ISSN:
1573-5141
Keywords:
riparian removal
;
Mediterranean
;
algae
;
bacteria
;
ectoenzymatic activities
;
macroinvertebrates
;
biomass
;
productivity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The effect of removal of a riparian strip on aquaticautotrophic (algae) and heterotrophic (bacteria,macroinvertebrates) organisms was monitored in aMediterranean stream during the canopy growing period.Community composition, biomass and metabolicactivities were compared with those recorded during apre-riparian removal period and in a forested stretchdownstream. Higher irradiance was associated with Cladophora increase in the logged section. Algalbiomass increased up to ten times, and productivitywas up to four times higher than in the pre-removalperiod and the forested section. Bacterialcommunities showed higher ectoenzymatic activities(β-glucosidase, β-xylosidase) in thelogged section than in forested conditions. Moreoverthe coincidence between the maxima ofβ-glucosidase and chlorophyll-a suggeststhat bacterial activity was enhanced by the higheravailability of high-quality algal material. Themacroinvertebrate community had higher density andbiomass in the logged section than in the forestedsection and in the pre-removal period. Scrapers andfilterers become dominant after riparian removal,while shredders, predators and collectors did not showsignificant changes either between sites or periods.Responses of environmental variables and bioticcommunities indicate that the changes occurring in thestream due to riparian removal could be consideredbottom-up controlled, as increased illumination wasthe main mechanism responsible.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009938511352
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