Land-water interactions in North Temperate Landscapes

Contacts

Monica Turner, Ishi Buffam

Keywords

riparian, watershed, shoreline development, terrestrial-aquatic interactions, LTER, eutrophication, land-use change

Research Overview

Lakes and rivers are important features of the landscape of northern and southern Wisconsin. In collaboration with faculty and students at the Center for Limnology, our lab has focused on the landscape setting surrounding fresh water ecosystems and on the interactions between the terrestrial and aquatic ecosystems. In addition, our research contributes to understanding linked social-ecological systems. We currently are involved in three ongoing projects:

• Comparative Study of a Suite of Lakes in Wisconsin (North Temperate Lakes LTER site)
• Hydrologic and biogeochemical fluxes in regional land-water mosaics
• Eutrophication thresholds – assessment, mitigation and resilience in landscapes and lakes

Comparative Study of a Suite of Lakes in Wisconsin (North Temperate Lakes LTER site)

The North Temperate Lakes Long-Term Ecological Research (NTL-LTER) program seeks to understand the long-term ecology of lakes and their interactions with a range of important landscape, atmospheric, and human processes.  Freshwater lakes are a nexus of ecological, economic and social processes on many landscapes throughout the world.   Small, inland lakes are particularly prominent throughout the Upper Great Lakes region of North America.  Thousands of inland lakes play a central role in regional hydrologic and biogeochemical cycles, in biological processes influencing the area's diversity of aquatic and terrestrial life, and in a wide range of human activities. Over the past two centuries, deforestation, fire suppression, agriculture, industrialization, and urbanization have transformed landscapes within the region and fundamentally altered the interactions between lakes and their surroundings.  For the next century and beyond, the quality of life and the economies of the region will depend upon the quality of the lakes. The overarching question of NTL-LTER is:  How do biophysical setting, climate, and changing land use and cover interact to shape lake dynamics and organization in the past, present and future?

Most recently, our lab has been involved in research focused on understanding the changes in land use and land cover in the riparian zones surrounding lakes of the Northern Highlands Lake District (NHLD) in the forested landscape of Vilas County, as well as the Yahara chain of lakes in the agricultural-urban landscape surrounding Madison.  Read more about riparian land-use change…

Funding source:

National Science Foundation

Selected publications:

Gergel, S. E., M. G. Turner, and T. K. Kratz.  1999.  Scale-dependent landscape effects on north temperate lakes and rivers.  Ecological Applications 9:1377-1390.

Riera, J., P. R. Voss, S. R. Carpenter, T. K. Kratz, T. M. Lillesand, J. A. Schnaiberg, M. G. Turner, and M. W. Wegener.  2001.  Nature, society and history in two contrasting landscapes in Wisconsin, USA:  interactions between lakes and humans during the 20th century. Land Use Policy 18:41-51.

Schnaiberg, J., J. Riera, M. G. Turner and P. R.Voss.  2002.  Explaining human settlement patterns in a recreational lake district: Vilas County, Wisconsin, USA. Environmental Management 30:24-34.

Turner, M. G., S. Collins, A. Lugo, J. Magnuson, S. Rupp and F. Swanson.  2003. Long-term ecological research on disturbance and ecological response. BioScience 53:46-56.

Turner, M. G. and S.  R.  Carpenter.  2005. Challenges for riparian science.  Page 16 In:  Naiman, R.J., H. Decamps, and M.C. McClain.  Riparia. Academic Press, San Diego.

Hydrologic and biogeochemical fluxes in regional land-water mosaics

Our overarching goal is to understand carbon and nutrient cycles for a landscape on which terrestrial and freshwater systems are intimately connected in multiple and reciprocal ways.  In the Northern Highlands region of Wisconsin, we are studying a spatially complex landscape in which the dominant land covers are diverse types of forests and shrublands (81% of land surface) and lakes (13%).  We hypothesize that reciprocal interactions of terrestrial vegetation and lakes, through flows of water, organic carbon, and nutrients, are more complex than previously thought.  Improved understanding of these interactions demands a combination of terrestrial and aquatic expertise, in an appropriately integrated research plan. 

Terrestrial ecologists have made great strides in understanding the geophysical template, climate, disturbance regimes, and vegetation dynamics that control groundwater, surface water, carbon and nutrient fluxes in the Northern Highlands and other landscapes.  Despite these advances, there are considerable gaps in understanding the magnitude and spatial patterns of biogeochemical fluxes.  For example, terrestrial ecologists have found important imbalances in the carbon cycle.  These gaps may be closed by studies that consider the complete landscape – that is, the integrated behavior of terrestrial vegetation and surface waters. The goal of our project is to understand how the extent of surface water and wetlands affects ecosystem production, respiration, and spatial flow of organic carbon on complex, heterogeneous landscapes.  The approach centers on development of a new integrated spatial simulation model for hydrology and biogeochemistry of the Northern Highland Lake District (NHLD) of northern Wisconsin and Upper Michigan, a complex landscape of with over 7500 lakes and diverse terrestrial ecosystems. This project is ongoing.  Read more for a summary of our research results …

Funding source:

Andrew W. Mellon Foundation

Selected publications:

Cardille, J. A., Coe, M. T., and J. A. Vano. 2004. Impacts of climate variation and catchment area on water balance and lake hydrologic type in groundwater-dominated systems: a generic lake model. Earth Interactions 8(13): 1-24.

Turner, M. G. and J. A. Cardille. 2007. Spatial heterogeneity and ecosystem processes. Pages 62-77 in: J. Wu and R. J. Hobbs, editors. Key topics in landscape ecology. Cambridge University Press.

Vano, J.A., Foley, J.A., Kucharik, C.J., and M.T. Coe, Evaluating the seasonal and interannual variations in water balance in northern Wisconsin, USA, using a land surface model.  J. Geophys. Res., 111, G02025, doi:10.1029/2005JG000112.

Eutrophication thresholds – assessment, mitigation and resilience in landscapes and lakes

In collaboration with Steve Carpenter and Jon Foley, we are beginning a new project that will address thresholds in eutrophication for lakes in the Yahara chain.  Eutrophication, a persistent environmental problem characterized by turbid water, toxic algae, fish kills, waterborne disease, and loss of aquatic ecosystem services, may be related to important thresholds in the phosphorus (P) cycle. We will address two main questions: (1) What thresholds in the transport and recycling of P in linked terrestrial-aquatic ecosystems cause lakes to switch between clear-water and eutrophic states? (2) How can thresholds for transport and recycling of P be manipulated to mitigate eutrophication, or increase resilience of clear water lakes against eutrophication? The research will conduct a retrospective analysis of the Yahara watershed and its major lakes (near Madison, Wisconsin), using a substantial historical data base of land characteristics and limnology. Changes in this watershed-lake system are emblematic of those in many agricultural, urbanizing regions of the United States. Approaches include statistical analyses of three different types of lake models and simulation studies using a Terrestrial-Aquatic P model. The project will describe thresholds related to eutrophication with respect to landscape, biogeochemical, and statistical characteristics. We will (1) establish whether the thresholds are likely to produce important changes in eutrophication, (2) determine how key controlling variables such as climate, landscape characteristics, land use/cover change, agricultural practices, and management actions affect thresholds, (3) evaluate prospects for mitigating eutrophication through interventions that utilize thresholds, and (4) assess changes in controlling variables that would increase or decrease resilience of clear-water and eutrophic regimes. Better understanding of thresholds related to eutrophication is a prerequisite for correcting this persistent problem in order to improve ecosystem condition, human health, and livelihoods. Read research proposal (PDF)....

Funding source:

STAR Program, US Environmental Protection Agency