Remote Sensing

I’ve been cutting my teeth on remote sensing in the ACME Lab this week. We have camera arrays and GPS collars deployed in BC and Alberta, and lots of vector layers and  landscape-classification schemes to populate our analyses. What we still need are other landscape level data including vegetation indexes and snow cover. I’ve been exploring remote-sensing software and data-sources to find useful methods of creating these data for our lab.

Remote sensing and GIS analysis are different beasts. Most GIS data I use for landscape-level descriptions comes from publicly-available datasets that have been cleaned and prepared. Data is continuous across large regions, raster-layers usually have single bands, and interference from other stuff in the dataset is minimal. Remote-sensing data, by contrast, comes in 4-to-13 band “stacks” of rasters, each with different information that can be used to build images. Data is downloaded as individual images, and images from different dates are often used to cover an area. Imagery from different dates is used because most satellites (Landsat, Sentinel) record data in vaguely north-south flyover routes and visit adjacent east-west sites later than those along their immediate route. Cloud-cover  presents a common challenge – clouds beat satellites in remote-sensing rock-paper-scissors – and extra mathematical do-dads can be employed to mask or filter-out clouds, and fill in gaps with data from other images. The payoff – after acquiring, compiling, and cleaning images – is observations on light wavelengths from deep blue to thermal infrared that can be used to measure and describe landscapes.

Lots of software exists to run remote-sensing applications. ENVI is common proprietary software I’ve used in geomatics labs, and ArcGIS allows common remote-sensing applications. From the open-source world, R and the QGIS-GRASS-SAGA suite offer many tools. Online, Google Earth Engine offers easy viewing of remote-sensed data, and image manipulation and downloading in JavaScript (no GUI!). The US Geological Service offers image downloads from almost any satellite platform out there – every time I use this service I whisper silent thanks this hasn’t been cut or moved to Kansas (like the USDA) by the recent US Administration that Shall Not be Named.

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So many dataset options!

 

I looked at Google Earth Engine first, last year when I needed an NDVI layer for the Victoria region. Earth Engine loads imagery across the entire map-window from the specified time-period, and some datasets add code to apply a cloud mask, clipping out obscured portions of images.

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A composite Landsat 8 image of Vancouver Island from 2015-2018 produced in Earth Engine without a cloud-mask applied.
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The same image, with a cloud-mask applied.  In some places, clouds are filtered out and landscape details remain visible; in other places, the entire image is removed. Extra images can be added beneath these holes to create a composite cloud-free image.

No graphical-user-interface (GUI) exists in Earth Engine for viewing individual images, clipping output by the bounds of a study-area, or even downloading what you see on the screen. Earth Engine is approachable off the get-go with an planet full of images almost seamlessly displayed, but requires a steep learning curve to understand and investigate the data being worked with. I learned enough JavaScipt last year to view a series of images from different sampling times and download an Enhanced Vegetation Index (EVI) dataset for Victoria. Because I’m working with smaller-scale data the size of a few satellite image tiles, I prefer downloading images directly and working with them in desktop software. If I learn JavaScript in the future, this may change.

I picked up QGIS and GRASS next, because they have a strong online following, ample installed remote sensing tools, and more tools available as plugins. QGIS and GRASS GIS exist as separate software, and as a merged program that uses the interface of QGIS but requires uploading of anything worked with in GRASS to a seperate file structure. When I started GRASS in QGIS, the immediate loading stage crashed on “Step 2”, every time I tried to set a coordinate system for the project. Not a major hiccup, and I started working with images for the afternoon. I came back the next day to find the loading stage crashing on “Step 1”, every time I tried to create a new project. I searched online for a solution, then put QGIS and GRASS down and picked up Arc.

ArcGIS (ArcMap, desktop) seems to work as basic remote-sensing software. It’s not set-up to the teeth like other proprietary software, but it offers a good structure for organizing multi-band images. For my entry-level remote-sensing tasks, I’m looking for software that lets me easily load images, remove or filter out cloud-cover, and apply raster math to image bands to calculate NDVI and other spectral indexes. Once I get a handle on these, I’m going to try some supervised image-classification and analysis of change over time. I think Arc will be up to the task.

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NDVI mosaics for the northern Rocky Mountains from May to August 2019. Sentinel-2 imagery.

GCA – Grasses

In June and early July, our restoration team had time to start working on bonus projects. When monitoring vegetation in the Nuts’a’maat Forage Forest in June, we identified and recorded herbaceous plants and shrubs, but a glaring hole was left in our data collection – grasses. I had experience staring at grasses till my eyes bulged out (maybe that was from the noon-day heat in the exposed meadows..) in central Saskatchewan, and Adam is an all-round plant-whiz, but neither of us were able to confidently identify the majority of grasses on our restoration sites. The danger of being able to identify only some of what you see is that most of what you see quickly becomes all of what you know. Three species of rye grasses you think you’ve seen on a site? Call it by the name of the dominant species that you’ve identified before. Multiple Bromus species invasive in the area? Cheatgrass (Bromus tectorum) and smooth brome (Bromus inermis) are the worst. Hopefully we could both improve our knowledge and record it in a way future staff could learn a little more quickly what it took us weeks to find out.

My co-worker and I begun collecting samples of grasses for pressing into herbarium samples. We carefully dug out roots and attempted to preserve fragile flower-heads. We used Pojar and Mackinnon (Plants of Coastal British Columbia), Hitchcock and Cronquist (Flora of the Pacific Northwest), online resources from pasture managers in the prairies, and iNaturalist. iNaturalist ended up being a great jumping-off resource because it allowed us to quickly scan a list of species photos against our specimens in-hand, and either ID a species immediately or make some conclusions on its family and genus.

Flora of the Pacific Northwest ended up being hard. I started identifying species with the dichotomous keys in Pojar and Mackinnon and Flora because I wanted to be a real biologist. I had success keying out some Elymus (rye), Bromus (brome), and Poa (bluegrass), but got stuck on a handful of species that required 20 or more minutes reading for every abbreviated term Flora introduced in its keys. When Adam came back, he saw me struggling with this handful of species, and referred me to iNaturalist. Within minutes, I was able to scan through species’ photos and identify common invasives photographed and identified on the island. At least two of the header photographs provided for species were incorrect (there is always a face a more experienced biologist makes when you confidently approach them with species or photo in hand and say “it’s this”, and you’re wrong), but I found the service useful enough for a quick ID of common species.

Plant key in Flora of the Pacific Northwest. The illustrations are good looking and useful, and a glossary at the front of the book explains the abbreviated terms.  No photos or descriptions are provided of individual species. Photo credit: Northeast School of Botanical Medicine

 

My favourite grasses book is the unassuming Grasses of Saskatchewan in the Flora of Saskatchewan series. Inside the plain cover of this field-sized book are dichotomous keys to the grass families, keys to genus and species, descriptions of each species, and full-page, full-colour photographs of pressed herbarium species. The photos in this book are the next-best thing to holding the plant in your hand, and helped my co-workers and I get close enough to many species IDs that the keys for genus and species began to make sense.

Grasses of Saskatchewan: Fascicle 4

 

 

 

 

 

 

 

 

 

 

Most of our common species ended up being introduced, and invasive. We had velvet grass, we had sweet-scented vernal grass, we had cheatgrass, we had crested dog-tail grass, we had orchardgrass, and we had common soft-brome. Large portions of the Millard Centre have been disturbed in the past, and the entire Nuts’a’maat Forage Forest is a restored logging site. I expect succession into shrubs and forest will remove some introduced grass species – we have Alaska oniongrass (Melica subulata), California brome (Bromus carinatus) and Roemer’s fescue (Festuca roemeri) growing in forest and meadow sites on the Millard Centre, and these grasses were planted in small numbers in the Forage Forest.

Some time during our grass-ID project I went camping at Dionisio Point on the north end of Galiano Island, and walked around the Garry oak meadows atop the sandstone bluffs of the shorelines. These meadows were covered in bristly dogtail grass. I saw dried shooting start and camas seed-heads poking above so it seemed native flowers were still growing – but the grass layer here was almost entirely represented by this thick-growing exotic species. Many native grasses on the coast are bunchgrasses, forming hummocks and mounds with spaces in-between. A meadow of these species looks very different from the more common sight of a homogenous mat of introduced grasses growing taller than native species and laying down masses of thatch.

Walking back through the Forage Forest, I was able to see that we still have lots of work to do. Most of these species aren’t controllable without disturbing large amounts of soil through burning, mechanical removal, or chemicals, so it’s likely they will persist. At least we can be aware of these, control them in small patches, and plant native grasses as often as possible. Give a patch of bunchgrass a second look the next time you pass, and maybe even say a little “thanks”.

 

 

GCA – Broom Busting

In mid May I started work on Galiano Island. I moved things from Victoria on a Sunday afternoon, got settled into temporary accommodation, and started work on Monday. That morning I met co-workers at the Sturdies Bay office, sat around a coffee table filling out paperwork, ate a quick lunch, and by 1 o’clock I was putting on Carhartts to start our first afternoon’s work – a trip to a scenic-sounding location named Retreat Island to pull broom from a private property and ecological covenant site. Day one set the theme for the next couple weeks – broom busting!

The dry, sunny bluffs and shorelines on the west side of Galiano Island offer excellent habitat for scotch broom. Most of it is accessible by hand; some is pulled by putting on rock-climbing harnesses and rappelling down towards the ocean. Scotch broom fixes nitrogen and changes soil chemistry in meadow-sites used to low-nutrient soils, and physically outcompetes lower grasses and forbs. It grows vigorously along roadsides, in deep and shallow-soil forest clearings, and where trails have opened light and disturbed soil in shadier forests. It would be impossible to get rid of throughout the extent of its introduced range, but volunteer efforts in the Sooke Hills, Victoria, and the Salish Sea have successfully removed it or slowed its growth in protected sites. A few consistent years pulling massive broom and medium broom yield relatively clear sites; consistent repeat visits during following years winnow down the soil seedbank and keep new plants at the edges of sites from advancing.

On day of one work we removed broom from Retreat Island. Day two saw us heading to the Conservancy’s main site, the Millard Learning Centre. On day three we pulled broom from around Laughlin Lake, a small lake and wetland north of the Millard Centre. The rest is a blur, but, within two weeks, we had cleared most of the sites on our list. Our crew numbered five at the start, and seven once two other workers had arrived, plus extra hands from permaculture and education team-members. We pulled two- to three- meter high broom, we pulled two- to three- inch high seedling broom, and we pulled broom that had been cut above the root crown and grown almost impenetrable masses of thick horizontal branches at ground height. Easy hard manual labour proved a great introduction to our team and the sites we’d be working on throughout the summer. We spotted rare plants, chatted longer-term projects for the summer, and spent a lot of time working as a team in the sun and the drenching rain. Within two weeks we completed most of the broom busting, and moved on to setting up the permaculture garden and native-plants nursery for the summer.

Posts from the Summer – Galiano Conservancy Association

This summer I had the opportunity to participate in ecological restoration, outdoor education, and regenerative agriculture with an amazing land conservancy in the Salish Sea – the Galiano Conservancy Association. Hired as a restoration technician, I launched into the summer in May, after graduating UVic in the spring. I joined a team of rockstar individuals and team-members working on everything from rockfish conservation to educational programs delivery to ecological restoration and permaculture gardening. I think we rocked it this summer.

Tentative outline of posts coming up:

May, broom busting, garden projects.

June, forage forest, berry season, grasses.

July, office move, EVENTS, deer monitoring.

August, CISTERN, data completion, Walk-Along. Bonus: anaerobic decomposition.

W̱MÍYEŦEṈ – Mt Work and McKenzie Bight

A Blossoming Time at ÁLEṈENEȻ (Homeland) | Reclaiming W̱SÁNEĆ (Saanich) Place Names on the West Coast of CanadaW̱MÍYEŦEṈ is the area around Mt. Work on the Saanich Peninsula, including McKenzie Bight (1), on the territory of the Tsartlip Nation. The mountain is the first peak to the south of ȽÁWELṈEW̱, or Mt. Newton. To my eye, these mountains form the opposite, high ends of a saddle when seen from afar, with the lowlands of Tod Inlet (SṈITȻEȽ) between them.

I go hiking at W̱MÍYEŦEṈ as often as I can. The mountain is a perfect 45-60 minute walk to the summit, with lots of views opening up in the upper half of the trail. When I ran here the first time it took me about 25 minutes to reach the summit. I hadn’t had enough running at that point, so I ran down the opposite slope to the southern trailhead, and then turned around and ran back the way I came. When I hike I dodder and check out every viewpoint I can.

As the days have grown shorter in the fall, the west slopes of this mountain have remained warm and bright, with lots of large exposed rock to soak up the day’s heat.

The land around W̱MÍYEŦEṈ was important winter hunting grounds for the W̱SÁNEĆ people (1). A translation of this name is “People of the Deer”, and a story tells of how a man was transformed by the creator XÁLS into a deer at this place (2).

 

References

(1) Firstvoices.com, the SENĆOŦEN language homepage

(2) Medium.com, Landscape Magazine, “A Blossoming Time at ÁLEṈENEȻ (Homeland) | Reclaiming W̱SÁNEĆ (Saanich) Place Names on the West Coast of Canada”

View at Medium.com

SENĆOŦEN pronunciation guide  –  http://saanich.montler.net/say/index.htm#IA

SENĆOŦEN place names – https://itservices.cas.unt.edu/~montler/saanich/wordlist/placenames.html

 

 

Lochside Meadow Restoration

I wanted to speak highly of a couple of organizations that are leading a remarkable project in Victoria, and describe a little piece of this project to you.

Peninsula Streams Society, Saanich Native Plants, and Island Pollinator Initiative are developing a restored camas-oak native prairie meadow alongside the Lochside Trail in Saanich. On Saturday, I got to go help them put plants in the soil and seed on the ground.

The urban strip of Mackenzie sits adjacent to some interesting natural areas. To the south is Swan Lake and Christmas Hill Nature Sanctuary. North and west the Blenkinsop Valley stretches up towards Mount Douglas PKOLS. Somewhere in-between is a wide slough amidst agricultural lands, that used to seasonally flood the lower southern valley before ditches for railway, road, and agricultural diversion were put in. Nearby south that slough is a small flat site where many native plants were recently planted, and where, time and tides permitting, a very interesting prairie meadow will take shape.

Not the first place you’d expect for a restoration site.

The restoration site sits underneath BC Hydro lines. A transformer station and public works yard sits across the trail. This site has been unique for its management – BC Hydro owns the land, the CRD leases a right-of-way for the Lochside Trail, and the grass was previously kept mowed by the municipality of Saanich. Now, in addition to these owners and involvers, Saanich Native Plants and Peninsula Streams will tend the land for the next 3 to 5 years, Island Pollinator Collective is taking groups of Reynolds Secondary students on monitoring visits, and it is hoped community-members from the area will be interested in coming out for continued care of the site alongside Saanich Native Plants and Peninsula Streams Society as it grows in.

The Lochside Meadow demonstrates a continued way of collaborating with land-owning agencies and working on margin lands. Think about all the little triangles of grown-in grass alongside buildings, roads, and trails. Projects like this demonstrate a new way of seeing lands like this – the next time I’m riding Lochside Trail I’m going to be looking for a sites at the edges of blackberry hedges in little patches of green near development that now speak greater opportunity. In an earlier meeting on the site, Peninsula Streams shared they’ve been working on the bureaucratic hurdles side of this site for between one-and-a-half and two years to make this project work today. We see the planted meadow and wonder if anyone will be around the next year to support it; for the leading organizations, however, planting represents a continuation of their work on the site, not the start.

So what about the meadows?

We planted lots of aster, goldenrod, buttercup, and camas. A seed mixture including grasses, herbaceous plants and forbs, and great camas was sown. Vernal pools dug into the clay marked sites where a specific assemblage of plants would be started. A similar spot was marked along the work-site’s southern side, where seasonal flooding is expected to be greatest. Different seed mixtures were sown in each of these and the main site. Wire stakes and pink flagging tape marked out these different zones. I listened to conversations about how random we should plant the plants – completely scattered, organized swaths, or in clumps of two or three?

When volunteers arrived at 9:00 am we were greeted by a site already fully prepped. Heavy machinery had been brought in earlier in the week to remove the thick covering of introduced weeds, scrape the site down to the clay, and bring in several inches of new, sterile soil. The difference from when I visited the site two weeks before was astonishing. Margin lands to lands with a plan – the site now looked like a place.

New, dark soil covered the entire site, scattered about with flats of plants, just waiting. A keyhole path and centre area was marked in gravel set with a tent, tools, tables.. as well as timbits and coffee. Vernal pools were marked in lighter clay; piles of rocks were set above the soil in certain places. I remember having a conversation with a leader of this work around 9:45 am. We looked across the plants beginning to be distributed and the people moving around and he thought it seemed ambitious – we might be done by 1:00 or 2:00, not noon. By 11:30 all the plants were dug in and seed was going out. By 12:00 the soil had been raked, volunteers were beginning to depart, tools and plastic pots had been gathered, and the organizers were starting to pack up. Plants were dug in well with roots sheltered properly beneath the soil, seed was sown evenly, and the site looked clean and tidy. Ready for everything we had planted to begin their, far greater, work.

The site will be deer-fenced to protect the starting plants. Winter will add enough water, or perhaps more. Some plants will die, some novel plants will start. It will need to be weeded; patches may need to be seeded again. But it represents a start.

I had another conversation with a woman, leading restoration work elsewhere in the city. She commented that a project she had lead took a year and half to reach this place – they started with cardboard, black plastic, and organic mulch, and waited more than a season for the front-lawn grasses to give up the soil. Heavy machinery sometimes has its place. For her organization’s part, they had started restoration work much earlier in the city, and likely provided inspiration for projects such as this, if not the start of the now-leading organizations themselves. her organization started before Saanich Native Plants existed, before restoration of these prairie meadows on this island had even really begun, and her organization continues to lead a top-notch restoration site today. Makes me think what this next generation of groups and sites could inspire. We’re all still learning from the land, but we have a lot to teach each-other as well.

The site for this restoration couldn’t be better – Swan Lake to the south, Blenkinsop Lake to the north, connected by an active hiking, bicycling, and horseback-riding trail extending from here into the city of Victoria, the rural-wilderness of Sooke, and the farmland of the Saanich Peninsula. Trails have a bad and well-deserved rap for spreading noxious weeds and opening up new sites for future urban growth. Here’s hoping this one can spread native seeds and inspire growth of a slightly different kind. Here’s to finding future sites along the way.