Global patterns of marine biodiversity and the potential impact of climate change

Marine species are highly susceptible to climate change as demonstrated by several studies. However, most of these studies focus on few species or on restricted geographical areas. Within this context, the main goal of my dissertation is to characterize global patterns and forecast the effects of climate change on marine biodiversity. This work is the first macroecological approach to investigate the effects of climate change in the marine realm on key commercial marine groups, namely coastal lobsters (125 species), cephalopods (161 species) and small pelagic fish (103 species). Here I aimed to improve our understanding of how projected changes in species distribution might affect key marine species diversity, body size, assemblage composition, variations in catch, and finally infer on the potential impacts for fisheries worldwide. Using Ecological Niche Models (ENMs) the projected global diversity patterns of the analyzed species generally showed higher values in tropical areas and lower values in higher latitudes. Nonetheless, these patterns were projected to change significantly by the end of the century, with a general tendency of species tracking adequate habitat suitability to higher latitudes. The results obtained provide critical information to anticipate negative impacts of climate change on marine biodiversity and should be considered in future studies, as they highlight climate hot-spot areas or with highly vulnerable species. Ultimately, it is crucial to evaluate species adaptation potential and develop hybrid models that better can guide future political decisions on conservation and management measures; RESUMO: Padrões globais da biodiversidade marinha e o potencial impacto das alterações climáticas As espécies marinhas são altamente suscetíveis às alterações climáticas, como demonstrado em numerosos estudos. Porém muitos desses estudos focam-se num número reduzido de espécies ou numa determinada área geográfica (local ou regional). Neste contexto, a presente dissertação tem como objetivo investigar os padrões globais de biodiversidade marinha e projetar como estes poderão estar modificados no final do século. Este trabalho constitui a primeira abordagem macroecológica que investiga, numa escala global, os impactos das alterações climáticas em taxa marinhos com alto interesse económico, como lagostas (125 espécies), cefalópodes (161 espécies) e pequenos peixes pelágicos (103 espécies). Os padrões globais de biodiversidade marinha para todos os taxa analisados mostram maior riqueza na zona dos trópicos e menor número de espécies nas maiores latitudes. No entanto, estes padrões podem sofrer modificações significativas até ao final do século verificando-se uma tendência generalizada das espécies migrarem para latitudes maiores de forma a encontrarem refúgio em áreas com boa adequação ambiental. Os modelos usados nesta tese (modelos de nicho ecológico) projetam alterações significativas na distribuição das espécies analisadas, com impactos profundos na riqueza e abundância em áreas vitais para a saúde dos oceanos e para as pescas, a longo prazo. Esta dissertação representa um contributo importante para o conhecimento dos padrões globais da biodiversidade nos oceanos futuros. Servindo os seus resultados para orientar estudos pormenorizados em áreas de risco elevado ou com espécies mais vulneráveis e informar a tomada de decisões com vista a proteção de espécies marinhas com elevado valor económico e ambiental. Contudo, atendendo aos efeitos das alterações climáticas já sentidos nos oceanos, é crucial avaliar a capacidade de adaptação destas espécies e encontrar modelos híbridos que melhor nos permitam orientar medidas de gestão e conservação futuras

Padrões globais da biodiversidade marinha e o potencial impacto das alterações climáticas

Universidade de Évora - Instituto de Investigação e Formação Avançada -Programa de Doutoramento em Biologia; 5 capítulos; 125 pp.[EN] Marine species are highly susceptible to climate change as demonstrated by several studies. However, most of these studies focus on few species or on restricted geographical areas. Within this context, the main goal of my dissertation is to characterize global patterns and forecast the effects of climate change on marine biodiversity. This work is the first macroecological approach to investigate the effects of climate change in the marine realm on key commercial marine groups, namely coastal lobsters (125 species), cephalopods (161 species) and small pelagic fish (103 species). Here I aimed to improve our understanding of how projected changes in species distribution might affect key marine species diversity, body size, assemblage composition, variations in catch, and finally infer on the potential impacts for fisheries worldwide. Using Ecological Niche Models (ENMs) the projected global diversity patterns of the analyzed species generally showed higher values in tropical areas and lower values in higher latitudes. Nonetheless, these patterns were projected to change significantly by the end of the century, with a general tendency of species tracking adequate habitat suitability to higher latitudes. The results obtained provide critical information to anticipate negative impacts of climate change on marine biodiversity and should be considered in future studies, as they highlight climate hot-spot areas or with highly vulnerable species. Ultimately, it is crucial to evaluate species adaptation potential and develop hybrid models that better can guide future political decisions on conservation and management measures.[POR] As espécies marinhas são altamente suscetíveis às alterações climáticas, como demonstrado em numerosos estudos. Porém muitos desses estudos focam-se num número reduzido de espécies ou numa determinada área geográfica (local ou regional). Neste contexto, a presente dissertação tem como objetivo investigar os padrões globais de biodiversidade marinha e projetar como estes poderão estar modificados no final do século. Este trabalho constitui a primeira abordagem macroecológica que investiga, numa escala global, os impactos das alterações climáticas em taxa marinhos com alto interesse económico, como lagostas (125 espécies), cefalópodes (161 espécies) e pequenos peixes pelágicos (103 espécies). Os padrões globais de biodiversidade marinha para todos os taxa analisados mostram maior riqueza na zona dos trópicos e menor número de espécies nas maiores latitudes. No entanto, estes padrões podem sofrer modificações significativas até ao final do século verificando-se uma tendência generalizada das espécies migrarem para latitudes maiores de forma a encontrarem refúgio em áreas com boa adequação ambiental. Os modelos usados nesta tese (modelos de nicho ecológico) projetam alterações significativas na distribuição das espécies analisadas, com impactos profundos na riqueza e abundância em áreas vitais para a saúde dos oceanos e para as pescas, a longo prazo. Esta dissertação representa um contributo importante para o conhecimento dos padrões globais da biodiversidade nos oceanos futuros. Servindo os seus resultados para orientar estudos pormenorizados em áreas de risco elevado ou com espécies mais vulneráveis e informar a tomada de decisões com vista a proteção de espécies marinhas com elevado valor económico e ambiental. Contudo, atendendo aos efeitos das alterações climáticas já sentidos nos oceanos, é crucial avaliar a capacidade de adaptação destas espécies e encontrar modelos híbridos que melhor nos permitam orientar medidas de gestão e conservação futuras

Climate change impacts on the distribution of coastal lobsters

Coastal lobsters support important fsheries all over the world, but there is evidence that climate-induced changes may jeopardize some stocks. Here we present the frst global forecasts of changes in coastal lobster species distribution under climate change, using an ensemble of ecological niche models (ENMs). Global changes in richness were projected for 125 coastal lobster species for the end of the century, using a stabilization scenario (4.5 RCP). We compared projected changes in diversity with lobster fsheries data and found that losses in suitable habitat for coastal lobster species were mainly projected in areas with high commercial fshing interest, with species projected to contract their climatic envelope between 40 and 100%. Higher losses of spiny lobsters are projected in the coasts of wider Caribbean/Brazil, eastern Africa and Indo-Pacifc region, areas with several directed fsheries and aquacultures, while clawed lobsters are projected to shifts their envelope to northern latitudes likely afecting the North European, North American and Canadian fsheries. Fisheries represent an important resource for local and global economies and understanding how they might be afected by climate change scenarios is paramount when developing specifc or regional management strategies.The Portuguese Foundation for Science and Technology (FCT) supported this study through a PhD grant (SFRH/BD/51514/2011) to JBP and a Senior Research Position (FCT Development Grant 2013) to RR. MBA acknowledges the Integrated Program of IC&DT Call no. 1/SAESCTN/ALENT-07-0224-FEDER-001755 for support of his research.Peer Reviewe

Climate change impacts on the distribution of coastal lobsters

Coastal lobsters support important fisheries all over the world, but there is evidence that climate-induced changes may jeopardize some stocks. Here we present the first global forecasts of changes incoastal lobster species distribution under climate change, using an ensemble of ecological niche models (ENMs). Global changes in richness were projected for 125 coastal lobster species for the end of the century, using a stabilization scenario (4.5 RCP). We compared projected changes in diversity with lobster fisheries data and found that losses in suitable habitat for coastal lobster species were mainly projected in areas with high commercial fishing interest, with species projected to contract their climatic envelope between 40 and 100%. Higher losses of spiny lobsters are projected in the coasts of wider Caribbean/Brazil, eastern Africa and Indo-Pacific region, areas with several directed fisheries and aquacultures, while clawed lobsters are projected to shifts their envelope to northern latitudes likely affecting the North European, North American and Canadian fisheries. Fisheries represent an important resource for local and global economies and understanding how they might be affected by climate change scenarios is paramount when developing specific or regional management strategies

Global Patterns of Coastal Cephalopod Diversity Under Climate Change

Coastal marine ecosystems are currently being exposed to climate change at a much faster rate than many other ecosystems, with coastal species being exposed to multiple stressors. Cephalopod mollusks play a pivotal role in marine trophic webs, and most are “keystone” species due to their influence on ecosystem dynamics. In this study, we characterized the global patterns of coastal cephalopod diversity and present, for the first time, a global forecast of potential changes in richness, mean body size, and assemblage composition (i.e., species replacement, nestedness, and combinations of both) for 161 coastal cephalopod species under climate change, using an ensemble of ecological niche models (ENMs) for an end of the century mitigation scenario. We have shown that, for the baseline period, coastal cephalopod diversity is higher in the Central Indo-Pacific area and that body size patterns follow the temperature-size rule, with larger animals occurring at higher latitudes. The end-century projections of habitat suitability show a different picture, with 96% of cephalopod species predicted to experience range contraction and 15% completely losing their environmental space. Nestedness is projected to be the main effect of species compositional change. Maximum body size is projected to increase in 44% of the pixels and decrease in 37%. Regarding fisheries, the projected changes are more favorable to the countries at higher latitudes, although the search for refugia of smaller tropical species might potentially lead to a mitigation of the negative effects of climate change in these areas, as measured by the total capture (ton). While the model has limitations, our findings reflect major climatic drivers of change and highlight the idea that even though cephalopod species seem good candidates to replace overexploited fish stocks in the near future, they may not have the environmental space to do so.This study was supported by the Portuguese Foundation for Science and Technology (FCT) through a Ph.D. grant (SFRH/BD/51514/2011) to JB-P, project grants PTDC/BIA-BEC/103266/2008 and PTDC/MAR/0908066/2008 to RR, and PTDC/AAC-AMB/98163/2008 to MA and FG.Peer reviewe

Spectral-Based Monitoring of Climate Effects on the Inter-Annual Variability of Different Plant Functional Types in Mediterranean Cork Oak Woodlands

Using remotely sensed data to estimate the biophysical properties of vegetation in woodlands is a challenging task due to their heterogeneous nature. The objective of this study was to assess the biophysical parameters of different vegetation types (cork oak trees, shrubs and herbaceous vegetation) in cork oak woodland through the analysis of temporal trends in spectral vegetation indices (VIs). A seven-year database (from 2011 until 2017) of in situ observations collected with a field spectroradiometer with a monthly basis was used and four VIs were derived, considered as proxies for several biophysical properties of vegetation such as biomass (Normalized Difference Vegetation Index—NDVI); chlorophyll content (MERIS Terrestrial Chlorophyll Index-MTCI), tissue water content (Normalized Difference Water Index—NDWI) and the carotenoid/chlorophyll ratio (Photochemical Reflectance Index—PRI). During the analyzed period, some key meteorological data (precipitation, temperature, relative air humidity and global radiation) were collected for the study site, aggregated at three different time-lags (short period (30 d), medium period (90 d) and hydrological period (HIDR)), and their relationship with VIs was analyzed. The results showed different trends for each vegetation index and vegetation type. In NDVI and NDWI, herbaceous vegetation showed a highly marked seasonal trend, whereas for MTCI, it was the cork oak and Cistus salvifolius, and for PRI, it was Ulex airensis that showed the marked seasonal trend. Shrubs have large differences depending on the species: the shallow-rooted Cistus salvifolius showed a higher seasonal variability than the deep-rooted Ulex airensis. Our results revealed the importance of temperature and precipitation as the main climatic variables influencing VI variability in the four studied vegetation types. This study sets up the relationships between climate and vegetation indices for each vegetation type. Spectral vegetation indices are useful tools for assessing the impact of climate on vegetation, because using these makes it easier to monitor the amount of “greenness”, biomass and water stress of vegetation than assessing the photosynthetic efficiency. Proximal remote sensing measurements are fundamental for the correct use of remote sensing in monitoring complex agroforest ecosystems, largely used to inform policies to improve resilience to drought, particularly in the Mediterranean region

Descending into the abyss: bathymetric patterns of diversity in decapod crustaceans shift with taxonomic level and life strategies

The aim of this study was to examine the depth-related changes in the diversity of decapod crustaceans from the intertidal to abyssal zones off Madeira Archipelago, a chain of islands in the subtropical North East Atlantic Ocean. The bathymetric gradient in species richness was evaluated using the reported ranges of 175 out of approximately 186 decapod species known in this archipelago. The depth-related changes at different taxonomic (order, sub-orders and families) and life strategy (pelagic, benthopelagic and benthic) levels were investigated and different ecological hypotheses (species-energy, mid-domain and Rapoport's effects) were tested to explain the observed patterns. No unimodal trend of Decapoda diversity was revealed and, instead, a monotonic decrease towards the abyss was observed, mainly as a consequence of the depth-related changes in the benthic diversity of the suborder Pleocyemata. Nonetheless, all bathymetric gradients of pelagic diversity (at order and suborder levels) displayed parabolic trends. There was also a general increase in bathymetric range towards greater depth, and the major faunal break was identified within the continental shelf area. All species richness–depth patterns were significantly nested, but there was a clear increasing trend in randomness from the benthic to the pelagic realm. The present study shows for the first time that even within the same taxonomic group and geographic region different bathymetric patterns of diversity can be observed, depending on the taxonomic level and, more importantly, on the group's life strategies. Moreover, our analysis supports the species-energy hypothesis, implicating a combination of temperature and food availability as the main causal predictors explaining diversity variation.publishe

Using Digital Photography to Track Understory Phenology in Mediterranean Cork Oak Woodlands

Monitoring vegetation is extremely relevant in the context of climate change, and digital repeat photography is a method that has gained momentum due to a low cost–benefit ratio. This work aims to demonstrate the possibility of using digital cameras instead of field spectroradiometers (FS) to track understory vegetation phenology in Mediterranean cork oak woodlands. A commercial camera was used to take monthly photographs that were processed with the Phenopix package to extract green chromatic coordinates (GCC). GCC showed good agreement with the normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) obtained with FS data. The herbaceous layer displayed a very good fit between GCC and NDVI (coefficient of determination, represented by r2 = 0.89). On the contrary, the GCC of shrubs (Cistus salviifolius and Ulex airensis) showed a better fit with NDWI (r2 = 0.78 and 0.55, respectively) than with NDVI (r2 = 0.60 and 0.30). Models show that grouping shrub species together improves the predictive results obtained with ulex but not with cistus. Concerning the relationship with climatic factors, all vegetation types showed a response to rainfall and temperature. Grasses and cistus showed similar responses to meteorological drivers, particularly mean maximum temperature (r = −0.66 and −0.63, respectively). The use of digital repeat photography to track vegetation phenology was found to be very suitable for understory vegetation with the exception of one shrub species. Thus, this method proves to have the potential to monitor a wide spectrum of understory vegetation at a much lower cost than FS

Impact of ocean warming on the early ontogeny of cephalopods: a metabolic approach

The impact of a realistic warming scenario on the metabolic physiology of early cephalopod (squid Loligo vulgaris and cuttlefish Sepia officinalis) life stages was investigated. During exposure to the warming conditions (19 °C for the western coast of Portugal in 2100), the increase in oxygen consumption rates throughout embryogenesis was much steeper in squid (28-fold increase) than in cuttlefish (11-fold increase). The elevated catabolic activity–accelerated oxygen depletion within egg capsules, which exacerbated metabolic suppression toward the end of embryogenesis. Squid late-stage embryos appear to be more impacted by warming via metabolic suppression than cuttlefish embryos. At all temperature scenarios, the transition from encapsulated embryos to planktonic paralarvae implied metabolic increments higher than 100 %. Contrary to the nektobenthic strategy of cuttlefish newborns, the planktonic squid paralarvae rely predominantly on pulsed jet locomotion that dramatically increases their energy requirements. In the future, hatchlings will require more food per unit body size and, thus, feeding intake success will be crucial, especially for squid with high metabolic rates and low levels of metabolic reserves

Ocean Warming Enhances Malformations, Premature Hatching, Metabolic Suppression and Oxidative Stress in the Early Life Stages of a Keystone Squid

<div><h3>Background</h3><p>The knowledge about the capacity of organisms’ early life stages to adapt to elevated temperatures is very limited but crucial to understand how marine biota will respond to global warming. Here we provide a comprehensive and integrated view of biological responses to future warming during the early ontogeny of a keystone invertebrate, the squid <em>Loligo vulgaris</em>.</p> <h3>Methodology/Principal Findings</h3><p>Recently-spawned egg masses were collected and reared until hatching at present day and projected near future (+2°C) temperatures, to investigate the ability of early stages to undergo thermal acclimation, namely phenotypic altering of morphological, behavioural, biochemical and physiological features. Our findings showed that under the projected near-future warming, the abiotic conditions inside the eggs promoted metabolic suppression, which was followed by premature hatching. Concomitantly, the less developed newborns showed greater incidence of malformations. After hatching, the metabolic burst associated with the transition from an encapsulated embryo to a planktonic stage increased linearly with temperature. However, the greater exposure to environmental stress by the hatchlings seemed to be compensated by physiological mechanisms that reduce the negative effects on fitness. Heat shock proteins (HSP70/HSC70) and antioxidant enzymes activities constituted an integrated stress response to ocean warming in hatchlings (but not in embryos).</p> <h3>Conclusions/Significance</h3><p>The stressful abiotic conditions inside eggs are expected to be aggravated under the projected near-future ocean warming, with deleterious effects on embryo survival and growth. Greater feeding challenges and the lower thermal tolerance limits of the hatchlings are strictly connected to high metabolic demands associated with the planktonic life strategy. Yet, we found some evidence that, in the future, the early stages might support higher energy demands by adjusting some cellular functional properties to increase their thermal tolerance windows.</p> </div