed scale studies (i.e., how do watershed properties affect the aquatic properties), and of course those kinds of studies have exploded in the last 15-20 years as both recognition of this level of biological organization has expanded and the tools available to do the research have become widely available. Aerial photography, combined with fairly sophisticated computer software (i.e., ESRI's ArcGIS software) have become available to many, many researchers. As a result, many many phenomena have been investigated with varying levels of success (e.g., species distributions and diversity, water chemistry, water velocity and temperature, habitat distribution, etc.).

Unfortunately, there are still some real challenges. Practically speaking, not a lot of people are speaking the same language in this field yet. Even within this paper, I was occasionally confused by changing terms, or at least terms that seemed to be very similar (catchment vs. watershed is explained; habitat versus reach I must have missed). More theoretically, there is a lot of difficulty in trying to figure out the most appropriate scale for investigating some phenomena, and sometimes as a result, the mechanistic connections between observed relationships is not always clear (in some cases it is just plain confusing).

Most or many of the landscape studies done on aquatic ecosystems are attempting to determine the extent or effects of various anthropogenic stressors. However, the authors point out that anthropogenic disturbance itself is definitely confounding our ability to distinguish what is happening. Some impacts may have lag times, others may so homogenize the landscape that important relationship cannot be seen. The authors also stress that future research will need to integrate landscape/catchment level data with local data (i.e., point source samples) better, because an abundance of local data is becoming available. Being able to manage and analyze these huge, integrated datasets seems like a formidable problem (perhaps one that Morpho can assist with?).

Maybe the biggest take-home message on the future of landscape studies of aquatic ecosystems is summarized here:

We need: 1) robust statistical and sampling techniques to discrim- inate among multiple stressors (e.g., climate and land use) and among anthropogenic and natural stressors, 2) mechanistic and empirical models linked to multi- sensor systems, 3) cross-sensor integration to expand the temporal and spatial density of data collection, and, 4) sustained communication between researchers and managers to ensure rapid deployment of mitigation and adaptation strategies.

Seems pretty simple, but very difficult.


Overall a great paper that provides a wealth of information on how and what has been done with regards to landscape studies in aquatic ecosystems. I would deem this paper essential for anyone doing work on aquatic-terrestrial linkages.

Johnson, L.B. and G.E. Host (2010). Recent developments in landscape approaches for the study of aquatic ecosystems Journal of the North American Benthological Society, 29 (1), 41-66 : 10.1899/09-030.1

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