Research

Assessing ecosystem risk and vulnerability to change

Ecosystems must be comprehensively defined and characterized in order to accurately assess their resilience to global change and determine conservation priorities. Pond ecosystems are hotspots of biodiversity and carbon cycling, globally abundant, and subsidize terrestrial food webs. However, we have lacked both a standard definition of a pond and an understanding of their relative importance in a landscape context. 

Relevant work:

• What is a pond? A functional definition to distinguish ponds from lakes and wetlands

• What is a Sierra pond? Snowfall and pond volume drive summer mountain pond dynamics in California’s Sierra Nevada (in review)

Like ponds, lakes reflect processes within their surrounding catchments and the waters that feed into them. As a result, lakes can act as key sentinels of wider landscape-level changes, making them an ideal study system to quantify climate change impacts.

 Relevant work:

• Using knowledge-guided machine learning to assess patterns of areal change in waterbodies across the contiguous U.S. 

Linking global change to ecological mechanism

Wildfire smoke threatens lakes, as it can reflect or scatter sunlight and deposit ash within ecosystems, altering several key physical, chemical, and biological lake processes. We have characterized the effects of wildfire smoke on lakes on several scales, from defining the global scope of impact to investigating mechanisms of change in single ecosystems. 

Relevant work:

• Wildfire smoke affects lake ecosystems (Dissertation chapter)

• Wildfire smoke reduces lake ecosystem metabolic rates unequally across a trophic gradient 

• Wildfire smoke reduces water temperature and metabolic rates in lakes and ponds across a watershed  (Dissertation chapter; in revision at L&O Letters)

Predicting and modeling biological outcomes

A mechanistic understanding of ecosystem drivers and features that determine community assembly and diversity is required to understand conservation priorities and potential outcomes in systems and species at risk. To address this, we have investigated abiotic drivers of change in multiple freshwater communities experiencing the effects of drought, human modification, and warming. 

Relevant work:

• Evidence of a shift in the littoral fish community of the Sacramento-San Joaquin Delta 

• Wetland geomorphology and tidal hydrodynamics drive fine-scale fish community composition and abundance

• Effects of warming on mountain lake zooplankton community dynamics (Dissertation chapter; in prep)