Management of alien aquatic invasive species: Strategic guidelines and policy in India

The present article is aimed at understanding current policies and implementation strategies for the management of aquatic invasive species in India and identifying opportunities for improvement. Existing management approaches and policies have briefly been put into place concerning fish introductions and aquatic invasive species, but looking at their effectiveness, it is argued that mitigating the negative impacts caused by invasive species should be at the core for their successful management. International institutions have explicitly recognized the need to contain and eradicate biological invasions and have set of relevant guidelines and enforcements. In India, risk assessment, risk management, quarantine, biosecurity and regulatory mechanisms have been developed and implemented to filter fish introductions and consequently check aquatic invasions. Nevertheless, invasive species introduced into the inland waters are emerging as ‘chronic risks’ to the aquatic biodiversity and ecosystem services. It is imperative that these emerging issues are put on the National Agenda and Action Plan to regulate fish invasions and minimise their adverse impacts. A National Policy on prevention and control of aquatic invasive species is urgently needed to deal with nuisance and harmful impacts. Some future needs have also been suggested to tackle this issue.

Erythropodium caribaeorum (Duchassaing and Michelotti, 1860) (Cnidaria: Alcyonacea), an additional alien coral in the Southwestern Atlantic

Invasive species may compromise biodiversity and ecosystem services, and represent a steadily growing concern for coastal marine ecosystems. The marine aquarium trade (MAT) is the source of some of the world’s worst aquatic invasions, inflicting multimillion-dollar losses in infected regions. In the Southwestern Atlantic (SWA), two Indo-Pacific coral species were recently introduced as a result of the MAT and already dominate the substrate at the introduction site in Southeastern Brazil (Praia Vermelha, Angra dos Reis, Rio de Janeiro State). Herein, based on morphological and molecular evidence, we report a Caribbean native coral species likely introduced by the MAT in Praia Vermelha, Erythropodium caribaeorum (Duchassaing & Michelotti 1860). While the eradication of coral species that already have a pest status in the SWA is unlikely, we propose that the eradication of the three species still contained to their introduction sites, including E. caribaeorum, is still feasible and depends on a rapid and integrated embracement of the task by core stakeholders. Priority actions for the regulation of MAT and hobbyism in Brazil are proposed.

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

<i>Abstract.</i>—Lakes, like islands, have been model systems for testing important concepts in landscape ecology. Lake assemblage and community composition, generally, and the occurrence of invaders, specifically, are controlled by a range of factors across scales. Here, I use the example of Rainbow Smelt <i>Osmerus mordax </i>invasions in inland lakes to illustrate common problems in both predictive and explanatory models of invasive species distributions across landscapes. Using variables related to dispersal and regional- and lake-scale environment, I fitted a series of boosted regression tree models to examine the factors that explain Rainbow Smelt invasion success. These models illustrate the potential effects of extrapolation and nonequilibrium conditions, the role of human activities, and the difficulty of understanding the importance of biotic interactions in the spread of invasives. Understanding the factors controlling invasions should inform management and conservation of inland lake ecosystems. For this to be effective, a mechanistic framework is needed to untie correlations in potential driving factors. Emerging data sets with fine spatial grain and broad spatial extent will support the transition from correlative models to mechanistic understanding of aquatic invasions.

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

<i>Abstract.</i>—Species distribution models are important tools for conservation and management of aquatic ecosystems. In this study, nine fish species (Caspian Lamprey <i>Caspiomyzon wagneri</i>, <i>Acanthalburnus urmianus</i>, <i>Alburnoides namaki</i>, <i>Capoeta buhsei</i>, Mangar <i>Luciobarbus esocinus </i>[also known as <i>Barbus esocinus</i>], <i>Luciobarbus xanthopterus</i>, <i>Mesopotamichthys sharpeyi</i>, <i>Glyptothorax silviae</i>, and <i>Iranocichla hormuzensis</i>) that are sensitive to habitat changes induced by human activities were predicted by species distribution models throughout rivers in Iran. The fish data used cover several time periods (1970–2000) obtained from databases originating from field sampling, several museums, and the literature. We considered seven environmental variables, including channel slope, bank-full width, wetted width, elevation, mean air temperature, range of air temperature, and annual precipitation to model distributions of all nine species using an ensemble forecasting approach. Models used included generalized linear models, generalized additive models, classification tree analysis, artificial neural networks, surface range envelopes, boosted regression trees, random forest, multivariate adaptive regression splines, and flexible discriminant analysis. Additionally, we compared known distributions of species with modeled distributions, and we used the models to identify potential habitats for the nine species outside previously sampled areas. True skill statistic for each species was, on average, greater than 0.80 (i.e., excellent). Moreover, whereas surface range envelopes for all species had the lowest performance, random forest and generalized boosting methods had the highest performance. Among species studied, Caspian Lamprey, <i>Luciobarbus xanthopterus</i>, and <i>Mesopotamichthys sharpeyi </i>were predicted only in basins where they had been previously detected. In contrast, other species (i.e., <i>Acanthalburnus urmianus</i>, <i>Alburnoides namaki</i>, <i>Capoeta buhsei</i>, Mangar, <i>Glyptothorax silviae</i>, and <i>Iranocichla hormuzensis</i>) were predicted not only in basins with previous records, but also in new basins. These results deepen our understanding of distribution patterns of the studied species in Iran and can be used to guide regional conservation planning, identify critical habitats for threatened species, and inform management and conservation of inland aquatic ecosystems. For this to be effective, a mechanistic framework is needed to untie correlations in potential driving factors. Emerging data sets with fine spatial grain and broad spatial extent will support the transition from correlative models to mechanistic understanding of aquatic invasions.