Ester Dias

Biological invasions and ecosystem functioning: time to merge

Keywords Biodiversity Biological invasions Ecosystem functioning Ecosystem services WorldConference on Biological Invasions and EcosystemFunctioning BIOLIEFThe movement of species is a key characteristic ofour planet. However, in recent decades, humansincreased the rate and scale of these movements andare responsible for many introductions of non-indig-enous invasive species (NIS) in all types of ecosys-tems, from the tropics to the poles and from terrestrialto aquatic environments (Carlton and Geller 1993;Mack et al. 2000). Initially, these movements werejust between contiguous regions but later theincreased transport of goods and people enlargedthe scale of these introductions. Given the magnitudeof these movements plus social and economicconcerns, research programs on NIS have increasedenormously recently and attracted great scientificinterest (Pysˇek et al. 2008; Pejchar and Mooney2009;Vila` et al. 2010). This theme has been gainingmomentum in theoretical and empirical ecology andis an important topic of research with broad impli-cations in biogeography, genetics, and evolution(Sakai et al. 2001; Sax et al. 2007).Similarly, the discussion about the relationshipbetween biodiversity and ecosystem functioning(BEF) has matured during the last two decades(Chapin et al. 2000; Loreau et al. 2001; Cardinaleet al. 2006; Duffy et al. 2007). Few sub-disciplines inecology have expanded as quickly as BEF, and thisresearch has stimulated the emergence of new theo-retical approaches responsible for advances in ourunderstanding of community and ecosystem ecology(Kinzig et al. 2002; Loreau et al. 2002; Naeem et al.2009). Until the 1990s, and with few exceptions,biodiversity was considered to depend merely onabiotic conditions; however, ecologists subsequentlyrecognized that the properties of ecosystems are alsomediated by biodiversity itself (Chapin et al. 1992).Usually, discussions of BEF focus almost exclusivelyon what happens to ecosystem processes and functionsas species richness declines owing to extinctions(Hooper et al. 2005). This discussion is of great

Structure, growth and production of a remarkably abundant population of the common goby, Pomatoschistus microps (Actinopterygii: Gobiidae)

The common goby, Pomatoschistus microps, is a relevant species from estuarine food webs, playing important roles as predator of polychaetes and crustaceans and as prey for larger fishes and crustaceans. The Minho estuary (NW Portugal) is a relatively well-preserved and productive system. To assess the population structure and production of P. microps in this estuary, monthly samples were undertaken in three different areas along an estuarine gradient in the lower estuary. The density of P. microps varied considerably among seasons and sampling stations, with higher densities occurring in summer and autumn. The lowest densities were found closer to the sea. In general, the density of females was higher than the density of males in all sampling stations, while juveniles were more abundant within a salt marsh area. Compared with other European estuaries, our data showed a remarkable higher density and production values of P. microps. This may be related to the high freshwater input and the low salinities found in this estuary. In addition, we hypothesize that the lower density of the sympatric species P. minutus and the high availability of bivalve shells observed in the Minho estuary may have also contributed to the present results, once P. minutus and P. microps often display a diet overlap and the bivalve shells are crucial for the common goby reproduction.

Benthic food webs support the production of sympatric flatfish larvae in estuarine nursery habitat

Identifying nursery habitats is of paramount importance to define proper management and conservation strategies for flatfish species. Flatfish nursery studies usually report upon habitat occupation, but few attempted to quantify the importance of those habitats to larvae development. The reliance of two sympatric flatfish species larvae, the European flounder Platichthys flesus and the common sole Solea solea, on the estuarine food web (benthic vs. pelagic) was determined through carbon and nitrogen stable isotope analysis. The organic matter sources supporting the production of P. flesus and S. solea larvae biomass originates chiefly in the benthic food web. However, these species have significantly different δ13C and δ15N values which suggests that they prey on organisms that use a different mixture of sources or assimilate different components from similar OM pools (or both).

Allochthonous-derived organic matter subsidizes the food sources of estuarine jellyfish

PEDRO MORAIS, ESTER DIAS, JOANA CRUZ, PAULA CHAINHO, MARIA MANUEL ANGÉLICO, JOSÉ LINO COSTA, ANA B. BARBOSA AND MARIA ALEXANDRA TEODÓSIO*  CCMAR–CENTRE OF MARINE SCIENCES, UNIVERSITY OF ALGARVE, CAMPUS DE GAMBELAS, - FARO, PORTUGAL, DEPARTMENT OF ENVIRONMENTAL SCIENCE, POLICY, AND MANAGEMENT, MULFORD HALL, UNIVERSITY OF CALIFORNIA, BERKELEY, BERKELEY, CA , USA, CIIMAR–INTERDISCIPLINARY