Rediscovering biodiversity: using big-data to trace taxonomic knowledge through time

Project Information

TAXON-TIME

Grant agreement ID: 843234

DOI

10.3030/843234

Project closed

EC signature date 12 April 2019

Start date 1 December 2019

End date 2 May 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 172 932,48

EU contribution

€ 172 932,48

Coordinated by

AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Spain

Periodic Reporting for period 1 - TAXON-TIME (Rediscovering biodiversity: using big-data to trace taxonomic knowledge through time)

Reporting period: 2019-12-01 to 2021-11-30

Summary of the context and overall objectives of the project

TAXON-TIME investigated how advances in taxonomy affect macroecological patterns of species richness and composition in tropical rainforests.

Throughout centuries, taxonomists have been describing new species and revising, in light of new information, their taxonomic delimitation and classification. Advances in taxonomy often result in the lumping of several species into one, the splitting of a “single” species into several species, or re-assigning a species to a distinct genus.

The resulting fluctuations in the identity and number of species have important implications for global biodiversity research and conservation. This is particularly true for tropical ecosystems. Due to the enormous biodiversity of tropical rainforests, changes in the taxonomy of tropical plants can introduce considerable uncertainty into global estimates of species richness and predictions of how tropical flora may respond to global warming or deforestation.
Yet, fluctuations in the identity and number of species due to progress in taxonomy have remained so far functionally invisible for macroecology – the science that explains patterns of species richness, composition and abundance across broad spatial and evolutionary scales. TAXON-TIME project addressed this problem.

The project revealed that taxonomic progress were crucial for shaping the current pattern of species richness and composition in the whole Neotropical region and in the Amazonian rainforest. More specifically, we observed that the well-documented geographic pattern of species richness and composition only emerge as a result of past taxonomic changes.

TAXON-TIME also brought to light the debate about how patchy progress in taxonomy complicates global estimates of species richness. The results of the project challenged such estimates, reinforcing the idea that a single, universally accepted estimate of the number of species on Earth may never be achieved (Stropp et al. 2022). The project has stressed that quantifying uncertainty in estimates of species richness that emerge from taxonomy is a major scientific challenge – one that needs to be tackled by an interdisciplinary collaboration of taxonomists, macroecologists, and data scientists working across multiple taxa in different continents.

TAXON-TIME highlighted that understanding macroecological patterns of tropical rainforests needs to go hand in hand with deepening our knowledge about species taxonomy.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Work during the project has concentrated on four fronts: (1) compiling a database with taxonomic descriptions and reclassifications of tropical plants, (2) performing quality checks on the data compiled, (3) documenting the timeline of taxonomic changes, and (4) analysing temporal and geographic trends in species description and reclassifications. The project was carried out at the Spanish Natural Science Museum (MNCN-CSIC; hosting institution) the and University of Luxembourg (Secondment)

Database: As of June 2022, the database T4-DB contains bibliographic information and the timeline of nomenclatural changes for 3 935 taxa belonging to the families Arecaceae, Lecythidaceae (Amazon rainforest) or the clade Bignonieae (Neotropics). For Bignonieae, we added detailed information about attributes of species descriptions, whereas for Arecaceae we added information about characteristics (e.g. functional traits and phylogenetic. The database (Arecaceae, Lecythidaceae, Bignonieae) will be made publicly available via Digital CSIC upon publications derived from TAXON-TIME (Stropp et al. in prep. and Meyer et al. in prep).

Results: The database compiled by TAXON-TIME provided the basis for quantifying the contribution of taxonomic change to established patterns of species richness and composition of tropical rainforests. Two analyses on subsets of this database (Bignonieae and Arecaceae) reveal that 78% of all descriptions of Neotropical Bignonieae (Bignonieae) proposed taxa names that later became synonyms, while for Amazonian palms (Arecaceae) the share of synonyms is 85%. Synonymizations were crucial for shaping the current pattern of species richness and composition. For Bignonieae, the well-documented pattern of species richness, i.e. high richness in the Amazon and the Atlantic forests decreasing towards central South America and the subtropical region, is only observed due to past taxonomic changes (Meyer et al. in prep.). For Amazonian palms, the established geographical pattern of changes in species composition, which stretches from northeast Amazonia to the southeast portion of the Brazilian Amazon also only emerges as a result of taxonomic changes that occurred mainly after the 1990s (Stropp et al. in prep). Together, these results show that progress in taxonomy can modify the observed correlations between different aspects of biodiversity (e.g. species richness and composition) and environmental factors, such as climate or soil fertility.

Finally, TAXON-TIME results show that synonymization is not random across taxa. In fact, synonyms are more frequent in earlier described taxa, in taxa that were subject to intensive taxonomic investigation and those with large geographical ranges.
TAXON-TIME will continue to expand the database documenting taxonomic changes of tropical plants to include other plant groups. Thanks to an 18-month extension of this MSCA action funded by the Spanish National Research Council, the fellow will proceed with her studies on the impact of taxonomic progress on macroecological patterns of tropical plants.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Our understanding of the impact of taxonomic change on patterns of plant species richness and composition has been so far largely based on generalizations from other biological groups (mainly vertebrates) or theoretical assumptions derived from simulated data. TAXON-TIME provided the first empirical account and quantification of such impact on tropical plants. The project has revealed regions in the Neotropics and in the Amazon rainforest where changes in species richness and composition have been pronounced as a result of taxonomic progress and taxa for which circumscriptions have often been challenged. TAXON-TIME went one step further and revealed the factors associated with taxonomic changes, namely the year of first taxonomic description, taxonomic effort, and size of the area of occupancy of species.

TAXON-TIME has shown it can take centuries to achieve a stable taxonomic classification and delimitation. Yet, solid knowledge of species taxonomy underpins any robust ecological analysis.

For taxonomists, ecologists, and conservationists, time matters. While the taxonomy of several tropical plants remains uncertain, deforestation and climate change continue to threaten biodiversity. Deepening our understanding of plant taxonomy in the tropics has never been so challenging. Limited research budget hampers the establishment of long-term research projects and land conflict increasingly poses a risk to field expeditions. The societal implication of this concatenated series of caveats is enormous. We risk losing species before they are (accurately) described, thus being left with uncertain ecological findings of how tropical biodiversity originated and how it is being affected by global change. We either increase our efforts to document biodiversity or we will watch deforestation eroding many unknown habitats and species in our lifetimes.

Canopy view of the Amazon rainforest. Photo credits: Peter van de Sleen