Graduation Date

Spring 2026

Document Type

Thesis

Program

Master of Science degree with a major in Biology

Committee Chair Name

Dr. Catalina Cuellar-Gempeler

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

Dr. Paul Bourdeau

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Dr. Jianmin Zhong

Third Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Fourth Committee Member Name

Dr. Leonora Bittleston

Fourth Committee Member Affiliation

Community Member or Outside Professional

Keywords

Biodiversity–ecosystem functioning, Metacommunity ecology, Microbial communities, Darlingtonia californica, California pitcher plant, Aquatic microecosystems, Ecosystem function, Community succession, Spatial structure, Environmental filtering

Subject Categories

Biology

Abstract

The relationship between biodiversity and ecosystem-function (BEF) has been a central focus of ecological research for the last three decades, yet the role of space in shaping BEF relationships remains relatively unknown. Research has shown that community diversity and composition can strongly influence productivity, nutrient cycling, and decomposition, but much of this work treats communities as spatially isolated, leaving open how dispersal and other spatial processes shape BEF at broader scales. To begin addressing this gap, I used microbial communities inhabiting Darlingtonia californica pitcher plant leaves to evaluate how spatial organization and successional change shape biodiversity and ecosystem-functioning. I quantified bacterial biodiversity using 16S rRNA amplicon sequencing and evaluated ecosystem-functioning by measuring prey degradation, carbon substrate use, and fluid protein concentration across 54 pitcher leaves in Gasquet, California. Results indicated little evidence for metacommunity-scale spatial clustering of diversity or ecosystem-functioning at the scale sampled. Instead, the strongest and most consistent predictor of biodiversity was leaf age: bacterial richness increased across successional stages, and community composition shifted modestly with age, including taxa more consistently associated with older leaves. Despite these successional changes in biodiversity and composition, no consistent relationship emerged between bacterial richness and ecosystem-functioning. Together, these findings suggest that iii successional assembly structures diversity without producing a uniform diversity-function relationship at the metacommunity scale.

Citation Style

Ecology

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