Differential effects of biological invasions on coastal blue carbon: A global review and meta‐analysis

Human‐caused shifts in carbon (C) cycling and biotic exchange are defining characteristics of the Anthropocene. In marine systems, saltmarsh, seagrass, and mangrove habitats—collectively known as “blue carbon” and coastal vegetated habitats (CVHs) —are a leading sequester of global C and increasingly impacted by exotic species invasions. There is growing interest in the effect of invasion by a diverse pool of exotic species on C storage and the implications for ecosystem‐based management of these systems. In a global meta‐analysis, we synthesized data from 104 papers that provided 345 comparisons of habitat‐level response (plant and soil C storage) from paired invaded and uninvaded sites. We found an overall net effect of significantly higher C pools in invaded CVHs amounting to 40% (±16%) higher C storage than uninvaded habitat, but effects differed among types of invaders. Elevated C storage was driven by blue C‐forming plant invaders (saltmarsh grasses, seagrasses, and mangrove trees) that intensify biomass per unit area, extend and elevate coastal wetlands, and convert coastal mudflats into C‐rich vegetated habitat. Introduced animal and structurally distinct primary producers had significant negative effects on C pools, driven by herbivory, trampling, and native species displacement. The role of invasion manifested differently among habitat types, with significant C storage increases in saltmarshes, decreases in seagrass, and no significant effect in mangroves. There were also counter‐directional effects by the same species in different systems or locations, which underscores the importance of combining data mining with analyses of mean effect sizes in meta‐analyses. Our study provides a quantitative basis for understanding differential effects of invasion on blue C habitats and will inform conservation strategies that need to balance management decisions involving invasion, C storage, and a range of other marine biodiversity and habitat functions in these coastal systems

Specific niche requirements underpin multidecadal range edge stability, but may introduce barriers for climate change adaptation

Aim: To investigate some of the environmental variables underpinning the past and present distribution of an ecosystem engineer near its poleward range edge. Location: >500 locations spanning >7,400 km around Ireland. Methods: We collated past and present distribution records on a known climate change indicator, the reef-forming worm Sabellaria alveolata (Linnaeus, 1767) in a biogeographic boundary region over 182 years (1836–2018). This included repeat sampling of 60 locations in the cooler 1950s and again in the warmer 2000s and 2010s. Using species distribution modelling, we identified some of the environmental drivers that likely underpin S. alveolata distribution towards the leading edge of its biogeographical range in Ireland. Results: Through plotting 981 records of presence and absence, we revealed a discontinuous distribution with discretely bounded sub-populations, and edges that coincide with the locations of tidal fronts. Repeat surveys of 60 locations across three time periods showed evidence of population increases, declines, local extirpation and recolonization events within the range, but no evidence of extensions beyond the previously identified distribution limits, despite decades of warming. At a regional scale, populations were relatively stable through time, but local populations in the cold Irish Sea appear highly dynamic and vulnerable to local extirpation risk. Contemporary distribution data (2013–2018) computed with modelled environmental data identified specific niche requirements which can explain the many distribution gaps, namely wave height, tidal amplitude, stratification index, then substrate type. Main conclusions: In the face of climate warming, such specific niche requirements can create environmental barriers that may prevent species from extending beyond their leading edges. These boundaries may limit a species’ capacity to redistribute in response to global environmental change

Oregon Ballast Water Task Force Report on Ballast Water Management in Oregon

This report provides information and analysis on the current ballast water regulations at international, federal, regional and state levels; ballast water discharge trends in Oregon; the shipping industry’s compliance with Oregon law; and current and emerging issues affecting Oregon’s ballast water legislation. The report also provides recommendations for strengthening Oregon’s management of shipping-related pathways of invasive species introduction

Data from: Propagule pressure and the invasibility of marine habitats

The number of <i>Botrylloides violaceus</i> larvae settling on experimental plates 24 hours and 56 days after larval dosing. Bare space on occupied community plates at the start of the experiment, analyzed using ImageJ

Methods for: Propagule pressure and the invasibility of marin habitats

We used 15 x 15 x 1 cm PVC benthic fouling plates in a factorial experiment to test how habitat type (fixed, two levels: floating docks and benthic rock), resource availability (fixed, two levels: occupied and unoccupied PVC fouling plates), and dose-size (fixed, four levels: 0, 5, 25 and 50 larvae 225 cm^-2) affected invasion success. This yielded sixteen experimental treatments and eighty experimental units (n=5, of all possible combinations)

Phenotypic and reproductive trade-offs of colonial invertebrates to salinity

Extreme or seasonal climatic events can lead to abrupt changes in environmental conditions. These events can produce a range of phenotypic responses that may help to protect local-scale populations against changes in climate. However, empirical studies relating dramatic shifts in environmental conditions with reproductive variation in traits are rare. We performed laboratory experiments under varying episodic and chronic salinity regimes using the botryllid ascidians, Botrylloides nigrum and Botryllus planus. Our study illustrates trait variation, indicative of an adaptive plastic response to salinity and species-specific differences in salinity tolerances. Forty and twenty percent of B. nigrum and B. planus colonies exhibited a distinct physical behavior when exposed to low salinity treatments. They distended their cloacal cavities, showing their pharyngeal baskets and neural glands. Salinity negatively affected reproduction, heart rates and survival in both B. nigrum and B. planus, with speciesspecific recovery that suggests a trade-off between reproduction and recovery from environmental stress. Our study revealed that continued reproduction may delay recovery of colonies during periods of osmotic stress as their physiology may be working harder to maintain normal metabolic functions. These results suggest these species can directly respond to fine-scale environmental processes such as those associated with adaptive plasticity that may aid their persistence in a future where flood events are likely to be more common and acute

Data from: Exploring potential establishment of marine rafting species after transoceanic long-distance dispersal

Aim On March 11, 2011, the Great East Japan Earthquake triggered a massive tsunami that resulted in the largest known rafting event in recorded history. By spring 2012, marine debris began washing ashore along the Pacific Coast of the U.S. and Canada with a wide-range of Asian coastal species attached. We used this unique dataset, where the source region, date of dislodgment, and landing location are known, to assess the potential for species invasions by transoceanic rafting on marine debris. Location Northeast Pacific from 20 to 60°N Time period Current Major taxa studied Forty-eight invertebrate and algal species recorded on Japanese tsunami marine debris. Methods We developed Maximum Entropy (MaxEnt) species distribution models for 48 species recorded on Japanese tsunami marine debris to predict establishment potential along the Pacific Coast from 20-60°N. Models were compared within the context of historical marine introductions from Japan to this region to validate the emergence of marine debris as a novel vector for species transfer. Results Overall, 27% (13 species) landed with debris at locations with suitable environmental conditions for establishment and survival, indicating that these species may be able to establish new populations or introduce greater genetic diversity to already established non-native populations. A further 22 species have environmental match in areas where tsunami debris likely landed, but was not extensively sampled. Nearly 100 Japanese marine species previously invaded the northeastern Pacific, demonstrating this region's environmental suitability for rafting Japanese biota. Historical invasions from Asia are highest in California and largely known from bays and harbors. Main conclusions Marine debris is a novel and growing vector for non-native species introduction. By utilizing a unique dataset of Japanese tsunami marine debris species, our predictive models show capacity for new transoceanic invasions and can focus monitoring priorities to detect successful long-distance dispersal across the world’s oceans

A broad-scale long-term dataset of Sabellaria alveolata distribution and abundance curated through the REEHAB (REEf HABitat) Project

Numerous reef-forming species have declined dramatically in the last century, many of which have been insufficiently documented due to anecdotal or hard-to-access information. One of them, the honeycomb worm Sabellaria alveolata (L.) is a tube-building polychaete that can form large reefs, providing important ecosystem services such as coastal protection and habitat provision. It ranges from Scotland to Morocco, yet little is known about its distribution outside of the United Kingdom, where it is protected and where there is a strong heritage of natural history and sustained observations. As a result, online marine biodiversity information systems currently contain haphazardly distributed records of S. alveolata. One of the objectives of the REEHAB project (http://www.honeycombworms.org) was to combine historical records with contemporary data to document changes in the distribution and abundance of S. alveolata. Here we publish the result of the curation of 331 sources, gathered from literature, targeted surveys, local conservation reports, museum specimens, personal communications by authors and by their research teams, national biodiversity information systems (i.e. the UK National Biodiversity Network (NBN), https://nbn.org.uk/) and validated citizen science observations (i.e. https://www.inaturalist.org/). 80% of these records were not previously referenced in any online information system. Additionally, historic field notebooks from Edouard Fischer-Piette and Gustave Gilson were scanned for S. alveolata information and manually entered. Each of the 21512 S. alveolata records were checked for spatial and taxonomic accuracy, particularly in the English Channel and the North Sea where incorrectly identified observations of intertidal Sabellaria spinulosa were recorded. A further 54 observations are recorded as &lsquo;Sabellaria spp.&rsquo; as the available information did not allow for an identification to species level. Many sources reported abundances based on the semi-quantitative SACFOR scale whilst others simply noted its presence, and others still verified both its absence and presence. The result is a curated and comprehensive dataset spanning over two centuries on the past and present global distribution and abundance of S. alveolata. Sabellaria alveolata records projected onto a 50km grid. When SACFOR scale abundance scores were given to occurrence records, the highest abundance value per grid cell was retained.</span

Specific niche requirements underpin multidecadal range edge stability, but may introduce barriers for climate change adaptation

Aim To investigate some of the environmental variables underpinning the past and present distribution of an ecosystem engineer near its poleward range edge. Location >500 locations spanning >7,400 km around Ireland. Methods We collated past and present distribution records on a known climate change indicator, the reef‐forming worm Sabellaria alveolata (Linnaeus, 1767) in a biogeographic boundary region over 182 years (1836–2018). This included repeat sampling of 60 locations in the cooler 1950s and again in the warmer 2000s and 2010s. Using species distribution modelling, we identified some of the environmental drivers that likely underpin S. alveolata distribution towards the leading edge of its biogeographical range in Ireland. Results Through plotting 981 records of presence and absence, we revealed a discontinuous distribution with discretely bounded sub‐populations, and edges that coincide with the locations of tidal fronts. Repeat surveys of 60 locations across three time periods showed evidence of population increases, declines, local extirpation and recolonization events within the range, but no evidence of extensions beyond the previously identified distribution limits, despite decades of warming. At a regional scale, populations were relatively stable through time, but local populations in the cold Irish Sea appear highly dynamic and vulnerable to local extirpation risk. Contemporary distribution data (2013–2018) computed with modelled environmental data identified specific niche requirements which can explain the many distribution gaps, namely wave height, tidal amplitude, stratification index, then substrate type. Main conclusions In the face of climate warming, such specific niche requirements can create environmental barriers that may prevent species from extending beyond their leading edges. These boundaries may limit a species’ capacity to redistribute in response to global environmental change