Abstract Detail

Ecology

Grewell, Brenda [1], Gallego-Tévar, Blanca [2], Whitcraft, Christine R. [3], Futrell, Caryn J. [4], Bárcenas-Moreno, Gael [5], Castillo, Jesús M. [6].

Phenotypic trait differences between native and naturalized Iris pseudacorus across estuarine gradients support increased vigor of invasive populations.

Biological invasions by alien plant species are a global change factor linked to declines in native species diversity and ecosystem functions. Invasive populations often grow more vigorously than conspecific populations in the native range. Adaptive evolution may involve functional plant traits that support invasiveness. Our study focused on comparison of Iris pseudacorus L. (yellow flag iris; Iridaceae) from populations in tidal wetlands distributed along estuarine gradients in the native European range (Guadalquivir River Estuary; Andalusia, Spain) and the invaded North American range (San Francisco Bay-Delta Estuary; California, USA). We aimed to test whether functional traits of alien I. pseudacorus explain its invasive success compared to its growth and fitness in the native range, and to evaluate whether environmental factors explain the phenotypic differences. We compared fifteen morphological, biochemical, and reproductive plant traits and explored their relationships to several environmental factors. We also performed a common-garden experiment to determine if phenotypic differences recorded in the field were maintained in common conditions. We hypothesized that plants of invasive populations would show increases in traits compared to native plants, and these phenotypic differences would be related to contrasted environmental conditions and potential genetic differentiation. Our results reveal that invasive I. pseudacorus plants in California were more robust than those from the native range. The vigor of the invasive plants was reflected by higher specific leaf area (SLA) and leaf water content, lower numbers of senescent leaves, more rhizome carbon reserves, higher fruit and seed production, and greater seed mass than expression of these traits by native plants. Some plant traits showing significant differences in field sites between geographic ranges were markedly related to variation in environmental conditions, but other plant traits differing geographically were independent of every recorded environmental factor. In addition, differences in two plant traits (SLA; number of senescent leaves per sprout) recorded between distribution ranges in the field were retained in common-garden conditions. These results point to phenotypic differences between native and invasive plants as the product of contrasted differences in environmental conditions and genetic processes underlying the introduction of I. pseudacorus. I. pseudacorus plants in their invaded range were more robust and less sensitive to salinity than those growing in its native range. The suite of quantitative functional traits identified in our study may contribute to the ability of I. pseudacorus to transition from initial introduction to invasive status across a wide range of changing environmental conditions. Specific knowledge of these trait responses can be applied to achieve conservation goals aimed at improving predictive risk assessments and management priorities for ecosystem recovery.

1 - USDA-ARS Invasive Species & Pollinator Health Research Unit, Plant Sciences MS-4, University of California, Davis, 1 Shields Ave. , Davis, CA, 95616, USA
2 - Universidad de Sevilla, Dept. Biología Vegetal y Ecología, Universidad de Sevilla, Ap 1095, 41080 Sevilla, Spain
3 - California State University Long Beach, Department of Biological Sciences, 1250 Bellflower Blvd. , Long Beach, CA, 90840, USA
4 - USDA ARS Invasive Species & Pollinator Health Research Unit, Plant Sciences MS-4, University of California, Davis, 1 Shields Ave., Davis, CA, 95616, USA
5 - Universidad de Sevilla, Soil Research Group, Soil Research Group. Department of Cristallography, Mineralogy and Agricultural Chemistry, Chemistry Bldg, C/Profesor García González, 1, 41012 Sevilla, Spain
6 - Universidad de Sevilla, Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Ap. 1095, 41080 Sevilla, Spain

Keywords:
conservation
biological invasions
invasive species
functional traits
Plant invasion
weed risk assessment.

Presentation Type: Oral Paper
Number: EC09001
Abstract ID:583
Candidate for Awards:None