2024-03-29T05:04:28Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/372152018-07-13T11:17:50Zcom_10261_88com_10261_8col_10261_341
Effects of riparian vegetation removal on nutrient retention in a Mediterranean stream
Sabater, Francesc
Butturini, Andrea
Martí, Eugènia
Muñoz, I.
Romaní, Anna
Wray, J.
Sabater, Sergi
Algal biomass
Ammonium
Disturbance
Logging
Mediterranean stream
Nitrate
Nutrient retention
Phosphate
Primary production
Riparian vegetation
Riparian zone
Uptake length
12 páginas ; 3 Figuras ; 1 Tabla
We examined the effects of riparian vegetation removal on algal dynamics and stream
nutrient retention efficiency by comparing NH4-N and PO4-P uptake lengths from a logged and an
unlogged reach in Riera Major, a forested Mediterranean stream in northeastern Spain. From June to
September 1995, we executed 6 short-term additions of N (as NH4Cl) and P (as Na2HPO4) in a 200-
m section to measure nutrient uptake lengths. The study site included 2 clearly differentiated reaches
in terms of canopy cover by riparian trees: the first 100 m were completely logged (i.e., the logged
reach) and the remaining 100 m were left intact (i.e., the shaded reach). Trees were removed from
the banks of the logged reach in the winter previous to our sampling. In the shaded reach, riparian
vegetation was dominated by alders (Alnus glutinosa). The study was conducted during summer and
fall months when differences in light availability between the 2 reaches were greatest because of
forest canopy conditions. Algal biomass and % of stream surface covered by algae were higher in
the logged than in the shaded reach, indicating that logging had a stimulatory effect on algae in the
stream. Overall, nutrient retention efficiency was higher (i.e., shorter uptake lengths) in the logged
than in the shaded reach, especially for PO4-P. Despite a greater increase in PO4-P retention efficiency
relative to that of NH4-N following logging, retention efficiency for NH4-N was higher than for PO4-
P in both study reaches. The PO4-P mass-transfer coefficient was correlated with primary production
in both study reaches, indicating that algal activity plays an important role in controlling PO4-P
dynamics in this stream. In contrast, the NH4-N mass-transfer coefficient showed a positive relationship
only with % of algal coverage in the logged reach, and was not correlated with any algal-related
parameter in the shaded reach. The lack of correlation with algal production suggests that mechanisms
other than algal activity (i.e., microbial heterotrophic processes or abiotic mechanisms) may
also influence NH4-N retention in this stream. Overall, this study shows that logging disturbances
in small shaded streams may alter in-stream ecological features that lead to changes in stream nutrient
retention efficiency. Moreover, it emphasizes that alteration of the tight linkage between the
stream channel and the adjacent riparian zone may directly and indirectly impact biogeochemical
processes with implications for stream ecosystem functioning.
2011-06-28T08:45:53Z
2011-06-28T08:45:53Z
2000-12
artículo
Journal of the North American Benthological Society 19(4) : 609-620 (2000)
0887-3593
http://hdl.handle.net/10261/37215
eng
http://www.jnabs.org/doi/abs/10.2307/1468120
closedAccess
North American Benthological Society