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While elucidating the evolutionary trajectory of green anacondas, we previously documented the existence of two distinct species, Eunectes akayima sp. nov. and Eunectes murinus (Linnaeus, 1758), that separated approximately 10 million years ago. Our research integrates a novel molecular clock approach, focuses on tectonic plate movements with fossil records as minimal chronological markers, and offers a refined understanding of speciation events in relation to major biogeographical occurrences in South America. Mitochondrial DNA analysis demonstrates a significant genetic divergence between the species, which is supported by a notable difference in sexual size dimorphism (SSD) intensity between the two species, along with other morphological differences. This paper also rectifies earlier oversights in the description of the new species and clarifies taxonomic ambiguities in compliance with the International Code of Zoological Nomenclature (henceforth ICZN). In addition, we designate a neotype for E. murinus to stabilize the group. In an effort to honor Indigenous nations, E. akayima sp. nov. derives its name from the Carib language, advocating for the inclusion of traditional names in scientific discourse. Our paper not only contributes to the taxonomic stability of anacondas but also advocates for the usage of Indigenous names in zoological nomenclature by adopting a more inclusive and flexible approach to the ICZN and eliminating unintended exclusionary practices that we have inherited in science as in other disciplines. [ABSTRACT FROM AUTHOR]

Anacondas, genus Eunectes, are a group of aquatic snakes with a wide distribution in South America. The taxonomic status of several species has been uncertain and/or controversial. Using genetic data from four recognized anaconda species across nine countries, this study investigates the phylogenetic relationships within the genus Eunectes. A key finding was the identification of two distinct clades within Eunectes murinus, revealing two species as cryptic yet genetically deeply divergent. This has led to the recognition of the Northern Green Anaconda as a separate species (Eunectes akayima sp. nov), distinct from its southern counterpart (E. murinus), the Southern Green Anaconda. Additionally, our data challenge the current understanding of Yellow Anaconda species by proposing the unification of Eunectes deschauenseei and Eunectes beniensis into a single species with Eunectes notaeus. This reclassification is based on comprehensive genetic and phylogeographic analyses, suggesting closer relationships than previously recognized and the realization that our understanding of their geographic ranges is insufficient to justify its use as a separation criterion. We also present a phylogeographic hypothesis that traces the Miocene diversification of anacondas in western South America. Beyond its academic significance, this study has vital implications for the conservation of these iconic reptile species, highlighting our lack of knowledge about the diversity of the South American fauna and the need for revised strategies to conserve the newly identified and reclassified species. [ABSTRACT FROM AUTHOR]

While elucidating the evolutionary trajectory of green anacondas, we previously documented the existence of two distinct species, Eunectes akayima sp. nov. and Eunectes murinus (Linnaeus, 1758), that separated approximately 10 million years ago. Our research integrates a novel molecular clock approach, focuses on tectonic plate movements with fossil records as minimal chronological markers, and offers a refined understanding of speciation events in relation to major biogeographical occurrences in South America. Mitochondrial DNA analysis demonstrates a significant genetic divergence between the species, which is supported by a notable difference in sexual size dimorphism (SSD) intensity between the two species, along with other morphological differences. This paper also rectifies earlier oversights in the description of the new species and clarifies taxonomic ambiguities in compliance with the International Code of Zoological Nomenclature (henceforth ICZN). In addition, we designate a neotype for E. murinus to stabilize the group. In an effort to honor Indigenous nations, E. akayima sp. nov. derives its name from the Carib language, advocating for the inclusion of traditional names in scientific discourse. Our paper not only contributes to the taxonomic stability of anacondas but also advocates for the usage of Indigenous names in zoological nomenclature by adopting a more inclusive and flexible approach to the ICZN and eliminating unintended exclusionary practices that we have inherited in science as in other disciplines.

Anacondas, genus Eunectes, are a group of aquatic snakes with a wide distribution in South America. The taxonomic status of several species has been uncertain and/or controversial. Using genetic data from four recognized anaconda species across nine countries, this study investigates the phylogenetic relationships within the genus Eunectes. A key finding was the identification of two distinct clades within Eunectes murinus, revealing two species as cryptic yet genetically deeply divergent. This has led to the recognition of the Northern Green Anaconda as a separate species (Eunectes akayima sp. nov), distinct from its southern counterpart (E. murinus), the Southern Green Anaconda. Additionally, our data challenge the current understanding of Yellow Anaconda species by proposing the unification of Eunectes deschauenseei and Eunectes beniensis into a single species with Eunectes notaeus. This reclassification is based on comprehensive genetic and phylogeographic analyses, suggesting closer relationships than previously recognized and the realization that our understanding of their geographic ranges is insufficient to justify its use as a separation criterion. We also present a phylogeographic hypothesis that traces the Miocene diversification of anacondas in western South America. Beyond its academic significance, this study has vital implications for the conservation of these iconic reptile species, highlighting our lack of knowledge about the diversity of the South American fauna and the need for revised strategies to conserve the newly identified and reclassified species.

As savanas da América do Sul representam entre 8 e 10% da cobertura das savanas globais. De forma dispersa, elas cobrem pouco mais de 2,29 milhões de quilômetros quadrados no continente, e representam o espectro mais úmido e mais biodiverso das savanas globais. As savanas sul-americanas apresentam considerável grau de endemismo e suas características climáticas e composição em espécies são bastante influenciadas por biomas florestais vizinhos, como a Amazônia e a Mata Atlântica. Savanas sul-americanas ocorrem sobre solos que variam de arenosos a argilosos, em altitudes desde cerca de 150 metros até em torno de 2.000 metros acima do nível do mar, e em enclaves tão pequenos quanto 50 km2 até extensões imensas como aquelas ocorrentes no planalto central brasileiro. Muitas destas savanas são sujeitas a alagamento periódico o que as tornam únicas na sua dinâmica. Este artigo apresenta a revisão de um conjunto de informações sobre as savanas ocorrentes no continente sul-americano, analisando conceitos e abordando desde suas principais características climáticas, até particularidades da vegetação e da flora, espécies mais comuns e atributos funcionais. Muitas destas informações estão organizadas em tabelas, facilitando o acesso a dados pontuais. Assuntos correlatos, como a toxicidade imposta pelo alumínio presente nos solos de muitas delas e a presença de formações florestais e campestres ocorrendo na paisagem junto às formações savânicas são apresentados de forma complementar. Este artigo cobre uma lacuna acerca das formações savânicas na América do Sul e vem contribuir para a divulgação do conhecimento deste importante, complexo, mal compreendido e ameaçado ecossistema.

Ginés de la Lanza is the last proponent of the pictorial line initiated by Hernando de Llanos in Murcia. The transmission of the models among painters belonging to the first half of the XVI century in the district of the old Diocese of Cartagena fostered the creation of a characteristic style that held the artistic hegemony for over fifty years. The study of this character and his inventory of goods allows us to understand the working method and the circulation of the typologies among this group. [ABSTRACT FROM AUTHOR]

Erythroxylum macrophyllum is a morphologically variable and widely distributed species complex in Central and South America with several sub-specific taxa and numerous species included in its synonymy. A single variety grows in the Colombo-Venezuelan savanna region which can be distinguished from the rest of the E. macrophyllum complex by the size of leaves, cataphyll and stipule characteristics, and shape of calyx lobes. A molecular phylogeny reconstructed from 519 nuclear genes also reveals that the savanna variety is more closely related to E. acuminatum and E. pauciflorum than E. macrophyllum. This phylogenomic evidence also suggests Erythroxylum sect. Macrocalyx, to which E. macrophyllum belongs, is a polyphyletic taxonomic section. We thus propose elevating this variety to specific status, as Erythroxylum savannarum. We provide an updated taxonomic description, information about its habitat and distribution, and justify its informal IUCN categorization of Near Threatened (NT). [ABSTRACT FROM AUTHOR]

Aim: Neotropical savanna birds occur north and south of, but mostly not in the Amazon Basin, except for a few isolated savanna patches. Here, we investigate the phylogeography of 23 taxa of Neotropical savanna birds co‐distributed across multiple isolated savanna patches to assess to what extent these species have a shared history of spatial diversification. We explore the role of the forested Amazon Basin as a vicariant barrier separating northern and southern populations, particularly focusing on the role of the coastal savannas of Amapá as a potential corridor of gene flow between northern and southern populations. Location: Neotropical savannas. Taxon: Aves. Method: We employ 775 mtDNA samples of 24 co‐distributed savanna bird taxa from all major savanna patches in South America to infer phylogeographic patterns. For this purpose, we use 24 genomic samples (UCEs) of a subset of 12 taxa in addition to the mtDNA samples to estimate timing of divergence across the Amazon Basin. We use phylogeographic concordance factors (PCF) to assess the level of phylogeographic congruence across co‐distributed taxa. Finally, we assess to which level physical distance drives genetic structuring by estimating isolation‐by‐distance (IBD) effects. Results: We find that although the study taxa generally do not share similar diversification patterns geographically, many have at least two distinct genetic groups, one north and one south of the Amazon Basin, that have only recently diverged. The timing of divergence between both areas is generally centered in the late Pleistocene, but somewhat variable, indicating there is no single vicariant event responsible for driving diversification. Main conclusions: Variability in divergence times indicates that landscape processes have not led to shared phylogeographic responses, which indicates a relatively minor role for vicariance. Shallow divergences suggest that Neotropical grassland habitats may have recently been more connected or that gene flow has played an important role. We did not find evidence of a single dominant corridor of dispersal between savannas north and south of the forested Amazon Basin. [ABSTRACT FROM AUTHOR]

Biological invasions affect virtually all ecosystems on earth, but the degree to which different regions and biomes are invaded, and the quality of information from different regions, varies greatly. A large body of literature exists on the invasion of savannas in the Neotropics and northern Australia where invasive plants, especially African grasses, have had major impacts. Less has been published on plant invasions in African savannas, except for those in South Africa. Negative impacts due to plant invasions in African savannas appear to be less severe than in other regions at present. As savannas cover about 60% of the continent, with tens of millions of people relying on the services they provide, it is timely to assess the current status of invasions as a threat to these ecosystems. We reviewed the literature, contrasting the African situation with that of Neotropical and Australian savannas. A number of drivers and explanatory factors of plant invasions in savannas have been described, mostly from the Neotropics and Australia. These include herbivore presence, residence time, intentional introductions for pasture improvements, fire regimes, the physiology of the introduced species, and anthropogenic disturbance. After comparing these drivers across the three regions, we suggest that the lower extent of alien plant invasions in African savannas is largely attributable to: (1) significantly lower rates of intentional plant introductions and widespread plantings (until recently); (2) the role of large mammalian herbivores in these ecosystems; (3) historical and biogeographical issues relating to the regions of origin of introduced species; and (4) the adaptation of African systems to fire. We discuss how changing conditions in the three regions are likely to affect plant invasions in the future.

Migration strategies in the avian world are often compared at the species level and evaluated relative to general ecology and constraints such as molting and breeding timetables. The advancement of tracking technology provides an opportunity to explore variation in more specific migration tactics within species and their populations as it relates to demographic and environmental factors throughout the annual cycle. We compare migration timing among 4 populations of Bobolink (Dolichonyx oryzivorus) from across the breeding range using data from light-level geolocators. The date of departure from the breeding grounds and the duration of southbound migration differed among breeding populations, and were more variable for eastern breeding populations compared to western populations farther from the main migration corridor. Despite variation in both timing and distance from the corridor among breeding populations, date of arrival at the major southbound stop in the Llanos of South America remained synchronous, but less so than previously described. Weekly flight distances were highly variable and did not differ among populations. Duration of northbound migration did not differ among populations and was half as long as the southbound migration. Our findings show Bobolink populations breeding near the species' relatively narrow migration corridor in the southeastern United States were more variable in terms of how they reached the first lengthy stop in the Llanos, suggesting more flexibility in migration tactics. Breeding locations were not associated, however, with the timing or duration of the remainder of their migratory schedule. Our findings support the hypothesis that food resources, both historical and present, drive and also modify the endogenous migration schedule of this flocking species with a split migration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pithecopus hypochondrialis is a species complex of at least three species. • Colour patterns lack diagnostic value despite statistical differences. • Cerrado, Llanos, and Guianan savannahs coincide with climatic refugia. • Our results validated a Pliocene Amazonian corridor for the first time. • Multiple pulses of connectivity likely ocurred through Plio-Pleistocene. Despite their limited vagility and pronounced habitat heterogeneity in the tropics, many anuran species have unexpectedly extensive geographic ranges. One prominent example of this phenomenon is Pithecopus hypochondrialis , which is found in the Cerrado, Guianan savanna, and Llanos domains, as well as isolated tracts of savanna and open habitat within the Amazon Forest. The present study employs an integrative species delimitation approach to test the hypothesis that P. hypochondrialis is in fact a species complex. We also reconstruct the relationships among the lineages delimited here and other Pithecopus species. In this study, we employ Ecological Niche Modelling (ENM) and spatiotemporal phylogeographic reconstruction approaches to evaluate a multitude of scenarios of connectivity across the Neotropical savannas. We identified three divergent lineages, two of which have been described previously. The lineages were allocated to a lowland Pithecopus clade, although the relationships among these lineages are weakly supported. Both the ENM and the phylogeographic reconstruction highlight the occurrence of periods of connectivity among the Neotropical savannas over the course of the Pliocene and Pleistocene epochs. These processes extended from eastern Amazonia to the northern coast of Brazil. The findings of the present study highlight the presence of hidden diversity within P. hypochondrialis , and reinforce the need for a comprehensive taxonomic review. These findings also indicate intricate and highly dynamic patterns of connectivity across the Neotropical savannas that date back to the Pliocene. [ABSTRACT FROM AUTHOR]

South America is home to some of the largest, most diverse grasslands on the planet, providing critical habitat for numerous plants and animals and vital resources for millions of people. Yet, at the dawn of the 21st Century, South America's grasslands are experiencing rapid, widespread and unprecedented impacts from activities such as pesticide use, drainage, urbanization, and conversion to industrial monocultures. In combination with the pervasive effects of global climate change, these impacts have the potential to ripple across grassland food webs in ways we still poorly understand. How do these impacts affect the behavior, ecology and population demographics of the numerous migratory birds that call these grasslands home? Given the historical lack of research on grassland birds across the New World, we know very little about how to best conserve them, much less which grassland migratory birds are currently impacted or likely will be in the near future. We argue that, by applying recent theoretical and technological advances in the field of movement ecology, rapid advances can be achieved in understanding grassland migratory birds in South America. We outline the current state of knowledge about grassland birds that migrate within South America, the main threats to their survival, and how the emerging field of movement ecology can contribute to understanding how to conserve and manage their populations. Only with information on the full annual cycle of these birds will we be able to formulate effective conservation and management plans to ensure the long-term viability of these unique species.

Abstract The Llanos region of Colombia represents one of the last large agricultural frontiers and is undergoing a rapid conversion from naturalized savanna to intensive agriculture with high agrochemical inputs and tillage. This massive land-use conversion has considerable impact on ecosystem services and biodiversity, particularly soil macrofauna, yet the full implications of this land-use shift for long-term agroecosystem productivity are poorly understood. To better elucidate potential land-use change impacts on agricultural production we used experimental microcosms in the greenhouse to evaluate how the common earthworm, Pontoscolex corethrurus, influences plant growth, nutrient uptake, and key soil properties relative to the application of lime and P fertilizer, both common soil fertility amendments in the region. Additionally, we aimed to explore the potential for interactions between earthworms and these amendments across distinct plant types, the grass Brachiaria decumbens and the legume Phaseolus vulgaris , which display different rooting patterns and nutrient acquisition strategies. Earthworms increased the biomass production of B. decumbens by 180% and N uptake by more than 240%, while P fertilizers and lime additions increased total biomass by less than 30% each for B. decumbens. Effects on P. vulgaris were similar, but less pronounced with earthworms increasing total biomass production by 35% and total plant N content by 70%, while neither lime nor P alone significantly influenced total biomass or N uptake. However, a significant interaction between earthworms and lime enhanced total biomass N content of P. vulgaris by more than 150% relative to microcosms without P. corethrurus , suggesting that earthworms can greatly enhance the efficacy of lime in soils. Additionally, we found that earthworms greatly improved soil aggregation, but only in the presence of plants, and that this effect was most prominent in microcosms with P. vulgaris. When testing treatment effects on soil P availability, only fertilizer P additions significantly influenced resin P, but not microbial biomass P. Our findings suggests the importance of developing management strategies that promote the activity and diversity of earthworms and other soil biota as a means to enhance crop productivity, resource use efficiency and a range of soil-based ecosystem services in the Llanos region and beyond. Highlights • Earthworms enhance plant growth more than lime or P fertilizer. • Lime only improves plant N uptake in the presence of earthworms. • Earthworms enhance soil structure, but only in the presence of growing plants. • Farm management should consider soil biological communities to optimize resource use efficiency. [ABSTRACT FROM AUTHOR]

Abstract As oil palm plantations continue to expand in Neotropical regions, identifying critical transitions in land use, at which animal communities can be drastically altered, is crucial for conservation planning. Here, we investigated potential unexpected change points (thresholds) in the response of terrestrial mammal's richness and community composition to increasing oil palm cover in the Llanos region of Colombia. We deployed camera traps to detect species across 56 sites (landscapes of ~220 ha each) and used segmented regression and Threshold Indicator Taxa Analysis (TITAN) for the identification of these thresholds. We found a negative linear relationship between the proportion of oil palm and species richness, but no evidence of a threshold. In contrast, we found strong signs of a community threshold when oil palm cover in the study area reached 45–75%, at which mammalian species composition (taxon-specific changes of abundance and occurrence frequency) drastically changed. When species were assessed individually, a significant threshold relationship to oil palm cover was found to occur in 10 of the 15 examined species, with four (squirrel, agouti, spiny rat, common opossum) having a negative drastic change at approximately 45% oil palm cover. Five species showed no evidence for any critical threshold (giant and lesser anteater, jaguarondi, white-tailed deer and raccoon). We used the community threshold identified above as a baseline to evaluate the conservation status of the four oil palm production zones in Colombia. We found that approximately 41% of the total area covered by oil palm in Colombia has crossed the identified threshold of 45–75%, suggesting urgent need for forest restoration to increase its extent if a collapse of their resident mammal communities is to be avoided. These findings provide guidance for the design of sustainable landscapes within production areas in Colombia to promote the conservation of terrestrial mammals. Highlights • We identified thresholds in mammals responses to oil palm cover increase in Colombia. • Species composition changed drastically in landscapes composed of 45–75% oil palm cover. • 41% of Colombian oil palm landscapes have crossed the identified threshold. • Urgent need for restoration in order to avoid the collapse of mammal communities • Our results provide guidance for designing sustainable oil palm landscapes in Colombia. [ABSTRACT FROM AUTHOR]

The Cusiana River sub-basin has been identified as a priority conservation area in the Orinoco region in Colombia due to its high species diversity. This study presents an updated checklist and identification key for fishes of the Cusiana River sub-basin. The checklist was assembled through direct examination of specimens deposited in the main Colombian ichthyological collections. A total of 2020 lots from 167 different localities from the Cusiana River sub-basin were examined and ranged from 153 to 2970 m in elevation. The highest number of records were from the piedmont region (1091, 54.0 %), followed by the Llanos (878, 43.5 %) and Andean (51, 2.5 %). 241 species distributed in 9 orders, 40 families, and 158 genera were found. The fish species richness observed (241), represents 77.7 % of the 314 estimated species (95 % CI=276.1-394.8). The use of databases to develop lists of fish species is not entirely reliable; therefore taxonomic verification of specimens in collections is essential. The results will facilitate comparisons with other sub-basins of the Orinoquia, which are not categorized as areas of importance for conservation in Colombia. [ABSTRACT FROM AUTHOR]

In the well-drained savannahs of Venezuelan Llanos, intensive agricultural activities could be causing damage to the soil, with negative consequences for the ecosystem. In order to avoid this problem, some agroecological alternatives are needed. Consequently, it is necessary to know the biologic dimension in this ecosystem, and within this, the soil macroinvertebrate community. The purpose of this work was to characterize this community in the natural savannah: its structure and diversity, its time variation and its relationship with the physical-chemical properties of the soil. A total of 72 samples were taken in different season along a period of time of 1405 days. The results revealed that the soil macrofauna had an average density of 243.5 ± 183.6 ind·m −2 , distributed in 32 families of 11 orders, with a diversity of N 1 = 4.5 ± 2.8 families. Coleoptera, Hymenoptera and Isoptera was the most dominants orders. The density, richness and diversity of families showed a temporal variation ( r ≥ −0.5; p < 0,05). Additionally, the structure of the soil macroinvertebrate community showed a vertical variation. The relationship with soil properties differed according families: Lampyridae, Aphodiidae and Formicidae had a positive correlation with soil macro-porosity (radius of the pores > 15 μm); Tenthredinidae and Tenebrionidae had a positive correlation with the micro-porosity (pores ≤ 15 μm). The community in general, correlated positively with soil porosity and negatively with bulk density. This suggests that these soil properties need to be considered when designing agroecological technics in this area. [ABSTRACT FROM AUTHOR]

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The Guiana Shield of South America contains savannas within one of the largest contiguous expanses of pristine tropical rainforest remaining in the world, but biodiversity in the grasslands is poorly known. In lowland Neotropical areas, bats typically comprise the most species-rich group of mammals. We compare the bat faunal community and phylogeography in the savanna habitats of the Llanos in Venezuela, Rupununi in Guyana, and Sipaliwini in Suriname. Measures of species diversity and relative abundance from standardized field survey methodology enable comparison among these three grassland regions. Genetic variation is summarized by DNA barcoding to examine biogeographic patterns across larger forest⁻savanna landscapes. A total of 76 species of bats is documented, of which 18 species are reported from all 3 savannas and 30 species are reported from only 1 of the savannas. Endemism is low with 5 taxa restricted primarily to dry, open habitats. However, 7 other species have divergent phylogeographic lineages associated with savanna populations. Although bat species are usually distributed over wide regions of the Neotropics, the habitat mosaics of the Guiana Shield have different faunal assemblages. Going back into the Miocene, the contractions and expansions of forest⁻savanna paleoenvironments over time have contributed to speciation and the current high levels of biodiversity in South America.

We report the presence of Boana wavrini in Arauca and Vichada departments (Llanos of Colombia). These localities extend the known range of this species by more than 283 km to the north from the previously known occurrences. In addition, we describe some aspects of the natural history of this species. [ABSTRACT FROM AUTHOR]

Lonchorhina marinkellei Hernández-Camacho and Cadena-G., 1978 is a bat commonly called Marinkelle's sword-nosed bat. It is one of the largest species of the genus and one of the rarest bats of northern South America, only known from 5 specimens and 1 locality in the eastern llanos of Colombia. Globally, it is considered "Vulnerable" by the International Union for Conservation of Nature and Natural Resources, mostly due to its restricted distribution and the continuing decline in the extent and quality of its habitat. [ABSTRACT FROM AUTHOR]

The llanos region in eastern Colombia exhibits great biodiversity, and is being threatened by agro-industrial processes such as oil palm plantations. However, information about the mammals associated with these landscapes is very limited. We measured richness and capture frequencies of medium and large sized mammals using camera traps in an oil palm plantation and surrounding natural ecosystems, in the seasonally flooded savannas of the Department of Casanare, Colombia. We identify 16 medium to large mammals, and two species of mice, with a survey effort of 3937 camera/days. Capture frequencies varied according to the land cover type. All species were present in the gallery (riparian) forest. Nine species were also detected inside the oil palm plantation and six in savannas. The mammals we found in the plantation were mainly mesopredators and generalist species, while the mammals detected in forest have more restricted diets. We discuss the importance of the gallery forests and artificial lagoons as landscape tools that could enhance diversity in these agro-ecosystems.

El objetivo de este trabajo fue identificar aislamientos de hongos ligninolíticos y celulolíticos que pudieran degradar desechos de cosecha y mejorar las características del suelo en los Llanos Orientales, se realizó un muestreo siguiendo la metodología de transepto y muestras integradas. Se obtuvo una cepa ligninolítica (005L Verticillium spp.) y 72 cepas celulolíticas. La comparación de los usos del suelo (sabana de pastoreo y bosque secundario) mostró que no existía una relación entre el número de géneros obtenidos y las características del suelo. Posteriormente, se realizó la cuantificación de la actividad celulolítica y ligninolítica de los aislamientos para identificar las cepas que posteriormente serían evaluadas en el sustrato natural pasto seco (Brachiaria spp.). Se encontraron dos cepas con alta actividad exoglucanasa (055C y 061C Penicillium spp.) y una cepa con alta actividad endoglucanasa (019C Trichoderma spp.) respecto al control Trichoderma viride. En el sustrato natural se evaluaron los consorcios de las cepas seleccionadas formados por pares: una ligninolítica y una celulolítica. Las pruebas mostraron que los aislamientos promisorios aumentaron su actividad enzimática en el sustrato pasto superando a los controles positivos (Pleurotus ostreatus para lignina y T. viride para celulosa) y que los consorcios no afectaron la capacidad enzimática de las cepas que los formaban. Por lo tanto, se recomienda utilizar estos consorcios para el desarrollo de biofertilizantes acondicionadores del suelo, empleando especialmente el consorcio formado por las cepas 005L (Verticillium spp.) y 055C (Penicillium spp.), que mostró alta actividad ligninolítica y celulolítica.The aim of this work was to identify lignolytic and cellulolytic fungal strains capable of degrading harvest waste and thereby improving the soil characteristics of the eastern Llanos of Colombia. Sampling was carried out using the transept methodology and integrated samples. A lignolytic strain (005L Verticillium spp.) and 72 cellulolytic strains were obtained. A comparison of soil usages (savanna grazing and secondary forest) showed no correlation between the number of obtained genera and soil characteristics. Selection of the strains to be evaluated in a dry-grass natural substrate (Brachiaria spp.) was carried out by quantification of lignolytic and cellulolytic activity. Two strains with high exoglucanase activity (055C and 061C Penicillium spp.) and a strain with high endoglucanase activity (019C Trichoderma spp.) relative to the Trichoderma viride control were selected and evaluated in the natural substrate in consortia formed by one lignolytic and one cellulolytic. The test showed that the enzymatic activity of the selected strains increased in the substrate grass, surpassing that of the positive controls (Pleurotus ostreatus for lignin and T. viride for cellulose) for both consortia. The use of the consortia is therefore recommended for the development of soil conditioning biofertilizers, especially that formed by the 005L (Verticillium spp.) and 055C (Penicillium spp.) strains with high lignolytic and cellulolytic activity.

La dinámica geográfica de la agricultura es un proceso complejo, que se expresa en desiguales patrones de especialización y distribución de la producción agrícola en las distintas regiones de un país a lo largo del tiempo. En la agricultura vegetal generalmente se privilegian los cambios en producción, superficie cultivada y rendimientos de los principales cultivos regionales. Este trabajo efectúa un análisis exploratorio de la superficie cosechada y los rendimientos del maíz, principal cereal de la agricultura venezolana, con el propósito de conocer las variaciones temporales y espaciales de la especialización productiva del cultivo durante el período 1984-2004. Un análisis multivariado del índice de especialización productiva permitió definir un patrón espacial de referencia en las entidades federales del país, a partir del cual se establecieron las variaciones quinquenales de la producción del rubro durante el período. Se concluye que tanto la disminución general, como la relocalización del índice de especialización productiva, no han favorecido la configuración de un patrón regional consolidado y sostenido del cereal en los llanos altos de Venezuela, tal como se observa en las praderas templadas del norte y sur del continente.

Trypanosoma vivax has been associated with asymptomatic infections in African and South American buffalo. In this study, T. vivax was analyzed in water buffalo ( Bubalus bubalis ) from Venezuela in a molecular survey involving 293 blood samples collected from 2006 to 2015 across the Llanos region. Results demonstrated constant infections (average 23%) during the years analyzed. In general, animals were healthy carriers of T. vivax with low levels of parasitemia and were diagnosed exclusively by TviCATL-PCR. However, an outbreak of severe acute infections mostly in dairy animals was reported during a prolonged drought affecting 30.4% of a buffalo herd (115 animals examined). During the outbreak, animals exhibiting anemia and neurological disorders developed fatal infections, and 7% of the herd died within nine months before treatment against trypanosomosis. Microsatellite locus genotyping (MLG) of T. vivax samples before and during the outbreak revealed similar genotypes, but outbreak isolates exhibited the most divergent MLG. Venezuelan samples from symptomless and sick buffalo did not share the MLGs previously detected in asymptomatic Brazilian buffalo. Trypanosoma evansi was not detected in the herd examined during the outbreak. However, as expected Babesia sp. (62.6%) and Anaplasma sp. (55.6%) infections were highly prevalent in asymptomatic buffalo in the studied areas. This is the first South American outbreak of highly lethal acute T. vivax infections in water buffalo. Our results suggest that chronically infected and asymptomatic buffalo living in areas of enzootic equilibrium can develop symptomatic/lethal disease triggered by stressful scarcity of green forage and water during long droughts, inappropriate management of herds and likely concomitant anaplasmosis and babesiosis. Altogether, these factors weaken buffalo immune defenses, allowing T. vivax to proliferate and, consequently, allowing for progression to wasting disease. [ABSTRACT FROM AUTHOR]

Populations of the Orinoco crocodile (Crocodylus intermedius) have not recovered from past exploitation, and current abundances cannot be used for assessing the suitability of habitats they occupy. Growth constitutes an alternative way of assessing habitat quality. Since 1990, more than 9000 captive-reared Orinoco crocodiles have been released into the Venezuelan Llanos. In the present study, the growth rates of 127 recaptured crocodiles from different regions were compared. All individuals from Middle Cojedes and the Aeolian savannahs grew slower than expected by the von Bertalanffy model, whereas individuals from Caños in the Apure floodplains grew faster than expected. These inferences are corroborated with growth rate measurements for crocodiles under four years of age, which were lowest in Middle Cojedes (average of 14.1 cm/ year) and highest at Caños (43.3 cm/year). Low growth rates can be explained by habitat deterioration due to human activities, and high growth rates in the Caños support that the lower reaches of whitewater rivers offer favourable conditions for the species. Crocodiles in high quality habitats may reach sexual maturity in six years, whereas more than a decade is required in poor-quality habitats. [ABSTRACT FROM AUTHOR]

A fin de describir la variabilidad espacio temporal de las comunidades de plantas acuáticas en un humedal de los Llanos de Venezuela, se estudiaron su riqueza y abundancia, en 14 hábitat, durante un ciclo anual. En los transectos de estudio se identificó un total de 69 especies. Según el análisis de diversidad con interacción de Alatalo y Alatalo el aspecto temporal, es decir el régimen anual de lluvia-sequía y la consecuente variación del nivel del agua, es el factor que ejerce mayor influencia sobre la riqueza de especies, en relación al aspecto espacial, o tipo de hábitat. Según el índice geométrico de las distancias euclídeas, se concluye igualmente que la variación en la abundancia de especies se debe más a las fluctuaciones hidrométricas (estacionalidad) que al hábitat considerado.Spatial-Temporal variability of aquatic plant communities in the Venezuelan Llanos. The richness and abundance of aquatic plant communities were studied in 14 habitats of the Venezuelan "llanos" (07º35’- 07º55’ N - 68º50’-69°00’ W, Apure) during an annual cycle. Annual means were 27ºC, 115 mm rainfall and 77% relative humidity. A permanent transect was set in each habitat (ten consecutive square meter quadrats from the shore to the water). The plants and the area they covered in each quadrat were recorded monthly for a year. The total richness was 69 species. Alatalo and Alatalo’s diversity analysis indicats that season, and its correlate, water level, influence species diversity and abundance more than habitat (spatial factor: geometric index-Euclidean distance). Rev. Biol. Trop. 54(2): 403-413. Epub 2006 Jun 01.

Copyright of Journal of Field Ornithology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Richness (alpha and beta diversity), abundance and dominance of bioforms of aquatic vegetation in a wetland of the Orinoco floodplains in Venezuela, studied over an annual cycle are described. In a lowland extension of 65,000 hectares including a whole range of aquatic habitats (shallows, marshes, ponds and streams), 197 species belonging to 122 genera and 56 families were recorded. Beta diversity was higher in lentic than in lotic wetlands, the emergent rooted bioform being the most abundant in all habitats and throughout the year. Considering the most persistent species (spatially and temporally), Eichhornia crassipes (Mart) Solms., Hymenachne amplexicaulis (Rudge) Nees and Luziola subintegra Swallen obtained the highest relative importance values. The most abundant species in all environments and throughout the year was Salvinia auriculata Aubl. Brief comments on the limited use of these aquatic plants are given.

Copyright of Tropical Conservation Science is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the mid-twentieth century, renewed colonization of the Llanos region of Colombia brought escalated violence to the closely related Guahibo and Cuiva peoples. This violence was made public by two dramatic episodes that became international scandals: a December 1967 massacre of sixteen Cuivas at La Rubiera Ranch, and a 1970 military crackdown on an uprising by members of a Guahibo agricultural cooperative in Planas. The scandals exposed both particular human rights abuses and the regional tradition of literally hunting indigenous people, and provoked widespread outrage. While contemporaries treated these events as aberrations, they can best be explained as the consequence of policies that organize and manage frontiers. Both events took place in a region undergoing rapid settlement by migrants, affected by cattle and oil interests, missionaries, the Colombian military, and U.S. counterinsurgency trainers. This paper draws on archival research to trace the events involved and explains their relation to globally circulating policies, practices, and ideas of frontier making. It illustrates how Colombians eager to expand their frontier in the Llanos emulated and adapted ideas of human inequality, moral geographies that make violence acceptable in frontier areas, economic policies that dispossess native peoples, and strategies of counterinsurgency warfare from distant sources. Ironically, their quest for modernity through frontier expansion licensed new deployments of "archaic" violence. The Llanos frontier was thus enmeshed in an interchange of frontier-making techniques that crisscrosses the world, but particularly unites Latin America and the United States. [ABSTRACT FROM AUTHOR]

The llanos region in eastern Colombia exhibits great biodiversity, and is being threatened by agro-industrial processes such as oil palm plantations. However, information about the mammals associated with these landscapes is very limited. We measured richness and capture frequencies of medium and large sized mammals using camera traps in an oil palm plantation and surrounding natural ecosystems, in the seasonally flooded savannas of the Department of Casanare, Colombia. We identify 16 medium to large mammals, and two species of mice, with a survey effort of 3937 camera/days. Capture frequencies varied according to the land cover type. All species were present in the gallery (riparian) forest. Nine species were also detected inside the oil palm plantation and six in savannas. The mammals we found in the plantation were mainly mesopredators and generalist species, while the mammals detected in forest have more restricted diets. We discuss the importance of the gallery forests and artificial lagoons as landscape tools that could enhance diversity in these agro-ecosystems. [ABSTRACT FROM AUTHOR]

Between 1983 and 1992, the authors conducted an archaeological project that involved five years of survey and excavation in a 450 km² study region that included portions of the high llanos (savanna grasslands) and adjacent Andean piedmont in the state of Barinas, Venezuela. Fieldwork (in 1983-1988) was followed by four years of laboratory analysis in the Departamento de Antropologa at the Instituto Venezolano de Investigaciones Científicas (IVIC) in Altos de Pipe, state of Miranda. Our project was designed to investigate whether during pre-Hispanic times the study region had witnessed the development of a chiefdom, which we defined as a regional (multivillage) polity led by a paramount chief who ruled from a regional center and presided over a chiefly administration that was centralized but not internally specialized. Before beginning the fieldwork, we conducted a review of the historical literature concerning the indigenous societies encountered by the first Europeans to explore this part of Venezuela. These early accounts described various independent regional-scale societies comprising numerous villages, politically unified under the leadership of a paramount chief. This led us to wonder about the antiquity of chiefly societies and their territorial extent in our study region, so we developed a research design to explore whether chiefdoms had emerged there in pre-Hispanic times. Drawing upon the abundant theoretical and empirical literature on chiefdoms, we set forth a series of expected archaeological manifestations of chiefdom organization, grouped as follows: regional hierarchy and integration, size of the regional polity territory or territory administered, regional political center, social differentiation, political economy and village economy, ceremonialism, exchange, and warfare. We were also interested in evaluating explanatory models of chiefdom formation that emphasize a variety of causal factors, including local resource control, agricultural intensification, population growth, warfare, long-distance exchange, and ritual-ideological legitimization. Our fieldwork comprised three seasons of regional survey, during the summer months of 1983-1985, followed by two dry seasons (January-May) of excavation in 1986 and 1988. On survey we recorded a total of 103 archaeological sites in our study region that was centered on the Canaguá River valley, extending across the high llanos (savanna grasslands) and adjacent Andean piedmont. Site occupations pertained to two chronological periods: an early period dating to a.d. 300-1000 and a later period dating to a.d. 1000-1850, taking our coverage into the early historic period. We called the earlier of these occupations on the high llanos the Gaván complex, divided into the Early Gaván phase (a.d. 300-550) and the Late Gaván phase (a.d. 550-1000), the latter of which exhibited many of the characteristics consistent with the expected archaeological manifestations of a chiefly society. There was convincing evidence of a regional hierarchy. We recorded 34 habitation sites and two drained-field agricultural sites dating to the Late Gaván phase. Taking both site size and mounded architecture into account, we were able to define a three-tier settlement hierarchy in the region, with the 33 ha site of B12 as the sole first-tier center with the region's largest earthen mounds, five other sites (B17, B21, B25, B30, and B97) as second-tier centers with smaller earthen mounds and ranging in size from 4.6 to 9.4 ha, and the remaining 28 habitation sites as third-tier villages that lacked mounds and varied in size from 0.5 to 5 ha. Regional integration during the Late Gaván phase was evidenced by an elaborate network of calzadas (earthen causeways or raised roads) that linked the first-tier center of B12 to four (and possibly five) of the second-tier sites and many of the third-tier sites. Our excavation strategy was designed to recover samples from all three tiers of the settlement hierarchy. We carried out excavations at five Gaván-complex habitation sites (B12, B97, B17, B21, B26) as well as at the drained-field site of B27. The size of the regional polity during Late Gaván times is consistent with the expected territorial extent of a chiefdom, which for theoretical reasons is not likely to exceed a radius of about one half-day of travel from the regional center; the reason is that such a territory could be managed by the regional leadership at the center without having to establish specialized subsidiary centers of regional administration. The distance between the first-tier center of B12 and the farthest village within its political region was about 17-18 km, and the total territory would have been roughly 290 km2. No part of the regional polity's domain would have lain beyond a half-day of travel by foot from the first-tier center, as we would expect for a chiefdom. The site of B12 is consistent with the expectations for a regional chiefly center: larger in size and with a more formalized and imposing community layout than the other sites in the polity. During the Late Gaván phase, B12 covered more than three times the area of the next-largest site. The most impressive earthen mounds in the region were found at B12, which featured a 500 m long avenue lined by house mounds, with the two largest mounds, probably ceremonial in nature, facing each other from opposite ends of the avenue. B12 was also the only site circumscribed by an earthwork (as can be seen on the cover of this monograph) that probably had defensive functions. We judge the amount and diversity of public architecture at B12 to be consistent with the expected range for a chiefdom. Our excavations at several Gaván-complex sites found evidence of pervasive social inequality or differentiation during the Late Gaván phase, manifested by the differences between individual burials, between households, and between residential sectors within sites. Such institutionalized social differences would have helped to legitimize and reinforce the centralized but not internally specialized administrative organization of the Late Gaván chiefdom. Our Late Gaván phase data are also consistent with the expectations for the political economy and the village economy of a chiefdom. Evidence of agricultural intensification was found in the form of drained fields capable of doubling the crop yields of ordinary fields. Since there were no signs of local or regional population pressure, we conclude that the main purpose of these drained fields was to produce a surplus, which was sent to the regional leadership at B12 by way of the calzada system that linked the drained fields to the first-tier center. At the same time, local villages pursued a variety of productive activities consistent with basic economic self-sufficiency. The centralized political economy of the regional chiefdom was grafted onto a locally self-sufficient village economy that was capable of generating a surplus as part of its contribution to the regional polity. The largest and most elaborate ceremonial facilities of the Late Gaván phase were found at the regional center of B12, a pattern consistent with the expected archaeological manifestations of a chiefdom, where ritual can play an important role in legitimizing regional authority. Also, the distribution of imported luxury goods at Late Gaván sites was consistent with the expectations of a model of chiefly prestige-good exchange; exotic items obtained by the regional elite through long-distance exchange may be sent to secondary elites within the region, as a form of payment for the latter's allegiance and assistance in mobilizing surplus on the local level. Probably as a consequence of such a two-way flow of surplus and prestige goods, certain exotic items (polished stone ornaments from the Venezuelan Andes and beyond) were found in relative abundance in our excavations at a second-tier center. It was at the regional center of B12 where we recovered the most evidence of warfare, consistent with models that view elite-directed warfare as an effective strategy for fomenting political cohesion in a regional chiefdom. B12 was circumscribed by an impressive oval earthwork that our excavations showed was topped by a palisade, similar to the defensive constructions described for 16th-century Venezuelan chiefdoms. B12 apparently suffered repeated attacks during the Late Gaván phase, as evidenced by the recurring layers of charcoal and burned earth in the profile of the site's largest mound. The widespread distribution of burned daub fragments in our test pits, especially in the uppermost levels, indicated that the regional center was completely abandoned after a final, catastrophic attack, which may have been launched against the Late Gaván chiefdom by a rival polity based in the Acequia-Anaro River drainage, the next major valley to the southwest. Since our Late Gaván phase data are consistent with the proposed archaeological expectations of a chiefly society, we also assess a series of explanatory models of chiefdom formation that have been proposed in recent years by anthropologists and archaeologists. Our method for testing these models involves an analytical comparison between the Early Gaván phase, when our study region shows no evidence of chiefdom organization (but was occupied by three small villages, one of which, B12, was larger than the others), and the Late Gaván phase, when multiple lines of evidence indicate that our study region was occupied by a chiefdom. To test each model of chiefdom formation, we determine whether the proposed causal variable was differentially associated with the B12 site during both the Early Gaván and Late Gaván phases, that is, over the time frame in which B12 was transformed from the largest of three small villages into the first-tier center of a regional chiefdom. Using data on changes over time in occupation area, architecture, and artifact distributions, we assess models that place causal importance on local resource control, population growth, warfare, long-distance exchange, and ritual-ideological legitimization in the formation of chiefdoms. Our analytical results are not consistent with models of chiefdom formation that attribute causal importance to ritual and long-distance exchange. Although these factors figured significantly in the dynamics of the developed Late Gaván chiefdom, they do not appear to have been instrumental in this chiefdom's emergence. By contrast, our results do provide support for models that highlight local resource control, population growth, and warfare in the formation of chiefdoms. Not only were these factors important in the operation of the Late Gaván chiefdom, but, according to our analyses, they also played key causal roles in the initial appearance of chiefdom organization around a.d. 550. [ABSTRACT FROM AUTHOR]

Wells located in the Colombian Andean foreland often produce biodegraded hydrocarbons and relatively fresh water (total dissolved solids concentrations of 2000 mg l−1 dominate across most of the basin). The ratio of water to hydrocarbon in the produced fluids is high and has often been interpreted by explorationists and simulation engineers as being due to massive meteoric water invasion. To challenge this hypothesis, previously published and existing data are compiled here, along with 68 new water samples collected from both the surface (rivers) and subsurface (production wells), which are analyzed for major elements, salinity, and stable isotope compositions. The data indicate a mixed origin for the water, which involves formation water, meteoric water, and a third source that we interpret as being related to diagenetic processes (such as clay dehydration). Analyses of the variation of the parameters from north to south and west to east allow us to define the mixtures as coming from waters of different origins and make it possible to determine the relative contribution of each source. [ABSTRACT FROM AUTHOR]

Richness (alpha and beta diversity), abundance and dominance of bioforms of aquatic vegetation in a wetland of the Orinoco floodplains in Venezuela, studied over an annual cycle are described. In a lowland extension of 65,000 hectares including a whole range of aquatic habitats (shallows, marshes, ponds and streams), 197 species belonging to 122 genera and 56 families were recorded. Beta diversity was higher in lentic than in lotic wetlands, the emergent rooted bioform being the most abundant in all habitats and throughout the year. Considering the most persistent species (spatially and temporally), Eichhornia crassipes (Mart) Solms., Hymenachne amplexicaulis (Rudge) Nees and Luziola subintegra Swallen obtained the highest relative importance values. The most abundant species in all environments and throughout the year was Salvinia auriculata Aubl. Brief comments on the limited use of these aquatic plants are given. [ABSTRACT FROM AUTHOR]

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The Neuro Fuzzy System (NFS) is a hybrid algorithm that combines fuzzy logic with neural networks. Since it can be used as a pattern recognition technique, we explore its potential to characterize the major lithological units encompassed by the first 512 m of the Colombian stratigraphic well Saltarin 1A (Guayabo and León Formations). Thus, we employ the NFS to infer the magnetic remanence S-ratio using bulk magnetic susceptibility (κ), κ-normalized saturation isothermal magnetization (SIRM κ) and/or volume of shale (V sh) obtained from a gamma-ray log. The best results in terms of their corresponding Root Mean-Square Error (RMSE) values, throughout most of the upper Guayabo Formation, where magnetite seems to be an important magnetic phase, are attained with logκ and SIRM κ as input variables. Beyond 350 m downcore, the quality of the inference decreases over the León Formation, characterized by a significant presence of pyrrhotite. However, the extra input variable V sh adjusts the inferred S-ratio to their experimental counterparts throughout this formation suggesting that the early diagenesis process that led to the formation of dispersed clay in these samples was also responsible for the formation of pyrrhotite. Hence the inclusion of manifold input data increases the ability of the net to predict S-ratio in complex geological settings with a sequence of changing lithologies, varying amounts and types of magnetic minerals, and different distributions of mineral grain sizes. In case these variables do not properly infer the actual S-ratio data, the extent of the different lithostratigraphic units would be still identifiable in some cases by the uneven quality of the correlation observed between inferred and experimental values. [ABSTRACT FROM AUTHOR]

Objective. To determine the fecundity and fertility of Macrobrachium amazonicum (freshwater shrimp) of the Piedemonte llanero. Materials and methods. The animals were caught at a fish farm, in the municipality of Restrepo, Meta, Colombia and transported to the fish station of the Institute of Aquaculture of the University of the Llanos. The body weight (g), and total length (mm) of mature females and the fecundity and fertility (number of eggs and larvae/female, respectively) were determined. The diameter and the length of the eggs were determined to calculate their volume. Results. The fecundity varied from 120 to 549 eggs with an average of 331 ± 93. Regarding fertility, the females showed 287 ± 19 larvae, with an interval between 102 and 703. A highly positive lineal regression (r² between 0.85 and 0.91) was observed between fecundity and fertility, and body weight and total length (p < 0.001). The egg diameter was 750.7 ± 2.9 µm (range: 500 - 1000 µm) and egg length of 974.2 ± 3.6 µm (525-1200 µm). The egg size was 296.2 ± 9.7 µm³. Conclusions. The determination of fecundity and fertility for Macrobrachium amazonicum in the Piedemonte Llanero was lower to the results obtained in other studies; however, the size of the eggs was higher. The results could infer that the species breeds throughout the year and allows easy handling and farming in captivity. [ABSTRACT FROM AUTHOR]

Tomás Ojeda Ojeda`s compilation of documentary evidence and oral testimonies detailing one hundred years of the city’s evolution is an important contribution for scholars who write about Colombian urban history, as well as for those concerned with the regional development of the Llanos. His book is crammed with helpful facts and insights, but the fragmented organization of the material and author’s haphazard use of oral interviews combine to make ir a frustrating as well as an illuminating source.