Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Sep 16;13(1):15353.
doi: 10.1038/s41598-023-42529-9.

Predicting ecosystem changes by a new model of ecosystem evolution

Katsuhiko Yoshida  1 , Kenji Hata  2   3 , Kazuto Kawakami  4 , Syuntaro Hiradate  5 , Takeshi Osawa  6 , Naoki Kachi  3
Affiliations

Predicting ecosystem changes by a new model of ecosystem evolution

Katsuhiko Yoshida et al. Sci Rep. .

Abstract

In recent years, computer simulation has been increasingly used to predict changes in actual ecosystems. In these studies, snapshots of ecosystems at certain points in time were instantly constructed without considering their evolutionary histories. However, it may not be possible to correctly predict future events unless their evolutionary processes are considered. In this study, we developed a new ecosystem model for reproducing the evolutionary process on an oceanic island, targeting Nakoudojima Island of the Ogasawara Islands. This model successfully reproduced the primitive ecosystem (the entire island covered with forest) prior to the invasion of alien species. Also, by adding multiple alien species to this ecosystem, we were able to reproduce temporal changes in the ecosystem of Nakoudojima Island after invasion of alien species. Then, we performed simulations in which feral goats were eradicated, as had actually been done on the island; these suggested that after the eradication of feral goats, forests were unlikely to be restored. In the ecosystems in which forests were not restored, arboreous plants with a high growth rate colonized during the early stage of evolution. As arboreous plants with a high growth rate consume a large amount of nutrient in soil, creating an oligotrophic state. As a result, plants cannot grow, and animal species that rely on plants cannot maintain their biomass. Consequently, many animals and plants become extinct as they cannot endure disturbances by alien species, and the ecosystem loses its resilience. Therefore, even if feral goats are eradicated, forests are not restored. Thus, the founder effect from the distant past influences future ecosystem changes. Our findings show that it is useful to consider the evolutionary process of an ecosystem in predicting its future events.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Schematic figure of the evolution and nutrient cycle of the model ecosystem. The simulation of the model ecosystem starts with one seabird species and one herbaceous plant species. Through frequent speciation within the ecosystem and rare species immigrations, the ecosystem transforms into a more diverse and complex structure. See Appendix 1 for the nutrient cycle process within the ecosystem, and Appendix 2 for details of the evolution process.
Figure 2
Figure 2
Schematic diagram of procedure of a simulation. Immigration: a completely new species immigrates to the ecosystem. Speciation: one species is selected from the constituent species of the ecosystem and given an opportunity for speciation. A subpopulation of the species is separated from the main population of the species and becomes a new species.
Figure 3
Figure 3
An example of changes in a model island ecosystem. (a) Shows the vegetation change from start to 200,000th step (just before invasions of alien species). (b) Shows it during the era of alien species (from 200,000th step to 220,000th step). (c) Shows the changes in biomass of goats and rats. In (a), data are plotted per 1000 time-steps and, in (b) and (c), data are plotted per 100 time-steps (this high-resolution plotting is due to high data fluctuation). In this example, white popinac did not expand. Following the invasion of white popinac, its area remained at less than 0.5%. The biomass of goats and rats rapidly increased after the invasion of these species. However, the biomass of both species soon declined because vegetation of the island declined. After the eradication of goats at the 210,000th time-step, the biomass of rats rapidly increased because rats were freed from competition with goats. The island became fully covered with forests at 216,000 time-steps. The vegetation ratio after that until the end of the simulation (310,000 time-steps) did not change. The plots after 220,000 time-steps, therefore, are omitted.
Figure 4
Figure 4
Comparison between ecosystems restored and not restored the forested state after the eradication of feral goats. “1” indicated by the bold line in each graph means there is no difference between ecosystems restored and not restored the forested state. Levels on the right side of the line indicate that the value of ecosystems not restored is greater than those restored. The values at the right end of the graph were obtained by dividing the values for the unrestored ecosystems by the values for the restored ecosystems. * indicates significance level (****p < 0.0001; ***p < 0.001; **p < 0.01; *p < 0.05). For actual values, see Table A.2.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Caut S, et al. Rats dying for rats: Modelling the competitor release effect. Austral. Ecol. 2007;32:858–868. doi: 10.1111/j.1442-9993.2007.01770.x. - DOI
    1. Raymond B, McInnes J, Dambacher JM, Way S, Bergstrom DM. Qualitative modelling of invasive species eradication on subantarctic Macquarie Island. J. Appl. Ecol. 2011;48:181–191. doi: 10.1111/j.1365-2664.2010.01916.x. - DOI
    1. Bode M, Baker CM, Plein M. Eradicating down the food chain: Optimal multispecies eradication schedules for a commonly encountered invaded island ecosystem. J. Appl. Ecol. 2015;52:571–579. doi: 10.1111/1365-2664.12429. - DOI
    1. Bode M, et al. Revealing beliefs: Using ensemble ecosystem modelling to extrapolate expert beliefs to novel ecological scenarios. Methods Ecol. Evol. 2017;8:1012–1021. doi: 10.1111/2041-210X.12703. - DOI
    1. Baker CM, Gordon A, Bode M. Ensemble ecosystem modeling for predicting ecosystem response to predator reintroduction. Conserv. Biol. 2017;31:376–384. doi: 10.1111/cobi.12798. - DOI - PubMed

Publication types