Browsing by Autor "Takayuki Yunoki"

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A metacommunity ecological approach to understanding the community organization of fish in artificial ponds of the Mamoré River floodplain in the Amazonian lowlands of Bolivia
(Springer Science+Business Media, 2018) Takayuki Yunoki; Luis V. Torres; Reinaldo B. Cholima
Bolivian Amazon lowland fish metacommunity data
(University of Natural Resources and Life Sciences, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU - Vienna, 2015) Takayuki Yunoki; Luís Torres
This dataset represents metadata from the paper Yunoki, T. and Torres, L. V. (2015): The role of water chemistry, connectivity and piscivory for ecological and evolutionary process structuring a fish metacommunity in the Bolivian Amazonian lowland. This study documents the spatial dynamics of fish metacommunity based on the dataset of 65 sites in two geographic patches of transparent black and clear waters of the Amazonian Manuripi and Itenez Rivers, which are separated by river valleys with turbid waters originating in the Andes and the savanna.
Ecología biocultural de sabanas de llanuras de inondación en los llanos del Beni
(Centre National de la Recherche Scientifique, 2019) Doyle McKey; José Luis Aramayo; Marcelo Amaro; Takayuki Yunoki; Bruno Roux; Alex Ovando; Rumsaïs Blatrix
International audience
Fish metacommunity dynamics in the patchy heterogeneous habitats of varzea lakes, turbid river channels and transparent clear and black water bodies in the Amazonian Lowlands of Bolivia
(Springer Science+Business Media, 2016) Takayuki Yunoki; Luis Torres Velasco
Fish-AMAZBOL: a database on freshwater fishes of the Bolivian Amazon
(Springer Science+Business Media, 2014) Fernando M. Carvajal‐Vallejos; Rémy Bigorne; América J. Zeballos Fernández; Jaime Sarmiento; Soraya Barrera; Takayuki Yunoki; Marc Pouilly; José Zubieta; Evans De La Barra; Michel Jégu
FUNCIONAMIENTO ECOLOGICO DE LAS LAGUNAS DE LA ZONA DE INUNDACIÓN DEL RIO MAMORÉ, (BENI-BOllVIA)
(1999) Marc Pouilly; Caria Ibañez; M.E Alcedo Gutiérrez; Takayuki Yunoki
ECOLOGICAL FUNCTIONING OF FLOODPLAIN LAKES OF MAMORE RIVER (BENI -BOLIVIA) El sistema del rio Mamore en la region de Trinidad, esta constituido por el lecho principal y por lagunas anexas, antiguos cauces. Estas son diferentes debido a su edad, morfologia, conexion y distancia al Mamore. El objetivo del presente estudio es el de comprobar la hipotesis que la zona de inundacion tiene una estructura espacial y temporal en cuanto a la distribucion de los organismos acuaticos (fitoplancton; zooplancton; peces). Ocho lagunas correspondiendo a un gradiente de distancia al rio Mamore, fueron muestreadas durante los dos meses extremos del ciclo hidrologico (marzo y octubre 1998). Las seis primeras lagunas se encuentran dentro del bosque galeria, sometidas a inundaciones anuales: dos estan cerca del lecho principal, dos al medio del bosque y dos en el limite entre el bosque y la sabana. Las dos ultimas se ubican en la sabana y desconectadas del sistema Mamore. La composicion cuantitativa de las tres comunidades de fitoplancton (59 generos), zooplancton (34 generos) y peces (92 generos) esta presentada para cada laguna y para las dos epocas. Los resultados evidencian una diferencia de composicion y de densidad entre las epocas, con mayor densidad y riqueza en epoca de estiaje. Al nivel espacial se observa, patrones de composicion que varian segun las comunidades. Palabra-Claves: Amazonia Boliviana, Zona de inundacion, Fitoplancton, Zooplancton, Peces. ABSTRACT Mamore river system is constituted by a main channel and lateral oxbow lakes. These annexes are different in age, morphology, connection and distance to the river. The aim of the study is to check the hypothesis that the floodplain aquatic units have a spatial and a temporal structure as regarding biological communities of phytoplankton, zooplankton and fish. Eight lakes situated on a distance gradient from the Mamore river were sampled in the two extreme months of the hydrological cycle (March and October 1998). Six oxbows lakes lie in the gallery forest and are under annual flood influence: Two are situated clase to the rivet; two in the middle of the forest and two at the limit between forest and savannah. The two ultimate lakes correspond to savannah fIar lakes which are generally disconnected from the Mamore system. The composition of the biological communities of phytoplankton (59 genus), zooplankton (34 genus) and fishes (92 genus) are presented for each oxbows or lakes and for the two sampling dates. Results showed differences in the composition and the density between dates with greater density and richness during the low water season. The spatial pattern is also different between the 8 lakes and different for each community. Keywords: Bolivian Amazonia, Floodplain, Phytoplankton, Zooplankton, Fish community.
Hydrologic control in llanos de Moxos, Amazonian lowlands of Bolivia
(MedCrave Group, 2018) Takayuki Yunoki
Ichthyofauna (Osteichthyes, Actinopterygii) from tributaries of the Beni and Mamor&eacute; rivers in the Llanos de Moxos wetland of the Bolivian Amazon
(Pensoft Publishers, 2025) Takayuki Yunoki; Aldo R. Echeverria; Reinaldo B. Cholima; Guido Miranda; Federico Moreno
We conducted ichthyological surveys in the Biata, Geneshuaya, Benicito, and Yata Rivers, as well as Dos Naciones Lagoon. We recorded 182 species, including new records for Bolivia, such as Jupiaba citrina Zanata & Ohara, 2009, Moenkhausia melogramma Eigenmann, 1908, Spinipterus cf. acsi Akama & Ferraris, 2011, Tatia cf. gyrina (Eigenmann & Allen, 1942), Cetopsidium orientale (Vari, Ferraris & Keith, 2003), Nemuroglanis cf. furcatus Ribeiro, Pedroza & Rapp Py&#8209;Daniel, 2011, and Batrochoglanis melanurus Shibatta & Pavanelli, 2005. Most of these species, reported for the first time in Bolivia, were previously collected in black&#8209;clear water streams located in the Upper Amazon and/or the lowlands around the Guiana Shield and Brazilian Shield, far from the study area.&nbsp;
In a niche‐neutral continuum, a set of theoretical models in a metacommunity operates simultaneously in patchy habitats
(Wiley, 2023) Takayuki Yunoki
This study investigated the origins and maintenance of biodiversity by integrating ecological and evolutionary mechanisms into a spatially-explicit synthesis between niche-based processes and neutral dynamics (ND). An individual-based model on a two-dimensional grid with periodic boundary conditions was used to compare a niche-neutral continuum induced in contrasting spatial and environmental settings while characterizing the operational scaling of deterministic-stochastic processes. The spatially-explicit simulations revealed three major findings. First, the number of guilds in a system approaches a stationary state and the species composition in a system converges to a dynamic equilibrium of ecologically-equivalent species generated by the speciation-extinction balance. This convergence of species composition can be argued under a point mutation mode of speciation and niche conservatism due to the duality of ND. Second, the dispersal modes of biota may affect how the influence of environmental filtering changes across ecological-evolutionary scales. This influence is greatest in compactly-packed areas within biogeographic units for large-bodied active dispersers, such as fish. Third, the species are filtered along the environmental gradient and the coexistence of ecologically-different species in each local community in a homogeneous environment is allowed by dispersals in a set of local communities. Therefore, the ND among the single-guild species, extinction-colonization trade-off among species of similar environmental optima and different levels of specialization, and mass effect, such as weak species-environment associations, operate simultaneously in patchy habitats. In spatially-explicit synthesis, characterizing where a metacommunity falls along a niche-neutral continuum is too superficial and involves an abstraction that any biological process is probabilistic; therefore, they are dynamic-stochastic processes. The general patterns observed in the simulations allowed a theoretical synthesis of a metacommunity and explained the complex patterns observed in the real world.
Niche-based process and neutral dynamics emerge the per capita ecological difference and equivalence among species at different spatio-temporal-environmental scales
(2020) Takayuki Yunoki
Reconciling niche-based process and neutral dynamics in a portion of an infinite system, the regional species pool may be already not free parameter, and the divergent ecological-evolutionary mechanisms may operate consistently. The individual-based model was implemented in the two-dimensional grid with periodic boundary condition. The model was explored using a fixed speciation rate, and a range of system sizes, dispersal rates, environmental structures and initial conditions of regional species pool. The model communities in the center of system had a fixed population size, and approximated from an area encompassing independent biogeographic units to an area packed in a biogeographic unit with open boundary conditions, and presented the three environmental structures; four humps, linear and random. Across scenarios, the number of guilds in system achieved first to a stationary state; then, the species richness converged eventually to a dynamical equilibrium through speciation-extinction balance. In simulations, the per capita ecological difference among species only contributed to the probabilities of immigration success, so the weighted lottery process was more efficient and immediate at higher dispersal rates. The increase of functional redundancy in model communities suggested that the relative role of neutral dynamics increased in an area encompassing independent biogeographic units. The variation partitioning based on canonical analysis inferred that not only the neutral dynamics among the species of single guild, but also the competition-colonization trade-off among the species of more than two guilds with similar environmental optimum and different levels of specialization operated in the spatial structures found within and among patchy habitats. Ecologist to disentangle the influence of alternative processes must shift focus from the contribution of local competitions and regional dispersals to detecting the spatio-temporal-environmental scales on which the per capita ecological difference and equivalence among species are emerged through divergent ecological-evolutionary mechanisms.
Reconstructing freshwater fishing seasonality in a neotropical savanna: First application of swamp eel (Synbranchus marmoratus) sclerochronology to a pre-Columbian Amazonian site (Loma Salvatierra, Bolivia)
(Elsevier BV, 2021) Prestes-Carneiro Gabriela; Takayuki Yunoki; Dufour Jean-Louis; Kelig Mahé; Philippe Béarez
Size estimation of Synbranchus marmoratus and Synbranchus madeirae (Teleostei) based on isolated cranial and post-cranial bones
(Centre National de la Recherche Scientifique, 2018) Gabriela Prestes-Carneiro; Philippe Béarez; Kareen Dillenseger; Takayuki Yunoki
The remains of South American swamp-eels are commonly recovered in pre-Columbian archaeological sites and swamp-eels are an important prey of piscivorous predators. In an attempt to assess the size classes of modern and archaeological fish from Bolivia, here we provide allometric regression equations for Synbranchus marmoratus and S. madeirae, resulting in total body length estimations on the basis of isolated skeletal elements. A total of 68 modern skeletons for Synbranchus marmoratus and 82 for Synbranchus madeirae were analysed. Measurements were taken on cranial (dentary, ectopterygoid, neurocranium, articular, hyomandibular, cleithrum) and post-cranial bones (first and second precaudal vertebrae). Our study shows that bone elements are highly correlated with total body lengths, which allows for a reliable reconstitution of Synbranchus size for paleontological, archaeological and dietary studies.
Trophic structure of fish assemblages from Mamoré River floodplain lakes (Bolivia)
(Wiley, 2004) Marc Pouilly; Takayuki Yunoki; Claudio Rosales; Leigh G. Torres
Abstract – The fish assemblage of the floodplain of the Mamoré River (Bolivia) was estimated in eight lakes, corresponding to four habitat types, situated on an environmental gradient related to the river distance: lakes situated near the river, in the forested floodplain, at the floodplain edge and lakes isolated in the savanna. This paper documents the diet of 71 fish species (among the 140 recorded) and compares the taxonomic and trophic structure of fish assemblages between four lake types. The diet analysis was conducted to determine five trophic guilds: algivores/iliophages, herbivores, zooplanktivores, invertivores and piscivores. The taxonomic and trophic structures of the fish assemblages were not similar in the different lake types of the Mamoré River. The trophic structure of assemblages showed a coarse pattern of dominance of algivores/iliophages and invertivores, but different situations were observed in relative abundance of the trophic groups in relation to the spatial position of the lakes (except for piscivores). Lakes close to the river appeared more favourable to the microphages (algivores/iliophages, zooplanktivores) although remote lakes appeared more favourable to the macrophages (invertivores, herbivores). These results support the general idea that fish distribution follows a pattern linked to the ecology of the species, and related to environmental characteristics of the lakes.
Update on the checklist of fish species of the Bolivian Amazon
(Pensoft Publishers, 2013) Pascal I. Hablützel; Takayuki Yunoki; Luis Torres Velasco
In 2010 and 2011 new checklists of fish species occurring in the Bolivian Amazon have been published. We add 21 species to these lists of which two are new reports for Bolivia (Apistogramma urteagai Kullander, 1986 and Vandellia sanguinea Eigenmann, 1917). The other 19 taxa have been reported earlier for the Bolivian Amazon. Their absence on previous checklists indicate the difficulties to compile an overview of the current literature on the fish fauna of the Bolivian Amazon. The ichthyofauna of Bolivia is still not entirely known and many species await formal descriptions. Future collection efforts and taxonomic reviews might rise the number of known Bolivian fish species considerably in the near future.