Maxwell Creek Watershed Project Field Files Part 2: Developing surveying methodologies 

The project takes a watershed-wide scope to improve understanding of both existing and historical ecological conditions. The first question we aim to answer is: how has modification via forestry, fire, wetland drainage, etc. influenced hydrological dynamics, availability and quality of freshwater (i.e. source drinking water), and local forest ecology? We seek to find answers to this baseline-informing question through field-based research. We will then apply findings to inform the design and implementation of management prescriptions to answer our second question: what can restoration practitioners, land managers, and other experts do to enhance ecological integrity while also increasing community climate resilience? 

How would you describe your role with the Maxwell Creek Watershed Project?

I joined the team to help with geospatial analysis and data management. Because of the way the project evolved 一 I think primarily due to the restrictions of covenants having implications for implementing potential management prescriptions 一 my role has evolved to also include the development of an observational study. This has involved establishing research plots to get a sense of existing conditions across key parameters including canopy closure and soil moisture availability. 

“Section 219 of the Land Title Act authorizes the government, a Crown Corporation or Agency, local government, and other entities designated by the provincial government to enter into conservation covenants with property owners to help conserve their land. Covenants are registered against a property’s title and restrict the use of the property, typically to protect a natural or heritage feature or value” (BC Assessment).

The restrictions imposed by conservation covenants have been designed to protect ecologically sensitive land from development and other disturbance. However, sometimes these restrictions also limit the implementation of restoration activities, such as tree thinning in overly dense second, third, and fourth growth forests.”

– Shauna Doll

Ultimately, my contribution to the project will result in the development of an open source story mapping framework. This is also being referred to as a “data portal” by other members of the project team. It will present the project background and methods in an open and accessible online format, though the primary audience is  likely to be technical practitioners. 

What research questions is the Maxwell Creek Watershed Project attempting to answer?

The project takes a watershed-wide scope to improve understanding of both existing and historical ecological conditions. The first question we aim to answer is: how has modification via forestry, fire, wetland drainage, etc. influenced hydrological dynamics, availability and quality of freshwater (i.e. source drinking water), and local forest ecology? We seek to find answers to this baseline-informing question through field-based research. We will then apply findings to inform the design and implementation of management prescriptions to answer our second question: what can restoration practitioners, land managers, and other experts do to enhance ecological integrity while also increasing community climate resilience?

What methodologies are being used to answer these questions?

A literature review 一 considering existing baseline documentation and  perspectives of various local stakeholders 一 was the first step, and has been a continuing exercise as we develop methodologies. The second step is mobilizing available geospatial information, including  layers from various sources, such as recent LiDAR data generated by a geophysical engineer living at the border of the Maxwell Creek Watershed, to conduct geospatial analyses. The third step is implementing the on-the-ground observational study to establish  baseline conditions and inform the design of future management prescriptions (e.g. restoring drained wetlands by altering human-dug channels and ditches; thinning overly dense third-growth forest, ect.). Technically speaking, we are implementing a stratified random sampling design taking a two (2×2) factorial approach, contrasting open versus closed canopy and wet versus dry site conditions. Baseline data is currently being collected to paint a general picture of how conditions vary across those gradients. 

The baseline or reference gradient will allow us to identify characteristics of the forest in the context of local light, soil, and moisture conditions. This will help us design appropriate goals for restoration. This is key, because restoration ecology can be challenging. Whether a wetland is being restored, the way water flows across the landscape is being altered, or, the density of a forest is being reduced, one can anticipate certain effects, but until they are implemented there is always a bit of guesswork involved. In this project, an amazing amount of work has been done looking purely through the lens of LiDAR to develop a study design that maps out existing conditions and tests some of the assumptions we have about what potential management prescriptions might achieve. We can ask questions through the lens of existing conditions like: What happens if the forest canopy is open? Does an open forest canopy mean a denser understory? Does that, in turn, mean higher or lower levels of soil moisture sustained throughout the year? 

How were these methodologies developed?

The 2×2 factorial approach parallels the methods used for my master’s research, which examined the impact of seasonal drought on flowering plant communities and bumblebee populations within the Coastal Douglas-fir biogeoclimatic zone (Simon, 2020). For that study I was interested in contrasting the intersection between soil moisture availability and disturbance, resulting in four extreme site conditions: 1) dry semi-natural environments (woodlands and rock outcrops); 2) wet semi-natural environments (wetlands); 3) dry modified environments (disturbed upland areas such as clear-cuts); and, 4) wet modified environments (rural areas including gardens, orchards and fields). I established six sites per condition, for a total 24 sites, to collect data and investigate the relationship between the intersecting factors. Some important findings emerged from that study, including predictions about the abundance and decline of various plant and bee families under the drought conditions expected due to climate change.

Designing a study to differentiate effects of light and moisture 

In developing the study design for Maxwell Creek, the same model used in my master’s research was adapted, though it could also be deconstructed into a gradient based approach. The 2×2 factorial will allow us to get as close as we can to isolating the conditions of interest, which as mentioned above are canopy coverage and soil moisture. Canopy coverage was chosen as the first condition to align with the restoration goal of opening forest canopy/decreasing density to approximate a more mature forest structural state. Soil moisture was chosen as the second condition in alignment with wetland restoration goals. Together, these restoration goals are expected to increase abundance and diversity in the understory and slow water movement across the landscape, thus reducing risk of drought, fire, and water supply instability.   

Role of remote-sensed data

Something that differs between the approach taken during my master’s studies and the Maxwell Creek project is the inclusion of LIDAR data. For my study, I relied on Terrestrial Ecosystem Mapping (TEM) (Madrone, 2008) and other approaches to stratify the landscape. Conversely, the Mount Maxwell Project has benefitted from LiDAR models. To stratify open canopy versus closed canopy condition, we subtracted the digital elevation model of Maxwell Creek Watershed from the digital surface model.

Digital surface model (DSM): a representation that captures both the environment’s natural and artificial features. It includes the tops of buildings, trees, powerlines, and any other objects. Commonly, this is interpreted as a canopy model and only ‘see’s ground where there is nothing else above it (modified from Up42)

Digital elevation model ( DEM): a representation of the bare ground (bare earth) topographic surface of the Earth excluding trees, buildings, and any other surface objects (United States Geological Survey) 

To stratify wet versus dry sites, a raster layer representing the soil moisture regime was derived from a terrain analysis of LiDAR data. We did this by extracting everything that was upslope or “water-shedding” into one layer, and everything downslope including flat areas, ravines, gullies, and other depressions on the landscape into another, thereby segregating the contrasting conditions. Finally, we intersected all four resulting layers delineating the four possible conditions: 1)  relatively dry, open canopy; 2) relatively dry closed canopy; 3) relatively wet open canopy; and 4) relatively wet closed canopy. 

Stratification map: Bright red = Open-dry site conditions;  Dark red = Closed-dry site conditions;  Bright blue = Open-wet site conditions; Dark-blue = Closed-wet site conditions; Black = Area excluded based on exclusion criteria; Basemap: 1 m Bare earth hillshade

Prior to identifying potential study sites, some a priori exclusion criteria were implemented. For example, we included a 10 m buffer around roads to avoid edge effects. Next, we implemented balanced acceptance sampling, a geometric algorithm that produces what is essentially a simple random sample with better spatial balance (i.e. avoids dense clusters of points in close proximity to each other). This yielded 400 potential sites for the observational study, the majority of which were rejected based on a set of a priori selection criteria.  For example, some sites may be completely inaccessible for sampling or the LiDAR may have accurately detected an area as wet, but it may also be very rocky and thus not ideal for assessing soil moisture variability. As such, it was essential to go out in the field  to run through a site selection procedure.  

Ground-truthing 

When ground truthing potential study sites, it is ideal to visit them in the sequence generated to achieve a spatially balanced final sample. The best way our research  team could do this in the field was to divide points into clusters and move through them in sequence.  At each site we ran through the selection criteria and ultimately identified and established 10  permanent plots within each of the four conditions for a total of 40 plots. 

At each plot we  installed flagging tape to designate its centre and cardinal points where two intersecting transects will be established to measure soil moisture availability using a soil moisture probe and conduct percent coverage vegetation surveys. The plots will also be sampled by forestry practitioners, who will measure the amount of coarse woody debris/fine fuels (CWH) and the diameter at breast height (DBH) of trees within each plot. Other factors that are being measured include decomposition rates and the amount of light breaking through the canopy. We targeted open and wet conditions as potential proxies for the ideal state we might want to achieve via forest and wetland restoration measures. 

Because this is an observational study, we are not controlling variables to an extent that we can determine causality. Instead, we are investigating how conditions co-vary in relation to each other. For example, if there is a dense understory, does that correlate with an open canopy? If those two things correlate, do they also correlate with more elevated soil moisture levels in the late season when drought sets in? 

Further down the road, we will produce regression models; generalized, linear, mixed effects models. There is a whole suite of possible models we might apply depending on the independent and response variables to better understand correlations between these different conditions, and perhaps extrapolate our findings to potentially apply to other, similar sites within the region.

What are the expected outcomes of the project?

As mentioned throughout this article, we aim to implement restoration measures that will both help restore ecological integrity and to serve as a demonstration for future projects. The scale on which we are able to implement said restoration will depend on the resources available and whether permission from property owners/managers is granted.  This is the nature of restoration; it is a careful process with a great deal of learning and observation. 

In addition to restoration treatments, one of the big intended outcomes for this work is the development of recommendations for North Salt Spring Waterworks, who owns the property. When this project was conceived, the team wanted to take a no holds barred approach to envision what could be possible if all required resources were available. This approach was meant to define the project by possibilities, as opposed to limitations. In this way, it is aspirational–imagining a new way to manage land outside conventional extractive paradigms. 

Sharing what we discover

All of this information (i.e. overview of methodologies, analyses, results, barriers, and recommendations) will be compiled into a publicly available report, with all data from the observational study stored in the online data portal with the aim of creating a framework that is easily replicable. While it is unlikely to be perfectly reproducible, the idea is to provide vignettes, or key project facets summarized in a succinct and easily understandable format accompanied by visualizations/story maps. In this way, if the Maxwell Project eventually comes to some sort of conclusion 一 and I say if here because restoration work generally needs to be continuous over the longterm to achieve desired ecological outcomes 一 the framework will live on, evolve, and become the “source code” so to speak for future projects.

Finally, an outcome that is already coming to fruition is the establishment of a community of practice that includes folks from organizations like Raincoast, Brinkman, Transition Salt Spring, and IMERSS. Having all these skilled experts and practitioners working together creates  a  broad horizon of possibilities to continue to adapt these frameworks and tools. So along with the very specific technical framework that will come of this project, there is  this more social, abstracted framework that is evolving in tandem. That will hopefully serve as a resource for communities in this region to use in the future in a whole suite of different settings.

About Andrew Simon

 Andrew Simon is an ecologist with over a decade of experience studying British Columbia’s interior and coastal ecosystems. His passions lie at the intersection of natural history, community-based research, and biodiversity data science. Beginning with an apprenticeship to lichenologist Trevor Goward, his studies have since progressed through a dynamic career in the environmental sciences, working with NGOs, First Nations, academe, industry, and government. In 2020, he completed a MSc in Environmental Studies at the University of Victoria, with a focus on the implications of seasonal drought for plant and pollinator communities in the southern Gulf Islands. Beyond, Andrew continues to pursue his interests exploring the multidisciplinary, cross-cultural, and transboundary dimensions of biodiversity research in the Salish Sea.

Andrew is most well recognized for his commitments to community-based biodiversity research as the curator of the Biodiversity Galiano project, for which he was recently recognized with an Islands Trust Community Stewardship Award. He is also the president of the Institute for Multidisciplinary Ecological Research in the Salish Sea (IMERSS). Symbiosis is the notion that inspired his love of natural history to begin with, and it is this notion that continues to inspire his local and regional commitments to community science.

References and Reading

Simon, A. (2020). Water into nectar: The effects of seasonal drought on bumble bee and flowering plant communities (Unpublished master’s thesis). University of Victoria. Victoria, BC. https://dspace.library.uvic.ca/handle/1828/11837

Statology. (2021, May 13). A complete guide: The 2×2 factorial design. https://www.statology.org/2×2-factorial-design/

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