Browsing by Autor "Kazuya Naoki"

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Bracken fern does not diminish arbuscular mycorrhizal fungus inoculum potential in tropical deforested areas
(Springer Science+Business Media, 2021) Cecilia L. López; César Mayta; Kazuya Naoki; Jorge A. N. Quezada; Isabell Hensen; Silvia C. Gallegos
Comparación de modelos de distribución de especies para predecir la distribución potencial de vida silvestre en Bolivia
(2006) Kazuya Naoki; María Isabel Vargas; Ramiro Pablo López; Rosa Isela Meneses; Julieta Vargas
Comparación de modelos de distribución de especies para predecir la distribución potencial de vida silvestre en Bolivia Naoki, Kazuya Gómez, M. Isabel López, Ramiro P. Meneses, Rosa 1. Vargas, Julieta
(2006) Kazuya Naoki; María Isabel Vargas; Ramiro Pablo López; Rosa Isela Meneses; Julieta Vargas
Complexity of cacao production systems affects terrestrial ant assemblages
(Elsevier BV, 2023) Chloé Durot; Miguel Limachi; Kazuya Naoki; Marc Cotter; Natacha Bodenhausen; Luis Marconi; Laura Armengot
• Terrestrial ant species richness, composition and trophic roles were analysed. • Ants were sampled four times in a long-term trial comparing cacao production systems. • Ant species richness did not differ between production systems. • Ant composition differed according to the management intensity of the systems. Given the rapid changes in tropical agricultural production, the evaluation of different management practices has gained interest to determine the effects of land-use change on biodiversity. The conversion of forests into agricultural land is one of the main drivers of diversity loss. Agroforestry systems have been shown as a promising option to provide suitable yields in addition to conserving biodiversity. In this study we compared species richness and community composition of terrestrial ants in six different systems in a long-term experimental site established in 2009 in Bolivia: a full-sun monoculture and an agroforestry system under conventional management, a full-sun monoculture and an agroforestry system under organic management, a highly diverse and dense agroforestry system without external inputs and a secondary forest. Using pitfall traps, we sampled ants four times during a seven-year period (2015-2021). We collected a total of 85 ant species belonging to 6 sub-families and 41 genera. More than 80% of the species were recorded in less than 10% of the traps. Species richness did not significantly differ between the systems. However, species composition mainly differed between the fallow and the production systems, and within the latter, it followed the management intensity gradient, i.e., complex agroforestry, agroforestry and monocultures. The indicator species analysis clearly showed species exclusively associated with one or more production systems, whereas others were only associated with the secondary forest. Species with specialised trophic roles were more frequent in forest and agroforestry systems. Our results showed that the disturbance generated by cultivation was the main driver differentiating ant communities, but also reinforced the importance of the complexity and management intensity of the production system. These results have strong implications for landscape management and highlights the importance of preserving natural patches of forest but also diverse and complex agroforestry systems within the agricultural matrix for ant diversity conservation.
Continental-scale analysis reveals deep diversification within the polytypic Red-crowned Ant Tanager (Habia rubica, Cardinalidae)
(Elsevier BV, 2015) Pablo D Lavinia; Patricia Escalante; Natalia C. García; Ana S. Barreira; Natalia Trujillo‐Arias; Pablo L. Tubaro; Kazuya Naoki; Cristina Yumi Miyaki; Fabrício R. Santos; Darío A. Lijtmaer
Diversidad de mariposas diurnas (Lepidoptera: Nymphalidae) en bosques y cultivos de cacao en un área de bosque amazónico basimontano en Bolivia
(2021) Indyra Lafuente Cartagena; Kazuya Naoki; Adriana Rico‐Cernohorska; Fernando Guerra-Serrudo; Luis F. Pacheco
Tropical forests conversion to agriculture has increased in recent years, though often followed by land abandonment and subsequent conversion to secondary forest. In this study, we evaluated the effect of disturbance on Nymphalid butterfly assemblages in an area of mountain foothill forests in Bolivia by comparing the butterfly diversity and species composition among primary forests, secondary forests and cacao crops. Data were obtained in two seasons, dry and dry-to-wet transition, using two sampling methods (bait traps and hand net). Species richness and butterfly abundance were higher in the understory of primary forests than in crops during the transition season. The sampling method can influence the detection of community variation: with traps, we only detected seasonal variation, while we registered higher abundance in both types of forests than crops with manual sampling, with higher heterogeneity in the understory of primary forests than in crops. There was also a difference in butterfly species composition between crops and both types of forest. Although some understory butterflies are capable of inhabiting disturbed sites, we should highlight the importance of primary forest for the maintenance of specific species and groups that could be lost if the disturbance dynamics intensify. Finally, long-term studies are necessary to understand species dynamics in the area, both their seasonality and the interrelationship with available resources in each type of habitat.
Efecto de diferentes sistemas de producción de cacao de 3-4 años sobre la composición de un ensamble de hormigas terrestres
(2018) Miguel Limachi; Kazuya Naoki; Laura Armengot
Effect of shade and precipitation on germination and seedling establishment of dominant plant species in an Andean arid region, the Bolivian Prepuna
(Public Library of Science, 2021) Natalio Roque Marca; Ramiro Pablo López; Kazuya Naoki
Germination and seedling establishment are two critical processes in the life cycle of plants. Seeds and seedlings must pass through a series of abiotic and biotic filters in order to recruit as members of their communities. These processes are part of the regeneration niche of the species. In arid regions, the regeneration niche is frequently associated to facilitation by shade. Facilitation is a positive interaction between plants, in which one of them acts as a benefactor (the nurse) of the other (the beneficiary). The result of this interaction can be reflected in the increased growth, survival, and/or reproduction of the beneficiary plant. In this study, we determined experimentally the effect of shade and irrigation on the germination and early survival of dominant species of a semi-arid Andean region, the Bolivian Prepuna. An experiment with Acacia feddeana, Prosopis ferox, Cercidium andicola (woody species), Parodia maassii, and Oreocereus celsianus (cactus species) was carried out at an experimental garden in La Paz, Bolivia, with a bifactorial design, considering shaded and unshaded pots, subjected to two irrigation treatments (≈50 and 80 mm of rainfall during the whole study period). Microenvironmental conditions did not affect the seed germination of the woody species. However, they showed differences in seedling survival: A. feddeana survived better under shade, whereas P. ferox and C. andicola survived better without shade. Cercidium andicola, compared to P. ferox, was more affected by shade and low irrigation. Although germination success of cacti was low, both species germinated better under shade and with high irrigation. These results showed differences in the regeneration niche of dominant species of the Prepuna which may favor their coexistence and which may be characteristic of other dry Andean regions.
Effects of environmental variables and foliar traits on the transpiration rate of cocoa (Theobroma cacao L.) under different cultivation systems
(Springer Science+Business Media, 2020) Francisco Saavedra; Ernesto Jordan Peña; Monika Schneider; Kazuya Naoki
El pasado, presente y futuro en el uso de la estadística en estudios ecológicos en Bolivia
(2012) Kazuya Naoki
El uso del método de puntos de intercepción para cuantificar los tipos de vegetación y hábitats abióticos en los bofedales altoandinos
(2014) Kazuya Naoki; Rosa Isela Meneses; María Isabel Vargas; Carlos Miguel Landivar
Ensamble de hormigas en relación a cobertura vegetal en una zona periurbana de La Paz (Bolivia)
(2012) A. Bruno Miranda; Kazuya Naoki; Miguel Limachi
Las hormigas son frecuentemente utilizadas como bioindicadores de la integridad ecosistemica debido a su sensibilidad a cambios antropicos del medio ambiente, especialmente a cobertura vegetal, uso de tierra y contaminacion. El objetivo de este estudio fue relacionar el ensamble de hormigas a caracteristicas de diferentes tipos de vegetacion en una zona periurbana de la ciudad de La Paz, Bolivia. Los ensambles de hormigas fueron estudiados a traves de trampas de caida ubicados en 30 sitios. La vegetacion de cada sitio fue cuantificada por medio de linea de intercepcion segun sus caracteristicas fisonomicas y estructurales. Durante el estudio se registraron 14 morfoespecies de hormigas pertenecientes a cuatro subfamilias: Dolichoderinae, Formicinae, Myrmicinae y Ponerinae. Segun ordenacion por NMDS, el ensamble de hormigas se conformo en tres grupos asociados con el tipo de vegetacion: Arboleda, pajonal y prado. Esta asociacion fue parcialmente explicada por la seleccion de algunas morfoespecies de hormigas para las caracteristicas de vegetacion. Los resultados de este estudio apoyan la influencia de la vegetacion sobre el ensamble de hormigas y sugieren la potencialidad de uso de hormigas como bioindicadores en zonas urbanas.
Environmental gradualism explains variation in pollination systems of columnar cacti: Phylogenetic and trait evolution analyses
(Wiley, 2023) Damián Freilij; Daniel M. Larrea‐Alcázar; Ramiro Pablo López; Fernando Velarde Simonini; Kazuya Naoki; Cecilia Bessega
Abstract Aim The geographical dichotomy hypothesis (GDH) states several flowering plant groups have specialized pollination systems in tropical areas where resources are more reliable and pollinator communities tend to be more stable, than in extratropical areas. Our main goal was to understand the scope of the GDH and/or gradual environmental variation considering the evolutionary history of the pollination traits. Location Neotropical tropics and adjacent extratropics. Major taxa studied Columnar cacti. Methods Using a database composed of ~54 columnar cacti species (31.7% of the global columnar cactus species), four complex traits were analysed: pollination syndromes, reproductive systems, type of anthesis, and duration of anthesis. We conducted generalized linear models (GLMs), phylogenetic regressions, evolutionary trait optimization, and multivariate models with 19 bioclimatic variables and potential evapotranspiration. Results Weak phylogenetic signal was detected for all traits, giving consistent results between GLMs and phylogenetic regression analysis. The pollination syndrome and duration of anthesis varied with latitude, in contrast to the reproductive system and the type of anthesis. In the Southern Hemisphere, the pollinators were more diverse and the duration of anthesis was longer. Different evolutionary paths between hemispheres were detected and optimization showed a complex pattern in the evolution of traits, suggesting high homoplasy with multiple transformations by convergence and/or parallelism. The environmental models showed thermic seasonality may be at the core of the latitudinal variation of the pollination system. Main conclusions We did not detect a geographical dichotomy in pollination systems of the cacti, but rather a gradual change in different pollination attributes. Therefore, instead of a GDH, we propose an environmental gradient hypothesis (EGH). Environmental variables may be explaining the variation detected in pollination system traits by conditioning floral properties (morphology, phenology), diversity and distribution of pollinators, and/or coevolution occurrence. The complexity implied in these traits is consistent with high homoplasy levels and a differential evolutionary history between the hemispheres.
Evolution between forest macrorefugia is linked to discordance between genetic and morphological variation in Neotropical passerines
(Elsevier BV, 2020) Natalia Trujillo‐Arias; María José Rodríguez‐Cajarville; Eloisa H. R. Sari; Cristina Yumi Miyaki; Fabrício R. Santos; Christopher C. Witt; Ana S. Barreira; María Isabel Gómez; Kazuya Naoki; Pablo L. Tubaro
Género y productividad de las publicaciones en ecología en Bolivia: Un análisis de cuatro décadas
(2025) M. Isabel Gómez; Kazuya Naoki; Paola Velásquez‐Noriega
La disparidad de género en la investigación científica constituye un desafío global persistente. Estudios a nivel global documentan desequilibrios en la representación de investigadores y una brecha de género en la productividad, con una mayor producción académica masculina. Si bien esta tendencia es evidente a nivel mundial, la realidad boliviana en este ámbito sigue siendo poco explorada. En este contexto, el presente estudio analizó la relación entre el género y la productividad científica en ecología en Bolivia durante los últimos 40 años. A partir del análisis de 833 artículos publicados en tres revistas bolivianas, los resultados revelaron una menor productividad de las investigadoras en comparación con sus colegas masculinos. Aunque esta subrepresentación femenina persistió a lo largo del tiempo, la participación de mujeres como autoras experimentó un crecimiento constante (del 28% en 1980 al 44% en la década de 2020). El análisis de colaboraciones también mostró que los artículos con una mujer como primera autora tenían una mayor proporción de coautoras femeninas. A pesar de lo sugerido por otros estudios, nuestro análisis no reveló diferencias significativas en el número de citas recibidas en relación con el género del primer autor. Comprender estas brechas de género es crucial para identificar obstáculos profesionales para las mujeres, entender su impacto en la calidad y diversidad de la investigación, y fundamentar políticas que promuevan la equidad en la ciencia boliviana.
Glacier influence on bird assemblages in habitat islands of the high Bolivian Andes
(Wiley, 2021) Tatiana Cárdenas; Kazuya Naoki; Carlos Miguel Landivar; Quentin Struelens; María Isabel Gómez; Rosa Isela Meneses; Sophie Cauvy‐Fraunié; Fabien Anthelme; Olivier Dangles
Abstract Aim Climate projections for the upcoming decades predict a significant loss of ice mass particularly critical for glaciers in tropical mountains. In the dry landscapes of the southern Andes (from Southern Peru to Chile), this global trend has strong ecological impacts on high‐altitude wetlands that support a unique avifauna for feeding, roosting and nesting. As glacier runoffs are expected to affect the area and the quality of wetland habitats, these changes may potentially affect bird communities. To address this issue, we studied the structural and functional diversity of bird assemblages in glacier‐fed high‐altitude wetlands (>4500 m). Location Five valleys of the Cordillera Real, Bolivia. Methods We surveyed bird communities during dry, wet and intermediate seasons in 40 wetlands (total of 27,720 observations of birds and habitats from 540 transects) showing different degrees of dependence on glacial meltwater. We examined the potential effect of glacier retreat on bird communities through changes in wetland area and environmental quality and heterogeneity. Results We found strong relationship between wetland area and taxonomic and functional diversity, but not on phylogenetic diversity. Generalized additive models revealed that avian diversity was influenced by wetland's productivity and elevation and maximized at intermediate levels of glacier influence. Multivariate analysis further showed that habitat productivity and humidity, both potentially influenced by future glacial retreat trends, are the main drivers of bird community composition, with the wettest habitats being crucial for aquatic birds and uncommon species. Main conclusions Glacier retreat may significantly affect bird community diversity and composition through changes in both area and quality of high‐altitude wetlands, with a particular concern for aquatic birds.
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.
Importance of peatlands to maintain avian diversity in the Bolivian High Andes
(Wilson Ornithological Society, 2022) Mariela Yapu‐Alcázar; Kazuya Naoki
The High Andean peatlands are peat-accumulating wetlands dominated by cushion-forming plants and are embedded in a matrix of puna grasslands above 4,000 m. These ecosystems are an essential source of water and evergreen vegetation for wild and domestic animals and are considered sensitive to environmental alterations. We studied the birds' habitat and microhabitat preference in peatlands and their surrounding grasslands in the Cordillera Real, Bolivia. We established 3 parallel transects around 12 peatlands: (1) in peatland, (2) at 100–200 m from the peatland edge, considered as the transition habitat between peatlands and grasslands, and (3) in puna grasslands at >500 m from the peatland edge. We quantified bird abundance, species richness, and the availability of 8 microhabitats along 36 transects. We recorded 934 individuals of 34 species and found higher bird species richness and abundance in peatlands than in surrounding grasslands and transition habitats. We found that 26% of bird species were exclusive to peatlands. While most bird species common in peatlands were almost nonexistent in other habitats, most species associated with grasslands were also found in proximity to peatlands. A canonical correspondence analysis showed that bird species were associated with one or more microhabitats. The high abundance, bird species richness, and diet types in peatlands is probably related to the high primary productivity of peatlands and year-round availability of water. Degradation of these peatlands may reduce the abundance of regional bird communities, not only peatland specialists but also species in surrounding habitats.
Methods to evaluate the effects of domestic herbivores on the vegetation communities of bofedales
(2014) Mary Carolina García; Rosa Isela Meneses; Kazuya Naoki; Fabien Anthelme
Métodos para evaluar el efecto del pastoreo sobre las comunidades vegetales de bofedales
(2014) Mary Carolina García; Rosa Isela Meneses; Kazuya Naoki; Fabien Anthelme