In two consecutive years of my PhD, I spent the weekend before Thanksgiving 300 miles away from my family, fighting with temperature loggers in a National Park. This was not so much “opting outside” as desperately trying to install soil probes in raised beds that were basically garden-sized popsicles. But looking back, I perversely treasure those November trips to Maine and the chance to spend a quiet day on the mountain before the bell lap on the fall semester rushed through December. These last-minute-get-the-equipment-in-the-ground-before-the-snow-falls trips occurred in the years before REI created the #OptOutside hashtag, and on the wrong side of Thanksgiving anyway, since we are corporately encouraged #OptOutside instead of shopping on Black Friday. Regardless, this is the image in my head when I think about #OptOutside: standing alone below the summit of Cadillac Mountain under a grey Maine sky, snow flurries dotting my datasheet as the bare branches of the birches and maples and shadbush below fade to purple against the granite.
It is rare to have Cadillac to yourself. Acadia is crawling with people opting outside year round: hiking, rock climbing, cross country skiing. My research on plant communities was recreation-adjacent — I monitored phenology on hiking trails — but this fall I read four interesting papers exploring recreation ecology itself. Recreation ecology is the study of human impacts on landscapes where we play; this subfield is decades old with some foundational books (including Wildlife and recreationists: coexistence through management and research and Wildland recreation: ecology and management), but it is often neglected when we ecologists think about conservation (our prevailing views on conservation historically exclude people) or the top 100 papers in our field. Matthew Klingle wrote an excellent essay examining #OptOutside from the cultural and consumerism perspectives, critiquing the socio-economic assumptions about who gets to opt outside and where they get the gear they are hauling into the woods and artfully arranging for their instagrams. I am writing this post as the ecological companion piece: what are the impacts of our recreational activities on the plant and animal communities we hope to conserve? In honor of opt outside day — or for folks who are opting to read about the outside world — here are my top four 2017 papers on recreational ecology.
Impacts of rock climbing on plant communities.
Research on the ecological impacts of rock climbing received some press this year from the Sierra Club’s magazine. In a short piece, Diana Crow outlined recent findings that indicate climbing routes support less plant cover and lower biodiversity than unclimbed cliffs. Among these studies is a PLoS ONE paper from Juan Lorite on the Mediterranean limestone cliffs. Dr. Lorite told me that he did not approach the study of cliff flora from the perspective of a rock climber — “I have tried [climbing] but I would rather prefer to keep my feet staying on the ground” — however, “two students (Fabio Serrano and Adrian Lorenzo co-authors of this work) contacted me to do their master’s thesis and end-of-degree project respectively, on the impact of climbing rock over plants. Both were biologists and also climbers and were worried about the impact of this activity.” Lorite and his colleagues paired unclimbed cliff transects with climbed transects across three levels of climbing use and used photographs to compare the plant cover and biodiversity on these cliffs.
Laura Boggess and co-authors used a similar methodology in Big South Fork National River and Recreation Area, Tennessee to survey the cliff flora of sandstone cliffs. Here, they carried 1m2 quadrats into the field and visually estimated percent cover as they rappelled down, collecting plants, lichens, and mosses from either side of the vertical transect. Boggess, a mountaineer, got started climbing as a master’s student when the grant for this research was funded. She stressed the importance of studying the impacts of climbing from inside the climbing community: “it’s nice to have participation in the activity when you study its impacts, it improves communication across groups.” While the Sierra Club article generalizes that “few ecologists have enough climbing experience to do the work”, Boggess points out that the field work is not technically rock climbing up, it’s rappelling down. Often the hardest part was actually bushwalking to the tops of the cliffs. In addition, the Boggess’ coauthor, Gary L Walker, and his lab at Appalachian State, have been surveying cliff flora and writing reports for many years using standardized methods; they don’t often publish peer-reviewed literature and they were not included in the Sierra Club article.
The “cliff” notes comparison of Lorite and Boggess’ results: climbed routes supported significantly less plant cover and diversity in the Mediterranean, but there was no difference in climbed and unclimbed routes in Big South Fork. Looking deeper, Lorite found that the more heavily used and overcrowded climbing routes were the most impacted; the more specialized (and less crowded) routes experienced relatively little damage. Boggess points out that Big South Fork generally receives low levels of climbing traffic — it’s routes are remote and undeveloped and it is located between two nationally recognized climbing areas in the Obed River Gorge and Red River Gorge. But, rock climbing is gaining in popularity nearly everywhere, including Big South Fork, and Boggess told me that anecdotally there do seem to be more climbers in Big South Fork since she conducted her fieldwork. In fact, part of her analysis included a creating a spatial model of the cliffs across the park: “we added a simple layer of climbing attractiveness to further specify which cliffs climbers may prefer to develop.” One of the critiques of rock climbing studies in general is an oft-repeated maxim that climbers self-select routes with lower diversity because it’s easier to climb on bare rock. If this is the case, then comparing climbed routes to unclimbed routes is a biased methodology: the unclimbed routes aren’t a control and monitoring ideally should be before-after control-impact. Here, Boggess might have just published the ‘before’: her work identifies cliffs that are likely to become climbing routes and her results are a prime candidate for re-surveying to assess the impacts of increased climbing pressure in the future. Additionally, Boggess is very clear that the face of the cliff is not her main concern: “it hurts my heart to see trampled moss mats at the top of a cliff.” Her research found interesting and sensitive vegetation along the cliff tops, and she urges climbers to used fixed anchors instead of “topping out” and climbing over the edge of cliffs. Lorite also has advice for climbers hoping to minimize their impacts. “Some common practices are very harmful and should be abandoned, for example the conditioning process for a new route establishment usually consist of removing all the plants and to brush the rock surface removing all the mosses and lichens attached to the rock. Surprisingly this activity is called in the jargon as ‘gardening’ causing a high impact on plant community.”
Cross country skiing and meadow vegetation
What about our recreation during the plants’ dormant season? A research group from Germany has a paper in press in Basic and Applied Ecology that explores the ecological impacts of cross country skiing on meadow vegetation. Manuel Steinbauer and colleagues looked at cross country ski tracks in the Fichtelgebirge, in northeast Bavaria; since floodlights were installed in 1979 for night skiing, the heavy grooming machinery has covered the same 84 km of tracks for over 30 years. I was unable to arrange an interview with Dr. Steinbauer or his coauthors, but I talked to Chelsea Little, a PhD candidate at the University of Zurich in Switzerland and editor-at-large for FasterSkier.com about this paper. Chelsea and I both read this paper last month when it was first available online as an accepted manuscript; we were intrigued by the paper’s bold title “Positive sport-biosphere interactions? − Cross-country skiing delays spring phenology of meadow vegetation.” First, we recognized that the conditions at the study site were somewhat unique in the heterogeneous world of cross country ski tracks. Chelsea writes:
I think one thing to think about is that this doesn’t necessarily mean that there is overall more maintenance of these trails than the non-lighted trails – the lighting is somewhat independent of the degree of other management. Also, they aren’t, like, football stadium lights. They are fairly weak in a lot of places. It does mean that light pollution is a relevant question though! And also, having skiers moving around when it is dark probably has very different effects on wildlife, for example, than places where skiers are only out during the day…
I guess that this brings up one question I had about the study. There is a huge gradient in terms of how intensively ski trails are managed. Some very minimally, and they are only skied when there’s enough snow to cover everything. On the other hand, I worked at a place in Vermont where we often scraped and graded the trails during the summer, used crowbars to pry out rocks, and reseeded the trails with grass, all with the purpose of making it possible to ski even when there’s just a little bit of snow. Given the current climate, more and more cross-country ski areas are also investing in snowmaking. This will result in bigger and bigger mismatches in growing season length between the ski trails and surrounding areas, and also even bigger differences in water and soil moisture conditions.
Steinbauer and his colleagues collected an incredible array of data on the vegetation and the conditions in plots on and off the tracks (similar to the climbed/unclimbed transects): flowering phenology, above-ground biomass, species composition, snow cover, soil frost, soil moisture, soil density, daily radiation, and detailed interviews with the landowners! Ultimately, they found no significant difference in plant species richness or biomass production between the ski trails and the off-trail plots. However, flowering phenology was delayed by almost two days on the ski track. They conclude that on these trails — which are lit and groomed but receive no artificial snow — the impact of ski trails on the meadow vegetation is minimal, and may be seen as a “positive” because they add environmental heterogeneity. Both Chelsea and I were wary of this broad conclusion. From my background in plant phenology, I wanted to know more about this delayed flowering: what were the pollinators doing? Was there gene flow between the on- and off-trail plant populations? Chelsea took a hard look at environmental heterogeneity:
It seemed rare to me that creating environmental heterogeneity where there was none before would be considered a positive outcome. I totally understand that heterogeneity can be great in promoting metacommunity stability, for example. In my mind, however, when trying to apply this in a conservation setting, it would be more about trying to stem the homogenization of habitats that comes with development, large-scale agriculture, or some managed forestry…But in this case of this paper, it seemed like they are talking about doing the opposite: taking an intact-ish piece of habitat (although it is a set of meadows which are mowed by the landowners, so not exactly pristine), and making it more heterogeneous.
Ultimately, the ecological impacts of ski trails depend on the local management decisions and the vegetation is not the only aspect of the environment that may be affected. Last summer Chelsea wrote at piece for FasterSkier.com about the impacts of skiing on wildlife. She reflects: “It was interesting to see the reaction from skiers – this is a demographic that in general is fairly environmentally conscious (after all, they spend a lot of time outdoors), but I would say that overall they did not seem impressed that we should change our trail design/layout for the benefit of wildlife, as it is felt that cross-country skiing is a very low-impact activity compared to many others (i.e. snowmobiling, downhill skiing). But I hope that people will start being more thoughtful about how we fragment the forest even with these seemingly low-impact trails, and leave some big chunks of habitat undisturbed.”
Wildland recreation disturbance at broader scales: hiking & wildlife
Finally, the cover picture of the November issue of Frontiers in Ecology and the Environment features a line of photographers angling for a shot of a bison. Inside, Kevin Gutzwiller and coauthors explore the impacts of wildland recreation (like hiking and wildlife photography) at a broad scales — think entire parks instead of individual cliff faces — through GIS and statistical approaches. I talked to Gutzwiller and his coauthor Ashley D’Antonio about this paper and the field of recreation ecology in general. Gutzwiller literally wrote the book (Wildlife and recreationists) on recreation impacts on wildlife. When comparing impacts on plants and animals, he says it’s “fundamentally an issue of movement. Plants ten feet off of a trail may be safe from trampling. Wildlife can move but that doesn’t mean they are less susceptible. It’s harder to link the impacts to disturbance.” D’Antonio echoed: “wildlife impacts are hard to measure at the population level: if you flush a bird, how does that affect the bird populations? A lot of recreation ecology studies are very site specific…this is a smaller scale than that at which wildlife actually function and live in the ecosystem. This is a major constraint to studying wildlife impacts.” Their paper aims to help conservation managers scale up and look at recreation as another layer on the landscape. They both stressed that the field of recreation ecology wants to get people outside: they want their research to provide opportunities to enjoy the landscape, while minimizing impacts. Here, they hope their conceptual paper can get managers thinking about what they already do — using GPS techniques to see how visitors interact with resources — and adding two statistical approaches to quantify disturbances and model them across landscapes.
I asked Gutzwiller and D’Antonio about the intersection of their recreation ecology research and their personal outdoor recreation hobbies. Gutzwiller is an all-around outdoorsman who enjoys cross country skiing, snowshoeing, hiking, fly fishing, and hunting. “Getting out into remote wild areas is what I live for — I’d love to be there almost all of the time. You get insights out there you can’t get from looking at walls.” He says that knowing the literature, “knowing how subtle disturbances can affect animals influences how I recreate.” D’Antonio, an avid hiker — “it’s pretty much what I study too, mostly-foot-based recreation, boots on the ground type of impact” — worries that she’s becoming an annoying hiking companion between pointing out the social trails and stopping for photographs of signage instead of views. She says that though it can feel like work “because I can’t turn off seeing the impacts,” work and play can overlap a lot in recreation ecology. Getting outside is “an opportunity to clear your head, do the deep work, and think creatively.” Throughout my interviews for this post scientists told me this repeatedly: getting outside improved their work. The #OutdoorsyScientist hashtag in September 2017 made it pretty clear that many scientists on twitter — from the recreation ecologists to the lab-bound biologists and indoor modelers — find restoration, renewed energy, and stress release in the great outdoors. Those scientists who have dug into the research on recreation impacts, or who are actively engaged in the studies themselves, seem universally conscientious of their footprints, ski trails, and climbing routes. I hope their work and their thoughtfulness ripple out across the outdoor communities as we opt outside today and in the future.
Finally, I want to share Gutzwiller’s enthusiasm for working on this 2017 wildland recreation paper: “I had a blast working with Ashley [D’Antonio] and Chris [Monz]! They’re fabulous. I wish they worked down the hall from me!” This conversation made my heart grow three sizes a la the grinch. My holiday wish is that we all end up with coauthors who gush this way about us.
Gutzwiller, Kevin J, Ashely L D’Antonio, and Christopher A Monz. 2017. Wildland recreation disturbance: broad-scale spatial analysis and management. Frontiers in Ecology and the Environment. 15(9): 517-524, doi: 10.1002/fee.1631
Boggess, Laura M, Gary L Walker, and Michael D Madritch. 2017. Cliff flora of the Big South Fork National River and Recreation Area. Natural Areas. 37(2):200-211.
Lorite, Juan, Fabio Serrano, Adrian Lorenzo, Eva M. Cañadas, Miguel Ballesteros, and Julio Peñas. 2017. Rock climbing alters plant species composition, cover, and richness in Mediterranean limestone cliffs. PLoS ONE. 12(8) https://doi.org/10.1371/ journal.pone.0182414
Steinbauer, M.J., Kreyling, J., Stöhr, C. and Audorff, V., 2017. Positive sport-biosphere interactions?− Cross-country skiing delays spring phenology of meadow vegetation. Basic and Applied Ecology.