scholarly journals Understanding the Dynamics of Kelp Forest Recovery from Fishing

2021 ◽  
Vol 102 (3) ◽  
Author(s):  
Robert Dunn
Keyword(s):  
2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards

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.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Guri Sogn Andersen ◽  
Henning Steen ◽  
Hartvig Christie ◽  
Stein Fredriksen ◽  
Frithjof Emil Moy

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.


2013 ◽  
Vol 488 ◽  
pp. 119-132 ◽  
Author(s):  
CW Fagerli ◽  
KM Norderhaug ◽  
HC Christie

2021 ◽  
Author(s):  
Jorge Arroyo-Esquivel ◽  
Marissa L Baskett ◽  
Meredith McPherson ◽  
Alan Hastings

In restoration ecology, the Field of Dreams Hypothesis posits that restoration efforts that create a suitable environment could lead to eventual recovery of the remaining aspects of the ecosystem through natural processes. Natural processes following partial restoration has lead to ecosystem recovery in both terrestrial and aquatic systems. However, understanding the efficacy of a "field of dreams" approach requires comparison of different approaches to partial restoration in terms of spatial, temporal, and ecological scale to what would happen with more comprehensive restoration efforts. We explore the relative effect of partial restoration and ongoing recovery on restoration efficacy with a dynamical model based on temperate rocky reefs in Northern California. We analyze our model for both the ability and rate of bull kelp forest recovery under different restoration strategies. We compare the efficacy of a partial restoration approach with a more comprehensive restoration effort by exploring how kelp recovery likelihood and rate change with varying intensities of urchin removal and kelp outplanting over different time periods and spatial scales. We find that, for the case of bull kelp forests, setting more favorable initial conditions for kelp recovery through implementing both urchin harvesting and kelp outplanting at the start of the restoration project has a bigger impact on the kelp recovery rate than applying restoration efforts through a longer period of time. Therefore partial restoration efforts, in terms of spatial and temporal scale, can be significantly more effective when applied across multiple ecological scales in terms of both the capacity and rate of achieving the target outcomes.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
L. Rogers-Bennett ◽  
C. A. Catton

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.


2000 ◽  
Vol 34 (2) ◽  
pp. 48-49
Author(s):  
Don Brutzman
Keyword(s):  

2021 ◽  
Author(s):  
Andrew Rassweiler ◽  
Daniel K. Okamoto ◽  
Daniel C. Reed ◽  
David J. Kushner ◽  
Donna M. Schroeder ◽  
...  

2021 ◽  
Author(s):  
Jorge Luis Montero-Muñoz ◽  
Carmen Ureña ◽  
Diego Navarro ◽  
Valentín Herrera ◽  
Pilar Alonso-Rojo ◽  
...  

Abstract Aims We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by Quercus suber in its lower limits of rainfall and temperature. Two hypotheses were established: (1) regeneration of Quercus species is strongly favored by the presence of tree cover; and (2) growth of Q. suber is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge. Methods We selected woodlands and old fields with and without tree remnants (n = 3 per type), and analyzed stand structure, soil parameters and tree growth. Results Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in Quercus recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September. Conclusions Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of Q. suber where Q. ilex is increasing in abundance. Although temperature has a positive effect on the tree growth of Q. suber, when demographic processes are considered, decreases in water availability likely play a critical role in Q. ilex recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.


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