Animals are disappearing from forests, with grave consequences for the fight against climate breakdown – new research



A toucan eating a fruit in the tropical wetlands of the Pantanal, Brazil.
Uwe Bergwitz/Shutterstock

Charlie Gardner, University of Kent; Jake Bicknell, University of Kent; Matthew Struebig, University of Kent, and Zoe Davies, University of Kent

It’s tempting to think that our forests would be fine if we could simply stop trees being felled or burnt. But forests – particularly tropical ones – are more than just trees. They’re also the animals that skulk and swoop among them.

Worryingly, these furry and feathered companions are rapidly disappearing – and our new research indicates that this will have grave repercussions for the role forests play in combating climate breakdown.

Healthy tropical forests swarm with life. Beyond myriad invertebrates there are seed-eating rodents, a range of leaf eaters, birds of all kinds, and often primates. However, many forests have already lost most of their largest animals, mainly as a result of hunting to supply a growing bushmeat trade.

Hunting isn’t the only reason. Thanks to deforestation for farmland and logging, many forests today are highly fragmented. The small, unconnected patches that remain aren’t big enough to support populations of the largest species, which tend to need more space.

The disappearance of animals from otherwise intact habitats is known as defaunation, and it is leading to a growing number of empty forests not just in tropical countries, but around the world. The UK has already lost most of its largest species (think lynx, wolf, and wisent), while woodland bird numbers have declined by a quarter since 1970.




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The impacts of this defaunation have attracted the attention of the world’s conservation scientists, but studies to date have usually been carried out at single locations. Consequently, we lack a worldwide picture that takes into account different types of forest and the diversity of animals that are disappearing.

To fill this gap, we worked with William Baldwin-Cantello, chief adviser on forests at the World Wide Fund for Nature UK, to gather together all the existing research and perform a meta-analysis – an analysis of analyses – on the available data.

Forest flora need flourishing fauna

Our findings reveal a worrying trend. The loss of animals compromises the ability of forests to reproduce. This effect is particularly severe when primates and birds disappear, because of the key role they play in seed dispersal. Trees make fruit to entice animals to transport their seeds, because they are more likely to germinate and grow successfully if they fall further from their parent tree. So when fruit-eating animals disappear, fewer seeds are dispersed and the trees struggle to reproduce.

A black howler monkey eating a juicy cashew fruit.
akramer/Shutterstock

This animal absence will slowly change how forests look. Most tropical forests today are dominated by trees whose seeds are dispersed by animals. Over time, they are likely to be gradually replaced by trees that use the wind to reproduce. Naturally, these usually have small seeds, and therefore produce smaller trees that store less carbon for the same area of forest. As a result, forests will store less and less carbon, even if we completely halt deforestation.

This is particularly concerning because roughly 20% of the carbon dioxide we emit is absorbed by the world’s vegetation and soils, and half of this is due to tropical forests alone.

Rethinking forest health

Conserving forests is essential for the fight against climate breakdown – and, we do have a global tool at our disposal to help. Known as Reducing Emissions from Deforestation and forest Degradation, or REDD+ for short, it allows wealthy countries with large carbon footprints to pay poorer, tropical countries to protect their forests.

Of course, REDD+ is only an effective tool if the forests countries pay to protect continue to store the same amount of carbon. We usually monitor this by taking satellite images of the quantity of forest canopy remaining. But what satellite imagery can’t do is measure aspects of forest quality beneath the canopy.

Our research strongly suggests that one aspect of forest quality – defaunation – is a vital early warning sign of future losses in the carbon storing capacity of forests. In light of this, policies for managing forest carbon around the world may need a rethink.

We need to pay more attention to what’s going on beneath global forest canopies through research on the ground, though this will be difficult in remote areas. More importantly, we must make sure we’re doing all we can to conserve the full complement of animal species that live in our forests. For example, we need to heavily invest in conservation actions that help communities accustomed to hunting bushmeat to meet their dietary protein needs without harming wildlife. We must also enforce existing rules better, such as those that outlaw hunting within parks and reserves.

Preventing defaunation in forests won’t be easy. But given what we know about the critical role forest animals play, doing so will be essential if we hope to retain diverse and carbon-rich forests in the tropics and around the world. If the beauty and wonder of the forest’s animals wasn’t enough reason to protect them, we now have another: by conserving wildlife, we will be helping to save ourselves from the catastrophic effects of climate breakdown.


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Charlie Gardner, Lecturer in Conservation Biology, University of Kent; Jake Bicknell, Lecturer in Conservation Biology, University of Kent; Matthew Struebig, Senior Lecturer in Biological Conservation, University of Kent, and Zoe Davies, Professor of Biodiversity Conservation, University of Kent

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Mass slaughter of wedge-tailed eagles could have Australia-wide consequences


Simon Cherriman, Murdoch University

Last week it was revealed that at least 136 wedge-tailed eagles have been intentionally poisoned in East Gippsland, with concerns that more are yet to be found.

In the past five years I have used satellite tracking devices to research wedge-tailed eagles’ movements across Australia, and I’ve never encountered raptor deaths on this scale.




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It’s been suggested that the birds were killed to protect lambs. Tragically, not only was this illegal cull unnecessary – evidence suggests that eagles do not often kill livestock – but it could also have ecological consequences right across Australia.

Juvenile birds

There are two main categories of wedge-tailed eagles, based on their age class: sedentary breeding adults, which stay in a home range with nest sites; and highly nomadic juvenile birds that can cover huge distances. There are usually fewer adult birds in one place, because they are territorial.

The very high number of birds affected make it likely that they were largely juveniles. There is currently no accurate data on how many wedge-tailed eagles are in Australia, but this single culling event could have serious effects on future generations’ breeding capacity.




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Sites of persecution can have impacts to eagle populations if they become “ecological sinks”. These are places that draw birds in from a wide area, perhaps because of an unnaturally abundant food source, and then result in birds dying. If these ongoing “mortality black holes” cause hundreds of birds to die in relatively short periods of time, this can start impacting the population.

Do eagles kill lambs?

The wedge-tailed eagle is a powerful predator that kills a variety of mammals. Anecdotal observations by landowners describe birds attacking live lambs and even half-grown sheep. There are also cases in the literature of them working in tandem to hunt larger prey such as kangaroos – behaviour that has been widely documented for large eagle species.

However, evidence gathered during extensive research in Australia has shown that in most cases, eagles seen feeding on lamb or sheep carcasses are “cleaning up” after other predators like foxes and crows, which were actually the direct cause of death.

There are no documented cases of wedge-tailed eagles causing significant economic impacts to the sheep industry. But even if they did, there are other options besides culling. Carcasses placed near livestock would provide easier alternative food sources, for example. Shepherds can effectively guard flocks and protect lambs. Finally, given that wedge-tailed eagles are protected, it may be appropriate for the government to pay compensation for livestock losses.




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It must also be emphasised that eagles prey on a range of other species that are considered to be agricultural pests, such as overabundant native kangaroos, cockatoos, and feral species like rabbits and foxes.

The ConversationSome eagles live, and some die. Such is life on this amazing, arid continent. Death itself is a normal ecological phenomenon, but unnatural deaths on such a large scale can have disastrous consequences for long-lived raptors like the wedge-tailed eagle. We must as a community respect the critical role that predators play in the landscape.

Simon Cherriman, Ornithology, Murdoch University

This article was originally published on The Conversation. Read the original article.

Antarctica and the US Government Shutdown


The link below is to an article that reports on the consequences of the US shutdown in Antarctica.

For more visit:
http://www.treehugger.com/natural-sciences/unprecedented-antarctic-disaster-unfolding-darkness.html

Polar Bears and Climate Change


The link below is to an article that looks at Polar Bears and the consequences of climate change.

For more visit:
http://inhabitat.com/climate-change-is-forcing-polar-bears-to-consume-more-contaminants/

Tasmania: Ocean Warming is Happening


According to a recent report ocean warming is happening off the east coast of Tasmania. The consequences of such warming includes the decline of important kelp forests, fish distribution and changes in fish habitats, and a growing population of destructive sea urchins.

For more visit:
http://www2.utas.edu.au/tools/recent-news/news/cascade-of-climate-change

 

Birds: Feeding Birds not a Good Thing?


Many people love to have native birds visit their gardens. To achieve this we feed birds in a variety of ways. Feeding wild birds does have consequences for the long term survival of the birds being fed. The following link is to an article with more on this subject.

For more visit:
http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2011/Effects-of-Bird-Feeding.aspx