Monitoring the resilience of a no-take marine reserve to a range extending species using benthic imagery

Abstract

Global climate change is driving the redistribution of marine species and thereby potentially restructuring endemic communities. Understanding how localised conservation measures such as protection from additional human pressures can confer resilience to ecosystems is therefore an important area of research. Here, we examine the resilience of a no-take marine reserve (NTR) to the establishment of urchin barrens habitat. The barrens habitat is created through overgrazing of kelp by an invading urchin species that is expanding its range within a hotspot of rapid climate change. In our study region, a multi-year monitoring program provides a unique time-series of benthic imagery collected by an Autonomous Underwater Vehicle (AUV) within an NTR and nearby reference areas. We use a Bayesian hierarchical spatio-temporal modelling approach to estimate whether the NTR is associated with reduced formation of urchin barrens, and thereby enhances local resilience. Our approach controls for the important environmental covariates of depth and habitat complexity (quantified as rugosity derived from multibeam sonar mapping), as well as spatial and temporal dependence. We find evidence for the NTR conferring resilience with a strong reserve effect that suggests improved resistance to the establishment of barrens. However, we find a concerning and consistent trajectory of increasing barrens cover in both the reference areas and the NTR, with the odds of barrens increasing by approximately 32% per year. Thus, whereas the reserve is demonstrating resilience to the initial establishment of barrens, there is currently no evidence of recovery once barrens are established. We also find that depth and rugosity covariates derived from multibeam mapping provide useful predictors for barrens occurrence. These results have important management implications as they demonstrate: (i) the importance of monitoring programs to inform adaptive management; (ii) that NTRs provide a potential local conservation management tool under climate change impacts, and (iii) that technologies such as AUVs and multibeam mapping can be harnessed to inform regional decision-making. Continuation of the current monitoring program is required to assess whether the NTR can provide long term protection from a phase shift that replaces kelp with urchin barrens.

Enhancing marine resilience in temperate coastal systems requires the implementation of multiple management strategies

“…However, these interventions are primarily implemented in areas with a certain level of protection or designed to preserve iconic species such as Posidonia oceanica in the Mediterranean Sea (Balaguer et al, 2011). Indeed, the establishment of marine protected areas, specifically no-take zones, both recreational and professional, where anthropogenic activities are completely prohibited has proven to enhance and conserve marine resilience (Edgar et al, 2014; Bates et al, 2014; Perkins et al, 2020). However, solely focusing on restricting anthropogenic activities in protected areas hinders the increase of resilience in those areas lacking protection and that are already highly affected by anthropogenic physical impacts.…”

Simple Floating Ocean Wave Energy Converter: Developing Teaching Media to Communicating Alternative Energy

“…Based on data from the Ministry of Energy and Mineral Resources of the Republic of Indonesia, there is a 100% increase in electricity consumption from 2007 of 0.6 KWH/capita to 1.2 KWH/capita in 2020. This shows that there has been massive exploitation of coal in the last few decades, where the number of new rock reserves is limited to use, so it is predicted that these reserves will run out in the next 16 years (Perkins et al, 2020;Welsby et al, 2021;Zhao & Luo, 2018). Therefore, this situation requires alternative steps to anticipate the energy supply shortage for community needs.…”

Effects of anthropogenic stressors on temperate mesophotic ecosystems

“…Importantly, like shallow-water ecosystems, TMEs are also threatened by a wide range of anthropogenic stressors, including ocean warming, ocean acidification, urbanisation, the arrival of non-indigenous species, and fishing activity including trawling (Gennaro and Piazzi, 2011;Cerrano et al, 2013;Bo et al, 2014;Rossi et al, 2017, Ferrigno et al, 2018Marzloff et al, 2018;Enrichetti et al, 2019a;Turner et al, 2019;Betti et al, 2020). Nonetheless, there have been only a few reports of changes in TME communities, which have been linked to wastewater discharge (Hong, 1983;Roberts et al, 1998), heatwaves (Cerrano et al, 2000;Garrabou et al, 2009), shifts in species distribution patterns due to climate change (Perkins et al, 2020) and aquaculture-related eutrophication (Haeussermann et al, 2013). However, as TMEs are challenging to access, many changes may have gone unnoticed due to limited baseline data.…”