Overgrazing of kelp beds along the coast of Norway

Author(s):  
Knut Sivertsen
Keyword(s):  
Ecology ◽  
1980 ◽  
Vol 61 (3) ◽  
pp. 447-453 ◽  
Author(s):  
David O. Duggins

2020 ◽  
pp. 871-871
Author(s):  
R. E. Scheibling ◽  
A. W. Hennigar ◽  
T. Balch
Keyword(s):  

Nature ◽  
1966 ◽  
Vol 211 (5052) ◽  
pp. 951-952 ◽  
Author(s):  
GLADYS STURDY ◽  
WILLIAM H. FISCHER
Keyword(s):  

1997 ◽  
Vol 54 (12) ◽  
pp. 2872-2887 ◽  
Author(s):  
Knut Sivertsen

Sites at 244 locations along the west and north Norwegian coasts were investigated to evaluate whether kelp (Laminaria hyperborea) beds had been overgrazed by the sea urchins Strongylocentrotus droebachiensis and Echinus esculentus in the years 1981-1992. Barren ground communities were found in sheltered and moderately wave-exposed areas mainly in the inner and middle archipelago from Nordmøre (63°N) northwards. Densities of large-sized (adult and intermediate) L. hyperborea were 20.7 individuals ·m-2 in kelp beds and 9.7 individuals ·m-2 in transition areas. Juvenile Laminaria spp. were present at densities of 23.9 individuals ·m-2 in kelp beds, 3.6 individuals ·m-2 in transition areas, 0.0 individuals ·m-2 in barren grounds, and 59.1 individuals ·m-2 in kelp-harvested locations. Both the densities and the mean size of S. droebachiensis in barren grounds decreased northwards. The mean densities were 52.2 and 26.1 individuals ·m-2 for the areas south and north of the Arctic Circle, respectively. Multivariate analysis (CANOCO) showed that seven ``environmental'' factors (i.e., kelp depth gradient, distance (latitude), time of sampling, nematode infection in S. droebachiensis, wave exposure, coastal gradient, and substratum) contributed significantly to variability in the distribution of kelp beds and barren grounds. Species in hard-bottom communities in shallow waters could be divided into three distinct BIOTA.


Author(s):  
JOHN S. STEPHENS ◽  
RALPH J LARSON ◽  
DANIEL J. PONDELLA
Keyword(s):  

Author(s):  
Marybeth Lorbiecki

A little girl in Raytown, Missouri, used to spend part of almost every day in a special place in the woods near her house. The place had a calming effect on her. “Sometimes I go there when I’m mad . . . and then, just with the peacefulness, I’m better. I can come back home happy, and my mom doesn’t even know why.” In his book Last Child in the Woods, Richard Louv recounts the end of this fifth grader’s story. “And then they just cut the woods down. It was like they cut down part of me.” I know this same feeling. When I was her age, I watched the prairiesavannah I loved to explore turned into a housing development, chasing away my friends, the meadowlarks. I watched my aging Irish poet friend, Ken Olsen, try to fight the city to save the little bit of woods next to his house from being turned into an apartment complex. The loss nearly gave him a heart attack … or it did give him one, just not one that could be seen. Another friend mourned for weeks after the city cut down the oak in front of her apartment complex that offered dappled green shade to her fourth-floor home. It’s grief, pure and simple. But with all grief, life goes on, sometimes even when we don’t want it to. And there’s hope in that. The land systems long to rejuvenate, just as we long to have them back. Leopold’s restoration work at the Shack and the Arboretum have expanded exponentially, into every ecosystem on land and even into ocean ecosystems, such as coral reefs, kelp beds, tidal communities, and oyster beds. Because so much damage has been done, this is one of the most vibrant, growing, and needed areas of the Leopold legacy. Steven Brower, a landscape architect and Leopold family historian from Burlington, often walks the woods, caves, and bottomlands where Aldo roamed as a child. Brower’s eyes penetrate the landscapes with a kind of x-ray vision, seeing what once was underneath what is today.


2019 ◽  
Vol 39 (4) ◽  
pp. 436-439 ◽  
Author(s):  
Charles L Griffiths

Abstract The herbivorous amphipod Sunamphitoe robertan. sp. is described from the canopy of kelp beds in False Bay, South Africa. The new species has unusual habits, small family groups burrowing directly into the margins of the swollen primary fronds of the kelp Ecklonia maxima (Osbeck) Papenfuss, 1940. Morphologically, the new species is best distinguished from other species of Sunamphitoe by strong rows of dorsal spines on the outer rami of uropods 1 and 2. These spine rows appear to be employed as ‘drill-bits’ to excavate kelp tissue and create the burrows. Damage to hosts does not appear to be fatal, but requires further investigation.


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