Macro-environmental modelling of the current distribution of Undaria pinnatifida (Laminariales, Ochrophyta) in northern Iberia

Abstract

The Asian kelp Undaria pinnatifida was first reported in north-western Spain in 1988. Since then, it has spread along the Galician coasts and towards the western Cantrabrian coast, probably supported by new introductions related to aquaculture and private yachts. Despite the high potential of this seaweed to invade new areas, it has not fully established itself in specific areas along the eastern Cantabrian coast where it has been farmed. We attempted to identify the macro-environmental determinants for the successful establishment of U. pinnatifida in the northern Iberian coast. Thus, we built a model based on the significant relationships between this kelp and several environmental factors using the Favourability Function, a method based on binary logistic regression. We obtained a statistically significant Favourability model where the chlorophyll concentration in summer was the most influential variable and the photosynthetically active radiation in spring was a secondary variable that best characterized the presence of U. pinnatifida. The ecological implications are discussed.

Status, trends and drivers of kelp forests in Europe: an expert assessment

“…In the specific case of U. pinnatifida, most of its present-day distribution in France seems to be explained by past farming activities of this seaweed which were the triggers for the initial establishment of populations in natural habitats then human-made infrastructures (marinas, seawalls) were important pathways for its spread (Voisin et al 2005;Grulois et al 2011). Aquaculture is also the primary vector of its introduction in Spain (Báez et al 2010). Local expansion has been documented in Brittany, as in UK and Ireland (Heiser et al 2014;Minchin and Nunn 2014;Arnold et al 2016), in the last two decades whereas Mediterranean populations decline, probably as a response to warm temperature and a predicted expansion was not confirmed by field data in Portugal (Veiga et al 2014).…”

Resistance and facilitation by native algal communities in the invasion success of Undaria pinnatifida

“…One of the most invasive macroalgal species is the Japanese kelp Undaria pinnatifida (Harvey) Suringer, which has become established in the temperate zone worldwide (Silva et al 2002, Valentine & Johnson 2003, Edgar et al 2004, Farrell & Fletcher 2006, Martin & Cuevas 2006, Baez et al 2010, Irigoyen et al 2011). This seaweed arrived in New Zealand around 1987 and has since spread throughout much of the South Island (Hay & Villouta 1993, Parsons 1995, Stuart 2004, Russell et al 2008, aided by multiple incursions (Uwai et al 2006).…”

Ecological niche models of invasive seaweeds

“…A correlative presence–absence model based on macroecological predictors was used to identify the factors that determine the successful establishment of Undaria pinnatifida in northern Spain (Báez et al. ). Chl concentration and photosynthetically active radiation (PAR) were suggested to best characterize the distribution of U. pinnatifida in the invaded area.…”

“…Although the relationship between PAR and this species distribution seems odd, as this kelp has low light requirements, this variable is expected to affect the overall number of species, increasing the availability of suitable habitats (e.g., shadowing) for U. pinnatifida (see Báez et al. and references therein). Proximity to urban centers and temperature were also found to be related to the species’ distribution, the latter being especially important when considering the optimum temperatures for the recruitment and development of sporophytes.…”