Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

This paper describes the technical development and accuracy assessment of the most recent and improved version of the SoilGrids system at 250m resolution (June 2016 update). SoilGrids provides global predictions for standard numeric soil properties (organic carbon, bulk density, Cation Exchange Capacity (CEC), pH, soil texture fractions and coarse fragments) at seven standard depths (0, 5, 15, 30, 60, 100 and 200 cm), in addition to predictions of depth to bedrock and distribution of soil classes based on the World Reference Base (WRB) and USDA classification systems (ca. 280 raster layers in total). Predictions were based on ca. 150,000 soil profiles used for training and a stack of 158 remote sensing-based soil covariates (primarily derived from MODIS land products, SRTM DEM derivatives, climatic images and global landform and lithology maps), which were used to fit an ensemble of machine learning methods-random forest and gradient boosting and/or multinomial logistic regression-as implemented in the R packages ranger, xgboost, nnet and caret. The results of 10-fold cross-validation show that the ensemble models explain between 56% (coarse fragments) and 83% (pH) of variation with an overall average of 61%. Improvements in the relative accuracy considering the amount of variation explained, in comparison to the previous version of SoilGrids at 1 km spatial resolution, range from 60 to 230%. Improvements can be attributed to: (1) the use of machine learning instead of linear regression, (2) to considerable investments in preparing finer resolution covariate layers and (3) to insertion of additional soil profiles. Further development of SoilGrids could include refinement of methods to incorporate input uncertainties and derivation of posterior probability distributions (per pixel), and further automation of spatial modeling so that soil maps can be generated for potentially hundreds of soil variables. Another area of future research is the development of methods for multiscale merging of SoilGrids predictions with local and/or national gridded soil products (e.g. up to 50 m spatial resolution) so that increasingly more accurate, complete and consistent global soil information can be produced. SoilGrids are available under the Open Data Base License.

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SoilGrids250m: Global gridded soil information based on machine learning

▪ Abstract Estimates of global wetland area range from 5.3 to 12.8 million km2. About half the global wetland area has been lost, but an international treaty (the 1971 Ramsar Convention) has helped 144 nations protect the most significant remaining wetlands. Because most nations lack wetland inventories, changes in the quantity and quality of the world's wetlands cannot be tracked adequately. Despite the likelihood that remaining wetlands occupy less than 9% of the earth's land area, they contribute more to annually renewable ecosystem services than their small area implies. Biodiversity support, water quality improvement, flood abatement, and carbon sequestration are key functions that are impaired when wetlands are lost or degraded. Restoration techniques are improving, although the recovery of lost biodiversity is challenged by invasive species, which thrive under disturbance and displace natives. Not all damages to wetlands are reversible, but it is not always clear how much can be retained through re...

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Wetland resources : Status, trends, ecosystem services, and restorability

. The carbon burial in vegetated sediments, ignored in past assessments of carbon burial in the ocean, was evaluated using a bottom-up approach derived from upscaling a compilation of published individual estimates of carbon burial in vegetated habitats (seagrass meadows, salt marshes and mangrove forests) to the global level and a top-down approach derived from considerations of global sediment balance and a compilation of the organic carbon content of vegeatated sediments. Up-scaling of individual burial estimates values yielded a total carbon burial in vegetated habitats of 111 Tmol C y-1. The total burial in unvegetated sediments was estimated to be 126 Tg C y-1, resulting in a bottom-up estimate of total burial in the ocean of about 244 Tg C y-1, two-fold higher than estimates of oceanic carbon burial that presently enter global carbon budgets. The organic carbon concentrations in vegetated marine sediments exceeds by 2 to 10-fold those in shelf/deltaic sediments. Top-down recalculation of ocean sediment budgets to account for these, previously neglected, organic-rich sediments, yields a top-down carbon burial estimate of 216 Tg C y-1, with vegetated coastal habitats contributing about 50%. Even though vegetated carbon burial contributes about half of the total carbon burial in the ocean, burial represents a small fraction of the net production of these ecosystems, estimated at about 3388 Tg C y-1, suggesting that bulk of the benthic net ecosystem production must support excess respiration in other compartments, such as unvegetated sediments and the coastal pelagic compartment. The total excess organic carbon available to be exported to the ocean is estimated at between 1126 to 3534 Tg C y-1, the bulk of which must be respired in the open ocean. Widespread loss of vegetated coastal habitats must have reduced carbon burial in the ocean by about 30 Tg C y-1, identifying the destruction of these ecosystems as an important loss of CO2 sink capacity in the biosphere.

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Major role of marine vegetation on the oceanic carbon cycle

. In this forum paper we discuss how soil scientists can help to reach the recently adopted UN Sustainable Development Goals (SDGs) in the most effective manner. Soil science, as a land-related discipline, has important links to several of the SDGs, which are demonstrated through the functions of soils and the ecosystem services that are linked to those functions (see graphical abstract in the Supplement). We explore and discuss how soil scientists can rise to the challenge both internally, in terms of our procedures and practices, and externally, in terms of our relations with colleague scientists in other disciplines, diverse groups of stakeholders and the policy arena. To meet these goals we recommend the following steps to be taken by the soil science community as a whole: (i) embrace the UN SDGs, as they provide a platform that allows soil science to demonstrate its relevance for realizing a sustainable society by 2030; (ii) show the specific value of soil science: research should explicitly show how using modern soil information can improve the results of inter- and transdisciplinary studies on SDGs related to food security, water scarcity, climate change, biodiversity loss and health threats; (iii) take leadership in overarching system analysis of ecosystems, as soils and soil scientists have an integrated nature and this places soil scientists in a unique position; (iii) raise awareness of soil organic matter as a key attribute of soils to illustrate its importance for soil functions and ecosystem services; (iv) improve the transfer of knowledge through knowledge brokers with a soil background; (v) start at the basis: educational programmes are needed at all levels, starting in primary schools, and emphasizing practical, down-to-earth examples; (vi) facilitate communication with the policy arena by framing research in terms that resonate with politicians in terms of the policy cycle or by considering drivers, pressures and responses affecting impacts of land use change; and finally (vii) all this is only possible if researchers, with soil scientists in the front lines, look over the hedge towards other disciplines, to the world at large and to the policy arena, reaching over to listen first, as a basis for genuine collaboration.

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The significance of soils and soil science towards realization of the United Nations sustainable development goals

The International Society of Soil Science (ISSS) was founded in 1924 in Rome, Italy, by European agro-geologists who were interested in establishing standardized methods of soil analysis and soil classification. It was admitted as a Union member of the International Council for Science (ICSU) in 1993 and was restructured into the International Union of Soil Sciences (IUSS) in 1998. The objectives of the IUSS are to promote all branches of soil science, and to support all soil scientists across the world in the pursuit of their activities.

Some History and Accomplishments of the IUSS

The pollution of aquatic ecosystems is an issue facing many countries all over the world and may result in issues such as eutrophication in coastal zones. Managing this eutrophication is a real challenge. The current study focuses on the investigation and identification of aquatic environmental characteristics, including the sediments, waters, and seaweed, of seven eutrophicated locations along the Mediterranean coast of Alexandria (Egypt). Different ecological risk assessment and bioaccumulation factors were calculated in order to identify the probable pollution source and the degree of the problem, in addition to the accumulation of heavy metals in the seaweed. The characteristics of the seaweed, sediments, and waters were chemically analyzed and heavy metals were measured. The genetically and biochemically identified seaweed species were Ulva compressa, Ulva fasciata, Ulva lactuca and Ulva linzea. The sediments of the El-Tabia location contained the highest concentrations of Cd, Co, Ni, and Pb, because this location receives these elements from the El-Amia drain. The Abu Qir location was found to contain the highest concentrations of the same heavy metals in the studied water samples because it was located much closer to the Abu Qir harbor. Ecological risk assessment indices indicated moderate to high contamination for most of the studied elements and locations. The results of the bioaccumulation factor analysis indicated that the studied seaweed species are accumulators of trace elements. These seaweed species should be further investigated concerning ecotoxicology if they are to be used in the human diet and for other benefits. This study opens many windows of research to be investigated in the future regarding the sustainable management of polluted coastal zones.

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Assessment of Bioaccumulation of Heavy Metals and Their Ecological Risk in Sea Lettuce (Ulva spp.) along the Coast Alexandria, Egypt: Implications for Sustainable Management

Degrees Earned by Faculty Teaching in Soil Science Preparatory Programs at Universities in the USA.

Soil mapping and processes models to support climate change mitigation and adaptation strategies: a review

Soil is an important source of resources required for human health and well-being. Soil is also a major environmental reservoir of pathogenic organisms. This may include viruses like the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which through 2020 and 2021 created dramatic catastrophes worldwide as the causative agent of the coronavirus disease of 2019 (COVID-19). So, soil has both positive and negative impacts on human health. One of the major positive impacts is the transfer of nutrients from soil to plants, and from there to humans through their diet. Biofortification is able to enhance the levels of nutrients essential to human health in the crops we consume and represents a sustainable solution to address malnutrition, which in turn may strengthen the human immune system against COVID-19. This nutrient transfer works better when we have healthy soils. Therefore, soils and biofortification have important roles to play in combatting the COVID-19 pandemic. However, several questions still remain, such as what are the expected environmental impacts of COVID-19 on soil? Can SARS-CoV-2 be transmitted through soil, and under what conditions? Which soil processes and properties influence SARS-CoV-2 survival rates and times, as well as transmission? What are the specific links between soil health and COVID-19? What are the projected soil management scenarios in response to COVID-19? Questions such as these deserve more attention as the world seeks to recover from its most recent pandemic.

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Eric C. Brevik

Papers

Some History and Accomplishments of the IUSS

Assessment of Bioaccumulation of Heavy Metals and Their Ecological Risk in Sea Lettuce (Ulva spp.) along the Coast Alexandria, Egypt: Implications for Sustainable Management

Degrees Earned by Faculty Teaching in Soil Science Preparatory Programs at Universities in the USA.

Soil mapping and processes models to support climate change mitigation and adaptation strategies: a review

Soils, Biofortification, and Human Health Under COVID-19: Challenges and Opportunities