scholarly journals Lack of sea urchin settlement may explain kelp forest recovery in overgrazed areas in Norway

2013 ◽  
Vol 488 ◽  
pp. 119-132 ◽  
Author(s):  
CW Fagerli ◽  
KM Norderhaug ◽  
HC Christie
Keyword(s):  
Sea Urchin ◽  
Kelp Forest ◽  
Forest Recovery

scholarly journals Marine heat wave and multiple stressors tip bull kelp forest to sea urchin barrens

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
L. Rogers-Bennett ◽  
C. A. Catton
Keyword(s):  
Sea Urchin ◽  
Large Scale ◽  
Multiple Stressors ◽  
Kelp Forest ◽  
Ocean Warming ◽  
Forest Recovery ◽  
Population Increase ◽  
North Coast ◽  
Sea Stars ◽  
Sea Urchin Barrens

Abstract Extreme climatic events have recently impacted marine ecosystems around the world, including foundation species such as corals and kelps. Here, we describe the rapid climate-driven catastrophic shift in 2014 from a previously robust kelp forest to unproductive large scale urchin barrens in northern California. Bull kelp canopy was reduced by >90% along more than 350 km of coastline. Twenty years of kelp ecosystem surveys reveal the timing and magnitude of events, including mass mortalities of sea stars (2013-), intense ocean warming (2014–2017), and sea urchin barrens (2015-). Multiple stressors led to the unprecedented and long-lasting decline of the kelp forest. Kelp deforestation triggered mass (80%) abalone mortality (2017) resulting in the closure in 2018 of the recreational abalone fishery worth an estimated $44 M and the collapse of the north coast commercial red sea urchin fishery (2015-) worth $3 M. Key questions remain such as the relative roles of ocean warming and sea star disease in the massive purple sea urchin population increase. Science and policy will need to partner to better understand drivers, build climate-resilient fisheries and kelp forest recovery strategies in order to restore essential kelp forest ecosystem services.

Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga

2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards
Keyword(s):  
Field Experiments ◽  
Local Community ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Forest Recovery ◽  
Kelp Forests ◽  
Giant Kelp ◽  
Combined Effects ◽  
Life Stages ◽  
Survival And Growth

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

scholarly journals Kelp forest ecosystems: biodiversity, stability, resilience and future

2002 ◽  
Vol 29 (4) ◽  
pp. 436-459 ◽  
Author(s):  
Robert S. Steneck ◽  
Michael H. Graham ◽  
Bruce J. Bourque ◽  
Debbie Corbett ◽  
Jon M. Erlandson ◽  
...  
Keyword(s):  
Case Studies ◽  
Sea Urchin ◽  
North Atlantic ◽  
Forest Ecosystems ◽  
Kelp Forest ◽  
Kelp Forests ◽  
Apex Predators ◽  
The Past ◽  
The North ◽  
Fishing Impacts

Kelp forests are phyletically diverse, structurally complex and highly productive components of coldwater rocky marine coastlines. This paper reviews the conditions in which kelp forests develop globally and where, why and at what rate they become deforested. The ecology and long archaeological history of kelp forests are examined through case studies from southern California, the Aleutian Islands and the western North Atlantic, well-studied locations that represent the widest possible range in kelp forest biodiversity. Global distribution of kelp forests is physiologically constrained by light at high latitudes and by nutrients, warm temperatures and other macrophytes at low latitudes. Within mid-latitude belts (roughly 40–60° latitude in both hemispheres) well-developed kelp forests are most threatened by herbivory, usually from sea urchins. Overfishing and extirpation of highly valued vertebrate apex predators often triggered herbivore population increases, leading to widespread kelp deforestation. Such deforestations have the most profound and lasting impacts on species-depauperate systems, such as those in Alaska and the western North Atlantic. Globally urchin-induced deforestation has been increasing over the past 2–3 decades. Continued fishing down of coastal food webs has resulted in shifting harvesting targets from apex predators to their invertebrate prey, including kelp-grazing herbivores. The recent global expansion of sea urchin harvesting has led to the widespread extirpation of this herbivore, and kelp forests have returned in some locations but, for the first time, these forests are devoid of vertebrate apex predators. In the western North Atlantic, large predatory crabs have recently filled this void and they have become the new apex predator in this system. Similar shifts from fish- to crab-dominance may have occurred in coastal zones of the United Kingdom and Japan, where large predatory finfish were extirpated long ago. Three North American case studies of kelp forests were examined to determine their long history with humans and project the status of future kelp forests to the year 2025. Fishing impacts on kelp forest systems have been both profound and much longer in duration than previously thought. Archaeological data suggest that coastal peoples exploited kelp forest organisms for thousands of years, occasionally resulting in localized losses of apex predators, outbreaks of sea urchin populations and probably small-scale deforestation. Over the past two centuries, commercial exploitation for export led to the extirpation of sea urchin predators, such as the sea otter in the North Pacific and predatory fishes like the cod in the North Atlantic. The large-scale removal of predators for export markets increased sea urchin abundances and promoted the decline of kelp forests over vast areas. Despite southern California having one of the longest known associations with coastal kelp forests, widespread deforestation is rare. It is possible that functional redundancies among predators and herbivores make this most diverse system most stable. Such biodiverse kelp forests may also resist invasion from non-native species. In the species-depauperate western North Atlantic, introduced algal competitors carpet the benthos and threaten future kelp dominance. There, other non-native herbivores and predators have become established and dominant components of this system. Climate changes have had measurable impacts on kelp forest ecosystems and efforts to control the emission of greenhouse gasses should be a global priority. However, overfishing appears to be the greatest manageable threat to kelp forest ecosystems over the 2025 time horizon. Management should focus on minimizing fishing impacts and restoring populations of functionally important species in these systems.

Food Availability, Sea Urchin Grazing, and Kelp Forest Community Structure

Ecology ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 1160-1169 ◽  
Author(s):  
Christopher Harrold ◽  
Daniel C. Reed
Keyword(s):  
Community Structure ◽  
Food Availability ◽  
Sea Urchin ◽  
Kelp Forest ◽  
Forest Community ◽  
Urchin Grazing

Effects of predators on sea urchin density and habitat use in a southern California kelp forest

2015 ◽  
Vol 162 (6) ◽  
pp. 1227-1237 ◽  
Author(s):  
Kathryn D. Nichols ◽  
Leah Segui ◽  
Kevin A. Hovel
Keyword(s):  
Habitat Use ◽  
Sea Urchin ◽  
Southern California ◽  
Kelp Forest ◽  
Urchin Density

scholarly journals Seasonal Patterns of Sporophyte Growth, Fertility, Fouling, and Mortality ofSaccharina latissimain Skagerrak, Norway: Implications for Forest Recovery

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Guri Sogn Andersen ◽  
Henning Steen ◽  
Hartvig Christie ◽  
Stein Fredriksen ◽  
Frithjof Emil Moy
Keyword(s):  
Seasonal Variations ◽  
Life Stage ◽  
Kelp Forest ◽  
Forest Recovery ◽  
Saccharina Latissima ◽  
Seasonal Patterns ◽  
Study Sites

On the Skagerrak coast the kelpSaccharina latissimahas suffered severe stand reductions over the last decade, resulting in loss of important habitats. In the present study, healthy kelp plants were transplanted into four deforested areas and their patterns of growth, reproduction, and survival were monitored through subsequent seasons. Our main objective was to establish whether the kelp plants were able to grow and mature in deforested areas. We observed normal patterns of growth and maturation at all study sites. However, heavy fouling by epiphytes occurred each summer, followed by high kelp mortality. The study shows that the seasonal variations and the life stage timing ofS. latissimamake formation of self-sustainable populations impossible in the present environment. Most noteworthy, we suggest that fouling by epiphytes is involved in the lack of kelp forest recovery in Skagerrak, Norway.

scholarly journals The sea urchin – the ultimate herbivore and biogeographic variability in its ability to deforest kelp ecosystems

2013 ◽  
Author(s):  
Jarrett E Byrnes ◽  
Ladd E. Johnson ◽  
Sean D. Connell ◽  
Nick T. Shears ◽  
Selena M McMillan ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Large Scale ◽  
Sea Urchins ◽  
Meta Analysis ◽  
Kelp Forest ◽  
Rocky Reef ◽  
Rocky Reefs ◽  
Iconic Images ◽  
Balance Of Forces ◽  
Almost All

Barren rocky seafloor landscapes, denuded of almost all life by ravenous sea urchins, liberated from their predators, stands as one of the iconic images of trophic cascades in Ecology. While this paradigm has been cited in nearly every temperate rocky reef ecosystem across the globe, there is widespread disagreement as to its generality. Given their biology, sea urchins are clearly one of the ocean’s strongest herbivores in many systems, but where will their impact be strongest? Here we perform a global meta-analysis of sea urchin-kelp relationships in the field. We find that sea urchins appear to be able to control kelp abundances in any system where they can achieve high densities. Furthermore, their ability to create large-scale long-lasting barrens appears to be limited to biogeographic regions where they can achieve high consumptive potential. Based on the literature, we outline a conceptual model that examines when and where sea urchins should be able to have a strong regulating impact on kelp forest ecosystems. We suggest that many elements of global change may shift the balance of forces regulating sea urchin consumptive potential in these ecosystems. Given their ability to have strong impacts on temperate rocky reefs, these drivers need to be considered in concert with their effect on sea urchins when attempting to predict future change to marine ecosystems.

Sign in / Sign up

Export Citation Format

Share Document