Category Archives: Ecosystems

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Guam Provides A Glimpse Of A Future Without Seed Dispersing Animals

“You couldn’t conduct an experiment to demonstrate how birds affect dispersal and tree regeneration because you can’t experimentally keep birds out of large areas. But the situation on Guam provides a unique accidental experiment. It’s the only place in the world that has lost all frugivores. The difference between Guam and nearby islands is stark, which makes it an extreme example, but these sorts of changes are likely happening to some degree all over the world. (Click on title for full story.)

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Even Amazonia Was Shaped By Ancient Human Agriculturists

The Amazon has long been held up as an example of untamed wilderness. But people have lived in the world’s largest rainforest for thousands of years, hunting, gathering and farming1. For years, researchers have debated how much of an influence human activities have had on the Amazon. And now, a study describes the extent to which ancient peoples changed the distribution of trees in the forest around them. (Click on title for full story.)

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Urban Forests Can’t Restore Themselves Without Human Help

Native tree recruitment…required localized burning and herbivore exclusion,” the authors note. Burning eliminated competing plants and keeping rodents and deer away from the seedlings allowed them to grow. “The damage done by white-tailed deer is well-documented,” Whereas wildland forests have been studied extensively, less is known about an urban system. “If a forest isn’t replacing itself, it’s a garden, Just standing back and letting trees grow is not going to work.” (Click on title for full story.)

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Seagrass Meadows Protect Corals And Marine Animals From Our Filth

Our results indicated that seagrass meadows significantly reduce bacterial loads and can benefit both humans and other organisms in the environment. Represented on every continental shelf but Antarctica, seagrasses are valued for nutrient cycling, sediment stabilization, reduc ing the effects of carbon dioxide elevation, and providing nursery habitat for fisheries.Our observation of reduced levels of coral disease on reefs adjacent to seagrass meadows offers independent support of the benefits that seagrass meadows provide to controlling pathogenic bacteria in marine environments. (Click on title for full story.)

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Devastated Rain Forests Aren’t Just Going To Restore Themselves

The results of the research have implications for the restoration of rainforests: “It is highly unlikely that the tree species we studied is able to recolonise cleared patches in a fragmented habitat by natural seed dispersal alone,” says Kettle. He adds that the same applies to other endangered species of tropical tree with large fruit and seeds dispersed by birds, as evidence from other fragmented tropical forests around the world shows that seeds of this kind are dispersed only locally. “For rainforest restoration projects to be successful, you have to give special attention to these trees,” says Kettle. “If you want to encourage them to spread, the only option is to collect their seeds, set up tree nurseries and then actively plant out the saplings at a later stage.” (Click on title for full story.)

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Coastal Wetlands Uniquely Valuable To Slow Climate Change

All told, coastal wetlands may capture and store more than 200 metric tons of carbon per year globally. Importantly, these ecosystems store 50-90 percent of this carbon in soils, where it can stay for thousands of years if left undisturbed. “When we destroy coastal wetlands, for coastal development or aquaculture, we turn these impressive natural carbon sinks into additional, significant human-caused greenhouse gas sources,” (Click on title for full story.)

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Discovering A Huge Carbon Sink Hidden Under Our Very Feet

Peat is usually associated with cold places, not the middle of the hot, humid, Congo Basin. It’s an organic wetland soil made of partially-decomposed plant debris. In waterlogged places those plants can’t entirely decompose, and are not respired as carbon dioxide into the atmosphere. The peat thus builds up slowly, locking up ever-more carbon. The amounts involved are huge: peat covers just 3% of Earth’s land surface, but stores one-third of soil carbon. We knew that peat can be formed under some tropical swamp forests. Might the world’s second largest tropical wetland, known as the Cuvette Centrale, overlie peat? (Click on title for full story.)

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Longest-lived Tree Species Defends Itself Against Deadly Pine Beetle

Great Basin bristlecone pine has the longest lifespan of any non-clonal organism worldwide. We found that mountain pine beetle, a native insect which has killed millions of pine trees in the past decade, is not attracted to Great Basin bristlecone pine. (Click on title for full story.)

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Good Intentions Gone Bad: Pollinator Seed Mixes Spread Invasive Weeds

We don’t have any issues at all with the concept behind the pollinator habitat program; it’s a good program. But as a result of this program, we’ve now introduced Palmer amaranth to potentially thousands of acres of land, and we need to know what we are going to be allowed to do to try to stem the spread of it. And we need to do that quickly. (Click on title for full story.)

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Local Forest Die-Offs Have Far Reaching Effects (All Forests Are Global)

The new study describes how major forest losses can alter global climate by shifting the path of large-scale atmospheric waves or changing the amount of sunlight absorbed in the Northern versus the Southern hemispheres. Such changes can shift tropical rain bands and other climate features. (Click on title for full story.)