Browsing by Autor "Guido Ayala"

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Distribution, ecology, and conservation of Xenarthra in Bolivia — update to 2021
(2021) Enzo Aliaga‐Rossel; Carmen J. Quiroga; Ximena Velez–Liendo; Alfredo Romero‐Muñoz; Zulia Porcel; Robert B. Wallace; Guido Ayala; María Viscarra; Erika Cuéllar Soto; Teresa Tarifa
We present an update on the taxonomy, distribution, ecology, threats, and conservation status of Bolivian Xenarthra (orders Cingulata and Pilosa) based on articles published between 2010 and 2021. The Andean hairy armadillo Chaetophractus nationi has been synonymized with the less threatened C. vellero sus. Cabassous squamicaudis has been revalidated for Bolivia. Dasypus kappleri has been divided into three species; D. beniensis is the species present in Bolivia. Cyclopes didactylus was divided into seven species; C. catellus is the species in Bolivia. Chlamyphorus was divided into two genera; Calyptophractus retusus is the species in Bolivia. Recent camera trap and biodiversity surveys extend records of Xenarthra into the dry forests of the central and southern Andes of Bolivia. No comprehensive population assessment or basic ecological studies were undertaken for any Xenarthra species in the country during the period. However, indirectly, armadillos and anteaters have been included in recent studies using camera traps to evaluate effects of forest management, forest fragmentation, agriculture, and hunting on terrestrial mammals. Deforestation is the major threat to Xenarthra, exacerbated by economic pressures, policy changes, and frequent extensive fires in the past decade. The majority of xenarthrans are affected by hunting for subsistence consumption, meat sales, and/or cultural purposes. Overall, the conservation status of Xenarthra species in Bolivia is thought to be relatively stable, with vast protected areas, indigenous territories, and certified forestry concessions where deforestation and hunting are limited. However, outside of protected areas, threats are increasing. Direct research on Bolivian Xenarthra is needed, especially studies on longterm population trends, habitat preferences, and distribution in less-studied and threatened ecosystems such as the Chiquitano Dry Forest and the Bolivian-Tucumn Forest.
Estructura trófica de la ictiocenosis en lagunas de la llanura inundable de los ríos Ichilo y Chapare, (Bolivia)
(2000) Guido Ayala; Karina Zambrana; Mabel Maldonado
TROPHIC STRUCTURE OF THE ICHTHYOCOENOSIS IN SHALLOW LAKES OF THE FLOODPLAIN OF THE ICHILO AND CHAPARE RIVERS (BOLIVIA) Se estudio la estructura trofica de la ictiofauna de cuatro lagunas de la varzea de los rios Ichilo y Chapare (Departamentos de Cochabamba y Santa Cruz; 16005' a 16°43'S y 64°48' a 64°72'W) mediante el analisis estomacal de 1111 ejemplares pertenecientes a 52 especies y capturados en cuatro fases hidrologicas de los anos 1994 y 1995. Se utilizo un indice alimentario para agrupar las especies, definiendose cuatro grandes categorias troficas: carnivoros, herbivoros, omnivoros y detritivoros. Los grupos mas variados en numero de especies fueron los omnivoros y carnivoros, en tanto que en numero de individuos fueron dominantes los carnivoros que representaron algo mas del 50% de la abundancia total, les siguieron los omnivoros y los detritivoros, siendo los menos abundantes los herbivoros. El analisis temporal y espacial de la estructura trofica mostro que las variaciones entre lagunas son poco notorias, mostrandose mas importantes las variaciones entre fases hidrologicas, que basicamente implican un aumento en la proporcion de herbivoros durante la fase de inundacion. Se presenta una red trofica para las lagunas, que tampoco mostro variaciones importantes ni entre lagunas ni entre fases hidrologicas. Estos resultados sugieren que la estructura trofica de estas lagunas seria diferente a las descritas para grandes rios de la Amazonia y de otras cuencas sudamericanas, debido a una menor importancia de las especies detritivoras, herbivoras y omnivoras frente a las carnivoras, ya una relativa estabilidad de la estructura frente a los cambios hidrologicos asociados a un pulso de inundacion corto y poco predecible. Palabras claves: Estructura trofica, redes troficas, peces, rio Ichilo, rio Chapare, lagunas de varzea, llanuras inundables, Bolivia. ABSTRACT The trophic structures of fish communities in tour Varzea lakes of the Ichilo and Chapare Rivers States of Cochabamba and Santa Cruz; 1605'16°43' S and 64°48'64°72'W) were studied during tour hydrologic seasons in 1994 and 1995 by means of stomach content analysis of 1 111 individuals, pertaining to 52 species. The alimentary index was used to group the species in the tour trophic categories of carnivores, herbivores, omnivores, and detritovores. The most diverse groups, in terms of species number; were the omnivores and carnivores. In terms of number of individuals, the carnivores where dominant, representing more than 50% of the total. Omnivores and detritovores were less common with herbivores being least abundant. Temporal and spatial analysis of the trophic structure showed that the differences between lakes were small, while variations between hydrological seasons were more important. This variation resulted in an increase in herbivores during the high-water season. Trophic webs for the lakes were developed. No important variations between lakes or between hydrologic seasons were observed. In sum due to the lesser importance of detritivores, herbivores, and omnivores compared to carnivores and due to a more stable structure with respect to hydrologic changes, the trophic structure of these lakes seems to be different from those described for large Amazon rivers or other similar south American river systems, such as the Orinoco and Parana river systems. Key Words: Trophic structure, trophic webs, fish, Ichilo River Chapare River, Varzea, lakes, floodplain, Bolivia.
Habitat differences in seed‐dispersing vertebrates indicate dispersal limitation in tropical bracken‐dominated deforested areas
(Wiley, 2024) Silvia C. Gallegos; César Mayta; Mariana Villegas; Guido Ayala; Kazuya Naoki; Josef Rechberger; V. D. Zambrana Rojas; María Viscarra; Nuria Bernal‐Hoverud; Mauricio Espejo
Abstract Shifting agriculture and anthropogenic fires are among the main causes of deforestation in the tropics. After fire and land abandonment, vast deforested areas are commonly dominated by the bracken fern Pteridium for long periods. Although forest regeneration in bracken‐dominated areas is mainly hindered by dispersal limitation, little is known about the role of seed‐disperser communities in slow forest succession. Our objective was to unravel the differences in the properties of the seed‐disperser communities between forests and bracken‐dominated areas to assess their role in dispersal limitation to foster ecological restoration. We compared species richness, diversity, abundance, and composition of seed‐dispersing birds, bats, and medium and large terrestrial mammals between both habitats in a montane forest of Bolivia. The species richness and diversity were similar for bats and higher for birds in bracken‐dominated areas than in the forest, but species composition was different between both habitats and groups. Although species composition was similar between both habitats for terrestrial mammals, the abundance was higher in the forest than in bracken‐dominated areas. Differences in species composition of seed‐dispersing birds and bats could be one of the main causes of dispersal limitation in forest regeneration in tropical bracken‐dominated areas. The few shared species between both habitats could explain the low seed rain of animal‐dispersed forest tree species in bracken‐dominated areas and the consequent hindered forest regeneration. Future studies relevant to natural forest regeneration should focus on analyzing the effects of animal‐attractants such as perches, artificial bat‐roosts, and seedling transplants on disperser communities, seed dispersal effectiveness, and forest regeneration. Abstract in Spanish is available with online material.
Large-scale occupancy monitoring as a tool for Andean bear (Tremarctos ornatus) conservation in the northern Bolivian Andes
(Elsevier BV, 2025) Robert B. Wallace; Robert Márquez; Herminio Ticona; Ariel Reinaga; Jesús Martínez; Mauricio Peñaranda; Guido Ayala; María Viscarra; Isaac Goldstein
We estimated the occupancy of the Andean bear ( Tremarctos ornatus ) and identified factors influencing its occupancy using simple single-season models and spatial replicates across a 38,145 km 2 area in the northern Bolivian Andes, spanning elevations from 402 to 4,581 m above sea level from the Apolobamba Range to Lambate in the Cordillera Real. This region encompasses portions of two priority conservation areas for the Andean bear. Presence was determined through detection of signs such as tracks, scat, feeding sites, trails, and nests. Occupancy was assessed at two scales: the home range scale (16 km 2 cells with 12 visits in 57 cells) and the habitat use scale (1 km 2 cells with 3 visits in 226 cells). At the home range scale, occupancy probability (ψ) increased with distance from human settlements (β = 2.49), slope (β = 1.40), and elevation (β = 1.31). At the home range scale, overall occupancy for sampled cells was (ψ) was 0.60 (SE = 0.08) with detectability (p) of 0.39 (SE = 0.04). Model-averaged predictions estimated ψ as 0.69 (SE = 0.09) in the study area and 0.66 (SE = 0.12) when extrapolated to the broader Tropical Andes of central and northern Bolivia and southern Peru. Predicted occupancy was higher within priority Andean Bear Conservation Units (ψ = 0.77, SE = 0.08) and protected areas (ψ = 0.80, SE = 0.08) compared to areas outside these units (ψ = 0.54, SE = 0.18) and protected areas (ψ = 0.59, SE = 0.16). At the use scale, habitat use decreased near secondary roads (β = 2.33) and areas with human presence (β = −1.19) but increased near protected areas (β = −0.49). These findings highlight a significant positive relationship between Andean bear presence and protected areas while indicating negative impacts of human activity. The sign-based occupancy approach proved effective and cost-efficient for landscape-scale monitoring, providing valuable insights for conservation decision-making.
RETO CIUDAD NATURALEZA LA PAZ: UNA EXPERIENCIA DE OBSERVACIÓN Y REGISTRO DE LA BIODIVERSIDAD URBANA
(2023) Cecilia Flores-Turdera; Robert B. Wallace; Álvaro Garitano‐Zavala; Carla Maldonado; Cynthya Jurado; Daniela Álvarez; Wilma Angulo; Guido Ayala; Isabel Gómez; Mayli Hayes
La ciencia ciudadana incentiva la participación de las personas en proyectos de investigación científica. Una de las iniciativas más conocidas es el concurso City Nature Challenge, dirigida a registrar la biodiversidad en las ciudades mediante la aplicación iNaturalist. La región metropolitana de La Paz, Bolivia, participó de este concurso en 2019 y 2022 con el nombre de Reto Ciudad Naturaleza, gracias al impulso de Wildlife Conservation Society (WCS) Bolivia, la Carrera de Biología y el Instituto de Ecología de la Universidad Mayor de San Andrés (UMSA), y el Museo Nacional de Historia Natural (MNHN), que conformaron un Comité Organizador. El objetivo fue fortalecer los vínculos de la población urbana con la naturaleza para generar datos sobre el conocimiento y conservación de la biodiversidad. Las actividades se basaron en la promoción y difusión del concurso, eventos de capacitación en el manejo de aplicación iNaturalist, registro fotográfico, identificación taxonómica y entrega de certificados a los participantes. En 2019, La Paz compitió con 158 ciudades y consiguió el octavo lugar en número de especies (3.005), el tercer lugar en número de participantes (1.500) y el segundo en número de observaciones (46.931). En 2022, participaron 447 ciudades. La Paz lideró en las tres categorías del concurso, con 137.345 observaciones, 5.320 especies y 4.296 participantes. Más allá de estos resultados, destaca el compromiso de la ciudadanía paceña con su biodiversidad, lo que repercute en un vínculo cada vez más estrecho entre la población urbana y su entorno natural.
Reto Ciudad Naturaleza, La Paz: una experiencia de observación y registro de la biodiversidad urbana
(District University of Bogotá, 2023) Cecilia Flores-Turdera; Robert B. Wallace; Álvaro Garitano‐Zavala; Carla Maldonado; Cynthya Jurado; Daniela Álvarez-Portugal; Wilma Angulo; Guido Ayala; María Isabel Vargas; Mayli Hayes
La ciencia ciudadana incentiva la participación de las personas en proyectos de investigación científica. Una de las iniciativas más conocidas es el concurso City Nature Challenge, dirigido a registrar la biodiversidad en las ciudades mediante la aplicación iNaturalist. La región metropolitana de La Paz, Bolivia, participó en este concurso en 2019 y 2022 bajo el nombre Reto Ciudad Naturaleza, gracias al impulso de Wildlife Conservation Society (WCS) Bolivia, la Carrera de Biología y el Instituto de Ecología de la Universidad Mayor de San Andrés (UMSA) y el Museo Nacional de Historia Natural (MNHN), los cuales conformaron un comité organizador. El objetivo fue fortalecer los vínculos de la población urbana con la naturaleza, en aras de generar datos sobre el conocimiento y la conservación de la biodiversidad. Las actividades consistieron en la promoción y difusión del concurso, eventos de capacitación en el manejo de iNaturalist, registros fotográficos, identificación taxonómica y entrega de certificados a los participantes. En 2019, La Paz compitió con 158 ciudades y consiguió el octavo lugar en número de especies (3005), el tercer lugar en número de participantes (1500) y el segundo en número de observaciones (46 931). En 2022 participaron 447 ciudades, y La Paz lideró en las tres categorías del concurso, con 137 345 observaciones, 5320 especies y 4296 participantes. Más allá de estos resultados, se destaca el compromiso de la ciudadanía paceña con su biodiversidad, lo que repercute en un vínculo cada vez más estrecho entre la población urbana y su entorno natural.