Dataset Information

The role of kelp crabs as consumers in bull kelp forests-evidence from laboratory feeding trials and field enclosures.

ABSTRACT: The Northern kelp crab (Pugettia producta) and the graceful kelp crab (Pugettia gracilis) are common primary consumers in bull kelp beds near the San Juan Islands (Salish Sea, NE Pacific). In this system, urchins (often considered the most voracious herbivores exerting top-down control on kelp beds) tend to remain sedentary because of the high availability of detrital macroalgae, but the extent to which kelp crabs consume kelp (and other food options) is largely unknown. I conducted four types of laboratory feeding experiments to evaluate kelp crab feeding patterns: (1) feeding electivity between bull kelp (Nereocystis luetkeana) and seven species of co-occurring local macroalgae; (2) feeding electivity on aged vs. fresh bull kelp; (3) feeding preference between N. luetkeana and small snails (Lacuna sp.); and (4) scaling of feeding rate with body size in P. producta and P. gracilis. In choice experiments, P. producta consumed greater mass of N. luetkeana than of other macroalgal species offered and elected to eat fresh bull kelp over aged. However, P. producta also consumed snails (Lacuna sp.), indicating more generalized feeding than previously suspected. Feeding rates for P. producta exceeded the expected 3?4 scaling rule of metabolic rates, indicating that larger P. producta may have a disproportionately large impact on bull kelp. A subtidal field experiment, designed to assess the influence of consumers on juvenile bull kelp net tissue gain, found that only fully enclosed (protected) bull kelp increased in wet mass and blade length. Herbivory by kelp crabs, among other consumers, is likely to play a previously unrecognized role in mediating the growth and survival of this annual kelp species within the Salish Sea.

SUBMITTER: Dobkowski K

PROVIDER: S-EPMC5446772 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The role of kelp crabs as consumers in bull kelp forests-evidence from laboratory feeding trials and field enclosures.

Dobkowski Katie K

PeerJ 20170525

The Northern kelp crab (<i>Pugettia producta</i>) and the graceful kelp crab (<i>Pugettia gracilis</i>) are common primary consumers in bull kelp beds near the San Juan Islands (Salish Sea, NE Pacific). In this system, urchins (often considered the most voracious herbivores exerting top-down control on kelp beds) tend to remain sedentary because of the high availability of detrital macroalgae, but the extent to which kelp crabs consume kelp (and other food options) is largely unknown. I conducte ...[more]

PMID: 28560113

Similar Datasets

Project description:Bull kelp, Nereocystis luetkeana, is an iconic kelp forest species of the Northeast Pacific that provides a wide range of ecosystem services to coastal marine species and society. In northern California, U.S.A., Nereocystis abundance declined sharply in 2014 and has yet to recover. While abiotic and biotic stressors were present prior to 2014, the population collapse highlights the need for a better understanding of how environmental conditions impact Nereocystis. In this study, we used a newly-developed, satellite-based dataset of bull kelp abundance, proxied by canopy cover over 20 years, to test the hypothesis that winter oceanographic conditions determine summer Nereocystis canopy cover. For the years before the collapse (1991 through 2013), wintertime ocean conditions, synthesized in a Multivariate Ocean Climate Indicator (MOCI), were indeed a good predictor of summer Nereocystis canopy cover (R2 = 0.40 to 0.87). We attribute this relationship to the effects of upwelling and/or temperature on nutrient availability. South of Point Arena, California, winter ocean conditions had slightly lower explanatory power than north of Point Arena, also reflective of spring upwelling-driven nutrient entrainment. Results suggest that the Nereocystis gametophytes and/or early sporophytes are sensitive to winter oceanographic conditions. Furthermore, environmental conditions in winter 2014 could have been used to predict the Nereocystis collapse in summer 2014, and for kelp north of Point Arena, a further decline in 2015. Importantly, environmental models do not predict changes in kelp after 2015, suggesting biotic factors suppressed kelp recovery, most likely extreme sea urchin herbivory. Conditions during winter, a season that is often overlooked in studies of biophysical interactions, are useful for predicting summer Nereocystis kelp forest canopy cover, and will be useful in supporting kelp restoration actions in California and perhaps elsewhere in the world.

Dataset Information

The role of kelp crabs as consumers in bull kelp forests-evidence from laboratory feeding trials and field enclosures.

Publications

The role of kelp crabs as consumers in bull kelp forests-evidence from laboratory feeding trials and field enclosures.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets