Changes In the biogeographic distribution of the trochid gastropods Osilinus lineatus (da Costa) and Gibbula umbilicalis (da Costa) in response to global climate change: range dynamics and physiological mechanisms

There is an urgent need to understand the effects of climatic variability on species' distributions. This thesis uses an integrative approach to identify and explain the changes in geographical distribution of two rocky intertidal, warm water species of trochid gastropod, Osilinus lineatus (da Costa) and Gibbula umbiiicalis (da Costa) that have occurred since the onset of rapid climate warming in the mid-1980s. The potential physiological mechanisms causing the range shifts are examined, and the effects on population dynamics quantified. I resurveyed sites in Britain and northern France previously surveyed by Southward & Crisp (1950s), Hawthorne (1960s) and Kendall, Williamson & Lewis (1970s and 1980s) to record the current north and east distributional limits of Osilinus lineatus and Gibbula umbilicalis between 2002-2004. The range of O. lineatus had extended north by 100km and east by 55km since 1986, and G. umbilicalis had extended its northern limits by 85km since 1985. Concordant increases in abundance had occurred in both species across all quantitative survey sites between 1985/6 and 2002-2004. Studies of the effects of increased sea temperatures on gonad development and spawning were run concurrently in the field and the laboratory. The reproductive cycle occurred 2 months earlier in all field populations studied over a distance of 4° latitude during the warmer years of 2003 and 2004, compared to studies made in the cooler 1960s and 1980s. No gonad re-maturation was observed in field or laboratory populations. Analyses of 0, lineatus and G. umbilicalis population data from the 1970s, 1980s and 2000s showed that recruitment success had increased as winter sea temperatures had warmed. Field and laboratory studies of survival and growth of newly settled recruits was positively related to sea temperature, with greater survival at increased winter temperatures. Plasticity in the timing of the reproductive cycle and increased recruitment success in response to increased sea temperatures are suggested as the physiological mechanisms driving range extensions in O. lineatus and G. umbilicalis during the current period of rapid climate warmin

The relation between productivity and species diversity in temperate-arctic marine ecosystems

Energy variables, such as evapotranspiration, temperature, and productivity explain significant variation in the diversity of many groups of terrestrial plants and animals at local to global scales. Although the ocean represents the largest continuous habitat on earth with a vast spectrum of primary productivity and species richness, little is known about how productivity influences species diversity in marine systems. To search for general relationships between productivity and species richness in the ocean, we analyzed data from three different benthic marine ecosystems (epifaunal communities on subtidal rock walls, on navigation buoys in the Gulf of St. Lawrence, and Canadian Arctic macrobenthos) across local to continental spatial scales (1000 km) using a standardized proxy for productivity, satellite-derived chlorophyll a. Theoretically, the form of the function between productivity and species richness is either monotonically increasing or decreasing, or curvilinear (hump- or U-shaped). We found three negative linear and three hump-shaped relationships between chlorophyll a and species richness out of 10 independent comparisons. Scale dependence was suggested by more prevalent diversity-productivity relationships at smaller (local, landscape) than larger (regional, continental) spatial scales. Differences in the form of the functions were more closely allied with community type than with scale, as negative linear functions were restricted to sessile epifauna while hump-shaped functions occurred in Arctic macrobenthos (mixed epifauna, infauna). In two of the data sets, (St. Lawrence epifauna and Arctic macrobenthos) significant effects of chlorophyll a co-varied with the effects of salinity, suggesting that environmental stress as well as productivity influences diversity in these marine systems. The co-varying effect of salinity may commonly arise in broad-scale studies of productivity and diversity in marine ecosystems when attempting to sample the largest range of productivity, often encompassing a coastal-oceanic gradient

The genome sequence of the common limpet, Patella vulgata (Linnaeus, 1758)

We present a genome assembly from an individual Patella vulgata (the common limpet; Mollusca; Gastropoda; Patellogastropoda; Patellidae). The genome sequence is 695.4 megabases in span. Most of the assembly is scaffolded into 9 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 14.93 kilobases in length. Gene annotation of this assembly on Ensembl identified 19,378 protein coding genes.</ns4:p

Shoreline sentinels of global change show the consequences of extreme events.

Anthropogenic climate change along with the more frequent extreme weather it prompts, are having direct and indirect effects on distributions and abundance of species with consequence for community structure-especially if habitat providers are lost. Rocky shores have long been recognized as tractable experimental arenas for ecology contributing to theory. They have also emerged as important sentinel systems for tracking climate change responses of marine biodiversity and ecosystems, capitalizing on both historic broadscale surveys and time series. Combining these twin traditions is a powerful approach for better understanding and forecasting climate change impacts. Sustained observing allows extreme events to be detected and explored by in-parallel experimentation

Red List for British seaweeds: evaluating the IUCN methodology for non-standard marine organisms

The IUCN Red List of Threatened Species is an authoritative tool in biodiversity conservation. Whilst IUCN criteria have been applied successfully to groups such as birds and mammals, a Red List assessment of British seaweeds in 2021 revealed that the categories to which seaweed species were assigned were dependent on how the criteria were applied. Here, this seaweed assessment is used as a case study with which to evaluate the IUCN methodology for use with ‘non-standard’ groups of organisms. A data-driven assessment of red (Rhodophyta), green (Chlorophyta) and brown (Phaeophyceae) seaweeds, which applied three (A, B and D) of the five IUCN criteria (A–E), categorized 13% of 617 British species as threatened. Following peer review, only 7% of species were categorized as threatened (1% Critically Endangered—CR, 3% Endangered—EN, 3% Vulnerable—VU), and 55% as Data Deficient. This reduction in species categorized as threatened suggests that strict application of the IUCN criteria may, at least for the seaweeds, over-estimate threat. As a result of this assessment, recommendations include the need for a more unified monitoring system and a review of the suitability for/application of the IUCN assessment criteria to some types of organisms. For example, in clonal populations, it is not possible to count individuals, and complex life histories cause additional complications. IUCN criteria must be applicable to a wide range of organisms, including seaweeds

Spatial scales of variance in abundance of intertidal species: effects of region, dispersal mode, and trophic level

Determination of the pattern of variation in population abundance among spatial scales offers much insight into the potential regulating factors. Here we offer a method of quantifying spatial variance on a range of scales derived by sampling of irregularly spaced sites along complex coastlines. We use it to determine whether the nature of spatial variance depends on the trophic level or the mode of dispersal of the species involved and the role of the complexity of the underlying habitat. A least-cost distance model was used to determine distances by sea between all pairs of sites. Ordination of this distance matrix using multidimensional scaling allowed estimation of variance components with hierarchical ANOVA at nested spatial scales using spatial windows. By repeatedly moving these spatial windows and using a second set of spatial scales, average variance scale functions were derived for 50+ species in the UK rocky intertidal. Variance spectra for most species were well described by the inverse power law (1/f?) for noise spectra, with values for the exponent ranging from 0 to 1.1. At higher trophic levels (herbivores and carnivores), those species with planktonic dispersal had significantly higher ? values, indicating greater large- than small-scale variability, as did those on simpler coastlines (southwestern England and Wales vs. western Scotland). Average abundance and proportional incidence of species had the strongest influence on ? values, with those of intermediate abundance and incidence having much greater large-scale variance (? ? 0.5) than rare or ubiquitous species (? ? 0)

Scaling up experimental ocean acidification and warming research: from individuals to the ecosystem

NERC UK Ocean Acidification Research Programme NE/HO1747X/1 The full text is under embargo until 17.08.1

Aspects of Benthic Decapod Diversity and Distribution from Rocky Nearshore Habitat at Geographically Widely Dispersed Sites

Relationships of diversity, distribution and abundance of benthic decapods in intertidal and shallow subtidal waters to 10 m depth are explored based on data obtained using a standardized protocol of globally-distributed samples. Results indicate that decapod species richness overall is low within the nearshore, typically ranging from one to six taxa per site (mean = 4.5). Regionally the Gulf of Alaska decapod crustacean community structure was distinguishable by depth, multivariate analysis indicating increasing change with depth, where assemblages of the high and mid tide, low tide and 1 m, and 5 and 10 m strata formed three distinct groups. Univariate analysis showed species richness increasing from the high intertidal zone to 1 m subtidally, with distinct depth preferences among the 23 species. A similar depth trend but with peak richness at 5 m was observed when all global data were combined. Analysis of latitudinal trends, confined by data limitations, was equivocal on a global scale. While significant latitudinal differences existed in community structure among ecoregions, a semi-linear trend in changing community structure from the Arctic to lower latitudes did not hold when including tropical results. Among boreal regions the Canadian Atlantic was relatively species poor compared to the Gulf of Alaska, whereas the Caribbean and Sea of Japan appeared to be species hot spots. While species poor, samples from the Canadian Atlantic were the most diverse at the higher infraordinal level. Linking 11 environmental variables available for all sites to the best fit family-based biotic pattern showed a significant relationship, with the single best explanatory variable being the level of organic pollution and the best combination overall being organic pollution and primary productivity. While data limitations restrict conclusions in a global context, results are seen as a first-cut contribution useful in generating discussion and more in-depth work in the still poorly understood field of biodiversity distribution

Moving Toward a Strategy for Addressing Climate Displacement of Marine Resources: A Proof-of-Concept

Realistic predictions of climate change effects on natural resources are central to adaptation policies that try to reduce these impacts. However, most current forecasting approaches do not incorporate species-specific, process-based biological information, which limits their ability to inform actionable strategies. Mechanistic approaches, incorporating quantitative information on functional traits, can potentially predict species- and population-specific responses that result from the cumulative impacts of small-scale processes acting at the organismal level, and can be used to infer population-level dynamics and inform natural resources management. Here we present a proof-of-concept study using the European anchovy as a model species that shows how a trait-based, mechanistic species distribution model can be used to explore the vulnerability of marine species to environmental changes, producing quantitative outputs useful for informing fisheries management. We crossed scenarios of temperature and food to generate quantitative maps of selected mechanistic model outcomes (e.g., Maximum Length and Total Reproductive Output). These results highlight changing patterns of source and sink spawning areas as well as the incidence of reproductive failure. This study demonstrates that model predictions based on functional traits can reduce the degree of uncertainty when forecasting future trends of fish stocks. However, to be effective they must be based on high spatial- and temporal resolution environmental data. Such a sensitive and spatially explicit predictive approach may be used to inform more effective adaptive management strategies of resources in novel climatic conditions