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A geometric basis for surface habitat complexity and biodiversity

Abstract

Structurally complex habitats tend to contain more species and higher total abundances than simple habitats. This ecological paradigm is grounded in first principles: species richness scales with area, and surface area and niche density increase with three-dimensional complexity. Here we present a geometric basis for surface habitats that unifies ecosystems and spatial scales. The theory is framed by fundamental geometric constraints between three structure descriptors—surface height, rugosity and fractal dimension—and explains 98% of surface variation in a structurally complex test system: coral reefs. Then, we show how coral biodiversity metrics (species richness, total abundance and probability of interspecific encounter) vary over the theoretical structure descriptor plane, demonstrating the value of the theory for predicting the consequences of natural and human modifications of surface structure.

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Fig. 1: Increasing fractal dimension (that is, space filling) while keeping surface rugosity constant results in a decline in a surface’s mean height range.
Fig. 2: Comparison of the geometric theory with field data.
Fig. 3: The geometric diversity of coral reef habitats.
Fig. 4: Geometric-biodiversity coupling of coral reef habitats.

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Data availability

Source data for statistical analyses and figures are available at https://github.com/jmadinlab/surface_geometry.

Code availability

Code for data preparation, statistical analyses and figures is available at https://github.com/jmadinlab/surface_geometry.

References

  1. Pimm, S. L. et al. The biodiversity of species and their rates of extinction, distribution, and protection. Science 344, 1246752 (2014).

    Article  CAS  Google Scholar 

  2. Newbold, T. et al. Global effects of land use on local terrestrial biodiversity. Nature 520, 45–50 (2015).

    Article  CAS  Google Scholar 

  3. Alvarez-Filip, L., Dulvy, N. K., Gill, J. A., Côté, I. M. & Watkinson, A. R. Flattening of Caribbean coral reefs: region-wide declines in architectural complexity. Proc. Biol. Sci. 276, 3019–3025 (2009).

    Article  Google Scholar 

  4. Millennium Ecosystem Assessment Ecosystems and Human Well-Being: Synthesis (Island Press, 2005).

  5. Schulze, E. D. & Mooney, H. A. Biodiversity and Ecosystem Function (Springer, 1993).

  6. Pimm, S. L. The complexity and stability of ecosystems. Nature 307, 321–326 (1984).

    Article  Google Scholar 

  7. Morse, D. R., Lawton, J. H., Dodson, M. M. & Williamson, M. H. Fractal dimension of vegetation and the distribution of arthropod body lengths. Nature 314, 731–733 (1985).

    Article  Google Scholar 

  8. McCoy, E. D. & Bell, S. S. in Habitat Structure: the Physical Arrangement of Objects in Space (eds Bell, S. S. et al.) 3–27 (Springer, 1991).

  9. Beck, M. W. Separating the elements of habitat structure: independent effects of habitat complexity and structural components on rocky intertidal gastropods. J. Exp. Mar. Biol. Ecol. 249, 29–49 (2000).

    Article  CAS  Google Scholar 

  10. Kovalenko, K. E., Thomaz, S. M. & Warfe, D. M. Habitat complexity: approaches and future directions. Hydrobiologia 685, 1–17 (2012).

    Article  Google Scholar 

  11. Arrhenius, O. Species and area. J. Ecol. 9, 95–99 (1921).

    Article  Google Scholar 

  12. MacArthur, R. H. & Wilson, E. O. The Theory of Island Biogeography (Princeton Univ. Press, 1967).

  13. Mandelbrot, B. B. The Fractal Geometry of Nature (W. H. Freeman, 1983).

  14. Tokeshi, M. & Arakaki, S. Habitat complexity in aquatic systems: fractals and beyond. Hydrobiologia 685, 27–47 (2012).

    Article  Google Scholar 

  15. Johnson, M. P., Frost, N. J., Mosley, M. W. J., Roberts, M. F. & Hawkins, S. J. The area-independent effects of habitat complexity on biodiversity vary between regions. Ecol. Lett. 6, 126–132 (2003).

    Article  Google Scholar 

  16. Chesson, P. Mechanisms of maintenance of species diversity. Annu. Rev. Ecol. Syst. 31, 343–366 (2000).

    Article  Google Scholar 

  17. Pianka, E. R. Evolutionary Ecology (Harper and Row, 1988).

  18. Sugihara, G. & May, R. M. Applications of fractals in ecology. Trends Ecol. Evol. 5, 79–86 (1990).

    Article  CAS  Google Scholar 

  19. Jones, C. G., Lawton, J. H. & Shachak, M. Positive and negative effects of organisms as physical ecosystem engineers. Ecology 78, 1946–1957 (1997).

    Article  Google Scholar 

  20. Brown, J. H. et al. The fractal nature of nature: power laws, ecological complexity and biodiversity. Phil. Trans. R. Soc. B 357, 619–626 (2002).

    Article  Google Scholar 

  21. Graham, N. A. J. & Nash, K. L. The importance of structural complexity in coral reef ecosystems. Coral Reefs 32, 315–326 (2013).

    Article  Google Scholar 

  22. Madin, J. S. et al. Cumulative effects of cyclones and bleaching on coral cover and species richness at Lizard Island. Mar. Ecol. Prog. Ser. 604, 263–268 (2018).

    Article  Google Scholar 

  23. Hurlbert, S. H. The nonconcept of species diversity: a critique and alternative parameters. Ecology 52, 577–586 (1971).

    Article  Google Scholar 

  24. Hata, T. et al. Coral larvae are poor swimmers and require fine-scale reef structure to settle. Sci. Rep. 7, 2249 (2017).

    Article  Google Scholar 

  25. Madin, J. S. & Connolly, S. R. Ecological consequences of major hydrodynamic disturbances on coral reefs. Nature 444, 477–480 (2006).

    Article  CAS  Google Scholar 

  26. Alvarez-Filip, L. et al. Drivers of region-wide declines in architectural complexity on Caribbean reefs. Coral Reefs 30, 1051–1060 (2011).

    Article  Google Scholar 

  27. Allouche, O., Kalyuzhny, M., Moreno-Rueda, G., Pizarro, M. & Kadmon, R. Area-heterogeneity tradeoff and the diversity of ecological communities. Proc. Natl Acad. Sci. USA 109, 17495–17500 (2012).

    Article  CAS  Google Scholar 

  28. Paxton, A. B., Pickering, E. A., Adler, A. M., Taylor, J. C. & Peterson, C. H. Flat and complex temperate reefs provide similar support for fish: evidence for a unimodal species-habitat relationship. PLoS ONE 12, e0183906 (2017).

    Article  Google Scholar 

  29. Huston, M. A. Patterns of species diversity on coral reefs. Annu. Rev. Ecol. Syst. 16, 149–177 (1985).

    Article  Google Scholar 

  30. Loke, L. H. L., Todd, P. A., Ladle, R. J. & Bouma, T. J. Creating complex habitats for restoration and reconciliation. Ecol. Eng. 77, 307–313 (2015).

    Article  Google Scholar 

  31. Young, G. C., Dey, S., Rogers, A. D. & Exton, D. Cost and time-effective method for multi-scale measures of rugosity, fractal dimension, and vector dispersion from coral reef 3D models. PLoS ONE 12, e0175341 (2017).

    Article  CAS  Google Scholar 

  32. Friedman, A., Pizarro, O., Williams, S. B. & Johnson-Roberson, M. Multi-scale measures of rugosity, slope and aspect from benthic stereo image reconstructions. PLoS ONE 7, e50440 (2012).

    Article  CAS  Google Scholar 

  33. Weiher, E. & Keddy, P. A. Ecological Assembly Rules: Perspectives, Advances, Retreats (Cambridge Univ. Press, 2001).

  34. Bartholomew, A., Diaz, R. J. & Cicchetti, G. New dimensionless indices of structural habitat complexity: predicted and actual effects on a predator’s foraging success. Mar. Ecol. Prog. Ser. 206, 45–58 (2000).

    Article  Google Scholar 

  35. Strain, E. M. A. et al. Eco-engineering urban infrastructure for marine and coastal biodiversity: which interventions have the greatest ecological benefit? J. Appl. Ecol. 55, 426–441 (2018).

    Article  Google Scholar 

  36. Dubuc, B., Zucker, S. W., Tricot, C., Quiniou, J. F. & Wehbi, D. Evaluating the fractal dimension of surfaces. Proc. R. Soc. Lond. A Math. Phys. Sci. 425, 113–127 (1989).

    CAS  Google Scholar 

  37. Zhou, G. & Lam, N. S.-N. A comparison of fractal dimension estimators based on multiple surface generation algorithms. Comput. Geosci. 31, 1260–1269 (2005).

    Article  Google Scholar 

  38. Johnson‐Roberson, M. et al. High‐resolution underwater robotic vision‐based mapping and three‐dimensional reconstruction for archaeology. J. Field Robot. 34, 625–643 (2017).

    Article  Google Scholar 

  39. Pizarro, O., Friedman, A., Bryson, M., Williams, S. B. & Madin, J. A simple, fast, and repeatable survey method for underwater visual 3D benthic mapping and monitoring. Ecol. Evol. 7, 1770–1782 (2017).

    Article  Google Scholar 

  40. Mahon, I., Williams, S. B., Pizarro, O. & Johnson-Roberson, M. Efficient view-based SLAM using visual loop closures. IEEE Trans. Robot. 24, 1002–1014 (2008).

    Article  Google Scholar 

  41. Bryson, M. et al. Characterization of measurement errors using structure‐from‐motion and photogrammetry to measure marine habitat structural complexity. Ecol. Evol. 7, 5669–5681 (2017).

    Article  Google Scholar 

  42. Zawada, D. G. & Brock, J. C. A multi-scale analysis of coral reef topographic complexity using Lidar-derived bathymetry. J. Coast. Res. 10053, 6–15 (2009).

    Article  Google Scholar 

  43. Bivand, R. S., Pebesma, E. & Gómez-Rubio, V. Applied Spatial Data Analysis with R (Springer, 2013).

  44. Wood, S. N., Pya, N. & Säfken, B. Smoothing parameter and model selection for general smooth models. J. Am. Stat. Assoc. 111, 1548–1563 (2016).

    Article  CAS  Google Scholar 

  45. R Core Team R: A Language and Environment For Statistical Computing (R Foundation for Statistical Computing, 2019).

Download references

Acknowledgements

We thank A. Hoggett and L. Vail of the Lizard Island Research Station for their support. This work was supported by an Australian Research Council Future Fellowship (to J.S.M.), the John Templeton Foundation (to M.A.D. and J.S.M.), a Royal Society research grant and a Leverhulme Fellowship (to M.A.D.), an International Macquarie University Research Excellence Scholarship (to D.T.-P.), two Ian Potter Doctoral Fellowships at Lizard Island (to D.T.-P. and V.B.) and an Australian Endeavour Scholarship (to T.J.C.).

Author information

Authors and Affiliations

Authors

Contributions

J.S.M., D.T.-P., M.A.D. and O.P. conceptualized the study. J.S.M. and O.P. developed the theory and J.S.M. ran the analyses. J.S.M., D.T.-P. and O.P. developed the software pipeline for the data and produced the visualizations. J.S.M., D.T.-P., M.A.D. and O.P. led the investigation. J.S.M. and M.A.D. led and funded the broader project, with additional field robotics resources provided by O.P. and S.W. D.T.-P., M.A.D., O.P., M.B., S.A.B., N.B., V.B., T.J.C., G.F., A.F., M.O.H., S.W., K.J.A.Z. and J.S.M. collected the data. J.S.M. wrote the first draft of the paper and all authors reviewed at least one draft.

Corresponding author

Correspondence to Joshua S. Madin.

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Extended data

Extended Data Fig. 1

Differences in fractal dimension when calculated empirically versus from the theory that assumes self-similarity across scales.

Extended Data Fig. 2 Geometric theory for surface habitats.

a, Schematic showing mean height variation as a function of scale. ΔH is the height range of the habitat surface for the extent L. ΔH0 is the mean height range of the surface at the smallest scale: the resolution L0. The two slopes S represent fractal dimensions D of 2 and 3 according to Eq. 2. For example, high D results when mean height ranges at the scale of the grain are large (that is, in the vicinity of ΔH), suggesting a highly convoluted surface. Conversely, low D occurs when mean height variations at the scale of the grain are very small, suggesting an approximately flat surface. b, Area A0 at the scale of the grain L0 is calculated as the minimum surface area given the mean height range at this scale.

Extended Data Fig. 3 Underlying empirical data and models fits (±95% confidence intervals) for all combinations of the three surface descriptors (x-axes) and species richness, abundance and diversity (PIE) (y-axes).

The overall pattern was captured by both statistical approaches: generalised additive models and linear models with second-order polynomials for each surface descriptors. r2 values were consistently better for GAMs and reported here and in Extended Data Fig. 8.

Extended Data Fig. 4

The 21 shallow reef flat locations (black points) and the large Trimodal plot (red box) at Lizard Island, the Great Barrier Reef, Australia.

Extended Data Fig. 5 Digital elevation models of the 21 reef sites capturing different habitats encircling Lizard Island (see Extended Data Fig. 4 for map).

The models show the 2 m by 2 m reef patches (white squares) and depth gradience from 1.5m (lightest green) to 5m depth (darkest blue).

Extended Data Fig. 6 The relationship between R when calculated from the geometric theory for habitat surfaces and when calculated using surface area calculated using a spatial statistics function.

Dashed line is the unity line. Black line is the fit of a linear model (intercept: 0.023 ± 0.007 95% confidence intervals; slope: 1.014 ± 0.046 95% confidence intervals which encapsulates 1).

Extended Data Fig. 7 Model parameter and smooth term estimates for the best-fit species richness (a), abundance (b) and diversity (PIE) GAMs (c).

N =255.

Extended Data Fig. 8 Adjusted r2 values for GAM models of species richness (a), total abundance (b) and diversity (PIE) (c) with each of the three geometric variables and the best combined model after model selection.

N = 255.

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Torres-Pulliza, D., Dornelas, M.A., Pizarro, O. et al. A geometric basis for surface habitat complexity and biodiversity. Nat Ecol Evol 4, 1495–1501 (2020). https://doi.org/10.1038/s41559-020-1281-8

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