Integrating transport processes into ecological research: Moving beyond spatial stasis

Background/Question/Methods

Although earth system sciences have a long history of quantifying horizontal movement of materials across landscapes and regions, terrestrial ecological research has only recently begun to quantify its impact on ecosystems. Increasing evidence suggests that ecological processes, from physiological to biogeochemical, can be strongly affected by transport processes that redistribute organisms, organic material, soil, and nutrients.  The importance of these transport processes appears particularly strong in dryland ecosystems, where low and discontinuous canopy cover combine with extreme events (e.g., convective windstorms and thunderstorms) to enable movement of materials.  Failure to account for the movement of materials through space may lead to an incomplete – or incorrect – understanding of ecosystem behavior.  Ecologists are challenged, however, to develop appropriate methods for adequately and dynamically incorporating material transport into process-oriented research projects.  We provide an overview of the recent research exploring how ecological processes are influenced by material movement and assess how relaxing assumptions of spatial stasis have altered our interpretation of and perspectives on ecological processes.  New methods and techniques to describe transport processes in an ecological context will also be covered.

Results/Conclusions

Recent work suggests that rates of aeolian and fluvial material transport differ among dryland regions of the world, with flux rates being strongly influenced by vegetation structure.  Ecological processes affected by material transport include seed dispersal, seedling establishment, plant stress and growth, species interactions, and rates of decomposition.  These direct effects are augmented by indirect effects on nutrient availability and edaphic heterogeneity. Furthermore, animal habitats, microbial transport, and human health may be impacted by transport processes at scales ranging from local, to regional, to global.  The talks in this session will provide examples of how transport processes have been addressed in descriptive, experimental and modeling studies of ecosystems.  We present a framework for projecting the systems and processes most likely to be affected by material transport processes and for anticipating where human activities (e.g., disturbances, land cover change) might most strongly affect ecological processes via influences on material transport.  Finally, we suggest areas for future research collaborations between ecologists and earth system sciences.