A sweeping series of plantation closures in Hawaii allowed highly flammable nonnative grasses to spread on idled lands, providing the fuel f
Excerpt from this story from the New York Times:
When Hawaii’s last sugar cane plantation shut down in Maui in 2016, it marked the end of an era when sugar reigned supreme in the archipelago’s economy. But the last harvest at the 36,000-acre plantation underscored another pivotal shift: the relentless spread of extremely flammable, nonnative grasses on idled lands where cash crops once flourished.
Varieties like guinea grass, molasses grass and buffel grass — which originated in Africa and were introduced to Hawaii as livestock forage — now occupy nearly a quarter of Hawaii’s landmass. Fast growing when it rains and drought resistant when lands are parched, such grasses are fueling wildfires across Hawaii, including the blaze that claimed at least 93 lives in Maui last week.
“These grasses are highly aggressive, grow very fast and are highly flammable,” said Melissa Chimera, whose grandmother lived on the Hawaiian Commercial & Sugar Company’s plantation in Maui after emigrating from the Philippines. “That’s a recipe for fires that are a lot larger and a lot more destructive,” added Ms. Chimera, who now coordinates the Pacific Fire Exchange, a Hawaii-based project sharing fire science among Pacific island governments.
Investigators are still scouring for clues as to what ignited the Maui blaze, which became the deadliest American wildfire in more than a century. But as the planet heats up, it is becoming apparent that even a tropical place such as Hawaii, known for its junglelike rainforests and verdant hills, is increasingly susceptible to wildfires.
The islands have long had arid stretches of lava fields and drier grasslands, with rainfall varying from one side of an island to the other. But in recent years, the state has also seen long-term declines in average annual rainfall, thinner cloud cover and drought induced by climbing temperatures. Seizing on data showing a spike this century in Hawaii’s destructive fire activity, specialists in mitigating wildfire hazards had already been issuing warnings for years about Maui’s growing vulnerability.
Giant Reed In The Tanque Verde Wash — Image by kenne
Giant reed is an invasive grass common to riparian areas, streams, and rivers throughout the Southwest. It thrives in moist soils (moderately saline or freshwater), sand dunes, and wetland areas.
Giant reed forms dense, monocultural stands and often crowds out native vegetation for soil moisture, nutrients, and space. When dry, it is highly…
Grasses that have encroached from other regions can make wildfires more frequent, according to a new study.
Excerpt from this New York Times story:
The fires that have ignited in California, leading to mass evacuations and seemingly otherworldly scenes, may have gotten their start from a surprising source.
Invasive grasses, or grasses that have encroached from other regions, can make wildfires more frequent, not just in California but nationwide, according to a study published Monday in the journal PNAS. The study looked at grasses like cane grass, which is native to Myanmar but is damaging ecosystems in Florida, and buffelgrass, which is helping to ignite fires in the Southwest and has origins outside North America.
“These grasses can act as kindling,” said Emily J. Fusco, a postdoctoral researcher at the University of Massachusetts, Amherst, and lead author of the study.
The species add to fire risk because they are growing in regions that once had far fewer grasses and because of their physical structure. Absent rainfall, the long, thin blades dry out quickly. This creates potential problems in places like California where most rainfall happens in the fall and winter, leaving the grasses to dry out in summer.
The grasses are more prone to burning than the native shrub land typically found in much of the West, including parts of California’s Ventura County, where the Maria Fire broke out late last week. After a fire, these grasses are able to grow back faster, leading to concern that they may replace less flammable shrubs.
“If we turn this place into a grassland, we’re going to be seeing fire every other year in individual locations,” said Dr. D’Antonio.
Invasion of the “Hoofed Locusts” and the Divine Bovine
Figure 1. John Muir an early 20th-century naturalist and advocate for wilderness preservation called the cow a “Hoofed Locust” (Hoch 2013)
Cows are firing off the tumblr page like cannon balls and into your head as we explore ecological imperialism, the importance of timing, and how invasive species can both royally degrade and restore ecosystems. This week’s post is about the ways we’ve made cows an epic force of ecological degradation, but also, about holistic efforts to turn them into a species-diversity builder and habitat rehabilitator.
POST BY: Alexandra Parvaz
Imagine if you will a cow freely roaming and grazing in a pasture, munching on forbes and grasses on a sunny sedating day. Imagine it in a vast wildflower-blooming field, and you see its marshmallow-soft skinned lips and jaw hypnotically circling in motion, shredding and chewing from side-to-side clumps of grass between its molars. Imagine as you try to stealthily approach it, your unforgiving feet step on some twigs that send out a crushing snap! startling our once blithe multi-stomach chambered beast. It immediately freezes its jaw and with vast deep black abyss-looking eyes stars at you… as you stare back at it. You’re both locked in each other’s gaze.
Figure 2. A Texas Longhorn- photo credit: Dave Welling
You barely breathe. It stands unshaken, until… finally! it picks up munching again…for another 5-7 hours… and on top of that for another 8-11 hours, re-chews its partly digested food, lovingly called.. the cud.
Figure 3. Diagram of a cow’s double digestion process
When not thinking about a cow’s fate to the slaughterhouse or to milking stations, it may seem like all that cows do is mind a seemingly eternal quest to eat, to lounge about, to regurgitate and re-chew cud and belch away. It's a fairly true state of being, and when well-fed, offered nice pastures and fellow cow company for the ‘cudding’, they seem like the most docile and big friendly chums.
Figure 4.
But! Are they also drivers of widespread ecosystem collapse and species extinction?
Figure 5.
If we carefully examine the roster of all the species believed to have existed over the past 500 years since colonists introduced the cow to the Americas, we’d find a lot missing. We’d also find a lot of new faces that kicked out many original species from the millions of acres of grazed land in a cow’s wake.
As our population increases and more diets become more meat-centered, the cattle industry has been building more and more cow lots to meet the growing demand for beef all over the world. In the U.S. alone, over 42% of total land area is rangeland for cows (Ditomaso 2000). In the process, though, the rise and reign of the cow is causing severe global environmental problems, including rampant deforestation, desertification (the transformation of once fertile lands into desert), soil erosion, water pollution from excessive manure loads, and staggering species-loss. Over 80% of deforestation in the Amazon is razed over for Cattle ranching. To create an ever starker visual, every 6 seconds, 1 acre of tropical rainforest is wiped out for pasturelands (Iacurci 2014).
Figure 6.
Addressing its global impact behooves us to look more deeply into the history of cattle. To keep it close to BIOTA’s site focus on California’s vernal pools, we’ll examine how cows have affected California’s coastal prairies and grasslands and paved the way for aggressive, self-sowing invasive grasses.
Figure 7.
If we go way back, the first grasslands in the Californian region took root over 3 million years ago (3MYA) in response to climate and millions of years of land movement. However, during the geologic period called the Pleistocene Epoch, (2.58 MY-12,000 YA) gigantic tromping mammals called Megafauna started to migrate into the Americas after scaling across a huge land mass called the Bering Land strait that connects North America to Asia (this land bridge is currently under water). Their presence helped wage dramatic changes to the structure of the grasslands (Immel-Jeffery 2013).
Figure 8. A fancy rendering of Mammoths grazing in the background, and mega-carnivores hanging out at a watering hole.
Herbivores (mammals with a plant-based diet) like Mammoths, Mastodons, ancient Elk, gigantic Sloths, Oxen, Three-toed Horses and Zebras helped trigger the co-evolution of a diversity of annual and perennial plants that developed in response to their eating behaviors, either through Grazing or Browsing. Grazers, like modern-day Bison, Elk, Cows and Sheep, primarily feed on grasses, have specialized broad muzzles and four chambered stomachs to break down the tough tissues. Browsers, contrarily, feed on leaves, and small buds, and have narrow muzzles like Deer, and Horses.
How they walked and if they were keen to trample a lot also affected the evolution of new vegetation. In the North coast of California, Mammoths were a major force that in all their stomping about and hearty grazing wiped out the existing forests, changing them, through their collective eating habits into grasslands. An explosion in wildlife diversity occurred over the millennia, with a staggering variety of herbivores, carnivores and scavengers including Ice Age bison, pre-historic lions, the American Cheetah, and mega-sized condors called Merriam’s Teratornis.
By 11,000YA, humans, following the trail of these wooly beasts, finally made their debut into the Americas and set off another massive change to the ecosystem; the Megafauna Massacre. Nearly all of the iconic big creatures vanished and while climate change, exploding comets, and the spread of diseases played a role in their sweeping disappearance, the majority of scientists say, hands-down, humans hunted them to extinction within a mere 1,000 years (Immel-Jeffrey 2013).
Figure 9. The plush descendants of the wooly mammoths
The remaining creatures like Elk, Pronghorn, and Bison and a slew of others continued to thrive alongside indigenous peoples who helped further shape and maintain the grasslands for thousands of years, using the plants for food and various materials. One maintenance method included the frequent use of fire that helped increase the quality and variety of grasslands plants, all the while suppressing certain types of trees, and shrubs that would’ve otherwise have had an opportunity to emerge.
With the invasion of the Spaniards in the late 18th century and subsequent colonization, though, they radically changed the composition of the grasslands as they imposed totally different land management practices, suppressed fire regimens, and introduced their domesticated creatures. In come THE COW.
Figure 10. Cud-lipped and a saliva-d cow jowl
Following the violent removal of vast numbers of indigenous people and the take over of the coastal prairies, colonists set free their cattle, sheep and horses to feast on the incredibly nutrient rich and productive grasses, unleashing a myriad of ecosystem breakdowns.
Species Loss and Invasion:
Since then, the cultivation of farms introduced new crops of plants, both intentionally and unintentionally. Loads of seeds of other foreign plants like Yellow Star-thistle or Cheatgrass were accidentally carried over to the region from contaminated alfalfa seed bags or that tagged along on their livestock’s fur or within their digestive systems.
Figure 11. Yellow Start thistle in bloom
It has an advantage over native plants because it matures earlier in the season. Its roots rapidly grow as far as 3 feet down into the soil stealing water and nutrients that the native plants need to survive the hot summer. Yellow starthistle degrades wildlife habitat and chokes out desirable species with ruthless indifference. ‘Chewing disease’ results when horses eat yellow starthistle. This disease affects their nervous system and is usually fatal.
As the new grazers spread across the region, the livestock themselves helped sow these seeds from their manure and many of these seed bombs took off like wildfire. They aggressively spread throughout vast tracts of land, changing the vegetational and animal species makeup of the grasslands as their main food sources disappeared.
The combination of heavy overgrazing by livestock and introduction of non-native plants displaced the hearty species-rich, mostly native perennial bunchgrasses to, in many cases, lower-quality, low species-count annuals that ironically livestock don't often favor and may even be toxic.
Figure 12. Desertification in action
Throughout California and the western US, native grasses like Needle-and-Thread grass, Squirrel Tail, Great Basin Wild Rye, Bluebunch wheatgrass, Sandberg Bluegrass and Idaho fescue were overgrazed and out-competed by winter annual grasses and shrubs. This type of behavior where a plant successfully takes over a resource, and establishes itself without human assistance to the detriment of other neighboring native plants is called an Invasive Plant. Some like Spotted knapweed or Dyer’s woad are known to develop deep taproots that suck out all the available water in the soil, starving out other neighboring native plants. State and federal governments have called these plants Noxious that pose a severe threat to livestock, agriculture as well as native species and have placed a bounty to eradicate them.
Fire –Suppression:
Adding tinder to the flames of destabilizing change was the absence of a frequent fire regimen that native grasses co-evolved with over millenia. This has resulted in many cases the invasion of more fire-prone plants like Cheatgrass.
Figure 13. Cheatgrass
With livestock eating too much of grass to nearly the bare ground, cheatgrass has thrived on such heavily disturbed soils, unlike native plants. As a result, they have spread and triggered wildly severe fire sprees that have harmed native forbes and grasses that have not enough time to recover. Life a vicious cycle, the cheatgrass feeds on this type of system, dropping its seeds before a fire, and quickly sprouting afterward, only to make dense stands that are perfect tinder for another ignition. The plant is all over California and has spread all over the US, and many other continents.
Among the most famous and iconic large mammals driven to extinction by cattle includes the once notorious California Grizzly Bear where predator-control policies allowed every last bear up until 1924 to be hunted down. It’s legacy now rests on the California flag.
Figure 14.
According to the U.S. Forest Service, the lack of a more ecologically healthy livestock management system has threatened or endangered upwards of 175 species that are still hanging in there.
In the face of so much foot-shooting for the sake of hamburgers and milk, however, some very creative interventions are being practiced to both protect native species and habitats while making cattle raising more sustainable. One such measure is called Prescribed Grazing or Conservation Grazing. These methods seek to use cattle in ways that both help manage the spread of invasives while encouraging the re-establishment of native grasses and forbes. Scientists in collaboration with ranchers and farmers are working together to create a win-win by helping restore habitat for other native plants and animals while also, enhancing the quality and diversity of plants for healthier livestock. By appropriately timing cows’ grazing periods so they avoid eating too many of the native grasses, or with respect to invasives-control, graze on them when the invasives are at a stage of development when most vulnerable, researchers have achieved amazing results. In one study of 72 vernal pools in Eastern Sacremento California, researchers discovered that pools where 5 years worth of moderate grazing was held helped bring in more native species and effectively suppress invasives than sites where either no grazing was held at all.
Through collaboration, and wholistic thinking with cows, we might just bring milk a more fruitful future.
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