Dominant plant species with high abundance and biomass are major contributors to nutrient and energy pools in many ecosystems. Therefore, the loss of dominant plant species can result in a reduction of ecosystem function, particularly if the remaining species in the community do not have similar functional roles. Many efforts have been made to document the effect of dominant species loss. These include observational data from communities where the dominant species has declined, comparative studies of mono- vs.

This Working Group session is offered by the newly NSF-funded LTER Math-Science-Partnership (MSP) Pathways to Environmental Literacy project. Presentations by panelists at this session address topics at the intersection of science teaching and learning and the myriad issues of citizenship, equity, diversity, and place. The focus areas of the Pathways project are: Biodiversity, the Water Cycle, and the Carbon Cycle.

 Most climate change research has concentrated on the direct effects of environmental change for individual species and their interactions. By affecting key foundation species and ecosystem engineers, however, climate change may have a variety of indirect that may complicate our abilities to predict the response of communities and ecosystems. In California, climate change has increased the frequency and intensity of storms over the last half century.  Storms may directly alter the structure of kelp forest food webs via disturbance.

Stream microbial mats are dynamic communities of phototrophic and heterotrophic organisms that develop over intra-seasonal and inter-seasonal time scales. Diatom community composition is influenced by successional processes and physical and chemical gradients that together act to shape stream benthic habitats. In ephemeral streams of the McMurdo Dry Valleys (Antarctica, MCM LTER), previous work has demonstrated that in streams across the Fryxell Lake Basin, the diatom composition in microbial mat communities is determined largely by the annual and historical flow regime.

 Tropical reef ecosystems lie at the interface of productive, populated terrestrial coastlines and unproductive, oligotrophic oceanic waters. Corals and other dominant reef organisms maintain complex symbiotic interactions with both surficial and planktonic aquatic microbial communities, but the processes defining the composition and life history of these communities are poorly understood.

Species differences in germination play a crucial role in structuring annual plant communities. Germination depends upon numerous cues, including temperature and moisture, with global climate change models predicting increasing nighttime temperatures and more variable precipitation with larger, but less frequent rainstorms.

Ecological communities can undergo sudden and dramatic changes between alternative states. Understanding the mechanisms that trigger such shifts and those that maintain them is crucial for ecological prediction as well as natural resource management. Differentiating between potential mechanisms is difficult however, because shifts are often recognized only in hindsight, and many occur on such large spatial scales that field experiments to test their cause are not possible.

Two of the most pervasive human impacts on ecosystems are alteration of global nutrient budgets and changes in the abundance and identity of consumers. Fossil fuel combustion has doubled and agricultural fertilization has quintupled global pools of nitrogen and phosphorus relative to pre-industrial levels. Concurrently, habitat loss and degradation and selective hunting and fishing have disproportionately removed consumers from food webs.

The aim of this working group will be to discuss the upcoming Antarctic Field Season. By holding this meeting at the ASM we will take advantage of the fact that a large group of PAL and MCM investigators, staff, and students will be present and available to attend, although the meeting will be open to all.