Species composition and abundance of free-living turbellarians in three different wetlands in Southern Brazil.

Free-living turbellarians mostly live in marine and freshwater environments, but they have been little considered in ecological studies. The coastal plain in southern Brazil harbors a diverse fauna and flora, but only a few studies have related environmental factors to the abundance, richness, and distribution of turbellarians. Hence, we analyzed the structure of turbellarian communities in floating vegetation in three differently sized limnic environments. We aimed to determine differences in abundance, density, and richness of turbellarians among these habitats in relation to environmental factors. We found 1,225 turbellarians (34 species) distributed among 6 taxa. The most abundant was Tricladida with 49.4% relative abundance; the remaining (Catenulida, Dalytyphloplanida, Macrostomorpha, Kalyptorhynchia, and Prorhynchida) were less abundant. We found no significant differences among population parameters and environments. Small shallow lakes are a potentially rich environment, while water channels are the richest environment. Larger shallow lakes are not very diverse for turbellarians. Similarities regarding turbellarian communities among close limnic systems could be explained by the connectivity of bodies of water that presents similar aquatic macrophytes and hydrological subsystems, while larger shallow lakes have a different community because they have their own contributing basin and could be influenced by other factors.

Plasticity of growth rates and sizes at sexual maturity in different populations of the fiddler crab Minuca vocator (Herbst, 1804) within the same latitudinal range.

The growth rates and size at maturity of decapod crustaceans usually vary throughout latitudes. Here, we evaluated whether these life history traits can be stable within the same latitude range, where some environmental factors are constant, especially temperature. To this end, we estimated and compared the growth rates and size at sexual maturity of three populations of the fiddler crab Minuca vocator, located at latitude 23° S, in mangroves of the subtropical Brazilian coast. Variations in the growth rate of the abdominal width of females and of the propodus of the major cheliped of males were assessed by the allometric technique. The abdomen growth rates of females and the cheliped growth rates of males varied among the three populations, resulting in different sizes at maturity. These results do not support our prediction that growth rates and size at sexual maturity would remain stable in populations of the same latitude range. The differences in these life history traits could be a consequence of contrasting local conditions among mangroves. Therefore, we suggest that these crabs show plasticity and responsiveness to local-scale environmental variations, to optimize the energy allocation for maintenance, reproduction, and somatic growth.

Biodiversity of Coreoidea and Pentatomidae (Heteroptera) from Atlantic forest protected areas. Insights into their conservation

ABSTRACT Although the majority of threatened species are likely to be tropical insects, knowledge of the diversity, ecological role and impact of insect biodiversity loss on ecosystem processes is very limited. Specimens belonging to four families of Heteroptera: Pentatomidae, Coreidae, Alydidae and Rhopalidae, were collected from a protected area in the Paraná Forest, the largest ecoregion of the Atlantic Forest, in Argentina. The assemblages were characterized and the biodiversity estimated, and they were compared with the assemblages found in five other protected areas in the Brazilian Atlantic Forest. In our study area, Pentatomidae had the greatest richness and diversity; Coreidae was the second most diverse family, with highest sampling deficit, highest percentage of singletons, and lowest inventory completeness; and Rhopalidae was the best sampled family with asymptotic rarefaction curves. We explored the application of the Species Conservation Importance index, following four criteria, to evaluate the relative importance of the pentatomid species studied and its usefulness for assigning conservation values to areas. We found similar Site Conservation Values among the six areas and noted that the use of criteria was limited by the lack of information, being crucial to increase the knowledge of most of the species.

Dynamics of energy reserves and the cost of reproduction in female and male fiddler crabs.

The physiological costs of reproduction can be measured as the energy allocated to reproductive activities. In fiddler crabs, females allocate energy to vitellogenesis and brooding, whereas males perform expensive courtship behaviors. We evaluated in a large-scale study the reproduction cost of females and males of Leptuca uruguayensis in a temperate estuary, where their reproductive efforts are synchronized in a short reproductive season. The reproductive investments (vitellogenesis, spermatophore production, and male reproductive behaviors) were measured and related to the dynamics of storage and expenditure of energy reserves (glycogen, total lipids, and total protein) in the hepatopancreas, ovary, and muscle of the enlarged cheliped, throughout one annual cycle. Maximum energy storage occurred in winter, a period of low activity, whereas minimum energy storage occurred during the reproductive period, characterized by expensive activities. The glycogen reserves of the hepatopancreas decreased about 66% in females and 61% in males, suggesting high and similar physiological costs of reproduction between sexes, despite their different reproductive strategies to maximize their fitness.

Biodiversity of Coreoidea and Pentatomidae (Heteroptera) from Atlantic forest protected areas. Insights into their conservation.

Although the majority of threatened species are likely to be tropical insects, knowledge of the diversity, ecological role and impact of insect biodiversity loss on ecosystem processes is very limited. Specimens belonging to four families of Heteroptera: Pentatomidae, Coreidae, Alydidae and Rhopalidae, were collected from a protected area in the Paraná Forest, the largest ecoregion of the Atlantic Forest, in Argentina. The assemblages were characterized and the biodiversity estimated, and they were compared with the assemblages found in five other protected areas in the Brazilian Atlantic Forest. In our study area, Pentatomidae had the greatest richness and diversity; Coreidae was the second most diverse family, with highest sampling deficit, highest percentage of singletons, and lowest inventory completeness; and Rhopalidae was the best sampled family with asymptotic rarefaction curves. We explored the application of the Species Conservation Importance index, following four criteria, to evaluate the relative importance of the pentatomid species studied and its usefulness for assigning conservation values to areas. We found similar Site Conservation Values among the six areas and noted that the use of criteria was limited by the lack of information, being crucial to increase the knowledge of most of the species.

Diversity and distribution of epiphytic bromeliads in a Brazilian subtropical mangrove

ABSTRACT It is not unusual to find epiphytic bromeliads in mangroves, but most studies on mangrove vegetation do not record their presence. This study aimed to evaluate the diversity and distribution of epiphytic bromeliads in a subtropical mangrove. The richness, abundance and life form (atmospheric and tank) of bromeliads were recorded and compared among host tree species and waterline proximity. The effects of diameter and height of host trees on the abundance of bromeliads were also assessed. The mangrove was composed of Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. We recorded seven bromeliad species of the genera Tillandsia and Vriesea. The waterline proximity did not affect the abundance or diversity of bromeliads, but atmospheric forms were predominant near the waterline, whereas tank bromeliads were more frequent in the interior of the mangrove. The three mangrove species hosted bromeliads, but L. racemosa was the preferred host. The species composition showed that the distribution of bromeliads is more related to the host species than to the distance from the waterline. Bromeliad abundance increased with tree size. Bromeliads can be biological indicators of ecosystem health; therefore, inventories and host tree preferences are necessary knowledge for an adequate management of sensitive ecosystems as mangroves.

Diversity and distribution of epiphytic bromeliads in a Brazilian subtropical mangrove.

It is not unusual to find epiphytic bromeliads in mangroves, but most studies on mangrove vegetation do not record their presence. This study aimed to evaluate the diversity and distribution of epiphytic bromeliads in a subtropical mangrove. The richness, abundance and life form (atmospheric and tank) of bromeliads were recorded and compared among host tree species and waterline proximity. The effects of diameter and height of host trees on the abundance of bromeliads were also assessed. The mangrove was composed of Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. We recorded seven bromeliad species of the genera Tillandsia and Vriesea. The waterline proximity did not affect the abundance or diversity of bromeliads, but atmospheric forms were predominant near the waterline, whereas tank bromeliads were more frequent in the interior of the mangrove. The three mangrove species hosted bromeliads, but L. racemosa was the preferred host. The species composition showed that the distribution of bromeliads is more related to the host species than to the distance from the waterline. Bromeliad abundance increased with tree size. Bromeliads can be biological indicators of ecosystem health; therefore, inventories and host tree preferences are necessary knowledge for an adequate management of sensitive ecosystems as mangroves.

Land planarian assemblages in protected areas of the interior atlantic forest: implications for conservation.

Land planarians are an interesting group of free-living flatworms that can be useful as bioindicators because of their high sensitivity to environmental changes and low dispersal capacity. In this study, we describe and compare assemblages of land planarians from areas with different conservation degrees of the Interior Atlantic Forest (Misiones, Argentina), and assess factors that could be related to their abundance and richness. Eight sites were tracked in search of land planarians in Reserva de Vida Silvestre Urugua-í (RVSU) and Campo Anexo Manuel Belgrano (CAMB). Diurnal and nocturnal surveys were performed in each site along nine sampling campaigns. We collected 237 individuals belonging to 18 species of the subfamily Geoplaninae. All sites were dominated by Geoplana sp. 1 and Pasipha hauseri. The richness estimators showed that there would be more species in RVSU than in CAMB. The abundance and richness of land planarians was high during the night and after rainfalls, suggesting an increased activity of flatworms under such conditions. The abundance and richness of land planarians were also related to the conservation condition of the sites. Disturbed sites showed less abundance and richness, and were segregated from non-disturbed ones by nmMDS analysis. Beta diversity between sites was higher than expected, indicating that the species turnover between sites contributed more to the total richness (gamma diversity) than the alpha diversity.