The tropical glaciers in the Bolivian Andes Mountains are small and respond quickly to changes in their climate. They are also a major source of freshwater year-round for nearby communities. Monitoring the glacial changes taking place in these glaciers has become increasingly important as they have been retreating over the past century. These glaciers are remote and the terrain treacherous making it potentially dangerous to gather data through field work. For this reason and because of advances in remote sensing technologies the use of satellite images has become the primary means to study these tropical glaciers in detail. This research study focuses on the Cordillera Apolobamba range located on the Peruvian-Bolivian border. It is an example of the methodology applied to assess the area covered by glaciers in this and other regions around the world. Using Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) images from 1985 to 2010, as well as the Glacier Inventory of Bolivia, the glacier extents of the Apolobamba are mapped. From 1975 to 2010 the portion of the range located within Bolivia's border lost 110.76 km^2 of surface ice lowering its total area from 240.36 km^2 to 129.60 km2, a 46.08% reduction. From the 1985 to 2010 the entire Apolobamba range lost 102.72 km^2 of ice lowering its total area from 261.07 km^2 to 158.35 km^2, a 39.35% reduction. An analysis of atmospheric conditions was conducted at the 500 hPa level for various climate variables using NCEP/NCAR reanalysis data. Between time period one (1975-1986) and two (1987-1995) the climate variables exhibiting a statistically significant change are air temperature with an increase of .165 degrees C and geopotential height with an increase of 2.967 m. Between time period two and three (1996-2005) the climate variables exhibiting a statistically significant change are freezing level with a 50.017 m increase, precipitation with an 60.604 mm/month decrease and wind velocity with an increase of .373 m/sec. According to the analysis conducted using the Oceanic Nino Index, the monthly sea surface temperatures exhibit no statistically significant change from 1975-2005.

Les Leco du nord de La Paz étaient considérés disparus à la fin du XXe siècle, pourtant en 1997, deux groupes resurgissent séparément pour compter au total 9006 Leco en 2013.Si la résurgence ne fut pas conflictuelle à Guanay où se parlait une langue leca il y a 50 ans, elle fut violente à Apolo, où les Leco partagent langue, culture et parenté avec les paysans quechua voisins qui contestent à la fois leur droit à un territoire et leur condition de « vrais » Indiens.Afin de dépasser les essentialismes, la thèse tente de comprendre ces résurgences à partir de l’étude ethnohistorique de la région et de saisir les brassages hétéroclites d’où sont issus les Apoleños (indigènes Leco et paysans).Véritable nœud entre hautes et basses terres, Apolobamba a reçu très tôt des apports andins (puquina, aymara et quechua). Ses habitants, les Chuncho des Incas puis des Espagnols, présentent tous des traits linguistiques et socioculturels hybrides. La diversité ethnique se réduit dans les missions franciscaines du XVIIIe siècle, instaurant la frontière ethnolinguistique du Tuichi entre un sud plus andin et les « sauvages » du nord. Le libéralisme de la période républicaine et la construction identitaire nationale amenuisent encore la diversité régionale et accélèrent l’« andinisation ». De ces brassages émergent les Apolistas puis les Apoleños ; des identités toponymiques plus qu’ethniques. La renaissance des Leco s’inscrit dans un panorama national et international favorable, mais une langue leco se parlait encore il y a deux à trois générations sur les bords du Mapiri. Se pose le problème des transformations des sociétés et de leur continuité : métissages, acculturation, ou bien ethnogenèse, camouflage et résistance ? / The Leco from North of La Paz were considered to have disappeared by the end of the XXth century ; however in 1997, two groups of Leco re-emerged independently from each other, one in Larecaja and one in Apolo. In the former the claim was less violent than in the latter, where Quechua peasants share language, culture and kinship, and refuse to recognize the land rights and the identity of their “Indigenous Leco” neighbours.The thesis aims to understand ethnohistorically both resurgences, and tries to go beyond essentialism to understand the heterogeneous melting pot from where the Apoleños come.Apolobamba, because it connects highlands and lowlands, received Andean influences (puquina, aymara and quechua) early on. Its inhabitants, the Chuncho of the Incas then the Spaniards, show hybrid ethnolinguistic and socio-cultural features. The ethnic diversity was being reduced in the 18th century Franciscan Missions, where the ethnolinguistic border between an Andean South and the “savages” of the North was drawn at the Tuichi river. The liberal Republican period, with the construction of a national identity, once again shrunk regional diversity and increased “andeanization”. Apolistas and then Apoleños emerged from these interethnic mixes defined more geographically than ethnically.The Leco revival happens in an auspicious national and international context, but the Leco language was still spoken two or three generations ago on the Mapiri’s banks. It raises the question of social transformation and continuity: are we dealing with a case of acculturation, ethnogenesis, camouflage or resistance?

The Leco from North of La Paz were considered to have disappeared by the end of the 20th century; however in 1997, two groups of Leco re-emerged independently from each other, one in Larecaja and one in Apolo. In the former the claim was less violent than in the latter, where Quechua peasants share language, culture and kinship, and refuse to recognize the land rights and the identity of their “Indigenous Leco” neighbours. The thesis aims to understand ethnohistorically both resurgences, and tries to go beyond essentialism to understand the heterogeneous melting pot from where the Apoleños come. Apolobamba, because it connects highlands and lowlands, received Andean influences (puquina, aymara and quechua) early on. Its inhabitants, the Chuncho of the Incas then the Spaniards, show hybrid ethnolinguistic and socio-cultural features. The ethnic diversity was reduced in the 18th century Franciscan Missions, where the ethnolinguistic border between an Andean South and the “savages” of the North was drawn at the Tuichi river. The liberal Republican period, with the construction of a national identity, once again shrank regional diversity and increased “Andeanization”. Apolistas and then Apoleños emerged from these interethnic mixes defined more geographically than ethnically. The Leco revival happens in an auspicious national and international context, but the Leco language was still spoken two or three generations ago on the Mapiri's banks. It raises the question of social transformation and continuity: are we dealing with a case of acculturation, ethnogenesis, camouflage or resistance?