Watersipora Subtorquata Research Articles

Marine aquaculture as a source of propagules of invasive fouling species.

Non-indigenous species tend to colonize aquaculture installations, especially when they are near international ports. In addition to the local environmental hazard that colonizing non-indigenous species pose, they can also take advantage of local transport opportunities to spread elsewhere. In this study, we examined the risk of the spread of eight invasive fouling species that are found in mussel farms in southern Brazil. We used ensemble niche models based on worldwide occurrences of these species, and environmental variables (ocean temperature and salinity) to predict suitable areas for each species with three algorithms (Maxent, Random Forest, and Support Vector Machine). As a proxy for propagule pressure, we used the tonnage transported by container ships from Santa Catarina (the main mariculture region) that travel to other Brazilian ports. We found that ports in the tropical states of Pernambuco, Ceará, and Bahia received the largest tonnage, although far from Santa Catarina and in a different ecoregion. The ascidians Aplidium accarense and Didemnum perlucidum are known from Bahia, with a high risk of invasion in the other states. The bryozoan Watersipora subtorquata also has a high risk of establishment in Pernambuco, while the ascidian Botrylloides giganteus has a medium risk in Bahia. Paraná, a state in the same ecoregion as Santa Catarina is likely to be invaded by all species. A second state in this region, Rio Grande do Sul, is vulnerable to A. accarense, the barnacle Megabalanus coccopoma, and the mussel Mytilus galloprovincialis. Climate change is changing species latitudinal distributions and most species will gain rather than lose area in near future (by 2050). As an ideal habitat for fouling organisms and invasive species, aquaculture farms can increase propagule pressure and thus the probability that species will expand their distributions, especially if they are close to ports. Therefore, an integrated approach of the risks of both aquaculture and nautical transport equipment present in a region is necessary to better inform decision-making procedures aiming at the expansion or establishment of new aquaculture farms. The risk maps provided will allow authorities and regional stakeholders to prioritize areas of concern for mitigating the present and future spread of fouling species.

The Influence of Marina Characteristics on Non-native Colonisation

The marina properties, such as; salinity range, tidal fluctuations, depth, and ascidian presence in-fluence the distribution of invasive non-natives. Transport vectors, aquaculture and fishery practic-es also have an important role in the distribution of invasive non-native species during the bioinva-sion process. We focused on 10 invasive non-native species of marine invertebrates in the UK. This study explained the distribution and ecology of five invasive non-native species (Styela clava (As-cidia), Didemnum vexillum (Ascidia), Caprella mutica (Crustacea), Crepidula fornicata (Gastropo-da), Watersipora subtorquata (Bryozoa)) and the marina characteristics of five invasive non-native species colonization (Austrominius modestus (Arthropoda), Ciona intestinalis (Ascidia), Botrylloides violaceus (Ascidia), Tricellaria inopinata (Bryozoa), Bugula neritina (Bryozoa)) in Wales coasts. The study site deployed settlement tiles in the inner and the outer tile as two positions in each marina: An equal number of vertical and horizontal tiles was deployed at each site with half-sampled at two weeks (very early colonization) and at eight weeks (later colonization). The results showed that some variations in marina characteristics affected the distribution of invasive non-native species. Invasive non-native species abundance, diversity and multivariate structure of the assemblages were very high. The colonization of tiles varied between locations at the entrance and within the marina, but not in any way, and the effect of tile orientation was surprisingly low.

The effect of an invasive foundation species on diversity is due to increased habitat availability

Both foundation species and introduced species have exceptional influence on community diversity and structure, though they have historically been thought to have opposite effects. However, when introduced species can provide novel habitat within a community, their benefit to the community as a foundation species may outweigh their cost as an invader. The magnitude or direction of species interactions can depend on the environment, thus the net effect of introduced foundation species can vary across different environmental factors. A settlement tile experiment was conducted on the fouling communities of California harbors to determine whether the effects of a widespread invasive bryozoan, Watersipora subtorquata, vary between two locations in its California range, Alamitos Bay and Bodega Harbor. Treatments with live and dead colonies and two sizes of blank tiles were used to evaluate the effects of colony structure and available bare substrate on both mobile and sessile species in the community. Though mobile invertebrate communities in each location across treatments were not significantly dissimilar to each other, communities on large tiles were significantly dissimilar to other communities in each location. Mobile species richness was greatest on live colony and small tiles in Bodega, but greatest on dead colony and large tiles in Alamitos. Both the diversity and community structure of sessile invertebrates across treatments differed significantly between regions. Diversity was greatest on dead colony tiles in Alamitos, where communities were more dissimilar across treatments, but was greatest on live W. subtorquata tiles in Bodega where communities were less dissimilar across treatments. These results highlight the potential for W. subtorquata to have location-dependent net effects on the community throughout its invasive range as a foundation species.

The effect of an invasive bryozoan on community diversity and structure varies across two locations

Foundation species and invasive species strongly influence community diversity and structure, but typically in different ways. However, when widespread invasive species provide novel habitat within a community, their net effect may depend on both the environment and community composition. Fouling communities in northern and southern California harbors were surveyed to determine whether there was variation between two locations in the percent cover of an invasive bryozoan, Watersipora subtorquata (d’Orbigny, 1852), and its relationship to community diversity and composition in these two environments. Diversity significantly differed between locations and had a location-dependent association with W. subtorquata abundance. Communities were significantly dissimilar between locations, and W. subtorquata abundance had the highest percent contribution to community dissimilarity when compared to other species in the community. These results suggest that invasive species may have both facilitative and inhibitive relationships with species in a community, but that the net balance of these interactions depends on both the environmental and community context.

Settlement of non-native Watersipora subtorquata (d'Orbigny, 1852) in artificial collectors deployed in Colombo Port, Sri Lanka

Settlement of non-native Watersipora subtorquata (d'Orbigny, 1852) in artificial collectors deployed in Colombo Port, Sri Lanka

(Re)appreciating the role of life history in eco‐evolutionary dynamics

(Re)appreciating the role of life history in eco‐evolutionary dynamics

Field manipulations of resources mediate the transition from intraspecific competition to facilitation.

Population density affects individual performance, though its effects are often mixed. For sessile species, increases in population density typically reduce performance. Still, cases of positive density-dependence do occur in sessile systems and demand explanation. The stress gradient hypothesis (SGH) predicts that under stressful conditions, positive effects of facilitation may outweigh the negative effects of competition. While some elements of the SGH are well studied, its potential to explain intraspecific facilitation has received little attention. Further, there have been questions regarding whether the SGH holds if the stressor is a resource. Most studies of interactions between the environment and intraspecific facilitation have relied on natural environmental gradients; manipulative studies are much rarer. To test the effects of intraspecific density and resources, we manipulated resource availability over natural population densities for the marine bryozoan Watersipora subtorquata. We found negative effects of density on colony performance in low resource environments, but mainly positive density-dependence in high resource environments. By adding resources, competition effects were reduced and the positive effects of facilitation were revealed. Our results suggest that resource availability mediates the relative strength of competition and facilitation in our system. We also suggest that intraspecific facilitation is more common than may be appreciated and that environmental variation may mediate the balance between negative and positive density-dependence.

Fouling bryozoan fauna from Hurghada, Red Sea, Egypt. II. Encrusting species

The current work aims to present systematic information about encrusting fouling bryozoan fauna collected from Hurghada, Egyptian Red Sea. During September 2015, scraped fouling samples were collected from beneath the jetty of the National Institute of Oceanography and Fisheries, Red Sea branch, Egypt. Five species of encrusting bryozoan are recorded in the present study. These are Celleporaria aperta, Parasmittina egyptiaca, Watersipora subtorquata, Hippopodina feegeensis and Scorpiodinipora costulata, affiliating to 5 families, which belong to the suborder Neocheilostomina. Parasmittina egyptiaca, Hippopodina feegeensis and Scorpiodinipora costulata are new records from Hurghada, Red Sea waters. Descriptions of the recorded species are given with illustrative photos as well as their geographical distribution and habitats.

Dispersal duration mediates selection on offspring size

Offspring size varies at all levels of organisation, among species, mothers and clutches. This variation is thought to be the result of a tradeoff between offspring quality and quantity, where larger offspring perform better but are more costly to produce. Local environmental conditions alter the benefits of increased offspring size and thereby mediate selection on this trait. For sessile organisms, dispersal is a crucial part of the offspring phase, and in animals, bigger offspring tend to better endure longer dispersal distances than smaller offspring because they have more energy. Theory predicts that increasing distances between suitable habitats strengthens selection for larger offspring. We manipulated the dispersal duration of offspring of different sizes in the bryozoan Watersipora subtorquata and then examined the relationship between offspring size and post‐metamorphic performance in the field. We found that selection on offspring size is altered by larval experience. Larger offspring had higher post‐settlement performance if the larval period was short but, contrary to current theory, performed worse when the larval period was extended. The reversal of the relationship between offspring size and performance by extending the larval phase in Watersipora may be due to the way in which offspring size affects growth in this species. Regardless of the mechanism, it appears that experiences in one life‐history stage alter selection on offspring size in another stage, even when they occupy identical habitats as adults.

Rapid assessment of marine non-indigenous species on mooring lines of leisure craft: new records in Croatia (eastern Adriatic Sea)

Leisure-craft mooring lines were surveyed in six berthing areas along the Croatian coast during June 2014. The aim of this study was to investigate the presence of non-indigenous species (NIS) on mooring lines known as ‘lazy’ lines. Four NIS were observed during the survey: the tunicate Styela plicata, the serpulid Hydroides elegans and two bryozoans, Celleporaria brunnea, and Amathia verticillata. Three cryptogenic species were also found during the survey: the amphipod Elasmopus rapax, the barnacle Amphibalanus amphitrite, and the bryozoan Watersipora subtorquata. Styela plicata, C. brunnea, and W. subtorquata represent the first records for Croatia. Furthermore, C. brunnea and W. subtorquata are new to the whole Adriatic Sea. All NIS and cryptogenic species were recorded in Biograd na Moru. In addition, S. plicata was also recorded in Zadar. The use of ‘lazy’ lines proved to be a rapid and effective method for recording sessile species and monitoring NIS presence. This method could be undertaken for regular NIS surveys of leisure-craft berthing areas.

The Effects of Anthropogenic Structures on Habitat Connectivity and the Potential Spread of Non-Native Invertebrate Species in the Offshore Environment.

Offshore structures provide habitat that could facilitate species range expansions and the introduction of non-native species into new geographic areas. Surveys of assemblages of seven offshore oil and gas platforms in the Santa Barbara Channel revealed a change in distribution of the non-native sessile invertebrate Watersipora subtorquata, a bryozoan with a planktonic larval duration (PLD) of 24 hours or less, from one platform in 2001 to four platforms in 2013. We use a three-dimensional biophysical model to assess whether larval dispersal via currents from harbors to platforms and among platforms is a plausible mechanism to explain the change in distribution of Watersipora and to predict potential spread to other platforms in the future. Hull fouling is another possible mechanism to explain the change in distribution of Watersipora. We find that larval dispersal via currents could account for the increase in distribution of Watersipora from one to four platforms and that Watersipora is unlikely to spread from these four platforms to additional platforms through larval dispersal. Our results also suggest that larvae with PLDs of 24 hours or less released from offshore platforms can attain much greater dispersal distances than larvae with PLDs of 24 hours or less released from nearshore habitat. We hypothesize that the enhanced dispersal distance of larvae released from offshore platforms is driven by a combination of the offshore hydrodynamic environment, larval behavior, and larval release above the seafloor.

Increased larval planktonic duration and post‑recruitment competition influence survival and growth of the bryozoan Watersipora subtorquata

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 531:179-191 (2015) - DOI: https://doi.org/10.3354/meps11339 Increased larval planktonic duration and post‑recruitment competition influence survival and growth of the bryozoan Watersipora subtorquata Michael A. Sams1,2,*, Fletcher Warren-Myers1, Michael J. Keough1 1Department of Zoology, University of Melbourne, Victoria 3010, Australia 2School of Biological Sciences, University of Queensland, St. Lucia, Queensland 4067, Australia *Corresponding author: m.sams@uq.edu.au ABSTRACT: For organisms with complex life cycles, longer time spent in the plankton by dispersing propagules can cause reduced survival, growth and fecundity, which could alter interactions between neighbours in the post-dispersal environment. We compared post-settlement performance of bryozoan Watersipora subtorquata colonies that developed from larvae of different natural and experimental planktonic durations over ca. 15 wk of colony growth. Settlers were situated either near established adults of the ascidian Botrylloides leachii or without competition. Increased larval planktonic durations reduced colony growth in the absence of competition; colonies that developed from longer or delayed larval durations were 2 to 3 times smaller than those that developed from shorter durations. Colonies that developed from longer larval periods (natural or experimental) also experienced higher mortality (75 to 100%) than those that settled quickly (20 to 42%), but these effects varied between experiments and seasons. In winter, W. subtorquata colonies of longer larval planktonic durations experienced greater mortality when adjacent to established B. leachii, whereas differences in colony growth due to planktonic duration were reduced by adjacent B. leachii. The influence of B. leachii varied between experiments in different seasons, however, and did not alter colony performance in summer. Our findings demonstrate that while increased larval planktonic duration can be costly for post-dispersal growth and survival, some differences can be mediated by species interactions and environmental variability. This suggests that while connectivity among populations that take longer to disperse may be limited, it may also be influenced in complex ways by the post-recruitment environment and not simply dispersal duration. KEY WORDS: Larval dispersal · Planktonic duration · Competition · Marine bryozoan · Post-settlement · Watersipora Full text in pdf format Supplementary material 1Supplementary material 2 PreviousNextCite this article as: Sams MA, Warren-Myers F, Keough MJ (2015) Increased larval planktonic duration and post‑recruitment competition influence survival and growth of the bryozoan Watersipora subtorquata . Mar Ecol Prog Ser 531:179-191. https://doi.org/10.3354/meps11339 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 531. Online publication date: July 02, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Relative contributions of offspring quality and environmental quality to adult field performance

Determinants of adult performance, such as growth and survival, are influenced by extrinsic, environmental and intrinsic, phenotypic factors. The relative importance of extrinsic and intrinsic factors, while ecologically relevant, is rarely estimated simultaneously. We estimate the relative contributions of offspring size (intrinsic) and various environmental factors (extrinsic) on adult performance in the marine colonial bryozoan Watersipora subtorquata. We used a variance partitioning approach for both new and previously published data, enabling us to examine the performance of over 1000 individuals in the field. We found offspring size to explain relatively little variation in adult performance. Of the environmental factors taken to account, temporal variation and an environmental gradient had the strongest influences.

Trophic cascades in an invaded ecosystem: native keystone predators facilitate a dominant invader in an estuarine community

Determining how various factors contribute to the invasibility of systems is essential for both understanding community formation and informing management of natural areas. Research demonstrating that predators can provide biotic resistance to invasions by consuming invasive species has led to the presence of healthy predator populations being associated with reduced invasion potential of ecosystems. However, predators structure communities in many ways and their presence could also potentially facilitate invasions if they decrease populations of native species that compete with or consume an invader. We considered these two impacts of predators on invasion by analyzing the effects of two keystone predators (Pisaster spp. and Enhydra lutris nereis) on two foundation species (a native mussel Mytilus californianus and the invasive exotic bryozoan Watersipora subtorquata, a putative competitor for space with Mytilus californianus). Both native predators were found to facilitate the invasion of the exotic bryozoan, and the rate of invasion was highest when both predators were present. Facilitation of W. subtorquata occurred via indirect mechanisms that partly involved the removal of a competitor (mussels) via predation. These results illustrate that although predators can provide biotic resistance to invasion, healthy predator populations do not always confer this advantage and in fact may facilitate invasions. Therefore, implementation of management actions to enhance populations of top predators could also potentially increase the invasibility of some ecosystems.

The identity of the invasive fouling bryozoan Watersipora subtorquata (d'Orbigny) and some other congeneric species.

Watersipora subtorquata (d'Orbigny, 1852) has been widely reported as a fouling species from tropical to temperate waters. The continued confusion over the correct name for this species led us to provide a redescription of d'Orbigny's type of Cellepora subtorquata, and to make comparisons with other species of Watersipora. We show that the majority of specimens assigned to W. subovoidea (d'Orbigny, 1852) are morphologically distinct from the recently erected neotype of W. subovoidea; these specimens are here reidentified as Watersipora subtorquata. Other specimens previously assigned to W. subtorquata belong to W. subatra (Ortmann, 1890), described originally from Japan. Owing these inconsistences, we suggest setting aside the neotype of Watersipora subovoidea, which is based on Busk's Lepralia cucullata and is not from the same locality as d'Orbigny's type. Watersipora cucullata is redescribed and figured using Busk's specimens; the species is known from the Mediterranean, including the Adriatic. Three other species--Watersipora atrofusca (Busk, 1856), Watersipora aterrima (Ortmann, 1890) and Watersipora nigra (Canu & Bassler, 1930)--are also refigured. Watersipora edmondsoni Soule & Soule, 1975 is synonymised with W. subtorquata (d'Orbigny). Two new species are described, Watersipora mawatarii n. sp. from Japan and Watersipora souleorum n. sp. from the Azores, Cape Verde, Naples and Indian Ocean. A key is given to the Recent species of Watersipora.

Transient small boats as a long-distance coastal vector for dispersal of biofouling organisms

Alaska is at the northern end of an apparent latitudinal trend of decreasing coastal marine introductions on the West Coast of North America. Historical propagule supply may have played a role in forming this trend, but few studies have evaluated propagule supply to northern latitudes. Here, we examined the role of small boat traffic as a mechanism of long-distance spread for nonindigenous species (NIS) into coastal Alaska. We used a combination of public records, marina surveys, and boater interviews to characterize vessel traffic patterns and boater behaviors. In-water SCUBA sampling of recently arrived transient boats provided data on extent, richness, composition, and biogeography of biofouling incursions to Alaska from outside of the state. We documented a striking seasonality and directionality of vessel traffic, and most vessels were on voyages of >900 km. Most transient vessels sampled had few organisms, although one third had >100 organisms on submerged surfaces. Several NIS were recorded, including two that are not known to be established in Alaska (Watersipora subtorquata and Amphibalanus improvisus). The seasonal northward pulse of vessels and their cumulative biofouling species represent an important incursion mechanism for species yet to establish at the northern edge of a marine bioinvasion front in the northeastern Pacific. The low numbers of NIS sampled in this study coincide with the low number of marine NIS known from Alaska, which suggests that an opportunity remains to promote awareness and management of the vector to limit NIS influx to the region. This may be particularly relevant for future scenarios of increased vessel traffic and ocean warming, which are likely to interact to increase establishment success of invaders from the south.

Offspring size in a resident species affects community assembly

Offspring size is a trait of fundamental importance that affects the ecology and evolution of a range of organisms. Despite the pervasive impact of offspring size for those offspring, the influence of offspring size on other species in the broader community remains unexplored. Such community-wide effects of offspring size are likely, but they have not been anticipated by theory or explored empirically. For a marine invertebrate community, we manipulated the size and density of offspring of a resident species (Watersipora subtorquata) in the field and examined subsequent community assembly around that resident species. Communities that assembled around larger offspring were denser and less diverse than communities that assembled around smaller offspring. Differences in niche usage by colonies from smaller and larger offspring may be driving these community-level effects. Our results suggest that offspring size is an important but unexplored source of ecological variation and that life-history theory must accommodate the effects of offspring size on community assembly. Life-history theory often assumes that environmental variation drives intraspecific variation in offspring size, and our results show that the converse can also occur.

Arrival of the invasive Watersipora subtorquata (Bryozoa) at Helgoland (Germany, North Sea) on floating macroalgae (Himanthalia)

Arrival of the invasive Watersipora subtorquata (Bryozoa) at Helgoland (Germany, North Sea) on floating macroalgae (Himanthalia)

Predicting climate-induced changes in population dynamics of invasive species in a marine epibenthic community

As climate change and invasive species, both individually and in concert, continue to elicit responses in native communities, we are challenged with finding strategies for predicting the strength of such impacts. The effects of invasive species are often determined by their abundance, and warming temperatures can alter species' demographic rates and, thus, population growth rates. Here, we combined lab experiments, field experiments and observations, and population modeling to predict the population dynamics of three marine invaders in response to climate warming. We projected population growth rate at an ambient and an increased temperature predicted by climate-change scenarios (+4°C) for three invasive species in the epibenthic fouling community of Bodega Harbor, California, USA: the tunicates Botrylloides violaceus and Botryllus schlosseri and the bryozoan Watersipora subtorquata. There was a positive effect of temperature on population growth rate for B. schlosseri, and further analysis revealed that this predicted increase was driven by warming effects on settler growth rate and adult fecundity. Increases indicated for non-native marine fouling species are especially pertinent when considering the potential cascading effects on community composition and functioning that can result from species invasions. Our results highlight the potential for marked increases in an invasive species in response to climate change, as well as the promising role that population modeling can play in elucidating the mechanisms of such responses.

Big changes to a small bay: introduced species and long-term compositional shifts to the fouling community of Morro Bay (CA)

Invasive species are cited as being a threat to communities and ecosystems worldwide, yet few studies have demonstrated invader impacts at these scales. Lack of historic data makes capturing large-scale community shifts problematic. We assessed long-term changes in invertebrate composition to the fouling community of a small estuary with relatively little boat traffic and no ballast water input (Morro Bay, CA). We also compared relative invasiveness of Morro Bay to international harbors (San Francisco Bay and Los Angeles/San Diego harbors). While the proportion of introduced species has not significantly changed from historic records, introduced species now occupy 86.00 % of the primary substrate. Other community shifts include; (1) a state shift to an invasive bryozoan (Watersipora subtorquata) dominated community, (2) a decrease in Mollusc richness and, (3) substantial shifts in abundance of certain species. Compared to larger more actively used harbors, Morro Bay has proportionally fewer introduced species (12.00 %) than San Francisco Bay (50.79 %) or Los Angeles/San Diego Harbors (26.23 %). Our study documents changes to a small relatively isolated estuary with little boat traffic and no ballast water input. We discuss the potential role of invasive species and other natural and anthropogenic factors as drivers of these community wide shifts. Specifically, we discuss how reintroduction of the Southern Sea Otter (Enhydra lutris nereis), an increase in sea stars (Pisaster spp.), climate change and interaction amongst potential drivers support the patterns of shifts in the Morro Bay community.