Forests: An Endangered Resource

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Why fruit-eating birds are critical to restoring our dying forests

When birds are restricted, they are not able to spread seeds. This brings a serious decline in the amount of carbon a forest recovers.


A study on the Atlantic Forest region in Brazil reveals that free movement of fruit-eating birds is crucial for restoring tropical forests.

The authors of the study claim that seed dispersal by birds plays a significant role in natural plant regeneration and carbon sequestration, affecting about 70 to 90 percent of tree species.

“Fruit-eating birds such as the Red-Legged Honeycreeper, Palm Tanager, or the Rufous-Bellied Thrush play a vital role in forest ecosystems by consuming, excreting, and spreading seeds as they move throughout a forested landscape,” the researchers note.

However, fragmented landscapes formed within forests because of deforestation, agriculture, poaching, and other human activities restrict the movement of wild birds, reducing their carbon recovery potential to a large extent.

The fragmentation of forests is a big problem. The Atlantic Forest is one of the world’s biggest biodiversity hotspots. It is home to nearly seven percent of all plant species and five percent of all vertebrate species on Earth.

However, it is also one of the most fragmented tropical forests. About 88 percent of its vegetation is lost, and now 12 percent of the original forest is left. The remaining forest is a patchwork of scattered micro-forests, many of which are too far apart from each other to support bird movement.

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They found that in highly fragmented areas where wild tropical birds can’t move freely, the carbon recovery potential dips by up to a staggering 38 percent. It means that forests in such areas can recover only 62 percent of the sequestered carbon lost due to deforestation, wildfire, and other events causing damage to vegetation and biodiversity.

“We have always known that birds are essential, but it is remarkable to discover the scale of those effects. If we can recover the complexity of life within these forests, their carbon storage potential would increase significantly,” Thomas Crowther, senior study author and a professor of Ecology at ETH Zurich, said.

The data from the study also suggest that two forested areas within the large forest shouldn’t be located more than 133 meters (436 feet) away from each other. Otherwise, birds will find it difficult to move across the forests, adversely affecting seed dispersal and pollination activities. This entails that effective forest regeneration must necessarily also include plating new fruit trees to bridge the gaps between fragmented forests.

Interestingly, the size of birds and the seeds they disperse also affect the carbon recovery in forests. For instance, large birds like Toco toucans disperse seeds from trees that have greater carbon storage potential.
However, the large birds can’t help much with forest recovery in highly fragmented landscapes because they don’t fly there. Smaller birds, on the other side, can effectively distribute seeds in fragmented areas but they pick seeds from trees with less carbon storage potential.

This also means that it is the fruit-eating birds that have the most potential for rain forest regeneration.

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https://www.zmescience.com/science/news-science/fruit-eating-birds-forest-restoration/

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Gone in a puff of smoke: 52,000 sq km of ‘long unburnt’ Australian habitat has vanished in 40 years

Landscapes that have escaped fire for decades or centuries tend to harbour vital structures for wildlife, such as tree hollows and large logs. But these “long unburnt” habitats can be eliminated by a single blaze.

The pattern of fire most commonly experienced within an ecosystem is known as the fire regime. This includes aspects such as fire frequency, season, intensity, size and shape.

Fire regimes are changing across the globe, stoked by climate and land-use change. Recent megafires in Australia, Brazil, Canada and United States epitomise the dire consequences of shifting fire regimes for humanity and biodiversity alike.

We wanted to find out how Australian fire regimes are changing and what this means for biodiversity.

In our new research, we analysed the past four decades of fires across southern Australia. We found fires are becoming more frequent in many of the areas most crucial for protecting threatened wildlife. Long unburnt habitat is disappearing faster than ever.

To address this gap, we compiled maps of bushfires and prescribed burns in southern Australia from 1980 to 2021.

We studied how fire activity has changed across 415 Australian conservation reserves and state forests (‘reserves’ hereafter), a total of 21.5 million hectares. We also studied fire activity within the ranges of 129 fire-threatened species, spanning birds, mammals, reptiles, frogs and invertebrates.

We focused on New South Wales, the Australia Capital Territory, Victoria, South Australia and Western Australia because these states and territories have the most complete fire records.

More fire putting wildlife at risk
We found areas of long unburnt vegetation (30 years or more without fire) are shrinking. Meanwhile, areas of recently burnt vegetation (5 years or less since the most recent fire) are growing. And fires are burning more frequently.

On average, the percentage of long unburnt vegetation within reserves declined from 61% to 36% over the four decades we studied. We estimate the total area of long unburnt vegetation decreased by about 52,000 square kilometres, from about 132,000 sq km in 1980 to about 80,000 sq km in 2021. That’s an area almost as large as Tasmania.

At the same time, the mean amount of recently burnt vegetation increased from 20% to 35%. Going from about 42,000 sq km to about 64,000 sq km in total, which is an increase of 22,000 square kilometres.

And the average number of times a reserve burnt within 20 years increased by almost a third.

While the extent of unburnt vegetation has been declining since 1980, increases in fire frequency and the extent of recently burnt vegetation were mainly driven by the record-breaking 2019–20 fire season.

and more:
https://theconversation.com/gone-in-a-puff-of-smoke-52-000-sq-km-of-long-unburnt-australian-habitat-has-vanished-in-40-years-226810