From smartphones to satellites: Uniting crowdsourced biodiversity monitoring and Earth observation to fill the gaps in global plant trait mapping

Abstract

Plant functional traits are fundamental to ecosystem dynamics and Earth system processes, but their global characterization is limited by the availability of field surveys and trait measurements. Recent expansions in biodiversity data aggregation, including large collections of vegetation surveys, citizen science observations, and trait measurements, offer new opportunities to overcome these constraints. Here we demonstrate that combining these diverse data sources with high-resolution Earth observation data enables accurate modeling of key plant traits at up to 1 km resolution. Our approach achieves high predictive power, reaching correlations up to 0.63 (15 of 31 traits exceeding 0.50) and improved spatial transferability, effectively bridging gaps in under-sampled regions. By capturing a broad range of traits with high spatial coverage, these maps can enhance our understanding of plant community properties and ecosystem functioning globally, and can serve as useful tools in modeling global biogeochemical processes and informing worldwide conservation efforts. Ultimately, our framework highlights the power and necessity of crowdsourced biodiversity data in high-resolution plant trait modeling. We anticipate that advancements in biodiversity data collection and remote sensing capabilities will further refine global trait mapping, fostering a dynamic trait-based understanding of the biosphere.

Methodology

Vegetation occurrences from citizen science sources (CIT) and vegetation plot surveys (SCI) were matched with mean trait values by species name with trait databases. This served to produce three training data sets (CIT, SCI, and a combination of the two) used to extrapolate community-level trait values as a function of environmental and Earth observation data. Ensemble gradient-boosting was used for trait modeling.

Earth observation datasets used as predictors include: MODIS surface reflectance, SoilGrids2.0 soil properties, WorldClim Bioclimatic variables, and the Vegetation Optical Depth Climate Archive (VODCA).

Usage Notes

Here you can find maps of 31 plant functional traits as defined in the TRY Plant Trait Database with a resolution of 1 km and a global extent. The maps are extrapolations by ensemble models trained on ~40 million citizen science species observations from the Global Biodiversity Information Facility as well as scientific species abundances recorded in the sPlot database in combination with TRY trait data and global Earth observation datasets.

The current iteration of the trait maps includes traits sourced from plants across three major plant functional types (PFTs): shrubs, trees, and grasses. PFT-specific maps are in progress and will be available soon.

For questions, please contact Daniel Lusk (daniel.lusk [at] geosense.uni-freiburg.de).

These products have been created in the framework of the PANOPS project. More information on this project is available at:

• https://uni-freiburg.de/enr-geosense/research/panops/
• https://gepris-extern.dfg.de/gepris/projekt/504978936?language=en
• Download

Trait descriptions

Plant functional traits used for modeling and trait map generation. "Trait" refers to a shortened version of the "TRY trait name". "TRY trait name" refers to the name used in the TRY trait database.

Trait	TRY trait name	Unit
Conduit element length	Wood vessel element length; stem conduit (vessel and tracheids) element length	µm
Dispersal unit length	Dispersal unit length	mm
LDMC	Leaf dry mass per leaf fresh mass (leaf dry matter content, LDMC)	g g-1
Leaf area	Leaf area (in case of compound leaves: leaflet, undefined if petiole is in- or excluded)	mm2
Leaf C	Leaf carbon (C) content per leaf dry mass	mg g-1
Leaf C/N ratio	Leaf carbon/nitrogen (C/N) ratio	g g-1
Leaf delta 15N	Leaf nitrogen (N) isotope signature (delta 15N)	ppm
Leaf dry mass	Leaf dry mass (single leaf)	g
Leaf fresh mass	Leaf fresh mass	g
Leaf length	Leaf length	mm
Leaf N (area)	Leaf nitrogen (N) content per leaf area	g m-2
Leaf N (mass)	Leaf nitrogen (N) content per leaf dry mass	mg g-1
Leaf P	Leaf phosphorus (P) content per leaf dry mass	mg g-1
Leaf thickness	Leaf thickness	mm
Leaf water content	Leaf water content per leaf dry mass (not saturated)	g g-1
Leaf width	Leaf width	mm
Plant height	Plant height (vegetative)	m
Rooting depth	Root rooting depth	m
Seed germination rate	Seed germination rate (germination efficiency)	days
Seed length	Seed length	mm
Seed mass	Seed dry mass	mg
Seed number	Seed number per reproduction unit	-
SLA	Leaf area per leaf dry mass (specific leaf area, SLA or 1/LMA): undefined if petiole is in- or excluded)	m2 kg-1
SRL	Root length per root dry mass (specific root length, SRL)	cm g-1
SRL (fine)	Fine root length per fine root dry mass (specific fine root length, SRL)	cm g-1
SSD	Stem specific density (SSD) or wood density (stem dry mass per stem fresh volume)	g cm-3
Stem conduit density	Stem conduit density (vessels and tracheids)	mm-2
Stem conduit diameter	Stem conduit diameter (vessels, tracheids)	µm
Stem diameter	Stem diameter	m
Wood fiber lengths	Wood fiber lengths	µm
Wood ray density	Wood rays per millimetre (wood ray density)	mm-1

How to Cite

To cite this dataset, please use the following BibTeX entry:

        @dataset{lusk_global_2025,
            title = {Global plant trait maps based on crowdsourced biodiversity monitoring and Earth observation - 1 km - All {PFTs}},
            url = {https://zenodo.org/records/14646322},
            doi = {10.5281/zenodo.14646322},
            abstract = {Global, high-resolution plant trait maps based on crowdsourced biodiversity monitoring and Earth observation},
            version = {1.0.0},
            publisher = {Zenodo},
            author = {Lusk, Daniel and Wolf, Sophie and Svidzinska, Daria and Kattenborn, Teja},
            urldate = {2025-03-11},
            date = {2025-03-10},
            keywords = {1-km, Citizen science, Earth observation, Functional ecology, Global maps, notion, Plant traits},
            file = {Snapshot:/home/daniel/Zotero/storage/R396Z8PR/14646322.html:text/html},
        }

Related Work

• TRY Trait Database
• Global Biodiversity Information Facility
• sPlot