Carbon, Critters, and Cattle: Dr. Nevo Sagi, a Vaadia-BARD Postdoctoral fellow at the University of Texas in Dr. Amanda Koltz’s lab, shares his journey into soil ecology
What is the main focus of your postdoc work?
“My postdoc research focuses on the role of soil macro-invertebrates in mediating the effects of livestock on soil carbon across different environmental conditions.
Existing research suggests that livestock can have either positive or negative effects on soil health depending on stocking regimes and local climate. Macro-detritivores are invertebrate animals – such as dung beetles, termites and woodlice – that feed on dead organic matter. These critters play an important role in recycling plant material and livestock feces, especially in arid regions. However, their influence on soil carbon fluxes, and how it is shaped by different grazing regimes remains unclear.
In my postdoc, I characterize macro-detritivore ecological communities and quantify their contribution to removal of cattle dung and plant residues along a broad aridity gradient under three grazing regimes (rotational, continuous, and no grazing) at multiple sites across Texas. In addition, I conduct a controlled mesocosm experiment (experimenting in Ecosystem, in a controlled yet relatively natural environment) to gain a mechanistic understanding of the interactions between livestock and macro-detritivore fauna and their combined effect on soil carbon inputs.
The overall goal of the project is to distill fundamental understanding of how soil fauna regulates carbon dynamics in grazed drylands, providing a scientific basis for using these organisms as indicators and enhancers of soil health and pasture productivity.”
What got you interested in your area of research?
“I try to understand how ecosystems function from a broad perspective that considers both biotic and abiotic factors and their interactions.
Specifically, I am interested in how animals affect ecosystem processes such as elemental cycling. Large herbivores (plant-eating animals) and macro-detritivores consume substantial amounts of plant material and act as ecosystem engineers by significantly altering their physical environment. Their combined trophic and non-trophic effects make them central to understanding animal impacts on ecosystems.
In my previous research, I found that macro-detritivores play an exceptionally important role in carbon and nutrient cycling in warm deserts compared to cooler, wetter environments. The outsized influence of livestock, which are present in much greater numbers than wild herbivores, on the global carbon cycle led me to explore how interactions between livestock and macro-detritivores unfold.
Preliminary data from a pilot experiment I conducted in Israel suggest that the effects of cattle grazing on plant diversity cascade to influence the role of macro-detritivores in plant litter removal. This kind of complex, multi-trophic ecological interaction sparks my curiosity with the promise of exciting and influential discoveries ahead.”
What are your plans after your postdoctoral research?
“I plan to come back to Israel and position myself where I can do the most exciting and impactful (agro)ecological research.”
What tip would you give someone beginning their postdoctoral research?
“Living and doing research in a new country brings new challenges both in research and in life. Take good care of your family (if you have one) and make sure you enjoy what you do.”
