Daniel Boix

Patterns of composition and species richness of crustaceans and aquatic insects along environmental gradients in Mediterranean water bodies

Differences in the dynamics of ecological processes between Mediterranean and colder temperate aquatic systems could imply different patterns in faunal communities in terms of composition and biodiversity (i.e. species richness and rarity). In order to identify some of these patterns the crustacean and aquatic insect composition and biodiversity of four water body types, classified according to their salinity and water permanence, were compared. Moreover, the relationships between species richness and water, pond and landscape variables were analysed. A total number of 91 water bodies located throughout Catalunya (NE Iberian Peninsula) were sampled. Three species assemblages were observed: one for permanent freshwaters, another for temporary freshwaters, and a third one for saline waters (SW), since permanent and temporary saline water bodies had similar composition. Differences in salinity were associated with proportion of crustaceans versus insects and with singularity. Thus, saline ponds had a higher proportion of crustaceans, and lower values of singularity. Conductivity was significantly related to total (crustaceans plus insects) richness, and also related to insect richness. The main difference between the models obtained for crustacean species richness and insect species richness is the significance of landscape variables in the latter, and this fact could be related to the different dispersion types of these two faunal groups: active for insects versus passive for crustaceans.

Non-indigenous animal species naturalized in Iberian inland waters

Invasions by human-introduced non-indigenous species (NIS) are one of the main threats to biodiversity and a driving force of global change (Vitousek et al. 1997, Mack et al. 2000, Clavero and Garcia-Berthou 2005). The Iberian Peninsula (IP) is a hotspot of biodiversity (Medail and Quezel 1999) and a knowledge of the invasive species inhabiting it is essential for conservation and environmental management. Naturalized vertebrates and plants in the IP have received considerable attention (see e.g. Vila et al. 2001, Pleguezuelos 2002, Sobrino et al. 2002, Lloret et al. 2004, Alcaraz et al. 2005), but its invasive invertebrates are very poorly known. Although there are many records of some invertebrate invasive species, particularly crustaceans, there are very few available reviews of selected taxa of invertebrate invaders in the IP (e.g. Espadaler and Collingwood 2001). The aim of this chapter is to review the animal species naturalized in Iberian inland waters, including vertebrates and free-living and parasitic invertebrates. As usual, the taxonomy and biogeography of vertebrate species are much better known than for invertebrates, so our data for invertebrates should be regarded as a preliminary check-list. Similarly, the parasites of non-commercial aquatic species are poorly studied and the data in the IP mostly come from studies of the eel, Anguilla anguilla (Linnaeus), thus certainly underestimating the range of introduced parasites (Blanc 1997, 2001). We feel, however, that it is important to provide such a

Environmental filtering determines community patterns in temporary wetlands: A multi-taxon approach

Climate characteristics appear to play a key role in filtering organisms based on their biological traits. If this trait filtering by climate indeed occurs, it should have effects on the composition, dynamics, taxonomic relatedness and co-occurrence patterns of local assemblages, regardless of the taxonomic group considered. This preliminary study aimed to assess the extent to which environmental variables might determine these patterns in local communities and to evaluate whether the ultimate cross-taxon congruence relationships are consistent across, or dependent on, the selected region. To this end, we studied the bryophyte, macrophyte, macroinvertebrate, and amphibian communities in two clusters of temporary wetlands on the NE Iberian Peninsula under mesothermal and semiarid climates. We observed effects of environmental filtering, with the communities differing between the climatic regions not only in their compositions but also in their dynamics and taxonomic relatedness patterns. Although the cross-taxon congruence in terms of species richness was high in the mesothermal climate, most of the congruent relationships were disrupted in the semiarid environment. Overall, because climate-dependent patterns appear to prevail over climate-consistent ones, we suggest that the use of surrogate taxa may be of limited value when aiming to assess wetland biodiversity across large areas.

Change in biological traits and community structure of macroinvertebrates through primary succession in a man-made Swedish wetland

Abstract.  We investigated the successional development of a benthic macrofaunal community in Kalmar Dämme, a man-made wetland in southeastern Sweden, over a 13-y period after construction (1997–2009). We assessed primary succession by monitoring changes in species composition, biological traits, and community structure. Predictable successional changes occurred, and the structure of the community was complex at the advanced phase. Three successional phases were observed, each with typifying species. At the advanced phase, dominant biological traits shifted to favor animals with longer life-cycle durations, aerial dispersal strategies, and certain feeding types (i.e., filter-feeders, fine sediment collectors, predators, and parasites). We selected the Coleoptera assemblage to represent the macroinvertebrate community in an evaluation of the extent to which man-made wetlands in different age classes (<3 y and ≥10 y) were similar to natural wetlands (>50 y). No significant differences in Coleoptera assemblages were found between natural wetlands and man-made wetlands ≥10 y. However, man-made wetlands ≥10 y had significantly higher coleopteran species richness than natural and man-made wetlands <3 y because of the convergence of pioneering species persisting from early successional stages with representative specialized taxa from natural wetlands. Our results suggest that 10 y may be sufficient time for the macrofaunal communities of man-made wetlands to resemble those of natural wetlands.

Crustacean assemblages of coastal wetlands from fragmented and scarcely isolated islands compared with the mainland

The present study compared crustacean assemblages from coastal wetlands between a fragment archipelago and a landmass. The study included four typical crustacean taxonomic groups (i.e. Cladocera, Copepoda, Ostracoda and Malacostraca) from the Balearic Archipelago region as an example of a fragment island (‘Archipelago’) and the Catalonia region as the landmass (‘Mainland’; Spanish Mediterranean coast). We tested null hypotheses based on the expected similarity between Archipelago and Mainland in terms of crustacean assemblages and biodiversity. Similar relationships of those community attributes with environmental variables were also expected in both regions. The results partially met the null hypotheses. We found that crustacean taxonomic composition varied between Archipelago and Mainland, likely due to peculiar biological and biogeographical processes acting in the Archipelago. The relationship between crustacean assemblages and the environmental variables was mostly similar between Archipelago and Mainland, as expected. Both regions also showed similar patterns of species distribution (i.e. Archipelago and Mainland coastal wetlands were characterised by a few dominant species). This result could be masked by the ‘filter’ effect exercised by the harsh conditions of coastal wetlands. Moreover, the total diversity values (gamma biodiversity) in the Archipelago were similar to the values for the Mainland, supporting the hypothesis that fragment islands can be of substantial value for the conservation of global biodiversity.