Corridors, Highways, and Habitat (Oh My!)

(Right) Wildlife movement around a corridor - in this illustration birds fly along the interior of the corridor, deer munch on plants found on the corridor edge, and a bear meanders across the corridor. (Left) The illustration on the left shows more than one type of corridor. This image illustrates a portion of a network of forest corridors. It also shows a network of a human transportation corridors, or roads. Often times natural corridors are more curvy, while human-built corridors are composed of rigid geometries. These corridors cross each other on the right side of the illustration - below, I touch on how that crossing can work well and how it cannot work well.

“Highways, new plantations, the fencing-off of certain areas, the damming of water sources, and similar developments, crowd out natural habitats and, at times, break them up in such a way that animal populations can no longer migrate or roam freely. As a result, some species face extinction. Alternatives exist which at least lessen the impact of these projects, like the creation of biological corridors, but few countries demonstrate such concern and foresight."

-Pope Francis I, Laudato Si', par. 35

The biological corridor Pope Francis is discussing is simply a linear strip of habitat that differs from the land on either side of it. An animal's habitat is an area with the necessary conditions to support its survival. My habitat is where I live, and it can be described by what and who enters and leaves that space regularly and provides something necessary for me to function in that space. I have a daily range of motion that is included in that habitat, and, on occasion, I go beyond that daily range. However, there are places on this earth I simply cannot, nature willing, go to and thrive—like the bottom of the Mariana Trench or the inside of Mt. St. Helens. I tend to avoid those places. Animals in the wild are much the same - they live in areas defined by the habitat requirements of their species, and each species has a certain set of requirements for an area to be considered suitable habitat. Some species are more sensitive than others and they can rarely exist outside their habitat without pressing mortal danger, like some arboreal bird species. Some species are "multihabitat," and they are fine meandering through the landscape, whether in a field or a forest.

 

Wildlife corridor movement

Land bridge in NJ, USA. wikipedia.org, user: Doug Kerr

Corridors serve three primary functions. They provide a conduit for organisms and other non-living things (such as soil particles), they provide habitat for creatures and other life forms that live within them and along their edges, and they create a barrier or filter for anything in an area that is moving towards the corridor at an oblique or perpendicular angle, like the bear to the right. A corridor of high-quality habitat that is contiguous is ideal for the connection, dispersal, and migration of species populations, and it is vital for those species that are not "multihabitat." The continuity of corridors is often broken up by “Highways, new plantations, the fencing-off of certain areas, the damming of water sources…” to quote the Pope. In the United States, every day, 1,000,000 vertebrates traversing across the landscape are hit by cars (Forman). This incredibly large number is indicative of a serious problem of habitat fragmentation. Vulnerable animal populations attempting to obtain resources missing from their current habitat, to migrate, or to reach other populations of the same species in a fragmented landscape are more likely to meet a fatal end. It is not realistic to propose getting rid of all roads and vehicular transportation, but design solutions, such as wildlife underpasses and bridges, can make a significant difference in the survival of these creatures.

Church lands could be assessed for their spatial relationship to various corridors using mapping analysis. Where there is a lack of continuity, perhaps the land could serve as an auxiliary patch. This is why a major focus of the Good Land Project is to create a map of church properties, which will reveal ways that the land could do much more for the environment - and it may also reveal where land is already playing a critical role in the landscape and may be, at the least, helps increase the connectivity of a vital corridor by providing a habitat patch. Existing Church lands could be serving as crucial pieces of corridors and should be carefully approached with regard to land-use planning if they are. However, without a comprehensive map of the Church’s properties, we cannot know if this is the case.

Molly Burhans
goodlandproject.org

Sources:

[1] Pope Francis I. “Laudato Si’ - Encyclical Letter, On Care for Our Common Home, Pope Franci I.” Vatican: the Holy See. Vatican Website. Libreria Editrice Vaticana, 2015. Web. July. 2015.

This whole post is heavily influenced by:

[2] Forman, Richard T. T. Land Mosaics. Cambridge, UK: Cambridge University Press, 1995. Print.

Soil and Plants Need Each Other

streamline and turbulent wind around different windbreaks

It is common knowledge that plants need soil. However, not often enough is it asked; does soil actually need plants? The relationship between plants and soil is more mutually beneficial than most would think. Soil is the uppermost layer of the earth in which plants grow. It is a composite of rock particles, organic materials and microorganisms. Within the soil there is an entire complex ecosystem of microorganisms, insects, and burrowing critters—their activity is as vital to soil composition as are the nonliving (abiotic) components of soil. 


Floods spread water over a floodplain once soil becomes too saturated to hold additional water. Flood water moves across the earth and erodes soil as it washes over a landscape. Wind, which is also a fluid force of nature, can contribute to soil erosion as well. This is especially the case in certain narrowed areas of the landscape where wind funnels through a “corridor” – this increases wind velocity by reducing air pressure, a phenomenon explained by the Venturi effect. Some erosion is simply a natural process, but as with many things in nature, there must be a balance. Too much

Turbulent eddys form around obstacles

erosion leads to arid soils deprived of organic materials and incapable of supporting life. A cover-crop grown over an underutilized agriculture field can significantly preserve the soil's quality in the area and protect it from abrasive forces. Windbreaks which perpendicularly intercept prevailing winds in an open space also help protect soil, by decreasing wind velocity. These windbreaks can be trees, or even shrubby herbaceous plantings. Windbreaks created by trees in a field can be a critical way for increasing soil health by protecting surface soil from powerful windflows across a wide-open space. Adding vegetation can also protect soil from erosion caused by floods by giving the soil something to “grab” onto as floodwaters sweep an area. Some types of trees can also help decrease a local water table by taking-up water; consider that just one large tree can lift up an average of 100 gallons of water out of the ground.

We are seeing the effects of desertification driven by drought and decreased vegetation coverage in many areas of the world. Adding trees to a space is just one way to increase soil health and combat this ecological threat (a few arboreal-lacking biomes are exceptions). Without vegetation, soil “dies” and without soil, the vegetation dies--once their relationship is disrupted it creates a dangerous negative feedback loop. The maintenance of healthy soil is essential to supporting a functional ecosystem and is also extraordinarily important for food security, as well as preventing species extinction of plants and the animals that rely on those plants. These and other considerations should lead to the realization that soil health is vital for our own survival and we should approach landscape design and land-use planning with that in mind.


By Molly Burhans
goodlandproject.org

Sources:
[photo quote] Pope Francis I. “Laudato Si’ - Encyclical Letter, On Care for Our Common Home, Pope Franci I.” Vatican: the Holy See. Vatican Website. Libreria Editrice Vaticana, 2015. Web. July. 2015.

This whole post is influenced by the work of Richard T. T. Forman.

A nutrient rich upper-layer of of soil, or organic layer, mingles with mineral rich parent material from the lowest layer of soil. In this image it combines and coalesces overtime to form this fascinating stagnogley soil. Stagnogley soils are loamy or clayey soil with a relatively impervious subsurface horizon. The colors can indicate the aerobic conditions of soil with some iron content--this soil was likely very moist/waterlogged for extended amounts of time.

Perspective -- Laudato Si' and Landscape Planning and Design: Great Hopes for Global Environmental Change

Baby Cardinal in Hand. Credit: Public Domain

Laudato Si’ is a call from the Catholic Church for all citizens of the earth to care for all of God’s creation. It is a landmark piece of ecclesiastic writing. This encyclical is sobering, full of truth about the problems of human-driven climate change, and it is also incredibly hopeful. To put the hopefulness in perspective; Laudato Si’ made addressing human-driven climate change a moral imperative for the 1.2 billion Catholics in this world—and they are doing things. Catholics are building rain gardens, fasting and praying rosaries for climate change action, and planting trees alongside ideas for a brighter, more sustainable future for the planet. Some Catholics are taking the Pope’s message more seriously than any of the previous calls to climate action - and when that “some” is a subset of 1.2 billion people throughout the world, the potential impact is huge. I find even more hope in realizing that it is entirely possible that Catholic-affiliated properties comprise the world’s largest non-governmental network of landholdings. Managing just a fraction of this land in an environmentally could have a global impact on the direction of climate change.

Leading up to the release of this encyclical, I found myself inspired to deepen the relationship between my faith and my education at Conway. Since its release, I have come to grasp in a very profound way how ecological design truly is a form of charity—it constantly gives to the communities that encounter and embrace it, as well as the ecosystems it lies within. The landscape is a place where the known and the unknowable can couple together to produce great designs. Landscape planning and design are co-creative acts because they inherently involve many elements beyond the designer’s control.  The verdant areas of academic explorations between faith and design illuminate questions about co-creative spaces of the landscape designer and how the controllable and uncontrollable work into the choreography of plans and designs across a dynamic landscape. Serious academic discussions about the spatial elements of virtuous acts and how spiritual paradigms intersect with design practices and theory provide fertile ground for future explorations. I am glad that Laudato Si' has helped till the soil for more of these discussions.

 

This Pope hears the cry of the poor and vulnerable in the face of human-driven climate change. I heard this cry in the Sahel of Mali, in West Africa, while working on agriculture and water infrastructure planning. It’s the cry that “if there is no rain, we die,” as well as a cry that braces for yet another devastating typhoon. It’s the cry of the victims of violence caused by climate-escalated conflicts related to unjust resource distribution. While climate change may be the most difficult struggle of our times, the potential positive impacts of the Catholic Church with its massive landholdings, large population, and organized structures rallying behind the cause of climate change action is a source of incredible hope. Part of that hope for me is that the world will continue to move toward a future in which the lives of all people are improved, and that consideration for the lives of the most vulnerable among us are placed at the forefront of discussions about planning and design.

Author: Molly A. Burhans
goodlandproject.org

Photo credit: Chris Hendershot, 2015. Well Digging in the Djangoulas [chris.g.hendershot at gmail dot com]. This photo was taken during our time in Mali in our final semester at the Conway School, while partnered with Mali Nyeta. The village residents had to dig 9+ meters to reach the water table and they said the distance was increasing every year. This decrease in water table is due to increasing drought, deforestation and desertification in the Sahel.

A Rain Garden's Ripple Effect: An Introduction to Green Stormwater Infrastructure and Why it Matters

CSO, or Combined Sewer Overflow dumps excess waste water into a nearby water body, posing a serious hazard to the health of the environment and people in the area.  [1] 

Water that falls on built surfaces, such as parking lots or roofs, usually finds its way into a storm drain and those drains either empty directly into a natural water body or into a larger sewer system. When the larger sewer system is overloaded during heavy rains it will dump its untreated excess water into the environment. If the system is a combined sewer overflow it will expel a mixture of runoff water, human waste water, and (sometimes) industrial waste water, directly into natural water sources, such as local lakes, rivers, and streams.

Riparian zone schematic typical of the Florida Everglades. [2]

Water that falls across a paved surface generally collects salt, petrochemicals, and other pollutants directly from asphalt and whatever has leaked out of on-site features, such as automobiles. Having this hazardous waste-water dumped directly into a natural water source poses a serious threat to the aquatic ecosystem as well as to residents and farmers that encounter the water body. Riparian zones, the area near the banks of waterways, often serve as habitat and migratory pathways for numerous threatened and endangered species. It is important to approach landscape planning and design with sensitivity to the consequences of point-source pollution to these areas, caused by adding water volume and pollution runoff into a sewer system.

Another consequence of directing water into storm drains is that the water that would normally be falling on the earth’s surface as rain and locally and being absorbed into the watertable is running off an area and being redirected directly into water bodies. When green stormwater infrastructure is installed the ecosystem’s natural hydrological processes remain more intact due to offset of rapid water input to waterbodies during rainstorms (which also means decrease in flooding, especially on downstream properties).

  A bioretention system, or rain garden, in Oregon, US, decreases runoff.*

An example of green stormwater infrastucture is an infiltration basin. These are created simply by grading the landscape’s topography towards an area where the water can collect and sink into the ground. The intercepted water no longer goes straight to a natural water source. The plants included in one of these intercepting depressions can be phytoremediators--meaning they remediate the soil from many of the harmful chemicals now being directed into the storm water catchment area.

The primary result of the addition of green stormwater infrastructure to a landscape is that water is slowed, it sinks and recharges the water table, and the toxic chemicals in it are filtered or remediated before it reaches an aquatic ecosystem.

Because of green stormwater infrastructure, the delicate aquatic ecosystem is no longer bombarded with dirty water from the property during heavy rains.  The pipe from drain to output area may become almost negligible to maintain in price. This can save tens of thousands of dollars in the long run, and this saving adds up quickly when many properties are being considered at once. To give an idea - as of 2008, the total reported water infrastructure needs for the United States included $63.6 billion for combined sewer overflow control and $42.3 billion for stormwater management. Green stormwater infrastructure reduces the need for complex sewage systems and uses natural processes to treat storm water throughout the landscape.


Author: Molly A. Burhans
goodlandproject.org


Sources

[1] Hartford, CT Combined Sewer Overflow. © Molly Burhans, 2015.

[2] Wikipedia. Riparian zone schematic typical of the Florida Everclades. From '' The Impact of Federal Programs on Wetlands - Vol. II'' source: http://www.doi.gov/oepc/wetlands2/images/fig12-1.gif {PD-USGov}

[3] A photograph of a bioretention system, or rain garden, in Portland, Oregon, US. Wikipedia, User:
EmilyBlueGreen.