No abstract

Deforestation results in habitat fragmentation, decreasing diversity, and functional degradation. For mangroves, no data are available on the impact of deforestation on the diversity and functionality of the specialized invertebrate fauna, critical for their functioning. We compiled a global dataset of mangrove invertebrate fauna comprising 364 species from 16 locations, classified into 64 functional entities (FEs). For each location, we calculated taxonomic distinctness (Δ+), functional richness (FRi), functional redundancy (FRe), and functional vulnerability (FVu) to assess functional integrity. Δ+ and FRi were significantly related to air temperature but not to geomorphic characteristics, mirroring the global biodiversity anomaly of mangrove trees. Neither of those two indices was linked to forest area, but both sharply decreased in human-impacted mangroves. About 60% of the locations showed an average FRe < 2, indicating that most of the FEs comprised one species only. Notable exceptions were the Eastern Indian Ocean and west Pacific Ocean locations, but also in this region, 57% of the FEs had no redundancy, placing mangroves among the most vulnerable ecosystems on the planet. Our study shows that despite low redundancy, even small mangrove patches host truly multifunctional faunal assemblages, ultimately underpinning their services. However, our analyses also suggest that even a modest local loss of invertebrate diversity could have significant negative consequences for many mangroves and cascading effects for adjacent ecosystems. This pattern of faunal-mediated ecosystem functionality is crucial for assessing the vulnerability of mangrove forests to anthropogenic impact and provides an approach to planning their effective conservation and restoration.

No abstract

No abstract

The abundance and sexual maturity of piangua Anadara similis in La Plata Archipelago, Bahía Málaga, Pacific coast of Colombia, was analyzed between September 2009 and August 2010. Sexual maturity of these organisms was studied at macroscopic level using fresh samples and at microscopic level using standard histological techniques. The mean density was estimated in 0.130 ± 0.098 ind/m2 and the mean size was 42.30 ± 5.00 mm. Months with the presence of the highest densities of piangua were May (0.295 ind/m2) and August (0.195 ind/m2). The mean sexual maturity size was estimated in 41.8 ± 4.5 mm, while the size at which at least 50% of the population of A. similis have had its first spawn was estimated in 41 mm. Reproductive activity of the species was present year-round with higher peaks in March (83.33%) and April (75.00%). 4.30% of organisms analyzed showed signs of hermaphroditism, being this the first record of this kind for the species. Higher density, larger mean size, higher meat yield in females as well as the presence of more female reproductive tissue, suggest a process of sexual reversion in the species, which have to be further studied. Low capture and sexual maturity sizes, as well as the low density of organisms found during the present work, might be the product of high fishery pressure, habitat modifications, and pollution processes in the area, factors that have to be studied in detail in order to implement management strategies for the species.

No abstract

No abstract

No abstract