Between-habitat variability in the population dynamics of a global marine invader may drive management uncertainty

Graham Epstein,Dan A Smale

doi:10.1016/j.marpolbul.2018.10.055

Abstract

Understanding population dynamics of established invasive species is important for designing effective management measures and predicting factors such as invasiveness and ecological impact. The kelp Undaria pinnatifida has spread to most temperate regions of the world, however a basic understanding of population dynamics is lacking for many regions. Here, Undaria was monitored for 2 years, at 9 sites, across 3 habitats to investigate habitat-related variation in population structure, reproductive capacity and morphology. Populations on marina pontoons were distinct from those in reef habitats, with extended recruitment periods and higher abundance, biomass, maturation rates and fecundity; potentially driven by lower inter-specific and higher intra-specific competition within marinas. This suggests that artificial habitats are likely to facilitate the spread, proliferation and reproductive fitness of Undaria across its non-native range. More broadly, generalising population dynamics of invasive species across habitat types is problematic, thus adding high complexity to management options.

Highlights

The spread of invasive non-native species (INNS) is recognised as a major threat to global biodiversity and the provision of ecological goods and services
During the site selection process, visual searches of the low intertidal zone were conducted across the Plymouth waterfront and at Mount Batten (Fig. 1); subtidal searches were conducted at 7 sites across the same area by SCUBA; while site visits and discussions for permissions to work at marinas were conducted at 4 locations (Fig. 1)
Undaria was recorded at all sites during every sampling event, with the exception of a single instance in the intertidal reef habitat at Firestone Bay, in December 2016

Summary

Introduction

The spread of invasive non-native species (INNS) is recognised as a major threat to global biodiversity and the provision of ecological goods and services. If an INNS is not removed, it is likely to increase its geographical range, population size and propagule pressure over time Where this occurs, management activities may be constrained to limiting the size of populations or reducing their spread (Fraser et al, 2006; Hulme, 2006; Simberloff et al, 2013). Management activities may be constrained to limiting the size of populations or reducing their spread (Fraser et al, 2006; Hulme, 2006; Simberloff et al, 2013) In these situations, information on the biology and ecology of an INNS is critical for effectively designing and implementing management measures (Sakai et al, 2001; Simberloff, 2003)

Methods

Results

Discussion

Conclusion