Drivers of plant and arthropod diversity and community structure in a grassland ecosystem
type: CreativeWork
description: Forces operating at different spatial scales are known to influence species coexistence and community organization, although the relative importance of these forces is debated. While niche-based models emphasize the effect of local processes on community structure, regional species pools and dispersal abilities of organisms are also thought to constrain species distributions and community diversity. To discern the roles of local and regional processes in shaping ecological communities, this thesis examines the importance of factors operating at multiple spatial scales in governing plant diversity and arthropod community structure. Plant diversity is generally hypothesized to be limited by local competition/productivity ("niche limitation hypothesis", "NLH"), and/or by regional species pools/dispersal ("species pool hypothesis", "SPH"); however, these factors likely interact and vary over periods of community development, i.e. succession. For my first chapter, I test the relevance of the SPH and NLH in limiting diversity, in addition to testing how the importance of these factors may shift from seed/dispersal constraints to local competition/productivity over gradients of 1) productivity and 2) time. Species availability and soil nutrient (N and P) availability were manipulated via seed and fertilizer additions, respectively, and diversity responses were measured over the first 11 years of succession. Diversity increased with seed addition and increased species availability, in support of the SPH; and decreased with nutrient addition and the amplification of local competition, in support of the NLH. Species availability became less important in determining species richness as local productivity and pressures of competition increased. Also, positive effects of seed addition dampened with time, suggesting that species/dispersal constraints became less important and local competition/microsite availability became more important over succession. Additionally, species ava…
abstract: Forces operating at different spatial scales are known to influence species coexistence and community organization, although the relative importance of these forces is debated. While niche-based models emphasize the effect of local processes on community structure, regional species pools and dispersal abilities of organisms are also thought to constrain species distributions and community diversity. To discern the roles of local and regional processes in shaping ecological communities, this thesis examines the importance of factors operating at multiple spatial scales in governing plant diversity and arthropod community structure. Plant diversity is generally hypothesized to be limited by local competition/productivity ("niche limitation hypothesis", "NLH"), and/or by regional species pools/dispersal ("species pool hypothesis", "SPH"); however, these factors likely interact and vary over periods of community development, i.e. succession. For my first chapter, I test the relevance of the SPH and NLH in limiting diversity, in addition to testing how the importance of these factors may shift from seed/dispersal constraints to local competition/productivity over gradients of 1) productivity and 2) time. Species availability and soil nutrient (N and P) availability were manipulated via seed and fertilizer additions, respectively, and diversity responses were measured over the first 11 years of succession. Diversity increased with seed addition and increased species availability, in support of the SPH; and decreased with nutrient addition and the amplification of local competition, in support of the NLH. Species availability became less important in determining species richness as local productivity and pressures of competition increased. Also, positive effects of seed addition dampened with time, suggesting that species/dispersal constraints became less important and local competition/microsite availability became more important over succession. Additionally, species ava…
author: Pesek, Mari Frances
language: en
keywords: Ecology, Biodiversity, Community assembly, Fertilization, Restoration, Succession
date published: 2013-08-31
date modified: 2026-07-24T02:44:56Z
provider: University of Kansas
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Kansas

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1808/12260