McCulley, Rebecca L

McCulley Lab Introduction

The McCulley Lab explores the ecological factors and processes that influence rates of biogeochemical cycling and ecosystem structure and function in grasslands and agroecosystems at both local and regional spatial scales and across seasonal, yearly, and decadal timescales. Some of our dominant research questions include:

• How do grasslands respond to climate change, eutrophication, and land-use change?
• What are the ecosystem consequences of fungal symbioses in grasses?
• What controls litter decomposition in aridlands?
• How do invasive species affect grassland structure and function?
• How do changes in land management or livestock management impact agroecosystem function and resilience?

Our research program is field-based, but we also employ stable isotope and cellular and genomic-level techniques when appropriate, as well as occasionally perform controlled environment work. We frequently work across atmosphere-plant-microbe-soil boundaries, looking at the interaction of these various ecosystem components. Because a number of biogeochemical processes are controlled by microbes, our work frequently generates large DNA-based microbial datasets that require advanced computing resources to analyze. We are interested in how microbial communities are altered by factors such as climate change, land use management, grazing livestock management, ultraviolet radiation, and invasive species abundance. We try to link changes in microbial communities to changes in other measured ecosystem functions, such as litter decomposition, greenhouse gas emissions, and nitrogen cycling. The goal of our research is to help humans better understand and predict the environmental consequences of our collective actions.

Biochanin A livestock feed supplementation in sheep: soil trace gas emissions and soil microbial community consequences.

Livestock grazing alters plant communities, nutrient cycling, soil biological communites, carbon storage, and trace gases important in climate change. One strategy shown to increase livestock gains for meat production is dietary supplementation of ruminant animals with biochanin A, an isoflavone present as a secondary metabolite in the common pasture legume, red clover (Trifolium pratense). Biochanin A alters the abundance of some bacteria species in the livestock rumen and results in greater protein digestion and more efficient livestock weight gains. This study aims to investigate whether biochanin A or its breakdown products, genestein and p-ethylphenol, alter the soil bacterial and fungal communities when livestock waste from sheep fed biochanin A is applied to soil. We hypothesize that biochanin A feed supplementation in sheep affects trace gas emissions from soil and that metabolites from livestock waste also change soil biological communities. We are particularly interested in how the bacterial to fungal ratios in soil change over time.

Personnel:

Rebecca L McCulley, PI

Alayna Jacobs: PhD Candidate, UK Added 06/25/2021

Audrey Law, PhD, UK, Added 11/11/2020

Computational Methods:

We will be processing Illumina Miseq generated sequences and analyzing sequence data fastq.gz files thorough the Mothur pipeline, following the SOP on https://mothur.org/wiki/miseq_sop/ .

Software:

We will use Mothur and Python.

UK and non-UK Collaborators:

Michael Flythe, PhD, USDA-ARS

Jessica Ferrell, USDA-ARS

Don Ely, PhD, UK

Grants:

Publications: