INVESTIGADORES
ALBARIÑO ricardo Javier
congresos y reuniones científicas
Título:
Sunlight effect changes a detritus - invertebrate interaction
Autor/es:
ALBARIÑO, R.J.; DÍAZ VILLANUEVA, V.; CANHOTO, C.
Lugar:
Coimbra, Portugal
Reunión:
Conferencia; V Conference of the Plant Litter Processing Forum; 2008
Institución organizadora:
Departamento Zoologia, Coimbra University - IMAR
Resumen:
Current ecological models describing coarse organic matter dynamics in streams do not consider direct sunlight effects on leaf litter conditioning, breakdown and transference throughout the food webs. The aim of this study was to evaluate the effects of two light intensities (shaded and unshaded) on leaf litter colonization by stream microorganisms and its resulting quality as food for a detritus consumer, the shredder Klapopteryx kuscheli. Leaf litter was conditioned for two months in an open reach of a second order stream of the Patagonian Andes using litter bags exposed to or sheltered from direct sunlight. Afterwards, we performed laboratory experiments to test larval consumption, growth, efficiency of food conversion (ECI) and feeding preference fed on both leaf litter treatments in single plastic containers. Leaf litter of the unshaded treatment had three times more Chl a than those of the shaded treatment (t-test, p=0.0006), 50% less fungi biomass (t-test, p=0.014) and no differences in bacterial abundance (t-test, p=0.573). Although larvae did not prefer any food (t-test, p=0.535) and fed at the same rate on both leaf litter treatments (t-test, p=0.554), they attained a two-fold growth rate (twelve days experiment; t-test, p=0.020) and ECI (t-test, p=0.004) on the shade-conditioned food resource. Our study emphasizes the importance of considering sunlight incidence in detritus-based food webs as sunlight may alter pathways of matter and energy transference. Riparian modification induced by human activities in forested catchments increases the potential for sunlight effects on detritus dynamics.