Fate of meerkats tied to seasonal climate effects

Fate of meerkats tied to seasonal climate effects

The effects of climate change are especially obvious in arid environments where resources are scarce and subject to seasonal availability. However, the demographic mechanisms through which seasonal climate affects population persistence remains mostly unknown. Using detailed monthly life-history data collected by the Kalahari Meerkat Project between 1997 and 2016, scientists at the Universities of Zurich and Cambridge have now assessed how meerkats (Suricata suricatta) will fare in response to future changes in seasonal rainfall and temperature.

Meerkats are cooperative breeders that live in social groups. A dominant female monopolizes most of the reproduction, while subordinate helpers assist in raising her offspring. Changes in the physical and social environment affect the growth, survival and reproduction of meerkats. For example, wet and warm conditions at the beginning of summer increase the growth, survival and mreproduction of these animals. In contrast, high population densities and cold weather during winter decrease individual growth and survival.

Seasonal dynamics atter

The Kalahari Desert in Southern Africa is projected to become drier and warmer as a result of climate change. The new study investigates how consistently rising summer temperatures and rainfall fluctuations will affect body mass and growth of meerkats, resulting in lower rates of reproduction and offspring survival. However, this isn’t the only finding of the study.

“In addition to the common practice of modeling average annual dynamics, we took a closer look at seasonal dynamics and developed a specific climate change model,” says Maria Paniw of the Department of Evolutionary Biology and Environmental Studies at the University of Zurich. “We found that the picture is more complex: Seasonality matters because improving conditions in one season can partially counter the worsening conditions in the next season.”

Hotter winters can alleviate negative effects

The team linked changes observed in growth, survival and reproduction to changes in seasonal rainfall and temperature. Using these links in a population projection model, the scientists projected the population dynamics 50 years into the future, creating different scenarios based on a report on climate change issued by US National Center for Atmospheric Research (NCAR).

The data shows that the combined effects of hotter and drier summers in particular may threaten the persistence of the meerkat population. In the study’s projections, fewer offspring were produced, resulting in fewer helpers in the population. In this scenario, the meerkat population plummeted, increasing the risk of population collapse.

In contrast, the negative effects of less rainfall in summer would be alleviated to an extent if winters became warmer, allowing meerkats to gain weight and step up reproduction. Taking these counteracting seasonal changes into account leads to a different scenario, in which the probability of extinction is less severe and the meerkats would still persist in 50 years.

Link between seasonality and populations dynamics

“The effect of an environmental change on a population depends on how individuals interact with their biological and physical environment, and how these interactions will change over time. Our study demonstrates that we have to accurately identify these interactions, especially in terms of how these interactions vary between seasons, to predict a population’s vulnerability in the face of climate change,” says Arpat Ozgul, senior author of the study and professor of population ecology at the Department of Evolutionary Biology and Environmental Studies at the University of Zurich.

Professor Tim Clutton-Brock, co-author from the University of Cambridge and founder of the Kalahari Meerkat Project, adds: “Our work emphasizes the importance of long-term, individual-based studies that extend over several decades. Only where data of this kind is available is it possible to assess the effects of climate change on animal populations and to understand the ecological mechanisms re-sponsible for them.”

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How economic theory and the Netflix Prize could make research funding more efficient

How economic theory and the Netflix Prize could make research funding more efficient

As scientific funding becomes increasingly scarce, professors in STEM fields spend more time in their offices writing grant applications: by one estimate, as much as one-fifth of their research time. That takes time and energy away from teaching students, training young researchers and making discoveries that boost our collective knowledge and well-being.

Two scientists believe that, with professors vying for such a small pool of funds, the grant-application process has become a competition not over who has the best ideas, but who is the best at writing grant applications. In a paper published Jan. 2 in the journal PLOS Biology, co-authors Carl Bergstrom, a professor of biology at the University of Washington, and Kevin Gross, a professor of statistics at North Carolina State University, use the economic theory of contests to illustrate how this competitive system has made the pursuit of research funding inefficient and unsustainable. They show that alternative methods, such as a partial lottery to award grants, could help get professors back in the lab where they belong.

To receive a grant today, professors apply to funding agencies like the National Science Foundation or the National Institutes of Health. Reviewers evaluate and rank the applications, and the highest-ranking applications receive grant funding.

But over time, the percentage of proposals that receive funding has dropped dramatically. This is largely because the pool of available funds has not grown to keep pace with the number of STEM researchers.

“Back in the 1970s, the top 40 to 50 percent of applications to agencies were funded,” said Bergstrom. “Agencies merely had to separate the good research plans from the bad based on the grant applications.”

Funding thresholds for grant applications have tightened steadily since the 1970s. In 2003, only the top 20 percent of research project grant applications to the National Institute of Allergy & Infectious Diseases were funded. In 2013, the success rate had plummeted to 8 percent. Gross and Bergstrom argue that the funding pool has grown so small relative to the number of applicants that the nature of the grant-application process had changed.

“When agencies only fund the top 10 or 20 percent, they aren’t just separating bad ideas from good ideas,” said Bergstrom. “They’re also separating good from good.”

“This has two effects on the grant-application process,” said Gross. “First, professors must apply for more and more grants before they’re awarded one. Second, the application process becomes a contest to determine who can write the best grant proposals — so professors spend more and more time trying to perfect each individual application.”

Gross and Bergstrom realized that today’s grant-application process can be described using the economic theory of contests. In contest theory, teams compete to produce a product or complete a task for an agency; the agency picks a winner and retains the fruits of the team’s efforts, while the winning team receives a prize such as cash. For the Netflix Prize, for example, teams competed to produce an algorithm that would predict how users would rank films on its streaming service. Netflix received the winning algorithm, while the winning team pocketed $1 million.

“If we were to apply contest theory to grants, then professors are the ones competing to create a product — the best grant application — for the agency,” said Gross. “That’s not a particularly good system, though, because the funding agency doesn’t want grant applications for their own sake. They want to fund research.”

In their paper, Bergstrom and Gross illustrate how the grant-application process is consistent with economic contest models. They show how funding a relatively small fraction of grant applications — such as the top 10 or 15 percent — makes the practice of science inefficient: The negative costs associated with trying to produce the best grant application could potentially outweigh the economic value of the science produced.

If agencies funded a higher percentage of applications, professors could spend less time trying to write the perfect grant application. In addition, funding agencies wouldn’t have to subjectively choose winners among high-quality proposals that are all based on sound science. But this option would require significantly expanding funding to agencies like the NIH and the NSF, a politically difficult task.

Using the economic theory of contests, Gross and Bergstrom modeled a controversial alternative: awarding grants instead by partial lottery. Under a partial lottery system, funds are awarded by random draw among a pool of high-ranking grants — the top 40 percent, for example. Since applicants would be aiming to clear a lower bar for a smaller prize — a shot at the lottery instead of a guaranteed payout for winning proposals — the contest theory model predicts that applicants would spend less time trying to perfect their applications, Bergstrom said.

Partial lotteries have been proposed by others, such as UW professor of laboratory medicine Ferric Fang and Johns Hopkins professor Arturo Casadevall. They’re also used by two funding agencies in New Zealand and the Volkswagen Foundation. Gross and Bergstrom simply use contest theory to show how this system could also free professors from the seemingly endless cycle of grant applications.

But partial lotteries aren’t the only viable solution, they say. Funding agencies could also award grants based on merit, such as a professor’s past record of excellence in research. But that system also would need mechanisms to help early-career faculty and professors from underrepresented groups obtain grants, Bergstrom said. Hybrid systems are another option, such as a partial lottery for early-career faculty and merit-based grants for later-career faculty.

“There are many potential routes out of the current hole,” said Bergstrom. “What doesn’t change is our conclusion that the current grant-application system is fundamentally inefficient and unsustainable.”

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Plant hormone makes space farming a possibility

Plant hormone makes space farming a possibility

With scarce nutrients and weak gravity, growing potatoes on the Moon or on other planets seems unimaginable. But the plant hormone strigolactone could make it possible, plant biologists from the University of Zurich have shown. The hormone supports the symbiosis between fungi and plant roots, thus encouraging plants’ growth — even under the challenging conditions found in space.

The idea has been bounced around for a while now — and not just by the likes of NASA, but also by private entrepreneurs such as Jeff Bezos and Elon Musk: that of one day establishing colonies for people to live on the Moon or on other planets. Such visions, as well as the prospect of long-term human space expeditions in the future, raise the question of how to sustainably provide food for the people in space. One possible answer is to cultivate crops in situ. However, the soils on the Moon and on other planets are surely lower in nutrients compared to our agricultural land. The alternative — transporting nutrient-rich soil and fertilizers up into space — comes with a high economic and ecological cost.

Plant-fungal symbiosis promotes plant growth

When looking for a possible solution, the research group working with Lorenzo Borghi of the University of Zurich and Marcel Egli of the Lucerne University of Applied Sciences and Arts concentrated on the process of mycorrhiza, a symbiotic association between fungi and plant roots. In this symbiosis, the fungal hyphae supply the plant roots with additional water, nitrogen, phosphates and trace elements from the ground. In return they get access to sugar and fat produced by the plant. This symbiosis is stimulated by hormones of the strigolactone family, which most plants secrete into the soil around their roots. The process of mycorrhization can greatly increase plant growth and thereby substantially improve crop yields — especially in soil that is low in nutrients.

Absence of gravity impedes mycorrhization

In space, cultivated plants would not just have to contend with low-nutrient soil, but also with conditions of microgravity, i.e. almost zero gravity. In order to investigate the influence of such an environment on plant growth, the researchers cultivated petunias and mycorrhizal fungi under simulated low gravity conditions. Petunias provide a model organism for plants of the nightshade family (Solanaceae), which include for example tomatoes, potatoes and eggplants.

The experiments revealed that microgravity hindered the mycorrhization and thus reduced the petunias’ uptake of nutrients from the soil. But the plant hormone strigolactone can counteract this negative effect. Plants that secreted high levels of strigolactone and fungi which the researchers had treated with a synthetic strigolactone hormone were able to thrive in the low-nutrient soil despite the microgravity conditions.

Best practice for food production in space

“In order to get crops such as tomatoes and potatoes to grow in the challenging conditions of space, it is necessary to encourage the formation of mycorrhiza,” summarizes research leader Lorenzo Borghi. “This seems to be possible using the strigolactone hormone. Our findings may therefore pave the way for the successful cultivation in space of the types of plants that we grow on Earth.”

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‘Spartan Fist’ is a first-person brawler with blocky cartoon violence

‘Spartan Fist’ is a first-person brawler with blocky cartoon violence, ,

The world of good first-person indie games is a small one, and beat-em-ups are similarly scarce. Spartan Fist, then may be the brightly-colored first-person puncher you’ve been waiting for. Glass Bottom Games’ third major game stars detective Emma Jo…

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