Introduction and Alignment with Sustainable Development Goals

A comprehensive understanding of global species distribution is fundamental for large-scale biodiversity conservation, directly supporting the United Nations Sustainable Development Goals (SDGs). This report details the development of the FreshVerts v1.0 database, a significant expansion and update of the 2008 Freshwater Ecoregions of the World (FEOW) framework. By cataloging all described freshwater-dependent vertebrates, this initiative provides a critical resource for monitoring and achieving key environmental targets.

The project directly addresses the following SDGs:

• SDG 15 (Life on Land): The database is a primary tool for implementing Target 15.1 (ensure the conservation and sustainable use of inland freshwater ecosystems), Target 15.5 (halt the loss of biodiversity and prevent the extinction of threatened species), and Target 15.9 (integrate ecosystem and biodiversity values into national and local planning).
• SDG 14 (Life Below Water): While focused on freshwater, the principles of conserving aquatic biodiversity and managing ecosystems sustainably are parallel to the aims of SDG 14, contributing to the overall health of global water systems.
• SDG 6 (Clean Water and Sanitation): The project supports Target 6.6, which calls for the protection and restoration of water-related ecosystems, by providing the baseline data necessary to identify and prioritize these areas.
• SDG 17 (Partnerships for the Goals): The creation of this database exemplifies a global partnership, integrating data from numerous scientific and conservation organizations to build a shared resource for sustainable development.

Freshwater ecosystems, including rivers, lakes, and wetlands, are disproportionately rich in biodiversity, hosting approximately 30% of all vertebrate species despite covering less than 1% of the Earth’s surface. However, these ecosystems are severely degraded and often underrepresented in conservation planning. The FreshVerts v1.0 database aims to rectify this by providing a robust, ecoregion-based framework for prioritizing conservation efforts, ensuring that actions to protect terrestrial biodiversity do not overlook the unique needs of freshwater life.

Methodological Framework for Global Biodiversity Assessment

The FreshVerts v1.0 database was assembled by systematically compiling and validating information on the geographical distribution of all freshwater vertebrate species and assigning them to the 426 established Freshwater Ecoregions of the World (FEOW). This process involved a multi-stage approach to ensure comprehensive taxonomic coverage and data accuracy, leveraging partnerships and public data repositories in line with SDG 17.

Data Compilation for Freshwater Tetrapods

The process for compiling data on freshwater-dependent mammals, birds, reptiles, and amphibians involved several key steps:

1. Initial Species List: A comprehensive list of tetrapod species was obtained from the IUCN Red List database (July 2022).
2. Defining “Freshwater-Dependent”: A critical step was to establish a strict definition. Species were included only if freshwater environments are essential for completing their life history (e.g., life cycle, habitat, or food). This excluded species with only occasional or facultative use of freshwater habitats.
3. Taxonomic Group Refinement:
   • Mammals: 127 freshwater-dependent species were identified.
   • Birds: A conservative approach was adopted, resulting in a list of 764 species that are obligate freshwater dwellers for breeding or feeding.
   • Reptiles: 639 species were included after expert review, using data primarily from the Global Assessment of Reptile Distributions (GARD) to supplement IUCN data.
   • Amphibians: Following established classifications, 5,089 species were identified as freshwater-dependent.
4. Ecoregional Assignment: Spatial data for each species was intersected with the 426 FEOW ecoregions. A validation process was implemented to remove potential false attributions at range boundaries.

Data Compilation for Freshwater Fishes

Updating the fish data was a major focus, given the rapid rate of new species discovery and the relative scarcity of consolidated data. This effort was crucial for addressing knowledge gaps that hinder the achievement of SDG 14 and 15.

1. Species List Expansion: The original FEOW list was compared against the 2022 FishBase database, identifying 4,027 additional freshwater fish species for inclusion.
2. Spatial Data Aggregation: Distribution information was systematically sourced from multiple databases in a hierarchical manner:
   • IUCN Red List
   • Global Biodiversity Information Facility (GBIF)
   • FishBase
3. Literature-Based Gap Filling: For 958 species lacking spatial information in standard repositories, an extensive bibliographic search was conducted to retrieve reliable distribution data from scientific literature. This labor-intensive process successfully assigned ranges to 848 additional species.
4. Taxonomic Harmonization: All fish names were updated to the 2024 nomenclature using the Eschmeyer Catalog of Fishes, ensuring consistency and removing redundancies. This resulted in a final, validated list of 16,512 freshwater fish species.

The final consolidated database, FreshVerts v1.0, contains 96,129 ecoregional population records for 23,130 freshwater vertebrate species, providing an unprecedented resource for global conservation planning.

Database Composition and Data Records

The FreshVerts v1.0 dataset is publicly available via the figshare data repository, promoting open access to scientific data in support of the SDGs. The database is structured to facilitate analysis and integration into conservation and policy frameworks.

• FEOW Shapefile: A map file containing the 426 freshwater ecoregions, providing the core spatial units for analysis.
• Freshwater Vertebrates by Ecoregion Table: The central component of the database, containing 96,129 records linking 23,130 species to their respective ecoregions. Each record includes detailed taxonomic information and the original data source.
• Discarded Tetrapod Records Table: This table provides transparency by listing records excluded during the validation process, detailing the reasoning for their exclusion.
• Ecoregional Biodiversity Indices Table: To support conservation prioritization aligned with SDG 15, this table provides key metrics for each ecoregion, including:
  • Species Richness
  • Endemicity (number of species found only in that ecoregion)
  • Rarity-Weighted Richness (RWR)
• Literature Search Data Table: This supplementary file documents the spatial information manually retrieved from scientific literature for 848 fish species, ensuring the reproducibility of the research.

Technical Validation and Future Directions

Rigorous validation was performed to ensure the integrity and reliability of the database, a prerequisite for its use in evidence-based decision-making for sustainable development.

Validation Procedures

• Taxonomic Consistency: All species names were standardized against authoritative taxonomic databases (IUCN Red List for tetrapods, Eschmeyer’s Catalog of Fishes for fish) to resolve synonyms and ensure accuracy.
• Spatial Attribution Validation: To address potential misattributions of tetrapod species at the edges of their ranges, a dual-threshold filter was applied. Ecoregional records were retained only if they represented more than 10% of the ecoregion’s area or more than 10% of the species’ global range. This conservative approach removed marginal records while retaining all species in the database.

Limitations and Future Updates

The FreshVerts v1.0 database is a dynamic resource intended for regular updates. The primary limitation is the coarse spatial resolution of ecoregions, though they remain highly relevant for global-scale analysis and prioritization. Future work, supported by ongoing partnerships (SDG 17), will focus on:

1. Incorporating newly described species, particularly fishes.
2. Updating species distributions and taxonomy as new information becomes available.
3. Refining the classification of freshwater-dependent species based on emerging research.

This database represents a foundational tool for the global community to analyze biodiversity patterns, prioritize conservation actions, and track progress towards the Sustainable Development Goals for protecting life in freshwater ecosystems.

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The article’s focus on cataloging freshwater vertebrate biodiversity, defining ecoregions for conservation, and creating an open-access database directly connects to several Sustainable Development Goals. The primary goals addressed are those concerning the protection of ecosystems and biodiversity, the management of water resources, and the collaborative efforts required to achieve these aims.

• SDG 15: Life on Land

  This is the most central SDG to the article. SDG 15 aims to “protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss.” The article’s entire purpose is to support the conservation of freshwater biodiversity, which falls under the umbrella of “inland freshwater ecosystems” mentioned in this goal. The creation of the FreshVerts v1.0 database is a direct contribution to understanding and protecting this biodiversity. The article states its goal is to provide a resource for “prioritizing efforts to conserve aquatic species.”

• SDG 6: Clean Water and Sanitation

  While the article does not discuss water quality or sanitation directly, it strongly connects to the ecosystem-focused aspects of SDG 6. Specifically, it addresses the need to protect the biological integrity of freshwater ecosystems. The article notes that “Rivers, lakes, and wetlands are exceptionally rich in biodiversity” but are also “more degraded by human activities than their terrestrial and marine counterparts,” highlighting the urgency of protecting these water-related ecosystems.

• SDG 17: Partnerships for the Goals

  The project described in the article is a clear example of SDG 17 in action. It involves a collaboration between multiple institutions, including “Cornell University, The Nature Conservancy, [and] WWF,” to “mobilize and share knowledge.” The creation and public dissemination of the FreshVerts v1.0 database on the Figshare repository exemplifies the goal of enhancing data sharing and multi-stakeholder partnerships to address global challenges like biodiversity loss.

2. What specific targets under those SDGs can be identified based on the article’s content?

The article’s content aligns with several specific targets within the identified SDGs, providing foundational data and tools necessary for their implementation and monitoring.

1. Targets under SDG 15 (Life on Land)

   • Target 15.1: “By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services…” The article directly supports this by delineating 426 freshwater ecoregions and providing a comprehensive species database, which it says “provides a resource for analyzing global biodiversity… and prioritizing efforts to conserve aquatic species.”
   • Target 15.5: “Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity and, by 2020, protect and prevent the extinction of threatened species.” The project’s use of the “IUCN Red List database” and its aim to create a comprehensive inventory of 23,130 species are fundamental actions required to identify threatened species and halt biodiversity loss.
   • Target 15.9: “By 2020, integrate ecosystem and biodiversity values into national and local planning…” The delineation of ecoregions and the associated biodiversity data are designed to “help to guide global prioritization of conservation efforts” and can be integrated into environmental management plans, as mentioned in the article.

2. Target under SDG 6 (Clean Water and Sanitation)

   • Target 6.6: “By 2020, protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, aquifers and lakes.” The article’s focus on “Rivers, lakes, and wetlands” and its effort to map the distribution of vertebrate species within these ecosystems provide a critical baseline for monitoring their health and guiding protection and restoration efforts.

3. Targets under SDG 17 (Partnerships for the Goals)

   • Target 17.16: “Enhance the global partnership for sustainable development, complemented by multi-stakeholder partnerships that mobilize and share knowledge, expertise, technology and financial resources…” The project itself, a collaboration between academic and conservation organizations (Cornell, The Nature Conservancy, WWF), is a direct manifestation of this target.
   • Target 17.18: “By 2020, enhance capacity-building support… to increase significantly the availability of high-quality, timely and reliable data disaggregated by… geographic location…” The article’s primary output, the “comprehensive and updated database of freshwater species by FEOW ecoregion” (FreshVerts v1.0), which is made publicly available, directly contributes to this target by providing globally accessible, geographically specific data.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

The article mentions or provides data for several official SDG indicators, which can be used to measure progress.

• Indicator for Target 15.1

  • Indicator 15.1.2: Proportion of important sites for terrestrial and freshwater biodiversity that are covered by protected areas, by ecosystem type. The article provides the foundational data for this indicator by defining the “important sites” (the 426 freshwater ecoregions) and cataloging their biodiversity. It explicitly notes that freshwater ecosystems are “often underrepresented in designated conservation areas,” and the database allows for a precise analysis of this gap.

• Indicator for Target 15.5

  • Indicator 15.5.1: Red List Index. The article heavily relies on and contributes to the data behind this indicator. It states, “We updated the distributional data for tetrapods… by drawing on the public IUCN Red List database” and also used it for fish. The comprehensive species list helps refine the knowledge base for calculating the Red List Index for freshwater vertebrates.

• Indicator for Target 6.6

  • Indicator 6.6.1: Change in the extent of water-related ecosystems over time. While the article does not measure the physical extent of ecosystems, the FreshVerts v1.0 database serves as a crucial biological baseline. It allows for monitoring the status of biodiversity within these ecosystems, which is an essential component of their overall health and a key aspect of what this indicator aims to track.

• Indicators for Targets 17.16 and 17.18

  • The FreshVerts v1.0 database itself. The existence and public availability of this database, containing “96,129 ecoregional population records representing 23,130 freshwater vertebrate species,” serves as a tangible indicator of a successful multi-stakeholder partnership (17.16) and a significant increase in the availability of high-quality, reliable, and geographically disaggregated data (17.18).

4. Table of SDGs, Targets, and Indicators

Source: nature.com