Print PageThe advancement of ecology as a scientific discipline and the application of ecological knowledge to real-world problems depend on the dedication of great ecologists. In this special symposium, we synthesize the life-long achievement of late Professor Joan G. Ehrenfeld. Her distinguished career resulted in major contributions in the areas of invasion biology, wetland ecology, urban ecology, and restoration ecology. A mechanistic understanding of the interactions and feedbacks between exotic invasive plants and soils was championed by Professor Ehrenfeld’s group at Rutgers University. Her emphasis on net impacts of species changes, due to active physiological and legacy feedbacks from above and belowground processes, has advanced ecosystem science greatly in the last two decades.
Results/Conclusions
In particular, research with two invasive understory plants, Berberis thunbergii and Microstegium vimineum, highlighted that plant invasion could cause soil-based ecosystem structure and function to change, including increases in pH and nitrification rates, as well as changes in microbial composition and enzyme activities, and the positive feedbacks that could enhance the spread of invasive plants. Research on Phragmites australis invasion in New Jersey coastal marshes demonstrated how greater demand on nitrogen resources through structural plant differences could alter soil inorganic N availability through microbial processes. In a series of review articles (e.g., Ecosystems 2003: Effects of exotic plant invasions on soil nutrient cycling processes, Annu. Rev. Ecol. Evol. Syst. 2010: Ecosystem consequences of biological invasions), Professor Ehrenfeld synthesized the major advances in the area of invasion biology and species-ecosystem interaction and offered insightful suggestions for future research directions. Professor Ehrenfeld was fundamentally an ecosystem ecologist, focusing on how changes in ecosystem structure altered ecosystem function including complicated interactions and feedbacks, many of which were unseeable yet unavoidable. Her ecosystem approach brought her far beyond invasion biology, and covered broad areas of plant-soil interactions (e.g., in the natural New Jersey Pinelands), degraded urban wetlands, and restoration of woodlands on landfills. Her conclusion that ecosystem processes are often site-specific and context-dependent led her to advocate setting flexible and realistic goals in restoration ecology and conservation decision making. Yet her practicality never diminished her passion for achieving a sustainable earth that supports both human and nature. Biological invasion and other anthropogenic impacts of Homo sapiens remain major challenges to a sustainable earth in the 21st century; Professor Ehrenfeld’s scientific legacy provides critical guidance towards both fundamental scientific research and the policy application of her beloved science of ecology.
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