Título: Beneath the Heat: Unravelling the Impact of Climate Stress and Habitat Fragmentation on the Invasion of Marine Benthic Ecosystems
Resumen: Marine heatwaves (MHWs), consequence of climate change, and habitat fragmentation are key contributors to the transformation of coastal marine habitats. These two stressors affect biodiversity and community structure, reducing the resilience to other coastal threats as e.g. biological invasions. This study seeks to evaluate the individual and combined effects of MHWs and habitat fragmentation on community dynamics, recovery potential and vulnerability to the arrival of non-indigenous species (NIS). Prior to starting the experiment, a total of three Autonomous Reef Monitoring Systems (ARMS) were deployed at the sea bottom for 10 months to collect benthic community samples from the SW Iberian Peninsula: Faro de las Puercas (Gulf of Cádiz). These pre-recruited communities were used to create fragmented and non-fragmented synthetic units to be exposed in a mesocosm experiment simulating moderate (24ºC) and extreme (28ºC) during five consecutive days. After the mesocosm experiment, non-fragmented assemblages were deployed in a marina environment (i.e. high NIS propagule pressure) to assess post-disturbance recovery and potential recruitment of new NIS. Our results indicate that MHWs and habitat fragmentation influence benthic community composition, though their effects on species richness and diversity indices appear limited. Fragmentation altered species assembling patterns, increasing community heterogeneity without necessarily reducing biodiversity. No clear synergistic interaction was observed between MHWs and fragmentation, suggesting that these stressors operate independently. During the secondary marina phase, the presence of NIS recruits suggests that heat-stressed communities may be more vulnerable to invasion. Overall, these findings highlight that while MHWs can drive changes in species composition and habitat fragmentation may reshape structural heterogeneity, their combined effects do not seem to not amplify these changes. The lack of clear interaction between these stressors indicates that community responses are likely driven by species-specific tolerances rather than purely additive or synergistic effects on the overall community assembling.
Congreso: EEI 2025
