Oceanic islands provide useful models for ecology, biogeography and evolutionary research. Many discoveries on earth—including Darwin’s theory of evolution—emerged from the study of species on islands and their interactions with their living and nonliving environments.
Today, an international research team led by researchers from the University of Göttingen and the German Center for Integrative Biodiversity Research (iDiv) is examining the flora of the Canary Island of Tenerife. The results are surprising: the plant life of the island shows a remarkable diversity of forms. However, the plants differ little from mainland plants in terms of availability. Unlike the flora of the mainland, the flora of Tenerife is dominated by slow-growing, woody trees with a “low-risk” life strategy. The results were published in NATURE.
Researchers have conducted extensive field research and measurements at more than 500 sites using the latest methods of functional ecology. The sites are scattered throughout the island at altitudes ranging from sea level to mountainous regions above 3,300 meters.
The scientists recorded about 80% of Tenerife’s native plant seeds, and surveyed eight plant characteristics: plant size, specific wood density, leaf thickness, absolute and specific leaf area , leaf dry matter, leaf tissue nitrogen concentration, and seed weight. They compared their data with data on more than 2,000 plant species found on the mainland.
“Our study shows, for the first time and contrary to all expectations, that the groups of species that have evolved in the Canary Islands do not contribute to the expansion of the range of different characteristics. This means that they do not lead to greater diversity in use,” explained the leader of the study, Professor Holger Kreft from Göttingen University.
Previous comparisons have shown that species occurring on islands can be very different from their relatives on the mainland. A well-known example is given by the Galapagos giant tortoise: the species is found only in the Galapagos Islands and, as a result of adaptation to its environmental conditions, is larger than the tortoises from the mainland. The research team expected a similar difference between island and mainland vegetation, but this was not the case.
“However, we found that most of the species followed the island’s climatic limits. Therefore, the medium-sized, woody species developed. It is likely to live with limited resources and a high risk of extinction on the island . That is, they grow slowly. The high functional diversity is mainly due to the species that are widespread on the island and the surrounding land,” explained Kreft.
“At the beginning of our research, we thought that island plants would show fundamental differences and be characterized by limited diversity in terms of function due to their geographic isolation,” explained first author Dr. Paola Barajas Barbosa, who currently works as a researcher at iDiv. The results are part of his doctoral thesis, which he did at the University of Göttingen. “We were very surprised to see that the plants of Tenerife have a relatively high functional diversity.”
Martha Paola Barajas Barbosa et al, Assembly of functional diversity in an oceanic island flora, NATURE (2023). DOI: 10.1038/s41586-023-06305-z
Provided by the University of Göttingen
Citation: Research team compares form and function of island and mainland plants (2023, July 13) retrieved 13 July 2023 from https://phys.org/news/2023-07-team-function-island-mainland .html
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