Orangutan reintroductions could risk population survival, study warns

An estimated 1,500 orangutans now live in rescue and rehabilitation centers located across Sumatra and Borneo. As habitat loss due to deforestation and forest fires continues, these institutions are struggling to keep up with demand.

Release into the wild is the ultimate, urgent, goal for most of these animals, but a new study warns that there could be serious genetic implications for the offspring of reintroduced animals — and orangutan populations in general — if those rescued from one region are released into a different region.

The study, led by primatologist Graham Banes, examined the genetic consequences when orangutans from different, divergent, subspecies interbreed. Borneo’s three recognized subspecies — from three distinct regions — are thought to have diverged from each other 176,000 years ago, meaning that hybridization between them may result in negative genetic effects. If hybrid offspring reproduce, combinations of genes that were beneficial for one lineage can be disrupted, resulting in poor health and reduced reproductive success, the researcher said. These effects, known as “outbreeding depression,” could threaten the survival of individuals and populations in the long-term.

Read the full article on Mongabay.

A Bornean orangutan in a rehabilitation center in Sabah. Photo by Rhett A. ButlerA Bornean orangutan in a rehabilitation center in Sabah. Photo by Rhett A. Butler

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Dams threaten future of Amazonian biodiversity major new study warns

Amazonia’s surge in hydropower development threatens numerous species with extinction, and puts unique habitats at risk, warns a recent study.

River dolphins, giant otters, turtles, fish, birds and monkeys will all have their habitats altered by hydroelectric dams, with some species likely to be completely wiped out, says an international team of biologists that looked at all impacts associated with 191 existing Amazon dams, as well as the 246 dams being planned or under construction.

What’s more, the researchers identified a network of negative interactions between dam construction, mining, climate change, human migration, and biodiversity and ecosystem services which illustrates how impacts can cascade in multiple, devastating ways.

In environmental terms, the most obvious and direct impact of dams reported by the study are on water flow and connectivity. Nutrients that flow downstream from the Andes are interrupted by dams; flood pulses that form a vital part of many species’ lifecycles are modified by the reservoirs and flow patterns that dams create and control; habitat complexity is lost; and species such as river dolphins become isolated in the stretches of river between hydropower developments, which leaves smaller sub-populations vulnerable to decline.

To read the full article, orginally published on Mongabay, click here.

River turtles in Colombia. Turtles, dolphins and otters are among the aquatic species threatened by dam construction, but risks extend to birds, bats and terrestrial animals too. Photo by Rhett A. ButlerRiver turtles in Colombia. Turtles, dolphins and otters are among the aquatic species threatened by dam construction, but risks extend to birds, bats and terrestrial animals too. Photo by Rhett A. Butler