Abstract Detail

Ecology

Rollinson, Emily [1], Ness, Joshua [2].

Surrounded by increasingly distant things: community phylo-proximity as predictor of invasion dynamics.

Although many plant species are introduced to new regions, only a subset of those introductions lead to the successful establishment and spread of an invasive species. Introduced species that are distantly related to the native plant community may be more likely to successfully invade owing to their avoiding strong competition with closely-related native species as well as the costs associated with acquiring shared natural enemies from related natives. However, the general expectation that similarity will be greatest between a focal taxon and its single closest relative needn't obviate the expectation that important ecological similarities and feedbacks can also occur with other more distantly related species and/or the community as a whole. Here, we contrast the utility of different metrics of relatedness to predict the likelihood that an exotic species will be designated as invasive. We characterized the phylogenetic structure of the plant community at Tumamoc Hill Desert Laboratory, a 350 hectare protected natural area in Tucson, Arizona. This plant community is well-documented, including a complete flora of native and introduced species, as well as first records of the introduced species and their distributions in 1983 and 2005. We follow the author's classifications in the 2005 survey (Bowers et al. 2006) in distinguishing individual exotic plant species as either casual (species that have not formed self-replacing populations but rather depend on repeated introduction for their persistence), naturalized (self-replacing species most likely to be found on disturbed sites or, if more widely distributed, having small populations at the local scale), or invasive (self-replacing species that are ubiquitous and abundant in undisturbed communities). We characterized phylogenetic distance between all pairs of species in the community using a reference mega-tree. For each of the 52 exotic species, we described the phylogenetic proximity to the larger community of 326 native species as the sum of inverse separation time (Community Phylo-Proximity), and proximity to the closest native relative as both separation time and its inverse. Increasing Community Phylo-Proximity decreased the likelihood that an exotic species would be categorized as invasive (logistic regression, whole model X² = 4.5, p = 0.034). That likelihood also increased as distance from nearest neighbor increased, and as the inverse distance from nearest neighbor decreased. Akaike weights favored Community Phylo-Proximity as the best single predictor of invasiveness (AICw = 0.618, 0.286 and 0.096, respectively) and of the categorical designation of casual, naturalized or invasive exotic (AICw = 0.744, 0.199 and 0.058, respectively).

1 - East Stroudsburg University, Department Of Biological Sciences, 200 Prospect Street, East Stroudsburg, PA, 18301, United States
2 - Skidmore College, Biology Department, 815 North Broadway, Saratoga Springs, NY, 12866, United States

Keywords:
Biological invasions
community ecology
phylogenetics
desert.

Presentation Type: Oral Paper
Session: ECO2, Ecology: Invasion Biology
Location: /
Date: Tuesday, July 20th, 2021
Time: 1:15 PM(EDT)
Number: ECO2004
Abstract ID:642
Candidate for Awards:None