A lonely tree makes plenty of friends

Posted on 29 July, 2021 by Ivan

Connecting Country has long advocated for raising awareness of paddock trees and their importance in providing habitat in a disconnected landscape. To the credit of many local farmers and landholders, we often see paddock trees spared from cropping and clearing, allowing them to support many species of birds, insects and arboreal mammals. You can find a number of blogs we’ve published over the years on how to manage paddock and lonely trees – click here and here.

We recently discovered a great article published on The Conversation, which highlights why and how lone trees can be managed in the landscape to support wildlife to move through agricultural landscapes. The article covers examples and research in a number of countries and concludes that lone trees are vital to provide wildlife stepping stones between healthy patches of habitat. Please see the published article below courtesy of The Conversation. We would love to see some photos of your favourite lone trees in the landscape!

A lone tree in a paddock in Guildford, providing important refuge for travelling wildlife. Photo: Ivan Carter

A lone tree makes it easier for birds and bees to navigate farmland, like a stepping stone between habitats

Vast, treeless paddocks and fields can be dangerous for wildlife, who encounter them as “roadblocks” between natural areas nearby. But our new research found even one lone tree in an otherwise empty paddock can make a huge difference to an animal’s movement.

We focused on the Atlantic Forest in Brazil, a biodiversity hotspot with 1,361 different known species of wildlife, such as jaguars, sloths, tamarins and toucans. Habitat loss from expanding and intensifying farmland, however, increasingly threatens the forest’s rich diversity of species and ecosystems. We researched the value of paddock trees and hedges for birds and bees, and found small habitat features like these can double how easily they find their way through farmland.

This is important because enabling wildlife to journey across farmlands not only benefits the conservation of species, but also people. It means bees can improve crop pollination, and seed-dispersing birds can help restore ecosystems.

Connecting habitats

Lone trees in paddocks, hedges and tree-lined fences are common features of farmlands across the world, from Brazil to Australia.

They may be few and far between, but this scattered vegetation makes important areas of refuge for birds and bees, acting like roads or stepping stones to larger natural habitats nearby. Scattered paddock trees, for instance, offer shelter, food, and places to land. They’ve also been found to create cooler areas within their canopy and right beneath it, providing some relief on scorching summer days.

Hedges and tree-lined fences are also important, as they provide a safe pathway by providing hiding places from predators. For our research, we used satellite images of the Atlantic Forest and randomly selected 20 landscapes containing different amounts of forest cover.

We then used mathematical models to calculate the habitat connectivity of these landscapes for three groups of species — bees, small birds such as the rufous-bellied thrush, and large birds such as toucans — based on how far they can travel. And we found in areas with low forest cover, wildlife is twice as likely to move from one natural habitat to another if paddock trees and hedges can be used as stepping stones.

We also found vegetation around creeks and waterways are the most prevalent and important type of on-farm habitat for wildlife movement. In Brazil, there are legal protections for these areas preventing them from being cleared, which means vegetation along waterways has become relatively common compared to lone trees and hedges, in places with lower forest cover.

Insights for Australia

For example, in Australia, many koala populations depend on scattered trees for movement and habitat. In 2018, CSIRO researchers in Queensland tracked koalas using GPS, and found koalas used roadside vegetation and scattered trees for feeding and resting significantly more than they expected. Likewise, lone trees, hedges and tree-lined fences can also facilitate the movement of Australian fruit-eating birds such as the Olive-backed Oriole and the Rose-crowned Fruit Dove. Improving habitat connectivity can help these birds travel across landscapes, feeding and dispersing seeds as they go.

In fragmented landscapes, where larger patches of vegetation are hard to find, dispersing the seeds of native plants encourages natural regeneration of ecosystems. This is a key strategy to help achieve environmental restoration and conservation targets.

To read the full article, please click here.