• A new camera trap study, the results of which were published in the journal Oryx last week, seeks to fill in the gaps in our knowledge of the Cerros del Sira’s mammalian inhabitants.
  • An international team of scientists from Peru and the UK led by Ruthmery Pillco Huarcaya, a biologist at Peru’s National University of Cusco, deployed 45 camera traps from 2015 to 2016 in the Sira Communal Reserve, part of the Oxapampa-Asháninka-Yánesha Biosphere Reserve.
  • Aside from revealing the distribution of and threats to the Cerros del Sira’s mammal community, the results of the camera trap survey led to a number of other insights.

Due to their remoteness, the high-altitude tropical forests of the Cerros del Sira, an isolated mountain range in the eastern Andes of central Peru, are known to harbor a diverse array of rare and endemic species like the Sira currasow, a critically endangered bird that can be found nowhere else on Earth.

An expedition to the Cerros del Sira resulted in the first-ever camera trap footage of the Sira currasow (Pauxi koepckeae) being made available to the public in 2015. That camera trap survey also discovered the presence of Andean spectacled bears (Tremarctos ornatus) in the remote mountain range — some 100 kilometers (or 62 miles) distant from any of the bear’s previously known habitat. This was an important discovery because, while the Cerros del Sira are known to harbor a unique and diverse array of Andean and Amazonian birds, amphibians, and plants, the mammal species who call the mountain chain’s tropical forests home are still poorly known and relatively under-studied.

A new camera trap study, the results of which were published in the journal Oryx last week, seeks to fill in the gaps in our knowledge of the Cerros del Sira’s mammalian inhabitants.

An international team of scientists from Peru and the UK led by Ruthmery Pillco Huarcaya, a biologist at Peru’s National University of Cusco, deployed 45 camera traps from 2015 to 2016 in the Sira Communal Reserve, part of the Oxapampa-Asháninka-Yánesha Biosphere Reserve. The largest community reserve in Peru, the Sira Communal Reserve encompasses the Cerros del Sira Mountains and a surrounding buffer zone that includes indigenous Ashaninka, Asheninka, Shipibo-Conibo, and Yanesha groups as well as rural communities of Andean migrants. The camera traps, placed at regular intervals between elevations of 800 and 1,920 meters (about 2,625 to 6,300 feet) from 2015 to 2016, detected 34 large and medium-sized mammal species in the Cerros del Sira.

“The distribution of species across the elevational bands indicates that diversity was highest at 1,000–1,250 [meters], with the highest observed species richness at 1,250 [meters],” Pillco Huarcaya and team write in the study. “Only five species were detected at >1,400 [meters]: the oncilla Leopardus tigrinus, the spectacled bear, the long-tailed weasel Mustela frenata, the Andean white-eared opossum Didelphis pernigra, and the pacarana Dinomys branickii.”

It appears that this mammalian community, like the critically endangered Sira currasow, is facing numerous threats to its continued existence: eight of the mammal species the researchers detected are listed as threatened on the IUCN Red List. (There is not enough data to assess the conservation status of three other mammal species the researchers found, and one additional species has yet to be assessed.)

“There is increasing awareness of the threats to high-elevation species but studying them is often hindered by rugged terrain,” Pillco Huarcaya said in a statement. That ruggedness was expected to deter hunting in the Sira Communal Reserve, but the camera traps captured illegal hunting activity even at elevations as high as 1,400 meters within the protected area. Through informal interviews with members of the communities living in the reserve’s buffer zone, the researchers learned that key bushmeat species like the Peruvian woolly monkey, the black-faced spider monkey, and the white-lipped peccary have already disappeared from nearby lowland areas, driving hunters further up the Andean slopes and into the core of the protected area.

Illegal logging is also impacting the Sira Communal Reserve and potentially putting its biodiversity in jeopardy. Pillco Huarcaya and team say they witnessed illegal logging inside the reserve’s core area firsthand in 2016, and an analysis of satellite data by the Monitoring the Andean Amazon Project (MAAP) that same year showed forests had been cleared in the northern reaches of the core zone for crops, cattle pasture, and gold mining.

Aside from revealing the distribution of and threats to the Cerros del Sira’s mammal community, the results of the camera trap survey led to a number of other insights. Pillco Huarcaya and team say that, to the best of their knowledge, their camera traps are the first to capture spectacled bears at the same location as jaguars — the two species are the largest land predators in all of South America, and they were both captured by the highest camera the team deployed, at an elevation of 1,920 meters. It was previously believed that the elevation ranges of the two species did not coincide on any single mountainside in Peru and Bolivia, only overlapping at an elevation of about 900 meters throughout the Cordillera Oriental branch of the Colombian Andes.

The detection of the threatened oncilla, a small cat species that is one of the least known Neotropical mammals, was also notable, the researchers said, because the Cerros del Sira are about 60 kilometers west of the oncilla’s known range, based on the current IUCN distribution map for the species.

“The Cerros del Sira is exceptionally diverse, with a unique assemblage of species comprising typical lowland Amazonian species as well as high-elevation species,” Andrew Whitworth, a researcher at the University of Glasgow and co-author of the study, said in a statement. Whitworth led the team that captured the first-ever video footage of the Sira Currasow four years ago.

“The detection of large-bodied species that require large intact habitats include the lowland tapir and the giant anteater, suggesting a high degree of ecological integrity within the core Sira Reserve, while the presence of many small, rare and cryptic species, including the margay, the short-eared dog and the pacarana, further underlines the importance of the reserve in sustaining species of conservation significance.”

Increasing human pressures on the high-elevation habitats of the Cerros del Sira combined with range shifts driven by climatic changes could lead to “catastrophic” species loss, the researchers write in the study: “Although climatic changes are not of dramatic consequence for species residing in low-lying well-connected habitat, tropical species in isolated ranges, such as the Cerros del Sira, will have no suitable habitat to shift to, and could be outcompeted by low-elevation species moving to higher altitudes.”

“Fragmentation and isolation could be detrimental to the Cerros del Sira,” Pillco Huarcayaya added. “Surrounding areas must retain sufficient integrity and connectivity between key protected areas of the Oxapampa-Asháninka-Yánesha Biosphere Reserve to facilitate species migration and gene flow for viable populations of the incredible species we detected to persist, especially those larger-bodied ones.”

Jaguar (Panthera onca). Photo Credit: Exploration Sira.


South American tapir (Tapirus terrestris). Photo Credit: Exploration Sira.
Cougar (Puma concolor). Photo Credit: Exploration Sira.
Giant anteater (Myrmecophaga tridactyla). Photo Credit: Exploration Sira.
Ocelot (Leopardus pardalis). Photo Credit: Exploration Sira.
The tayra (Eira barbara), an omnivorous animal from the weasel family. Photo Credit: Exploration Sira.
Andean spectacled bear (Tremarctos ornatus). Photo Credit: Exploration Sira.

CITATIONS

• Huarcaya, R. P., Beirne, C., Rojas, S. J. S., & Whitworth, A. Camera trapping reveals a diverse and unique high-elevation mammal community under threat. Oryx, 1-8. doi:10.1017/S0030605318001096

• Novoa, S., Finer, M., & Snelgrove, C. (2016). Threats to Peru’s El Sira Communal Reserve. MAAP: 45.

Follow Mike Gaworecki on Twitter: @mikeg2001

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