Browsing by Autor "Enzo Aliaga Rossel"

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Bolivian river dolphin site preference in the middle-section of Mamoré River, upper Madeira river basin, Bolivia
(Asociacion Mexicana de Mastozoología A.C., 2020) Enzo Aliaga Rossel; Luis A. Guizada Duran
The South American river dolphins of genus Inia are distributed throughout the Amazon, Orinoco and Araguaia-Tocantins basins. They are categorized as Endangered and the knowledge on their basic ecology is still scarce. Therefore, investigation efforts must contribute to the knowledge and conservation of these species in their area of distribution. For the Bolivian river dolphin we used a database of 10 years of upstream and downstream surveys, accumulating approximately 6,100 km of double routes from three main rivers of the Upper Madeira River basin (Ibare, Mamoré and Tijamuchi) by following standardized methods where each encounter with a single or a group of river dolphins was registered. Preferred sites by Bolivian river dolphin were based on Kernel density estimation. This methodology considers the accumulated data of georeferenced sightings, generating a map of probability of occurrence in each river. In the three rivers, the accumulated density of sightings is concentrated in meanders and confluences, resulting in a high probability of sighting Bolivian river dolphin in these habitats. It was also identified that the number of Bolivian river dolphin sightings decreased over time in the upper Tijamuchi River. The Bolivian river dolphin preferred both meanders and confluence habitats. Between the Ibare and Tijamuchi rivers (Mamoré sub- basin), the distribution of the species tended to be more uniform. According to these results, it is important to reinforce the management of the Ibare-Mamoré municipal protected area, since important Bolivian river dolphin populations are concentrated there. Same trend was also shown in the lower-middle zone of the Tijamuchi River, suggesting the need of implementing conservation strategies in this area, where currently there are none.
Conservation status and natural history of Ctenomys, tuco-tucos in Bolivia
(Asociacion Mexicana de Mastozoología A.C., 2021) Scott Lyell Gardner; Sebastián Botero-Cañola; Enzo Aliaga Rossel; Altangerel Tsogtsaikhan Dursahinhan; Jorge Salazar‐Bravo
The genus Ctenomys consists of about 70 species and in addition to the Geomyidae of the Nearctic, Neotropical tuco-tucos represent a well-documented case of diversification in the subterranean biotype. Here we will: i) Provide an updated summary of the natural history of the 12 species of extant tuco-tucos from Bolivia; ii) Update information on distributions of each species; and iii) Using ecological niche modeling, evaluate recent and projected habitat transformation or habitat degradation within the known range of each species to provide a preliminary assessment of the preservation or conservation status of ctenomyids within Bolivia. We follow Gardner et al. (2014) and combine species summaries with both updated published and new data to compile a complete list of known extant species of tuco-tucos from Bolivia. Occurrence data for Ctenomys in Bolivia and surrounding areas were extracted from the database Arctos and GBIF. All individual specimen-based locality records were checked and georeferenced by referring to original museum collection records. We created species distribution models for the species with enough locality records using climate and soil data, while for the rest of the species we estimated the ranges based on the known occurrence localities. Finally, we quantified the amount of large-scale habitat conversion occurring within each species range, as well as the potential effect of climatic change on species distribution. Here we present information regarding the biology of tuco-tuco ( Ctenomys ) species known to occur in Bolivia, including unpublished natural history data such as habitat association, interactions and activity patterns gathered by the authors through extensive field work. Besides this, we estimated the current distribution of Ctenomys species, quantified large-scale habitat transformation within each species range and assessed the potential effect of climatic change on five tuco-tuco species. We found that the habitats within the ranges of C. boliviensis and C. steinbachi have experienced significant land-cover conversions in recent years. We also show that C. opimus , as well as the above mentioned species are expected to undergo range contractions resulting from climatic change by 2070. Our review shows that there is a dearth of information regarding natural history, taxonomy and distribution for many Bolivian tuco-tuco species. Nonetheless, the information presented here can be a tool for directing and focusing field studies of these species. This is of great importance if we take into account that most of the Bolivian tuco-tucos are subject to one or several conservation/preservation threats. These include: Habitat destruction via land use or climatic changes in conjunction with geographic ranges of Ctenomys that are small in areal extent and which in many cases are not adequately covered by protected areas.
Densidad y estructura poblacional de capibaras ("Hydrochoerus hydrochoerus") en la parte central del Río Mamoré (Beni, Bolivia)
(2014) Luis Guizada Duran; Enzo Aliaga Rossel
DETERMINACIÓN DE LOS PARAMETROS TEMPERATURA, pH Y CONCENTRACIÓN PARA LA NUEVA ENZIMA α-AMILASA Mg.
(2019) Jorge Fabio Yañiquez Vedia; Susana Huanca Lopez; Leslie Tejeda; Enzo Aliaga Rossel; J. Mauricio Peñarrieta Loria; Patricia A. Mollinedo Portugal
Los parámetros fisicoquímicos de pH, concentración y temperatura de las reacciones de las α-amilasas en sus diferentes aplicaciones, determinan la eficiencia de la reacción enzimática. El presente estudio muestra la relación entre los parámetros fisicoquímicos demostrándose que el pH es el parámetro determinante para la eficiencia máxima de la enzima. También se determinan los valores óptimos de estos parámetros para la reacción enzimática a pH 5 y T=50°C para una concentración de 5,6 U/mL de la enzima, α-amilasa-Mg, modificada de acuerdo a la patente 002-2017.
Encounter rates of the Bolivian river dolphin (Inia boliviensis) in northeastern Bolivia
(2018) Enzo Aliaga Rossel; Luis Guizada
This study provides information on seasonal distribution patterns for river dolphins in Bolivia.
Mamíferos consumidores de frutas y semillas de la chonta (Astrocaryum gratum, Arecaceae) en bosques submontanos y aluviales de Bolivia
(2014) Enzo Aliaga Rossel; Rosana Moraes
Translocation of trapped Bolivian river dolphins (Inia boliviensis)
(2020) Enzo Aliaga Rossel; Mariana Escobar-ww
The Bolivian river dolphin (Inia boliviensis), locally known as bufeo is an endemic species and categorized as Vulnerable in the Red Book of Vertebrates of Bolivia. Despite the fact that the Bolivian river dolphin is the only cetacean in land-locked Bolivia, knowledge about its conservation status and vulnerability to anthropogenic actions is extremely deficient. We report on the rescue and translocation of Bolivian river dolphins trapped in a shrinking segment of the Pailas River, Santa Cruz, Bolivia. Anthropogenic activities to alter the landscape and create agricultural land in the area include significant deforestation and irrigation channel construction and are likely to be a contributory factor causing the entrapment of these Bolivian River dolphins. The dolphins were trapped in shallow water in a 1 km section of river. Dry season water levels were rapidly falling and this section of river dried up completely. We collaborated with several institutions, authorities, and volunteers to translocate 26 Bolivian river dolphins, including calves, juveniles, and pregnant females. The dolphins were captured and transported using well-padded boats and vehicles and released into the Rio Grande. Each dolphin was accompanied by biologists who assured their welfare. No dolphins were injured or died during this process. If habitat degradation continue, it is likely that events in which river dolphins become trapped in South America may happen more frequently in the future.