Land System Science and Our Urban Landscapes
Land Use Cover Change and Climate on the Lewis & Clark College Campus
Land Use and Global Environmental Change
All aspects of the earth system -- atmosphere, land, oceans, watersheds, ice covers, and the biosphere -- are essential to the health of life on earth and play a role in our changing climate. All these components of our environment are affected by human activities at all scales.
Land is perhaps the most clearly changed by human activities. Cities are the places where we can most see human changes to the landscapes across the globe as well as over time. Technological advancement, population growth, and urbanization all lead to the expansion of urban areas. Urban landscapes form their own climates, thanks to buildings, paved surfaces, waste and heat emissions, thinned flora and fauna, and impacts on waterways.
Urbanization has increased rapidly over time and, until only about 2007, the majority of the globe's population lived in rural areas (Ritchie 2018). Urban climates are so different from their rural counterparts and in significant ways that impact their increased population density, built land-cover materials, and pollution generation has on their inhabitants' health and the global climate. With urban development often comes increased transportation needs, industry, consumption, ecosystem impacts, air and water pollution, the urban heat island effect among other negative environmental changes. Yet cities also offer the potential to concentrate human populations and decrease transportation needs as well as free up rural spaces to be better preserved.
While significant overall, broad statements like these ignore the details and complexity relevant at smaller scales. One study looks to move beyond the "urban-rural dichotomy" by examining the magnitude of land use conversions in Europe. They found that "most urban land changes between 2000 and 2014 come in small incremental changes, rather than sudden large-scale conversions from rural to urban land" and urban land use varies greatly even within 1 square kilometer (Vliet et al. 2019). This article argues for a mosaic of various land-use classes and intensities.
Making the links between human societies, land use, and environmental harm is essential to being able to understand what tradeoffs are relevant as stakeholders and environmental leaders move toward a more sustainable future. The field of land system science does just that: seeks to understand the drivers of this land use change and apply that knowledge in designing sustainable transformations in land use (Verburg et al. 2016).
"Land use can be seen as the largest geo-engineering project in which mankind has engaged. Land system science can act as a platform for integration of insight from different disciplines, design of novel land system solutions and for translation of knowledge in action" (Verburg et al. 2016)
Studying Land Use Change
Land use and land cover, and changes in these over time, are traced globally by satellite data to a precision of about a 30 by 30 meter square.
The map to the left provides land use data from the National Land Cover Database (NLCD), compiled by the Multi-Resolution Land Characteristics Consortium ( MRLC ).
To connect our neighborhoods with global trends and understand how we as individuals fit into land systems, we must check these overall data with the true land covers and microclimates we experience.
- At the local level, what relationships exist between land use cover and climactic conditions like temperature and humidity?
- How has our local environment changed over time? How are those changes visible in land cover and microclimate data?
- How can data achieved through citizen science connect us with global change and contribute to the greater project of "greening" our land use?
Portland: Green or Grey?
Portland is an intriguing place to study urbanization, land use cover change, and climate. Nicknamed Stumptown, the area was first cleared of trees to make way for urban development, yet it is now known for its greenness - both its urban forest and its environmental engagement.
Portland's story illustrates the importance of land system science in the ability to "green" cities: making our use of the land less harmful for our communities and our planet.
The urbanization of large metropolitan areas like Portland happened over time...
...yet these changes happen at the micro-scale. Portland, like all urban areas, is a patchwork of varying land uses and climates. Exploring Portland - from Forest Park to Downtown - involves moving in and out among a variety of landscapes.
Land uses are indicated on the neighboring map in different colors: reds indicate urban land cover, greens indicate forested land, yellows are agricultural lands, and beige-colored squares show various shrubs and herbaceous land cover.
Zooming In on Lewis & Clark College...
Land Use and Cover Change Contextualized on the Campus of Lewis & Clark College
How can we examine land use cover change at a more comprehensible scale?
Land cover is important at very large scales, from global to national. It can be hard though to really grasp the long term changes and on the ground impact at such large scales. In order to better understand what land cover change looks like over time, and how it impacts microclimate, we are grounding this topic in the Lewis & Clark College campus. Examining change at this scale is very manageable and helps one to better understand what is happening. Because it is a college campus, there are carefully documented historical photos that help show land cover change over time and gives us a real sense of change over time. Additionally, this area has a wide variety of ground cover types and provides an interesting setting to study how land cover change, ground cover, and micro climate are related.
In this context of the Lewis & Clark Campus, we conducted basic research on land cover and micro climate and focused on these questions:
- What had land cover change looked like at L&C through time?
- What relationship can we see between microclimate and land cover?
Lewis & Clark Over Time
The first aerial photos date back to 1936 where the estate gardens and the stables are the most visible aspects of campus.
By 1953 we see that the campus has expanded to include a track and dormitories, but the area around campus is still fairly isolated and forested.
By 1967 we see that the complex of dormitories has dramatically expanded, and that campus is far less distinguishable in amount the trees as the neighborhood has also grown over the years. The land cover is changing from forest to urban.
This photo from 1983 really helps illustrate the urbanization of the area. The green areas are saturated in pink, showing all the developed areas in grey, though the the green-yet-developed gardens and track also appear in pink.
Jumping ahead to 2001, we see the first full color image of campus, and a version of campus not too far off from the current day. This is also the first time that we can compare the areal photos to NLCD land cover maps.
- NLCD stands for the National Land Cover Database is an ongoing land cover modeling production effort
- This database categorizes 30x30 meter pieces of land into basic land cover categories
This map demonstrated the NLCD land cover classification overlayed with the L&C campus map. The data is from from 2000, right around the same time as the previous aerial photo was taken. This classification shows that campus is primarily classifies as Developed Open Space, Developed Low Intensity, and Medium Intensity, with pockets of Evergreen Forest (with small bits of Deciduous and and Mixed Forrest)
Land Cover and Micro Climate
This map now brings us to the second of our focus questions:
What is the relationship between ground cover and micro climate?
The black dots on the map represent the sites that were surveyed for information on the micro climate and ground/canopy cover. Through these cites we explored how these two things are related
Field Data
Research Methods
To better explore the LUCC and its impacts at the scale of Lewis & Clark, we conducted research on microclimate and ground cover for 14 sites across the college campus as well as the nearby River View Natural Area. For the microclimate study we monitored the microclimate at each site for the same 24-hour period using Kestrel Drops. For the ground cover study we collected observations on ground cover, canopy cover, and classified the locations by MUC codes (Modified UNESCO Classification Codes) to determine the land cover type.
Preliminary Findings
The data that was collected does have many limits, so the results aren't concrete findings, but they can demonstrate a relationship between micro climate and ground cover.
Conclusions
This data is very limited in scope and scale and even admittedly in accuracy, but it is a demonstration that micro climate is effected by ground cover and canopy cover. This exploration is not necessarily useful for the specific data, but for the ability to contextualize the broad topic of land use and cover change into the more understandable and small context of a college campus.
Beyond Lewis & Clark College
Our look at land use cover change on the Lewis & Clark College campus can serve as an example of citizen science and as a model method for data collection at other sites. Using historical photos to give greater meaning to current looks at LUCC can also be helpful when looking at other locations with long histories of human-environment interaction.
This study is limited largely by user error and difficulty attaining reputable and accurate data. Since there were so many opportunities for error, most of the data is difficult to analyze and achieve accurate understandings of. However, there are general trends present in the data that are at least somewhat reliable and perhaps offer insight into some of the pros and cons of citizen science.
The importance of citizen science
Citizen science engages those most concerned with their communities and provides opportunities for participants to make a direct contribution to research, increase their scientific understanding, and immerse themselves in learning about environmental issues (Earthwatch Institute 2020).
Looking at changes from multiple scales allows us to better grasp global-scale changes and make sense of what we observe. Although looking at a single college campus might seem insignificant, looking at Lewis & Clark, a site which we are very familiar with, makes our findings that much more relevant, important, and easy to understand. Lewis & Clark’s diverse land cover use makes it perfect for studying a micro version of macro trends and LUCC/climate connections. How have microclimates changed on the Lewis & Clark campus over time? How can we use historical change patterns to make better land use change decisions in the future?
Acknowledgements:
Thank you to Jessica Kleiss for guiding us through data collection and analysis and for our classmates in 220 for collectively gathering data and for supporting one another through our analyses.