Diversity of tropical macroalgae in the New Zealand marine aquarium trade

<p>Exotic species often slip through international borders undetected. Many perish but for some species introduction to a foreign land or sea brings release from natural enemies and a chance to establish a population. Increased global trade has increased the frequency of species introductions through stowaways and lapses in biosecurity. Once an invader is established there is the opportunity for explosive population growth at the detriment of native species and humans. The marine aquarium trade is a significant vector of species introductions, including algal introductions. The most publicized introduction from aquaria was the release of the green alga Caulerpa taxifolia from the Oceanographic Museum in Monaco. C. taxifolia introduction had large negative impacts on the invaded ecosystem. Molecular barcoding of tropical macroalgae entering the New Zealand aquarium trade was implemented using various molecular markers (cox1, cox3, rbcL tufA, LSU). Both NCBI Blast searches and maximum-likelihood phylogenies were used to identify the isolates. A total of 62 species of tropical macroalgae were identified from coral rocks imported into New Zealand, plus samples from reef hobbyists. Some species found are known as invasive elsewhere, for example, Caulerpa cylindracea, C. racemosa, C. sertularioides, Ulva ohnoi and Chaetomorpha vieillardii. All three major groups of algae were well represented in my findings with 26 species of red algae, 24 species of green algae and 12 species of brown algae. Temperature tolerance limits are the largest determinant in survival in algae, while salinity and pH are less significant. Temperature tolerance of tropical algae to the minimum Sea Surface Temperature in Auckland (14°C) and Wellington (11°C) was tested. My results show that one species Chaetomorpha vieillardii can survive at Auckland minimum winter sea surface temperatures. Our findings have important implications for New Zealand biosecurity, as not only are a large diversity of exotic macroalgae entering the New Zealand marine aquarium trade unregulated, but there is also the potential for them to survive in New Zealand waters. </p>

Diversity of tropical macroalgae in the New Zealand marine aquarium trade

<p>Exotic species often slip through international borders undetected. Many perish but for some species introduction to a foreign land or sea brings release from natural enemies and a chance to establish a population. Increased global trade has increased the frequency of species introductions through stowaways and lapses in biosecurity. Once an invader is established there is the opportunity for explosive population growth at the detriment of native species and humans. The marine aquarium trade is a significant vector of species introductions, including algal introductions. The most publicized introduction from aquaria was the release of the green alga Caulerpa taxifolia from the Oceanographic Museum in Monaco. C. taxifolia introduction had large negative impacts on the invaded ecosystem. Molecular barcoding of tropical macroalgae entering the New Zealand aquarium trade was implemented using various molecular markers (cox1, cox3, rbcL tufA, LSU). Both NCBI Blast searches and maximum-likelihood phylogenies were used to identify the isolates. A total of 62 species of tropical macroalgae were identified from coral rocks imported into New Zealand, plus samples from reef hobbyists. Some species found are known as invasive elsewhere, for example, Caulerpa cylindracea, C. racemosa, C. sertularioides, Ulva ohnoi and Chaetomorpha vieillardii. All three major groups of algae were well represented in my findings with 26 species of red algae, 24 species of green algae and 12 species of brown algae. Temperature tolerance limits are the largest determinant in survival in algae, while salinity and pH are less significant. Temperature tolerance of tropical algae to the minimum Sea Surface Temperature in Auckland (14°C) and Wellington (11°C) was tested. My results show that one species Chaetomorpha vieillardii can survive at Auckland minimum winter sea surface temperatures. Our findings have important implications for New Zealand biosecurity, as not only are a large diversity of exotic macroalgae entering the New Zealand marine aquarium trade unregulated, but there is also the potential for them to survive in New Zealand waters. </p>

The global spread and invasion capacities of alien ants

The ecological and economic impacts of biological invasions are usually highly conspicuous, but these are the outcome of a global, multistage process that is obscured from view. For most taxa, we lack a large-scale picture of the movements of alien species, the biases and filters that promote or inhibit their spread at each stage, and blind spots in our ability to detect species during their spread. For instance, countries rely heavily on customs interceptions to prevent new species introductions, but their efficacy for detecting invaders remains unclear. To address these gaps, we synthesize and provide data at unprecedented geographic resolution on the global diversity and distribution of alien ants, a pervasive group strongly impacting humans and ecosystems. From >145,000 records spanning 602 regions, we identify 522 ant species exhibiting human-mediated spread, doubling recent estimates of their diversity. We show that movements of alien ant species across regions globally are non-random and, moreover, that these flows differ by the extents to which species invade—ranging from arrival to indoor establishment, naturalization, and harmful status. Importantly, we find that almost two-thirds of the 309 species that naturalize globally—most of which are ground- and litter-dwelling—are absent from customs interceptions, which record disproportionately high numbers of arboreal species. Our results illustrate the vast, yet uneven extent of ant invasions globally, and suggest that most alien species bypass biosecurity controls while spreading successfully worldwide. This raises doubts on the efficacy of current customs interceptions procedures and highlights a need for radically new approaches.

Natural history collections recapitulate 200 years of faunal change

Changing species assemblages represent major challenges to ecosystems around the world. Retracing these changes is limited by our knowledge of past biodiversity. Natural history collections represent archives of biodiversity and are therefore an unparalleled source to study biodiversity changes. In the present study, we tested the value of natural history collections for reconstructing changes in the abundance and presence of species over time. In total, we scrutinized 17 080 quality-checked records for 242 epibenthic invertebrate species from the North and Baltic Seas collected throughout the last 200 years. Our approaches identified eight previously reported species introductions, 10 range expansions, six of which are new to science, as well as the long-term decline of 51 marine invertebrate species. The cross-validation of our results with published accounts of endangered species and neozoa of the area confirmed the results for two of the approaches for 49 to 55% of the identified species, and contradicted our results for 9 to 10%. The results based on relative record trends were less validated. We conclude that, with the proper approaches, natural history collections are an unmatched resource for recovering early species introductions and declines.

Introduction bias: Imbalance in species introductions may obscure the identification of traits associated with invasiveness

The introduction stage is usually overlooked in trait-based studies of invasiveness, implicitly assuming that species introductions are random. However, human activities promote the movement of specific types of species. Thus, species deliberately introduced for distinct purposes (e.g. gardening, forestry) or as contaminants of human commodities (e.g. stowaway) will likely show particular traits. If species with certain traits have been preferentially introduced (i.e. introduction bias), some traits may have been mistakenly linked to species' invasion abilities due to their influence on introduction probability. In this work, we propose a theoretical framework with different scenarios of introduction bias. The introduction scenarios are: (1) Random introduction, independent from traits; (2) Biologically biased introduction, following the worldwide distribution of the trait; and (3) Human biased introduction, following a theoretical introduction pathway that favours the introduction of species with high values of the trait. We evaluate how the introduced trait distributions in these scenarios may affect trait distributions in naturalized and invasive species pools under different hypothesized associations between traits and the probabilities of naturalization and invasion. The aim of this work is to identify situations where ignoring introduction bias may lead to spurious correlations being found between species' traits and species' ability to become naturalized or invasive. Our framework strongly points to the need to evaluate the traits of species that have become naturalized or invasive along with the traits of species that have failed to do so in order to unravel any existing introduction bias that may confound the correlation between species' traits and invasion success. Overlooking a possible introduction bias may lead to the overestimation of the correlation between the trait and the species' invasion ability, especially in cases when the pool of introduced species shows extreme values of the trait distribution (as compared to a random introduction). Trait-based studies that deserve special attention to avoid undesired effects of introduction bias on their findings are: those that investigate naturalization using only the pool of naturalized species, and those studies that examine invasiveness by comparing invasive species with native species.

Invasive alien species in changing marine arctic economies and ecosystems.

The rate of change in Arctic marine environments in response to shifts driven by climate change threatens Arctic resilience. The growing recognition and visibility of these changes have scientific and social roots. Mitigating these consequences is therefore a social-scientific concern. Multiple scales, perspectives, and governance systems for Arctic marine environments, alongside receding climate and economic barriers to species movements and scientific research, create challenges and opportunities that differ in magnitude and breadth from marine invasions elsewhere. The receding barriers in the marine Arctic amplify the potential ecological and economic consequences from new species introductions and range expansions from adjacent biomes. While there is consensus that marine invasive species can cause severe damages to ecosystems and resource-dependent communities, which species pose what threats, and to whom, remain complex dynamic socioecological and biogeophysical economic questions. Decisions over prevention, detection, and monitoring along with institutional frameworks for cooperating and responding to threats also affect the expected severity of impacts. Technologies, and costs, for identifying and monitoring species compositions and risks are evolving, with novel research advances as well as increasingly sophisticated ecological-economic, environmental niche, and habitat suitability models. Despite advances in understanding drivers and dynamics of new species introductions, a dearth of baseline knowledge regarding Arctic marine invasions remains. Potential consequences extend beyond ecosystem changes and include legal, institutional, and social shifts. Studies on the red king and snow crab invasions in the Barents Sea from multiple disciplinary angles showcase complex social, economic, and ecological interconnections that are transforming communities and ecosystems.