Species loss varies significantly under different climate change scenarios


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Insects were found to be more susceptible to climate change than other land animals and plants. (Joe Hatfield/flickr)

Jenna Ladd | May 24, 2018

According to a recent study published in the journal Science, limiting global warming to 1.5 degrees Celsius above preindustrial levels rather than 2 degrees Celsius could significantly reduce terrestrial plants and animal species loss.

The study analyzed the geographic habitat ranges of 100,000 land plant and animal species, including insects. Scientists monitored how suitable habitat ranges changed under three climate change scenarios: the 1.5 degrees Celsius warming limit goal set by the Paris Climate Accord, a 2 degrees Celsius increase and the 3.2 degrees Celsius increase Earth is expected to experience by 2100 if no further climate action is taken.

They found that if global warming is held at 2 degrees Celsius, 18% of insects, 16% of plants and 8% of vertebrates will lose more than half of their suitable habitat range. In contrast, if global temperature increase is kept under 1.5 degrees Celsius, just 6% of insects, 8% of plants and 4% of vertebrates would experience the same fate.

Rachel Warren is an environmental biologist at the University of East Anglia in Norwich, England and one of the study’s others. She said to the Los Angeles Times, “All the previous scientific literature looked at 2 degrees as the lower limit because that was what was being discussed at the time.” Warren continued,”The takeaway is that if you could limit warming to 1.5 degrees, the risk to biodiversity is quite small. At 2 degrees it becomes significant, and at 3 degrees almost half the insects and plants would be at risk.”

Of note, the study found that insects were more sensitive a warming climate than vertebrates and plants. For example, the typical insect under the 3 degrees Celsius warming condition would lose 43 percent of its habitat range.

Hymenoptera declared to be the most species rich animal order


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A parasitic wasp pauses on a leaf (Katja S/flickr)

Eden DeWald| May 23rd, 2018

University of Iowa professor Andrew Forbes has been conducting research that may intimidate those who aren’t fans of parasitic wasps. Forbes specializes in studying these wasps that belong to the Hymenoptera order, which also includes insects such as bees and ants.

In a preprint paper, meaning it has not yet been peer reviewed, Forbes asserts that the Hymenoptera order is more species rich than originally thought. Previously, Coleoptera— the beetle order, was thought to be the most speciose. However, Forbes’ specialization in parasitoid wasps allowed him to make the connection that there can be multiple species of parasitic wasps preying upon a single species of insect. Based on this ratio, one species of host insect to many different species of parasitic wasps, it would make sense that Hymenoptera is the most species rich order. The paper concludes that Hymenoptera has perhaps 2.5-3.2 times more species rich than Coleoptera.

Species richness is an important factor in general biodiversity. And although parasitic wasps may sound quite gruesome, they can provide useful services. Parasitic wasps prey on insects that are bothersome to humans such as garden pests like caterpillars, and even mosquitoes.

Important factors in preserving biodiversity on coffee plantations


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Black coffee beans begin as red cherry-like fruits on a tree. (Coffee Management Services/flickr)

Jenna Ladd | April 19, 2018

As final exams loom closer, many students may find themselves relying a little too heavily on coffee to get them by. But what is the relationship between the black midnight oil and biodiversity?

There are two distinct coffee plants that produce the stuff that fills students’ mugs: coffee arabica and coffee robusta. Arabica plants provide fuel for the coffee connoisseur as its flavor is know for being smoother, richer and more nuanced than coffee robusta. The two plants require different growing conditions, too. Arabica does well in areas that are partly shaded by surrounding canopy while robusta grows better in cleared out areas with more sun.

Researchers from the Wildlife Conservation Society, Princeton University and the University of Wisconsin-Madison sought to determine whether there was a difference in impacts on biodiversity between the two plants. They collected bird species biodiversity data from coffee plantations in Western Gnats, India between 2013 and 2015. Some of the plantations grew arabica coffee while others grew robusta. Those areas producing arabica had roughly 95 percent canopy tree cover, and those areas growing robusta had 80 percent canopy tree cover. Shockingly, however, this had little effect on bird biodiversity. The difference between the number of species each of the areas supported was not significant.

“An encouraging result of the study is that coffee production in the Western Ghats, a global biodiversity hotspot, can be a win-win for birds and farmer,” said lead author Charlotte Chang to SIERRA magazine.

The story is not the same on a global scale, however. It has become increasingly popular for coffee farmers in South America and other parts of Asia to clear-cut forests around coffee plantations to make harvesting easier and increase plant productivity.

Researchers suggest that coffee consumers take more time to consider in what conditions their cup of joe was grown. If coffee is labeled Rainforest Alliance Certified or Bird Friendly, it is likely have had less of a negative impact on land use and biodiversity.

Warmer temperatures make milkweed toxic for monarchs


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A monarch caterpillar scoots across a common milkweed leaf. (USFWSmidwest/flickr)

Jenna Ladd | April 6, 2018

A recent study published in the journal Ecology uncovered an unexpected consequence of climate change for monarch butterflies.

Researchers from Louisiana State University and University of Michigan set out to understand how warmer temperatures affect the relationship between monarch butterflies and milkweed plants. The insects, whose population has declined by more than 80 percent in the last decade, lay their eggs exclusively on milkweed plants. After the larvae hatch, they feed on certain species of milkweed, which provide protection to the butterflies. Milkweed plants produce chemicals called cardenolides in their leaf tissues, which are poisonous to most of the monarch’s predators. When monarchs consume the perfect amount of these chemicals as larvae, it sends a signal to larger predators to stay away from them.

However, scientists found that as regional temperatures rise, some species of milkweed plants produce more cardenolides. This poses a threat to the monarchs’ survival. One of the researchers, Dr. Bret Elderd, an associate professor at Louisiana State University, explained, “It’s a Goldilocks situation for monarch butterflies. Too few of these chemicals in the milkweed, and the plant won’t protect monarch caterpillars from being eating. But too high of a concentration of these chemicals can also hurt the monarchs, slowing caterpillar development and decreasing survival.”

One species of milkweed by the Latin name of A. curassavica has naturally high levels of cardenolides in its leaves and is especially sensitive to rising temperatures. Landscapers and environmentalists alike have been planting more of the nonnative plant to save the monarchs, but scientists warn that this plan may have backfired. They are working to spread the word that the native variety of milkweed, A. incarnata, has naturally lower levels of cardeolides and is much less likely to become toxic to monarchs as the climate warms.

The study reads, “It has become increasingly recognized that species interactions, especially interactions between tightly-linked species, need to be considered when trying to understand the full impacts of climate change on ecological dynamics.”

The full report can be found here.

Biodiversity declining worldwide


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The sun sets over one of the most biologically diverse areas in the world, the Amazon Rainforest. (Anna & Michael/flickr)

Jenna Ladd | March 30, 2018

Biodiversity, or the overall variety of life forms on Earth, is decreasing substantially in every region of the world due to land use change and climate change.

A compilation of four new United Nations scientific studies, which were recently approved by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), details the loss. Over three years, researchers assessed biodiversity and ecosystem services in the Americas, Asia, the Pacific, Africa and Europe. They found that biodiversity and nature’s ability to provide for humans’ basic needs has declined in every region due to habitat loss overexploitation and unsustainable use of natural resources, pollution, increasing numbers of invasive species and climate change.

In the Americas, the studies found that species richness is about thirty percent less than it was when Europeans first arrived on the continent, and the rate of biodiversity loss in that region seems to be speeding up. They report that under “business as usual” circumstances, 40 percent of the region’s biodiversity will be lost by 2050. While land use and population growth plays a larger role in other regions of the world, climate change is the primary driver behind species loss in the Americas. Given that the natural world provides an estimated $24 trillion per year in ecosystem services to humans in the Americas alone, biodiversity loss is not a concern reserved only for environmentalists.

Protection of key biodiversity areas in the Americas increased by 17 percent between 1970 and 2010. However, the authors point out that these efforts fall short as less than 20 percent of crucial biodiversity areas in the Americas are currently protected.

Sir Robert Watson is the chair of IPBES, he said,

“Biodiversity and nature’s contributions to people sound, to many people, academic and far removed from our daily lives. Nothing could be further from the truth – they are the bedrock of our food, clean water and energy. They are at the heart not only of our survival, but of our cultures, identities and enjoyment of life. The best available evidence, gathered by the world’s leading experts, points us now to a single conclusion: we must act to halt and reverse the unsustainable use of nature – or risk not only the future we want, but even the lives we currently lead. Fortunately, the evidence also shows that we know how to protect and partially restore our vital natural assets.”

To read more about the types of biodiversity loss in other areas of the world, click here.

Climate change alters forest composition


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Sugar maples are seeing population decreases across the U.S. due to climate change, making fiery autumn leaves harder to find. (Mark K./flickr)
Jenna Ladd | February 28, 2017

Beech trees are crowding out other important tree species in northeastern United States woodlands because of climate change, according to a recent study.

Researchers from the University of Maine tracked beech, sugar and red maple tree data in the northeastern U.S. from 1983 to 2014. The U.S. Forest Service data showed that beech tree populations have increased significantly over the thirty years while the other tree species decreased. The study found that hotter temperatures and increased precipitation, both caused my climate change, allowed for beech trees’ population boom.

Beech trees have important advantages over the species that used to dominate the area. First, they often shade out other species competing for sunlight. Second, the local deer prefer the taste of sugar and red maple saplings to beech ones. The changing climate is changing the composition of forests and managers will have to adapt, researchers say.

Dr. Aaron Weiskittel is a forest biometrics and modeling professor at University of Maine and one of the study’s authors. “There’s no easy answer to this one,” he said to the Associated Press, “It has a lot of people scratching their heads. Future conditions seem to be favoring the beech, and managers are going to have to find a good solution to fix it.”

Sugar maples, one of the important species declining in the northeastern U.S., are also expected to decline in numbers in the northern Midwest due to climate change. A twenty-year study published in January found that as global temperatures continue to rise, sugar maple growth in the northern Midwest will be stunted and the species population will decrease.

Researchers point out that forests soak up 25 percent of the greenhouse gases that are emitted each year, so continuing to learn about how forests will respond to the changing climate should be prioritized.

USDA: 95% of Iowa corn is genetically engineered


Cedar Falls cornfield. Photo by Parshotam Lal Tandon; Flickr
Cedar Falls cornfield. Photo by Parshotam Lal Tandon; Flickr

New data released by the US Department of Agriculture shows that 95 percent of Iowan field corn is genetically modified, compared to 93 percent nationally.

Genetically engineered corn includes herbicide tolerant (HT), insect resistant (Bt), and stacked gene varieties that are genetically altered to serve specific purposes. HT crops are designed to survive exposure to specific herbicides, Bt crops are toxic to particular insects, and stacked gene crops have both traits.

Concerns have been raised about various negative consequences of genetically modified organisms (GMOs), including loss of biodiversity and corporate control of agricultural resources.

The report comes in the wake of a recently introduced bill that would increase market regulation and federal control of GMOs. The bill has since been referred to the Subcommittee on Health.