Natural Environmental Variability Research Articles

Reef fish identification through image records using artificial intelligence and convolutional neural network system

Coral reef environments show great diversity and abundance of species that represent important biological resources for obtaining food and medicines, in addition to acting as bioindicators of the quality of reef environments, serving as a parameter to diagnose environmental impacts and, simultaneously, to evaluate the availability and use of fishing stocks and biological resources in such environments. Monitoring such ecosystems arises from the urgent need to better understand the natural geographic and environmental variability of these systems, as well as their main drivers of change, to inform and promote more effective management of such environments. With the growing need to monitor communities of reef organisms, particularly fish, the creation of a digital analysis method would make a great contribution to the studies of reef fish. To fill this knowledge gap, our work evaluates the possibility of using an artificial intelligence mechanism using convolutional neural networks (CNN) to identify and count reef fish in image records, to optimize digital analysis of videos and/or photos in reef environments for fish ecology studies. The accuracy of the CNN identification method was effective, although it still has challenges to improve, such as: the need for a preliminary survey of reef fish species existing in the target area to be monitored, with the capture of good resolution images in different positions space for each species; production of an image bank with a large number of diverse images for each species (minimum of 200 images per species) and; To detect fish in videos, fast computers with a dedicated GPU card are needed, especially if the videos are high or ultra-resolution and have a large number of fps.

Ecological filtering shapes the impacts of agricultural deforestation on biodiversity.

The biodiversity impacts of agricultural deforestation vary widely across regions. Previous efforts to explain this variation have focused exclusively on the landscape features and management regimes of agricultural systems, neglecting the potentially critical role of ecological filtering in shaping deforestation tolerance of extant species assemblages at large geographical scales via selection for functional traits. Here we provide a large-scale test of this role using a global database of species abundance ratios between matched agricultural and native forest sites that comprises 71 avian assemblages reported in 44 primary studies, and a companion database of 10 functional traits for all 2,647 species involved. Using meta-analytic, phylogenetic and multivariate methods, we show that beyond agricultural features, filtering by the extent of natural environmental variability and the severity of historical anthropogenic deforestation shapes the varying deforestation impacts across species assemblages. For assemblages under greater environmental variability-proxied by drier and more seasonal climates under a greater disturbance regime-and longer deforestation histories, filtering has attenuated the negative impacts of current deforestation by selecting for functional traits linked to stronger deforestation tolerance. Our study provides a previously largely missing piece of knowledge in understanding and managing the biodiversity consequences of deforestation by agricultural deforestation.

Influence of flooding variability on the development of an Amazonian peatland

ABSTRACTPeat in the Pastaza–Marañón Foreland Basin (PMFB), northern Peru, forms beneath open wetlands, palm swamps, pole forests and seasonally flooded forests. These vegetation communities may represent different successional stages of peatlands, but the spatiotemporal patterns of peatland development in Amazonia are still poorly understood. We present a new geochemical and palaeoecological record spanning the last c. 4330 years from an open peatland (San Roque, core SAR_T3_03_B). Our results suggest the persistence of predominantly herbaceous vegetation communities at the core site since the start of peat accumulation (c. 3180 cal a bp). Micro‐X‐ray fluorescence core scanning provides evidence for episodes of fluvially derived minerogenic input and simultaneous increases in flood‐tolerant taxa relating to intervals of increased frequency and depth of riverine flooding. The establishment of Mauritia flexuosa palms from around 440 cal a bp coincided with a shift to lower flooding depth and frequency which continues to the present day. This study reveals the role of flooding variability in shaping peatland development and influencing vegetation succession in the PMFB, underlining the need to understand natural environmental variability for the conservation of these ecosystems due to their vital contributions to ecosystem services and carbon storage.

Managing Expectations from Intensively Monitored Watershed Studies

AbstractIntensively monitored watershed (IMW) studies, the intent of which is to quantify habitat restoration effects on salmonid populations, have been underway in the Pacific Northwest, USA, for more than two decades. Lack of population‐level response to habitat improvements by target species in some IMWs may be related to incomplete knowledge of factors regulating fish abundance, excessively prolonged restoration application periods, underappreciation of natural environmental and population variability, failure to carry out restoration at a sufficiently large scale within a watershed, lack of sufficient time to document a posttreatment response, or an actual failure of the restoration activities in those locations to achieve population recovery objectives. However, knowledge gained from IMWs has yielded important insight into (1) the long‐term responses of salmon and steelhead Oncorhynchus mykiss to different types of restoration and (2) the importance of placing freshwater habitat improvements in the context of changes in anadromous salmonid survival and growth during other life history stages. Scientists, funding organizations, and policymakers should appreciate the potential value of IMWs as long‐term barometers of the status of salmon populations and their habitats in watersheds where restoration activities are occurring. This requires a commitment to prolonged monitoring and an acknowledgment that environmental recovery after habitat restoration may take decades.

Periodic temporal environmental variations induce coexistence in resource competition models.

Natural ecosystems, in particular on the microbial scale, are inhabited by a large number of species. The population size of each species is affected by interactions of individuals with each other and by spatial and temporal changes in environmental conditions, such as resource abundance. Here, we use a generic population dynamics model to study how, and under what conditions, a periodic temporal environmental variation can alter an ecosystem's composition and biodiversity. We demonstrate that using timescale separation allows one to qualitatively predict the long-term population dynamics of interacting species in varying environments. We show that the notion of Tilman's R* rule, a well-known principle that applies for constant environments, can be extended to periodically varying environments if the timescale of environmental changes (e.g., seasonal variations) is much faster than the timescale of population growth (doubling time in bacteria). When these timescales are similar, our analysis shows that a varying environment deters the system from reaching a steady state, and stable coexistence between multiple species becomes possible. Our results posit that biodiversity can in part be attributed to natural environmental variations.

Deciphering the water quality impacts of COVID-19 human mobility shifts in estuaries surrounding New York City

The COVID-19 pandemic altered human mobility, particularly in large metropolitan areas. In New York City (NYC), stay-at-home orders and social distancing led to significant decreases in commuting, tourism, and a surge of outward migration. Such changes could result in decreased anthropogenic pressure on local environments. Several studies have linked COVID-19 shutdowns with improvements in water quality. However, the bulk of these studies primarily focused on short-term impacts during shutdown periods, without assessing longer-term impacts as restrictions eased. Here, we examine both concurrent lockdown and societal reopening impacts on water quality, using pre-pandemic baseline conditions, in two highly urbanized estuaries surrounding NYC, the New-York Harbor estuary and Long Island Sound (LIS). We compiled datasets from 2017 to 2021 of mass-transit ridership, work-from-home trends, and municipal wastewater effluent to assess changes in human mobility and anthropogenic pressure during multiple waves of the pandemic in 2020 and 2021. These were linked to changes in water quality assessed using high spatiotemporal ocean color remote sensing, which provides near-daily observations across the estuary study regions. To distinguish anthropogenic impacts from natural environmental variability, we examined meteorological/hydrological conditions, primarily precipitation and wind. Our results show that nitrogen loading into the New York Harbor declined significantly in the spring of 2020 and remained below pre-pandemic values through 2021. In contrast, nitrogen loading into LIS remained closer to the pre-pandemic average. In response, water clarity in New-York Harbor significantly improved, with less of a change in LIS. We further show that changes in nitrogen loading had higher impact on water quality than meteorological conditions. Our study demonstrates the value of remote sensing observations in assessing water quality changes when field-based monitoring is hindered and highlights the complex nature of urban estuaries and their heterogeneous response to changes in extreme events and human behavior.

Environmental and genetic variation in an asexual plant

Species may respond to variation in environmental conditions by modifying their phenotype to match local levels of resource availability. This phenotypic response can be driven by plastic physiological change, or by adaptive genetic change. Here we use Lemna minor (lesser duckweed), a small aquatic macrophyte that is increasingly used as a model in ecology and evolution, to investigate the source and maintenance of phenotypic variation in natural environments. We found substantial phenotypic variation in L. minor in the field, with its frond area and root length changing predictably over natural environmental gradients of resource availability. Separating environmental and genetic variation in these traits in a common garden, we attribute the majority of phenotypic variation we observed in the field to phenotypic plasticity. Despite this, there was substantial within-site genetic variation. We found evidence of strong purifying selection in the field, that is necessarily balanced by mutation and migration. Using measures of environmental and genetic variation in phenotype and fitness, we estimate the rates of dispersal and evolution of fitness necessary to sustain the observed levels of genetic variation.

Effects of environment and metacommunity delineation on multiple dimensions of stream fish beta diversity

IntroductionBeta diversity represents changes in community composition among locations across a landscape. While the effects of human activities on beta diversity are becoming clearer, few studies have considered human effects on the three dimensions of beta diversity: taxonomic, functional, and phylogenetic. Including anthropogenic factors and multiple dimensions of biodiversity may explain additional variation in stream fish beta diversity, providing new insight into how metacommunities are structured within different spatial delineations.MethodsIn this study, we used a 350 site stream fish abundance dataset from South Carolina, United States to quantify beta diversity explainable by spatial, natural environmental, and anthropogenic variables. We investigated three spatial delineations: (1) a single whole-state metacommunity delineated by political boundaries, (2) two metacommunities delineated by a natural geomorphic break separating uplands from lowlands, and (3) four metacommunities delineated by natural watershed boundaries. Within each metacommunity we calculated taxonomic, functional, and phylogenetic beta diversity and used variation partitioning to quantify spatial, natural environmental, and anthropogenic contributions to variations in beta diversity.ResultsWe explained 25–81% of the variation in stream fish beta diversity. The importance of these three factors in structuring metacommunities differed among the diversity dimensions, providing complementary perspectives on the processes shaping beta diversity in fish communities. The effect of spatial, natural environmental, and anthropogenic factors varied among the spatial delineations, which indicate conclusions drawn from variation partitioning may depend on the spatial delineation chosen by researchers.DiscussionOur study highlights the importance of considering human effects on metacommunity structure, quantifying multiple dimensions of beta diversity, and careful consideration of user-defined metacommunity boundaries in beta diversity analyses.

The influence of sociodemographic and environmental factors on wildlife carcass submissions in urban areas: Opportunities for increasing equitable and representative wildlife health surveillance

Wildlife health surveillance is important in rapidly expanding urban areas, where wildlife live in close association with humans and face unique health risks. Urban areas are not homogeneous, and social and environmental factors may affect the distribution of surveillance data we receive from these environments. The Canadian Wildlife Health Cooperative (CWHC) operates a national wildlife surveillance programme that receives carcass submissions for diagnostic evaluation. Our objective was to evaluate sociodemographic and environmental factors associated with CWHC submissions within two cities in Ontario, Canada. Submissions were mapped at two geographic scales and linked with census and environmental data. The results of mixed multivariable Poisson and negative binomial regression analyses suggest that natural (e.g., percent parkland) and anthropogenic environmental (e.g., presence of a zoo) and social variables (e.g., low income) are associated with submissions at both administratively relevant scales. Associations that are common across scales may represent robust intervention points and inform surveillance methodology/messaging. Surveillance data may influence public health policy, wildlife management, and other decision-making regarding the benefits/risks associated with coexistence with wildlife. This study highlights gaps in surveillance methodology that may prevent equal opportunity for participation in wildlife health surveillance and enable equal opportunity to benefit from the associated outputs.

Seasonal and interannual changes in a coastal Antarctic zooplankton community

Seasonal fluctuations are key features of high-latitude marine ecosystems, where zooplankton exhibit a wide array of adaptations within their life cycles. Repeated, sub-seasonal sampling of Antarctic zooplankton is rare, even along the West Antarctic Peninsula (WAP), where multidecadal changes in sea ice and phytoplankton are well documented. We quantified zooplankton biomass, size structure, and composition at 2 coastal time-series stations in the northern WAP over 3 field seasons (November-March) with different sea-ice, temperature, and phytoplankton conditions. Seasonal peaks in zooplankton biomass followed weeks after phytoplankton blooms. Biomass of mesozooplankton (0.2-2 mm) was consistent and low, while high biomass of macrozooplankton (>2 mm) occasionally resulted in a size distribution dominated by krill and salps, which appears to be a characteristic phenomenon of the Southern Ocean. Zooplankton composition and size changed between years and from spring to summer as the water column warmed after sea-ice breakup. Seasonal succession was apparent typically in decreasing zooplankton size and a shift to species that are less dependent upon phytoplankton. Mean central abundance dates varied by 54 d across 14 taxa, and specific feeding preferences and life-history traits explained the different seasonal abundance patterns. In all 3 yr, the dominant euphausiid species switched from Euphausia superba in spring to Thysanoessa macrura in late summer. Various taxa shifted their phenology between years in response to the timing of sea-ice breakup and the onset of phytoplankton productivity, a level of natural environmental variability to which they appear resilient. Nevertheless, the limits to this resilience in response to climate change remain uncertain.

Equilibrium or imbalance? Regional variations and evolutionary traits of two-way FDI coordination level in Yangtze River economic belt

Based on the VAR model, the two-way FDI data of the Yangtze River Economic Zone from 2005 to 2019 were used as the specimen. The correlation of the two-way FDI was observed using the VAR impulse effect through ADF root test and lag structure laboratory testing. The original study results demonstrated that there have been disparities in the spatial and temporal evolution of FDI and OFDI coordination levels between the eastern, central, and western city groups in the Yangtze River Economic Belt region from 2005 to 2019. The unequal expansion of FDI and OFDI is the phenomena that results in the gap between eastern and western cities. The development of the coupling coordination level between the east and west areas has been unequal due to variances in the natural environment, trade value, corporate expansion, and other variables. Contrarily, the Yangtze River Economic Belt’s western urban agglomerations have a lower level of coupling and coordination development than the region’s eastern urban agglomerations, with an overall declining phenomena from east to west. The coupling and coordinated development of two-way FDI within the economic belt, which has a significant impact on the rationalization of regional resource allocation, industrial structure optimization, and technology iteration with civilization construction, can be greatly facilitated, in our opinion, by strengthening uncoordinated regional development infrastructure and deepening regional economic-industrial links.

Contribution of the seagrass Syringodium isoetifolium to the metabolic functioning of a tropical reef lagoon

Seagrasses are gaining attention thanks to their metabolism and potential major role as carbon sinks, with further implications as nature-based solutions against climate change. Despite their recognized importance and the growing number of studies published, there is still a striking paucity of information on seagrass metabolism and contribution to biogeochemical cycles for some seagrass species and ocean areas. In this study we assessed the metabolic balance and nutrient cycling contribution of seagrasses to the benthic compartment of a tropical reef lagoon in Reunion Island, providing original information on a barely studied seagrass species (Syringodium isoetifolium) and a poorly studied ocean region (West Indian Ocean). We measured the net productivity, respiration and the metabolic balance in different components of the lagoon benthic compartment (i.e. seagrass, sediment, and benthic community) and the water-sediment nutrient benthic fluxes at differently impacted sites within the lagoon. The biogeochemical environmental variability, including inorganic and organic indicators of anthropogenic contamination, was also assessed at each site.Large spatial variability was detected in the metabolic balance of each benthic component assessed, also associated with the natural and/or anthropic-driven environmental variability found in the lagoon. The seagrass S. isoetifolium was net autotrophic across the lagoon and contributed to the lagoon benthic metabolism with net plant productivity exceeding by one order of magnitude the plant respiration. The lowest seagrass metabolism was detected at the impacted site. The metabolic balance of the sediment was heterotrophic but the high productivity of S. isoetifolium contributed to reducing the heterotrophy of the whole benthic community. The lagoon-wide benthic metabolic balance was slightly heterotrophic, but the associated uncertainty ranged from autotrophy to heterotrophy. Nutrient concentrations in the lagoon were low and the benthic community capacity for nutrient retention (uptake) and removal (denitrification and anammox) indicated potential for buffering moderate nutrient inputs into the lagoon. Organic contaminants of emerging concern (CECs) were low but detectable in the lagoon, especially in highly frequented beach areas, arising as an environmental quality indicator of interest.

Natural Environmental Variation Determines Microbial Diversity Patterns in Serofluid Dish, a Traditional Chinese Fermented Vegetable Food.

Serofluid dish is a traditional fermented food that contains rich microbial populations. To gain insight into the environmental variables shaping the microbial diversity patterns, serofluid dish samples were collected from different areas, and 16S rRNA sequencing was performed. Analyses revealed both species and community diversity, including phylotype richness, Shannon index and phylogenetic diversity, were mostly influenced by pH. Additionally, such effects were corroborated by the Mantel test of pairwise UniFrac distances and variable selection of multiple linear regression models. Eventually, correlations between dominant lineages and the pH of serofluid dish other than geographical distance explained a large portion of the changes in microbial composition and diversity. Lactobacillus and related genera, Pediococcus and Acetobacter were largely driven by the variability of pH, and higher richness was observed under moderate pH ranges. Collectively, the results demonstrated that a microbial diversity pattern in serofluid dish is predictable by natural environmental variation and can be better understood through pH conditions.

Upwelling-level acidification and pH/pCO2 variability moderate effects of ocean acidification on brain gene expression in the temperate surfperch, Embiotoca jacksoni.

Acidification‐induced changes in neurological function have been documented in several tropical marine fishes. Here, we investigate whether similar patterns of neurological impacts are observed in a temperate Pacific fish that naturally experiences regular and often large shifts in environmental pH/pCO2. In two laboratory experiments, we tested the effect of acidification, as well as pH/pCO2 variability, on gene expression in the brain tissue of a common temperate kelp forest/estuarine fish, Embiotoca jacksoni. Experiment 1 employed static pH treatments (target pH = 7.85/7.30), while Experiment 2 incorporated two variable treatments that oscillated around corresponding static treatments with the same mean (target pH = 7.85/7.70) in an eight‐day cycle (amplitude ± 0.15). We found that patterns of global gene expression differed across pH level treatments. Additionally, we identified differential expression of specific genes and enrichment of specific gene sets (GSEA) in comparisons of static pH treatments and in comparisons of static and variable pH treatments of the same mean pH. Importantly, we found that pH/pCO2 variability decreased the number of differentially expressed genes detected between high and low pH treatments, and that interindividual variability in gene expression was greater in variable treatments than static treatments. These results provide important confirmation of neurological impacts of acidification in a temperate fish species and, critically, that natural environmental variability may mediate the impacts of ocean acidification.

The effects of blue and red light color combinations on the growth and immune performance of juvenile steelhead trout, Oncorhynchus mykiss

To examine the growth and immune response of steelhead trout (Oncorhynchus mykiss) under conditions of differing light color, we investigated the effects of different red and blue light color combinations on plasma non-specific immunity, hepatic antioxidant capacity, and GH/IGF-1 axis gene expression in juvenile steelhead trout (initial weight: 34.67 ± 2.69 g). The 16-week trial was set up with six treatments in which light color varied at a constant light intensity of 150 lx: 12 h white light + 12 h dark (12 W), 12 h blue light + 12 h dark (12B), 12 h red light + 12 h dark (12 R), 1.5 h blue light + 9 h red light + 1.5 h blue light + 12 h dark (3B9R), 3 h blue light + 6 h red light + 3 h blue light + 12 h dark (6B6R), total 12 h of blue and red light + 12 h dark (T12BR). The results revealed that the 12B and 3B9R light environments significantly enhanced plasma immunoglobulin M levels in steelhead trout, and that the 3B9R light environment also promoted significant increases in the gene expression of hepatic growth hormone receptor, insulin-like growth factor 1, and insulin-like growth factor-binding protein. The 3B9R light environment was also found enhance the antioxidant capacity of trout by increasing hepatic superoxide dismutase, catalase, and glutathione peroxidase activities. In contrast, trout exposed to the 6B6R light environment showed significant reductions in growth and immune performance, and there were similar reductions in hepatic antioxidant capacity. Furthermore, fish exposed to the 12R light environment were found to be characterized by elevated levels of lipid peroxidation and malondialdehyde, which are indicative of hepatic stress. In addition, we observed that in response to light variation, there were elevations in the activities of glutamic oxaloacetic transaminase and lactic dehydrogenase in the plasma of steelhead trout, thereby indicating an inhibition of cardiomyocyte function. In summary, our findings indicate that a 3B9R light environment simulates the blue-red-blue daily rhythm of light color variation in natural underwater environments, which is beneficial with respect to enhancing the growth and immunity of steelhead trout, and could accordingly be used to provide suitable light conditions in commercial trout production. However, sudden changes in light color should be avoided in the aquaculture of trout.

The Pattern and Local Push Factors of Rural Depopulation in Less-Developed Areas: A Case Study in the Mountains of North Hebei Province, China.

Rural depopulation is the most significant geographical phenomenon in rural areas during the process of urbanization. Although many studies have investigated the driving force of rural depopulation based on rural-urban migration at the macro level, the local factors, and their impact on rural depopulation from the rural areas have been not fully revealed. This paper selected the northern mountains of China’s Hebei province as a study area to explore the pattern and local push factors of rural depopulation at the rural-township levels based on GeoDetector. The main findings are summarized as follows. (1) Rural depopulation varies substantially, demonstrates spatial correlation, and is distributed in clusters. From a dynamic perspective, compare that in years 2000–2010, the population growth areas during 2010–2017 have been significantly expanded, while the sharp depopulation areas and severe depopulation areas experienced shrinkage in our study area. (2) The pattern of rural depopulation is in accordance with terrain. Rural depopulation tends to be stronger in plateaus and mountains, while relatively milder in intermontane basins, hills, and piedmont plains. (3) The agricultural suitability of natural environmental and rural economic opportunities together with climate changes were the most important driving forces of rural depopulation at local levels. Location, sparse population, and inadequate public services also contributed to rural depopulation. However, the dominant driving factors are different in the different periods. Rural depopulation was mainly driven by arable land per capita and natural environmental variables in the years 2000–2010, while the population density, location, and off-farm economic opportunities played a decisive role in the years 2010–2017. (4) Rural depopulation is a complex, multi-dimensional process driven by a combination of multiple factors including different environmental factors, economic opportunities, and location. This paper reveals the push factors of rural depopulation in underdeveloped mountainous areas by a quantitative empirical approach, inspiring increased attention to the impacts of local factors and spatial correlations on rural depopulation, and has many implications for the policy design of China’s rural revitalization.

Socio-Ecological Effects on the Patterns of Non-native Plant Distributions on Hainan Island

Non-native plants spread to recipient areas via natural or human-mediated modes of dispersal, and, if the non-native species are invasive, introduction potentially causes impacts on native plants and local ecosystems as well as economic losses. Therefore, we studied the diversity and distributional patterns of non-native plant species diversity in the tropical island province of Hainan, China and its relationships with environmental and socioeconomic factors by generating a checklist of species and subsequently performing an analysis of phylogenetic diversity. To generate the checklist, we began with the available, relevant literature representing 19 administrative units of Hainan and determined the casual, naturalized, or invasive status of each species by conducting field surveys within 14 administrative units. We found that non-native plants of Hainan comprise 77 casual species, 42 naturalized species, and 63 invasive species. Moreover, we found that non-native plant species had diverse origins from North and South America, Africa, and Asia and that the most common species across administrative areas belong to the plant families Asteraceae and Fabaceae. Moreover, the numbers of non-native species distributed in the areas of Hainan bording the coast arer greater than those within interior areas of the province. Among the coastal areas, Haikou has the highest species richness and, simultaneously, the highest values for significantly, positively correlated predictor variables, population and GDP (R2 = 0.60, P < 0.01; R2 = 0.64, P < 0.01, respectively). In contrast, the landlocked administrative units of Tunchang and Ding’an have the smallest number of non-native species, while their populations are less than a quarter of that of Haikou and their GDP less than one tenth. Among natural environmental variables, we determined that the number of non-native species had the strongest correlation with the minimum temperature in the coldest month, which predicts a smaller number of non-native species. Additionally, non-native species are primarily distributed in urban and rural built-up areas and agricultural areas; areas that are dominated by human activities. Overall, our study provides a working checklist of the non-native plants of Hainan as well as a theoretical framework and reference for the control of invasive plants of the province.

Combining satellite geophysical data with continuous on-site measurements for monitoring the dynamic parameters of civil structures

One key issue in the Structural Health Monitoring (SHM) of buildings is the influence of the soil on the dynamics of the system. The lack of accurate information on soil-structure interaction represents a source of significant uncertainty and generates difficulties in assessing the state of structural health. In this respect, satellite data could represent a valuable tool for soil knowledge. This paper presents the first study of satellite data coming from the environmental Copernicus program of the European Space Agency (ESA) for the alternative application in the field of SHM. In particular, Land Surface Temperature (LST) and Soil Water Index (SWI) data are elected to study surface temperature and moisture condition of the soil. Once examined and processed, these records have been statistically analyzed, crossed with on-site experimental quantities (natural frequencies and environmental variations), and given as input to a Finite Element (FE) model. The final goal is to understand the actual structural behavior, but also to monitor the evolution of the dynamic parameters for the purposes of structural and seismic monitoring. The largest oval masonry dome in the world was chosen as a prominent case study to demonstrate this novel approach to SHM.

Hyperspectral characterization of natural lighting environments.

Lights are primary drivers of some crucial biological functions including vision and regulation of circadian rhythm. To understand the light exposure pattern that we experience in a daily life, many past studies measured the spectral composition of natural daylight and artificial lighting. The aim of this book chapter is to introduce a novel method to characterize directional spectral variation in natural lighting environments. An omnidirectional hyperspectral illumination map stores the spectra of lights coming from every direction toward a single point in a scene. Such illumination maps allow us to simulate a spatial light exposure pattern that reaches our eyes, providing useful resources to research areas such as chronobiology, vision science and any other fields which benefit from knowledge about the spectral nature of visual lighting environments.

Variability in grazing on juvenile giant kelp throughout an upwelling season

Upwelling provides high amounts of nutrients that support primary production in coastal habitats, including giant kelp Macrocystis pyrifera forests. Growth and recruitment of kelp forests are controlled by environmental conditions, including temperature, nutrient availability, and storms, as well as biotic interactions. However, our understanding of juvenile persistence in the field is extremely limited, particularly the effects of grazing on the survival of early kelp stages and how environmental variability associated with upwelling dynamics may modulate grazing effects. We quantified herbivore impacts on juvenile M. pyrifera by deploying thirteen 24 h caging experiments approximately every 2 wk throughout the upwelling season in a giant kelp forest in Monterey Bay, CA, USA. Experiments spanned a range of natural environmental variation in oxygen, pH, and temperature, conditions known to affect grazer physiology and that are projected to become more extreme under global climate change. Overall, the herbivore community had a large effect on kelp survival, with 68.5% of juvenile kelp removed on average across experiments. Grazing increased throughout the season, which was most strongly correlated with decreasing monthly oxygen variance and weakly correlated with decreasing monthly pH variance and increasing temperature. This suggests that large swings in oxygen during peak kelp recruitment in spring may provide a temporal refuge from grazing, allowing kelp to reach larger sizes by late summer and fall when upwelling has relaxed. This study highlights the potential of current environmental variability, and its predicted increase under future scenarios, to mediate species interactions and habitat persistence.