A raucous flock of Chestnut-Fronted Macaws (Ara severus) signals both the commencement and closure of each day at Wildsumaco Wildlife Sanctuary (WWS). The birds stridently announce their passage down the side of Ecuador’s Volcán Sumaco towards their foraging grounds each morning, and every evening they return up the mountainside to roost, a chaos of caws and cackles.
The macaws may be one of the most conspicuous residents of WWS, but the flock is only a colorful drop in the bucket relative to the vast diversity of species that inhabits this mountainside. Sumaco bears the distinction of being the easternmost of Ecuador’s Andean peaks, making it one of the few mountains with slopes leading straight down into the Amazon basin. Essentially, it is a forested conduit linking the surreal landscapes of the Andean páramo and the bejeweled richness of the lowland rainforest.
The view from the deck of the WWS lodge showcases a large part of Ecuador’s share of the Andean mountain chain, from the vast snowy peaks of Antisana to the restless smoking and belching of Tungurahua. The frequent rain showers are always followed by a surreal vista of the mists settling over the valleys to either side of Sumaco’s southern slope.
Given enough time, patience, and good old-fashioned luck, you might encounter any number of wonders within Sumaco’s foothills. Potential sightings include the endangered white-bellied spider monkey (Ateles belzebuth), the tamandua (Tamandua tetradactyla) - a small blond anteater with a preference for spending time in trees - two different woodpeckers from the same genus (Campephilus) as America’s lamented Ivory-Bill, a singing bamboo rat, or any number of species of clear-winged butterflies and delicate glass frogs.
It sometimes seems as though many of the animals at Sumaco are supersized: earthworms and caecilians—legless amphibians—that grow to nearly 2 meters in length, land snails as long as a man’s foot, and a diurnal eight-pound rodent, the black agouti (Dasyprocta fulginosa). At the same time, there are innumerable miniature species at hand: petite marsupial mouse opossums, dozens of hummingbirds, a squirrel sized primate - the Napo tamarin (Saguinus graellsi) - and the diminutive margay (Leopardus wiedii), a tropical felid that is roughly the size of a house cat...depending upon how pampered your housecat is.
The local bird species list at Sumaco currently bears 487 species, and that tally is inching higher and higher all the time. If you venture out at night and shine a light into the canopy, you might see the lantern-like eyes of a kinkajou beaming back at you. The mud rimming the forest paths often showcases a variety of paw prints, ranging from the substantial pugmark of the puma to the dainty, nearly imperceptible toe impressions of the mouse opossum.
Having been lucky enough to have the opportunity to conduct my Master’s thesis research at Sumaco, I have gained a deeper appreciation for the site with each and every field excursion over the past 20 months. When your "lab" is framed with bromeliads and buzzes with the wingbeats of hummingbirds and the chatter of toucans, it is sometimes tough to remember that what you’re doing is actually work.
I usually arrive at Sumaco after an abrupt transition from the muggy coast of North Carolina to the chilly heights of Quito. After losing all thermal equilibrium during that journey, Sumaco is a mild, verdant relief. WWS is situated merely 45 miles south of the equator, yet the temperature hovers in the low 70’s every day of the year. The sanctuary’s position at a middle elevation—about 1400 meters high on the side of Volcán Sumaco, which reaches a peak of 3800 meters—results in both a moderate climate and a stunning degree of biodiversity.
The site occupies an elevational zone that covers both the upper elevational limit for many lowland Amazonian species and the lower elevational limit for various upland Andean species. This creates a "sweet spot" with the potential for rare and unique assemblages—combinations of species that only co-occur within a narrow band of elevation. In addition, WWS is neighbor to Sumaco National Park, creating a potential "overflow zone" for animal that live within the protected boundaries of the reserve.
My research at Sumaco has opened my eyes to the incredible number and diversity of species packed into these tropical forests: we have documented over a third of the terrestrial carnivore species that occur in the entire country of Ecuador within WWS—that is 37% of the country’s carnivore diversity in an area just one quarter as large as that covered by the Atlanta airport.
This leads to the question: if all of these species are packed into Sumaco’s forests together, how do they manage to co-exist? A driving goal of my thesis research was to investigate and understand niche partitioning strategies and potential intraguild interactions between Sumaco’s carnivores. In addition to examining guild dynamics, I chose to focus on the margay, which is little-known and declining throughout most of its range in Central and South America.
When authorities took measures to stem the slaughter of ocelots—whose coats are in high demand on the black market for wildlife parts—many poachers turned to the margays as an alternative source of spotted pelts, and soon their populations became depleted as well. Smaller and more elusive than ocelots, little is known about many aspects of the margay’s behavior, diet, and natural history in general. Part of my study focused on elucidating habitat preferences of this species, in addition to assessing the impacts of domestic dogs on margay activity patterns.
All of my sampling was conducted noninvasively, using remote cameras equipped with both motion and infrared sensors. The cameras also use an infrared flash, to avoid startling the animals and potentially altering their behavior and movement patterns. The margays’ spotted coats each bear a unique pattern, just like a fingerprint. This allows us to use the game camera photos to identify individuals, and to estimate how many total margays inhabit a given area.
For some reason, Sumaco appears to be a hotbed of margay activity. The camera trapping success with this species was much higher than expected, and we documented interesting behaviors, such as tree-marking, a distinct pair of margays that appeared to associate with one another repeatedly over the course of a month, and extensive use of the ground by a species that is thought to prefer spending time in the canopy.
The University of North Carolina-Wilmington (my current institution), in collaboration with Francis Marion University, has recently established a research outpost at Sumaco, an accomplishment of the joint vision and efforts of Dr. Brian Arbogast of UNCW and Prof. Travis Knowles of FMU. Jonas Nilsson and Jim and Bonnie Olsen, the owners of WWS, have been essential in facilitating the undertaking. After years of planning and jumping through numerous logistical hoops, the construction of the brand-new Wildsumaco Biological Station is set to be completed later this year.
With the opening of the new field station, exciting new opportunities will be available to work on teasing out the ecological intricacies of Sumaco’s forested slopes. Even two and a half years after the initiation of camera trapping at the site, the list of resident mammals continues to grow, with additional species periodically being detected for the first time.
The task of documenting other vertebrates, invertebrates, and plants has barely begun, and future research within the adjacent Sumaco National Park will lead to a better understanding of elevational diversity patterns in the eastern Andes—a critical issue at a time when climate change threatens to shift current climate envelopes upwards, making mountain peaks potential arks of biodiversity struggling to persist despite rising temperatures.
Sumaco is unquestionably one of Ecuador’s jewels, and the surface of its biodiversity has barely been scratched. The forests that blanket these slopes are sure to yield further insights and discoveries in the future, contributing both to our professional understanding of tropical ecology and to our natural sense of awe at the natural world.
Previously by Anne-Marie Hodge at Scientific American: