More Like this

1. A marine protected area network does not confer community structure resilience to a marine heatwave across coastal ecosystems

   https://doi.org/10.1111/gcb.16862  

   Smith, Joshua G. ; Free, Christopher M. ; Lopazanski, Cori ; Brun, Julien ; Anderson, Clarissa R. ; Carr, Mark H. ; Claudet, Joachim ; Dugan, Jenifer E. ; Eurich, Jacob G. ; Francis, Tessa B. ; et al ( July 2023 , Global Change Biology)

   Marine protected areas (MPAs) have gained attention as a conservation tool for enhancing ecosystem resilience to climate change. However, empirical evidence explicitly linking MPAs to enhanced ecological resilience is limited and mixed. To better understand whether MPAs can buffer climate impacts, we tested the resistance and recovery of marine communities to the 2014–2016 Northeast Pacific heatwave in the largest scientifically designed MPA network in the world off the coast of California, United States. The network consists of 124 MPAs (48 no‐take state marine reserves, and 76 partial‐take or special regulation conservation areas) implemented at different times, with full implementation completed in 2012. We compared fish, benthic invertebrate, and macroalgal community structure inside and outside of 13 no‐take MPAs across rocky intertidal, kelp forest, shallow reef, and deep reef nearshore habitats in California's Central Coast region from 2007 to 2020. We also explored whether MPA features, including age, size, depth, proportion rock, historic fishing pressure, habitat diversity and richness, connectivity, and fish biomass response ratios (proxy for ecological performance), conferred climate resilience for kelp forest and rocky intertidal habitats spanning 28 MPAs across the full network. Ecological communities dramatically shifted due to the marine heatwave across all four nearshore habitats, and MPAs did not facilitate habitat‐wide resistance or recovery. Only in protected rocky intertidal habitats did community structure significantly resist marine heatwave impacts. Community shifts were associated with a pronounced decline in the relative proportion of cold water species and an increase in warm water species. MPA features did not explain resistance or recovery to the marine heatwave. Collectively, our findings suggest that MPAs have limited ability to mitigate the impacts of marine heatwaves on community structure. Given that mechanisms of resilience to climate perturbations are complex, there is a clear need to expand assessments of ecosystem‐wide consequences resulting from acute climate‐driven perturbations, and the potential role of regulatory protection in mitigating community structure changes.

    

   more » « less
2. Biogeographic patterns of communities across diverse marine ecosystems in southern California

   https://doi.org/10.1111/maec.12453  

   Claisse, Jeremy T. ; Blanchette, Carol A. ; Dugan, Jenifer E. ; Williams, Jonathan P. ; Freiwald, Jan ; Pondella, II, Daniel J. ; Schooler, Nicholas K. ; Hubbard, David M. ; Davis, Kathryn ; Zahn, Laurel A. ; et al ( May 2018 , Marine Ecology)

   Integrating results from monitoring efforts conducted across diverse marine ecosystems provides opportunities to reveal novel biogeographic patterns at larger spatial scales and among multiple taxonomic groups. We investigated large‐scale patterns of community similarity across major taxonomic groups (invertebrates, fishes or algae) from a range of marine ecosystems (rocky intertidal, sandy intertidal, kelp forest, shallow and deep soft‐bottom subtidal) in southern California. Because monitoring sites and methods varied among programs, site data were averaged over larger geographic regions to facilitate comparisons. For the majority of individual community types, locations that were geographically near or environmentally similar to one another tended to have more similar communities. However, our analysis found that this pattern of within community type similarity did not result in all pairs of these community types exhibiting high levels of cross‐community congruence. Rocky intertidal algae communities had high levels of congruence with the spatial patterns observed for almost all of the other (fish or invertebrate) community types. This was not surprising given algal distributions are known to be highly influenced by bottom‐up factors and they are important as food and habitat for marine fishes and invertebrates. However, relatively few pairwise comparisons of the spatial patterns between a fish community and an invertebrate community yielded significant correlations. These community types are generally comprised of assemblages of higher trophic level species, and additional ecological and anthropogenic factors may have altered their spatial patterns of community similarity. In most cases pairs of invertebrate community types and pairs of fish community types exhibited similar spatial patterns, although there were some notable exceptions. These findings have important implications for the design and interpretation of results of long‐term monitoring programs.

    

   more » « less
3. Characterization and spatial variation of the deep-sea fish assemblages on Pioneer Bank, Northwestern Hawaiian Islands

   https://doi.org/10.3354/meps14071  

   Mejía-Mercado, BE ; Baco, AR ( June 2022 , Marine Ecology Progress Series)

   Knowledge of the spatial variation of deep-sea fish assemblages is a critical gap in understanding seamount ecology. Pioneer Bank in the Papahānaumokuākea Marine National Monument (Hawaii, USA) has a history of hook-and-line fishing but not trawling; thus, it is a good location to further describe deep-sea fish assemblages. From replicated autonomous underwater vehicle transects at 300, 450, and 600 m on 3 sides of Pioneer Bank, we observed 4190 fish representing 81 species. Fish assemblages were dominated by Gadiformes, Perciformes, and Stomiiformes. The relative abundance of fish was significantly different among sides of the seamount and the interaction of side and depth, with the NW side having the highest relative abundance at 450 m. Species richness, rarefaction estimates of expected species richness, Shannon diversity, and Simpson dominance showed significant differences by side, but not by depth. These differences were between the S and NW sides, with the S side having the lowest diversity and high dominance. The structure of the fish assemblage was significantly different among both sides and depths, with depth as the most important factor. Fish assemblage structure was most strongly correlated with salinity, % rugosity, chlorophyll a , and mean direction of substrate. These scales of spatial variability both with depth and across short horizontal distances on a single seamount are similar to those found on nearby Necker Island, which reaffirms the spatial heterogeneity in deep-sea fish assemblages on seamounts. This study provides an ecological baseline for the management and conservation of seamounts. 

   more » « less
4. Long-Term Monitoring Reveals Differential Responses of Mussel and Host Fish Communities in a Biodiversity Hotspot

   https://doi.org/10.3390/d13030122  

   Sanchez Gonzalez, Irene ; Hopper, Garrett W. ; Bucholz, Jamie ; Atkinson, Carla L. ( March 2021 , Diversity)

   null (Ed.)

   Biodiversity hotspots can serve as protected areas that aid in species conservation. Long-term monitoring of multiple taxonomic groups within biodiversity hotspots can offer insight into factors influencing their dynamics. Mussels (Bivalvia: Unionidae) and fish are highly diverse and imperiled groups of organisms with contrasting life histories that should influence their response to ecological factors associated with local and global change. Here we use historical and contemporary fish and mussel survey data to assess fish and mussel community changes over a 33 year period (1986–2019) and relationships between mussel abundance and their host fish abundance in Bogue Chitto Creek, a tributary of the Alabama River and a biodiversity hotspot. Mussel abundance declined by ~80% and community composition shifted, with eight species previously recorded not found in 2019, and a single individual of the endangered Pleurobema decisum. Fish abundances increased and life history strategies in the community appeared stable and there was no apparent relationship between mussel declines and abundance of host fish. Temporal variation in the proportion of life history traits composing mussel assemblages was also indicative of the disturbances specifically affecting the mussel community. However, changes and declines in mussel assemblages in Bogue Chitto Creek cannot be firmly attributed to any specific factor or events because of gaps in historical environmental and biological data. We believe that mobility differences contributed to differential responses of fish and mussel communities to stressors including habitat degradation, recent droughts and invasive species. Overall, our work indicates that monitoring biodiversity hotspots using hydrological measurements, standardized survey methods and monitoring invasive species abundance would better identify the effects of multiple and interactive stressors that impact disparate taxonomic groups in freshwater ecosystems. 

   more » « less
5. Geographic variation in responses of kelp forest communities of the California Current to recent climatic changes

   https://doi.org/10.1111/gcb.15273  

   Beas‐Luna, Rodrigo ; Micheli, Fiorenza ; Woodson, C. Brock ; Carr, Mark ; Malone, Dan ; Torre, Jorge ; Boch, Charles ; Caselle, Jennifer E. ; Edwards, Matt ; Freiwald, Jan ; et al ( September 2020 , Global Change Biology)

   The changing global climate is having profound effects on coastal marine ecosystems around the world. Structure, functioning, and resilience, however, can vary geographically, depending on species composition, local oceanographic forcing, and other pressures from human activities and use. Understanding ecological responses to environmental change and predicting changes in the structure and functioning of whole ecosystems require large‐scale, long‐term studies, yet most studies trade spatial extent for temporal duration. We address this shortfall by integrating multiple long‐term kelp forest monitoring datasets to evaluate biogeographic patterns and rates of change of key functional groups (FG) along the west coast of North America. Analysis of data from 469 sites spanning Alaska, USA, to Baja California, Mexico, and 373 species (assigned to 18 FG) reveals regional variation in responses to both long‐term (2006–2016) change and a recent marine heatwave (2014–2016) associated with two atmospheric and oceanographic anomalies, the “Blob” and extreme El Niño Southern Oscillation (ENSO). Canopy‐forming kelps appeared most sensitive to warming throughout their range. Other FGs varied in their responses among trophic levels, ecoregions, and in their sensitivity to heatwaves. Changes in community structure were most evident within the southern and northern California ecoregions, while communities in the center of the range were more resilient. We report a poleward shift in abundance of some key FGs. These results reveal major, ongoing region‐wide changes in productive coastal marine ecosystems in response to large‐scale climate variability, and the potential loss of foundation species. In particular, our results suggest that coastal communities that are dependent on kelp forests will be more impacted in the southern portion of the California Current region, highlighting the urgency of implementing adaptive strategies to sustain livelihoods and ensure food security. The results also highlight the value of multiregional integration and coordination of monitoring programs for improving our understanding of marine ecosystems, with the goal of informing policy and resource management in the future.

    

   more » « less