August 23, 2018
By Amber Jackson
If someone asks you to describe spring or summer, you might talk about new life, with pops of color flowering in open spaces and on trees, and a seemingly endless soundtrack of bird songs. The land, however, is not the only place where life is replenished in the spring and summer months. The ocean, with its seemingly unchanging surface, is also privy to the productivity of these seasons, especially off the coast of California, where the winds and deep underwater canyons provide the perfect conditions for upwelling. These coastal upwelling regions are relatively rare, accounting for less than 1% of the ocean surface, however, they are incredibly productive regions and contribute roughly 50% of the world’s fishing landings.
But before we dive below the surface, imagine the feel of a breeze across your skin. Winds create a powerful and direct effect on oceans and are an important force in creating currents. From the global circulation of entire ocean systems to small eddies nearshore, winds move water and its resident animals and plants in complex and interesting patterns.
In the spring and summer months, warm winds from the north blow parallel to the coastline towards southern California. When this occurs, an intriguing and biologically important event takes places. Affected by the rotation of the earth, these winds move water at right angles to the direction the wind is blowing, a phenomenon known as the Coriolis effect. Along the California coastline, winds that blow from the north drive surface waters offshore. As surface waters are pushed offshore, water is drawn from below to replace them. The upward movement of this deep, colder water is called upwelling.
Upwelling brings cold, nutrient-rich waters to the surface, which encourages the growth of large blooms of phytoplankton. The phytoplankton blooms form the ultimate energy base for large animal populations higher in the food chain, such as tuna, seabass, and even large marine mammals, like whales. Although an impressive biological event, this is not the only major consequence of upwelling because upwelling also affects animal movement. Upwelling moves nearshore surface water offshore and takes with it whatever is floating in the water column, such as larval young produced by most marine fish and invertebrates. These larvae are tiny, ranging from microscopic to the size of a potato chip, and they spend the first few weeks or months of life adrift in the water column. Upwelling that moves surface water offshore can potentially move drifting larvae long distances away from their natural habitat, to shelters such as a nearby oil and gas platform.
This past spring, I experienced the plethora of larval young swarming around California’s offshore oil and gas platforms. Although my dive partners and I focused our cameras on the anemone-covered beams, and the sea lion curiously swimming by, when we revisited our footage after the dive we found that many of the photos had been “photobombed” by a larva that landed on the lens! Even, when we exited the water, we noticed that our wetsuits were crawling with life. It was quite a shock to see thousands of tiny white shrimp and other larvae contrasted against our black wetsuits.
Offshore oil and gas platforms don’t cause upwelling but act as a landing site for those larvae displaced by upwelling. In fact, the vertical platform structures may cause a slight shift in current direction that mixes the surrounding ocean nutrients. This mixing, although small, provides the distribution of an important foundational food source for other, larger fish that call offshore oil and gas platforms home—which contributes to these offshore platforms being an important fisheries resource that can be disrupted if the platform is completely removed after it is decommissioned.Leave a comment
July 12, 2018
by Jared Huennekens
When I stepped into the Village Nurseries’ Horticulture Encounter, ‘Plants with a Purpose,’ at the Miramar Landscape Center and Growing Grounds, my senses felt bombarded with incoming stimulus. Like an owl who’s spotted a nest of mice, my head flew in circles absorbing an array of aromatic and beautiful plants.
The Encounter, curated by Suzie Wiest, a one stop shop for all your horticulture questions, boasts a robust collection of plants highlighting relevant landscape topics within San Diego county: fire resistance, edible flowers, fillers, deer and rabbit tolerance, pollination, pairings, and plants that promote well-being (health, productivity, and happiness). The San Diego office of Great Ecology (and the office dogs!) had the pleasure to learn and engage in a productive dialogue concerning these plants and the plants we use in our own projects and homes. Wiest has over 20 years of experience of experience in wholesale industry and her ability to navigate landscaping issues, pollination, native versus non-native species, and water resiliency was impressive to say the least.
For Great Ecology, the fire resistance collection titled ‘Blaze Battlers’ poses particular relevance to upcoming projects such as trail routing at Camp Ramah because of the recent wildfires in Southern California. Wiest developed a phenomenal collection to address our wildfire outbreaks and increase the ecological health of impacted spaces.
This collection was of particular interest to us, not only for large landscaping projects conducted at Great Ecology, but the yards and canyons in our neighborhoods. For me, this collection could mean a difference in the way my friends and family experience wildfires. At four years old, I was forced to evacuate my home because of wildfires in our area. Over the next 15 years, three major wildfires have occurred in my area burning down a few of my friends homes and favorite natural environments.
Many plants within the collection deserve mention on the merit of their beauty, aroma, and potential value as a sustainable solution (not specific to California). An exceptional succulent, the hybrid Aloe ‘Always Red,’ blooms masses of stark, blood-red blooms ten months of the year. Light frost, rain, and drought pose no threat for this South African native known as a magnet for droves of hummingbirds. The needle-like red and white bloom on the evergreen shrub Grevillea hybrid ‘Kings Celebration’ stood apart along with the Verbena lilacina ‘De La Mina,’ a fragrant purple bloom that attracts hosts of butterflies and bees. My personal favorite, the ‘Meerlo’ Lavender, displays an unassuming, untraditional cream, pale green color, but its aroma permeates my mind to this day, a week later.
Unfortunately, describing the beauty and smell of these plants is akin to a food critic describing a 12 course meal at Noma or google searching the Northern Lights. Nothing compares to the real thing.
The Great Ecology team enjoyed our visit and would like to thank Suzie Wiest along with the Village Nursery for allowing us to escape the routine of the work day, spend time outside learning about plants that influence our ecological works, and letting us take home a few plants free of charge!
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July 11, 2018
The Public Notice for the South San Diego Bay Wetland Mitigation Bank (Bank) Prospectus has been released by the U.S. Army Corps of Engineers for public comment. Great Ecology led the development of the Prospectus on behalf of the Bank Sponsor, the Port of San Diego (Port), and its release is the culmination of three years of collaboration between the Port and the Great Ecology team. The proposed 80-acre wetland mitigation bank is located within an 83.5-acre parcel owned by the Port, and if approved, will include the establishment, re-establishment, and rehabilitation of tidal wetland and upland transitional habitats. Tidal wetlands, and their associated buffers, provide important ecosystem services, support nursery habitat for fisheries of ecological and commercial importance, and act as key feeding and breeding grounds for coastal and migratory bird species. Great Ecology’s team includes ESA and RECON who provided engineering, hydrological, and restoration biology design.
The Bank Site is located within a former salt pond in San Diego. Historically, this salt pond was part of the Western Salt Work Company and served as a part of a network of condensation and crystallization salt evaporator ponds. Today, the Bank Site is largely upland and surrounded by large earthen berms, which isolates the interior of the site from tidal flows and prevents it from being a tidal wetland. The proposed project will restore tidal wetlands to the site by reducing the overall site elevation and breaching the surrounding berm to allow tidal flows to enter the site.
The completed project will include subtidal eelgrass, mudflat, transition zone, and upland habitats. The majority of the site’s historic perimeter berms will remain to provide a hydrological buffer around the site.
The Port and Great Ecology team are focusing on the next steps of the project planning, permitting, and bank entitlement process.Leave a comment
June 27, 2018
Great Ecology is thrilled to welcome Justin Apfel to the team! Justin is an ecologist with experience in wetland permitting, tidal and non-tidal stream assessments, GIS, subsurface contamination examinations, and stormwater management. He has previously served an AmeriCorps term and hiked portions of the Appalachian Trail (primarily in Virginia). In his free time, he enjoys snowboarding, fishing, and rock climbing. Justin is joining our Denver office.Leave a comment
June 21, 2018
by Jared Huennekens
Our environment plays an instrumental role in determining our ability to rise in social and economic class in America. Yet, not all environments are created equal.
By the year 2025, 65% of the world’s population is expected to live in urban environments. In America, people of color and low income Americans experience a disproportionate lack of green space within their communities–which have, in recent history, been urban environments. By instituting green space, urban environments may improve wellbeing of residents in disinvested communities, boost their economic performance, and address ecological concerns such as stormwater runoff and air quality.
Green space development attempts to balance economic, ecological, and environmental justice themes into a comprehensive framework. When green space development occurs, property values increases. For example, the High Line, an old train line converted into a green walkway in New York City, attracts millions of visitors a year and thus, despite a deep recession, between 2003 and 2011 nearby property value increased by 103% and $2 billion was invested in property development. Although property and business owners benefited an immense amount from the High Line, green space development aims to help disinvested communities – people of color and low income Americans who suffer from a disproportionate lack of green space.
Unfortunately, the High Line and other green space projects have acted as a catalyst for gentrification. As overall neighborhood conditions improve, rent increases for residents and they’re forced into communities without established support systems. Residents may find themselves separated from family members or friends, without community-based organizations like after school programs that provide additional education for children, with even less green space than before (re)development occured, and farther from work, health-care services, welfare offices, or healthful food. Without an emphasis on environmental justice–and input from the communities being impacted–green space development ignores the very people it aims to help. In addition, ecological considerations should motivate projects, instead of aesthetic prioritization. When beauty is prioritized, not only are there few ecological benefits such as improved water infiltration, stormwater capture, or localized cooling of air or water, residents are inhibited from recreational activities that can promote better physical health, improved community connections, and decreased stress levels.
In a Comprehensive concept planning of urban greening based on ecological principles: a case study in Beijing China, Feng Li et al. establish a green space framework aimed at long-term, achievable sustainability on the regional, city, and neighborhood levels. The regional level constitutes large scale buffer zones, forests, and farmlands on the outskirts of urban areas. When approaching city and neighborhood green space development, disinvested community priorities need to inform what type of green space development occurs. A bottom up approach ensures “just enough green space” will arise to increase the psychological well-being of residents and create a healthier ecological environment in the area, yet not cause property values to increase so much as to force residents from their homes. Feng Li et al. advise on the city level to create a green network system of wedges, parks, and green corridors that connects the regional and neighborhood levels, establishing migration pathways and habitats. For neighborhoods, utilization of vacant lots and greening sidewalks, medians, rooftops, and riversides has abundant potential for ecological and psychological health benefits. By breaking green space development into three categories, developers are better able to build connections between spaces, build a greater ecological vision for a region, and identify underdeveloped or unprotected areas.
When developers institute a bottom up approach, they’re placing the needs of the community before economic incentives by integrating the community into the development process. Developers need constant communication with community leaders before, during, and after green space implementation to design a successful green space that address community needs. Planners need to ask questions such as what their priorities are for improving the community, what type of green space they prefer, and what their major concerns are for implementation. For people of color and low income Americans, their list of priorities may rank environmental injustices lower than other wicked problems such as poverty, homelessness, education, employment, affordable housing, and mass incarceration to name a few. Resources directed towards disinvested communities needs to address issues most important to disinvested communities. Often, more pressing matters should take priority over urban greening. By asking community members what type of green space they prefer and their major concerns, planners can institute green spaces that maximize the wellbeing of residents. For example, a green walkway and cafe gears towards the needs of middle and upper class and may lead to gentrification in an area while cleaning up a toxic creek decreases exposure to harmful materials without increasing property value an exponential amount. When developers deploy this principle of “just enough green space” to mitigate the effects of gentrification, projects may not be economically viable because people don’t flood the surrounding area leading to stagnanet property value and business incentives. These projects address environmental injustices and the needs of community members without adding tremendous economic value to the area.
Street trees, lawns/parks, urban forests, cultivated land, wetlands, lakes, seas, and streams are identified as the seven urban ecosystems by Per Bolund and Sven Hunhammar. Each ecosystem prioritizes different ecological services in urban areas: air filtering, microclimate regulation, noise reduction, rainwater drainage, sewage treatment, and recreational/cultural values.
Although Bolund and Hunhammar identify those ecological services as most important, urban green space can provide other services such as food production, roof longevity, carbon sequestration, and soil erosion mitigation. Food production combines disinvested communities need for green space with another wicked problem: food insecurity and food deserts.
Ron Finley, who envisions a world where “cool kids know their nutrition and where communities embrace the act of growing, knowing and sharing,” promotes urban guerrilla gardening. Based in South Central Los Angeles, he found himself traveling great distances to find an apple without pesticides. Even though Beverly Hills is only a few miles away, South Central’s obesity rate is 10 times higher, which is correlated with a lack of access to healthful, affordable food. The Ron Finley Project transforms yards and parkways into vegetable and fruit gardens. Finley argues Los Angeles should utilize their 26 sq. miles of vacant lots, the equivalent of 20 Central Parks, by allowing people to grow food for the community and for themselves. Through projects similar to Finleys, urban greening has the potential to address multiple issues facing disinvested communities whether that’s food insecurity or their psychological and physical wellbeing.
Different types of green space facilitate different health benefits for nearby residents. Parks encourage physical activity. When children and adults have more access to parks and recreational facilities, more physical activity occurs and obesity rates decrease. Parks and other green spaces are shown to both aid social interactions (linked to improved physical and social-emotional health) and provide an area for residents to experience solitude. Increased exposure to green space rejuvenates residents, enhances contemplation, provides a sense of peace and tranquility, reduces stress, and builds a connection to nature. Vegetable and fruit gardens expose children and adults alike to learning about the food production process, expose them to foods they might not otherwise eat, increase opportunities to do physical activity in the garden, and foster community connections. Ron Finley exclaims in his TedTalk, “If kids grow kale, they eat kale.”
Although there are many positive benefits to urban green space, several negative aspects exist. For example, if developers use non-native vegetation when reviving the ecological health of an area, adverse effects may arise for the environment, including introduction of new weeds or pests. Whenever new ecological features are introduced, residents may suffer from unexpected noise disturbances, increased allergies, or bad odors from improperly managed stormwater conveyance or treatment systems. These annoyances are avoidable if an ecologist or knowledgeable landscape architect informs the development process. Further, there can be unintended economic impacts on residents. Unfortunately, the principle of “just enough green space” to discourage gentrification may mitigate growth, causing the projects to not be cost effective and therefore be rejected by city planners and other decision-makers. All of these factors need to be considered before developing green space in urban environments to ensure sustainable development that benefits communities.
No resource goes to waste in a natural environment. Urban green spaces, whether community gardens, wetlands, or urban forests, have the potential to transform a wasteful, inefficient artificial environment into a natural environment. Up to 85% of air pollution can be filtered out in a park. Tree cover can reduce total energy costs for heating and cooling by $90 per dwelling per year. And, wetland restoration has potential to treat wastewater and stormwater significantly before it re-enters streams or sewers while increasing increasing biodiversity. Urban greening diminishes the negative effects of urbanization, improves the well-being of residents, and enhances the economic performance of an area. Through this development, people are more capable to create healthier communities and rise in socioeconomic class.Leave a comment
June 14, 2018
By Gali Laska
Your local city park is likely playing a vital role in your city’s health, and probably your own mental health too. Parks and other “green spaces” help keep cities cool, and as places of recreation, can help with health issues such as anxiety and depression. Just looking at greenery can make you feel better! But in increasingly crowded cities, it can be difficult to find room for parks and other green spaces. About 66% of the world’s population lives in a bustling loud city. But do they know that the lack of green may be the reason they feel less motivated, happy and fulfilled?
Most likely not, considering that when architects and city planners initially created the blue prints for their cities, they didn’t realize it either. Something has to change, and it is changing—toward greener cityscapes. Great Ecology works everyday with different municipalities and businesses that need assistance in making their properties more ecologically friendly. This includes developing better management plans for city parks, converting nonnative landscapes to native landscapes to improve resiliency, developing mitigation plans, helping coastal areas plan for sea-level rise, and creating stormwater wetlands.
And, we hardly work alone in this. The importance of greener cities is being researched on many fronts, from ecological to psychological impacts.
Over the past 25 years, psychologists have begun to understand the impact that the urban environment has on its citizens. Researcher Colin Ellard, who studies the psychological impact of design at the University of Waterloo in Canada, found that people are strongly affected by building façades. He performed an experiment where individuals were instructed to walk past specific buildings while wearing a bracelet that monitors skin physiological arousal. When the subjects would walk past a long, smoked glass frontage of a grocery store for example, arousal took a dive and they quickened their pace, as if to get out of that area. As soon as they entered a stretch of restaurants their arousal picked up and their pace slowed down. Each restaurant was surrounded by various plants and other eye-catching additions to make for a more arousing place.
What do the findings of this study tell us? Colin Ellard shared the following sentiment “Historically, the attitude toward the importance of green space has been basically to consider the presence of greenery as an aesthetic nicety, rather than as something of fundamental importance to people’s psychological state.” We need to start building with the thought of mental and physiological health in mind, not just feel good aesthetics. Having more plants can lower blood pressure, reduce muscle tension, improve attention, and reduce the feeling of fear and aggression.
Studies have shown that patients recovering from surgery in a room overlooking trees recovered faster and with less fewer complications than those overlooking a brick wall. Having a greener environment not only affects mental health, but also physical health. In children, ADD symptoms are relieved after contact with nature. Green spaces may enable people to think more clearly and cope more effectively with life’s stresses. Overall green is good. Whether it means reducing symptoms or increasing happiness, the need for green in the everyday life is a necessity. Perhaps this is linked to what E.O. Wilson coined as “biophilia.”
Biophilia is the positive effect that being around blue water, green trees and space give us. It is also the love of earth and the environment. Biophilia suggests that humans seek connections with nature and other forms of life. It makes us healthier, more productive, and more generous.
That’s nice, of course, but how do we implement this in our cities?
Amanda Burden had a huge part of making New York into a greener city. Burden fought for the High Line and for making a public space for citizens to be able to enjoy the environment. Amanda said “Public space always need vigilant champions. Not only to claim them at the outsets of public use but to design them for the people that use them, then to maintain them to ensure that they are for everyone…Public spaces have power. It’s not just the number people using them, but the even greater amount of people that feel better about their city just knowing that they are there.”
You may ask: Does having a greener environment affect my social life? The answer is yes. When living the busy life, you might not have enough time to just be, and take in your surroundings, especially if your surroundings consist of cement and bustling streets. Even those of us who aren’t living in the city may feel stuck in harried lives filled with the need for speed and technology.
Most of us are constantly doing things that keep us busy—and as a result we don’t make time to stop and look around. If a city (or any other local government) fosters inviting green spaces that make it easier to have social interactions outside, mental health would likely improve.
Dr. Andrew Lee, a public health researcher at the University of Sheffield in England says: “If it’s a social space where people meet together and chat and go on walks, that kind of social contact and interaction builds social networks, that’s probably where the real impact is coming from that gives people a sense of wellbeing.”
While city officials have work to do, we need to spend more time looking out at the world instead of looking down at our screens. We need to surround ourselves with human interaction and nature so that our mood and our lifestyle improve. Making public places more accessible—and encouraging people to use them and letting them know how their lives are affected without them—can improve the health and well-being of citizens.
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May 23, 2018
Great Ecology is thrilled to welcome our newest team member! Jessica L. Foley, a former John A. Knauss Marine Policy Fellow and policy analyst with the National Oceanic and Atmospheric Administration (NOAA), is joining the Denver office. She has experience working in varied settings, both nationally and internationally, at the federal and local government level, in the non-profit sector, in private industry, and in academia on local to global issues. She has helped communities plan for sea level rise, create and implement invasive species management plans, integrate the use of green infrastructure, and maintain Clean Water Act (CWA) compliance. In addition, she has led research on the impacts of climate change on eelgrass (Zostera marina), which is the base of highly functional marine ecosystems along the U.S. coast. In her free time, Jessica enjoys exploring, hiking, and snowboarding in Colorado’s beautiful mountains and playing the violin.Leave a comment
April 19, 2018
By Liz Clift
Last month, we posted Part 2 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. And in February, we posted Part 1.
Now, we offer Part 3. As with Parts 1 and 2, points are based on the Hasbro website’s Scrabble dictionary, which assumes only the face value of tiles.
Adit (5 points) – an entrance, as to a mine
Arkosic (13 points) – sand that is rich in feldspar
Ctenidia (11 points) – a comb-like anatomical structure, such as a gill
Eelier (6 points) – resembling an eel
Related: eely, eeliest
Feldspar (14 points) – the single most abundant mineral group on earth
Meristem (12 points) – formative plant tissue containing undifferentiated cells
Notochord (15 points) – a flexible rod that exists at some point during the life cycle of all vertebrates
Parr (6 points) – a young salmon
Peat (6 points) – a soil composed of partially decayed vegetative material
Related: peaty, peatier, peatiest
Sculpin (11 points) – a type of fish that may appear in both freshwater and marine environments
Fun fact: Eelier is one of my favorite words, and although I don’t get to use it in an ecological context all that often (okay, so once, exactly, while talking with a volunteer at a marine life center about eels and wolffish), it is handy for getting rid of a surplus of “e” tiles and almost guaranteeing that someone will challenge you.
Study up on these words—I’m sure we’ll have more coming at you in the future.Leave a comment
April 18, 2018
By Liz N. Clift
This year, Earth Day (April 22nd) falls on a Sunday. This year, Earth Day is focused on plastic pollution. Plastics take many different forms—ranging from drinking straws and Styrofoam to mattresses and medical supplies to cigarette filters and shopping bags, and many more items we use on a regular basis. Since plastic is such an ubiquitous part of life, it’s sometimes easy to forget that plastic was invented just over a century ago in 1907.
Since then, we’ve produced 9.1 billion tons (8.3 metric tons) of non-recycled plastic. 5.5 billion tons of that has accumulated in landfills and the natural environment—and it’s estimated this amount will more than double by the year 2050 if current trends continue. The primary culprit in the increased plastic production is the rise of plastic packaging—in 2015, packaging made up 42 percent of the non-fiber plastic produce and composed 54 percent of the plastics thrown away.
This is part of what’s behind the various campaigns to reduce plastic consumption—ranging from plastic shopping bag bans (which, at least in some areas, is linked to increased rate in Hepatitis A outbreaks since those experiencing homelessness used these plastic bags to dispose of waste), plastic straw bans, and other single-use plastic restrictions or bans. And, it’s not just municipalities or countries enacting these bans. The BBC, which helped highlight the problem of plastic pollution through Blue Earth II has plans to eliminate all single-use plastics from its operations by 2020.
These efforts are not for nothing. The World Economic Forum estimates that by the year 2050, plastics will outweigh fish in the oceans. If you’ve ever done a beach—or a roadside or stream or playground—clean-up, you probably noticed that most of the things you picked up were plastic or plastic-lined. You’ve likely heard about the great Pacific garbage patch (now three times the size of France or a bit more than twice the size of Texas)—but did you know that there are five massive patches of marine plastics?
Birds, and other animals, can be harmed by these plastics. Birds may peck at plastics or swallow them whole. If you’ve ever done a clean-up and found a plastic product that looks like it has bite-marks all over it, this is likely from a bird pecking at it. Whales have washed up with bellies full of plastic. Turtles can become tangled in plastic causing them to die or grow deformed.
In addition, researchers have begun to find plastic in our food supply as well—and while this field is still new, and understudied, it may be a cause for concern since plastics contain known human carcinogens. One study indicated that consumption of shellfish means that an “average” European shellfish eater consumes 6,400 microplastics (defined in this study as smaller than one millimeter) each year. Other studies have found microplastics—which may be less than 150 micrometers, or roughly the width of a human hair—in tap and bottled water, sea salt, honey, and beer. This means that not only do we have little idea about the health implications of consuming plastic—we also don’t know much about how much plastic we’re consuming or the impacts of plastic-pollution as it moves through various trophic levels (i.e. – that salmon you ate is a predatory fish and accumulated toxins from things it ate before it was captured, through a process known as bioaccumulation).
Not only are plastics in so many products and foods we use daily, plastics can also pose problems when they are “biodegradable.” Biodegradable plastics (as opposed to other biodegradable products made without petroleum) create “fragments” of plastic more quickly than other plastics. These fragments can quickly deteriorate to microplastics, which can be harder to identify and clean up—in some cases you’d need a microscope to even see them. In other words, “biodegradable” plastic products may simply be another type of greenwashing—so, whenever possible, do your research and figure out if the product you’re considering buying—or putting in your compost pile—is truly biodegradable or not. By being an informed consumer, you can make choices that help reduce the plastic stream.
So, what else do we do?
There are a number of things you can do to both help clean-up plastic and reduce your plastic consumption. Here are a few:
All this week we’ll be posting more information about plastics on our social media—so be sure to check us out on Facebook and Twitter, if you don’t already follow us.
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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