April 5, 2018
By Liz N. Clift
In ecology, edge effect refers to changes in a population or community along the boundary of a habitat. A clear example of this is when an agricultural field meets a forest. Perhaps a less well-defined example is a fragmented habitat (such as those that occur because of selective logging or in areas impacted by human development (e.g. urban greenways or small areas of clear-cutting for ranching). Edge effect impacts of fragmented habitats may extend further into target habitat.
Think about it like this:
Assume, for the image above, that each example of a specific target habitat (green) has an area of 100m2 and that the edge effect for the target habitat is 10m. Habitat A has a relatively large area that has the least amount of impact due to edge effect (represented by the black outline). The interior of the habitat is undisturbed.
Habitat B, is discontinuous due to a meandering divided highway. This creates an edge effect (in black) that extends 10 meters on either side of the highway (represented by the dashed white lines) leaving the habitat fragmented and vulnerable to edge effects at each curve in the road as well as at the perimeter of the target habitat.
Habitat C is encroached upon (or is encroaching upon) a different habitat type (yellow)). Habitat C demonstrates the “peninsula” effect in varying degrees, which means that certain areas are fully impacted by the edge effect and other areas are less impacted. This habitat has greatest amount edge exposure.
Edges are sometimes thought to create areas of higher biodiversity, which can be true for soft edges, like ecotones. Ecotones (e.g. – the border between the High Plains and the Southern Rocky Mountains that makes up portions of Colorado’s Front Range or the banks of a pond) represent a gentler transition between two environments. Soft edges can also be designed, and in the ecological restoration field these are often referred to as “buffer zones.” In soft edges, the edge effect can become the transitional zone, which allows an intermixing of species that can move readily between both environments. For example, frogs begin their life in water and, as adults, split their time between land and water. A new hole in the canopy of a forest, because of selective logging or a tree falling because of natural causes, creates opportunities for other species to take hold.
Some birds of prey use the edge agricultural fields, parks, and roads as a fruitful hunting ground (not to mention the raptors that have adapted to urban living!). Not only is there no where for their prey to hide, they may also benefit from killed or injured animals that didn’t make it across unscathed.
Of course, ecology has no easy answers. The above examples can also lead to colonization of a habitat by an invasive or noxious species (e.g. – bull frogs along a pond edge, in areas where bull frogs are not native; English ivy in American forests). And in fact, edges can be detrimental for certain species.
The extent to which a species is impacted by edge effect is sometimes referred to its sensitivity to habitat edges. Sensitive species may be dependent on the state of interior conditions for their survival. In the example of a new hole in the forest canopy, shade-loving plants that survived due to the protection of that tree may fail to thrive (sub-lethal implications) or die back (which could provide the perfect place for an invasive species to take hold!). Trees along the (abrupt)edge of an agricultural field will experience more wind pressure, which could lead to die-back or stunted growth, even if they are established
In Braiding Sweetgrass, Robin Wall Kimmerer shares an example of how a fragmented habitat (which is divided by a highway) impacts a yellow-spotted salamander population:
“[Ambystoma maculata] come from under logs and across streams all pointed in the same direction: the [vernal] pool where they were born. Their route is circuitous because they don’t have the ability to climb over obstacles. They follow along the edges of any log or rock until it ends and they are free to go forward, on to the pond. The natal pond may be as much as half a mile away from their wintering spot, and yet they locate it unerringly…Though many other ponds and vernal pools lie along the route, they will not stop until they arrive at the birthplace…”
These migrating salamanders, Kimmerer goes on to describe, may face no greater danger than cars. Unlike frogs and other more ambulatory creatures that must cross a road during an annual migration, salamanders move slowly. They have no way to get out of the way of cars. This is where program’s like Burlington, Ontario’s (closing the road during salamander migration season) and amphibian passage ways (like this one in New Jersey) can help reduce edge effect—even if only temporarily.
Unfortunately, corridors are not always the straightforward answer—because these areas too, are impacted by edges. This should be planned for during the design and construction of such corridors, to whatever degree possible. Monitoring for invasive species or antagonist species (like predators) should also be part of corridor planning and management, since these species may also benefit from corridors connecting habitat areas.
Edge effects can differ by target habitat or population—and so it’s critical to clearly identify which specie(s) are of concern and their habitat requirements (including, potentially, abiotic conditions such as soil temperature or wind pressure). It may also be useful to identify corollary information such as:
Keeping edges in mind can help assess the impact of certain projects and help the public understand the benefits of a particular restoration project. Understanding edge effect can also guide management plans, which supports the long-term success of a restoration project or species conservation plan.
Featured image by: US Fish and Wildlife Service Mountain PrairieLeave a comment
March 22, 2018
By Liz Clift
Last month, we posted Part 1 of this blog with 10 words from our field that might improve your Scrabble game (or at the very least, help you out when you’re staring at your rack wondering what you do with those letters.
Now, we offer you Part 2. As with Part 1, points are based on the Hasbro website’s Scrabble dictionary, which assumes only the face value of tiles.
Apical (10 points) – in plants, refers to roots or shoot tips; it’s also a sound made with the tip of the tongue
Byssal (11 points) – relating to the super strong threads mollusks use to adhere to a surface
Also: byssus (but that seems like a waste of a lot of perfectly good S tiles)
Calyptra (15 points) – hood-shaped organ of flowers (according to Hasbro, anyway), but remember it as the gear that protects moss spores!
Gabbro (11 points) – a type of dark, igneous rock
Also: gabbroic (for 15 points)
Hypha (17 points) – the threadlike component of fungi
Octopod (12 points) – basically a very generic octopus; any order of an 8-armed mollusk
Operculum (15 points) – the little trap door on some snails (especially marine and aquatic snails)
Radula (7 points) – a rough, tongue-like organ on mollusks (you can remember this by thinking about the radiantly toothy smiles of snails)
Also: radulas, radulae
Seiche (11 points) – oscillation of an enclosed or partially enclosed body of water, often due to changes in atmospheric pressure
Thalweg (14 points) – a line defining the lowest points along the length of a riverbed or valley
Fun fact: I’ve actually managed to use thalweg in a game of Scrabble—and got that sweet 50 point bonus at the same time! Additional fun fact? The featured image is a hydra–which is another good word for using up some bizarre tiles you might have on your board!
Study up on these 10 words—we’ll have 10 more coming at you soon!
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March 9, 2018
By Liz Clift
It’s not always easy to know what’s happening in a landscape—or why it’s happening. This can be especially true if you’re not familiar with the native (or invasive) plants in your area, with natural local variations in topography, or with the presence/absence of certain animal species seasonally and generationally (among many other variables), although all of these factors offer clues.
However, the landscape frequently offers many clues as to its overall health—and potentially what has happened in its history, especially if you become familiar with plant species (which, unlike animals, can’t run away, swim away, or fly off when they hear you approaching).
One recent weekend, I was hiking through a park located in Washington state and noticed an abundance of blackberry (Rubus armeniacus) and English ivy (Hedera helix), both of which are listed as noxious weeds by the state of Washington. The rest of the park, by comparison, had very few noxious weeds present, and was instead dominated in the understory layer by sword fern (Polystichum munitum), snowberry (Symphoricarpos albus), thimbleberry (Rubus parvilorus), and assorted mosses, lichens, and liverworts.
This localized invasion of noxious species was a curious thing—and indicative of some sort of ecosystem disturbance. Later that evening, I began to research the history of that park. As it turns out, the park does have a history of ecological disturbance—namely a pipeline spill that resulted in a fire that tore down the creek channel for more than a mile (and at a fairly wide swath). Although this happened nearly two decades ago, the landscape is still recovering, and it shows. In fact, the sources I was reading specifically called out the invasion of blackberry as one of the lasting consequences of the fire.
Ecological disturbances, like fire, can make it easier for opportunistic species (such as blackberries, yellow star thistle [Centaurea solsitialis], or cheatgrass [Bromus tectorum]) to move into an area previously dominated by native plants. However, it’s important to note that the disturbance doesn’t have to be dramatic, such as a fire or scouring flood. These species will also take advantage of lands that have been grazed, worn down through unauthorized uses, or developed, where they are often able to outcompete native plants.
You can learn more about the noxious weeds in your area by looking at your state’s noxious weed control board, using the US Department of Agriculture noxious weed list for your state, or through your local department of agriculture. By becoming familiar with these species (especially those listed as Class B or Class C), you’ll find that you start to notice more of them in the landscapes and ecosystems around you. At times, this may even feel disappointing (I’ve definitely said, “that plant is pretty, it must be invasive”) as you begin to recognize how many plants you enjoy greeting are, in fact, not so healthy for your local ecosystem.
If that’s how you find yourself feeling about a particular plant, remember that all of these plants also have a place where they are native and that, in many cases, the reason that we have local problems with invasive plants is precisely because they’re beautiful—and so someone planted them ornamentally, only to have the plants go rogue. Instead, we should focus on the fact that plants in their native ecosystems aren’t typically invasive; their numbers are kept in check by a variety of environmental factors, including predators, disease, and rainfall.
Learning to read the landscape—as well as understand how to tell when things in a particular landscape seem generally (even if not specifically) off can yield clues to the health of the landscape, the history of the landscape, and perhaps even ecological reclamation or restoration work that has taken place.Leave a comment
March 1, 2018
by Liz Clift
I was in middle school when Titanic hit movie theaters. The RMS Titanic, which sank in April 1912, rests more than two miles below the surface of the water, off the coast of Newfoundland. And while the footage in the early scenes of the movie showing a submerged ship turned artificial reef are largely recreated, it provides a general idea of what the shipwreck reef actually looks like (note, the linked video is also clearly manipulated with ghostly figures to tug those heartstrings).
But as an aspiring marine biologist getting my feet wet (very literally) with freshwater ecology, I loved the idea of other animals reclaiming our wreckage—an idea which was gaining traction in restoration projects.
In the pond near my parents’ house, a dumped Christmas tree was an ideal spot to catch minnows (or sometimes young bluegill) and baby turtles. Although the Christmas tree in that pond was simply dumped—probably because a neighbor missed the cutoff for the city collecting Christmas trees—using people’s Christmas trees to create artificial reefs is something that fisheries program managers actually do. Beginning in 1992, at Lake Havasu in Western Arizona, a large habitat recovery program began to use discarded Christmas trees to create habitat* for young fish. Over the course of a decade, 875 acres of artificial reefs were created from cinderblocks, PVC pipe, concrete sewer pipe, and Christmas trees.
And the results were astounding. When the project started, divers monitoring these artificial reefs could “count all the fish at any spot on their fingers.” But, as time passed, these artificial reefs developed into sustaining habitat, a place for fish to spawn, breed, and grow to maturity. And sure enough, as the fish populations grew, so did the artificial reefs popularity as a local fishing destination.
Since Christmas trees take five or six years to decompose under water, the project is replenished with approximately 500 new trees every year—and more places are picking up the program. These Christmas tree reefs create fish nurseries, which are places for young fish to hide from larger fish and other predators. The algae, which grows on the decomposing trees, helps feed aquatic insects which feed a variety of fish and other aquatic animals, and can help oxygenate the water. (Too much algae can result in eutrophication, but that’s another blog post.)
Of course, Christmas trees are far from the only way to create freshwater reefs.
In Lake Michigan, there have been efforts to displace invasive species like alewives, round gobies, and the rusty crayfish through the creation of artificial reefs filled with cobble. This cobble is the appropriate size for native fishes, such as lake herring and lake trout (which have both maintained remnant populations for more than half a century). The folks leading this effort hope that by displacing the invasive populations of alewives (whose bodies contain an enzyme that makes their predators unable to reproduce) and developing a better understanding of how round goby and rusty crayfish interact with the reef through additional study, native fish populations will be able to rebound.
This, in itself, is an argument for making sure that restoration and conservation projects always include ecologists and biologists.
Similar projects are underway in other parts of the Great Lakes. And, those of us in the field of ecological restoration should take note. My guess is that if you’ve never lived in the Midwest, you probably don’t think about the Great Lakes all that often—but if you’re interested in artificial reefs, perhaps you should. Not only are these projects scaling up, they’re also providing plenty of research about what works and what doesn’t in these particular freshwater environments.
The Great Lakes offer a huge study area. Collectively, they have more than 95,000 square miles of surface water, enclosed in almost 8,000 miles of shoreline. And, they house an estimated 5,000 shipwrecks (which, we know in marine environments, can be the basis for impressive artificial reefs).
Many of the Great Lakes shipwrecks are accessible to Open Water-certified recreational divers and snorkelers (and even, in some cases, swimmers). The filtering capacities of invasive mollusks, like the zebra mussel and quagga have improved underwater visibility—which means that these wrecks are easier to see and photograph. Several just off the coast of Chicago, like the 200-foot long ferry, Straits of Mackinac and the shipwrecks near the Morgan Shoal, are being colonized by underwater life.
Although in the Great Lakes you’re not going to find the bright colors (or warm waters!) that would characterize a Caribbean shipwreck or decommissioned, near-shore oil platform in warm waters, that doesn’t mean these and other artificial reefs aren’t dive-worthy or of ecological and economic importance.
Regardless of whether an artificial reef occurs in a freshwater or marine environment, they add definition to the environment—textures, patterns, crevices, footholds, where before there was little or none. Life takes hold on these structures (often quite literally in the case of mollusks and some cnidarians), and life begets more life.
Providing more consideration to the potential benefits of artificial reefs is becoming increasingly important as incidents of coral bleaching, dredging, coastal run-off and proliferation of invasive species continues to occur.
At Great Ecology, we help design freshwater systems that encourage increased biodiversity and structural diversity, and have worked to improve the ecological function of a variety of freshwater ecosystems ranging from mountains streams, to lakes, to the mouths of rivers.
Through our partnership with Blue Latitudes, we also specialize in helping clients plan for end-of-life for marine structures, including oil and gas platforms. Check out our Platform Decommissioning services page to learn more about this work.
*Christmas trees have also been used to help create dunes—and while I like the story of Lake Havasu, the largest freshwater habitat recovery program of its time, similar programs were also starting up elsewhere.
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February 23, 2018
By Liz Clift
A few weeks ago, someone asked me to play a game of Scrabble, which is one of my favorite games. We settled down to play and I knew I had a bunch of unusual ecology words up my sleeve—if only the right letters would appear on my rack and on the board.
Ecology, like other specialized fields, has a lot of words you probably don’t hear often (or ever) if you’re not doing this work. The following ten words are just a sampling of some of words pertaining to ecology and ecological design that you might throw into your next game (and which are a length you could, feasibly, lay or connect onto the board without extraordinarily good fortune). Points are based on the Hasbro website’s Scrabble dictionary, which assumes only the face value of tiles.
Chitin (11 points) – the main component of insect shells
Chiton (11 points) – a type of ocean mollusk with eight plates, that outwardly resemble roly-polies (they aren’t related); a tunic worn in ancient Greece
Ligule (7 points) – a strap-shaped plant part
Limpet (10 points) – a type of mollusk
Petiole (9 points) – the stalk of a leaf
Protonema (13 points) – the cells that form in the earliest phase of life for mosses and liverworts
Senesce (9 points) – to deteriorate or wither
Also: senesces and senesced
Setae (5 points) – a coarse, stiff hair, like that on an insect
Spikelet (14 points) – a type of flower cluster
Stipule (9 points) – an appendage at the base of a leaf in certain plants
Study up on these 10 words—we’ll have 10 more coming at you soon!
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February 20, 2018
By Amber Jackson
The oil and gas industries, in the U.S. and abroad, have entered a new era of outer continental shelf activity. As the fixed structures of offshore drilling’s past slowly creep towards the end of their useful production lifetimes, the accelerating decommissioning market continues to evolve. From the Gulf of Mexico to areas off the coasts of Africa, the North Sea, and Malaysia, the decommissioning market is adapting to serve a range of depths and structures.
Traditionally, the decommissioning plan has defaulted to complete removal. In this process, the well is sealed, the drilling rig and all associated infrastructure are removed, and the seabed is ostensibly restored to its original condition. However, some of these platforms with their lattice-work superstructures of pilings, columns, beam, and pipes, have been quietly serving another purpose, below the surface, offering an artificial rocky substrate for a variety of economically and ecologically valuable fishes, including threatened species (i.e. rock fish in California and red snapper in the Gulf), invertebrates, and marine mammals.
Offshore platforms provide a refuge for vulnerable marine species, which is becoming especially relevant because nearshore habitats are more vulnerable to degradation through anthropogenic run-off, pollution, and overfishing.
Decommissioning these facilities into artificial reefs through the Rigs to Reefs (R2R) program presents an alternative to complete removal that may meet or surpass the level of environmental protection mandate by regulators. In fact, a recent study found that in California, the oil platforms “are among the most productive marine fish habitats globally.”
But not every platform is a suitable candidate for the R2R program. That’s when Great Ecology steps in. Using data collected both in the field and through scientific research, Great Ecology develops cost-effective and sustainable decommissioning strategies. We examine all options, from complete removal, to reef, to partial removal, to re-use to determine the strategy that would best serve to optimize your decommissioning project.
We understand that decommissioning planning is often an after-thought to the rush of oil exploration and the operation of offshore facilities. However, strategic decommissioning planning can result in major benefits: cost savings; streamlined permitting; regulatory compliance; environmental enhancement; and stakeholder engagement.
Discover a way to reduce costs by optimizing your decommissioning strategy and contact us today.
Amber Jackson is an ecologist at Great Ecology and co-founder of Blue Latitudes.Leave a comment
February 8, 2018
By Liz Clift
One of the gifts of TED talks is that you can learn a lot about a concept, idea, or experience in a fairly short amount of time. This may spark your interest enough to do further research on your own, provide fodder for a dinner conversation, help you reimagine the world, or reconsider your own preconceptions and biases about a particular topic.
Every so often, we post a list of TED talks we’ve especially enjoyed that are (at least roughly) related to our line of work, which we think you may enjoy as well. Here are five more we think you’ll enjoy.
In The Magic Ingredient that Brings Pixar Movies to Life (Danielle Feinberg, ~12 minutes), Feinberg discusses how the movie Finding Nemo creates a believable world that an audience can immerse themselves in (and understand some more abstract concepts, such as evoking sadness because of pollution in the Sydney Harbor or creating a more visual East Australian Current). This discussion of color and lighting can be applied to how we communicate difficult concepts to audiences, and serves as a good reminder for how we can get strangled by science when we remove it from art. Feinberg says, “It’s this interweaving of art and science that elevates the world to a place of wonder, a place with soul, a place we can believe in.”
What would a symphony of barometric pressure, wind, and temperature sound like? If you watch Art Made of Storms (Nathalie Miebach, ~4 minutes), you’ll have the opportunity to find out. As you know, if you’re a long-time reader of our blog, we’re always interested in unusual ways to convey (often dry) data and this is another great example—and she also creates 3-D models that show behavior relationships that might not be evidentif you’re just studying graphs.
Have we limited our idea of nature too much? Emma Marris, in Nature is Everywhere – We Just Need to Learn to See It (~16 minutes) argues that all landscapes are humanized to some degree, and that the results of our altering ecosystems (and the pure fact of animal extinctions) has changed landscapes. Marris proposes that if we define nature by where life is thriving, then we can see nature all around us, including in urban landscapes—which is important since 71% of people in the US live within a 10-minute walk of a city park. If we redefine nature to include that which we can touch, including the nature right around us, then we can inspire people to care.
Why Wildfires Have Gotten Worse – And What We Can Do About It (Paul Hessberg, ~14 minutes) examines the reasons megafires have become more common and explores the ways that we might escape the current trajectory we’re on in terms of fire management and patterns of development. Hessberg argues for “patchy” forests, meaning multi-age forests, with a combination of closed and open canopies as well as meadows, and for greater awareness of where we build.
An Economic Case for Saving the Planet (Naoko Ishii, ~14 minutes) In this talk, Ishii discusses how to avoid the tragedy of the commons, by accepting that our economies are no longer local and that the earth does not have unlimited capacity to self-repair. Ishii argues for green cities, changing our energy systems, changing our consumption patterns, and reimagining our food systems.
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February 1, 2018
By Liz Clift
We’ve watched the West burn. If you look at a map from last year—current as of December 28, 2017 at the time of this writing, the majority of the state of California appears freckled with fires of various sizes. Idaho and northern Nevada look much the same.
Property damage is what a lot of people think about first when they think of fire impacts—and not necessarily damage to the land itself, but the homes and businesses—and associated equipment, livestock, vehicles, and other tangible items on those properties. This damage is, at least, moderately easy to quantify, though devastating for the people impacted.
Often as a second thought, some people may consider the damages to the ecosystem and ecosystem services. For landowners, there may be a high intrinsic value on their land—but additionally, fires have implications for erosion, water quality, habitat, local temperature regulation, and more. These things can be harder to quantify—and to restore.
Perhaps one of the most prominent examples of impacts to ecosystem services over the past few weeks were the landslides in Santa Barbara County. These landslides were, in part, a result of the fired that destroyed many of the plants that help stabilize the ground and slow water during rain events. Additionally, the scorched ground made it more difficult for water to penetrate the surface of the soil (fire scorched soils often become hydrophobic), which meant that more of the rain ran off. So, when California’s winter hit the area post-fire, there was little stopping the water from gaining momentum.
The result, unfortunately, was rivers of mud.
In addition to causing earth movement, as landslides are often called, landslides have implications for water quality through increased erosion and disruptions to habitat for a variety of species, among other ecosystem impacts.
This adds another layer of complexity to assessing the damages from the fires—and highlights the importance of restoration work in areas impacted by fires. It’s not as simple as just spreading some seed or planting some saplings, especially in areas where fires burned extensively and sterilized the soil. Additional measures are needed to help restore the soil, decrease erosion, and improve habitat—particularly in areas that are known to provide a home to threatened or endangered species.
To restore these damaged landscapes, landowners must coordinate with a variety of stakeholders to complete the permitting efforts and get informed on fire ecology and the ecology of the region. Additional coordination includes: landscape design, the provision of the actual seeds and plants necessary for restoration to occur, construction of the restored landscape, and ongoing monitoring to ensure project success. And, of course, if a landowner’s insurance didn’t (fully) cover fire or land movement, funding the restoration could cause additional difficulties and delays.
You don’t need to go this alone. Great Ecology specializes in assessing damages to natural resources and impacts on a landscape scale, establishing a restoration plan, developing construction documentation, construction and post-construction monitoring, and providing litigation support.Leave a comment
January 25, 2018
by Liz Clift
“What we contemplate here is more than ecological restoration; it is the restoration of relationship between plants and people. Scientists have made a dent in understanding how to put ecosystems back together, but our experiments focus on soil pH and hydrology—matter, to the exclusion of spirit.” — Robin Wall Kimmerer, a scientist and writer
Pinus flexilis, the limber pine, has gained some level of notoriety in recent years—in part because these trees have the ability to live for a relatively long time and in part because they are competing with bristlecone pines (Pinus longaeva, Pinus aristate, and Pinus balfouriana) in movement upslope, in response to climate change. The oldest limber pine is estimated to be roughly 3,000 years old, and is located in Alberta, Canada (the oldest living bristlecone pine is estimated to be approximately 4,765 years old, for the record, and it lives in an undisclosed location in eastern California—in fact, it’s the oldest known living tree).
Many of us are, perhaps, particularly fascinated with long-lived trees now that we know that they might not always be around. Take, for instance, the news that’s been trickling in over the past few years about the decline of the redwoods in California or the logging of old-growth forests. These old trees provide habitat for a variety of animals and plants and can also tell us a lot about ourselves, if we take the time to study the rings and the forest around them.
At the Denver Botanic Gardens, there are several examples of limber pine I like to visit. They are small and look sturdy against the landscape, and I have to remind myself that although small, these trees are not all that young—some are older than I am. They’re set in an area that represents Colorado’s more extreme soil conditions: dry and rocky, and yet they’ve found purchase. There’s a lesson in that for all of us, and this is part of what makes the limber pine one of our more resilient trees in montane and subalpine ecosystems.
Limber pine is a keystone species in these montane and subalpine ecosystems. It provides food for a variety of animals, including bears, small mammals, and birds—and its needles are the sole food of a small ermine moth. Nutcrackers, a type of bird in the jay family, rely heavily on limber pine, particularly in certain areas—including Craters of the Moon National Park—where few other coniferous trees exist. This relationship is mutually beneficial, as nutcrackers create caches of seeds for the winter, but don’t return to all the caches, which allows these newly planted seeds the opportunity to take root.
Limber pine is also an effective pioneer in colonizing disturbed areas, and is able to stabilize soils in places where few other vegetative species thrive. Despite this, limber pine is rarely used in restoration projects because it is so slow growing—which makes achieving results within standard monitoring time frames a challenge, and as a result, the average landowner does not easily recognize the ecological value of using limber pine for restoration.
There’s something to be said for developing more patience with these, and other, slower-growing trees. It might not be us—or our children, or theirs—that see slow-growing trees reach maturity, but in this way we can be stewards of the environment for future generations. We can also learn, again, how to build a relationship with plants, to understand the role they play not only in the ecosystem, but in our lives.Leave a comment
January 18, 2018
By Kay Wiseman and Liz Clift
Fires in the west have become larger, more frequent, and more severe in recent decades. This upward trend is likely to continue, making it vital to understand the implications these massive fires have on our landscapes.
For nearly 100 years, fire management policy has established a best practice of suppression to control potential fires and sources of fire. However, suppression can lead to the disruption of natural fire regimes essential for fuel load reduction, seed germination, and soil nutrient cycling. Despite best efforts for prevention, fires continue to ignite and spread and with nearly a century worth of fuel accumulation, a wildfire can quickly turn into a devastating threat.
While there is room for debate as to what defines a “severe wildfire” in differing ecosystems, it is well documented that for the United States’ dry western landscapes fuel accumulation has been a major component for increased fire intensity. Heavy fuel loads can have multiple negative impacts:
There’s a balance though between removing fuel and allowing some of the vegetative fuel to stay because of the role it plays in a biotic community. Vegetative material that could easily become (excess) fuel provides beneficial soil stabilization and habitat areas. Fuels, such as senesced grasses, may allow soil to hold moisture more effectively or provide bedding or nesting materials for a variety of animals, as well as providing cover to small prey animals. Larger fuel, such as tree snags or “standing dead” trees provide nesting habitat for a variety of birds as well as a rich environment for a diversity of beneficial insects and fungi that provide decomposition—thus enriching the overall nutrients within the soil (and which may also be forage for a variety of animals, including some songbirds). Trees, even dead ones, may also provide soil stabilization for many years.
Additionally, if these fuels are fully cleared soil is exposed to sunlight and wind creating dry conditions more conducive to increased fire intensity or increased erosion. The presence of fuels is also essential for topsoil production and nutrient cycling—nutrients from vegetative fuels cycle back into the soil as they decompose—which is another reason that it should be considered undesirable to completely remove fuel sources from the landscape. Therefore, fuel management can be a delicate balance between leaving too little or accumulating too much. Other than the human safety aspect, why should we concern ourselves with fire intensity? Let’s dive more deeply into the points made in the bullets above.
Fires that burn underground—especially those burning peat—can release inordinate amounts of stored carbon. That’s because peat, which makes up only 3% of the world’s surface contains 25% of the world’s carbon soil. What does that mean? It means that there’s currently about as much carbon in the air as there is in all the peatlands in the world.
That’s not all. According to Guillermo Rein, an expert on smoldering fires, “Once ignited, these fires are particularly difficult to extinguish despite extensive rains, weather changes or firefighting attempts, and can persist for long periods of time (months, years), spreading deep (5 meters) and over extensive areas of forest subsurface” (as summarized by Andrew C. Revkin, for the New York Times). These fires occur in tropical, temperate, and boreal forests around the world—because peat exists on all seven continents, including places you might not expect if you don’t know much about the landscape.
Although it’s often easy for anyone who isn’t a soil scientist to see the soil as dirt, it is, in fact, alive with microorganisms and invertebrates which are integral to overall soil health. Additionally, a complex mycorrhizal (fungi!) system exists beneath the soil, which is integral to soil health (in particular helping different plants receive nutrients). Hot fires can kill this mycorrhizal system, which can take years or decades to restore. These intense fires can leave soils not only hydrophobic (which has implications for loss of soil function and may increase risk of erosion or downstream flooding and sedimentation), but effectively sterilizes the soil, leaving it a “moonscape.” This isn’t a reference to the moon that controls the tides—it refers to a post-fire devoid of all vegetation, potentially for years after the initial devastating fire. Moonscapes burned so hot below ground that seeds, soil microbes, and even the compounding properties of inorganic materials in the soil have been expunged.
Without protective vegetation and woody debris, the soil is left exposed to the elements. Exposure and water repellency increase the erosive potential of soil and the subsequent runoff after fires cause stream sedimentation and low water quality, because plants that may have normally acted as “filters” to rainwater or other precipitation were removed from the ecosystem as a result of the fire. In addition to increased repellency, the absence of plants in the landscape means that there is little to slow down precipitation—which can further decrease water percolation into the water table.
Crown fires—especially in the absence of intense ground fires—can provide new opportunities for younger trees and understory growth to flourish. However, the loss of the tree canopy can result in greater vulnerability for some canopy dwelling organisms, can increase damage to lower forest strata during precipitation events (canopies can effectively slow down rain, hail, for instance), and increase surface soil temperatures, due to the absence of the shading properties a full canopy provides during the hottest months of the year.
Restoring areas hit by severe wildfire is resource intensive and expensive but is also necessary to immediately stabilize soil and prevent future erosion, along with reviving ecosystem function. There are a variety of options for short term soil stabilization, and remediation, which can help limit some of the impacts of a fire on an ecosystem (and the human community that depends on that ecosystem as well). Long-term solutions must take into account the current soil quality, options for soil remediation (if appropriate), appropriate (native) plant communities, planting plans, and land management to support revegetation. Other abiotic factors, as well as the pre-fire history of the landscape, may also provide important clues about what restoration techniques will work best for the landscape.
But, these are reactions. We should also be having proactive conversations about how fire management plans can be effectively and appropriately incorporated into a variety of landscapes. These conversations—and the implementation of plans—will likely help fire managers effectively and safely reduce the fuel load that’s resulted from decades of fire suppression.
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