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Tree height, growth rate and stand density determined by ALS drive probability of Scots pine mortality

ECOLOGICAL INDICATORS 2022年 145卷

作者： Tyminska-Czabanska, Luiza Hawrylo, Pawel Janiec, Piotr Socha, Jaroslaw Agr Univ Krakow Fac Forestry Dept Forest Resources Management Al 29 Listopada 46 PL-31425 Krakow Poland Adam Mickiewicz Univ Inst Geoecol & Geoinformat Poznan Poland Forest Management & Geodesy Bur Sekocin Stary Poland

Understanding how particular stand factors shape patterns of forest mortality is crucial for supporting forest management as well as creating appropriate adaptation strategies in the era of climate change. Until recently, many stand characteristics such as tree height, height increment, and stand density were measured by traditional field methods. However, the current use of remote sensing tools opens up new possibilities for forest monitoring and measurements. Thus, the research objective was to assess the influence of selected tree and forest variables measurable by ALS-top height, top height increment, and stand density-on the probability of Scots pine stands' mortality. We focus on the Katowice region in southern Poland, which experienced extensive drought -induced mortality in 2015-2021. For this area, we acquired data from two ALS acquisitions to determine the stand top height, top height increment, and stand density. We found that the probability of tree mortality is most strongly driven by stand height and height growth rate. Moreover, the highest probability of mortality was observed in the densest stands. Through the identification of a core set of stand characteristics that predispose forests to mortality, this work can inform future research on forest structure under accelerated mortality. Bitemporal ALS allows for a brief overview of height increment trends over large regions. Therefore, detecting trends in height increment using ALS can help us assess vulnerability to disturbance and provide an effective approach for early detection of tree stress and mortality signs.

关键词： Tree mortality Climate change LIDAR generalized additive models Temperate forests

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Long-term effects of sheep-grazing and its removal on vegetation dynamics of British upland grasslands and moorlands;local management cannot overcome large-scale trends

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ECOLOGICAL INDICATORS 2022年 139卷

作者： Alday, Josu G. Reilly, John O. Rose, Rob J. Marrs, Rob H. Univ Liverpool Sch Environm Sci Liverpool L69 3GP Lancs England Joint Res Unit CTFC AGROTECNIO Ave Alcalde Rovira Roure 191 Lleida E25198 Spain Univ Lleida Dept Crop & Forest Sci Ave Alcalde Rovira Roure 191 Lleida E25198 Spain Railway Cottages Ptyxis Ecol Lambley CA8 7LL Northb England Ctr Ecol & Hydrol UKCEH Lancaster Bailrigg Lancaster LA1 4AP Lancs England

The upland and mountainous regions of northern Europe provide a wide variety of ecosystem services. However, these ecosystem services are highly vulnerable to environmental and land-use change. To ensure their future conservation, it is therefore, essential to understand whether upland plant communities will respond positively or negatively to a range of environmental factors such as grazing pressure and landscape-scale factors such as changes in atmospheric SO2 and NOx deposition. To understand this, here, we describe the long-term trends in four UK upland communities (high-level grassland, intermediate grassland, blanket bog, high-level bog) using four replicated long-term experiments examining the effects of sheep grazing compared to no-sheep grazing in Moor House (from 1954 to 2016). Our results showed that species richness and abundance recovered in grazed plots after 2000, with improvements in species richness and abundance of vascular plants, mosses, and liverworts. Unfortunately, no improvement was found for lichens. Species richness, vascular plants, and mosses recovered the fastest, and much faster than liverworts. There was no evidence of slower recovery of species richness and abundance in plots where sheep grazing was removed. These results are consistent with longitudinal studies suggesting recovery after 2000 as a result of reduced atmospheric deposition. Although trends in diversity and abundance in the grazed and ungrazed plots were not identical, they were not markedly different either. The similar richness and abundance trends in the grazed and ungrazed plots found in each plant community suggest that within-community dynamics may overcome initial differences between the grazing treatments over time. In contrast, differences in richness and abundance among plant communities over time suggest that some landscape-scale trends, such as those caused by a reduction in nutrient inputs, initiate community-dependent recovery.

关键词： Moorland Blanket bog generalized additive models Sheep grazing Sheep exclosures

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Historical variations of sedimentary organic matter sources and their relationships with human socio-economic activities in multiple habitats of a shallow lake

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ECOLOGICAL INDICATORS 2022年 140卷

作者： Yin, Zheng Li, Liqing Liu, Chenyu Yan, Weijin Wang, Lai Zhang, Meiyi Wang, Dongsheng Chinese Acad Sci Res Ctr Ecoenvironm Sci State Key Lab Environm Aquat Chem Beijing 100085 Peoples R China Chinese Acad Sci Res Ctr Ecoenvironm Sci Yangtze River Delta Sub Ctr Yiwu City 322000 Zhejiang Peoples R China China Univ Geosci Sch Environm Studies Wuhan 430074 Peoples R China Zhejiang Univ Coll Environm & Resource Sci Hangzhou 310058 Peoples R China China Univ Geosci Fac Mat Sci & Chem Wuhan 430074 Peoples R China Chinese Acad Sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China Energy Conservat & Environm Protect Co Ltd State Key Lab Iron & Steel Ind Environm Protect Beijing 100088 Peoples R China

Understanding the source and historical variation of sedimentary organic matter (OM) and their relationships with human socio-economic activities is of great significance to water resource management. In this work, sediment cores from five different habitats were collected in Baiyangdian Lake, China. A Bayesian model (stable isotope analysis in R, SIAR) was utilized to apportion the historical changes of the proportional contributions of potential sources in sediments based on carbon and nitrogen stable isotopes (813C and 815N) and C/N ratios. The impacts of human socio-economic activity factors (GDP, population) on the historical variations of sedimentary OM source have been evaluated by the generalized additive models (GAMs). The results showed that autochthonous OM (phytoplankton) was the dominant sediment OM source in river course (13%-48%), lotus pond (16%-48%) and open water (16%-47%), and the contributions began to increase after 1944, 1950 and 1962, respectively. Phytoplankton (37%-53%) was also the main source of OM in sediments of fish pond, but its contribution had remained high throughout. Allochthonous OM (soil OM: 29%-42%) was the main source of sedimentary OM in reed marshes, and it showed a slow increasing trend after 1995. The GAMs results showed that population was the dominant contributor to the variations of OM sources in sediments of lotus pond, open water and fish pond and GDP was the dominant contributor to that in sediments of reed marshes, with the interpretation rates of 70%-99%. Both GDP and population were dominant influence factors on sedimentary OM sources of river course, which account for 52%-98%. It is proved that human socio-economic activities have significant impact on the historical variations of sedimentary OM sources.

关键词： Sediment Organic matter Eutrophication generalized additive models Baiyangdian Lake

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Bootstrapping Recommendations at Chrome Web Store 21

Bootstrapping Recommendations at Chrome Web Store

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27th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD)

作者： Qin, Zhen Zhuang, Honglei Jagerman, Rolf Qian, Xinyu Hu, Po Chen, Dan Chary Wang, Xuanhui Bendersky, Michael Najork, Marc Google Inc Mountain View CA 94043 USA

ISBN: (纸本)9781450383325

Google Chrome, one of the world's most popular web browsers, features an extension framework allowing third-party developers to enhance Chrome's functionality. Chrome extensions are distributed through the Chrome Web Store (CWS), a Google-operated online marketplace. In this paper, we describe how we developed and deployed three recommender systems for discovering relevant extensions in CWS, namely non-personalized recommendations, related extension recommendations, and personalized recommendations. Unlike most existing papers that focus on novel algorithms, this paper focuses on sharing practical experiences when building large-scale recommender systems under various real-world constraints, such as privacy constraints, data sparsity and skewness issues, and product design choices (e.g., user interface). We show how these constraints make standard approaches difficult to succeed in practice. We share success stories that turn negative live metrics to positive ones, including: 1) how we use interpretable neural models to bootstrap the systems, help identifying pipeline issues, and pave the way for more advanced models;2) a new item-item based algorithm for related recommendations that works under highly skewed data distributions;and 3) how the previous two techniques can help bootstrapping the personalized recommendations, which significantly reduces development cycles and bypasses various real-world difficulties. All the explorations in this work are verified in live traffic on millions of users. We believe that the findings in this paper can help practitioners to build better large-scale recommender systems.

关键词： recommender systems learning to rank generalized additive models text embedding

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Does installing photovoltaic panels affect daily electricity usage patterns? A generalized additive model approach

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ENERGY AND CLIMATE CHANGE 2021年 2卷

作者： Bhushan, Nitin Steg, Linda Jans, Lise Albers, Casper Univ Groningen Heymans Inst Psychol Res Fac Behav & Social Sci Grote Kruisstraat 2-1 NL-9712TS Groningen Netherlands

Installing photovoltaic panels (PV) on household rooftops can significantly contribute to mitigating anthropogenic climate change. The mitigation potential will be much higher when households would use PVs in a sustainable way, that is, if they match their electricity demand to their PVs electricity production, as to avoid using electricity from the grid. Whilst some have argued that owning PVs motivate households to use their PV in a sustainable way, others have argued that owning a PV does not result in load shifting, or that PV owners may even use more energy when their PV production is low. This paper addresses this critical issue, by examining to what extent PV owners are likely to shift their electricity demand to reduce the use of electricity from the grid. Extending previous studies, we analyse actual high frequency electricity use from the grid using smart meter data of households with and without PVs. Specifically, we employ generalized additive models to examine whether hourly net electricity use (i.e., the difference between electricity consumed from the grid and supplied back to the grid) of households with PVs is not only lower during times when PV production is high, but also when PV production low, compared to households without PVs. Results indicate that during times when PV production is high, net electricity use of households with PV is negative, suggesting they sent back excess electricity to the power grid. However, we found no difference in net electricity use during times when PV production is low. This suggests that installing PV does not promote sustainable PV use, and that the mitigation potential of PV installment can be enhanced by encouraging sustainable PV use.

关键词： Climate change Renewable energy Photovoltaic panels Sustainable PV use Smart meter data generalized additive models

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A hybrid CART-GAMs model to evaluate benthic macroinvertebrate habitat suitability in the Pearl River Estuary, China

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ECOLOGICAL INDICATORS 2022年第0期143卷

作者： Shen, Zhoubao Yang, Ying Ai, Lisha Yu, Chunxue Su, Meirong Dongguan Univ Technol Res Ctr Ecoenvironm Engn Dongguan 523808 Peoples R China

Benthic macminvertebrates are an important part of the aquatic food chain in estuaries. Therefore, understanding their associated habitat requirements is critical in maintaining estuarine ecosystem stability, which has until now been evaluated using habitat suitability evaluations. Although most habitat suitability index (HSI)-based methods can determine the target species preferences for a few specific habitat factors, benthic macroinvertebrates are influenced by multiple habitat factors in estuaries. However, applying too many habitat factors can result in data redundancy, thereby reducing model efficiency. Additionally, nonlinear relationships between species and habitat factors and interactions between different habitat factors are often difficult to evaluate. Previous studies have not focused on methods that can simultaneously address these two issues. Accordingly, this study introduced CART-GAMs, a classification and regression tree model (CART) and a generalized additive model (GAM) hybrid, which can evaluate the suitability of multiple habitat factors relevant to benthic macroinvertebrates in estuaries. First, to remove irrelevant variables (i.e., data redundancy), CART was used to identify critical habitat factors that have significant impacts on benthic macminvertebrates. GAMs were then used to quantify the nonlinear relationships between critical habitat factors and species. Finally, response curves fitted by GAMs were used to determine species habitat preferences (i.e., suitable critical habitat factor ranges). This study applied the CART-GAMs model to the Pearl River Estuary (PRE) to test its effectiveness. The results showed that CART identified four critical water quality factors, that is, salinity (SAL), total phosphorus (TP), pH, and ammonia nitrogen (NH3-N) from the 12 measured factors, subsequently reducing data redundancy by 66.7%. Using critical water quality factors, GAMs explained 66.2% of the variance in Margate s diversity index (dM) of bent

关键词： Benthic macroinvertebrates Habitat suitability evaluations Pearl River Estuary Classification and regression tree model generalized additive models

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Trends of lake temperature, mixing depth and ice cover thickness of European lakes during the last four decades

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SCIENCE OF THE TOTAL ENVIRONMENT 2022年 830卷 154709页

作者： Stefanidis, Konstantinos Varlas, George Papaioannou, George Papadopoulos, Anastasios Dimitriou, Elias Hellen Ctr Marine Res Inst Marine Biol Resources & Inland Waters 46-7 Km Athens Sounio Ave Anavyssos 19013 Attica Greece Univ Patras Dept Biol Univ Campus Rio GR-26500 Patras Greece Democritus Univ Thrace Dept Forestry & Management Environm & Nat Resourc Orestiada 68200 Greece

Lakes are particularly vulnerable ecosystems to global warming. Surface temperature of most lakes in the world has significantly increased. Here, we analysed time-series of water temperature, mixing-depth, and ice depth of 51 European lakes over the last four decades. We used data of surface temperature, total layer water temperature, mix-layer temperature, mix-layer depth, and ice cover depth obtained from the ERA5-land reanalysis dataset. Our main objectives were a) to identify significant changes of the examined variables that have occurred from 1981 to 2019 and h) to assess the variability of changes in relation with geographical and lake morphological gradients. To this end, time series analysis was conducted using generalized additive models (GAMs). In addition, we quantified the magnitude of change by estimating the Sen's slopes for each variable and then we examined the variability of these slopes to geographical and lake morphological parameters using GAMs. Our results confirmed that water temperature parameters (surface, total-layer and mix-layer temperature) have significantly increased for all lakes during the last four decades. We also found significant changes of the mixing depth for 14 lakes. In addition, the lake ice depth has significantly decreased in all fifteen lakes of the subarctic climate region. Finally, we showed that the Seds slopes depend on the geographic coordinates and the elevation of the lakes, whereas lake morphometry (e.g. depth has a smaller effect on the magnitude of changes. These findings hint that lake ecosystems of Europe have substantially changed over the last forty years and urge the need to take precautionary measures to prevent future implications for the freshwater biota.

关键词： Lakes Global warming Water temperature generalized additive models Climate reanalysis

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Spatial-temporal trends in the risk of illicit drug toxicity death in British Columbia

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BMC PUBLIC HEALTH 2022年第1期22卷 2121-2121页

作者： Hu, Kevin Klinkenberg, Brian Gan, Wen Qi Slaunwhite, Amanda K. British Columbia Ctr Dis Control 655 West 12th Ave Vancouver BC V5Z 4R4 Canada Univ British Columbia Dept Geog Vancouver BC Canada Univ British Columbia Sch Populat & Publ Hlth Vancouver BC Canada

Background Illicit drug poisoning (overdose) continues to be an important public health problem with overdose-related deaths currently recorded at an unprecedented level. Understanding the geographic variations in fatal overdose mortality is necessary to avoid disproportionate risk resulting from service access inequity. Methods We estimated the odds of fatal overdose per event from all cases captured by the overdose surveillance system in British Columbia (2015 - 2018), using both conventional logistic regression and generalized additive models (GAM). The results of GAM were mapped to identify spatial-temporal trends in the risk of fatal overdose. Results We found that the odds of fatal overdose were about 30% higher in rural areas than in large urban centers, with some regions reporting odds 50% higher than others. Temporal variations in fatal overdose revealed an increasing trend over the entire province. However, the increase occurred earlier and faster in the Interior and Northern regions. Conclusion Rural areas were disproportionately affected by fatal overdose;lack of access to harm reduction services may partly explain the elevated risk in these areas.

关键词： Overdose Harm reduction Healthcare access generalized additive models GIS

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Distribution of acoustic fish backscatter associated with natural and artificial reefs in the Northeastern Gulf of Mexico

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FISHERIES RESEARCH 2022年 248卷 106199-106199页

作者： White, Allison L. Patterson, William F. Boswell, Kevin M. Florida Int Univ Inst Environm Dept Biol Biscayne Bay Campus3000 NE 151st St North Miami Beach FL 33181 USA Univ Florida Fisheries & Aquat Sci 7922 NW 71St St Gainesville FL 32653 USA

Artificial reefs have been deployed throughout the northern Gulf of Mexico in an effort to enhance fish production and mitigate losses from the depletion of natural habitats. Measuring the efficacy of artificial reefs in these capacities requires both fine- and large-scale direct comparisons between natural and artificial reef structures. We conducted mobile active acoustic surveys to examine intra-reef and regional spatial patterns of acoustic fish backscatter in similar to 2 km(2) survey areas over 14 natural and 17 artificial reefs along the northwestern Florida continental shelf. Nested generalized additive models (GAMs) showed that intra-reef backscatter from fish at natural reefs was diffused throughout the survey area forming low density patches, whereas backscatter at artificial reefs was concentrated in high density hot-spots that were constricted horizontally within a mean of 116 m away from the structure. The exact distance from artificial structures at which backscatter was decreased to background levels, termed the area of influence, was found to be mediated by reef longitude, relief, area, and depth. On a regional scale, hierarchical GAMs (HGAMs) which incorporated altitude from the seafloor explained a larger proportion of deviance in backscatter than either latitude or longitude at both habitat types, indicating that the horizontal distribution of backscatter at these habitats varied throughout the water column. Trends in the horizontal distribution of backscatter were primarily driven by scatterers within 20 m of the seafloor at natural reefs and within 10 m of the surface at both natural and artificial reefs. HGAMs which examined only the horizontal distribution of backscatter showed a negative gradient of fish backscatter at natural reefs from west to east along the northwestern Florida continental shelf which was significantly influenced by reef depth. At both reef types, backscatter from fish was highest in the bottom 10 m of the water column an

关键词： Fishery acoustics Artificial and natural reefs Spatial distribution Area of influence generalized additive models Gulf of Mexico

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Historical population dynamics of the Adelie penguin in response to atmospheric-ocean circulation patterns at Beaufort Island, Ross Sea, Antarctica

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GLOBAL AND PLANETARY CHANGE 2022年 216卷

作者： Zheng, Zhangqin Nie, Yaguang Chen, Xin Jin, Jing Chen, Qianqian Liu, Xiaodong Univ Sci & Technol China Sch Earth & Space Sci Anhui Prov Key Lab Polar Environm & Global Change Hefei 230026 Anhui Peoples R China Anhui Univ Inst Phys Sci & Informat Technol Informat Mat & Intelligent Sensing Lab Anhui Prov Hefei 230601 Peoples R China Shanghai Jiao Tong Univ Sch Oceanog Shanghai 200240 Peoples R China USTC City U Joint Adv Res Ctr Suzhou 215123 Jiangsu Peoples R China Anhui Prov Comm CPC Party Sch Hefei 230022 Peoples R China Univ Sci & Technol China Sch Earth & Space Sci CAS Key Lab Crust Mantle Mat & Environm Hefei 230026 Peoples R China

Changes in sea ice extent and polynya size and productivity associated with climate conditions in the Ross Sea region have an important role on the ecological responses of Adelie penguins (Pygoscelis adeliae). Nevertheless, there have been few studies that elaborate on the effects of atmospheric and oceanic circulation on their populations. Here, we reconstructed the population dynamics of Adelie penguins on Beaufort Island during the past 350 years using various alternative geochemical indices and generalized additive models (GAMs). We explored the effects of atmospheric-ocean circulation patterns, including the El Nino-Southern Oscillation (ENSO), the Southern Annular Mode (SAM), and the Amundsen Sea Low (ASL), on the population ecology of penguins. The results indicated that their population on the island has been growing with fluctuations since similar to 1650 AD, and there were three significant increases, corresponding to 1650-1750, 1825-1900 and after 1950 AD. It was revealed that climate warming in this region was not a necessary factor for penguin population growth, since their populations maintained an increasing trend during the Little Ice Age (LIA) when relatively colder climate conditions prevailed. The present results indicated that atmospheric-ocean circulation patterns likely impose prominent influences on the historical change of penguin populations on Beaufort Island.

关键词： Climate change Adelie penguin population generalized additive models Ornithogenic sediments

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