Andes Of Southern Ecuador Research Articles

A new white-flowered Elleanthus (Orchidaceae: Sobralieae) from the Andes of southern Ecuador and notes on hummingbird pollination of Elleanthus scopula

A new species of Elleanthus from southern Ecuador is described and illustrated here. Elleanthus loxensis is characterized by having ramified stems with coriaceous, plicate leaves and white flowers. Its ecological, morphological, and taxonomic traits are compared with other similar species within the genus and discussed here. Additionally, comments on the pollination of Elleanthus scopula are presented.

Anomalous behaviour of fine-grained transition soils from the San Cayetano Formation (Loja, Ecuador)

Numerous landslides, either natural or produced by excavations in road works, occur in the intramontane Neogene Loja basin (southern Ecuadorian Andes) and can be associated with the clayey silts, low plasticity soils (ML). Thirty-two undisturbed samples from eight sites were tested in laboratory to characterize the stress-strain geotechnical soil response, showing a higher internal friction angle and higher cohesion with respect to the standard ML soil values. A testing profile of a road constructed on these soils has been modeled using finite element methods to calculate both the safety factor and the mechanism of evolution. Anomalous behavior is evidenced when a standard ML soil type is considered in the model, with a higher security factor than the less stable and more susceptible ML soils of Loja basin. Therefore, this contribution may serve as a warning to designers and engineers when constructing new structures on these soils. Additionally, it enables the identification of the most effective test for assessing high susceptibility in ML soils, contributing to the refinement and enhancement of methodological procedures during project execution.

Analysis of Land Use Change and Hydrogeological Parameters in the Andean Semiarid Region of Ecuador

Access to freshwater in developing regions remains a significant concern, particularly in arid and semiarid areas with limited annual precipitation. Groundwater, a vital resource in these regions, faces dual threats—climate change and unsustainable exploitation. This study analyzes changes in land use, vegetation cover, and hydrogeological parameters in Catacocha parish, situated in the southern Ecuadorian Andes region. The methodology incorporates the integration of data from the Paltas Municipality, Ministerio del Ambiente, Agua y Transición Ecológica—MAATE—and Instituto Geográfico Militar—IGM. Utilizing GIS tools, vegetation analysis is combined with a comparative assessment of discharge data spanning from 2000 to 2022. The data from the MAATE and IGM play an instrumental role in evaluating alterations in vegetation cover across the years. The study also examines the characteristic curves of the wells and their coefficient of storage. Additionally, it assesses the role of vegetation in facilitating infiltration and explores the potential relationship with precipitation patterns in the study area. In semiarid regions, prioritizing the management of natural vegetation is essential, either through conservation projects or reforestation plans throughout the year. Moreover, population emigration has revitalized land use, reserving specific areas for conservation. The transformation observed in the wells supplying the parish of Catacocha and its vegetation cover from 2000 to 2022 serves as a demonstration of this change. Discharge data remain essential for monitoring variations in well discharge and ensuring a consistent daily supply of potable water.

TWO ADDITIONAL NEW SPECIES OF ELEUTHERODACTYLUS (LEPTODACTYLIDAE) FROM SOUTHWESTERN COLOMBIA

Two new species of the unistrigatus group of Eleutherodactylus are described from the Andes in southern Colombia. One is known from 1500 to 2600 m in western Caquetá and adjacent Huila—this species is related to E. chloronotus and E. vicarius. The other is known from two localities in northern Depto. de Cauca and appears to be the sister species of E. spinosus, known from the eastern flanks of the Andes in southern Ecuador.

Climate and microhabitat shape the prevalence of endozoochory in the seed rain of tropical montane forests

AbstractEndozoochory, the dispersal of seeds by animal ingestion, is the most dominant mode of seed dispersal in tropical forests and is a key process shaping current and future forest dynamics. However, it remains largely unknown how endozoochory is associated with environmental conditions at regional and local scales. Here, we investigated the effects of elevation, climate, and microhabitat conditions on the proportion of endozoochorous plant species in the seed rain of the tropical Andes of southern Ecuador. Over 1 year, we measured seed rain in 162 seed traps on nine 1‐ha forest plots located at 1000, 2000, and 3000 m a.s.l. We recorded climatic conditions (mean annual temperature and rainfall) in each plot and microhabitat conditions (leaf area index and soil moisture) adjacent to each seed trap. In total, we recorded 331,838 seeds belonging to 323 morphospecies. Overall, the proportion of endozoochorous species in the seed rain decreased with elevation. The relative biomass of endozoochorous species decreased with increasing rainfall, whereas the relative seed richness of endozoochorous species increased with increasing temperature and leaf area index. These findings suggest an interplay between climate factors and microhabitat conditions in shaping the importance of endozoochorous plant species in the seed rain of tropical montane forests. We conclude that changing climatic and microhabitat conditions are likely to cause changes in the dominant dispersal modes of plant communities which may trigger changes in the current and future dynamics of tropical forests.Abstract in Spanish is available with online material.

Perceptions of Climate Adaptation and Mitigation: An Approach from Societies in Southern Ecuadorian Andes

Climate research has steadily identified that public responses to the impacts associated with climate change are locally adjusted. These responses are mostly shaped by the prevailing socio-cultural knowledge systems underpinned by resilience thinking in the face of change and adversity. Despite the increasing scientific and policy attention to peoples’ perceptions of climatic changes and adaptive responses, there is still a lag in the more detailed probing and exploration of the local level demographic profiles related to the perceptions of and attitudes and responses to mitigation and adaptation strategies. This is of particular importance as the research, planning, and action concerning climate change mitigation and adaptation needs to be informed by and implemented within specific place contexts. Based largely on semi-structured interviews and complementary face-to-face questionnaires, this study focuses on southern Ecuador to identify people’s stances on climate change mitigation and adaptation and to investigate further the perceptions of farmers on adaptation. The results indicate a tendency among urban residents towards a pro-mitigation stance. Those with a pro-adaptation stance are mainly the residents of rural areas and farmers. Farmers appeared to be highly adaptive to climatic changes and are led by a self-assessed ability to adapt. Their adaptive responses vary according to the geographical place of residence, type of farmer, and age. The findings offer local level empirical evidence for designing effective adaptation strategies.

Effects of land use change on the functional diversity and composition of mixed species avian flocks in the high tropical Andes of southern Ecuador

One of the greatest threats to biodiversity is land use change. Habitat alteration can have strong impacts on functional diversity, i.e., the range of biological traits within a suite of organisms. Mixed species avian flocks are integral to maintaining both taxonomic and functional diversity in tropical forests as they provide participants with greater foraging efficiency, reduced predation risks, and increased resiliency of species and ecosystems to environmental change. Our aim for this study was to determine the effects of land use change on the taxonomic and functional structures of mixed species avian flocks in and around Cajas National Park, Azuay Province in the tropical Andes of southern Ecuador by comparing non-native vegetation in agricultural plots and forest regenerating from historical use as pastureland to the largest intact primary forest in the region. We found no changes in species richness and diversity or functional richness of flocks across habitats, but we did find significant differences in species composition. Surprisingly, we found higher functional diversity and uniqueness of flocks in regenerating forest with more diverse and structurally complex vegetation, but native and non-native forests were functionally similar. We did, however, find significant differences in the community weighted means of four of five functional traits in different habitat types. Overall, the taxonomic and functional structures of mixed species flocks in this region seem relatively unaffected by land use change, indicating flocking as a beneficial strategy for species with higher sensitivities to disturbance in areas with anthropogenic activities. It is critical to maintain functional diversity in ecosystems, as a greater variety of functional traits and functional redundancy implies an efficient and more resilient ecosystem in the face of environmental change. Mixed species flocks provide membership benefits that may mitigate impacts of disturbance via land use change and thus can be considered essential units for conserving avian biodiversity.

Ecology and distribution of the “Critically Endangered” Blue-throated HillstarOreotrochilus cyanolaemus

SummaryThe Blue-throated HillstarOreotrochilus cyanolaemusis a recently described hummingbird endemic to the southern Andes of Ecuador. This “Critically Endangered” species faces multiple conservation problems; thus, acquiring basic ecological information is a key step for guiding sound and integral conservation actions. We performed a series of expeditions throughout the cordillera Chilla-Tioloma-Fierro Urco to gain new data about its ecology, abundance, breeding, and distribution. From November 2019 to March 2020, we surveyed a total of 161.6 km searching forO. cyanolaemus, and gathered data on encounter rates, microhabitats used, and flower resources used. From November 2020 to January 2021 we studied the breeding ecology of the species. Occurrence records ofO. cyanolaemuswere used to build a species distribution model, based on climatic variables and the normalised difference vegetation index (NDVI). We found that the species is relatively more abundant in the western and central portion of its distribution range. Males were found using more shrubby habitats than females, who used more open habitats. They visited flowers of 11 plant species, withChuquiraga jussieuiandPuyassp. being the most frequently used flowers. Nests were found in caves and rocky walls, and only one out of three active nests was successful. The distribution model indicated that the species has a potential distribution range of 62.7 km2. This manuscript is the first comprehensive evaluation of the ecological requirements of the species, and the information provided has important potential for use as a conservation guide for the species and its habitats.

Influence of ENSO on Droughts and Vegetation in a High Mountain Equatorial Climate Basin

Several studies have assessed droughts and vegetation considering climatic factors, particularly El Niño-Southern Oscillation (ENSO) at different latitudes. However, there are knowledge gaps in the tropical Andes, a region with high spatiotemporal climatic variability. This research analyzed the relationships between droughts, vegetation, and ENSO from 2001–2015. Meteorological drought was analyzed using the Standardized Precipitation Evapotranspiration Index (SPEI) for 1, 3 and 6 months. Normalized Difference Vegetation Index (NDVI) was used to evaluate vegetation, and ENSO indexes were used as climate drivers. The Wavelet coherence method was used to establish time-frequency relationships. This approach was applied in the Machángara river sub-basin in the Southern Ecuadorian Andes. The results showed significant negative correlations during 2009–2013 between the SPEI and NDVI, with the SPEI6 lagging by nine months and a return period of 1.5 years. ENSO–SPEI presented the highest negative correlations during 2009–2014 and a return period of three years, with ENSO leading the relationship for around fourteen months. ENSO-NDVI showed the highest positive correlations during 2004–2008 and a return period of one year, with the ENSO indexes continually delayed by approximately one month. These results could be a benchmark for developing advanced studies for climate hazards.

First report of phoresy by silken fungus beetles on Bombus funebris (Hymenoptera: Apidae: Bombini) in the Southern Andes of Ecuador

First report of phoresy by silken fungus beetles on Bombus funebris (Hymenoptera: Apidae: Bombini) in the Southern Andes of Ecuador

NESTING BIOLOGY OF AN ECUADORIAN ENDEMIC HUMMINGBIRD, THE ENDANGERED VIOLET-THROATED METALTAIL Metallura baroni

Violet-throated Metaltail Metallura baroni is a threatened hummingbird species, endemic to the Andes of southern Ecuador. Details about the reproductive biology of this species are largely unknown. In this manuscript, we describe the nest, eggs, and nestlings"™ development based on nine nests found along with the Cuenca-Molleturo-Naranjal road, in Cajas National Park, in 2019. We document a breeding period from March to May, which corresponds to the rainy season. All nests were found in roadside embankments, and were constructed with mosses, small twigs, rootlets, Polylepis sp. (Rosaceae) bark, and Puya sp. (Bromeliaceae) fibers. In all nests, we found two white oval eggs that were exclusively attended by a female across the breeding period. Hatching to fledging period lasted 28-32 days. Nesting at roadsides can be particularly risky due to a high probability of collision with vehicles; thus, an assessment of the breeding success of M. baroni on nests located at roadsides is a research priority for this species. The information provided here increases the knowledge about the natural history of M. baroni.

High Foraging Fidelity and Plant-Pollinator Network Dominance of Non-native Honeybees (Apis mellifera) in the Ecuadorian Andes.

Pollinator foraging fidelity (i.e., consistent and repeated visitation to a particular plant species or area) is poorly understood for most bee species, but is important information for both the conservation of plant and pollinator species and the ecosystem services they provide to humans. We used plant-pollinator surveys and mark-recapture of floral-visiting Hymenoptera to study the foraging fidelity and species interaction network properties of a plant-pollinator community in the tropical Andes of southern Ecuador. After marking 92 bees visiting six plant taxa along four 100-m transects between July 16th and July 31st of 2019, only honeybees were resighted at a recapture rate of 47.7% (41/86). During our surveys, we observed nine bee and two wasp taxa feeding from the flowers of 10 morphospecies of plants, and we found significantly low network nestedness and significantly high network-level specialization. Specialization (d') was also significant for honeybees and bumblebees and for three plant taxa. Overall, our findings indicated that feral, non-native honeybees in this region dominated the local plant-pollinator network, yet this species is acting as a specialist forager at the individual level. Our results suggest that honeybees may be replacing the pollination services of some native bees and wasps in the region, but more research is needed to determine the effectiveness of honeybee pollination for the local plants.

Elevation and Soil Properties Determine Community Composition, but Not Vascular Plant Richness in Tropical Andean Roadside

Roadsides are common ecosystems worldwide, with specific environmental characteristics and multiple effects on plant diversity. As such, they represent examples of highly dynamic anthropogenic ecosystems. Our objective was to assess patterns of vascular species diversity in response to elevation and soil characteristics on a roadside in the Andean mountains of Ecuador. The study area was located in the southern Ecuadorian Andes, at five elevations ± 400 m a.s.l. (2600, 2200, 1800, 1400 and 1000 m a.s.l.), where we recorded species richness and abundance in transects perpendicular to the road. The effects of elevation and soil characteristics on species abundance and richness were analyzed using generalized linear mixed models (GLMMs), while species composition was assessed with a non-metric multidimensional scaling analysis (NMDS) and its relationship to environmental variables. We used indicator species analyses (ISA) to identify which species significantly characterized specific elevation and soil factors from primary succession for restoration processes at the roadside. Although elevation and soil characteristics do not condition vascular species richness, the composition is more similar at elevations E1 and E2 (2600 m and 2200 m a.s.l.), differing from low elevations E4 and E5 (1400 m and 1000 m a.s.l.), which in turn are more similar to each other, while intermediate elevation E3 is similar to the highest and lowest elevations. Soil variables that limited plant communities were pH, bulk density (gr/cm3), silt (%), and sand (%) contents. The indicator species showed a preference for specific environmental and soil condition requirements associated with the different microhabitats and, thus, can be suggested for potential use in roadside revegetation processes in tropical areas. These results can help decision-makers in the implementation of biodiversity conservation and roadside environmental restoration projects in areas of Andean mountain ecosystems which have been affected by the construction of road infrastructure.

Trait‐based Inference of Ecological Network Assembly: A Conceptual Framework and Methodological Toolbox

Photo 1. Foothill humid forests in the Andes of southern Ecuador. Photo Credit: Eike Lena Neuschulz. Photo 2. The Andean forest near sunset. Photo Credit: Eike Lena Neuschulz. Photo 3. Vegetation diversity in the Andean forest. Photo Credit: Eike Lena Neuschulz. Photo 4. Sharp elevational changes shape biodiversity in the Andes. Photo Credit: Eike Lena Neuschulz. Photo 5. Grey-breasted mountain toucan looking for some fruit. Photo Credit: Matthias Schleuning. These photographs illustrate the article “Trait-based inference of ecological network assembly: a conceptual framework and methodological toolbox” by Emma-Liina Marjakangas, Gabriel Muñoz, Shaun Turney, Jörg Albrecht, Eike Lena Neuschulz, Matthias Schleuning, and Jean-Philippe Lessard published in Ecological Monographs. https://doi.org/10.1002/ecm.1502.

The Good, the Bad, and the Ugly of Urbanization: Response of a Bird Community in the Neotropical Andes

Urbanization constitutes one of the most aggressive drivers of habitat and biodiversity loss worldwide. However, studies focused on determining the response of local biodiversity to urbanization are still scarce, especially in tropical ecosystems. Urban ecosystems are characterized by low biological productivity which in turn leads to a reduction in biodiversity. However, the responses to urbanization should be species dependent. For instance, changes in the availability of resources can favor certain species with specific characteristics. We assessed the effects of the urbanization process on a bird community in a city located in the Tropical Andes of southern Ecuador, a region widely recognized for its diversity and endemism of birds. We selected three independent localities in each of the four levels of the urbanization gradient in the study area (forest, forest-pasture, pasture, and urban). In each locality, we sampled the bird community by visual and auditory surveys along 1 km transects between 2016 and 2017. We recorded a total of 1,257 individuals belonging to 74 bird species. We evaluated if the responses of richness and abundance of birds are dependent on trophic guild and foraging strata. We found a significant decrease in bird species richness and abundance from forest to urban sites. However, the response of birds was dependent on the trophic guild and foraging strata. Granivorous birds showed a positive response associated with the urbanization gradient while insectivorous birds showed a negative response. Insectivorous birds were more abundant in forest sites and decreased in abundance across the urbanization gradient. We found that the proportion of birds using different foraging strata drastically changed along urban gradient. Forest sites exhibited a bird community using a variety of habitats, but the bird community became simpler toward the most urbanized sites. Our findings showed different effects of urbanization on bird communities. The ugly: urbanization leads to a dramatic reduction in the diversity of birds, which is consistent in cities with different characteristics and ecological contexts. On the other hand, the responses of bird guilds to urbanization are species dependent. Some guilds are positively impacted by urbanization and show increases in species richness and abundance while other guilds are negatively impacted.

Páramo to Pasture Conversion in a Mountain Watershed: Effects on Water Quality and Quantity

The typical vegetation cover of the Andes in southern Ecuador is composed of grassland wetland ecosystems. These form the basis of the area's hydrology, regulating water flows and supplying water to the lower regions of the basins. This study focuses on the Rircay River subbasin, where the dynamics of human activities have transformed natural ecosystems to alternative land uses, particularly cattle pastures. My study examines the change from native wet grasslands to introduced grasslands for livestock grazing. The research uses cartographic land use and land cover change data from 1990 to 2015. Subsequently, I evaluate the effect of these changes on river flow. Flow is measured at a control point at the exit of the total area. At this point, specific water quality parameters resulting from livestock contamination are measured and related using nonlinear models. The results are conclusive and indicate a marked decrease in river flows and an increase in the concentration of pollutants due to the increased area occupied by livestock pastures.

Flood Early Warning Systems Using Machine Learning Techniques: The Case of the Tomebamba Catchment at the Southern Andes of Ecuador

Worldwide, machine learning (ML) is increasingly being used for developing flood early warning systems (FEWSs). However, previous studies have not focused on establishing a methodology for determining the most efficient ML technique. We assessed FEWSs with three river states, No-alert, Pre-alert and Alert for flooding, for lead times between 1 to 12 h using the most common ML techniques, such as multi-layer perceptron (MLP), logistic regression (LR), K-nearest neighbors (KNN), naive Bayes (NB), and random forest (RF). The Tomebamba catchment in the tropical Andes of Ecuador was selected as a case study. For all lead times, MLP models achieve the highest performance followed by LR, with f1-macro (log-loss) scores of 0.82 (0.09) and 0.46 (0.20) for the 1 h and 12 h cases, respectively. The ranking was highly variable for the remaining ML techniques. According to the g-mean, LR models correctly forecast and show more stability at all states, while the MLP models perform better in the Pre-alert and Alert states. The proposed methodology for selecting the optimal ML technique for a FEWS can be extrapolated to other case studies. Future efforts are recommended to enhance the input data representation and develop communication applications to boost the awareness of society of floods.

Temporal stability in species richness but reordering in species abundances within avian assemblages of a tropical Andes conservation hot spot.

As the pace of environmental change increases, there is an urgent need for quantitative data revealing the temporal dynamics of local communities in tropical areas. Here, we quantify the stability of avian assemblages in the highly threatened, but poorly studied, Andean biodiversity hot spot. We evaluated the temporal variation in species richness and community composition of local bird assemblages in three habitat types (native forest, introduced forest, native shrub) using a unique, relatively long‐term data series from Cajas National Park and Mazán Reserve in the southern Andes of Ecuador. We sampled birds with mist nets using a standardized protocol over 11 years, from 2006 to 2016. Species richness remained stable over time across habitats, but community composition changed in the native forest. In particular, we observed taxonomic reordering in the native forest, in which the evenness in the distribution of abundances of taxa decreased over time. This finding is consistent with other studies where species richness remained constant over time while community composition changed. Our study highlights the value of long‐term studies in the tropical Andes as we show that species composition of birds in a montane forest is changing, consistent with global trends in biodiversity change.

Aposematic Coloration of Moths Decreases Strongly along an Elevational Gradient in the Andes.

Simple SummaryCertain moths defend themselves with toxic substances, and they show this to predators with bright and contrasting coloration. At high elevations, fewer birds, bats and other predators are present that feed on these insects. We therefore expected a decreasing proportion of colorful tiger and lichen moths with increasing elevation. Our study was carried out in forests between 1040 and 2670 m in the Ecuadorian Andes. We scored all 353 observed species according to their warning coloration, and whether they mimic bees and wasps or potentially poisonous beetles. We also measured forewing length of all species. From these data community-weighted means were calculated and related to the elevation of their collection sites. As predicted, the communitywide incidence of all three defensive traits decreased substantially from tall premontane forest to open upper montane forest. In parallel, moth size increased with elevation. Moreover, the systematic composition of tiger and lichen moth assemblages changed substantially. These findings support the idea that different selection regimes favor warning coloration at lower sites with higher predation pressure, while cryptic appearance is more advantageous at higher elevations.On tropical mountains, predation pressure decreases with elevation. Accordingly, one expects an elevational decay in the prevalence of costly defensive traits such as aposematic coloration. Using light-trap catches of Arctiinae moths (353 species, 4466 individuals), assembled along a forested gradient in the megadiverse tropical Andes of southern Ecuador, we show that the incidence of aposematic coloration decreases strongly between 1040 and 2670 m asl. While over 60% of Arctiinae moths were warningly colored at lowest sites, this fraction decreased to less than 20% in montane forest, yet increased slightly again at the highest sites in the very open Purdiaea nutans forest. In parallel, the incidence of hymenopteran mimics and of species that mimic chemically defended beetles decreased with elevation. Hymenopteran mimics accounted for less than 5% of Arctiinae moths at sites above 2100 m, and beetle mimics were essentially lacking at high elevations. These patterns coincide with a change in gross taxonomic composition of Arctiinae ensembles and with an increase in average body size towards higher elevations. Representatives of Euchromiina and Ctenuchina became scarce with altitude, whereas the prevalence of Lithosiinae increased. Our findings suggest that the variable selective pressures along the elevational gradient favor warning coloration primarily at lower sites, whereas cryptic appearance of adult moths dominates in the tropical upper montane forest.

Key plant species to restore plant–hummingbird pollinator communities in the southern Andes of Ecuador

The planning and implementation of restoration in the Tropical Andes have yet to incorporate functional attributes of ecosystems such as pollination. Mutualistic network approaches can be especially useful for this purpose. For example, within networks of hummingbirds and their pollinated plants, most interactions occur on a small number of plant species that are key to conserve and recover pollination functions. To identify such species, centrality metrics derived from network analysis are readily available and can be easily applied. Our study was conducted in the southern Andes of Ecuador in four vegetation types: old‐growth forest, secondary forest, hedgerows, and montane shrub. On each vegetation type, we surveyed hummingbird visitation to plants and constructed plant–hummingbird interaction networks. We calculated a centrality index for each plant species and used this index to describe the individual role of species as either key or peripheral. We also explored how different functional traits of plants, including flower abundance, morphology, and nectar characteristics, were associated with the variation in this index. We found a total of 123 unique pairwise interactions between 44 plant and 15 hummingbird species. Within each vegetation type, we identified 4–11 key plant species. A shrubby life form and abundant flowers were the main traits associated with the key role of species. This study shows a robust protocol to select plant assemblages for the recovery of plant–hummingbird communities.