Browsing by Autor "Esther Valenzuela-Celis"

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Diet analysis of three rodent species sigmodontine in three cocoa production systems and forest in Alto Beni, Bolivia
(Asociacion Mexicana de Mastozoología A.C., 2020) Wendy Calizaya-Mena; Adriana Rico‐Cernohorska; Emilia García-Estigarribia; Esther Valenzuela-Celis
Alto Beni region in Bolivia, presents a mosaic of non-extensive family crops ranging from monocultures to agroforestry systems immersed in a matrix of secondary forest, while the primary forest remains on the steeper slopes. Very little is known about the biology of the rodent species that inhabit this area. Then, the objective of this work was to determine the diet and its variation among three species of sigmodontine rodents ( Akodon dayi, Euryoryomys nitidus and Oligoryzomys microtis ) from 11 agroforestry systems (SAF) of cacao (four traditional monoculture / simple SAF plots, three intermediate SAF and four complex SAF) and two secondary forests. We analyzed contents of the stomach, cecum and intestine for 41 O. microtis (simple-SAF n = 31, complex-SAF n = 4 and forest n = 6), for 11 E. nitidus (simple-SAF n = 6, intermediate-SAF n = 2, complex-SAF n =3 and forest n = 2) and for 10 A. dayi (simple-SAF n =5 and forest n =5). We calculated trophic niche width (Levin’s Index) and measured the degree of niche overlap (an estimate of competition), using Pianka’s Symmetric Overlaying Index. Significant differences in the diet specialization among species across habitats, were tested using the non-parametric Kruskal-Wallis test. A total of 55 food items were obtained and grouped into nine food categories: dicotyledonous vegetative structures, monocotyledonous vegetative structures, vascular tissue, spikelet, seeds, mycorrhizae, adult arthropods, larval arthropods, and others. The study species feed primarily on plants of the family Poaceae. No significant differences were found in the diet between species or between SAF and the forest ( P > 0.05); in addition, there was no evidence of a noticeable overlay of trophic niches by habit type. In the studied season, we found that: O. microtis and E. nitidus are herbivorous omnivore; “generalist” simple-monoculture-SAF and “less generalist” in complex-SAF; besides, O. microtis is “generalist” in forest and E. nitidus is “specialist” in complex-SAF and in forest; while, A. dayi is herbivore-insectivore; “generalist” in simple-monoculture-SAF and in forest. Our results indicate that there is a strong relationship between, the type of plot where they were found and food availability in each habitat.
Variación del daño por herbivoría en hojas de papa (Solanum tuberosum ssp. andigena) en diferentes grados de cercanía a la vegetación nativa en Combaya, La Paz
(Selva Andina Research Society, 2022) Emili Antonia Jiménez; Esther Valenzuela-Celis
Las tasas de herbivoría elevadas están relacionadas con la aparición de nuevas plagas afectando a las plantas de interés comercial, como la papa (Solanum tuberosum). Si bien el interés de los agricultores es conocer a los principales depredadores de tubérculos, también es necesario entender los patrones de herbivoría en otras partes de la planta. En sistemas agrícolas la estructura del paisaje está determinada por los parches de vegetación, las parcelas de cultivo y el desplazamiento de la fauna asociada. Este estudio evaluó el daño por herbivoría en hojas de papa en función de la cercanía a parches de vegetación nativa en el Municipio de Combaya (Departamento La Paz, Bolivia). Se midió el porcentaje de daño foliar, el nivel de daño, el área foliar y la riqueza de herbívoros en cinco cultivos de papa. Los resultados revelaron que el porcentaje de herbivoría en cultivos cerca de la vegetación es significativamente superior al de los cultivos alejados (ANOVA P<0.00023729, F=9.3046). Los cultivos cerca de la vegetación mostraron en promedio 8.266±0.859 % de herbivoría mientras que los cultivos alejados 5.909±0.585 %. En total se capturaron 5 morfo-especies de herbívoros asociados a los cultivos de papa: 3 en cultivos cercanos y 2 en los alejados de la vegetación. La vegetación nativa juega un rol importante porque permitiendo que la fauna aproveche los recursos de todo el paisaje.
Variation of herbivory damage on potato (Solanum tuberosum ssp. andigena) leaves in different degrees of proximity to native vegetation in Combaya, La Paz
(Selva Andina Research Society, 2022) Emili Antonia Jiménez; Esther Valenzuela-Celis
High herbivory rates are related to the emergence of new pests and are a problem for plants of commercial interest, such as potato (Solanum tuberosum). While the interest of farmers is to know the main tuber predators, it is also necessary to understand herbivory patterns in other parts of the plant. In agricultural systems, landscape structure is determinated by vegetation patches, crops and the movement of associated fauna. This study evaluated herbivory damage on potato leaves as a function of proximity to patches of native vegetation in the municipality of Combaya (La Paz, Bolivia). The percentage of leaf damage, dam-age level, leaf area and herbivore richness were measured in five potato crops. The results showed that close vegetation crops have significantly higher herbivory than far away ones (ANOVA P<0.00023729, F=9.3046). Close vegetation crops showed 8.266±0.859 % herbivory, while are away ones 5.909±0.585 %. In total, five morpho-species of herbivores were found associated with potato crops: 3 in crops near and 2 in crops far from the vegetation. The native vegetation plays an important role because it allows the fauna to take advantage of the resources of the entire landscape.