Balance of nature: amazing new ecosystem found (Introduction)

by David Turell , Tuesday, January 19, 2021, 15:43 (1404 days ago) @ David Turell

Australian monitor lizard burrows are a hotel for hoards of life:

https://www.sciencenews.org/article/monitor-lizards-huge-burrow-systems-shelter-small-a...

Meters below the copper, sun-broiled dirt of northwestern Australia, an entire community hides in the dark. Geckos lay their eggs as centipedes and scorpions scuttle by. A snake glides deeper underground, away from the light. This subterranean menagerie is capitalizing on an old burrow, gouged into the earth by a massive lizard.

Now, a new study shows that two different species of Australian monitor lizard dig arrays of these burrows into the earth and that the openings have a great impact on local biodiversity, providing shelter to a surprisingly wide assortment of animal life. The findings, published December 18 in Ecology, indicate that the lizards are “ecosystem engineers,” akin to beavers that flood streams with dams or seabirds that fertilize reefs with their guano, the researchers say.

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The team found arthropods, snakes, toads and other lizards in the nests of yellow-spotted monitors and sand goanna monitors (Varanus gouldii), which dig similar burrows. At first it was a few creatures here and there, Doody says, but then the team found 418 Uperoleia frogs in a single warren. In all, the team found nearly 750 individuals of 28 different vertebrate species in a combination of 16 warrens made up of many individual nesting burrows and a handful of foraging burrows, made when the lizards dig for prey.

Some animals are using the burrows for overwintering, Doody says. Others use them as refuges when the creatures need to go dormant during the hot dry summer. Still others catch prey in there, while “some are probably hiding from predators. And some are even laying their eggs in the burrow.”

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Given the widespread use of the burrows by wildlife, Doody has concerns about the broader ecological effects of the ongoing cane toad invasion in Australia’s tropical north. Monitor lizards — naïve to the toads’ potent toxins — will eat the amphibians, with lethal consequences. As a result, monitors are rapidly dying, Doody says, and their warrens are filling in, leaving less refuge for other animals using the burrows. “You go from hundreds of animals using a warren system to zero.”

Comment: Most ecosystems are important but happen accidently. And as in our other discussion, poison is deadly at the wrong times.