Research Interests
Ecosystem State Transitions
From desertification in semi-arid grasslands to permafrost melting in the Arctic, ecosystems are changing across the globe at unprecedented rates. It is hard not to read environmental news without uncovering articles on disappearance of coral reefs, the growing threat of invasive species, or the loss of rare habitats. All these occurrences describe the transition of one ecosystem into another. Ecosystem scientists have began to approach these transitions by not only asking, "What is driving this transition?" but also, "What threshold must be crossed for this transition to occur?" By examining critical thresholds, and how they vary across space and time, we can increase our predictive understanding of how and where ecosystem transitions will occur in the future. But perhaps more important, we will be better equipped to intervene and reverse the degradation of the ecosystems that we rely on for biodiversity, climate regulation, and human health and prosperity.
From desertification in semi-arid grasslands to permafrost melting in the Arctic, ecosystems are changing across the globe at unprecedented rates. It is hard not to read environmental news without uncovering articles on disappearance of coral reefs, the growing threat of invasive species, or the loss of rare habitats. All these occurrences describe the transition of one ecosystem into another. Ecosystem scientists have began to approach these transitions by not only asking, "What is driving this transition?" but also, "What threshold must be crossed for this transition to occur?" By examining critical thresholds, and how they vary across space and time, we can increase our predictive understanding of how and where ecosystem transitions will occur in the future. But perhaps more important, we will be better equipped to intervene and reverse the degradation of the ecosystems that we rely on for biodiversity, climate regulation, and human health and prosperity.
Soil Carbon and Nutrient Cycling
Studying plant-soil interactions is important for understanding how soil contributes to human wellbeing (like nutrient retention and carbon sequestration). However, research about carbon and nutrient movement from plants into soils and vice versa has uncovered many surprises that sometimes contradict one another. For example, plants can use carbon that was absorbed years ago to create new roots, and this makes dating roots problematic. In addition, our knowledge of soil ecology is still extremely limited, and so although we understand soil inputs and outputs, we are only partially aware of what organisms drive these processes. Our predictions how soils will respond to anthropogenic climate change are wide-ranging, especially in the context of land use change. Fortunately, technological advances are bolstering our ability to study soil processes and accurately measure and predict soil carbon and nutrient residence time.
Studying plant-soil interactions is important for understanding how soil contributes to human wellbeing (like nutrient retention and carbon sequestration). However, research about carbon and nutrient movement from plants into soils and vice versa has uncovered many surprises that sometimes contradict one another. For example, plants can use carbon that was absorbed years ago to create new roots, and this makes dating roots problematic. In addition, our knowledge of soil ecology is still extremely limited, and so although we understand soil inputs and outputs, we are only partially aware of what organisms drive these processes. Our predictions how soils will respond to anthropogenic climate change are wide-ranging, especially in the context of land use change. Fortunately, technological advances are bolstering our ability to study soil processes and accurately measure and predict soil carbon and nutrient residence time.
Belowground Plant Traits
Belowground plant traits are receiving more attention as acknowledgement of their importance in ecosystem processes increases. Root traits determine the strength and feedback between plants and associated microbial communities. In addition to directly influencing soil nutrient cycling through uptake and exudation, fine roots provide a direct conduit of carbon from the atmosphere to soils. Unfortunately, gathering more data on belowground plant processes is inherently difficult (you can't examine roots without a bit of digging). There is also disagreement about how we should even approach studying roots: how do classify roots in a way that reflects root functioning? What about ecosystem functioning? Currently, two understandings of "root order" exist (a centripetal and a centrifugal classification), and this adds to confusion and miscommunication. To assay root contribution to soil carbon ecosystem residence time, root traits must be considered: the morphological and architectural traits roots develop will affect not only soil properties but also the rate and extent of decomposition. However, root growth is dependent on many environmental and physiological variables that are not yet fully elucidated. Many ecologists have greeted these challenges head on, and studies on root growth and decomposition are now available for many ecosystems and plant types.
Belowground plant traits are receiving more attention as acknowledgement of their importance in ecosystem processes increases. Root traits determine the strength and feedback between plants and associated microbial communities. In addition to directly influencing soil nutrient cycling through uptake and exudation, fine roots provide a direct conduit of carbon from the atmosphere to soils. Unfortunately, gathering more data on belowground plant processes is inherently difficult (you can't examine roots without a bit of digging). There is also disagreement about how we should even approach studying roots: how do classify roots in a way that reflects root functioning? What about ecosystem functioning? Currently, two understandings of "root order" exist (a centripetal and a centrifugal classification), and this adds to confusion and miscommunication. To assay root contribution to soil carbon ecosystem residence time, root traits must be considered: the morphological and architectural traits roots develop will affect not only soil properties but also the rate and extent of decomposition. However, root growth is dependent on many environmental and physiological variables that are not yet fully elucidated. Many ecologists have greeted these challenges head on, and studies on root growth and decomposition are now available for many ecosystems and plant types.
Ecosystem Memory and Legacy Effects
Land use is a vital component of comprehensive studies on ecosystem functioning, particularly for soil nutrient cycling and carbon sequestration. Effects from past disturbances can continue to impact soil processes for decades or even centuries. Anthropogenic activities greatly influence soil through their impacts on plant and soil communities. High-impact agricultural practices such as tillage destabilize soils, but on the other hand, restoration and conservation management promote the growth of plant communities and minimizes human disturbance on the soil. Our ability to predict how ecosystems will respond to extreme events and gradual changes has been severally hampered by our lack of knowledge on legacy. Fortunately, many publicly-available resources exist for finding data on past land use for areas across the world. Certain agencies have developed initiatives designed to capture long-term trends in ecology, such as the National Science Foundations' LTER Network, and these are vital in elucidating legacy effects now and in the future.
Land use is a vital component of comprehensive studies on ecosystem functioning, particularly for soil nutrient cycling and carbon sequestration. Effects from past disturbances can continue to impact soil processes for decades or even centuries. Anthropogenic activities greatly influence soil through their impacts on plant and soil communities. High-impact agricultural practices such as tillage destabilize soils, but on the other hand, restoration and conservation management promote the growth of plant communities and minimizes human disturbance on the soil. Our ability to predict how ecosystems will respond to extreme events and gradual changes has been severally hampered by our lack of knowledge on legacy. Fortunately, many publicly-available resources exist for finding data on past land use for areas across the world. Certain agencies have developed initiatives designed to capture long-term trends in ecology, such as the National Science Foundations' LTER Network, and these are vital in elucidating legacy effects now and in the future.