Academic journal article The American Midland Naturalist

Establishment of an Invasive Plant Species (Conium Maculatum) in Contaminated Roadside Soil in Cook County, Illinois

Academic journal article The American Midland Naturalist

Establishment of an Invasive Plant Species (Conium Maculatum) in Contaminated Roadside Soil in Cook County, Illinois

Article excerpt

ABSTRACT.-

Interactions between environmental variables in anthropogenically disturbed environments and physiological traits of invasive species may help explain reasons for invasive species' establishment in new areas. Here we analyze how soil contamination along roadsides may influence the establishment of Conium maculatum (poison hemlock) in Cook County, IL, USA. We combine analyses that: (1) characterize the soil and measure concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) where Conium is growing; (2) assess the genetic diversity and structure of individuals among nine known populations; and (3) test for tolerance to heavy metals and evidence for local soil growth advantage with greenhouse establishment experiments. We found elevated levels of metals and PAHs in the soil where Conium was growing. Specifically, arsenic (As), cadmium (Cd), and lead (Pb) were found at elevated levels relative to U.S. EPA ecological contamination thresholds. In a greenhouse study we found that Conium is more tolerant of soils containing heavy metals (As, Cd, Pb) than two native species. For the genetic analysis a total of 217 individuals (approximately 20-30 per population) were scored with 5 ISSR primers, yielding 114 variable loci. We found high levels of genetic diversity in all populations but little genetic structure or differentiation among populations. Although Conium shows a general tolerance to contamination, we found few significant associations between genetic diversity metrics and a suite of measured environmental and spatial parameters. Soil contamination is not driving the peculiar spatial distribution of Conium in Cook County, but these findings indicate that Conium is likely establishing in the Chicago region partially due to its ability to tolerate high levels of metal contamination.

INTRODUCTION

Invasive species can create a multitude of ecological problems. They can drastically alter resource use in ecosystems (Elton, 1958; Vitousek et al., 1996), introduce new diseases and pathogens that can negatively affect native species and human health (Mack et ai, 2000; Juliano and Lounibos, 2005), and change species interactions and ecosystem processes in ways that result in lower levels of biodiversity in the ecosystems they invade (Sakai et ai, 2001; Batten et al., 2006). When humans disturb the environment (through construction, damming rivers, plowing for agriculture, etc.), invasive species often exploit these disturbances by colonizing new areas and dramatically increasing in abundance (Hierro, 2006; Kneitel and Perrault, 2006). Interactions between environmental variables in anthropogenically disturbed environments and physiological traits of invasive species may explain invasive species' range expansions and colonization of new areas. This may be particularly true in urban areas since urban ecosystems and landscapes are highly altered by human activity (Sanderson et al, 2002). Here we investigate how soil contamination along roadsides may influence the establishment of Conium maculatum (poison hemlock) a plant considered invasive elsewhere and recently detected only along roadsides in Cook County, IL, USA.

Studies of soil contamination and plant invasion have explored relationships between concentrations of contaminants such as heavy metals in both soils and in plant tissues of different species growing near mine sites (Bech et al, 1997; Liu et al., 2005), considered how plants may adapt to contaminated substrates to form monospecific patches that may be associated with biological invasions (Henriques and Fernandes, 1991; Urbansky et al., 2000), and examined how contaminants move through urban soils and/or how plants uptake these compounds for potential use as bioindicators of pollution (Mihaljevic et al., 2010; Keane et al., 2001). Genetic studies have reconstructed invasion histories from an analysis of die genetic structure of multiple invasive populations (Dray Jr. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.