Ecology of exposed sandy beaches in northern Spain: environmental factors controlling macrofauna communities
Lastra, M.; de la Huz, R.; Sánchez-Mata, A.G.; Rodil, I.F.; Aerts, K.; Beloso, S.; Lopéz, J. (2006). Ecology of exposed sandy beaches in northern Spain: environmental factors controlling macrofauna communities. J. Sea Res. 55(2): 128-140. http://dx.doi.org/10.1016/j.seares.2005.09.001
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
|  |
| Keywords |
Aquatic communities > Benthos
Environmental factors
Gradients
Habitat > Exposed habitats
Topographic features > Landforms > Coastal landforms > Beaches
ANE, Spain [Marine Regions]
Marine/Coastal |
| Author keywords |
sandy beaches; macrofauna; environmental factors; beach morphodynamics;geographical gradients; north Spain |
| Authors | | Top |
- Lastra, M.
- de la Huz, R.
- Sánchez-Mata, A.G.
- Rodil, I.F.
|
- Aerts, K., more
- Beloso, S.
- Lopéz, J.
|
|
| Abstract |
Thirty-four exposed sandy beaches on the northern coast of Spain (from 42°11′ to 43°44′N, and from 2°04′ to 8°52′ W; ca. 1000 km) were sampled over a range of beach sizes, beach morphodynamics and exposure rates. Ten equally spaced intertidal shore levels along six replicated transects were sampled at each beach. Sediment and macrofauna samples were collected using corers to a depth of 15 cm. Morphodynamic characteristics such as the beach face slope, wave environment, exposure rates, Dean's parameter and Beach State Index were estimated. Biotic results indicated that in all the beaches the community was dominated by isopods, amphipods and polychaetes, mostly belonging to the detritivorous-opportunistic trophic group. The number of intertidal species ranged from 9 to 31, their density being between 31 and 618 individuals m-2, while individuals per linear metre (m-1) ranged from 4962 to 17 2215. The biomass, calculated as total ash-free dry weight (AFDW) varied from 0.027 to 2.412 g m-2, and from 3.6 to 266.6 g m-1. Multiple regression analysis indicated that number of species significantly increased with proximity to the wind-driven upwelling zone located to the west, i.e., west-coast beaches hosted more species than east-coast beaches. The number of species increased with decreasing mean grain size and increasing beach length. The density of individuals m-2 increased with decreasing mean grain size, while biomass m-2 increased with increasing food availability estimated as chlorophyll-a concentration in the water column of the swash zone. Multiple-regression analysis indicated that chlorophyll-a in the water column increased with increasing western longitude. Additional insights provided by single-regression analysis showed a positive relationship between the number of species and chlorophyll-a, while increasing biomass occurred with increasing mean grain size of the beach. The results indicate that community characteristics in the exposed sandy beaches studied are affected by physical characteristics such as sediment size and beach length, but also by other factors dependent on coastal processes, such as food availability in the water column. |
|
