Date of Submission

Spring 2024

Academic Program

Biology

Project Advisor 1

Cathy Collins

Abstract/Artist's Statement

Diversity of species is unevenly distributed globally and within environments, with some ecosystems containing hundreds of species, and others containing very few. Explaining this ‘biodiversity paradox’ is one objective of ecology. The hypothesis that ‘diversity begets diversity’ (DBD) posits that biodiversity creates conditions that enable even more diversity at a later point in time. Research from multiple systems, especially plant communities, has shown that diversity can encourage further diversification of the habitat through interactions that ameliorate the environment and create more niche space. However, community interactions are highly complex, and any habitat will eventually reach a saturation point where no more species can be accommodated. Systems where communities experience a drastic loss in diversity offer opportunities to study how different levels of species richness affect community assembly. In this study, I asked whether local sites with high diversity after a disturbance will maintain comparatively higher diversity through time, even if species composition changes, and even though overall diversity is expected to increase through succession.

To answer this question, I used a long-term ecological dataset from Mount St Helens to explore the effects of diversity on future diversity. I analyzed how diversity changes within and among sites among three disturbance levels at Mount St Helens over the course of three decades. I expected plots with relatively high richness would accumulate more species, while plots with comparatively few species would see the opposite trend. I explored how richness changed between adjacent pairs of years to determine if high richness in one year is correlated with an increase the following year. Contrary to my predictions, I found the opposite: sites with more species tended to lose species the following year, and sites with low richness tended to increase. However, gains and losses were small, and the number of species per plot often stayed constant year to year.

Open Access Agreement

On-Campus only

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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