Search

Starting with the publication of some influential studies in the early 1990s, the topic of biodiversity and ecosystem functioning has emerged as a major field within ecological research. Within this framework, the diversity of genotypes, species and functional groups are considered as explanatory variables of ecosystem functions rather than response variables of factors such as productivity and disturbance. Biodiversityecosystem functioning research has received considerable attention, and new publications are emerging at a high pace. Both the validity of experimental approaches and the way the results may be extrapolated to natural systems have, however, been widely discussed. The width of the debate regarding whether or not biodiversity is important for ecosystem functioning have encouraged many scientists to refine both experiments and theory, as well as develop novel methods to analyse the relationship between diversity and functioning. Aquatic ecologists have contributed greatly to the evolution of ideas and concepts within the field. In this review, we discuss how the paradigm that biodiversity is an important factor for the functioning of aquatic ecosystems is currently maturing with more realistic studies embracing both new and innovative approaches. We also suggest fruitful areas for future research.Each of us is trapped in a place, a time, and a circumstance, and our attempts to use our minds to transcend those boundaries are, more often than not, ineffective.From the book “Stumbling on happiness” by Daniel Gilbert © 2008 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

Ecologists have greatly advanced our understanding of the processes that regulate trophic structure and dynamics in ecosystems. However, the causes of systematic variation among ecosystems remain controversial and poorly elucidated. Contrasts between aquatic and terrestrial ecosystems in particular have inspired much speculation, but only recent empirical quantification. Here, we review evidence for systematic differences in energy flow and biomass partitioning between producers and herbivores, detritus and decomposers, and higher trophic levels. The magnitudes of different trophic pathways vary considerably, with less herbivory, more decomposers and more detrital accumulation on land. Aquatic–terrestrial differences are consistent across the global range of primary productivity, indicating that structural contrasts between the two systems are preserved despite large variation in energy input. We argue that variable selective forces drive differences in plant allocation patterns in aquatic and terrestrial environments that propagate upward to shape food webs. The small size and lack of structural tissues in phytoplankton mean that aquatic primary producers achieve faster growth rates and are more nutritious to heterotrophs than their terrestrial counterparts. Plankton food webs are also strongly size-structured, while size and trophic position are less strongly correlated in most terrestrial (and many benthic) habitats. The available data indicate that contrasts between aquatic and terrestrial food webs are driven primarily by the growth rate, size and nutritional quality of autotrophs. Differences in food-web architecture (food chain length, the prevalence of omnivory, specialization or anti-predator defences) may arise as a consequence of systematic variation in the character of the producer community. [ABSTRACT FROM AUTHOR]