Inaccessible ledges as refuges for the natural vegetation of the high Andes

Abstract

Questions: Have millennia of human land use fundamentally altered the vegetation of a large proportion of the high Andean puna biome, with natural vegetation now restricted to inaccessible areas? Can inaccessible ledges be used as surrogates to infer the potential natural vegetation (PNV) in heavily impacted areas of the puna ecosystem of the high Andes? Is there a difference in plant community composition and diversity between the potential natural puna vegetation, represented by areas inaccessible to grazing and burning, and the anthropogenically disturbed vegetation found on nearby, but accessible, slopes?Location: Abra M alaga Private Conservation Area, Cusco, southern Peruvian Andes.Methods: Four study habitats were chosen that comprised ledges and slopes from within and outside of the conservation area. For each habitat, vegetation composition was recorded using eight to twelve 2 9 2-m 2 plots studied for species cover and abiotic variables.

Human impact on tropical-alpine plant diversity in the northern Andes

“…Distance to the nearest path was the most important land-use variable for plant species composition, suggesting that the impact of human disturbance associated with cattle farming and cropping on floristic patterns is determined by the level of accessibility. This agrees with recent studies that demonstrate that inaccessible habitats can be used to infer the potential natural vegetation in the high Andes (Sylvester et al 2014).…”

An updated checklist and key to the open-panicled species of Poa L. (Poaceae) in Peru including three new species, Poa ramoniana, Poa tayacajaensis, and Poa urubambensis

“…This species was found during a large scale ecological study attempting to reconstruct the potential natural vegetation (PNV) and soils of the high-elevation Puna grasslands (see Heitkamp et al 2014 and Sylvester et al 2014 for pilot studies). In this research, pristine zonal vegetation, only accessible with mountaineering equipment, was compared with surrounding slopes which have been grazed and burnt consistently over millennia (Thompson et al 1988; Chepstow-Lusty et al 1996, 2009; Kuentz et al 2011).…”

A New Species of <I>Moranopteris</I> (Polypodiaceae) from Inaccessible Ledges in the High Andes of Peru

“…Known only from the two collections made at Abra Málaga. This private conservation area is at a confluence between the humid Cordillera Vilcabamba and the dry Cordillera Urubamba and receives updrafts of moist air from the Amazon basin creating a humid climate (see Sylvester et al 2014a for details on the climate). It is the only stand of conserved Polylepis Ruiz & Pav.…”

“…Consistent burning and grazing has resulted in a vegetation formed almost exclusively of plants adapted to these anthropogenic pressures (Laegaard 1992;Becerra 2006), with susceptible species restricted to areas inaccessible to grazing animals and the spread of human-induced ground fires, such as steep cliffs and ledges. The vegetation of these inaccessible areas, some of which can be reached using mountaineering equipment, can be seen as a proxy for the potential natural vegetation of the Puna provided that the vegetation is zonal and not strongly influenced by the surrounding rock faces (Sylvester et al 2014a). Recent surveys of this potential natural Puna vegetation found on inaccessible ledges in the Cusco region, southern Peru, have yielded a number of plant species new to science (Sylvester 2014;Sylvester et al 2014a, unpubl.…”