https://www.srs.fs.usda.gov/pubs/ja/2020/ja_2020_vose_002.pdf

Climate change effects on biodiversity, ecosystems, ecosystem services, and natural resource management in the United States

Recent shifts in the geographic distribution of marine species have been linked to shifts in preferred thermal habitats. These shifts in distribution have already posed challenges for living marine resource management, and there is a strong need for projections of how species might be impacted by future changes in ocean temperatures during the 21st century. We modeled thermal habitat for 686 marine species in the Atlantic and Pacific oceans using long-term ecological survey data from the North American continental shelves. These habitat models were coupled to output from sixteen general circulation models that were run under high (RCP 8.5) and low (RCP 2.6) future greenhouse gas emission scenarios over the 21st century to produce 32 possible future outcomes for each species. The models generally agreed on the magnitude and direction of future shifts for some species (448 or 429 under RCP 8.5 and RCP 2.6, respectively), but strongly disagreed for other species (116 or 120 respectively). This allowed us to identify species with more or less robust predictions. Future shifts in species distributions were generally poleward and followed the coastline, but also varied among regions and species. Species from the U.S. and Canadian west coast including the Gulf of Alaska had the highest projected magnitude shifts in distribution, and many species shifted more than 1000 km under the high greenhouse gas emissions scenario. Following a strong mitigation scenario consistent with the Paris Agreement would likely produce substantially smaller shifts and less disruption to marine management efforts. Our projections offer an important tool for identifying species, fisheries, and management efforts that are particularly vulnerable to climate change impacts.

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Projecting shifts in thermal habitat for 686 species on the North American continental shelf.

Marine species distribution shifts on the U.S. Northeast Continental Shelf under continued ocean warming

Ecological restoration is widely practiced as a means of rehabilitating ecosystems and habitats that have been degraded or impaired through human use or other causes. Restoration practices now are confronted by climate change, which has the potential to influence long-term restoration outcomes. Concepts and attributes from the resilience literature can help improve restoration and monitoring efforts under changing climate conditions. We systematically examined the published literature on ecological resilience to identify biological, chemical, and physical attributes that confer resilience to climate change. We identified 45 attributes explicitly related to climate change and classified them as individual- (9), population- (6), community- (7), ecosystem- (7), or process-level attributes (16). Individual studies defined resilience as resistance to change or recovery from disturbance, and only a few studies explicitly included both concepts in their definition of resilience. We found that individual and population attributes generally are suited to species- or habitat-specific restoration actions and applicable at the population scale. Community attributes are better suited to habitat-specific restoration at the site scale, or system-wide restoration at the ecosystem scale. Ecosystem and process attributes vary considerably in their type and applicability. We summarize these relationships in a decision support table and provide three example applications to illustrate how these classifications can be used to prioritize climate change resilience attributes for specific restoration actions. We suggest that (1) including resilience as an explicit planning objective could increase the success of restoration projects, (2) considering the ecological context and focal scale of a restoration action is essential in choosing appropriate resilience attributes, and (3) certain ecological attributes, such as diversity and connectivity, are more commonly considered to confer resilience because they apply to a wide variety of species and ecosystems. We propose that identifying sources of ecological resilience is a critical step in restoring ecosystems in a changing climate.

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A systematic review of ecological attributes that confer resilience to climate change in environmental restoration.

Recent advances in the application of stock identification methods have revealed inconsistencies between the spatial structure of biological populations and the definition of stock units used in assessment and management. From a fisheries management perspective, stocks are typically assumed to be discrete units with homogeneous vital rates that can be exploited independently of each other. However, the unit stock assumption is often violated leading to spatial mismatches that can bias stock assessment and impede sustainable fisheries management. The primary ecological concern is the potential for overexploitation of unique spawning components, which can lead to loss of productivity and reduced biodiversity along with destabilization of local and regional stock dynamics. Furthermore, ignoring complex population structure and stock connectivity can lead to misperception of the magnitude of fish productivity, which can translate to suboptimal utilization of the resource. We describe approaches that are currently being applied to improve the assessment and management process for marine fish in situations where complex spatial structure has led to an observed mismatch between the scale of biological populations and spatially-defined stock units. The approaches include: (i) status quo management, (ii) "weakest link" management, (iii) spatial and temporal closures, (iv) stock composition analysis, and (v) alteration of stock boundaries. We highlight case studies in the North Atlantic that illustrate each approach and synthesize the lessons learned from these real-world applications. Alignment of biological and management units requires continual monitoring through the application of stock identification methods in conjunction with responsive management to preserve biocomplexity and the natural stability and resilience of fish species.

/pdf/lessons-learned-from-practical-approaches-to-reconcile-58kl1np7de.pdf

Lessons learned from practical approaches to reconcile mismatches between biological population structure and stock units of marine fish

Climate change and decadal variability are impacting marine fish and invertebrate species worldwide and these impacts will continue for the foreseeable future. Quantitative approaches have been developed to examine climate impacts on productivity, abundance, and distribution of various marine fish and invertebrate species. However, it is difficult to apply these approaches to large numbers of species owing to the lack of mechanistic understanding sufficient for quantitative analyses, as well as the lack of scientific infrastructure to support these more detailed studies. Vulnerability assessments provide a framework for evaluating climate impacts over a broad range of species with existing information. These methods combine the exposure of a species to a stressor (climate change and decadal variability) and the sensitivity of species to the stressor. These two components are then combined to estimate an overall vulnerability. Quantitative data are used when available, but qualitative information and expert opinion are used when quantitative data is lacking. Here we conduct a climate vulnerability assessment on 82 fish and invertebrate species in the Northeast U.S. Shelf including exploited, forage, and protected species. We define climate vulnerability as the extent to which abundance or productivity of a species in the region could be impacted by climate change and decadal variability. We find that the overall climate vulnerability is high to very high for approximately half the species assessed; diadromous and benthic invertebrate species exhibit the greatest vulnerability. In addition, the majority of species included in the assessment have a high potential for a change in distribution in response to projected changes in climate. Negative effects of climate change are expected for approximately half of the species assessed, but some species are expected to be positively affected (e.g., increase in productivity or move into the region). These results will inform research and management activities related to understanding and adapting marine fisheries management and conservation to climate change and decadal variability.

/pdf/a-vulnerability-assessment-of-fish-and-invertebrates-to-1j9ahr4ddx.pdf

A Vulnerability Assessment of Fish and Invertebrates to Climate Change on the Northeast U.S. Continental Shelf.

ABSTRACT The ocean quahog, Arctica islandica (Linnaeus 1767), is a commercially important species along the western Atlantic continental shelf. It is a long-lived species, frequently reaching ages over 200 y. Uniquely, it is one of the few bivalves to display sexual dimorphism, in that females grow to sizes larger than those of males. This phenomenon is believed to occur because males reach sexual maturity before females and, thus, have slower growth rates earlier. The growth rates of A. islandica from four sites across the Mid-Atlantic Bight, Georges Bank, Long Island (LI), and north and south of the Hudson Canyon, were measured to determine patterns in growth between males and females. Females begin to outgrow males between the ages of 5 and 15 y at sizes 50–55 mm, though this varies amongst the sites and between decades. Each of the sites is unique in some way, but three sex-dependent growth dynamics are observed. Most commonly, the two sexes diverge in size with females outpacing males in growth rates after the first 5–15 y of life. This outcome occurs at all sites and is generally the most common outcome across decades. In a few cases, female growth rates outpace the males very early in ontogeny. Such cases occur at two sites north of Hudson Canyon, both on the LI continental shelf. Most rarely, the two sexes maintain similar growth rates. This is observed for a few decades at the most southern site. In the population as a whole, these rare outcomes have limited influence on the population so that female-to-male ratio consistently increases with increasing size. This sexually dimorphic growth is not caused by protandry, nor is it compensation for a differential mortality rate between the sexes. Cases where males grow as fast as females may be just as easily indicative of a constraint on female growth as a facilitation on male growth. Egg sizes in A. islandica are larger than those of most other bivalves with planktotrophic larvae. Accordingly, another viable hypothesis is that differential growth is an adaptation to support the large egg sizes in females, where larger female size is essential to counterweigh the consequent reduced fecundity due to larger egg volume.

/pdf/defining-patterns-in-ocean-quahog-arctica-islandica-sexual-1s2vl7uc.pdf

Defining Patterns in Ocean Quahog (Arctica islandica) Sexual Dimorphism along the Mid-Atlantic Bight

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/mcf2.10223

Eric Robillard

Papers

A Vulnerability Assessment of Fish and Invertebrates to Climate Change on the Northeast U.S. Continental Shelf.

Defining Patterns in Ocean Quahog (Arctica islandica) Sexual Dimorphism along the Mid-Atlantic Bight

Life History Assessment of Cusk, a Data‐Poor Species, in U.S. Waters