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1. SBC LTER: Reef: Long-term experiment: Kelp removal: Invertebrate and algal density

   https://doi.org/10.6073/pasta/0c6c40d38f5143c7d56f61c455f7fe9b  

   Reed, Daniel C; Miller, Robert J (January 2024, Environmental Data Initiative)

   These data describe the abundance of common reef associated species of macro invertebrates and macroalgae within permanent plots of a long-term experiment designed to examine trajectories of change in the structure and productivity of kelp forest communities in response to changes in the frequency and severity of disturbance to giant kelp. The number of individuals of approximately 50 taxa were recorded by divers along 40 m transects within each plot. Small species of macroalgae and macinvertebrates were counted within six permanent 1 m2 quadrats positioned uniformly along the 40 m transect, while larger species were counted within four contiguous 20 m2 sub-sections of each 40 m x 2 m transect. Also included at the quadrat scale are estimates of an average size-related measurement of each species, which was developed specifically for each species for the purpose of estimating its biomass. The experiment was initiated in 2008 at five reef sites along the mainland coast of the Santa Barbara Channel and included an annual kelp removal treatment designed to simulate increases in the frequency and severity of winter wave disturbance and a continual kelp removal treatment that allowed the effects of giant kelp on the community to be evaluated. The last experimental removals of giant kelp occurred in winter 2016 or winter 2017, depending on the site. Data collection continued in all plots until spring 2023 to document the recovery trajectory of the reef fish community following the cessation of experimental kelp removal. 

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2. SBC LTER: Reef: Seasonal Kelp Forest Community Dynamics: Abundance and size of Giant Kelp

   https://doi.org/10.6073/pasta/387497d5319cf8d539226e5b3f9b16ae  

   Reed, Daniel C; Miller, Robert J (January 2025, Environmental Data Initiative)

   These data describe the abundance and size of giant kelp (Macrocystis pyrifera) within permanent plots of SBCLTER's seasonal kelp forest monitoring program to track long-term patterns in species abundance and diversity. The number of giant kelp > 1 m tall were recorded within four contiguous 20 m x 1m permanent plots located within a 40 m x 2 m area. The number of fronds > 1 m tall were counted for each individual and used as an estimate of its size. The experiment was initiated in 2008 at five reef sites along the mainland coast of the Santa Barbara Channel. 

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3. Frequent disturbance to a foundation species disrupts consumer‐mediated nutrient cycling in giant kelp forests

   https://doi.org/10.1002/ecy.70019  

   Peters, Joseph R; Reed, Daniel C; Shrestha, June; Hamilton, Scott L; Burkepile, Deron E (March 2025, Ecology)

   Abstract Structure‐forming foundation species facilitate consumers by providing habitat and refugia. In return, consumers can benefit foundation species by reducing top‐down pressures and increasing the supply of nutrients. Consumer‐mediated nutrient dynamics (CND) fuel the growth of autotrophic foundation species and generate more habitat for consumers, forming reciprocal feedbacks. Such feedbacks are threatened when foundation species are lost to disturbances, yet testing these interactions requires long‐term studies, which are rare. Here, we experimentally evaluated how disturbance to giant kelp, a marine foundation species, affects (1) CND of the forest animal community and (2) nutrient feedbacks that help sustain forest primary production during extended periods of low nitrate. Our experiment involved removing giant kelp annually during the winter for 10 years at four sites to mimic frequent wave disturbance. We paired temporal changes in the forest community in kelp removal and control plots with estimates of taxon‐specific ammonium excretion rates (reef fishes and macroinvertebrates) and nitrogen (N) demand (giant kelp and understory macroalgae) to determine the effects of disturbance on CND as measured by ammonium excretion, N demand by kelp forest macroalgae, and the percentage of nitrogen demand met by ammonium excretion. We found that disturbance to giant kelp decreased ammonium excretion by 66% over the study, mostly due to declines in fishes. Apart from a few fish species that dominated CND, most reef‐associated consumers were unaffected by disturbance. Disturbance to giant kelp reduced its N demand by 56% but increased that of the understory by 147% due to its increased abundance in the absence of a kelp canopy. Overall, disturbance had little effect on the fraction of N demand of macroalgae met by consumer excretion due to the offsetting responses of giant kelp, understory macroalgae, and consumers to disturbance. Across both disturbance regimes, on average, consumers supported 11%–12% of the N required by all kelp forest macroalgae and 48% of N demand by the understory macroalgae (which are confined to the benthos where most reef‐associated consumers reside). Our findings suggest that CND constitutes a considerable contribution of N required in kelp forests, yet nutrient inputs decrease following reductions in essential habitat perpetuated by frequent disturbances. 

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4. SBC LTER: Reef: Seasonal Kelp Forest Community Dynamics: Urchin size frequency distribution

   https://doi.org/10.6073/pasta/504b3efff5d74b28af80dce4ce69e250  

   Reed, Daniel C; Miller, Robert J (January 2025, Environmental Data Initiative)

   These data describe the size frequency distribution of red (Mesocentrotus franciscanus) and purple (Strongylocentrotus purpuratus) sea urchins within permanent plots of SBCLTER's seasonal kelp forest monitoring program to track long-term patterns in species abundance and diversity. The diameter of the test (shell without spines) was recorded to the nearest 0.5 cm for 50 red and 50 purple sea urchins located within a 40 m x 2 m area of each plot. Size frequency data of red and purple sea urchins are not collected in the continual kelp removal plots. When combined with size-mass relationships established in the laboratory these data were used to provide a non-destructive, in situ estimate of the dry mass per unit area of bottom for each species. The experiment was initiated in 2008 at five reef sites along the mainland coast of the Santa Barbara Channel. 

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5. SBC LTER: Reef: Seasonal Kelp Forest Community Dynamics: Invertebrate and algal density

   https://doi.org/10.6073/pasta/15701e29b32a58e01d2ae992a1cf11cb  

   Reed, Daniel C; Miller, Robert J (January 2025, Environmental Data Initiative)

   These data describe the abundance of common reef associated species of macro invertebrates and macroalgae within permanent plots of SBCLTER's seasonal kelp forest monitoring program to track long-term patterns in species abundance and diversity. The number of individuals of approximately 50 taxa were recorded by divers along 40 m transects within each plot. Small species of macroalgae and macinvertebrates were counted within six permanent 1 m2 quadrats positioned uniformly along the 40 m transect, while larger species were counted within four contiguous 20 m2 sub-sections of each 40 m x 2 m transect. Also included at the quadrat scale are estimates of an average size-related measurement of each species, which was developed specifically for each species for the purpose of estimating its biomass. The experiment was initiated in 2008 at five reef sites along the mainland coast of the Santa Barbara Channel. 

   more » « less