ABSTRACT
Artificial light at night (ALAN) is a recognized source of anthropogenic disturbance, although its effects on biological systems have not been fully explored. Within marine ecosystems, coastal areas are the most impacted by ALAN. Here, we focused on the Mediterranean sea urchin Paracentrotus lividus, which has a crucial role in shaping benthic ecosystems. Our objective was to investigate if ALAN affects the nocturnal locomotor behavior of P. lividus. A semi-controlled field study was conducted along a rocky shore near a promenade lit at night. Results suggested a potential impact of ALAN on the locomotor behavior of sea urchins. Individuals of P. lividus tended to move away from the light sources while its directions in dark conditions were uniform. Their locomotor performance, in presence of ALAN, was characterized by shorter latency time, lower sinuosity and higher mean speed at increasing light intensity, with potential cascading effect at the ecosystem level.
Subject(s)
Ecosystem , Light , Locomotion , Paracentrotus , Animals , Paracentrotus/physiology , Mediterranean Sea , Behavior, Animal , LightingABSTRACT
This paper studies the main factors affecting road traffic accidents (RTAs) using a systematic review. The primary focus is on factors related to road characteristics and driver behaviours. This review also addresses the socioeconomic and demographic factors to provide a clear overview of which groups suffer the most from RTAs. Several factors were found to affect RTAs, notably road characteristics: highways, high-speed roads, unplanned intersections and two-way roads without dividers; driver behaviours: reckless/aggressive driving and riding, excessive speeding, unawareness of traffic laws, and not using safety equipment; and vehicle types: four and two-wheeled. This review found that male and economically productive people with less education were mostly associated with RTAs. In addition, for most of the low and middle-income countries analyzed, there is a lack of quality data relating to RTAs. Nevertheless, this review provides researchers and policy makers with a better understanding of road accidents for improving road safety.
Subject(s)
Accidents, Traffic , Automobile Driving , Developing Countries , Accidents, Traffic/statistics & numerical data , Humans , Risk Factors , Socioeconomic Factors , Safety , Male , Environment DesignABSTRACT
The natural light cycle has profound effects on animals' cognitive systems. Its alteration owing to human activities, such as artificial light at night (ALAN), affects the biodiversity of mammalian and avian species by impairing their cognitive functions. The impact of ALAN on cognition, however, has not been investigated in aquatic species, in spite of the common occurrence of this pollution along water bodies. We exposed eggs of a teleost fish (the zebrafish Danio rerio) to ALAN and, upon hatching, we measured larvae' cognitive abilities with a habituation learning paradigm. Both control and ALAN-exposed larvae showed habituation learning, but the latter learned significantly slower, suggesting that under ALAN conditions, fish require many more events to acquire ecologically relevant information. We also found that individuals' learning performance significantly covaried with two behavioural traits in the control zebrafish, but ALAN disrupted one of these relationships. Additionally, ALAN resulted in an average increase in larval activity. Our results showed that both fish's cognitive abilities and related individual differences are negatively impacted by light pollution, even after a short exposure in the embryonic stage.
Subject(s)
Light , Zebrafish , Animals , Humans , Light Pollution , Larva , Behavior, Animal , MammalsABSTRACT
The globally widespread adoption of Artificial Light at Night (ALAN) began in the mid-20th century. Yet, it is only in the last decade that a renewed research focus has emerged into its impacts on ecological and biological processes in the marine environment that are guided by natural intensities, moon phase, natural light and dark cycles and daily light spectra alterations. The field has diversified rapidly from one restricted to impacts on a handful of vertebrates, to one in which impacts have been quantified across a broad array of marine and coastal habitats and species. Here, we review the current understanding of ALAN impacts in diverse marine ecosystems. The review presents the current state of knowledge across key marine and coastal ecosystems (sandy and rocky shores, coral reefs and pelagic) and taxa (birds and sea turtles), introducing how ALAN can mask seabird and sea turtle navigation, cause changes in animals predation patterns and failure of coral spawning synchronization, as well as inhibition of zooplankton Diel Vertical Migration. Mitigation measures are recommended, however, while strategies for mitigation were easily identified, barriers to implementation are poorly understood. Finally, we point out knowledge gaps that if addressed would aid in the prediction and mitigation of ALAN impacts in the marine realm.
Subject(s)
Anthozoa , Ecosystem , Animals , Coral Reefs , Light , Light PollutionABSTRACT
As road traffic accidents (RTAs) cause enormous economic and human losses, especially in developing countries, numerous research efforts are needed to identify the key risk factors that significantly influence accident and crash severity. Despite that Dhaka city is registering alarming rises in related deaths and severe injuries, Bangladesh has yet to collect significant RTAs data. Thus, this study adopts probit and Heckman selection probit models to investigate RTAs and injury severity levels using original data from an on-field survey collecting 786 participants' responses regarding their socio-economic and demographic characteristics, their knowledge of road traffic systems and rules, the roads and vehicles types, and the road infrastructure conditions. Probit model showed that the major risk factors that increase road accidents causing severe injuries were wrong-way driving, and lack of speed control signs and adequate street lights. RTAs resulting in severe injuries were significantly associated with being married, not having an educational degree, driving on highways and in city areas. Furthermore, the Heckman probit model's selection equation showed that respondents who were unaware of road accident risks, resided in rural areas, and with high household income had higher risks of being directly involved in RTAs.
Subject(s)
Automobile Driving , Wounds and Injuries , Accidents, Traffic , Bangladesh/epidemiology , Cities , Humans , Risk Factors , Wounds and Injuries/epidemiologyABSTRACT
The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus, initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness.
ABSTRACT
Comparing temporal patterns of distribution and abundance of target organisms between protected and harvested shores is essential to assess the extant effectiveness of marine protected areas (MPAs) and whether it is maintained through time. By means of an adapted Beyond-BACI approach, we compared the short- and long-term patterns of variation in the abundance of the sea urchin Paracentrotus lividus and the mussel Mytilus galloprovincialis at a protected shore (within the Parque Litoral Norte MPA, Portugal) and at three adjacent shores subject to intense harvesting over a decadal interval. Despite the existence of the MPA for more than 30 years, we did not obtain clear evidence of its persistent or recent effectiveness on intertidal species of commercial interest. We suggest the need for refining management options along the northern Portuguese coast, possibly by better enforcing current regulations and reconsidering the present design of protection schemes. Moreover, the adopted analytical approach may represent a methodological reference for similar investigations in systems where the perturbation of interest (protection or disturbance) would not occur at a given time during the course of the study, but has been operating since before the first sampling occasion and maintained until subsequent surveys.
Subject(s)
Bivalvia , Paracentrotus , Animals , Conservation of Natural Resources , Portugal , Sea Urchins , SeafoodABSTRACT
Understanding how increasing human domination of the biosphere affects life on earth is a critical research challenge. This task is facilitated by the increasing availability of open-source data repositories, which allow ecologists to address scientific questions at unprecedented spatial and temporal scales. Large datasets are mostly observational, so they may have limited ability to uncover causal relations among variables. Experiments are better suited at attributing causation, but they are often limited in scope. We propose hybrid datasets, resulting from the integration of observational with experimental data, as an approach to leverage the scope and ability to attribute causality in ecological studies. We show how the analysis of hybrid datasets with emerging techniques in time series analysis (Convergent Cross-mapping) and macroecology (Joint Species Distribution Models) can generate novel insights into causal effects of abiotic and biotic processes that would be difficult to achieve otherwise. We illustrate these principles with two case studies in marine ecosystems and discuss the potential to generalize across environments, species and ecological processes. If used wisely, the analysis of hybrid datasets may become the standard approach for research goals that seek causal explanations for large-scale ecological phenomena.
Subject(s)
Big Data , Ecosystem , Ecology , ResearchABSTRACT
Bioerosion and bioprotection (bio-remodeling) is the action exerted by biota colonizing rocky shores. It represents an important component among processes responsible for shaping coastal landforms, and a clear evidence of interaction between the biosphere and the solid earth. Barnacles extensively colonize the midlittoral belt of rocky shores in the Mediterranean Basin. Previous research, mostly based on laboratory evidence, suggests that barnacles are bioprotectors, in that they protect the rock surface from different types of physical and chemical weathering. In this paper, we present the results of a field experiment carried out at different spatial scales at two study areas along the moderately energetic and microtidal coast of NW Italy. Barnacles were removed from the sandstone bedrock in replicated plots (manipulated plots) arranged according to a hierarchical spatial design. After four months rock hardness was tested on each plot with both Schmidt hammer and Equotip Piccolo devices, as well as on a corresponding number of control plots. Data were processed by means of a multifactorial analysis of variance (ANOVA). In control plots, rock hardness tested with Schmidt hammer exceeded that measured in previously manipulated plots. Testing with Equotip yielded the opposite results. This experimental evidence confirmed that barnacles play a bio-protective role in the midlittoral at sub-surficial level, while adding the key aspect that this effect is generalizable to spatial scales ranging from a few centimeters up to tens of kilometers. In addition, our results showed, for the first time, that at surface level they can simultaneously act as bioeroders, likely causing corrosion of the rock surface by fostering dissolution of the sandstone carbonate matrix.
Subject(s)
Ecosystem , Thoracica , Animals , ItalyABSTRACT
Nutrient enrichment of coastal waters can enhance the invasibility and regrowth of non-native species. The invasive alga Caulerpa cylindracea has two distinct phases: a well-studied fast-growing summer phase, and a winter latent phase. To investigate the effects of nutrient enrichment on the regrowth of the seaweed after the winter resting-phase, a manipulative experiment was carried out in intertidal rockpools in the North-western Mediterranean. Nutrients were supplied under different temporal regimes: press (constant release from January to May), winter pulse (January to March) and spring pulse (March to May). Independently from the temporal characteristics of their addition, nutrients accelerated the re-growth of C. cylindracea after the winter die-back, resulting in increased percentage covers at the peak of the growing season. Nutrient addition did not influence the number and length of fronds and the biomass. Native components of the algal community did not respond to nutrient additions. Our results show that nutrient supply can favour the spread of C. cylindracea even when occurring at a time of the year at which the seaweed is not actively growing.
Subject(s)
Caulerpa/physiology , Seaweed/physiology , Water Pollutants, Chemical/analysis , Ecosystem , Environmental Monitoring , Nitrogen/analysis , Phosphorus/analysis , SeasonsABSTRACT
BACKGROUND: Organisms are facing increasing levels of environmental stress under climate change that may severely affect the functioning of biological systems at different levels of organization. Growing evidence suggests that reduction in body size is a universal response of organisms to global warming. However, a clear understanding of whether extreme climate events will impose selection directly on phenotypic plastic responses and how these responses affect ecological interactions has remained elusive. METHODS: We experimentally investigated the effects of extreme desiccation events on antioxidant defense mechanisms of a rocky intertidal gastropod (Patella ulyssiponensis), and evaluated how these effects scaled-up at the population and assemblage levels. RESULTS: With increasing levels of desiccation stress, limpets showed significant lower levels of total glutathione, tended to grow less and had reduced per capita interaction strength on their resources. DISCUSSION: Results suggested that phenotypic plasticity (i.e., reduction in adults' body size) allowed buffering biochemical responses to stress to scale-up at the assemblage level. Unveiling the linkages among different levels of biological organization is key to develop indicators that can anticipate large-scale ecological impacts of climate change.
ABSTRACT
PURPOSE: Anti Müllerian Hormone (AMH) has a negative and inhibitory role in many functions of human granulosa-lutein cells (hGCs) including notoriously the reduction of the aromatase CYP19A1 expression induced by follicle-stimulating hormone (FSH). No data have been provided on the possible role of AMH in modulating the response to luteinizing hormone (LH) (alone or combined with FSH) as well as its effect on other enzymes involved in steroidogenesis including aromatase P450scc. The aim of this study was to investigate the role of AMH as regulator of the basal and stimulated steroids production by hGCs. METHODS: Primary culture of hGCs were incubated with hormones AMH, LH, and FSH, alone or in combination. The CYP19A1 and P450scc messenger RNA (mRNA) expression, normalized by housekeeping ribosomal protein S7 (RpS7) gene, was evaluated by reverse transcriptase quantitative PCR (RT-qPCR). Each reaction was repeated in triplicate. Negative controls using corresponding amount of vehicle control for each hormone treatment were performed. RESULT: AMH did not modulate the basal mRNA expression of both aromatase genes at any of the concentrations tested. Meanwhile, the strong mRNA induction of CYP19A1 and P450scc generated by a 24-h gonadotropin treatment (alone and combined) was suppressed by 20 ng/ml AMH added to culture medium. CONCLUSIONS: These findings contribute in clarifying the relationship between hormones regulating the early phase of steroidogenesis confirming that AMH is playing a suppressive role on CYP19A1 expression stimulated by gonadotropin in hGCs. Furthermore, a similar inhibitory effect for AMH was observed on P450scc gene expression when activated by gonadotropin treatment.
Subject(s)
Anti-Mullerian Hormone/metabolism , Aromatase/biosynthesis , Cholesterol Side-Chain Cleavage Enzyme/biosynthesis , Granulosa Cells/metabolism , Anti-Mullerian Hormone/administration & dosage , Culture Media/chemistry , Estradiol/biosynthesis , Female , Follicle Stimulating Hormone/administration & dosage , Follicle Stimulating Hormone/metabolism , Gene Expression Regulation, Developmental/drug effects , Gonadotropins/administration & dosage , Granulosa Cells/drug effects , Humans , Luteinizing Hormone/administration & dosage , Luteinizing Hormone/metabolism , Primary Cell Culture , RNA, Messenger/biosynthesisABSTRACT
Ecosystems may shift abruptly between alternative states in response to environmental perturbations. Early warning indicators have been proposed to anticipate such regime shifts, but experimental field tests of their validity are rare. We exposed rocky intertidal algal canopies to a gradient of press perturbations and recorded the response of associated assemblages over 7 years. Reduced cover and biomass of algal canopies promoted the invasion of algal turfs, driving understory assemblages toward collapse upon total canopy removal. A dynamic model indicated the existence of a critical threshold separating the canopy- and turf-dominated states. We evaluated common indicators of regime shift as the system approached the threshold, including autocorrelation, SD, and skewness. These indicators captured changes in understory cover due to colonization of algal turfs. All indicators increased significantly as the system approached the critical threshold, in agreement with theoretical predictions. The performance of indicators changed when we superimposed a pulse disturbance on the press perturbation that amplified environmental noise. This treatment caused several experimental units to switch repeatedly between the canopy- and the turf-dominated state, resulting in a significant increase in overall variance of understory cover, a negligible effect on skewness and no effect on autocorrelation. Power analysis indicated that autocorrelation and SD were better suited at anticipating a regime shift under mild and strong fluctuations of the state variable, respectively. Our results suggest that regime shifts may be anticipated under a broad range of fluctuating conditions using the appropriate indicator.
Subject(s)
Ecosystem , Phaeophyceae/physiology , Seaweed/physiology , Biomass , Italy , Models, Biological , Population DynamicsABSTRACT
Explaining patterns of commonness and rarity is fundamental for understanding and managing biodiversity. Consequently, a key test of biodiversity theory has been how well ecological models reproduce empirical distributions of species abundances. However, ecological models with very different assumptions can predict similar species abundance distributions, whereas models with similar assumptions may generate very different predictions. This complicates inferring processes driving community structure from model fits to data. Here, we use an approximation that captures common features of "neutral" biodiversity models--which assume ecological equivalence of species--to test whether neutrality is consistent with patterns of commonness and rarity in the marine biosphere. We do this by analyzing 1,185 species abundance distributions from 14 marine ecosystems ranging from intertidal habitats to abyssal depths, and from the tropics to polar regions. Neutrality performs substantially worse than a classical nonneutral alternative: empirical data consistently show greater heterogeneity of species abundances than expected under neutrality. Poor performance of neutral theory is driven by its consistent inability to capture the dominance of the communities' most-abundant species. Previous tests showing poor performance of a neutral model for a particular system often have been followed by controversy about whether an alternative formulation of neutral theory could explain the data after all. However, our approach focuses on common features of neutral models, revealing discrepancies with a broad range of empirical abundance distributions. These findings highlight the need for biodiversity theory in which ecological differences among species, such as niche differences and demographic trade-offs, play a central role.
Subject(s)
Algorithms , Biodiversity , Marine Biology/methods , Models, Biological , Cold Climate , Geography , Population Density , Population Dynamics , Species Specificity , Tropical ClimateABSTRACT
Ecological tests of 1/f-noise models have advanced our understanding of how environmental fluctuations affect population abundance and species distributions. Most empirical studies have been conducted under controlled laboratory conditions and have focused on individual drivers. We present the results of a four-year field experiment in which canopy presence/absence and the availability of primary space were manipulated as red-noise and white-noise spatial processes, respectively, to evaluate their separate and compounded effects on algal turf distribution in a rocky intertidal community. Algal turfs closely tracked spatial variation in canopy distribution, displaying a reddened spectrum of spatial variation. Surprisingly, white-noise clearings also induced a red-shift in turf distribution, a pattern that was related to a nonlinear relation between gap size and turf colonization. The two disturbances interacted antagonistically, dampening the red-shift of turf distribution. Our results provide evidence of experimentally induced shifts in the spectrum of a spatial variable under natural environmental conditions.
Subject(s)
Ecosystem , Oceans and Seas , Phaeophyceae/physiology , Demography , Phaeophyceae/classificationABSTRACT
Understanding how species and environments respond to global anthropogenic disturbances is one of the greatest challenges for contemporary ecology. The ability to integrate modeling, correlative and experimental approaches within individual research programs will be key to address large-scale, long-term environmental problems. Scale-transition theory (STT) enables this level of integration, providing a powerful framework to link ecological patterns and processes across spatial and temporal scales. STT predicts the large-scale (e.g. regional) behavior of a system on the basis of nonlinear population models describing local (e.g. patch-scale) dynamics and the interaction between these nonlinearities and spatial variation in population abundance or environmental conditions. Here we use STT to predict the dynamics of turf-forming algae on rocky shores at Capraia Island, in the northwest Mediterranean. We developed a model of algal turf dynamics based on density-dependent growth that included the effects of local interactions with canopy algae. The model was parameterized with field data and used to scale up the dynamics of algal turfs from the plot scale (20×20 cm) to the island scale (tens of km). The interaction between nonlinear growth and spatial variance in cover of turfing algae emerged as a key term to translate the local dynamics up to the island scale. The model successfully predicted short-term and long-term mean values of turf cover estimated independently from a separate experiment. These results illustrate how STT can be used to identify the relevant mechanisms that drive large-scale changes in ecological communities. We argue that STT can contribute significantly to the connection between biomechanics and ecology, a synthesis that is at the core of the emerging field of ecomechanics.
Subject(s)
Ecosystem , Eukaryota/growth & development , Geologic Sediments , Models, Biological , Geography , Likelihood FunctionsABSTRACT
This study examined spatial relationships between rocky shore polychaete assemblages and environmental variables over broad geographical scales, using a database compiled within the Census of Marine Life NaGISA (Natural Geography In Shore Areas) research program. The database consisted of abundance measures of polychaetes classified at the genus and family levels for 74 and 93 sites, respectively, from nine geographic regions. We tested the general hypothesis that the set of environmental variables emerging as potentially important drivers of variation in polychaete assemblages depend on the spatial scale considered. Through Moran's eigenvector maps we indentified three submodels reflecting spatial relationships among sampling sites at intercontinental (>10,000 km), continental (1000-5000 km) and regional (20-500 km) scales. Using redundancy analysis we found that most environmental variables contributed to explain a large and significant proportion of variation of the intercontinental submodel both for genera and families (54% and 53%, respectively). A subset of these variables, organic pollution, inorganic pollution, primary productivity and nutrient contamination was also significantly related to spatial variation at the continental scale, explaining 25% and 32% of the variance at the genus and family levels, respectively. These variables should therefore be preferably considered when forecasting large-scale spatial patterns of polychaete assemblages in relation to ongoing or predicted changes in environmental conditions. None of the variables considered in this study were significantly related to the regional submodel.
Subject(s)
Ecosystem , Polychaeta/classification , Animals , Biodiversity , Environment , GeographyABSTRACT
Neutral models and differential responses of species to environmental heterogeneity offer complementary explanations of species abundance distribution and dynamics. Under what circumstances one model prevails over the other is still a matter of debate. We show that the decay of similarity over time in rocky seashore assemblages of algae and invertebrates sampled over a period of 16 years was consistent with the predictions of a stochastic model of ecological drift at time scales larger than 2 years, but not at time scales between 3 and 24 months when similarity was quantified with an index that reflected changes in abundance of rare species. A field experiment was performed to examine whether assemblages responded neutrally or non-neutrally to changes in temporal variance of disturbance. The experimental results did not reject neutrality, but identified a positive effect of intermediate levels of environmental heterogeneity on the abundance of rare species. This effect translated into a marked decrease in the characteristic time scale of species turnover, highlighting the role of rare species in driving assemblage dynamics in fluctuating environments.
Subject(s)
Ecosystem , Eukaryota/physiology , Algorithms , Animals , Biodiversity , Conservation of Natural Resources , Ecology , Environment , Eukaryota/genetics , Extinction, Biological , Models, Biological , Models, Statistical , Models, Theoretical , Population Density , Population Dynamics , Time FactorsABSTRACT
We evaluated a simplified algorithm for safely postponing diagnostic imaging for pulmonary embolism (PE). At the index visit, patients were identified as being at high or low risk of PE; the former received full dosage low molecular weight heparin while the latter were left untreated until performance of diagnostic imaging (max 72 hours). During this period, no thromboembolic events occurred in low-risk patients (0/211, 0.% [upper 95% CI 0.9%]); only one event occurred in those at high-risk (1/125, 0.8% [upper 95% CI, 1.2]). Our study demonstrates that diagnostic imaging for PE can be safely deferred for up to 3 days.
Subject(s)
Algorithms , Pulmonary Embolism/diagnosis , Adult , Aged , Aged, 80 and over , Anticoagulants/therapeutic use , Early Diagnosis , Female , Fibrin Fibrinogen Degradation Products/analysis , Hospitalization/statistics & numerical data , Humans , Male , Middle Aged , Predictive Value of Tests , Prevalence , Pulmonary Embolism/drug therapy , Risk , Thromboembolism/prevention & control , Thrombophilia/complications , Thrombophilia/diagnosis , Time Factors , Tomography, Spiral Computed , Treatment Outcome , Venous Thrombosis/prevention & control , Ventilation-Perfusion RatioABSTRACT
Extreme climate events produce simultaneous changes to the mean and to the variance of climatic variables over ecological time scales. While several studies have investigated how ecological systems respond to changes in mean values of climate variables, the combined effects of mean and variance are poorly understood. We examined the response of low-shore assemblages of algae and invertebrates of rocky seashores in the northwest Mediterranean to factorial manipulations of mean intensity and temporal variance of aerial exposure, a type of disturbance whose intensity and temporal patterning of occurrence are predicted to change with changing climate conditions. Effects of variance were often in the opposite direction of those elicited by changes in the mean. Increasing aerial exposure at regular intervals had negative effects both on diversity of assemblages and on percent cover of filamentous and coarsely branched algae, but greater temporal variance drastically reduced these effects. The opposite was observed for the abundance of barnacles and encrusting coralline algae, where high temporal variance of aerial exposure either reversed a positive effect of mean intensity (barnacles) or caused a negative effect that did not occur under low temporal variance (encrusting algae). These results provide the first experimental evidence that changes in mean intensity and temporal variance of climatic variables affect natural assemblages of species interactively, suggesting that high temporal variance may mitigate the ecological impacts of ongoing and predicted climate changes.