Article: The Wildest Idea on Earth

Imagine living in close proximity to numerous national parks and being “enveloped by connected [wildlife] corridors” that lead to these national parks – or as Edward O. Wilson envisions them, “national biodiversity parks, a new kind of park that won’t let species vanish.” Wilson – a renowned biologist, entomologist, conservationist and Pulitzer Prize winning author – has this vision and believes that it can be accomplished within the next 50 years. Not only can it be accomplished, but it must be in order to thwart the ongoing sixth mass extinction event. To be precise, half the planet must be set aside, restored to its natural state, and protected in perpetuity. A series of large parks connected by continuous corridors – or “Long Landscapes” – is the way Wilson and other conservationists insist this must be done. Tony Hiss explores the “Half Earth” concept in a feature article in the current issue of Smithsonian entitled, The Wildest Idea on Earth (the online version is entitled, Can the World Really Set Aside Half of the Planet for Wildlife?).

Hiss, accompanied by Wilson, visits three locations in North America where this vision is playing out. Their first stop is Nokuse Plantation in the Florida panhandle, where businessman, M.C. Davis, has purchased tens of thousands of acres with the intention of restoring them to native longleaf pine forests, a plant community that has been reduced by 97% due to human activity. Intact longleaf pine forests are incredibly diverse – as many as 60 different species of living things can be found in one square yard – so protecting and restoring them is an ecological imperative.

Longleaf Pine, Pinus palustris (photo credit: wikimedia commons)

Longleaf Pine – Pinus palustris (photo credit: wikimedia commons)

Later, Davis flies Hiss and Wilson to New England in his private jet. There Hiss discovers a seemingly accidental series of connected natural and restored landscapes nearly 200 miles in length. This corridor, and the land that surrounds it, highlights the need for private land owners to be on board with the Half Earth vision, setting aside their land for conservation in exchange for tax breaks and other incentives.

The importance of private land owners cooperating with this vision comes into play again when Hiss visits the Flying D Ranch near Bozeman, Montana. This 113,613 acre ranch (just a small fraction of the land owned by Ted Turner) is a private ranch that “promote[s] ecological integrity” – it is a wildlife refuge that also turns a profit. Fortunately, the “D” sits within larger wildlife corridor projects – Yellowstone to Yukon and Western Wildway Network highlighting Wilson’s vision of current sanctuaries being incorporated into larger networks of protected lands.

Hiss notes that as these three projects grow and connect to “the great, unbroken forests across all of northern Canada,” North America will become enclosed in “Long Landscapes” with “additional and more inland routes to be added later.” The sooner these corridors and parks are developed the better, because as global climate changes, species will need to move north, south, east, or west as their ecological and biological needs dictate.

It seems a lofty goal. Humans, after all, have spread themselves across the entire planet, modifying every environment as they go – oftentimes to an irreparable extreme. But knowing this, and recognizing that we are only just beginning to feel the effects of climate change, drastic measures to preserve what is left of this planet’s biological diversity become imperative. Hiss’s article is encouraging in this regard. Yes, the places he visited were confined to North America. A more accurate picture could be constructed by incorporating greater international diversity. However, most promising is that the people he talked to were not political figures. Most of them weren’t even professional scientists. They were businessmen, working people, land owners, citizen conservationists. Wealthy, yes. But people who, at some point in their life journeys, saw a need and wanted to help. The story of M.C. Davis illustrates this best of all. If the information is put out there in a manner that people can relate to, they will latch on to it and offer assistance. For all whose goal is to protect half of the earth (or even just some small portion of it) for the sake of non-human life, this article should give some hope.

Tree growing along a creek bed at The Nature Institute, a privately owned nature preserve in Godfrey, Illinois

Tree growing along a creek bed at The Nature Institute, a privately owned nature preserve in Godfrey, Illinois

Kudzu Ate the South…Now Looks North

In 1876, an Asian vine was introduced to the people of the United States at a centennial celebration in Philadelphia, Pennsylvania. It was a fairly benign looking vine, with its leaves of three and its cluster of sweet pea like flowers, but its exotic appeal must have been quite enticing, because it took off…and not just in popularity.

The plant that caught the eye of these early Americans was called kudzu (or kuzu in Japanese). It is a plant in the genus Pueraria in the family Fabaceae (the pea family). The plants first introduced to the U.S. were likely to have consisted of more than a single species such as P. montana, P. lobata, P. edulis, and others, or were hybrids of these species. They were initially lauded for their ornamental value but soon after were recognized for their potential as animal feed. By the 1930’s, when soil erosion had become a major issue, kudzu was deployed by the U.S. government to combat it. At least 85 million government-funded kudzu seedlings later, and the southeastern portion of the United States had secured a future dominated by this relentless and unforgiving vine.

Innocent and harmless is how kudzu must have first appeared, especially to those looking for a fast growing, large-leaved, vining plant to provide quick shade for porches, offering relief from the sun during those sweltering southern summers. Little did they know, however, if left unchecked, that prized vine could engulf homes and outbuildings, cover and pull down trees and utility poles, and choke out crops and pastures in the matter of a single growing season.

(photo credit: eol.org)

(photo credit: eol.org)

Kudzu was added to the Federal Noxious Weed List in 1997, long after it had established itself throughout the southeastern U.S. It now covers more than 3 million hectares, spreading at a pace of about 50,000 hectares (120,000 acres) per year. It is said that a kudzu vine can grow up to a foot in a single day or about 60 feet in a growing season. It is a twining vine, wrapping itself around any upright structure it can access and relying on that support in order to advance upwards. This gives it the advantage of using more resources for growth and expansion of both roots and shoots rather than on the resource demanding task of producing woody stems. Like other members of the pea family, it gets much of its nitrogen from the atmosphere through a process called nitrogen fixation. Because of this, kudzu can thrive in nutrient poor soils. Kudzu is also drought-tolerant, has leaves that follow the sun throughout the day in order to maximize photosynthesis, reproduces clonally by layering (stems in contact with the ground grow roots and detach from the parent plant), and (in North America) is free from the pests and diseases commonly associated with it in its native habitat. For these reasons and others, kudzu has become one of the most notorious, pervasive, and ecologically harmful weeds in the U.S., costing hundreds of millions of dollars in damages every year.

A close-up of kudzu flowers (photo credit: wikimedia commons)

A close-up of kudzu flowers (photo credit: wikimedia commons)

kudzu foliage and flowers

Foliage and flowers of kudzu (photo credit: wikimedia commons)

One glance at what kudzu has done in the southeastern states, and it is obvious that it is some kind of superweed. I saw firsthand just how overwhelming it can be as I drove through Mississippi several years ago. I didn’t even have to stop the car to investigate. It was easily apparent that it was the dominant species, enveloping every tree for miles alongside the highway. Currently, kudzu can be found in every county in Georgia, Alabama, and Mississippi. But kudzu has a limitation; it doesn’t care much for freezing temperatures. Even though it has been present in parts of northern states – like Ohio, New Jersey, and Delaware – for a while now, it has generally been limited to milder locations, and it certainly doesn’t thrive in the same way that it does in the subtropical climates of the southern states. But that is changing, because the climate is changing.

Average global temperatures increased by about 1.53° F between 1880 and 2012, and this gradual increase is expected to continue for the foreseeable future. Biologists and ecologists are monitoring changes in climate closely in order to observe and predict changes in the biology and ecology of our planet. Invasive species are high on the list of concerns, as climate is often a major limitation to their spread. Now that kudzu has been found in Marblehead, Massachusetts and Ontario, Canada, the fear of kudzu climbing north is becoming a reality.

Kudzu is incredibly difficult to control. It does not respond to many herbicides, and the herbicides that do affect it must be applied repeatedly over a long time period. It is an excellent forage plant, so utilizing grazing animals to keep it in check can be effective. Those who have succumbed to kudzu, acknowledging that it is here to stay, have found uses for it, including making baskets, paper, biofuel, and various food items. A compound extracted from the kudzu root is also being studied as a possible treatment for alcoholism. Kudzu has long been valued for its culinary and medicinal uses in Asia, so it is no surprise that uses would be found for it in North America. However, North Americans who embrace kudzu are taking a defeatist approach. That is, “if we can’t get rid of it, we may as well find a use for it.” This, however, should not negate nor distract from the damage it has caused and continues to cause local ecosystems and the ecological threat that it poses to areas where it is just now being introduced or may soon be introduced due to our warming climate.

Millions of dollars are spent every year to address the effects kudzu has on utility poles (phot credi: eol.org)

Millions of dollars are spent every year to remove kudzu from utility poles and replace poles pulled down by kudzu (photo credit: eol.org)

References:

Encyclopedia of Life: Pueraria Montana

Wikipedia: Kudzu in the United States

Max Shores: The Amazing Story of Kudzu

U.S. Fish and Wildlife Service: Conservation in a Changing Climate

NASA Earth Observatory: How Much More Will the Earth Warm?

Bloomberg: Kudzu That Ate U.S. South Heads North as Climate Changes

Horticulture Students Wanted

“Horticulture is under siege.” At least that’s the claim made in a letter and action plan penned by the top administrators of six prominent horticulture institutions based in North America. In their letter addressed to “Colleague[s] in Horticulture,” they claim that among the general public there is a “lack of horticulture awareness and poor perception of horticulture careers”. This has lead to low enrollment in high school and college horticulture programs and a dearth of qualified, young horticulturists entering the work force. Because the youth of today “appear to have little or no awareness of the importance and value of horticulture,” they are not choosing to pursue “interesting, challenging, and impactful careers” in the field.

In order to address this issue, this team of horticulture professionals has developed a plan “to increase public awareness of the positive attributes of horticulture.” Plants are essential for life on earth; humans could not exist here without them. It is the field of horticulture that supplies humanity with much of the food that it consumes, including fruits, vegetables, nuts, and herbs. Horticulture also fills our landscapes with plants that provide the backdrop to our daily lives, transforming otherwise drab and harsh urban areas into lush green spaces. And speaking of “green,” horticulture is helping us save our planet. Through teaming up with engineers and other professionals, horticulturists are helping to develop solutions to issues like climate change, water quality, storm water runoff, energy production, and biodiversity loss. Innovative and emerging strategies such as green roofs, wildlife gardens, carbon sequestration, biofuels, and sustainable agriculture require horticulture expertise in order to succeed.

These are just some of the benefits of horticulture that the authors of this plan hope to share with the general public in an effort to change public perception and attract young recruits. If they don’t succeed, the consequences may be dire – or at least that’s how they make it sound. An article on philly.com regarding the recent letter put it this way: “if something isn’t done soon…horticulture could become a lost art and a forgotten science.”

Yeah, it’s a bit dramatic sounding. It’s hard for me to believe that the situation is really that desperate. However, what I will say is that a career in horticulture is not for everyone. It certainly isn’t for anyone who dreams of being rich and/or famous one day. That’s probably not going to happen. People who choose a career in this field do so because they have a passion for plants, a love of beautiful, inviting landscapes, and perhaps a proclivity for fresh, homegrown fruits and vegetables. A career in horticulture is not glamorous by any means, but it is highly rewarding – at least from my perspective. So sure, youngsters should consider it…but they should also consider themselves warned.

And now it’s time for show and tell. I graduated with a degree in horticulture at a four year university in the intermountain northwest. After that, I ventured off to the Midwest to pursue a graduate degree researching green roof technology. Perhaps the following pictorial of some of my adventures will inspire a few of you young folks to consider a similar path. Either that or there is always that liberal arts degree you’ve been dreaming of…

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As an undergraduate, I helped manage a student-run organic farm

community garden plot

I had a community garden plot overlooking the rolling hills of the Palouse

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I took a jet boat trip up the Snake River to help prune an abandoned apple orchard

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Then I went to Illinois to study green roof technology as a graduate student

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I presented my research findings at a big conference in Philadelphia

And so can you…or something like it. Comment below if you would like to put in your plug (or caveat) for pursuing a career in horticulture. The world needs you.

In the News: Declining Insect Populations

Last week the New York Times published an article about declining populations of insects in the United States, specifically monarch butterflies and wild bees. Monarch butterflies migrate south to Mexico each fall, typically arriving by the millions on the first of November. This year was tragically different, because the monarchs did not arrive on the first, and when they finally began trickling in a week late, there were significantly less of them. In his article, The Year the Monarch Didn’t Appear, Jim Robbins discusses why this and similar scenarios are becoming commonplace.

Increased pesticide use and global climate change are certainly contributing factors in the decline of insect populations; however, Robbins suggests that the loss of native habit is the major culprit. For example: monarch butterflies rely on milkweed (Asclepias spp.); in fact, their larvae feed exclusively on it. No milkweed = no new monarch butterflies. Urban sprawl, farmland expansion, Roundup Ready crops, and herbicide use along roadways all result in declining milkweed populations, as well as declines in the populations of other beneficial native plants.

And that’s not all. “Around the world people have replaced diverse natural habitat with the biological deserts that are roads, parking lots and bluegrass lawns, ” says Robbins, meanwhile landscape plants are selected for their ornamental appeal, “for their showy colors or shapes, not their ecological role.” In support of his argument, Robbins cites studies which found that native oak and willow species in the mid-Atlantic states are hosts to 537 and 456 species of caterpillars, respectively. On the other hand, non-native, ornamental ginkgoes host three.

Insects provide numerous ecosystem services. They help break down waste products, they are pollinators of countless species of plants (including many of our crops), and they are food sources for larger animals (including birds, reptiles, and amphibians)…and this is just the short list. As John Muir said, “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” Thus, the decline of native insect populations is a concern that should not be taken lightly.

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Asclepias tuberosa – butterfly milkweed

If you haven’t already, please consider including some native plants in your yard. If you don’t have a yard, suggest the idea of landscaping with native plants to your friends. To learn more about monarch butterflies and their plight (including information on how to grow milkweed), visit www.monarchwatch.org.

Baobab Trees Facing Extinction

Declining populations of baobab trees have been a concern for more than a decade now. That concern has been amplified with the release of a recent study that shows that two baobab tree species endemic to Madagascar risk losing the majority of their available habitat due to climate change and human development in the coming decades.

Baobab trees are spectacular sights. Unique in appearance, they can grow up to about 100 feet tall with trunk diameters as wide as 36 feet and can live for hundreds (possibly thousands) of years. As the trees age, they develop hollow trunks used for storing water (as much as 26,000 gallons!) to help them survive long periods of drought. The fruits of baobab trees are coconut-sized and edible and are said to taste like sherbet. The leaves of at least one species are eaten as a vegetable, and the seeds of some species are used to make vegetable oil. Various other products, including fibers, dyes, and fuel are also derived from baobab trees.

There are nine species of baobab trees (Adansonia spp.). Eight are native to Africa and one is native to Australia. Two of the African species are also found on the Arabian Peninsula, and six of the African species are found only on Madagascar. Three of the Madagascan species (A. grandidieri, A. perrieri, and A. suarezensis) are listed as endangered on the IUCN Red List. Currently, A. perrieri has the lowest population of the three species, with only 99 observed trees. It is estimated that by 2080, its range will be reduced to 30% of what it currently is, further threatening its survival. A. suarezensis has a considerably larger population (15,000 trees) but a much smaller distribution area (1,200 square kilometers). By 2050, this area is estimated to be reduced to only 17 square kilometers, practically guaranteeing its eventual extinction. On the bright side, A. grandidieri has a population of about one million trees and an extensive range that should remain largely undisturbed in the coming decades.

An interesting component to this story is how giant tortoises fit in. The fruits and seeds of baobab trees are relatively large, and so their dispersal is best carried out by animals. Seeds that fall too close to the parent trees have little chance of survival since they will be shaded out and will have to compete with large, adjacent trees. Animals that eat the fruits of the baobab trees help to disperse the seeds by defecating them in areas away from large trees where the seedlings will have a greater chance of survival. Two species of giant tortoises that were once native to Madagascar but have now been extinct for hundreds of years were likely primary dispersers of baobab tree seeds. A recent study used a species of giant tortoise not native to Madagascar (the Aldabra giant tortoise) to test this hypothesis. The tortoise readily consume the fruit of the baobab tree. The seeds remain in the tortoise’s digestive system for up to 23 days, giving the tortoise plenty of time to move to an area suitable for seed germination. Given these findings, biologists are currently working to introduce Aldabra giant tortoises to Madagascar to help save the baobab trees.

Climate change, loss of habitat due to human development, and loss of seed dispersers due to extinction threaten the survival of some baobab tree species, but by recognizing this threat, biologists can work towards preventing their eventual extinction. As we gain a better understanding and appreciation for the need for biodiversity on our planet, we will resolve to take greater steps to protect it.

To learn more about baobab trees facing extinction and giant tortoises as seed dispersers, visit the Scientific American blog, Extinction Countdown, here and here.

baobab tree

Adansonia grandidieri

photo credit: wikimedia commons

Autumn Leaves

It’s October, so fall is in full force in the northern hemisphere. Days are shorter and temperatures are cooler, but one sure sign that fall is here is that the leaves on deciduous trees are changing colors. Every autumn, leaves that were once a familiar green turn brilliantly red, fiery orange, or vibrantly yellow. And then they fall to the ground leaving trees exposed – just trunks and branches  – skeletons of what they once were during warmer and brighter days.

But why?

Surprisingly enough, the colors seen in autumn are largely present in the leaves throughout their lives, but we don’t see them. We only see green. This is because chloroplasts (cell organelles responsible for carrying out photosynthesis) contain chlorophyll, one of three main pigments found in the cells of leaves throughout the growing season. Chlorophyll absorbs red and blue light and reflects green light. Because chloroplasts are so abundant in the cells of leaves, leaves look green.

But carotenoids are hanging around, too. The second of the three main pigments, carotenoids protect chlorophyll from oxidation and aid in photosynthesis. They reflect blue-green and blue light and appear yellow, however their population is considerably smaller compared to chlorophyll, so their yellow color is masked.

When day length decreases, the level of chlorophyll in plant cells diminishes. As a result, the yellow color of the carotenoids begins to show. Also, a layer of cells called the abscission layer forms between branches and petioles (i.e. leaf stems). This abscission layer is what eventually causes branches to drop their leaves. As the chlorophyll begins to die off and the abscission layer forms, anthocyanins (the third of the three main pigments found in plant cells) are synthesized. Anthocyanins absorb blue, blue-green, and green light and appear red.

With chlorophyll virtually absent (and photosynthesis brought to a halt) carotenoids and anthocyanins become the major pigments found in leaves, giving them the autumn colors we are accustomed to seeing. But here is where it gets tricky…

Fall leaf color is largely dependent on various environmental conditions, including temperature, amount of sunlight, and soil moisture. If autumn is warm and wet, chlorophyll may be slow to die, and anthocyanins may be slow to form. Chlorophyll drops off more readily when it is cool and dry, and anthocyanins synthesize more readily when days are sunny. Dry, sunny days followed by cool, dry nights are said to offer the most vibrant fall colors. Additionally, global climate change is now playing a role, so fall colors may start to appear earlier or later or last longer or shorter depending on the region.

Do you have a favorite place to view fall foliage? Add your comments below.

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Cornus sericia – red-osier dogwood

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Ribes aureum – golden current

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Quercus palustris – pin oak

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Fraxinus sp. – ash

ailanthus

Rhus sp. – sumac

A Plant Community’s Response to Climate Change

The threat of ensuing climate change has led many to consider what the future might look like for life on earth. Plant life will undoubtedly be affected, and numerous observations have already been made indicating that plants and plant communities are responding to changing climates.

A recent study, published in Ecology and Evolution, documented changes in the lower elevation boundaries and elevation ranges of common plants found on the Santa Catalina Mountains (near Tucson, Arizona). A study of this caliber is rare because there is relatively little data available to observe such changes over a long period of time. The scientists that carried out this study were able to use survey data collected by Robert Whittaker (the father of modern plant ecology) and William Niering in 1963. Whittaker and Niering conducted an extensive survey of plants along the Catalina Highway, which still exists today and runs along the southern slopes of the Santa Catalinas. Following similar data collection methods, researchers from the University of Arizona surveyed plants along the Catalina Highway nearly 50 years after the original survey. What they found confirmed predictions: montane plants in the southwest are responding to a warmer and drier climate by shifting their lower elevation limits upward.

The average annual air temperature in this region has increased an average of 0.25 degrees Celsius per decade since 1949. Also, rainfall has decreased significantly since Whittaker and Niering’s original plant survey. Twenty seven of the most common plant species were selected from the new survey and compared to the original survey data. Fifteen of the twenty seven species (56%) have significantly shifted their lower elevation boundaries, moving further up the slopes of the mountains to escape higher temperatures and reduced rainfall. Some of the plant species have also shifted their upper elevation boundaries, with four of them moving further upslope and eight of them moving further downslope.

The authors of this study state that “even a casual observer could recognize changes in plant elevation boundaries.” Alligator juniper, bracken fern, beargrass, and sotol are examples of plants in the Catalinas that have noticeably migrated upslope and are no longer found at lower elevations where they were once common. Alligator Juniper (Juniperus deppeana), for one, was once documented growing at least as low as 3500 feet, but now does not occur until after the 5000 feet mark.

This rare opportunity to compare current plant survey data with old data paints a stark picture regarding the effects of climate change. As plants and animals are forced upslope to escape warmer and drier climates, they may eventually find themselves with nowhere to go and ultimately end up extinct, reducing overall biodiversity on the planet. The authors of this study conclude their findings with this statement: “The shifts in plant ranges we observed in the Santa Catalina Mountains indicate that the area occupied by montane woodland and conifer forests in the Desert Southwest is likely to decrease even more with predicted increases in temperature, and that regional plant community composition has and will continue to change with further warming as plant species respond individualistically to changing climates.”

Read more about this study at the University of Arizona news site.

alligator juniper_juniperus deppeana

Alligator Juniper (Juniperus deppeana)

photo credit: wikimedia commons