'Greedy' trees leave enough "crumbs" for little plants to eke out a living

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London, July 7 (ANI): A new research has indicated that although trees might hog the bulk of the resources, they still leave enough "crumbs" for smaller neighbouring plants to eke out a living.

The finding contradicts previous notions of plant competition and adds support to a new view of how a plant's size affects the survival and composition of its neighbouring species.

Previously, it was assumed that trees and other large plants monopolized sunlight, water, and other available resources, limiting the number of smaller plant species that can coexist in their vicinity.

Research in greenhouse settings supported this view.

Now, according to a report in New Scientist, a study of forests in southern British Columbia shows that larger plants do not always correlate with fewer species in an area.

Laura Keating and Lonnie Aarssen of Queen's University in Ontario, Canada, targeted nearly 160 plants of various species and sizes, ranging from wild rose bushes to Ponderosa pines, counting the number of species present beneath their canopies.

As a control, the team compared those numbers with the average number of species in randomly selected patches in each plant's habitat.

They found that for larger and larger trees, the ratio of the number of species beneath their canopies to the number expected in an average random patch stayed more or less the same.

In other words, the size of the tree had little effect on the number of species that coexist with it.

According to Aarssen, small plants in the understory of larger plants feast on the "crumbs" of sunlight, water, and soil nutrients that their hosts cannot exploit.

"The bigger it gets, the less efficiently a plant uses available resources," said Aarssen.

He thinks this leaves niches available for species better adapted to small spaces.

Keating and Aarssen did find that trees tended to have fewer nearby species than small bushes, which they think is caused by the loss of shade-intolerant species.

Once the canopy reaches a few square metres in size, however, the species richness beneath it stays relatively constant for larger and larger canopies.

Abella said that this new work adds to a changing view of competition in the field of plant ecology.

"A lot of these concepts about competition aren't really held by ecologists anymore. It's about facilitation," he said.

Abella explained that many plants derive an advantage by living underneath their larger and more resource-intensive neighbours. (ANI)

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