Biodiversity and Tree Population: More Intense Farming is Better, Researchers Say

You would think that deforestation eliminates bird's homes and inevitably reduces species' populations. However, according to a recent study, it's better to farm more intensively in some areas and leave more blocks untouched, in order to better preserve bird species richness.

"I think the most surprising result is that species richness within communities does not explain the loss of phylogenetic diversity under land-sharing," David Edwards, of the University of Sheffield, said in a news release. "So even if farming at low intensity over a larger area retains the number of species present, those species are less evolutionarily distinct and thus preserve less phylogenetic diversity."

Researchers examined the Chocó-Andes of Colombia, a biological corridor with many diverse birds species, including a number that can't be found anywhere else in the world. Unfortunately, it is also an area threatened by widespread cattle pastures.

The researchers decided on three study areas, each of witch contained contiguous forests and cattle farms. Contiguous farming is a method of adjoining or adjacent farm lands being used for the same crop production. In these areas, the researchers sampled bird populations.

What did they find? They found that many birds living in areas where there was not a lot of farming had a loss of more than 650 million years of evolutionary history, compared to forested areas, the release noted.

"The Chocó-Andes are a hotspot of endemism and have been widely impacted by low-intensity farming, making this one of the most threatened faunas on Earth," Edwards said. "It is vital to consider how best to farm here, but also to use this region as a model for how best to farm in other locations."

To better understand the relationship between birds and farming practices, the team of researchers used landscape simulations. In doing so, they were able to compare the outcomes of land-sharing to land-sparing practices--which can be compared to suburban and urban land uses, respectively. The researchers found that the more widespread forests were, land-sharing became less beneficial to bird populations. This isolation observed in land-sharing communities also lead to a loss of more evolutionary distinct species within that area, the researchers noted. In order to maintain the same crop yield and protect species biodiversity, farmers can instead set aside land to be conserved.

"Land-sharing policies that promote the integration of small-scale wildlife-friendly habitats might be of limited benefit without the simultaneous protection of larger blocks of natural habitat, which is most likely to be achieved via land-sparing measures," the team concluded. However, there is a long road ahead for the implementation and wide spread use of land-sparing techniques, in order to better protect natural habitats.

Their findings were recently published in the Cell Press journal Current Biology.

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