1,721,049 research outputs found
Data from: Going with the flow: the role of ocean circulation in global marine ecosystems under a changing climate
No full textOcean warming, acidification, deoxygenation and reduced productivity are widely considered to be the major stressors to ocean ecosystems induced by emissions of CO2. However, an overlooked stressor is the change in ocean circulation in response to climate change. Strong changes in the intensity and position of the western boundary currents have already been observed, and the consequences of such changes for ecosystems are beginning to emerge. In this study, we address climatically induced changes in ocean circulation on a global scale but relevant to propagule dispersal for species inhabiting global shelf ecosystems, using a high resolution global ocean model run under the IPCC RCP 8.5 scenario. The ¼ degree model resolution allows improved regional realism of the ocean circulation beyond that of available CMIP5-class models. We use a Lagrangian approach forced by modelled ocean circulation to simulate the circulation pathways that disperse planktonic life stages. Based on trajectory backtracking, we identify present-day coastal retention, dominant flow and dispersal range for coastal regions at the global scale. Projecting into the future, we identify areas of the strongest projected circulation change and present regional examples with the most significant modifications in their dominant pathways. Climatically-induced changes in ocean circulation should be considered as an additional stressor of marine ecosystems in a similar way to ocean warming or acidification.,Asia and Oceania releasesThe dataset contains the particle tracking runs for the coastline of Asia and Oceania. 3 runs were carried out using the velocity field of three different decades: 2000-09, 2050-59 and 2090-99 and released particles were tracked backwards in time for 12 months.Releases_Asia_Oceania.tar.gzReleases Europe and AfricaReleases_Europe_Africa.tar.gzReleases North AmericaReleases_Nth_America.tar.gzReleases South AmericaReleases_Sth_America.tar.gzMatlab script to extract each ASCIIdataA step by step procedure to extract trajectories from the datasetsExtract_ASCIIdata.mExplanation_ASCII_dataDescription of datasets content</span
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Impacts of climate change across generations of marine invertebrate species with complex life cycles
No full textClimate is changing at unprecedented rates and marine species worldwide will need to adapt, acclimate, or shift their ranges to persist. The majority of marine organisms have complex life cycles, in which developmental stages differ in morphology, physiology, habitat, and environmental tolerances. To better predict the impacts of climate change, we must understand how each stage responds and copes with ocean warming – especially early life stages that are most vulnerable to environmental stress. In Chapter 1, I investigate the effects of environmental conditions during development on larval survival in Mexacanthina lugubris, a whelk species shifting its range northward along the west coast of the United States in response to climate change. We found no difference in reproductive output or larval survival across shore heights, suggesting egg-laying behavior may buffer developing stages from thermal stress. In Chapter 2, I test the influence of parental environments on offspring thermal tolerances in an important foundation species, the California mussel (Mytilus californianus). We observed parental effects across one generation, where adult mussels exposed to warmer habitats yielded less tolerant offspring. We also found indicators of trade-offs in energy investment where mussels in low stress environments had higher reproductive condition and larger egg diameters. Finally, in Chapter 3, I explore the critical time windows that influence transgenerational plasticity across generations in marine invertebrates using a meta-analysis. This meta-analysis revealed that the outcomes of transgenerational plasticity vary by trait type, taxonomical groups, and life history traits. I found that gametogenesis is a key window in a parent’s life for experiencing an environmental stressor to result in transgenerational plasticity. Together these results elucidate some of the factors and coping mechanisms that will determine the persistence of marine species under climate change. My dissertation highlights the importance of understanding the impact of climate change across life stages and generations when predicting the survival of marine invertebrates
Rarity and beta diversity assessment as tools for guiding conservation strategies in marine tropical subtidal communities
Get PDFAim: Our aim was to uncover patterns of distribution of marine subtidal rocky reef communities across six taxonomic groups and decompose the relative roles of species loss and turnover in total community variation. Additionally, we propose an easily calculated index that can be used to highlight areas with unique species composition for conservation planning. We estimated the strengths of associations between environmental factors and species richness and rarity. Location: Ilha Grande Bay, Brazil, covering about 150,000 ha harbouring different marine habitats. Methods: We used the Marine Rapid Assessment Protocol at 42 sites to gather information on environmental variables and species in six subtidal marine groups. We determined “singular” sites as the regions harbouring higher numbers of rare species. Then, we estimated the roles of species loss and turnover on the observed total variation among sites. We used Generalized Linear Model to partition the relative importance of the selected environmental factors in driving variation in species richness and singularity. Results: The singularity index and richness showed that the bay could be divided into three subregions for subtidal communities. Richness and rarity were structured at different spatial scales and associated with environmental variables related to water productivity and nutrients but varied among taxonomic groups. Community variation over space was largely associated with turnover of species. Main conclusions: Higher singularity and richness on the western side of the bay and around the main island suggested that these regions should be conservation priorities, but high species turnover across the whole bay indicated that portions of the central channel should be included in conservation strategies. This draws attention to the importance of community variation rather than just species numbers in conservation and management planning. The high species turnover indicated that these rocky reefs have high beta diversity when compared to other studied biological systems
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Climate Driven Range Shifts Impact Communities Through Altered Species Interactions
Get PDFClimate change is likely the greatest threat to global biodiversity and ecosystem functioning, and it is becoming increasingly apparent that understanding the effects of climate change requires going beyond single species or limited spatial scales. Climate change will impact species and communities through both direct and indirect effects, as mediated by species interactions, and incorporating these indirect effects can increase the ability to track shifting species distributions. I used a space-for-time approach to test if incorporating indirect effects increases predictive ability through surveys of vertical distributions of predators (sea stars) and prey species (mussels) spanning a thermal gradient along the West Coast. Prey distributions were directly influenced by temperature, but there was also a significant indirect effect of temperature, as mediated by predator distributions. Under future climate change, mussel ranges may undergo vertical shifts towards subtidal habitats, allowing for localized persistence of mussels and their associated species. However, both local and broad scale range-shifts can displace other species or alter community and ecosystem processes. Despite inherent differences between introduced and range-shifting species, impacts can occur via analogous mechanisms, and the magnitude of impacts can be similar. Risk assessments developed for invasive species provide a useful tool for assessing potential impacts of range-shifting species. Altered species interactions and communities can be observed locally in southern California intertidal communities, where the whelk Mexacanthina lugubris is undergoing a northward range shift. I assessed the impacts of Mexacanthina on local species, through long-term field surveys, coupled with manipulative experiments to assess current and future impacts on competitors. Mexacanthina is now well established and utilizes analogous resources and habitats as native whelk species. Mexacanthina can also survive at warmer temperatures than native whelks, suggesting that range-shifters may have a competitive advantage in a warming climate. The persistence of some species at the expense of others underscores the complexities of conservation in the era of climate change. My thesis research explores this dichotomy by examining how species interactions can indirectly alter distributions (Ch. 1), which traits are indicative of problematic range-shifters (Ch. 2), and how a range-shifting species is altering southern California communities (Ch. 3)
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Sensitivity and Exposure to Climate Change across Life Stages of Marine Invertebrates
Get PDFClimate change is resulting in unprecedented increases in both mean and extreme global temperatures, with widespread effects on Earth’s biota. It is difficult to predict the impacts of climate change, and resulting extreme heat events, on species with complex life cycles. Throughout their complex life cycles, life stages of marine invertebrates may experience unequal levels of environmental stress (exposure) and have differing thermal tolerances (sensitivity), which vary in space and time. A meta-analysis of differences in sensitivity across life stages of marine invertebrates revealed that, when exposed to the same levels of warming, younger life stages are more sensitive than older life stages (Chapter 1). We used field observations of environmental conditions experienced coupled with laboratory assessments of thermal tolerance to investigate whether thermal safety margins differed across three benthic life stages of the California mussel, Mytilus californianus. Our results demonstrated that thermal sensitivity decreased throughout ontogeny, and, since exposure trends were similar across life stages, sensitivity drove thermal safety margin differences across life stages and approaches (Chapter 2). Finally, we investigated how sensitivity and exposure vary across small-scale habitats in space and over four seasons for one year, calculating mortality risk for two benthic life stages of mussels. We deployed temperature loggers to document habitat-specific exposure patterns, conducted lab thermal tolerance assays to calculate sensitivity, and used field surveys to determine whether risk patterns were reflected in abundance distributions. We found that sensitivity was more variable across seasons (time) than small-scale habitats (space), resulting in high temporal variation in mortality risk (Chapter 3). Together, these results highlight the importance of incorporating life stage and seasonal dynamics when predicting impacts of climate change on the survival of marine invertebrates
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New Around Here? The Assembly of Invasive Species and Impacts of Range-Expanding Species
No full textThe redistribution of biodiversity is among the most pervasive aspects of global change, affecting species and ecosystems worldwide. This redistribution can occur via two primary avenues: (1) the intentional or unintentional relocation of species by humans, resulting in the introduction of exotic—or in some cases, invasive—species, and (2) the natural, climate-driven dispersal of species outside their historic ranges due to increasing warming (hereafter referred to as range shifts or range expansions). As these species redistribute, their abilities to establish in novel communities and their impacts depend on biotic interactions with resident species. Whether resident species, both native and established exotics, act to resist or promote subsequent invasions is largely unknown. Additionally, while there is a wealth of literature and frameworks for anticipating impacts of human-driven invaders, the impacts of climate-driven expanding species are rarely quantified, and no such predictive frameworks exist. Therefore, the aims of this dissertation are to understand how resident species influence the success of subsequent invasions, and to empirically quantify impacts of range expansions and create a general framework for anticipating the impacts of expanding species in their novel communities. In Chapter 1, I assessed how diversity of resident native and exotic species affected the likelihood of further exotic establishment via observations in a subtidal epibenthic community. I found that both native and exotic species reduced exotic establishment during community development but that exotic species became numerically dominant in all cases. In Chapter 2, I conducted observational surveys and a manipulative field experiment in the historic and expanded ranges of two range-expanding intertidal whelks to (1) quantify impacts on prey and community diversity and (2) assess how impacts relate to expander abundance and compare impacts across ranges. I found that these expanding predators reduced prey abundances linearly (rather than nonlinearly, as with invasive predators) but had minimal impacts on community diversity. Importantly, impacts were consistent between historic and expanded ranges suggesting that impacts are, to a degree, predictable but could in some contexts be greater in the expanded range. Finally, in Chapter 3, I present the results of a global synthesis of more than 350 marine expanding species (spanning 13 phyla), assessing whether expansion impacts can generally be predicted from expanders’ impacts in their historic communities or trophic levels, both which are useful indicators of invader impacts. I found that expanders with strong impacts in their historic ranges generally have strong impacts in their expanded ranges. Expansion impacts are also predicted by expander trophic level, with higher trophic level expanders having more negative impacts than lower trophic expanders. Collectively, my dissertation contributes insights into drivers of invasive species establishment and provides a novel framework for anticipating the impacts of biodiversity redistribution in an era of global change
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The shifting ecological impacts of dominant and invasive marine species under climate change
Get PDFGlobal change is impacting ecosystems worldwide, driving widespread biodiversity loss and disrupting a broad spectrum of ecological processes. Ecosystems are organized by interactions among species, which dictate everything from species composition to how biomass and energy flow through the system. Only by studying the effects of global change in the context of existing ecological structures and species interactions can the impacts be fully understood. My dissertation research has focused on the ways in which climate change affects the ecological roles of species: whether by altering the relative importance of common species in ecosystems, directly impacting ecosystem function via species loss, or accelerating the proliferation of invasive species. In my first chapter, I consider the potential for an abundant marine producer to engineer habitat for other species and how that role may shift with climate change. I found that this dominant alga raised pH when in isolation but not in the context of a tide pool community, suggesting that the most abundant species do not necessarily affect the impacts of global change in coastal ecosystems. My second chapter focuses on the contributions of dominant species to ecosystem multifunctionality in coastal areas, as well as the potential effects of dominant species loss on ecosystem multifunctionality. I found that a dominant producer and a dominant consumer had largely opposite effects on ecosystem function and that the loss of the producer altered the functional impact of the consumer, suggesting that species loss may impact ecosystem multifunctionality beyond the functional footprint of the individual species. In my third chapter, I identified the ways that climate change is likely to influence factors that historically limited species invasion in high-latitude, marine ecosystems. Each of these invasion barriers is likely to become increasingly porous, potentially increasing invasions in high-latitude areas in decades to come. The results of this research could be incorporated into (1) conservation plans, sharpening the focus on species which have the greatest ecological impact, either by stabilizing environmental conditions or by driving ecosystem function, and (2) invasive species management strategies, by highlighting the increasing vulnerability of high-latitude ecosystems to species invasion under warming conditions and stressing the importance of international cooperation in monitoring programs
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From Individual to Ecosystem: Multi-Stressor Effects of Acidification and Warming on the Physiological Responses of Coastal Marine Invertebrates
Get PDFClimate change is directly impacting the services humans derive from the sea at an accelerated rate. Ocean warming and acidification (i.e., a decrease in ocean pH) are leading to modifications in population sizes and ecosystem functioning. The observed shifts in these higher order processes are a direct result of individuals’ responses (i.e., physiology, including metabolism, growth, calcification, and survival) occurring within communities. Natural variation in past environmental exposure experienced by individuals may lead to greater population resilience, or it may push individuals past physiological thresholds leading to increased sensitivity and vulnerability to climate change. Thus, we need to determine how individual-level physiological responses to climate change scale up to influence marine ecosystems. Rocky intertidal habitats are an ideal study system for evaluating the relationships between individual physiological responses, ecosystem functioning, and climate change. Tide pools possess unique thermal and pH environments and can be monitored under natural conditions or manipulated with field-experiments over daily and seasonal time scales, creating natural “experimental mesocosms”. In addition, many species within rocky intertidal habitats are exposed to environmental conditions close to their tolerance limits, increasing their potential vulnerability to climate change. In Chapter 1, by utilizing the unique thermal environments of tide pools, I showed that across small spatial scales (pools), thermal history influences thermal sensitivity of marine invertebrates for short-term time intervals (1-week and 1-day) and that this relationship differs seasonally and between species with differing traits, including mobility. This suggests that variability in thermal responses among individuals may allow for a natural buffer at a population level in response to climate change.
Multiple stressors may affect individuals independently or interactively, amplifying or mitigating effects. Thus, to determine the impacts of climate change, in Chapter 2, I used a 6-month long field manipulation of ocean warming and acidification in tide pools. I examined the combined effects of warming and acidification on the shell structure (shell thickness and corrosion) and functional properties (shell strength) of the ecologically critical species, the Pacific blue mussel (Mytilus trossulus). Acidification led to thinner, weaker, and more corroded shells whereas combined warming and acidification resulted in an increase in shell strength. My results suggest that to some degree, warming may mitigate the negative impacts of acidification on this mollusk species.
Lastly, in Chapter 3, I characterize how warming and acidification, individually and interactively, impact net ecosystem calcification and the individual and population-level mechanisms driving impacts on net ecosystem calcification. Net ecosystem calcification tended to increase during the day and decrease at night; however, addition of CO2 during the hottest months led to decreased net ecosystem calcification and increased dissolution during both day and night. I found that individual mussel metabolic rates increased significantly in the presence of elevated CO2 and increased daily maximum of pool temperatures. Through this individual-level pathway, pH and temperature had a strong impact on the metabolic rates of individuals ultimately resulting in changes in net ecosystem calcification. On the other hand, greater mussel abundance was associated with increased net ecosystem calcification. Yet, with the addition of CO2, calcification decreased even in pools with the highest abundance of mussels, indicating that there are other pathways by which changes in pH can drive alterations in net ecosystem calcification.
My dissertation reveals how species’ traits and natural thermal variation from short-term to seasonal time scales influence metabolic sensitivity to future warming among individuals (Ch. 1), independent climate stressors can negatively impact shellfish in situ, whereas the combined interactive effects between multiple stressors can lead to mitigation of the negative impacts of a single stressor alone (Ch. 2), and that ecosystem-level consequences of climate change are mediated by the abundance of dominant calcifiers and that this effect is dependent on the magnitude of acidification and warming (Ch. 3)
Impact assessment of coastal marine range shifts to support proactive management
No full textClimate change is reshuffling Earth's biota as species ranges shift to track increasing habitat temperatures. While redistribution may be necessary for species persistence, there can also be impacts on existing communities upon arrival of novel, range-shifting species. Anticipating the beneficial versus deleterious impacts of range-shifting species is essential for determining whether active management is needed, which could include employing strategies from facilitation (eg managed relocation) to suppression (eg prevention/control). We employ an impact assessment protocol developed for invasive species to evaluate potential consequences of range shifts in coastal marine ecosystems of North America. Our review demonstrates how invasion impact assessment combined with species vulnerability assessment could support decisions about management of range shifts. We found that ~50% of these shifting coastal species have had negative impacts in their expanded range. Thus, the importance of proactive management is likely to increase as the number and extent of range shifts accelerates.The uploaded data includes an Excel spreadsheet with formatting that contains the database and the metadata on separate sheets. In addition, there are four .csv files. First, the impact assessment database. Second, metadata with description of columns. Third, the reference list of country names used, and fourth, the reference list for habitats. A second spreadsheet with meta-data information about columns. See README file for more information.
Funding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: ICER-1852060Identification of study species
We identified 40 marine species with documented shifts in range limits along the coastline (<15 km from shore) of North America, including plants, invertebrates, fish, a protist, and a bird. Of these, 26 species were compiled by Sorte et al. (2010), and we added 14 species from an updated literature review. We searched Google Scholar (on 08/20/2019) using this search string: marine "range expansion" species "range shift". We reviewed titles and, when appropriate, abstracts and text of the first 600 results, identifying 12 additional species from eight papers. We added two species (Brachidontes adamsianus and Mexacanthina lugubris) from our literature files and personal observations. We excluded migratory or pelagic species with large biogeographic ranges, for which it was difficult to confirm historical native ranges.
Review of published impacts
Evidence of species' impacts was compiled from online database searches and literature review. We conducted individual Web of Science searches for the 40 shifting species using each species' scientific name (and synonyms). Papers reporting species impacts were identified by reviewing titles and abstracts. For species with >800 Web of Science results, the first 400 results were scanned and remaining results were filtered using this search string: "ecology" OR "invas*" OR "impact". For species with <100 Web of Science results, we also performed Google Scholar searches, and relevant papers were identified from the first 400 results. Additional impact studies were added opportunistically from citations within papers found in database searches). In total, we reviewed 11,508 papers for this impact assessment of 40 range-shifting species.
Impact assessment
We evaluated environmental and socioeconomic impacts using modified versions of the Environmental Impact Classification of Alien Taxa (EICAT; Hawkins et al. 2015) and Socio-economic Impact Classification of Alien Taxa (SEICAT; Bacher et al. 2017) protocols. The EICAT and SEICAT protocols focus on impacts on native, non-human populations and human activities, respectively. Primary modifications were the inclusion of beneficial (rather than only detrimental) impacts and use of studies in species' native and expanded ranges to estimate impacts (rather than only non-native ranges).
Impacts were classified by mechanism. The following are mechanisms that we identified as responsible for negative impacts by shifting species on native (non-human) species: competition, predation, herbivory, parasitism, disease transmission, interaction with other invaders, biofouling, bioturbation, physical disturbance, poisoning/toxicity, and "other" negative impacts (including those with an unknown mechanism). We also found evidence of positive ecological impacts by the following mechanisms: food provisioning, habitat provisioning, and "other" positive impacts. Our SEICAT analysis revealed socioeconomic impacts associated with alterations in health, material and immaterial assets, and social, spiritual or cultural relations.We assigned levels of impacts based on categories described in the EICAT and SEICAT protocols (Hawkins et al. 2015, Bacher et al. 2017). Impacts range across a semi-quantitative gradient from 1 (lowest) to 5 (highest). For each published study, we scored impacts of shifting species based on the highest level response from the categories. Impact scores, thus, represent the maximum impact that has been observed. Both EICAT and SEICAT protocols were modified to incorporate positive impacts, essentially switching the direction or sign of negative impacts (Table 1). Species for which we found no published papers on impacts were categorized as "data deficient".
For both EICAT and SEICAT assessments, we collected additional information about the shifting species and study. These characteristics included taxonomic classifications, study location, and whether the study was conducted in the shifting species' "native" or non-native, "expanded" range. Ranges were defined as "native"or "expanded" based primarily on documentation within the source reporting the range shift. "Expanded" ranges were designated as such conservatively, acknowledging potential lack of benchmark data for species ranges, with most range shifts documented after 1985 (Sorte et al. 2010). (Virnstein and Hall 2009, Canning-Clode 2011, Goddard et al. 2011, Poloczanska et al. 2013, Gericke et al. 2014, Heck et al. 2015, Cannizzo and Griffen 2016, Timbs et al. 2019
Mortality risk across life stages and habitats of an intertidal mussel (Mytilus californianus)
No full textThese data are associated with the manuscript "Mortality risk across life stages and habitats of an intertidal mussel (Mytilus californianus)". Code for statsitical analyses can be found on L. Pandori's GitHub (https://github.com/llmpandori/Mussel_Habitat_Risk). Feel free to conatct L. Pandori with any requests regarding this dataset
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