Document Type

Honors Thesis

Major

Ecology & Environmental Sciences

Advisor(s)

Rachel Schattman

Committee Members

Jason Lilley, Philip Fanning, Margaret Killinger

Graduation Year

May 2024

Publication Date

Spring 5-2024

Abstract

Conservation agriculture approaches are gaining traction as the planet’s food system grapples with climate change, oil depletion, and rampant environmental degradation (Palm et al., 2014). Cover cropping is an integral practice of conservation agriculture. Ground dwelling arthropods play an important role in agroecosystems, providing ecosystem services including seed predation and nutrient cycling. Because the relationship between cover crops and arthropod abundance are likely influenced by management conditions, I investigated arthropod abundance in a field interseeded with cover crops on a research farm in Maine, United States. Interseeding is an emerging practice in the northeastern United States, with potential to address the barriers to more typical cover cropping. Such barriers are primarily economic and ecological in nature. For example, it can be difficult to achieve sufficient biomass when cover crops are planted late in the growing season, diminishing potential ecosystem service benefits. The influence of interseeded cover crops on beneficial arthropods has not been researched in this bioregion.

In this study, arthropods were sampled using pitfall traps three times during the 2023 fall growing season. I sampled from plots that were either cover-cropped or not cover-cropped (the latter being the control treatment), with 4 replicates per treatment. Harpalus rufipes DeGeer (Coleoptera: Carabidae) was the most abundant groups sampled, with members of the Gryllus genus (Orthoptera: Gryllidae) also highly abundant. H. rufipes and G. species are granivorous, providing seed predation services to regulate weed seedbanks. No significant difference in abundance or diversity was found between treatments, though other conditions observed in the experiment likely influenced this outcome. A moderate positive linear relationship was found between canopy cover, which included both cover crops and weeds, and arthropod abundance. Both cover crops and weeds provide habitat for beneficial arthropods. Suitable habitat was less available when intercrop space was left bare. These findings show that cover crops provide the valuable habitat for beneficial arthropods, without the management complications and yield losses associated with high weed pressure. The findings prompt further research on the myriad factors influencing beneficial arthropod abundance in agroecological systems.

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