Friday, September 11, 2020

Thursday, September 10, 2020

Ecology: Conservation and food system changes needed to bolster biodiversity

Trees, shrubs and debris are burned on the Canadian prairies to make  way
for more cropland. A PinP photo.

Nature

Declines in terrestrial biodiversity from habitat conversion could be reversed by adopting a combination of bold conservation methods and increases in the sustainability of the food system, a modelling study published in Nature suggests.

Human pressures, such as the destruction of natural habitats to make way for agriculture and forestry, are causing rapid declines in biodiversity, and placing at risk the ecosystem services upon which we depend. Ambitious targets for biodiversity have been proposed, but it is unclear how these targets can be achieved whilst retaining the ability to feed a growing population. Using land-use and biodiversity models, David Leclère and colleagues show how this is possible. 

Conservationists need to increase the amount of actively managed land, restore degraded land and adopt generalized landscape-level conservation planning. Meanwhile, we need to eat fewer animal-derived calories, waste less food and find ways to intensify food production sustainably.

If this double-pronged strategy is followed, more than two thirds of future biodiversity losses from habitat conversion could be avoided, the authors suggest. However, they caution that other threats, such as climate change, must also be addressed to truly reverse biodiversity declines.

"Live fast. Die young!" Fast-growing trees could store less carbon

Nature Communications

Faster growth leads to a shorter lifespan in trees, according to a paper published in Nature Communications. The findings could have implications for predictions of how much carbon forests can store under climate change.
A black spruce (Picea mariana) forest.
Photo credit - Western Arctic National Parklands
A relationship between faster tree growth rates and shorter tree lifespan has been shown in some trees, particularly in cold-adapted conifers, but whether this applies across species and climates has been disputed. Such a trade-off would be at odds with the use of tree growth rates as a proxy for carbon storage, and cast doubt on Earth system model predictions of global forest carbon storage.

Roel Brienen and colleagues analysed a large dataset of tree-ring data representing 110 tree species across all continents except Africa and Antarctica. They report that faster growth is linked to reduced tree lifespan both across and within tree species, and show that this is not due to covariance with climate or soil variables. Using model forest simulations based on data about the black spruce (Picea mariana), they further show that this trade-off has the potential to slow down or even reverse the global forest carbon sink in the future.

These findings challenge most predictions of future carbon storage in mature forests, casting doubt on the persistence of the global forest carbon sink in the coming decades. The authors call for efforts to integrate tree-growth lifespan trade-offs in process-based models of forest carbon dynamics.

Tuesday, September 8, 2020

Arctic ocean moorings shed light on winter sea ice loss

Science Daily
A table iceberg in the Norwegian Arctic. Such icebergs are rare
as they calve from shelf ice, which is also rare. They're normally
a typical form of iceberg in the Antarctic. This one is about 12m high
and about half the size of a soccer field. Photo by Andreas Weith.




















The eastern Arctic Ocean's winter ice grew less than half as much as normal during the past decade, due to the growing influence of heat from the ocean's interior, researchers have found. Story here.


Monday, September 7, 2020

Meet the Canadian farmers fighting climate change

The Narwhal
Conservation and agriculture have often been at odds. But as Ottawa develops the first federal carbon offset standard, farming techniques that reduce greenhouse gas emissions are having a moment. Story here.

RELATED:
Here's another farmer who fits the category described, above.
Zack Koscielny is a fifth generation farmer located near Strathclair,
Manitoba implementing regenerative agriculture practices on his farm.
He has a degree in Agroecology and is a graduate of the Soil Health Academy.

YET ANOTHER HEAT WARNING