Seagrass Genetic Diversity Increases In Areas Physically Disturbed By Sea Otters

A new study has learned that eelgrass, a type of seagrass, is more resilient in areas with otters.

A Science report specified that when sea otters are digging for clams in seagrass meadows, they're leaving a "pockmarked moonscape" in their wake, which ecologist at the Hakai Institute, Erin Foster described as "full of craters," just pitting all over the place.

Nonetheless, such a rough treatment may be giving the otherwise lavish meadows a reproductive advantage. On the other hand, according to Boris Worm, a marine ecologist at Dalhousie University, the said discovery is a significant advance.

Worm, who was not part of the work, added that the study showed how large animals might help to maintain actively in the habitat's quality and resistance.

'Eelgrass Seagrass'

A terrestrial plant making its way back into the oceans, seagrass has two methods to reproduce. First, it can clone itself by sending out roots popping up new shoots, inherently identical to the parent plant.

Second, it can sexually reproduce by flowering and scattering seeds. Foster, together with her colleagues, said they were interested in a type of seagrass identified as eelgrass discovered in the North Pacific Oceans' cool waters.

The study authors thought the stress of the otter disturbance might result in the eelgrass flowering more, which it tends to do when stressed and might clear new spots on the seafloor where seedlings could flourish.

In the study published in Science, researchers compared the DNA's sections in more than 460 eelgrass shoots from 15 different meadows off the British Columbia coast.

Otters Comfortably Settling in the Meadows

In six of all the meadows, otters had been comfortably settling for over three decades. In the other six, the animals had been absent for over a century, having never gone back since being wiped out by human hunters. Meanwhile, in the other three meadows, the population of otters had only been reestablished in the past decade.

The analysis' results were quite remarkable that Foster said she repeatedly analyzed, around 20 times. The study investigators found that otters burrowed approximately five percent of meadows where they lived.

Additionally, in the meadows, with long-established populations of otters, eelgrass genetic diversity was a third higher than comparable sites minus otters, as reported by the team.

Such diversity may explain a more remarkable ability to flourish in challenging or changing conditions. According to Worm, "little genetic diversity" is an actual threat because it makes them "inherently vulnerable" to the changes in the environment, including warming waters.

Essentially, genetic diversity can counteract that susceptibility and helps meadows thrive.

Animals Linked to Genetic Diversity

Foster quickly said the result may be considered as a "rediscovery." She also noted that Indigenous Seri people in the Gulf of California have long harvested eelgrass and expected enhanced harvests from more distressed meadows.

Worm said this is some of the first studies to discover the genetic consequences of large animal disturbance, World News Era reported.

He also added that it was fascinating that a species at the top of the food chain, otters, could help change plants' genetic diversity in their habitat, all the way at the food chain's bottom.

The University of California, Santa Barbara ecologist Douglas McCauley said the association between genetic diversity and animals "is novel and exciting." However, he warned that the result does not mean disturbance of ecosystems will always result in more genetic diversity.

In certain circumstances, it could generate the opposite impact. For example, added intense grazing in grasslands could overturn flowering and boost clonal development instead, reducing diversity.

Related information about 'sea grass with and without others' is shown on Edyong209's YouTube video below:

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