Impacts of climate change on coastal benthic ecosystems

 

Objective 2

Biological responses to warming: the case study of mass mortality events

Task 2.1. Gather quantitative data to assess impacts on populations at NWM basin scale.

For the assessment of impacts of mass mortalities linked to warming on rocky benthic communities we are conducting three main activities:

a) we are quantifying the conservation status of macrobenthic species populations through field surveys in different areas of the NW Mediterranean. We are using rapid assessment methods based on the quantification of easy descriptors such as the percentage of affected colonies using random sampling within populations. These methods are thought to be applied by scientific teams but also by trained recreational divers (see below) allowing in the future to assess the impact of climate change at a NW Mediterranean scale.

b) we are developing, in a joint action with the initiative Observadores del mar (www.observadoresdelmar.es), a web platform to gather information on (1) geographic distribution of main gorgonian species, (2) upper limit distribution of gorgonian populations, and (3)  degree of affected colonies (at different depths ranges) to quantify present impacts. The web platform will be used to inform about the potential impacts of climate change on biodiversity conservation, provide information on how-to conduct field surveys and finally to enter the data gathered by volunteers. We plan to organize a meeting with recreational divers to raise the awareness on the climate change effects and explain how to conduct field surveys on gorgonian populations and integrate the collected data to the database through the web platform.

c) we are reviewing the literature to collect data on main gorgonian distribution areas in the NW Mediterranean.

 

Task 2.2. Define tolerance functions vs. T°C conditions for model species

To define species specific environmental tolerance functions, we are integrating (1) the results of thermotolerance experiments conducted by our group and those available from the literature on macrobenthic species (mainly gorgonian and coral species), (2) dataset on mortality impacts collected by our team during the last decades (e.g. Linares et al. 2005, Garrabou et al. 2009) as well as the data collected within ClimCARES (Task 2.1.) will be related with temperature conditions measured in the field (www.t-mednet.org). As en example of tolerance functions that will be used within ClimCARES we present the results from thermotoelrance experiments for the red gorgonian Paramuricea clavata.

Figure 3. Areas (a) and some of the species (b) investigated during field surveys (c) and batch thermotolerance experiments (d)
to analyse correlations between temperature and mortality rates (e) and define thermotolerance limits (f).

Thermotolerance for the red gorgonian Paramuricea clavata.