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- Influence of seagrass meadows on nursery and fish provisioning ecosystem services delivered by Ria Formosa, a coastal lagoon in PortugalPublication . Erzini, Karim; Parreira, Filipe; Sadat, Zineb; Castro, Margarida; Bentes, Luis; Coelho, Rui; Gonçalves, Jorge Manuel Santos; Lino, Pedro G.; Martínez-Crego, Begoña; Monteiro, Pedro; Oliveira, Frederico; Ribeiro, Joaquim; de los Santos, Carmen B.; Santos, RuiThis study is the first to evaluate the fish provisioning services of a whole transitional landscape (Ria Formosa lagoon, Portugal), in parallel with the enhancement of growth, survival and production of single cohorts of the most important commercial fish species by vegetated and unvegetated sub-tidal habitats. Based on monthly beach seine samples, total density and biomass of 96 species of fishes were 1.89 and 3.03 times greater in vegetated habitats than unvegetated habitats, respectively. Vegetated habitat enhanced survival in six of eight commercial species for which survival could be estimated in both habitats. The total production of all 12 commercially important species within vegetated habitat was approximately double that of unvegetated habitat, with production enhancement in 7 of 12 species ranging from 1.8 to 169-fold for the vegetated habitats. Within the lagoon, vegetated sub-tidal habitat covers an area 5-fold smaller than unvegetated habitat, yet it accounts for 27.1 % of fish production. Estimated total lifetime economic values of the single cohorts of the 12 commercial species were between 30 million and 59 million EUR. An exceptionally strong year class of the European seabass (Dicentrarchus labrax), a species with higher density and biomass in unvegetated habitat, accounts for the higher overall values per hectare for unvegetated habitat (Low natural mortality (M): EUR 32,844 ha-1; High M: EUR 16,751 ha-1) than for vegetated habitat (Low M: EUR 22,028 ha-1; High M: EUR 10,700 ha-1). These results highlight the enormous importance of temperate coastal lagoons as a nursery and source of recruits for coastal fisheries. Our evaluation of fish provisioning services based on data for individual cohorts of fish for a whole transitional landscape is a stronger and more valid approach for estimating future biomass and value than previous studies based on mean densities and biomasses of fish that did not distinguish between cohorts.
- Biodiversity consequences of Caulerpa prolifera takeover of a coastal lagoonPublication . Parreira, Filipe; Martínez-Crego, Begoña; Lourenço Afonso, Carlos Manuel; Machado, Margarida; Oliveira, Frederico; Gonçalves, Jorge Manuel Santos; Santos, RuiThe genus Caulerpa has attracted much attention because many of its species were introduced into non-native regions and became notoriously invasive. This is the case of Caulerpa prolifera that has been rapidly expanding in Ria Formosa lagoon, taking over the deeper unvegetated soft bottoms and competing with seagrass meadows in the shallower areas. Here we address how C. prolifera invasion may affect the support of biodiversity, and specifically, the provision of habitat and nursery for commercial species by the native habitats of this coastal lagoon. Even though no significant differences in total species richness, diversity and evenness were found between C. prolifera and the native unvegetated habitat, the dissimilarity between these two habitats was highest, mostly driven by the extreme reduction of the gastropod Bittium reticulatum and of the tanaid Apseudopsis formosus. This may implicate changes in the trophic interactions of the ecosystem, for example decreasing the tanaid food source for seahorses, which are presently endangered in the lagoon. On the other hand, the fauna species richness, diversity and evenness were significantly higher in the native seagrass habitat than in C. prolifera. Juveniles of valuable flat and sparid fish were only observed in unvegetated sediments and seagrass meadows, respectively. The aggressive spread of C. prolifera in Ria Formosa may alter the structure of native faunal communities, with likely negative implications on fisheries. Nevertheless, the global biodiversity of the lagoon will not be likely drastically affected unless the seaweed takes over the seagrass meadows.