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. 2025 Feb 25;122(8):e2415104122.
doi: 10.1073/pnas.2415104122. Epub 2025 Feb 18.

Global diversity and energy of animals shaping the Earth's surface

Affiliations

Global diversity and energy of animals shaping the Earth's surface

Gemma L Harvey et al. Proc Natl Acad Sci U S A. .

Abstract

The collective influence of animals on the processes shaping the Earth's surface remains largely unknown, with most studies limited to individual species and well-known exemplars. To establish the global geomorphic significance of animals, we systematically reviewed and synthesized evidence across freshwater and terrestrial ecosystems. Over 600 animal taxa had reported geomorphic effects. For the 495 wild animals and 5 livestock identified to species level, we estimated their global abundance, and collective biomass and energy. While our census is global in scope, a lack of research in the tropics and subtropics, and on less visible animals, leaves them underrepresented in analyses. Most reported species are globally widespread, but some are rare, endemic, and/or threatened, leading to risks that key geomorphic processes cease before we fully understand them. We estimate the collective biomass in wild animal geomorphic agents at ≈0.2 Mt Carbon, equating to a biological energy content of ≈7.6 million GJ. If a conservative minimum 1% of this energy contributes to geomorphic work annually, this yields an energy contribution from wild animal geomorphic agents of ≈76,000 GJ-equivalent to the energy of hundreds of thousands of extreme floods. Uncertainties in biomass estimates and energy partitioning mean this value could credibly be an order of magnitude higher, and countless species remain unreported or undiscovered. The livestock estimates exceed the wild animals estimates by three orders of magnitude. The geomorphic energy of animals is far more influential than previously recognized and future losses, dispersal and introductions of zoogeomorphic species may induce substantive landscape changes.

Keywords: biogeomorphology; ecosystem engineers; landforms; landscape evolution.

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Conflict of interest statement

Competing interests statement:The authors declare no competing interest.

Figures

Fig. 1.
Fig. 1.
Global diversity, range and conservation status of reported zoogeomorphic species, and types of zoogeomorphic effect. (A) Number of zoogeomorphic species identified from published literature (filled circle = a species) color-coded by taxonomic class, with circles scaled by research attention (number of papers). (B) Proportion of reported wild species studied in native/non-native ranges and (C) conservation status of reported species. (D) Zoogeomorphic landforms and processes identified within terrestrial and freshwater ecosystems, filled circle scaling reflects number of species linked with that effect. Some species may be associated with multiple effect types (e.g., burrows and mounds, or dens and diggings) but each species is only represented once for each type of effect. Classifications are primarily based on descriptions and terminology provided in the original published studies (Materials and Methods).
Fig. 2.
Fig. 2.
Global distribution, abundance, and richness of reported zoogeomorphic agents. (A) Distribution of occurrence records for terrestrial and freshwater species. (B) Frequency distribution of global occurrence records for reported zoogeomorphic species, grouped by genera, colored by taxonomic class. (C) Global patterns in species abundance (occurrence density) of reported zoogeomorphic agents and (D) global patterns in species richness of reported zoogeomorphic agents. Maps (C) and (D) are based on GBIF occurrence records for wild animal species. Livestock distributions captured in GBIF data are presented in SI Appendix, Fig. S3.
Fig. 3.
Fig. 3.
Classification of genera containing zoogeomorphic species based on genus size, proportion of reported zoogeomorphic agents, and taxonomic characteristics. Groups are organized by ecosystem and total genus size: Each filled circle represents a genus (n = 362), scaled by the number of zoogeomorphic species in that genus. Genera are color-coded by taxonomic class. Representative animals are shown by icons.
Fig. 4.
Fig. 4.
Range of estimates for the energy of zoogeomorphic species available for geomorphic work annually. Values represent an estimated minimum of 1% of total biological energy. Size of each circle reflects the number of zoogeomorphic species in that group. Estimates for different taxonomic groups are compared to example geomorphological disturbances (river floods, monsoons, and total annual energy of mountain slope processes) from the literature (SI Appendix, Table S4). The livestock estimate is shown in gray and was calculated using published biomass estimates for the five reported zoogeomorphic livestock species.
Fig. 5.
Fig. 5.
Distribution of research attention (number of publications) by country and study locations for field-based studies (n = 435 papers). Silhouettes of characteristic zoogeomorphic species are shown by region (non-native species are displayed in red).

Comment in

  • Behold the scale of global zoogeomorphic activity.
    Francis RA. Francis RA. Proc Natl Acad Sci U S A. 2025 Mar 18;122(11):e2501894122. doi: 10.1073/pnas.2501894122. Epub 2025 Mar 10. Proc Natl Acad Sci U S A. 2025. PMID: 40063815 Free PMC article. No abstract available.

References

    1. Reinhardt L., Jerolmack D., Cardinale B. J., Vanacker V., Wright J., Dynamic interactions of life and its landscape: Feedbacks at the interface of geomorphology and ecology. Earth Surf. Process. Landf. 35, 78–101 (2010).
    1. Jones C. G., Lawton J. H., Shachak M., Organisms as ecosystem engineers. Oikos 69, 373–386 (1994).
    1. Butler D. R., Zoogeomorphology: Animals as Geomorphic Agents (Cambridge University Press, 1995).
    1. Albertson L. K., Sklar L. S., Cooper S. D., Cardinale B. J., Aquatic macroinvertebrates stabilize gravel bed sediment: A test using silk net-spinning caddisflies in semi-natural river channels. PLoS One 14, e0209087 (2019). - PMC - PubMed
    1. Rice S. P., Pledger A., Toone J., Mathers J., Zoogeomorphological behaviours in fish and the potential impact of benthic feeding on bed material mobility in fluvial landscapes. Earth Surf. Process. Landf. 44, 54–66 (2019).

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