The two basins of this seepage lake were separated by a vinyl curtain in August 1984 after a year of background studies, and acidification of one basin with H2SO4 began at ice-out in 1985. Chemical and biological responses measured during successive 2-yr periods at pH ~5.6, 5.1, and 4.7 verified some but not all impacts predicted at the outset. Changes in major, minor, and trace ions generally agreed with predictions. Internal alkalinity generation (IAG) increased at lower pH, and sulfate reduction eliminated ~50% of added H2SO4. Sediment cation exchange was important in IAG and acidified surface sediments, possibly diminishing the lake's ability to counteract further H+ inputs. Mass loss of oak leaves was reduced at pH 5.1 (birch leaves at pH 4.7). Population parameters were more sensitive than community measures for plankton. Species composition changed at each pH, especially at pH 4.7. Many changes in zoopiankton and benthos were indirect responses to an algal mat that developed at lower pH or to food web interactions; these were not predicted accurately. Sensitivity of major fishes to lower pH was Ambloplites rupestris > Micropterus salmoides > Pomoxis nigromaculatus > Perca flavescens. Fish production was reduced at pH's above those resulting in population decreases.

Carbonate-sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface-water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater-fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air-water temperature relationships for 40 GWFS in southeastern Minnesota. A 40-stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R 2 of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface-water dominated streams. Regression models for streams with high R 2 values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater-fed systems, but will do so at a slower rate than surface-water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.(KEY TERMS: karst hydrology; surface water/groundwater interactions; linear regression models; climate change/variability; rivers/streams; land management.)

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Climate change is a certainty, but the degree and rate of change, as well as impacts of those changes are highly site-specific. Natural World Heritage sites represent a treasure to be managed and sustained for all humankind. Each World Heritage site is so designated on the basis of one or more Outstanding Universal Values. Because climate change impacts are site-specific, adaptation to sustain Universal Values also must be specific. As such, climate change adaptation is a wicked problem, with no clear action strategies available. Further, adaptation resources are limited at every site. Each site management team must decide which adaptations are appropriate investments. A triage approach guides that evaluation. Some impacts will be so large and/or uncertain that the highest probability of adaptation success comes from a series of uncertain actions that reduce investment risk. Others will be small, certain, comfortable and yet have low probable impact on the Universal Value. A triage approach guides the management team toward highest probable return on investment, involving stakeholders from the surrounding landscape, advancing engagement and communication, and increasing transparency and accountability.

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Protected areas, such as natural World Heritage sites, RAMSAR wetlands and Biosphere Reserves, are ecosystems within landscapes. Each site meets certain criteria that allow it to qualify as a heritage or protected area. Both climate change and human influence (e.g., incursion, increased tourist visitation) are altering biophysical conditions at many such sites. As a result, conditions at many sites are falling outside the criteria for their original designation. The alternatives are to change the criteria, remove protection from the site, change site boundaries such that the larger or smaller landscape meets the criteria, or manage the existing landscape in some way that reduces the threat. This paper argues for adaptive heritage, an approach that explicitly recognizes changing conditions and societal value. We discuss the need to view heritage areas as parts of a larger landscape, and to take an adaptive approach to the management of that landscape. We offer five themes of adaptive heritage: (1) treat sites as living heritage, (2) employ innovative governance, (3) embrace transparency and accountability, (4) invest in monitoring and evaluation, and (5) manage adaptively. We offer the Australian Wet Tropics as an example where aspects of adaptive heritage currently are practiced, highlighting the tools being used. This paper offers guidance supporting decisions about natural heritage in the face of climate change and non-climatic pressures. Rather than delisting or lowering standards, we argue for adaptive approaches.

American ecologists recently began to address the ecology of cities. Concurrently, higher education institutions have developed sustainability education programs and instituted sustainability policies and projects. This paper draws together these two disparate areas by examining the nitrogen (N) budget of the Twin Cities campus of the University of Minnesota. We addressed the question: what were the annual inputs, outputs and internal cycles of N on the University of Minnesota Twin Cities campus? We found that 508 Mg N yr-1 were brought into the campus and 494 Mg N yr-1 were emitted from the University of Minnesota campus. The largest N inputs were abiotic fixation (conversion of N 2 to NO x by combustion) and food for humans and animals. The largest N output was NO x , followed by wastewater. Our results expand the understanding of the ecology of institutions within an urban area and provide an opportunity for improving urban ecology education and environmental policy at educational institutions.