Biogeographic and anthropogenic correlates of Aleutian Islands plant diversity: A machine‐learning approach

Abstract

This is the first comprehensive analysis of vascular plant diversity patterns in the Aleutian Islands to identify and quantify the impact of Aleutian Island distance dispersal barriers, geographical, ecological and anthropogenic factors. Data from public Open Access databases, printed floristic accounts, and from collections made by the primary author were used to develop an Aleutian floristic database. The most common plant distribution pattern was “an eastern origin community”, though it compared similarly to the “Western” and “Widespread” distribution pattern. We established an ecological plant community composition class for each island, based on clustering species assemblage dissimilarity measurements (Jaccard Index), and a measurement of phylogenetic dissimilarity (UniFrac). We modelled these composition classes and species richness values in non‐parametric algorithmic models and concepts (data cloning using machine learning, stochastic boosting‐ TreeNet) based on classic and Aleutians‐specific island biogeography hypotheses. Plant species richness is strongly associated with the equilibrium model variables of area and island isolation, as well as distance to the Alaska Peninsula, and island total stream length. Species composition is strongly associated with the landmass groups during the last glacial maximum, maximum island elevation, island isolation and island area. Phylogenetic composition is associated with island area, distance from the islands to the Chukotka Peninsula, maximum island elevation, island geologic age, and island isolation. This study extends the equilibrium theory of island biogeography by including additional drivers of diversity during the Anthropocene, such as the landmass during the LGM, as well as factors that may be related to anthropogenic extinction rate.

Ornithogenic vegetation: How significant has the seabird influence been on the Aleutian Island vegetation during the Holocene?

“…Besides climate, there are a lot of other drivers as well as altitude, area and geological age of islands, soils, oceanic flows, isolation, volcanic activity, human activity, etc. (Garroutte et al., 2018 ; Heusser, 1990 ; Lawson et al., 2008 ; McCord, 1980 ). According to their geography and geology, the Aleutian Islands serve as a model for observing the vegetation history during the Holocene.…”

The Claytonia arctica Complex in Alaska—Analyzing a Beringian Taxonomic Puzzle Using Taxonomic Concepts

“…MORPHOLOGIES IN THE CLAYTONIA ARCTICA COMPLEX While Claytonia arctica occurs widespread in the Russian Far East (e.g., Taimyr, Siberia, Chukotka, Kamchatka, and Wrangel Island;Miller & Chambers, 2006;Carlson et al, 2018), in Alaska it is restricted to few populations along the Aleutian Islands (Agattu, Amchitka, Atka, and Kiska; Garroutte et al, 2018;Jones, pers. comm.…”

Long distance dispersal in the assembly of floras: A review of progress and prospects in North America

“…Additionally, Green et al () proposed that freshwater birds, such as herons, are probably frequently involved in long distance dispersal of dry fruits of grasses and other shore‐edge plants that are not specialized for bird dispersal, and their hypothesis is corroborated by studies of bird gut contents and germination rates of dry fruits following passage through a water bird digestive tract. We believe that North America represents an exceptional system for testing hypothesis of long distance dispersal that can eventually be applied elsewhere, because of the biodiversity of the continent is well‐documented by specimens and observations of extant and extinct species as well as by comprehensive local and regional floristic studies (e.g., Flora of North America Editorial Committee, ff; Graham, , ; Vega et al, ; Spicer & Herman, ; Harris et al, ; Ulloa Ulloa et al, ; Edwards et al, ; Garroutte et al, ; Link‐Perez & Laffan, ; Rodríguez et al, ; Sosa et al ).…”