inter-Andean Valleys Research Articles

Inoculation with Azospirillum brasilense as a Strategy to Reduce Nitrogen Fertilization in Cultivating Purple Maize (Zea mays L.) in the Inter-Andean Valleys of Peru.

Purple maize has gained global significance due to its numerous nutraceutical benefits. However, sustaining its production typically requires high doses of nitrogen fertilizers, which, when applied in excess, can contaminate vital resources such as soil and water. Inoculation with nitrogen-fixing microorganisms, such as those from the Azospirillum genus, has emerged as an alternative to partially or fully replace nitrogen fertilizers. This study aimed to evaluate the inoculation effect with A. brasilense and varying nitrogen fertilization levels on the yield and quality of purple maize. The experiment was carried out using a randomized complete block design (RCBD) with a 2 × 5 factorial arrangement and five replications. Treatments comprised two inoculation levels (control without inoculation and inoculation with A. brasilense) under five nitrogen doses (0, 30, 60, 90, and 120 kg∙ha-1, applied as urea). Inoculation with A. brasilense resulted in a 10.5% increase in plant height, a 16.7% increase in root length, a 21.3% increase in aboveground fresh biomass, a 30.1% increase in root fresh biomass, and a 27.7% increase in leaf nitrogen concentration compared to the non-inoculated control. Regarding yield, the inoculated plants surpassed the control in both purple maize yield (kg∙ha-1) and cob weight by 21.8% and 11.6%, respectively. Across all fertilization levels and parameters assessed, the inoculated treatments outperformed the control. Furthermore, for parameters, namely plant height, leaf nitrogen content, and cob dimensions (length, diameter, and weight), the A. brasilense inoculation treatment with 90 kg N∙ha-1 was statistically equivalent or superior to the non-inoculated control with 120 kg N∙ha-1. These results indicate that inoculation with A. brasilense positively impacted purple maize at all nitrogen levels tested and improved nitrogen use efficiency, enabling a reduction of 30 kg N∙ha-1 without compromising performance in key parameters.

Natural and anthropogenic factors influence flowering synchrony and reproduction of a dominant plant in an inter-Andean scrub.

Agriculture expansion, livestock, and global change have transformed biological communities and altered, through aerosols and direct deposition, N:P balance in soils of inter-Andean valleys, potentially affecting flowering phenology of many species and thereby flowering synchrony and plant reproduction. We evaluated the influence of variation in temperature and moisture along the local elevational gradient and treatments with the addition of N and P and grazing on flowering synchrony and reproduction of Croton, a dominant shrub of the inter-Andean dry scrub. Along the elevational gradient (300 m difference between the lowest and highest site), we set up plots with and without grazing nested with four nutrient treatments: control and addition of N or P alone or combined N + P. We recorded the number of female and male flowers in bloom monthly from September 2017 to August 2019 to calculate flowering synchrony. We assessed fruiting, seed mass, and pre-dispersal seed predation. Higher growing-season soil temperatures, which were negatively associated with local elevation and higher nitrogen availability promoted flowering synchrony of Croton, particularly among larger plants. Greater flowering synchrony, high soil temperatures, and addition of N + P resulted in production of more fruits of Croton, but also intensified pre-dispersal seed predation. Temperature, availability of moisture throughout the elevational gradient, and nutrient manipulation affected flowering synchrony, which subsequently affected production of fruits in Croton. These results emphasize the critical role of current anthropogenic changes in climate and nutrient availability on flowering synchrony and reproduction of Croton, a dominant plant of the inter-Andean scrub.

Small-scale geographic factors promote a high diversity of amphibians and reptiles in Colombia

Analysing spatial biodiversity patterns in amphibians and reptiles is key to understanding the main drivers of community ecological structure, biogeography, and guiding conservation strategies. Our goal is to map patterns of taxonomic change and unravel the geographic and environmental factors driving species turnover among the biomes found in the Sogamoso river basin (SRB), which tributes to the inter-Andean middle Magdalena valley in Colombia, a hyperdiverse region at high-risk from human activities. The study area encompasses lowland forest, submontane, montane and high-elevation Andean habitats, with distinct biomes defined by elevation and physiographic characteristics. To do this, we compared species richness among different biomes and describe their variation along the altitudinal gradient. We collected data from literature and revision of specimens deposited in herpetological collections. Species distribution models were used to estimate geographic ranges and species composition was analysed among biomes using a presence/absence matrix. Generalised Dissimilarity Modelling (GDM) was employed to explore spatial turnover patterns of species composition. We observed that species richness of both amphibians and reptiles was the highest in the tropical humid forest biome and the lowest occurred mainly in the Sub-Andean semiarid vegetation. The spatial pattern of species turnover was the same for amphibians and reptiles and revealed an extreme similarity with the previous delimitation of the five biomes, which are supported by a combination of biotic, abiotic and anthropogenic factors. This study provides valuable baseline information for the conservation of amphibians and reptiles in the SRB and highlights the importance of considering geographic and environmental factors in understanding species distribution and turnover in the region. Keywords: Sogamoso River, herpetofauna, richness patterns, turnover species, ecological structure

Internal deformation of the North Andean Sliver in Ecuador-southern Colombia observed by InSAR

Summary In the Northern Andes, partitioning of oblique subduction of the Nazca plate beneath the South American continent induces a northeastward motion of the North Andean Sliver. The strain resulting from this motion is absorbed by crustal faults, which have produced magnitude 7 + earthquakes historically in the Andean Cordillera of Ecuador and southern Colombia. In order to quantify the strain in that area, we derive a high-resolution surface velocity map using InSAR time-series processing. We analyzed 6 to 8 years of Sentinel-1 data and combined different satellite line-of-sight directions to produce a reliable velocity map in the East direction. We use interpolated GNSS data to express the velocity map with respect to Stable South America and remove the long-wavelength pattern due to the post-seismic deformation following the 2016 Mw 7.8 Pedernales earthquake. The InSAR velocity map finds high E-W shortening strain rates along N-S trending structures within the Western Cordillera and the Interandean valley, with little deformation taking place east of them. This result strengthens the previous proposition of a ∼350 km long Quito-Latacunga tectonic block, forming a restraining bend in the overall right-lateral strike-slip fault system accommodating the northeastward escape motion of the North Andean Sliver. However, the high spatial resolution provided by InSAR indicates that previously proposed boundaries for this block need to be revised. In particular, InSAR results highlight high strain rate (>300 nstrain/yr) along undescribed active structures, south and west of the proposed limits for the Quito-Latacunga block, respectively in Peltetec and Ibarra regions. Interestingly, the two areas with the largest strain rates spatially correlate with the proposed areas of large historical earthquakes. Modeling of the InSAR and GNSS velocities in these areas suggests shallow coupling and high slip rates on structures which, previously, were not identified as active. We also demonstrate a slow-down of the shallow aseismic slip on the Quito fault after the Pedernales earthquake, suggesting that stress changes following large megathrust events might trigger transient slip behaviors on crustal faults. The high-resolution strain map provided by this work provides a new basis for future tectonic models in the Ecuadorian and southern Colombian Andes, and will contribute to the seismic hazard assessment in this highly populated area of the Andes.

Sleeping site sharing between Aotus griseimembra (Mammalia, Primates) and Coendou quichua (Mammalia, Rodentia) in a lowland inter-Andean valley in Colombia

Sleeping site sharing between Aotus griseimembra (Mammalia, Primates) and Coendou quichua (Mammalia, Rodentia) in a lowland inter-Andean valley in Colombia

New distribution records, morphology and natural history notes of the endemic Colombian lizard Anolis limon

Anolis limon is a species endemic to the inter-Andean valley of the Magdalena River, Colombia. We report three new localities for A. limon in the department of Tolima, Colombia, and provide data on its morphology, natural history and behaviour. Specimens were collected during field surveys of the eastern slope of the Central Cordillera in the Colombian Andes and their external features (scales) and internal characteristics (hemipenes) were compared with literature descriptions. We detected some variation in body size and meristic data between populations of A. limon. Furthermore, the distribution of A. limon was limited to the eastern slope of the Central Cordillera, located in the middle of the Magdalena region. This zone is highly fragmented and degraded, which may affect A. limon populations, as other animal species from these localities have disappeared in the last decade. Consequently, an evaluation of the conservation status of A. limon is needed.

Croton maranonensis: a new species of Euphorbiaceae from the tropical inter-Andean dry valleys

We describe Croton maranonensis Riina & Martín-Muñoz sp. nov., a species in Croton section Julocroton (Mart.) G.L.Webster from the seasonally dry tropical forests and shrublands of the inter-Andean valleys. This species is a small shrub occurring along the Marañón river valley in Peru and similar dry areas in southern Ecuador. We surveyed morpho-anatomical characters of the new species and closely related taxa. To confirm the placement of the new species in C. section Julocroton, we conducted a molecular phylogenetic analysis including three accessions of the new species and selected representatives of section Julocroton and related groups within Croton L. Micro- and macro-morphological evidence, and molecular data support C. maranonensis sp. nov. as an independent lineage within the C. section Julocroton clade. We compared the new species with morphologically similar species in the same section that also occur in the Andean region, including C. flavispicatus Rusby, C. triqueter Lam., and C. hondensis (H.Karst.) G.L.Webster.

Variability of Water Use Efficiency of Gmelina arborea Plantations in the Tropical Dry Forest of Colombia

Effective forest management strategies to adapt to climate change are essential. Water use efficiency (WUE), which integrates biomass production and water consumption, is a key indicator of forest adaptation. This study evaluated the WUE of Gmelina arborea plantations in the tropical dry forest and identified the main influencing factors, with implications for silviculture and management. Data on total biomass (TB) and total volume (V) were obtained from permanent sample plots in the upper and lower Magdalena River basin in Colombia. WUE was calculated as m3 of V (WUEV) or kg of TB (WUETB) per m3 of evapotranspired water. Significant regional differences were found, with higher WUE in the Caribbean plains (WUETB = 1 kg m−3 and WUEV = 0.0018 m3 m−3) compared to the inter-Andean valleys (WUETB = 0.77 kg m−3 and WUEV = 0.013 m3 m−3). Stand variables had the greatest influence on WUE, showing positive associations with site productivity and stand density measures. Soil variables such as texture, available water, and calcium content, along with a drier climate, were crucial for achieving higher WUE. The study underscores the importance of comprehensive site selection and effective silvicultural practices to maximize WUE and productivity, especially in the context of climate change.

Phylogenetic placement of Mimosa pabstiana reinforces a biogeographic pattern of the Pleistocene Arc Theory in Mimosa (Leguminosae, Caesalpinoideae)

New molecular evidence derived from the trnD-T region has unveiled an unexpected relationship for Mimosa pabstiana. Traditionally classified within M. sect. Batocaulon ser. Campicolae, our phylogenetic study reveals its new placement within M. sect. Batocaulon ser. Andinae. This discovery aligns with a biogeographic pattern consistent with the Pleistocene Arc Theory, encompassing inter-Andean valleys, the Chaco, Central-West Brazil, and Brazilian seasonally dry forests. Recent observations of M. pabstiana in Brazilian herbaria, along with newly collected field samples documented through photography and georeferencing, bring forth additional data about this poorly-known species. We further elucidate the phylogenetic placement of M. paraibana, previously hypothesized to have a close relationship with M. pabstiana.

Avian haemosporidians of the genera Plasmodium and Haemoproteus from resident and Neotropical migrant birds in Colombia

Avian haemosporidians of the genera Plasmodium and Haemoproteus are a group of widely distributed blood parasites that can negatively affect the fitness of their hosts. Colombia contains the greatest diversity of birds on the planet, but knowledge about the associations between haemosporidian and its avifauna is scarce and fragmented. We collected blood samples from 255 birds (203 residents and 52 neotropical migrants) belonging to 27 families and 108 species. The study was conducted in six localities in the inter-Andean valleys of the Cauca and Magdalena rivers. Parasites of the genera Plasmodium and Haemoproteus were identified in the samples by morphological and molecular analysis of a fragment of the mitochondrial gene cyt b. Among the samples, 9.3% (n = 24) were positive for Plasmodium or Haemoproteus. Co-infection with Plasmodium and Haemoproteus was found in Red-eyed Vireo. Seventeen haemosporidian lineages were identified, five of which were reported for the first time in resident birds (Common Ground Dove, Checker-throated Stipplethroat, Tropical Kingbird, Pale-breasted Thrush, and Ruddy-breasted Seedeater) and one in the Summer Tanager (neotropical migrant). The research results confirm the wide diversity of haemosporidian present in tropical lowlands and the possible role of neotropical migratory birds in dissemination on haemosporidian along their migratory routes.

A new species of Compsoneura (Myristicaceae) from interandean valleys of middle Magdalena and lower Cauca rivers, Colombia

Compsoneura choibo, a new species of Myristicaceae from lowland wet forests located in interandean valleys in middle Magdalena (inhabited by Ateles hybridus) and lower Cauca rivers, Colombia, is described, illustrated, and its morphological relationships with allied species is discussed. This new species is similar to C. mutisii, but it is characterized by the fruits with smooth pericarp but densely covered by T-shaped trichomes. A morphological description, taxonomic comments, an illustration, information about its current conservation status and an updated key to species of Compsoneura are presented. Compsoneura has its center of distribution in Colombia, where 12 of the species are known to occur.

Species distribution models and conservation status of threatened bats in the Tumbesian region of Ecuador and Perú

Introduction: Biodiversity is being lost at an accelerating rate because of global change. Tools such as species distribution models (SDMs) have been widely used to improve knowledge about species’ conservation status and help develop management strategies to mitigate biodiversity loss. SDMs are especially important for species with restricted distributions, such as endemic species. Objective: To determine how potential distribution predicted by SDMs for eight threatened bat species differed from the distribution maps reported by the IUCN. Also, to infer the area of distribution and state of endemism of each specie, and to evaluate the importance of the Tumbesian region for their conservation. Methods: Based on presence records across the species' entire ranges, we used SDMs to assess the conservation status of these eight species in the Tumbesian region of Ecuador and Peru. Results: The areas estimated by SDMs were 35-78 % smaller for four species (Eptesicus innoxius, Lophostoma occidentale, Platalina genovensium and Lonchophylla hesperia) and 26-1 600 % larger for three species (Amorphochilus schnablii, Promops davisoni and Rhogeessa velilla) than those reported by the IUCN. For Tomopeas ravus, the area estimated by the SDM and IUCN was similar but differed in spatial distribution. SDMs coincided with areas of endemism reported by previous authors for E. innoxius, R. velilla, and T. ravus, but were different for A. schnablii, P. genovensium, P. davisoni, and L. hesperia, due in part to projected distributions for these latter species in dry inter-Andean valleys according to the SDMs. Conclusions: The region represents a significant portion (40-96 %) of the predicted distribution of seven of the eight species studied, underscoring the importance of this region for bat conservation. Our results show likely distributions for these species and provide an important basis for identifying research gaps and developing conservation measures for threatened bats in the Tumbes biodiversity hotspot.

Sustainable production strategies to increase the commercialization of tara in Peru

Tara (Caesalpinia spinosa) is a native Peruvian plant that grows in the dry forests of the inter-Andean valleys. It is considered a relevant opportunity for eco-business in the country due to its high efficiency of use and versatility in various industries. This study aims to characterize the production and commercialization of tara by producers located in the Sonche River Valley, in the province of Chachapoyas, in order to provide some opportunities for implementing sustainable tara production strategies to increase its production. The results indicate that tara production activity is being developed in a precarious manner, since production per hectare is below average and there is inefficient use of spaces suitable for cultivation; the production units also have organizational deficiencies such as lack of leverage, little training on sustainability issues and neglect in the harvesting process. These deficiencies are invaluable opportunities to implement strategies such as the practice of sustainable crops, the use of improved varieties, and education, research and development regarding tara production.

Presence of Triatoma breyeri (Reduviidae, Triatominae) in Bolivia.

The study focuses on identifying and understanding the ecological dynamics of Triatoma breyeri in Bolivia. Morphological identification and molecular analysis using gene fragments (COI, CytB and 16S) confirms T. breyeri's presence and its relation to other species. The species has been consistently found in the Estancia-Mataral-La Palma region since 2010 but has not spread to other regions in Bolivia. The region of occurrence is a small characteristic dry inter-Andean valley. A MaxEnt model suggests part of the Bolivian Montane Dry Forest ecoregion serves as a unique habitat within its range. The infrequent presence in Bolivia and the distance from its main range in Argentina suggest recent accidental introduction, possibly through human transport. Further research is needed to comprehend its persistence in this small area of Bolivia.

Notes on the distribution and colouration in life of Stenomacra tungurahuana Brailovsky & Mayorga, 1997 (Hemiptera: Largidae)

The hemipteran Stenomacra tungurahuana Brailovsky & Mayorga, 1997 (Hemiptera, Heteroptera, Largidae) remains known from just two localities in the inter-Andean valley of Ecuador. No ecological information nor description of its colouration in life have been reported. In this contribution, I provide the first record of S. tungurahuana on the northeastern slopes of the Eastern Cordillera of the Andes and the first description of its colouration in life, including photographs, based on a specimen from San Isidro Lodge, province of Napo, ca. 108 km from the species’ type locality.

Subiendo: nuevos registros altitudinales de abejas de las orquídeas (Hymenoptera: Apidae) en los valles interandinos del sur de Ecuador y su potencial ruta de dispersión

Orchid bees are a conspicuous and ecologically important group of insects, commonly distributed at medium and low altitudes in tropical ecosystems. Therefore, new recordings of orchid bees at higher altitudes are interesting. Here we report the presence of two species of orchid bees in urban and peri-urban environments within the inter-Andean valleys in the province of Azuay in southern Ecuador at more than 2,200 m. One male of Eulaema (Apeulaema) polychroma (Mocsáry, 1899) and a female of Euglossa (Euglossa) cf. charapensis Cockerell, 1917, were recorded in the city of Cuenca at 2,550 m, and several females of Eg. (Eg.) cf. charapensis in the surroundings of the city of Gualaceo at 2,264 m. These new altitude distribution records represent the highest for the genus Euglossa in Ecuador. Also, they show the great altitude dispersal capacity, and high adaptability of these insects to urban and peri-urban environments. Finally, we proposed the Jubones river basin as a potential migration route of these bees from lowland areas in the western foothills of the Andes to the inter Anden valleys of Cuenca and Gualaceo.

Myoxanthus anancusiensis (Orchidaceae: Pleurothallidinae), a new species from the inter-Andean valley of Huancavelica, Peru

We report a new species of Myoxanthus from Huancavelica, Peru. Myoxanthus anancusiensis is described, illustrated, and compared with its similar species M. serripetalus and M. oliviae. We carried out a systematic review of the herbarium information of Myoxanthus species reported for Peru and compared the morphological characteristics of similar species, to rule out overlooking already described taxa. The new species is characterized by being a medium-sized plant with a terrestrial habit that grows at an elevation of 2800 m. The flower is cherry-red in color with slightly yellow striations. The sepals present a smooth adaxial surface, and the petals are oblong-caudate with entire margin. The labellum is oblong-elliptic and fimbriate with lateral lobes erect. The new species represents an important record for the flora of the inter-Andean valleys of central Peru in the department of Huancavelica and suggests that carrying out more expeditions in this type of ecosystem is desirable.

Effects of the invasive fish Poecilia reticulata on the behavioral response of Daphnia pulex to the exotic submerged macrophyte Egeria densa

AbstractThe high-elevation plateaus of the inter-Andean valleys are home to shallow lakes that have become eutrophic. These lakes share similarities with shallow lakes in temperate and subtropical areas. Because native species diversity is low, invasive species dominate the fish and macrophytes communities. The study aimed to investigate the behavioral response of the local Daphnia pulex from the Andean shallow Lake Yahuarcocha to the exotic submerged macrophyte Egeria densa and the exotic fish Poecilia reticulata. Laboratory habitat choice experiments revealed that D. pulex from Lake Yahuarcocha strongly avoid E. densa, irrespective of the presence of the fish P. reticulata or chemical cues indicating fish predation on D. pulex. This observation could be explained by the fact that P. reticulata displayed a strong attraction to E. densa during the daytime, probably to avoid bird predation. D. pulex from the nearby Lake San Pablo where P. reticulata is absent but where the fish community is dominated by Oncorhynchus mykiss displayed the same avoidance behavior to submerged macrophytes as D. pulex from Lake Yahuarcocha. These results indicate that macrophytes in these high-elevation shallow lakes may not facilitate top-down control of phytoplankton, since plants do not offer refuge to D. pulex from fish predation.

Conceptual model of groundwater flow in a volcanic-sedimentary aquifer system of the Andean region of Chimborazo, Ecuador

The Chimborazo volcano is located in Ecuador's northern Andes and is one of the world's tallest mountains. The central valley of Riobamba's morphology, structure, and groundwater flow networks are all influenced by the evolution of this stratovolcano. Both the urban and rural populations in this area rely on groundwater extracted from volcano-sedimentary aquifers. This study presents a conceptual model of the groundwater flow system in the lower Chambo River basin (LCRB) based on the interpretation of geological, hydrogeological, hydrochemical, and stable isotope (δ18O and δ2H) data from 23 wells, 10 springs, two sources of surface water, and rainwater. The Tertiary-Quaternary volcanic-sedimentary infill of the Inter-Andean Valley, that overlies the Jurassic-Cretaceous metamorphic bedrock of the Eastern and Western cordilleras, gave rise to three multilayer aquifers (Llo-Guano, Riobamba, and Yaruques). In these aquifers, groundwater flows from the recharge of Chimborazo glaciers to deep circulation zones of low-elevation lands in Riobamba. In this pathway, groundwater evolves from acidic - low temperature - low electric conductivity bicarbonate waters to alkaline - high temperature - high electric conductivity sulfate waters discharged in the Chambo River. The stable isotope data confirmed the hypothesis of different types of water changing and interacting in the flow direction, demonstrating a dynamic hydrogeological system that evolves from the recharge area in Chimborazo, Igualata, and Altar volcanoes to the discharge area in the Chambo River.

CARACTERIZACIÓN DE LAS UNIDADES DE PRODUCCIÓN DE TARWI (Lupinus mutabilis Sweet)

<p><strong>Background.</strong> Tarwi is a legume native to the Andes of South America and is currently an important crop in subsistence agricultural systems because it contributes to the generation of economic income and food security for the rural population.<strong> Objetive</strong>. To characterize the tarwi production units (UPT) in the inter-Andean valleys of the department of Ancash, Peru. <strong>Methodology</strong>. The research was of a descriptive, comparative, correlational, non-experimental type, survey data from 169 UPT were used and the characterization was carried out using statistical techniques of multidimensional analysis. <strong>Implications</strong>. The UPT are small-scale, they are integrated into diversified production systems, which implies knowing their characteristics in order to define coherent development plans or projects to promote the production and consumption of tarwi. <strong>Conclusions</strong>. The UPT are family farming; the family participates in running the plots and in generating economic income both from the main crop, as well as from other complementary sources. The farmers are typified mostly as small-scale, and their production is oriented towards family food security and some surpluses for the market; however, due to the gradual loss of conservation agricultural practices, abandonment of the state in promoting its conservation, cultivation, consumption and lack of financing and technical assistance, the cultivated area of tarwi is gradually decreasing.</p>