Andean Forests Research Articles

Morphological and biochemical changes in Quercus humboldtii in response to warmer and polluted urban areas in a tropical Andean city

Abstract The rapid growth of urban population has significantly changed human settlement patterns, leading to a decline in air quality and changes in climatic conditions in urban areas. Trees are recognized as nature-based solutions because they can remove particles from the air and regulate the climate. However, trees are negatively affected by pollution and temperatures, which represent a challenge for urban planning, management, and human health. To assess the impact of urban pollution and warmer climates on functional traits, we conducted a study using Quercus humboldtii, an endangered tree species endemic to Colombia and Panamá that dominates Andean forests and urban green areas in Bogotá. We selected three localities with contrasting pollution levels and climate conditions and measured 10 morphological and biochemical traits in six individuals at each location. Our findings revealed that Q. humboldtii adjusted morphological and biochemical traits in response to the environmental challenges posed by urban environments. The functional strategies varied between individuals with thin and large leaves and acidic pH in the colder and unpolluted native forest, while others displayed a conservative resource strategy (high leaf dry matter content) and neutral pH in the warmer and most polluted locality. Despite these differences, several traits indicate that Q. humboldtii is not a species tolerant to pollution. This is further supported by the air pollution tolerance index (APTI) values. Our results suggest that Q. humboldtii should be planted in areas of Bogotá with low pollution levels in order to promote its long-term survival and support ecosystem services.

Late-Holocene stability and recent changes in small mammal communities in north-central Andean forests of Patagonia

Past and current climatic and environmental changes have contributed to configure actual species distributions and abundances. Knowing their evolution over time allows discrimination between natural and anthropogenic causes in current composition of faunal communities. We evaluate the changes in small mammal assemblages from the north-central Patagonian Andean forests since the Late-Holocene to recent times and their relationship with the environmental modifications driven by human activities. A bone sequence from Población Anticura archaeological site (lower Manso river valley, Río Negro province, Argentina) was studied, which encompasses a time span from the early Late-Holocene (3350 ± 100–2270 ±80 years BP) to final Late-Holocene (1420 ± 70–530 ±50 years BP) and Historical times (480 ± 70–280 ±40 years BP). The species composition indicates that forest environment established in the area from at least the Late-Holocene (dominance of Loxodontomys micropus, with subordinate frequencies of Abrothrix olivacea, A. hirta, Geoxus valdivianus, Irenomys tarsalis, and Paynomys macronyx), with patches of (or near to) open environments (presence of Reithrodon auritus and cavids). It is remarkable the presence of cavids, which increased their abundance in the sequence towards Historical times but disappeared nowadays. The low frequencies (<10%) of the rodent Oligoryzomys longicaudatus along the entire sequence is also relevant, since this rodent is the reservoir of the Andes strain of the Hantavirus (ANDV), which causes pulmonary syndrome. This mouse dominates the small mammal assemblages from forests and ecotonal shrublands of northwestern Patagonia (abundances exceed 50% in owl pellets recently collected from the study area). Current configuration of forest and ecotonal assemblages, particularly the high abundance of O. longicaudatus, should be mainly linked to anthropogenic causes, including the introduction of cattle, land clearing, and the advance of introduced plant species such as the sweet briar ( Rosa eglanteria). Particularly, this exotic shrub offers shelter and additional food for O. longicaudatus, turning their shrublands into spaces of high epidemiological risk.

Humid and cold forest connections in South America between the eastern Andes and the southern Atlantic coast during the LGM

The presence of Andean plant genera in moist forests of the Brazilian Atlantic Coast has been historically hypothesized as the result of cross-continental migrations starting at the eastern Andean flanks. Here we test hypotheses of former connections between the Atlantic and Andean forests by examining distribution patterns of selected cool and moist-adapted plant arboreal taxa present in 54 South American pollen records of the Last Glacial Maximum (LGM), ca. 19–23 cal ka, known to occur in both plant domains. Pollen taxa studied include Araucaria, Drimys, Hedyosmum, Ilex, Myrsine, Podocarpus, Symplocos, Weinmannia, Myrtaceae, Ericaceae and Arecaceae. Past connectivity patterns between these two neotropical regions as well as individual ecological niches during the LGM were explored by cluster analysis of fossil assemblages and modern plant distributions. Additionally, we examined the ecological niche of 137 plant species with shared distributions between the Andes and coastal Brazil. Our results revealed five complex connectivity patterns for South American vegetation linking Andean, Amazonian and Atlantic Forests and one disjunction distribution in southern Chile. This study also provides a better understanding of vegetation cover on the large and shallow South American continental shelf that was exposed due to a global sea level drop.

Indicators sand flies and environment associated to spatial landscaping change in Choco Biosphere Reserve UNESCO.

Sand flies are insects vector associated with terrestrial forest ecosystems; in the Ecuadorian Andes, they participate in the transmission of human cutaneous leishmaniasis. This geographical area is an opportunity to evaluate the role of sand flies as bioindicators od the degree of intervention of a tropical humid forest ecosystems (THF) associated with changes in the ecology of the local landscape. CDC-light traps were used for collecting adults' sand flies in February 2020 in a humid tropical forest within Choco Biosphere Reserve. All species were identified using morphological keys. Analysis data about abundance, richness, species accumulation, diversity index, species composition communities, species sex proportion, spatial sand flies environmental, Renyi's Diversity Profile were performed to compare six spatial habitats in Mashpi locality, Ecuador. Sand flies were collected (n-1435); the main species are represented by Th. reburra Ny. trapidoi, Pa. aclydifera, Py. panamensis and Lu. hartmanni. Only Th. reburra is associated with not intervened forest, while the other 3 species are associated with intervened forest within Mashpi in the Choco Biosphere Reserve. The secondary forest has the major sandflies' richness, while the primary forest exhibits the major abundance. The results indicated that Th. reburra is a sandfly restricted to the Andean Forest and is a bioindicator of the high environmental health quality of the forest, while Ny. trapidoi and Pa. aclydifera are bioindicators of environmental disturbances in the forest. Additionally, Ps. panamensis, Lu. hartmanni and Ny. trapidoi are bioindicators of human impact and the risk of leishmaniasis.

The genus Dryadella (Orchidaceae, Pleurothallidinae) in Brazil

Abstract The present work is a taxonomic revision of the Dryadella species of Brazil. Dryadella comprises 61 species, distributed in humid or seasonally humid forests, from Mexico to southern Brazil, most in the Atlantic Rainforest and the Andean forests. We provide morphological descriptions, taxonomic discussions, illustrations, an identification key, new synonyms, new occurrences and distribution maps for all taxa. Fourteen species are recognised for Brazil, of these D. zebrina recorded also for Bolivia and Peru, D. aviceps in Paraguay, D. lilliputiana in Bolivia, D. gnoma in Ecuador, Peru, Colombia, Panama, and Costa Rica and recorded for the first time in Brazil. The others are endemic to the country and, with the exception of D. gnoma, which occurs in the Amazon and D. ana-paulae, which occurs in the Cerrado, the other species are restricted to the Atlantic Rainforest. We propose the synonymisation of D. osmariniana and D. cardosoi in D. gnoma, D. espirito-santensis, D. gomes-ferreirae and D. litoralis in D. aviceps, D. vasquezii in D. ana-paulae and D. xaveriana in D. toscanoi. Nine lectotypes are designed.

Water quality assessment using biological indicators in Cane River - Colombia

This study shows the results of a water quality assessment for the Basin of the Cane River, which belongs to Iguaque Flora and Fauna Sanctuary National Natural Park, a naturally protected area formed by the Andean Forest and paramo ecosystems in Colombia. The water quality of this river is impacted by agricultural runoff and domestic wastewater from human activities in the buffer area. This was assessed by using chemical, physical, and biological indexes. The IDEAM, NSF and water quality indexes were based on the European standards of measurement. Further to this, BMPW/Col and ETP biological indexes were analyzed and, amongst these, IDEAM WQI (Water quality index) and ETP showed a good correlation. A similar trend was found between the IDEAM water quality index and BMWP/Col index, showing their potential as a good tool for water catchment, diagnosis, assessment, and management in Andean paramo basins. In total, 537 specimens of macroinvertebrates were collected, identifying 8 taxonomic orders, 16 families and 18 genera. Predominant orders were Trichoptera, Ephemeroptera, and Diptera. Baetidae and Planariidae taxas were found in the three water quality levels, showing a decrease in number with a decrease in water quality. Thus, both species have shown sensibility to water quality parameters and also to riverine habitat quality, being then interesting species to determine water quality, deserving more detailed studies for similar cases in high Andean forests and paramo basins.

A neotropical perspective on the uniqueness of the Holocene among interglacials

Understanding how tropical systems have responded to large-scale climate change, such as glacial-interglacial oscillations, and how human impacts have altered those responses is key to current and future ecology. A sedimentary record recovered from Lake Junín, in the Peruvian Andes (4085 m elevation) spans the last 670,000 years and represents the longest continuous and empirically-dated record of tropical vegetation change to date. Spanning seven glacial-interglacial oscillations, fossil pollen and charcoal recovered from the core showed the general dominance of grasslands, although during the warmest times some Andean forest trees grew above their modern limits near the lake. Fire was very rare until the last 12,000 years, when humans were in the landscape. Here we show that, due to human activity, our present interglacial, the Holocene, has a distinctive vegetation composition and ecological trajectory compared with six previous interglacials. Our data reinforce the view that modern vegetation assemblages of high Andean grasslands and the presence of a defined tree line are aspects of a human-modified landscape.

Strategic Incorporation of Experiential Learning in Sustainability Through the Project “Path to A Sustainable Country”

Path to a Sustainable Country (in Spanish “Ruta País Sostenible”) is an institutional commitment that seeks to reinforce the importance of natural resources in the university community and promote learning based on experience. We make field trips around the country that connect nature and communities. The areas selected are the National Natural Parks (NNP) and the protected areas of Colombia (12% of the country's territory). This project has the intention to be closer to the territory´s realities. At the same time, we have an experiential analysis to develop academic projects that promote the conservation of ecosystem services, and the improvement of the quality of life of the surrounding communities. Since 2022, we have made three field trips to the NNP: Chingaza (paramo), Bahía Málaga (mangrove), Desierto de la Tatacoa (tropical dry forest), El Zoque (andean forest), El Cocuy (Glacier). On those trips, we have had 150 participants among students, professors, staff, and alumni. We tested the most appropriate and effective sustainable learning process. The result indicated that 50% of people memorize the concepts when they directly observe nature and communities. Meanwhile, the second most successful tool was applied research (20%), followed by classes (16%), and finally, laboratory practices (14%).

Unraveling plant-pollinator interactions from a south-west Andean forest in Colombia.

Loss of biological connectivity increases the vulnerability of ecological dynamics, thereby affecting processes such as pollination. Therefore, it is important to understand the roles of the actors that participate in these interaction networks. Nonetheless, there is a significant oversight regarding the main actors in the pollination networks within the highly biodiverse forests of Colombia. Hence, the present study aims to evaluate the interaction patterns of a network of potential pollinators that inhabit an Andean Forest in Totoró, Cauca, Colombia. The interactions between plants and potential pollinators were recorded through direct observation in 10 transects during six field trips conducted over the course of one year. Subsequently, an interaction matrix was developed, and network metrics such as connectance, specialization, nestedness, and asymmetry of interaction strength were evaluated by applying null models. An interpolation/extrapolation curve was calculated in order to assess the representativeness of the sample. Finally, the key species of the network were identified by considering degree (k), centrality, and betweenness centrality. A total of 53 plant species and 52 potential pollinator species (including insects and birds) were recorded, with a sample coverage of 88.5%. Connectance (C = 0.19) and specialization (H2' = 0.19) were low, indicating a generalist network. Freziera canescens, Gaiadendron punctatum, Persea mutisii, Bombus rubicundus, Heliangelus exortis, Chironomus sp., and Metallura tyrianthina were identified as the key species that contribute to a more cohesive network structure. The present study characterized the structure of the plant-pollinator network in a highly diverse Andean forest in Colombia. It is evident that insects are the largest group of pollinators; however, it is interesting to note that birds form a different module that specializes in pollinating a specific group of plants. On the other hand, the diversity and generality of the species found suggest that the network may be robust against chains of extinction. Nevertheless, the presence of certain introduced species, such as Apis mellifera, and the rapid changes in vegetation cover may affect the dynamics of this mutualistic network. So, it is imperative to apply restoration and conservation strategies to these ecosystems in order to enhance plant-animal interactions and prevent the loss of taxonomical and functional diversity.

Wood density is related to aboveground biomass and productivity along a successional gradient in upper Andean tropical forests.

Wood density (WD) is a key functional trait related to ecological strategies and ecosystem carbon dynamics. Despite its importance, there is a considerable lack of information on WD in tropical Andean forests, particularly regarding its relationship with forest succession and ecosystem carbon cycling. Here, we quantified WD in 86 upper Andean tree and shrub species in central Colombia, with the aim of determining how WD changes with forest succession and how it is related to productivity. We hypothesized that WD will increase with succession because early successional forests will be colonized by acquisitive species, which typically have low WD, while the shaded understory of older forests should favor higher WD. We measured WD in 481 individuals from 27 shrub and 59 tree species, and quantified aboveground biomass (AGB), canopy height, net primary production (NPP) and species composition and abundance in 14, 400-m2, permanent plots. Mean WD was 0.513 ± 0.114 (g/cm3), with a range between 0.068 and 0.718 (g/cm3). Shrubs had, on average, higher WD (0.552 ± 0.095 g/cm3) than trees (0.488 ± 0.104 g/cm3). Community weighted mean WD (CWMwd) decreased with succession (measured as mean canopy height, AGB, and basal area); CWMwd also decreased with aboveground NPP and stem growth. In contrast, the percentage of NPP attributed to litter and the percent of shrubs in plots increased with CWMwd. Thus, our hypothesis was not supported because early successional forests had higher CWMwd than late successional forests. This was related to a high proportion of shrubs (with high WD) early in succession, which could be a consequence of: 1) a low seed availability of trees due to intense land use in the landscape and/or 2) harsh abiotic conditions early in succession that filter out trees. Forest with high CWMwd had a high %NPP attributed to litter because they were dominated by shrubs, which gain little biomass in their trunks. Our findings highlight the links between WD, succession and carbon cycling (biomass and productivity) in this biodiversity hotspot. Thus, WD is an important trait that can be used to understand upper Andean forest recovery and improve forest restoration and management practices.

Temporal shifts in the functional composition of Andean forests at different elevations are driven by climate change

AbstractAimAndean forests are a global biodiversity hotspot. They harbour many species living within narrow climate ranges and a high functional diversity of trees. It remains still unclear how such hotspots respond to climatic changes over time. We investigated whether Andean forests are changing their functional composition over time along an elevational gradient by assessing changes in species composition, abundance and functional traits.LocationAn elevational gradient in Colombia's northern Andes.Time PeriodSpecies composition changes were studied two to four times from 2006 to 2017, and functional composition from 2016 to 2017.Major Taxa StudiedA total of 1104 tropical tree species with in situ traits characterization.MethodsWe used seven morphological leaf traits and wood density values to analyse the functional trait dynamic over 10 years along an elevational gradient. By analysing changes in species composition, abundance and trait representation, we inferred the magnitude and direction of changes in functional composition. Then, we assessed if the functional change was related to climate change and demography.ResultsWith increased minimum temperature and vapour‐pressure deficit, we found a decrease over time in mean values for leaf area and specific leaf area and increases in leaf thickness and leaf dry matter content. Long‐term temperature increases are smaller with increasing elevation, but the magnitude of trait changes is greater than in lowlands.Main ConclusionsThe functional composition is changing towards more conservative strategies over time across the elevation gradient, with the strongest changes observed at the highest elevations. This pattern is explained by the change in species turnover within communities due to higher recruitment rates of species with high leaf dry matter content values and low leaf area values. These shifts may be related to communities' responses to higher evapotranspiration demand and thermal stress, mainly at higher elevations.

Obsidian on the Island: First Geochemical Characterization for Isla Victoria, Nahuel Huapi National Park (Patagonia, Argentina)

Abstract We present the first geochemical data of archaeological obsidian for Isla Victoria, Nahuel Huapi National Park in Patagonia. XRF analyses were performed on 15 samples of obsidian-like rocks from the Puerto Tranquilo 1 site. Only five of the artifacts—all of which come from upper levels of the site—correspond to obsidian as a raw material. The provenance analysis indicates the use of obsidian sources located in the Andean Forest area of southern Neuquen Province. Based on these preliminary results, we propose a north–south circulation axis for this raw material. These geographic results are discussed in relation to the information available regionally.

NEW SPECIES OF FROGS (ELEUTHERODACTYLUS: LEPTODACTYLIDAE) FROM THE CORDILLERA ORIENTAL OF NORTE DE SANTANDER AND SANTANDER, COLOMBIA

Three additional species of Eleutherodactylus are described from the Andean forests of the northern Cordillera Oriental. One belongs to the E. conspicillatus species group and appears to be related to the widespread E. wiligrum. Another resembles E. tubernasus in appearance but is related to other frogs found in the Central and Occidental cordilleras. The E. tubernasus species group is re-evaluated, reducing the four once-recognized species to two, which are not closely related. The third new species seems to have a connection to E. ga110110/us (Andean forests of eastern Ecuador) and E. viridis (northern part of the Cordillera Occidental).

A new species of Iochroma Benth. (Solanaceae) from the eastern Andes of Colombia.

Iochromaorozcoae A.Orejuela & S.D.Sm., sp. nov. (Solanaceae) is described from the Andean forests of Cundinamarca in the eastern cordillera of Colombia. Iochromaorozcoae was first collected by the eminent Spanish priest and botanist José Celestino Mutis in the late part of the 18th century, but the specimens have lain unrecognised in herbaria for over 200 years. The species shares many features with its closest relative, Iochromabaumii S.D.Sm. & S.Leiva, but it differs from it in having small flowers with five corolla lobes and few inflorescences per branch, located near the shoot apex with 1 to 4 (-8) flowers, fruits that are greenish-yellow when ripe and its restricted geographic distribution. A description of I.orozcoae is provided, along with a detailed illustration, photographs of live plants, a comparison with closely-related species and a key to all Colombian species of Iochroma Benth. In closing, we emphasise the value of historical collections for the knowledge of biodiversity.

Life histories and extraction impacts models in two untapped Geonoma palms

The sustainable management of wild useful palms is crucial for their long-term survival. To understand how populations respond to extraction, it is necessary to examine the impacts of extraction in relation to their life histories in their habitat. A suitable genus for studying extraction responses and understanding life histories is Geonoma, as it exhibits a variety of demographic strategies, has a high potential for use, and some species are considered as untapped sources. Two species, Geonoma orbignyana and G. undata, are used as ornamentals for domestic purposes and commercialized in small-scale markets. They differ in their habitats, with G. orbignyana found in the understory and G. undata in more open spaces, suggesting different life histories. Therefore, the main objective of this study was to simulate the impacts of extraction for ornamental purposes in G. orbignyana and G. undata and identify the relationship with their life histories. The research was conducted in the Andean Forest of Chicaque Natural Park, Colombia in 2019–2021. We determined the demography of the two species, using Integral Projection Models (IPMs), and simulated the extraction of juveniles, leaves, and fruits. We found that both species exhibited typical understory palm patterns in terms of survival and growth rates. However, G. orbignyana had lower maximum individual size and onset of fecundity, indicating understory strategies, while G. undata displayed mixed strategies. The population of G. undata declined during both census periods due to high elasticities on juveniles, and extracting of juveniles is unsustainable, contrary of extraction of fruits and leaves, that seems to be sustainable under certain scenarios. Similarly, the extraction of leaves and fruits in G. orbignyana is potentially sustainable if occurring on specific sizes and rates, but the extraction of juveniles depletes the population. These findings suggest that sustainable extraction practices can be implemented to untapped palm populations while ensuring their conservation. To achieve this, it is crucial to protect the sizes and processes related to the growth and survival of acaulescent juveniles. Only after ensuring their growth should any extraction activities be considered. By adopting these practices, we can promote the responsible use of palm resources and safeguard their long-term viability.

Brief windows with more favorable atmospheric conditions explain patterns of Polylepis reticulata tree water use in a high-altitude Andean forest.

Polylepis trees occur throughout the Andean mountain region, and it is the tree genus that grows at the highest elevation worldwide. In the humid Andes where moisture is rarely limiting, Polylepis trees must adapt to extreme environmental conditions, especially rapid fluctuations in temperature, ultraviolet radiation and vapor pressure deficit (VPD). However, Polylepis' water-use patterns remain largely unknown despite the importance of understanding their response to microclimate variation to determine their capacity to maintain resilience under future environmental change. We conducted a study in a Polylepis reticulata Kunth forest in the Ecuadorian Andes to evaluate its tree water-use dynamics and to identify the main environmental drivers of transpiration. Tree sap flow was monitored simultaneously with soil volumetric water content (VWC) and microclimate during 2 years for trees growing in forest edge and interior locations. We found that sap flow was primarily controlled by VPD and that VWC exerted a secondary role in driving sap flow dynamics. The highest values for sap flow rates were found when VPD>0.15kPa and VCW<0.73cm3cm-3, but these threshold conditions only occurred during brief periods of time and were only found in 11% of our measurements. Moreover, these brief windows of more favorable conditions occurred more frequently in forest edge compared with forest interior locations, resulting in edge trees maintaining 46% higher sap flow compared with interior trees. Our results also suggest that P. reticulata has a low stomatal control of transpiration, as the sap flow did not decline with increasing VPD. This research provides valuable information about the potential impacts of projected future increases in VPD due to climate change on P. reticulata water-use dynamics, which include higher sap flow rates leading to greater transpirational water loss due to this species' poor stomatal control.

A new species of Tournefortiopsis (Guettardeae, Rubiaceae) from northern Colombia

A new species of Tournefortiopsis from high Andean forests of the Central Colombian Cordillera is described and illustrated. Tournefortiopsis triflora is characterized mainly by its dichasium inflorescence, a feature not previously reported in the genus. It can be distinguished from its related species by its smaller leaves, peduncles, and corolla tube, and by the leaves abaxially glabrous on the areoles. The new species is from an area of biogeographic interest due to the large number of endemic species known to this area. A distribution map, conservation status and taxonomic affinities are provided in this paper.

A new species of Tillandsia (Tillandsioidae, Bromeliaceae) from the high Andean forests near Bogotá (Colombia)

A new species of Tillandsia from high elevation forests of the Eastern Cordillera of Colombia is described here: Tillandsia chingacensis. This species is unique because of its floral parts densely covered with a resin-like substance, and exceptionally long fruits. Although this species has distichous flowers and bears petal appendages, it was not placed in Vriesea because it shows morphological affinities to species of Tillandsia subg. Allardtia, suggesting a better placement of this taxon in Tillandsia. The discovery of this species is the result of recent explorations to a former war zone in the proximity of Bogotá (Colombia). This novelty demonstrates that further scientific expeditions to these areas recently opened for exploration will bring numerous taxonomic discoveries for Colombia. Finally, the description of this new species is complemented with notes on its geographical distribution, habitat, conservation status and a discussion of its taxonomic affinities.

Differential effect of dehydration on the voluntary activity of a diurnal toad

Anuran amphibians' ability to maintain their activity at high temperatures or low humidity depends on their capacity to face dehydration, especially when they display diurnal and terrestrial life habits. Melanophryniscus rubriventris is a diurnal and terrestrial toad from humid Yungas Andean forests that breeds in temporary ponds. It is exposed to the recurrent risk of dehydration because of pond desiccations during the breeding season. Here, we study how M. rubriventris males behaviorally respond to dehydration by measuring their voluntary activity under an ex-situ experiment. Toads with different hydration levels were exposed to a circular track for voluntary activity measurements. Dehydrated males of M. rubriventris toads did not adopt a water-conserving posture staying active during the test and increasing walking under severe dehydration. Certain tolerance to dehydration would allow performing daily activities under challenging diurnal conditions. The increased walking under severe dehydration suggests water or shelter-seeking behavior that would be crucial for diurnal and terrestrial toads to overcome the unpredictable hydric environment during the breeding season.

Soil bacteria and fungi communities are shaped by elevation influences in Colombian forest and páramo natural ecosystems.

The influence of elevation on natural terrestrial ecosystems determines the arrangements of microbial communities in soils to be associated with biotic and abiotic factors. To evaluate changes of fungi and bacteria at the community level along an elevational gradient (between 1000 and 3800 m.a.s.l.), physicochemical measurements of soils, taxonomic identifications of plants, and metabarcoding sequences of the 16S rRNA gene for bacteria and the ITS1 region for fungi were obtained. The bacterial taxonomic composition showed that Acidobacteriota increased in abundance with elevation, while Actinobacteriota and Verrucomicrobiota decreased. Furthermore, Firmicutes and Proteobacteria maintained maximum levels of abundance at intermediate elevations (1200 and 2400 m.a.s.l.). In fungi, Ascomycota was more abundant at higher elevations, Basidiomycota tended to dominate at lower elevations, and Mortierellomycota had a greater presence at intermediate sites. These results correlated with the edaphic parameters of decreasing pH and increasing organic carbon and available nitrogen with elevation. In addition, the Shannon index found a greater diversity in bacteria than fungi, but both showed a unimodal pattern with maximum values in the Andean Forest at 2400 m.a.s.l. Through the microbial characterization of the ecosystems, the elevational gradient, soil properties, and vegetation were found to exert significant effects on microbial communities and alpha diversity indices. We conclude that the most abundant soil microorganisms at the sampling points differed in abundance and diversity according to the variations in factors influencing ecological communities.