Geology topics

Roger Sayre

Publications and source records attributed to Roger Sayre.

At least 19 recordsLinked to original sources

USGS2026

Ecological Benthic Units (EBUs): A new characterization of the global seafloor for ocean spatial planning and management

Effective management of deep-sea ecosystems and the high seas is hindered by the absence of a globally consistent framework for characterizing benthic habitats. Here we present the first global ecological classification of the seafloor, comprising 250 unique ecological benthic units (EBUs), distributed on the seafloor as nearly 700,000 EBU polygon occurrences, generated by intersecting a high-resolution geomorphic map with multivariate environmental seascapes. Using 17 million seafloor data points and 0.05° resolution biophysical datasets—including bottom temperature, dissolved oxygen, pH, carbon flux, sediment thickness, crustal age, and bottom currents—we identified 57 benthic regions across six major geomorphic groups (shelves, slopes, seamounts/guyots, spreading ridges, abyssal/hadal areas, plateaus). The resulting EBUs reveal previously unrecognized ecological gradients, quantify global patterns of benthic heterogeneity, and expose large-scale environmental vulnerabilities. Notably, we find that 95.6 million km 2 (26% of the ocean area) of abyssal seafloor lies below the carbonate compensation depth, that 4.16 million km 2 (1% of the ocean) of continental slopes intersect severe oxygen minima, and <1% of seamounts occur in seascapes most environmentally favorable to life. These insights provide a powerful basis for identifying rare habitat configurations, assessing exposure to climate-driven stressors, and prioritizing areas for high seas marine protected area planning, as well as a policy-relevant foundation for environmental impact assessment and biodiversity baseline proxies under the new United Nations High Seas Treaty.

Oceanography↗

USGS2026

A new inventory and conservation assessment of United States islands

To support conservation-focused research and management we developed a new 30-m resolution polygon data layer of the nonlacustrine and nonriverine islands of the United States, with associated attributes describing key physical and conservation geography characteristics. Islands were grouped into a three-tiered hierarchy of island regions (twelve), island provinces (twenty-eight), and individual islands (19,023). Islands were classified as either continental or oceanic based on their physiographic position relative to the North America continental shelf, and estuarine versus nonestuarine depending on their location within or external to estuaries. For each island we assessed the diversity of terrestrial and coastal ecosystems, the number of threatened and endangered (T&E) species listed under the Endangered Species Act, the number of T&E species critical habitats, the number of migratory bird species listed under the Migratory Bird Treaty Act, the number of Key Biodiversity Areas, and the number of and management responsibility for protected areas. We conclude that the conservation importance of islands is disproportionate to their total area as, for example, islands contain 52 percent of the T&E species yet their total area is only 2 percent of the area of the continental mainland. Similarly, of the global total of 431 World Terrestrial Ecosystems, 201 (47 percent) occur on U.S. islands compared with 286 (66 percent) that occur on the U.S. continental mainland.

Annals of the American Association of Geographers↗

USGS2025

A crosswalk of the 2015 World Terrestrial Ecosystems to the International Union for the Conservation of Nature Global Ecosystem Typology Framework

To support ecosystem mapping and accounting applications, we aligned the 2015 U.S. Geological Survey/Esri/The Nature Conservancy-World Terrestrial Ecosystems (WTEs) with the International Union for Conservation of Nature Global Ecosystem Typology (GET) framework. This process, known as “crosswalking,” enabled the development of a global map of GET level 3 Ecosystem Functional Groups (EFGs) at a 250-meter spatial resolution. Crosswalking involved manually assigning 1,781 biogeographically stratified WTEs to their most probable EFG based on similarities in climate, terrain, vegetation, and geographic distribution. We compared attributes of the WTE dataset with summary characteristics of the EFGs. The resulting crosswalked global map of International Union for Conservation of Nature GET ecosystems is intended to be useful for standardizing ecosystem classification and reporting under frameworks such as the Kunming-Montreal Global Biodiversity Framework and the United Nations System of Environmental-Economic Accounting. We discuss key challenges in reconciling non-identical classifications, such as many-to-one relationships and variation in data quality.

Open-File Report↗

USGS2024

Potential 2050 distributions of World Terrestrial Ecosystems from projections of changes in World Climate Regions and Global Land Cover

The urgency to address ecosystem loss is paramount, as both land use change and climate change will continue to rapidly alter and degrade natural ecosystems and reduce the many services they provide. To support conservation actions that mitigate impacts from these dual threats, we have developed potential World Terrestrial Ecosystem (WTE) distributions for 2050 following IPCC best practice guidelines. This projection of ecosystem distributions builds on the previously released 2015 WTEs, a snapshot of the distribution and conservation status of 431 terrestrial ecosystem types defined as distinct combinations of 18 global climate regions, 4 global landform classes, and 8 global vegetation/land cover classes. Extending that work herein, we modeled the potential 2050 WTE distributions based on projections of five CMIP6 general circulation models (GCMs) and one global land cover change model, determined for three shared socioeconomic pathway (SSP) scenarios. The climate region modeling included projections for 2050 for both mean annual temperature and mean annual aridity. Model agreement for changes to WTEs was generally high, particularly for temperature projections. Widespread changes in ecosystem classes due to shifts in climate settings and/or land cover between 2015 and 2050 were projected, with both the magnitude and specific geography of projected change largely governed by the SSP scenario. For the three SSP scenarios (sustainable development, regional rivalry, and fossil-fueled development), geographic changes in climate setting (temperature, aridity, or both) and/or changes in vegetation/land cover are projected for 29 %, 36 %, and 39 % of Earth’s terrestrial surface, respectively. These changes occur in areas where 31 %, 36 %, and 41 % of the global population lives. Projected changes in ecosystem distributions related to temperature change are approximately an order of magnitude greater than for aridity change. By offering insight into potential ecosystem changes, this new resource is intended to facilitate conservation planning and priority setting aimed at improved conservation of biodiversity and ecosystem services.

Global Ecology and Conservation↗

USGS2024

Toward a set of essential biodiversity variables for assessing change in mountains globally

Mountain regions harbor unique and rich biodiversity, forming an important part of our global life support system. This rich biodiversity underpins the ecological intactness and functioning of mountain ecosystems, which are imperative for the provision of key ecosystem services. A considerable amount of data are required to assess ecological intactness and ecosystem functioning and, given the profound anthropogenic pressures many mountain regions are being subjected to, are urgently needed. However, data on mountain biodiversity remain lacking. The essential biodiversity variables (EBVs) framework can help focus efforts related to detecting, investigating, predicting, and managing global biodiversity change, but has not yet been considered in the context of mountains. Here, we review key biological processes and physical phenomena that strongly influence mountain biodiversity and ecosystems and elucidate their associations with potential mountain EBVs. We identify seven EBVs of highest relevance for tracking and understanding the most critical drivers and responses of mountain biodiversity change. If they are implemented, the selected EBVs will contribute useful information to inform management and policy interventions seeking to halt mountain biodiversity loss and maintain functional mountain ecosystems.

BioScience↗

USGS2024

Increasing seasonal variation in the extent of rivers and lakes from 1984 to 2022

Knowledge of the spatial and temporal distribution of surface water is important for water resource management, flood risk assessment, monitoring ecosystem health, constraining estimates of biogeochemical cycles and understanding our climate. While global-scale spatiotemporal change detection of surface water has significantly improved in recent years due to planetary-scale remote sensing and computing, it has remained challenging to distinguish the changing characteristics of rivers and lakes. Here we analyze the spatial extent of permanent and seasonal rivers and lakes globally over the past 38 years based on new data of river system extents and surface water trends. Results show that while the total permanent surface area of both rivers and lakes has remained relatively constant, the areas with intermittent seasonal coverage have increased by 12 % and 27 % for rivers and lakes, respectively. The increase is statistically significant in over 84 % of global water catchments based on Spearman's rank correlations (rho) above 0.05 and p values less than 0.05. The seasonal river extent is nearly 32 % larger than the previously observed annual mean river extent, suggesting large seasonal variations that impact not only ecosystem health but also estimations of terrestrial biogeochemical cycles of carbon. The outcomes of our analysis are shared as the Surface Area of Rivers and Lakes (SARL) database, serving as a valuable resource for monitoring and research of hydrological cycles, ecosystem accounting, and water management.

Hydrology and Earth System Sciences↗

USGS2023

Named landforms of the World: A geomorphological and physiographic compilation

Prior to the current era of digital geomorphological mapping, global and regional-scale land surface characterization was advanced by qualitative interpretations that relied on human visualization aided by disciplinary knowledge of geophysical processes combined with extensive field study. In the early twentieth century, Fenneman proposed to devise systematic physiographic divisions of the United States and in 1916 produced what is still regarded as an authoritative map of these divisions. His physiographic regions were developed to provide context when describing land surface characteristics of smaller areas using well-known regional characteristics and descriptors. In 1968, geographer Richard E. Murphy published a large-format map of the “Landforms of the World” to fill a gap in the suite of standard classroom maps. In 1990, the British geomorphologist E. M. Bridges published World Geomorphology , providing the first global treatment and description of divisions, provinces, and sections—the same hierarchical land partitioning concepts that Fenneman used decades earlier. In the twenty-first century, geographic information systems (GIS) technologies are nearly ubiquitous, yet neither Murphy’s nor Bridges’s work existed as GIS data. To further illuminate their pioneering work, we (1) recompiled Murphy’s landforms as a spatial combination of modern existing data layers, and (2) used the recompiled Murphy’s landforms as a basis for the boundaries of the divisions, provinces, and sections described by Bridges. Our aggregation yields a new resource, Named Landforms of the World, version 2.0, which provides a reference-level, basemap-quality data layer that can significantly facilitate mapping, assessing, and understanding Earth surface features.

Annals of the AAG↗

USGS2023

Space-based Earth observation and ecosystem extent: Exploring opportunities

The purpose of this white paper is to explore and communicate potential new opportunities for using space-based Earth observation (EO) for monitoring biodiversity with a focus on ecosystem extent (the distribution of ecosystems on the Earth). It is part of a new activity of the Committee on Earth Observation Satellites (CEOS), a collaboration of the world’s space agencies that facilitates cross-agency coordination of EO. This activity, now manifested as the CEOS Ecosystem Extent Task Team, is focused on increasing the CEOS role in biodiversity applications, initially using ecosystem extent as a vehicle for discussion and exploration of ideas. The audience is two-fold: CEOS Principals that represent their agency, and the biodiversity community with a particular focus on the Convention on Biological Diversity (CBD) and their Parties as well as the UN System of Environmental-Economic Accounting (UN SEEA).

Report↗

USGS2022

Human populations in the world’s mountains: Spatio-temporal patterns and potential controls

Changing climate and human demographics in the world's mountains will have increasingly profound environmental and societal consequences across all elevations. Quantifying current human populations in and near mountains is crucial to ensure that any interventions in these complex social-ecological systems are appropriately resourced, and that valuable ecosystems are effectively protected. However, comprehensive and reproducible analyses on this subject are lacking. Here, we develop and implement an open workflow to quantify the sensitivity of mountain population estimates over recent decades, both globally and for several sets of relevant reporting regions, to alternative input dataset combinations. Relationships between mean population density and several potential environmental covariates are also explored across elevational bands within individual mountain regions (i.e. sub-mountain range scale). Globally, mountain population estimates vary greatly from 0.344 billion (<5% of the corresponding global total) to 2.289 billion (>31%) in 2015. A more detailed analysis using one of the population datasets (GHS-POP) revealed that in 35% of mountain sub-regions, population increased at least twofold over the 40-year period 19752015. The urban proportion of the total mountain population in 2015 ranged from 6% to 39%, depending on the combination of population and urban extent datasets used. At sub-mountain range scale, population density was found to be more strongly associated with climatic than with topographic and protected-area variables, and these relationships appear to have strengthened slightly over time. Such insights may contribute to improved predictions of future mountain population distributions under scenarios of future climatic and demographic change. Overall, our work emphasizes that irrespective of data choices, substantial human populations are likely to be directly affected by and themselves affect mountainous environmental and ecological change. It thereby further underlines the urgency with which the multitudinous challenges concerning the interactions between mountain climate and human societies under change must be tackled.

PLoS ONE↗

USGS2022

Ecological Coastal Units – Standardized global shoreline characteristics

A new set of resources is now available that describe global shoreline characteristics. High resolution (30 m), globally comprehensive Coastal Segment Units (CSUs) and Ecological Coastal Units (ECUs) were developed in a collaboration between the U.S. Geological Survey (USGS), Esri, and the Marine Biodiversity Observation Network (MBON). The data were produced from a segmentation and characterization of a global shoreline vector extracted from year 2014 Landsat imagery. A total of 4 million 1 km shoreline segments were attributed with values from ten variables which describe the ecological settings in which the coastline occurs, including water-side properties, landside properties, and properties of the coastline itself. These data were developed as part of a Group on Earth Observations (GEO) global ecosystem mapping initiative called GEO Ecosystems (GEO ECO). The development of the resource and its intended utility are reviewed herein.

Conference Paper↗

USGS2021

A global ecological classification of coastal segment units to complement marine biodiversity observation network assessments

A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels for global coastal segments at 1 km or shorter resolution. These characteristics are summarized for six US Marine Biodiversity Observation Network (MBON) sites and one MBON Pole to Pole of the Americas site in Argentina. The global coastlines CMECS classifications were produced from a partitioning of a 30 m Landsat-derived shoreline vector that was segmented into 4 million 1 km or shorter segments. Each segment was attributed with values from 10 variables that represent the ecological settings in which the coastline occurs, including properties of the adjacent water, adjacent land, and coastline itself. The 4 million segments were classified into 81,000 coastal segment units (CSUs) as unique combinations of variable classes. We summarize the process to develop the CSUs and derive summary descriptions for the seven MBON case study sites. We discuss the intended application of the new CSU data for research and management in coastal areas.

Oceanography↗

USGS2021

Identification of Global Priorities for New Mountain Protected and Conserved Areas

Mountain ecosystems are extremely diverse and fragile. They include astonishing biodiversity in terms of number of taxa and endemicity, and globally provide the most diverse range of ecosystem services. The world’s system of protected and conserved areas includes many outstanding areas within the earth’s mountainous landscape: about 19% of mountain areas are protected or conserved, globally. Furthermore, approximately 90% of the most-strongly-protected conservation estate occurs in mountains. Nevertheless, significant mountain areas are not adequately protected, and many mountain ranges are completely unprotected. Of over 6000 Key Biodiversity Areas (KBAs) in mountains worldwide, 40.4% are entirely unprotected. As the world conservation movement advocates to expand the global coverage of terrestrial protected areas over the next decade toward 30%, identifying priorities for new mountain protected and conserved areas will be most efficacious if it takes a strategic approach to ensure areas of highest value and most in need of protection are identified. This paper introduces an iterative six-step decision support tool for identifying and prioritizing candidate areas for conserving inadequately protected mountain ecosystems, species, and habitats. The tool begins with quantitative analyses of the adequacy of protection of mountain KBAs, world terrestrial ecosystems, biodiversity hotspots, and red-listed species. It then guides regional teams through qualitative assessments of other values to develop lists of priority areas to give heightened consideration for protection or conservation. The tool is framed on the notion that any of the more than 6000 mountain KBAs can be allocated into one of nine categories: four that identify inadequately protected areas prioritised for heightened consideration, two for which no further action is required unless circumstances change, and three not requiring further action due to being deemed adequately protected.

Final Report↗

USGS2021

Earth's coastlines

With approximately half the world’s population living less than 65 miles from the ocean, coastal ecosystems are arguably Earth’s most critical real estate. Yet coastlines are among the more difficult features to accurately map; until now, no comprehensive high-resolution geospatial dataset existed. This chapter presents a new map and ecological inventory of global coastlines developed by Esri, the U.S. Geological Survey, and other partners.

Book chapter↗

USGS2020

Global islands

A new map of global islands at a high spatial resolution (30 m) has been produced from a semi-automated interpretation of 2014 satellite imagery. The data are available in the public domain. The islands were classified by size into continental mainlands (5), big islands > 1 km 2 (21,818), and small islands ≤ 1 km 2 (318,868). The new high-resolution islands data are intended to support coastal ecosystem mapping efforts and assessments of threatened island biodiversity, among other applications. This chapter summarizes the global island mapping approach and results.

Book chapter↗

USGS2020

An assessment of the representation of ecosystems in global protected areas using new maps of World Climate Regions and World Ecosystems

Representation of ecosystems in protected area networks and conservation strategies is a core principle of global conservation priority setting approaches and a commitment in Aichi Target 11 of the Convention on Biological Diversity. The 2030 Sustainable Development Goals (SDGs) explicitly call for the conservation of terrestrial, freshwater, and marine ecosystems. Accurate ecosystem distribution maps are required to assess representation of ecosystems in protected areas, but standardized, high spatial resolution, and globally comprehensive ecosystem maps have heretofore been lacking. While macroscale global ecoregions maps have been used in global conservation priority setting exercises, they do not identify distinct localized ecosystems at the occurrence (patch) level, and instead describe large ecologically meaningful areas within which additional conservation planning and management are necessary. We describe a new set of maps of globally consistent climate regions and ecosystems at a much finer spatial resolution (250 m) than existing ecological regionalizations. We then describe a global gap analysis of the representation of these ecosystems in protected areas. The new map of terrestrial World Ecosystems was derived from the objective development and integration of 1) global temperature domains, 2) global moisture domains, 3) global landforms, and 4) 2015 global vegetation and land use. These new terrestrial World Ecosystems do not include either freshwater or marine ecosystems, but analog products for the freshwater and marine domains are in development. A total of 431 World Ecosystems were identified, and of these a total of 278 units were natural or semi-natural vegetation/environment combinations, including different kinds of forestlands, shrublands, grasslands, bare areas, and ice/snow regions. The remaining classes were different kinds of croplands and settlements. Of the 278 natural and semi-natural classes, 9 were not represented in global protected areas with a strict biodiversity conservation management objective (IUCN management categories I-IV), and an additional 206 were less than 8.5% protected (half way to the 17% Aichi Target 11 goal). Forty four classes were between 8.5% and 17% protected (more than half way towards the Aichi 17% target), and only 19 classes exceeded the 17% Aichi target. However, when all protected areas (IUCN management categories I-VI plus protected areas with no IUCN designation) were included in a separate global gap analysis, representation of ecosystems increases substantially, with a third of the ecosystems exceeding the 17% Aichi target, and another third between 8.5% and 17%. The overall protection (representation) of global ecosystems in protected areas is considerably less when assessed using only strictly conserved protected areas, and more if all protected areas are included in the analysis. Protected area effectiveness should be included in further evaluations of global ecosystem protection. The ecosystems with the highest representation in protected areas were often bare or sparsely vegetated and found in inhospitable environments (e.g. cold mountains, deserts), and the eight most protected ecosystems were all snow and ice ecosystems. In addition to the global gap analysis of World Ecosystems in protected areas, we report on the representation results for the ecosystems in each biogeographic realm (Neotropical, Nearctic, Afrotropical, Palearctic, Indomalayan, Australasian, and Oceania).

Global Ecology and Conservation↗

USGS2020

The geography of islands

Islands come in all shapes, sizes and types, from tiny rocky outcrops, to enormous continental landmasses. The true number of islands distributed in the planet’s seas and oceans is still elusive. Recent efforts bolstered by an abundance of detailed satellite imagery and the sophistication of geographic information systems (GIS) are bringing real answers to those questions closer than ever.

Book chapter↗

USGS2019

A multidisciplinary framework to derive global river reach classifications at high spatial resolution

Projected climate and environmental change are expected to increase the pressure on global freshwater resources. To prepare for and cope with the related risks, stakeholders need to devise plans for sustainable management of river systems, which in turn requires the identification of management-appropriate operational units, such as groups of rivers that share similar environmental and biological characteristics. Ideally, these units are of a manageable size, and are biotically or abiotically distinguishable across a variety of river types. Here, we aim to address this need by presenting a new global river classification framework (GloRiC) to establish a common vocabulary and standardized approach to the development of globally comprehensive and integrated river classifications that can be tailored to different goals and requirements. We define the GloRiC conceptual framework based on five categories of variables: (1) hydrology; (2) physiography and climate; (3) fluvial geomorphology; (4) water chemistry; and (5) aquatic biology. We then apply the framework using hydro-environmental attributes provided by a seamless high-resolution river reach database to create initial instances of three sub-classifications (hydrologic, physio-climatic, and geomorphic) which we ultimately combine into 127 river reach types at the global scale. These supervised classifications utilize a mix of statistical analyses and expert interpretation to identify the classifier variables, the number of classes, and their thresholds. In addition, we also present an unsupervised, multivariable k-means statistical clustering of all river reaches into 30 groups. These first-of-their-kind global river reach classifications at high spatial resolution provide baseline information for a total of 35.9 million kilometers of rivers that have been assessed in this study, and are expected to be particularly useful in remote or data-poor river basins. The GloRiC framework and associated data are primarily designed for broad and rapid applicability in assessments that require stratified analyses of river ecosystem conditions at global and regional scales; smaller-scale applications could follow the same conceptual framework yet use more detailed data sources.

Environmental Research Letters↗

USGS2019

The Islands of Oceania – Political geography, biogeography, and terrestrial ecosystems

Humans are dependent upon ecosystems for the production of goods and services necessary for their well-being (Daily, 1997). As the service provider units (SPUs) for these benefits of nature (Anderson et al., 2015), ecosystems need to be managed in a way that maximizes their persistence on the planet. Part of that management effort includes knowing a) what the ecosystem types are, b) where they are located on the landscape and in the seascape, and c) what condition they are in. Mapping of ecosystem occurrences as the SPUs for ecosystems goods and services is therefore an important element of ecosystem accounting, an inherently spatial activity. Maps are also needed of the ecosystem accounting areas within which the accounting is conducted. Standardized maps of ecosystem accounting areas and terrestrial ecosystem SPUs have not previously been available for many islands of the Oceania region. We describe the availability of new island shorelines and ecosystems data for Oceania herein, and encourage consideration and evaluation of the data for ecosystem accounting and other applications.

Ecosystem Services↗