Tag Archives: plants

Climate change requires new conservation models, Stanford scientists say

In a world transformed by climate change and human activity, Stanford scientists say that conserving biodiversity and protecting species will require an interdisciplinary combination of ecological and social research methods.

By Ker Than

A threatened tree species in Alaska could serve as a model for integrating ecological and social research methods in efforts to safeguard species that are vulnerable to climate change effects and human activity.

In a new Stanford-led study, published online this week in the journal Biological Conservation, scientists assessed the health of yellow cedar, a culturally and commercially valuable tree throughout coastal Alaska that is experiencing climate change-induced dieback.

In an era when climate change touches every part of the globe, the traditional conservation approach of setting aside lands to protect biodiversity is no longer sufficient to protect species, said the study’s first author, Lauren Oakes, a research associate at Stanford University.

“A lot of that kind of conservation planning was intended to preserve historic conditions, which, for example, might be defined by the population of a species 50 years ago or specific ecological characteristics when a park was established,” said Oakes, who is a recent PhD graduate of the Emmett Interdisciplinary Program in Environment and Resources (E-IPER) at Stanford’s School of Earth, Energy, & Environmental Sciences.

But as the effects of climate change become increasingly apparent around the world, resource managers are beginning to recognize that “adaptive management” strategies are needed that account for how climate change affects species now and in the future.

Similarly, because climate change effects will vary across regions, new management interventions must consider not only local laws, policies and regulations, but also local peoples’ knowledge about climate change impacts and their perceptions about new management strategies. For yellow cedar, new strategies could include assisting migration of the species to places where it may be more likely to survive or increasing protection of the tree from direct uses, such as harvesting.

Gathering these perspectives requires an interdisciplinary social-ecological approach, said study leader Eric Lambin, the George and Setsuko Ishiyama Provostial Professor in the School of Earth, Energy, & Environmental Sciences.

“The impact of climate change on ecosystems is not just a biophysical issue. Various actors depend on these ecosystems and on the services they provide for their livelihoods,” said Lambin, who is also  a senior fellow at the Stanford Woods Institute for the Environment.

“Moreover, as the geographic distribution of species is shifting due to climate change, new areas that are currently under human use will need to be managed for biodiversity conservation. Any feasible management solution needs to integrate the ecological and social dimensions of this challenge.”

Gauging yellow cedar health

The scientists used aerial surveys to map the distribution of yellow cedar in Alaska’s Glacier Bay National Park and Preserve (GLBA) and collected data about the trees’ health and environmental conditions from 18 randomly selected plots inside the park and just south of the park on designated wilderness lands.

“Some of the plots were really challenging to access,” Oakes said. “We would get dropped off by boat for 10 to 15 days at a time, travel by kayak on the outer coast, and hike each day through thick forests to reach the sites. We’d wake up at 6 a.m. and it wouldn’t be until 11 a.m. that we reached the sites and actually started the day’s work of measuring trees.”

The field surveys revealed that yellow cedars inside of GLBA were relatively healthy and unstressed compared to trees outside the park, to the south. Results also showed reduced crowns and browned foliage in yellow cedar trees at sites outside the park, indicating early signs of the dieback progressing toward the park.

Additionally, modeling by study co-authors Paul Hennon, David D’Amore, and Dustin Wittwer at the USDA Forest Service suggested the dieback is expected to emerge inside GLBA in the future. As the region warms, reductions in snow cover, which helps insulate the tree’s shallow roots, leave the roots vulnerable to sudden springtime cold events.

Merging disciplines

In addition to collecting data about the trees themselves with a team of research assistants, Oakes conducted interviews with 45 local residents and land managers to understand their perceptions about climate change-induced yellow cedar dieback; whether or not they thought humans should intervene to protect the species in GLBA; and what forms those interventions should take.

One unexpected and interesting pattern that emerged from the interviews is that those participants who perceived protected areas as “separate” from nature commonly expressed strong opposition to intervention inside protected areas, like GLBA. In contrast, those who thought of humans as being “a part of” protected areas viewed intervention more favorably.

“Native Alaskans told me stories of going to yellow cedar trees to walk with their ancestors,” Oakes said. “There were other interview participants who said they’d go to a yellow cedar tree every day just to be in the presence of one.”

These people tended to support new kinds of interventions because they believed humans were inherently part of the system and they derived many intangible values, like spiritual or recreational values, from the trees. In contrast, those who perceived protected areas as “natural” and separate from humans were more likely to oppose new interventions in the protected areas.

Lambin said he was not surprised to see this pattern for individuals because people’s choices are informed by their values. “It was less expected for land managers who occupy an official role,” he added. “We often think about an organization and its missions, but forget that day-to-day decisions are made by people who carry their own value systems and perceptions of risks.”

The insights provided by combining ecological and social techniques could inform decisions about when, where, and how to adapt conservation practices in a changing climate, said study co-author Nicole Ardoin, an assistant professor at Stanford’s Graduate School of Education and a center fellow at the Woods Institute.

“Some initial steps in southeast Alaska might include improving tree monitoring in protected areas and increasing collaboration among the agencies that oversee managed and protected lands, as well as working with local community members to better understand how they value these species,” Ardoin said.

The team members said they believe their interdisciplinary approach is applicable to other climate-sensitive ecosystems and species, ranging from redwood forests in California to wild herbivore species in African savannas, and especially those that are currently surrounded by human activities.

“In a human-dominated planet, such studies will have to become the norm,” Lambin said. “Humans are part of these land systems that are rapidly transforming.”

This study was done in partnership with the U.S. Forest Service Pacific Northwest Research Station. It was funded with support from the George W. Wright Climate Change Fellowship; the Morrison Institute for Population and Resource Studies and the School of Earth, Energy & Environmental Sciences at Stanford University; the Wilderness Society Gloria Barron Fellowship; the National Forest Foundation; and U.S. Forest Service Pacific Northwest Research Station and Forest Health Protection.

For more Stanford experts on climate change and other topics, visit Stanford Experts.

Source : Stanford News


Achieving agricultural sustainability through seawater

Even though our planet is called “Earth,” over 70% of its surface is composed of water. Our continued existence depends on this vital resource but it is a staggering fact that only 1% of that water is directly accessible for human use. That is mainly because about 98% of the world’s available water is salty. This means that merely “2% of the Earth’s water is fresh water; but half of it is frozen in the form of glaciers and icebergs,” as Mark Tester, Professor of Bioscience at KAUST and Principal Investigator of the Salt Lab, explains.

The scarcity of fresh water supplies, surface water found in lakes and rivers as well as underground sources, poses a major challenge in the face of a growing world population set to plateau at 9 billion people by 2050. Fresh water is an essential part of our agricultural production infrastructure required to feed ourselves. Indeed, no less than “70% of the water that we use on the planet is used for agriculture. Moreover, 40% of our food is produced under irrigation,” as Prof. Tester outlines.

Global climate change is compounding the problem of water scarcity by altering rainfall patterns, reducing rainfall in previously well watered regions. The already limited supply of fresh water is also increasingly affected by salinity. “It would be wonderful if we could unlock at least a fraction of the rest of the vast amount of the world’s water resources,” as Tester further posits.

“So, in the context of needing to produce 70% more food by 2050, we have to both stop the reduction of yield already suffered from brackish irrigation water, and also unlock some of the other 99% of the water that we’re not able to use at the moment. Both of these things call out for our ability to increase the salinity-tolerance of plants.”

Making Our Current Plants Better

Prof. Mark Tester and his group, as well as other KAUST faculty members’ groups, are actively conducting experimental research in the University’s well-equipped greenhouse to find solutions to tackle our expanding food security challenges.

“We need to raise our ability to increase food supply,” said Tester. “We need innovation in plant science, modern plant breeding (e.g. quantitative genetics) and genetic modification.”

Prof. Tester’s group is primarily focused on studying how salt-tolerant plants are able to survive in harsh environments and then using that knowledge to make less salt-tolerant plants grow better in difficult conditions.

“We are trying to improve plant yields in sub-optimal conditions – where the soil is salty or when the water used to irrigate the plants is salty,” as Prof. Tester clarifies. His group essentially looks at the “naturally occurring variability in plants.”

How are some plants naturally able to better grow in salty water while others are less able to thrive in saline conditions? “I want to know what genes are in those tough plants that are missing from the less tough plants,” said Tester.

A Greenhouse Like No Other

These efforts, combining the observation of naturally occurring variations, the discovery of characterizing genes, and the measuring of the salt tolerance of plants require that KAUST plant scientists be able to grow plants in a controlled environment. These tasks are performed in the KAUST Center for Desert Agriculture (CDA)’s high quality 1600-square-meter greenhouse.

Prof. Mark Tester pointed out a unique feature of the greenhouse: a seawater tank. “We can water plants with seawater in this greenhouse. That’s pretty unusual,” he exclaimed. The filtered seawater greatly facilitates salinity experiments.

Another particular feature of the CDA greenhouse, unique to it’s location in Saudi Arabia, is that the water is actually cooled as it arrives from the desalination plant. This is to prevent the water warming the roots of plants in the soil – roots are used to be in the cooler soil, and are particularly sensitive to being warmed.

Different Approaches to Tackling Abiotic Stress

Given the fact that a quarter of the food that we produce under irrigation is already affected by salinity, a number that is rising rapidly, finding effective ways to use seawater to grow plants is of primary importance.

Prof. Tester recognizes the value of research towards this common sustainable agriculture goal also being conducted by fellow KAUST faculty members such as Prof. Heribert Hirt, who looks at solutions to increase plants’ tolerance to drought and heat, and Prof. Magdy Mahfouz, whose research interests focus on genome-engineering across plant species.

“Together we form a package of different approaches. All the approaches are good. There’s no one right approach. One might be better than another for particular circumstances, but they can all make a valuable contribution to improving crop growth in tough conditions,” said Prof. Tester.

How Plant Science Can Improve Food Security

Among the plants being cultivated and studied in the CDA greenhouse are rice plants. Demonstrating some of the crops that have grown in this controlled environment, Prof. Tester points out how “this one species of rice feeds half of the planet. It’s really important because it feeds the poor half of the planet – mainly in Asia and Africa.”

Taking into account the vital importance of rice crops to continue feeding the world’s growing population, it’s particularly significant that rice plants, as most crop plants, are salt-sensitive. They are indeed easily negatively affected by high salinity.

So Prof. Mark Tester and his team are studying the more salt-tolerant crops, such as barley and tomatoes, in order to better understand how they tolerate salinity, and then use that knowledge to improve other vital crops for our increasing food demands.

For instance, his team is growing a particular type of tomatoes, found on the Galapagos Islands, which are amazingly able to grow right at the edge of the sea and flourish in saline water. “We’re trying to discover the genes that are in these Galapagos tomatoes that allow the plants to grow in these crazy tough conditions,” said Tester.

“We want to use that knowledge to make commercial tomatoes even tougher,” he adds. By extension, “we can then turn our attention to rice and potentially improve its salt-tolerance.”

Source : KAUST News