Browsing by Autor "Susi Loza Herrera"

Now showing 1 - 4 of 4

Comunidades vegetales de los bofedales de la Cordillera Real (Bolivia) bajo el calentamiento global
(2015) Susi Loza Herrera; Rosa Isela Meneses; Fabien Anthelme
High-Andean wetlands (bofedales) are one of the most threatened ecosystems in the face of global warming. Given the close relationship between bofedales and water, it is expected that glacial retreat will cause their gradual shrinkage. With three proxies of climate change (bofedal area, glacier influence and elevation) we inferred how these changes may affect plant communities. The hypotheses were 1) that loss in the area of bofedales should reduce plant diversity - the glacier influence and elevation could affect this relationship through effect on environmental heterogeneity and diversity – and 2) glacial retreat may indirectly affect diversity through changes in dominant species. We measured α and β additive diversity of plants in 20 bofedales (>4.400 m) in the Cordillera Real (Bolivia). Sixty three species were found (species richness: 5-22 /plot 1m²). Variations in bofedales area and glacial influence weren’t correlated with vegetation changes whereas diversity reduced at higher elevation. In reference to our second hypothesis, leaves of Oxychloe andina were shown more resistant to drought stress because of its higher leaf dry mass content (LDMC) than the other cushions, indicating that the bofedales dominated by O. andina may be drier and the communities are dominated by species that also can be found in drier environments. In contrast, communities of Distichia spp. are less tolerant to water deficit. If glacial retreat reduces water availability in the coming decades, the bofedales of O. andina may be more abundant at the expense of Distichia spp. creating challenges for the biodiversity conservation.
Market access and community size influence pastoral management of native and exotic livestock species: A case study in communities of the Cordillera Real in Bolivia's high Andean wetlands
(Public Library of Science, 2017) Quentin Struelens; Karina Gonzales Pomar; Susi Loza Herrera; Gaby Nina Huanca; Olivier Dangles; François Rebaudo
Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability. In these harsh mountains, unique and productive wetlands sustained by glacial water streams are of utmost importance for feeding cattle herds during the dry season. After the colonization by the Spanish, a shift in livestock species has been observed, with the introduction of exotic species such as cows and sheep, resulting in a different impact on pastures compared to native camelid species-llamas and alpacas. Here we explored some of the social-economical and environmental drivers that motivate Bolivian pastoralists to prefer exotic over native livestock species, based on 36 household surveys in the Cordillera Real. We constructed a Partial Least Squares Structural Equation Model in order to assess the relationships between these drivers. Our results suggest that the access to market influenced pastoralists to reshape their herd composition, by increasing the number of sheep. They also suggest that community size increased daily grazing time in pastures, therefore intensifying the grazing pressure. At a broader scale, this study highlights the effects of some social-economical and environmental drivers on mountain herding systems.
Métodos para cuantificar diversidad y productividad vegetal de los bofedales frente al cambio climático
(2014) Rosa Isela Meneses; Susi Loza Herrera; Ariel Lliully; Arely Palabral; Fabien Anthelme
Se espera que el rapido retroceso glaciar, resultado del cambio climatico iniciado hace muchas decadas pueda tener efectos negativos sobre la diversidad y productividad de plantas de los bofedales, a traves de cambios de su extension o area y de su distribucion altitudinal. Esto manifiesta la importancia y necesidad de entender la estructura y funcionamiento de estos ecosistemas ante el calentamiento del clima. Proponemos un protocolo metodologico para examinar las respuestas de las comunidades vegetales de bofedales alto-andinos frente al cambio climatico, tomando en cuenta en primer lugar variaciones de area y de altitud entre bofedales. Con 200 cuadrantes de 1 m² distribuidos a escala regional, proponemos hacer mediciones bioticas de riqueza especifica (numero de especies) y de cobertura relativa de cada especie de planta. Tambien proponemos medir el contenido de materia foliar seca como indice de productividad (LDMC, por sus siglas en ingles, leaf dry matter content). Describimos medidas abioticas como parametros fisicoquimicos (pH, conductividad electrica, y nutrientes) en el agua y sustrato sobre los que se desarrollan estas plantas. Dado que las comunidades estan dominadas por plantas en forma de cojin, tambien describimos metodos para caracterizar variaciones intra e interespecificas entre cojines. Se sugieren metodos practicos que optimizan el trabajo en campo y son aptos segun los objetivos de investigacion que se tengan. Se discute la pertinencia de los metodos sugeridos en este trabajo con otros metodos disponibles en la literatura, y de acuerdo con los resultados preliminares obtenidos, se comparan sus beneficios e inconveniencias.
Unraveling bofedal change and degradation: Multidimensional analysis of pastoral management, local knowledge, and image analysis in Sajama National Park, Bolivia
(Springer Science+Business Media, 2026) Q. Rosa Isela Meneses; Karina A. Yager; Manuel Prieto; Dan Slayback; Kevin Guzman; Susi Loza Herrera; Gabriel Zeballos; Corinne Valdivia