The concept of ecological conservatism and the characteristics of conservative plant species

Floristic Quality Assessment (FQA) is an expert-based indicator system widely used by scientists and natural areas managers. FQA consists of several metrics that reflect the conservation value of a site based on the composition of the plant community. The core principle underlying FQA is the concept of ecological conservatism, meaning a species’ fidelity to high-quality natural areas and its degree of intolerance to modern anthropogenic disturbances. Although conservatism is the lynchpin of FQA metrics, most FQA research has tested the properties and performances of the metrics overall rather than conservatism alone. Greater knowledge about the characteristics associated with conservatism can improve the understanding of what information is captured by FQA metrics and inform the conservation of conservative plant species. In this dissertation, I advanced knowledge about the characteristics of conservatism. In Chapter 2, I critically compared the FQA system to European indicator value systems, particularly those used to assess human impacts to vegetation. My comparisons revealed that other expert-based bioindicator systems have similar methods, philosophies, and concepts to FQA. Moreover, conservatism diverges from other indicator systems because it appraises conservation value and was fundamentally influenced by the region and zeitgeist of the creators of FQA. Next, I determined whether conservatism was associated with distinct characteristics. In Chapter 3, I tested whether conservatism was correlated to 9 functional traits and responses to fertilizer and mycorrhizal addition in a greenhouse experiment of wetland plants. Functional traits of greenhouse-grown wetland plants were inconsistently related to conservatism. Only 3 out of 9 traits were significantly correlated to conservatism; these were traits associated with large, dominant wetland plants. Conservatism was not associated with growth response to mycorrhizal addition, but there was a modest negative association between conservatism and nutrient addition—though this finding was driven by large invasive wetland species. I used two measures of niche width in Chapter 4 to determine if conservative plants were more ecologically specialized. For both measures of niche width, conservative species were more specialized than intermediately conservative species. Yet, nonconservative species were comparably specialist to conservative ones, suggesting that nonconservative species are not necessarily generalists and could be specialized to disturbed conditions. In Chapter 5, I combined plant species’ county record and spatial data across the Midwest to understand if conservative species had distinct and limited distributions, and to assess potential drivers of their distributions. Conservative species had limited distributions throughout the study region and formed concentrations—or hotspots—of conservatism; counties with higher concentrations of conservative species tended to be more northerly, with greater natural and lower agricultural land cover. In Chapter 6, I related conservatism to commercial availability and commonness using a database of native plants available from commercial plant nurseries. Compared to intermediately conservative species, the most and least conservative species were less frequent and poorly available in the commercial trade. Conservatism is multifaceted and integrative: it is both a subjective framework for ecological appraisal and a concept that correlates to species-level characteristics. I showed that conservatism corresponds to characteristics that are known risk-factors of plant conservation. However, because some results were either null, modest in strength, or nonlinear, the relationships between ecological characteristics and conservatism are complex and context dependent.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Zinnen, Jack

Contributors dc:contributor

• Matthews, Jeffrey W.
• Miller, James R.
• Zaya, David N.
• Spyreas, Greg
• Molano-Flores, Brenda

• ecological indicators
• Floristic Quality
• bioindicators
• native plants
• Floristic natural areas
• monitoring

Statement dc:rights

• Copyright 2022 Jack Zinnen

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/116248

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F116248