Environmental tolerance of the two invasive species Ciona intestinalis and Codium fragile: their invasion potential along a temperate coast

Environmental tolerance of the two invasive species Ciona intestinalis and Codium fragile: their invasion potential along a temperate coast

Ciona intestinalis and Codium fragile are among the most successful invasive species in marine systems worldwide, and they are currently in the process of expanding their distributional ranges along the Chilean coast. Herein we evaluated whether their tolerance to a wide range of environmental conditions contributes to the invasion potential of these two species. To examine the environmental tolerance and performance (e.g., growth) of these non-indigenous species, unifactorial experiments (8–10 days) were conducted with different environmental factors (solar radiation, salinity and temperature). Based on the results, the potential risk of invasion along the Chilean coast was evaluated for both species using a mechanistic niche modeling approach. Both species can tolerate extensive ranges of the abiotic factors salinity and temperature, with C. intestinalis being more tolerant to cold-temperate waters. Also, C. intestinalis was more susceptible to high light intensities than C. fragile. These results confirm those of other experiments, and the outcome of the niche modeling shows that both species can potentially invade most regions of the Chilean coast with the exception of the Magellan region. The results suggest that physiological capacity to tolerate and perform in a wide range of physical conditions is a pre-requisite for successful invasions by littoral biota, but predation and possibly competitive exclusion can slow down the invasion success of C. intestinalis, which in contrast to C. fragile, is consumed by many benthic predators. Sexual and asexual reproduction as well as buoyancy of its thalli further contribute to the dispersal and colonization success of C. fragile. Based on these considerations, it is concluded that the invasion risk of C. fragile along the Chilean coast is substantially higher than that of C. intestinalis.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s