June HydroClim Minnesota

The June edition of HydroClim Minnesota is available on-line. Surprising how much of the state is already in abnormally dry conditions. /dps

One hundred questions...

The journal Conservation Biology has an early on-line release of a fascinating multi-author essay entitled "One Hundred Questions of Importance to the Conservation of Global Biological Diversity". The essay is based on an extensive dialogue and survey process and it groups the questions identified into twelve sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. I have posted a two-page, pared down Adobe pdf version of just the questions (which I originally developed as a hand-out for next week's final session of my Conservation Biology course).

The questions presented provide an interesting look over the horizon and suggest emerging issues and concerns. Because the five questions related to Freshwater Ecosystems (#54-58) are of particular interest to me, I list them in full below:

• How can freshwater biodiversity and ecosystem service values best be incorporated in the design of water-provisioning schemes for direct human use and food production?
• Which aquatic species and communities are most vulnerable to human impacts, and how would their degradation affect the provision of ecosystem services?
• Where will the impacts of global climate change on hydrology be most extreme, and how might they affect freshwater species and the ability of wetlands and inland waters to deliver ecosystem services?
• Which multinational governance, cross-sector cooperation arrangements, and finance mechanisms will make freshwater ecosystem management more effective and reduce international conflicts over water?
• How does investment in restoration of wetlands and riparian areas compare with construction of dams and flood defenses in providing cost-effective improvements in flood management and the storage and retention of water for domestic, industrial, and
  agricultural use?

The third question, related to climate change impacts on freshwater systems, is particularly relevant to those of use living in mid-continent, mid-latitude locations, a fact underscored by a feature article in today's Strib on water quality in west-metro lakes. Reduced rainfall last summer appeared to limit external nutrient loading thus resulting in clearer water. In contrast, and more locally, our data from Grace Lake suggest that longer hotter summers, which result in extended periods of stratification and consequent increased internal loading, will result in dramatic increases in mid-summer algal growth with corresponding shifts in fish communities and overall aesthetic appeal. In any case, a changing climate will fundamentally reshape the dynamics of ecological processes in our lakes and rivers (in ways we are only beginning to understand).

Note: The fifth freshwater question is also especially relevant regionally given the extent of northern Minnesota wetlands and the on-going flood related issues in the Red River Valley.

HydroClim Minnesota April 2009

The April edition of HydroClim Minnesota is now available. While March was very wet in much of northern Minnesota, it was quite dry in other parts of the state (a few of which are in Moderate Drought status). There is also some interesting material concerning the Red River Valley flooding that is worth a look. Enjoy!

Ice out progress 2009

Last spring I made a short post here linking to daily satellite imagery useful for monitoring ice-out progress. This University of Wisconisn based site has now been moved to http://ge.ssec.wisc.edu/modis-today/ and I have learned a bit more about how to get maximum utility out of the images. When you get to the site, first click anywhere within the boundary Minnesota which will open the USA3 image for the day. Next choose the '250m' scale to zoom in. Now for the cool part...select the 'false color' option and any open water will be immediately obvious! As another hint to anyone following ice-out progress on the Rainy River, toggle off the 'State borders' so as to not mask image data. Enjoy!

Urban metabolism and the pace of rural life

In the course of looking for something else, I came across a fascinating paper on "urban metabolism" (see pdf of Bettencourt, L. and others. 2007. Growth, innovation, scaling, and the pace of life in cities. Proc. Natl. Acad. Sci. USA 104(17): 7301-7306 ). Among many other interesting things, this article shows that mean walking speed increases as function of population (see top figure). For those not familiar with natural logarithmic scales, what the figure shows is that in a city of around 3000 people (~e⁸), average walking speed is about 1 meter per second (e⁰) . In a village of 400, average walker velocity slows to roughly 0.8 meters per second while in a city of 1.2 million the typical pedestrian is hustling along at 1.5 meters per second.

Two things are remarkable about this finding. First, and as is shown in the lower figure, metabolic rates of individual organisms typically decrease as body size increases. Somehow, cities as organic entities function in a way that is fundamentally different than what we see in individual animals. Second, the incredibly tight scaling of walking speed to city size is extraordinary. That such a basic human behavior is so closely tied to population density has profound implications for the way we perceive the world.

As I have worked with lakshore property owners from around Minnesota over the past couple years I have often been struck by the starkly contrasting perspectives of urban and rural residents. Perhaps this work offers a hint at why what we value here in northern Minnesota is so different than what is valued by residents of the Twin Cities metropolitan area. If population density can influence our mean walking speed is it any wonder that it might also influence more subtle attitudes and behaviors?

'...what that must do to their souls, how different they must be in their private concerns and evaluations and wishes.' -- Dean Moriarty, in Kerouac's 'On The Road'

Motorized Watercraft Effects in Aquatic Ecosystems

As the intensity of boat traffic and typical horsepowers increase with demographically-driven(re-)development of lakeshore, we have reason to be concerned about adverse impacts of boat motors on aquatic ecology. Asplund (2000) provides an excellent and understandable 21-page review of relevant studies. Unfortunately, the trends revealed are more than a little disconcerting. Asplund's review deserves wide circulation among lake associations and others concerned with maintaining ecological integrity of our lakes and streams.

As the preceding fihure shows, adverse impacts are not limited to very shallow areas. A 100 HP motor can stir-up phosphorus-laden bottom sediments down to water depths of 18 feet! When the paper this figure is derived from was published in 1991, a 100 HP motor was near at the upper end -- now motors in excess of 200 HP are relatively common even on small lakes.

Prop wash can greatly increase turbidity, re-suspend algae stimulating phosphorus, and disturb critical spawning and nursery habitat for fish and other aquatic animals. Perhaps most critically, prop wash can destroy plant communities effectively "plowing" lake bottoms and opening sediments to invasive species such as Eurasion watermilfoil (EWM).

Want to reduce the likelihood and adverse impacts of EWM on your lake? Consider comprehensive educational campaigns or local ordinances to reduce damage to native plant communities caused by careless (though seldom malicious) powerboaters. That will, of course, be a very tall order since old habits die hard.

One excellent place to start would be to provide signage at accesses discouraging the now almost ubiquitous practice of power-loading (i.e., driving your boat on to the trailer) . Power-loading produces a pronounced scour hole and wide spread sedimentation at just the place where invasive species are most likely to enter a lake. In effect, power-loading is equivalent to putting out a welcome mat for Eurasion watermilfoil and other invasive plants. With spring just around the corner, it is time to think about such things...

March HydroClim Minnesota

The March edition of HydroClim Minnesota has been posted. This past meteorological winter was 3-6 degrees F below the long term average and was the coldest since 2000-2001. Major flooding of the Fargo-Moorhead area appears to be a near certainty. Have a look!