Runnin’ the Gunni

Two weeks ago Nathan, my co-intern, and I departed Denver in a mid-May snow storm which had socked in over the southern Rockies and turned mid- May into what seemed more like mid-winter. Such is the weather on the crest of the continent. We were headed to the western slope to run the Gunnison to complete cactus surveys. The Gunnison is one of the Colorado’s principle upper tributaries which drains the western aspects of the Continual divide as it runs through the Sawatch and San Juan mountains. Despite the snow rapidly accumulating outside my house in Denver the previous evening, I shoved board shorts, sandals, and the typical warm weather river gear into my dry bag feeling like I was packing more for a tropical get-away than for the wintery wet conditions outside.
The storm wore on the next day as we passed through South Park, down into the Arkansas River valley, and over the continental divide at Monarch Pass. Tomichi Creek and the town of Gunnison were encased in a wintery blanket of white. We continued westward into the evening passed Blue Mesa finally pausing at the rim of the Black Canyon to rest for the night. It was late and we needed to be up early, I hesitated before setting up my tent but finally conceded considering the conditions. It snowed late into the night accumulating lightly on the rain fly of my tent every so often cascading off in miniature avalanches. The temperature dipped low but I stayed warm insulated inside my goose down bag.

The following morning the snow had stopped but a heavy fog still shrouded the Black Canyon. As we drove off the rim toward Montrose the red rock country lay in the distance basking in the early morning sun; leaving us hopeful that the weather had finally taken a turn for the better. We met Brandee and Ken at the Uncompahgre Field Office in Montrose to assemble the gear and meet with river rangers Blaire, Ryan, and Rooster the head honcho. We were going on a cactus hunt.

The BLM on the western slope has been caught up in a debate over a small barrel cactus. Sclerocactus glaucus has consumed most of my time at the state office for the past several months. Earlier this year I conducted a literature review and compiled a status report for the species with the ultimate goal of getting a delisting package and petition drafted this coming winter. While the cactus most certainly has a limited range of distribution; being that it is endemic to several counties on Colorado’s western slope, it is certainly more abundant than USFWS believes it to be. I recently received an update to the Element Global Rank documented by the Colorado Natural Heritage Program estimating a total global metapopulation size of 25,000 individuals. Having been working with the cactus for the past three months it was clear that this was likely a low-ball estimate.

Unlike many other rare and endemic species S. glaucus doesn’t appear to be a specialist. In fact, within its confined range we’ve found it occupying a wide variety of habitat some of which is very intact and other areas which would be considered marginal by the most generous assessment. We’ve found it occupying sites with highly developed cryptogrammic soils, on selenium shale badlands, areas of hardscrabble as hard packed and scabby as concrete, and in areas nuked by grazing where you literally have to peel back the cheat grass to find the plants. In general though, S. glaucus doesn’t venture very far from the alluvial river terraces of the Colorado and Gunnison Rivers in the upper reaches of their basins. A broad swath of potential habitat exists in a rather remote region which spans the Dominguez-Escalante National Conservation Area and the Dominguez Canyon Wilderness and is only reasonably accessible by floating the river.

As we drove to the put-in north of Delta, low clouds and a fresh layer of snow clung to the broad flanks of the Grand Mesa, but by the time we shove off mid-morning the temperature had climbed into the mid-sixties with cobalt blue skies and a slight breeze and only promised to improve. The weather in the high desert canyons of the western slope is capricious by nature. During the short spring season you could experience a variety of weather ranging from rain and snow to temperatures in the upper eighties. The river was cappuccino muddy and running reasonably high at 3,500cfs. Rooster informed me that with the monumental snowpack still clinging to the divide and the coming warm temperatures that in a few week’s time the river would be ripping at at least twice its current volume. The stretch we were running though was fairly tame and lazy so it wasn’t difficult to sit back, relax, and watch the canyons unfold around each meander.
We were targeting areas on the rivers west bank which is encompassed by the wilderness area; the goal being if we can locate significant populations which are already within a protected area that our pitch for delisting will be strengthened. Despite having nine people and the better part of three days the amount of potential habitat flanking river left was remarkable, stretching nearly the entire 26 miles between Escalante Canyon and our take out a Whitewater just before Grand Junction. We focus on areas surrounding establish river-rat campsites fanning out along alluvial slopes and ledges. It isn’t long before were into the cactus. We assess areas quickly, pin flagging individuals to keep a running count, mapping polygons, and moving on downriver – a process we keep up for three days. The river rangers aren’t the only ones astounded by the amount of cactus we were finding. You could barely walk a few feet in any direction without bumping into it clustered cactus bunches crouching squat in the grass and shrubbery. On one afternoon we effectively counted close to 2,000 individuals in a five acre area.

By the time we reached the take-out at Whitewater we were nearly cactus’d out and feeling pretty good about ourselves. After three days of surveys in only a portion of the potential habitat which flanks the river through the canyons, we successfully located 6,000 previously undocumented individual cacti, or nearly 20% of the previously believed global population. With another few tours in the boats it is very conceivable we could locate an additional 25,000 individuals. It remains to be seen what the fate of the cactus will be. But for now it feels good to know that hard work and persistence pays off.
Until next time from the Front Range,

Phil Krening
Colorado State Office – BLM
Lakewood, CO