Puna Grassland Research Articles

Fire as driver of plant communities and soil properties changes in Puna grasslands in Southern Peruvian Andes

Fire occurrence has been increasing in the high Andean grasslands due to the presence of highly flammable elements and climate change. Understanding the effects of the fires is crucial for the conservation of these ecosystems. This study aimed to determine the effects of fires on the composition, diversity, fruiting of plant species, and physicochemical characteristics of soils in high Andean grasslands over two post-fire growing seasons. We assessed ten fires, five of which occurred in 2023 (one post-fire growing season) and the other five in 2022 (two post-fire growing seasons). Ten transects were established at each study site, five in burned areas and five in unburned areas. Species composition differed between burned and unburned areas across both post-fire growing seasons. Species diversity and evenness were higher in the burned areas compared to unburned areas after two post-fire growing seasons. In both post-fire growing seasons, dry mass was higher in unburned areas than in burned areas. Herbs showed a higher percentage of individuals in the reproductive stage in burned areas, but only after one post-fire growing season. In contrast, the presence of woody individuals with reproductive structures was higher in unburned areas across both post-fire growing seasons. Regarding soils, only some parameters (organic matter, Na+, CEC, pH, available P, and K+) were affected by fires, and the direction of these changes varied between ∼ 6 months and ∼ 18 months post-fires. Our study suggests that fire severity in this type of ecosystem is low, as most soil parameters were not significantly affected. The burning of grasses may lead to increased diversity, particularly due to the enhanced fruiting of herb species. However, the recovery of woody species and biomass requires more time, which is perceived negatively by the local population.

A snow-dwelling tropical butterfly? An unprecedented discovery of a new genus of the Pedaliodes clade in an extreme, high-altitude Andean environment (Lepidoptera: Nymphalidae: Satyrinae)

Abstract A new genus of satyrine butterflies, Nivaliodes gen. nov., is described for three species, all new: Nivaliodes negrobueno sp. nov., Nivaliodes viracocha sp. nov., and Nivaliodes puriq sp. nov. (Lepidoptera: Nymphalidae), with the support of molecular data and adult morphology. A target enrichment-based phylogeny indicates that Nivaliodes gen. nov. is sister to the genus Pherepedaliodes within an extremely diverse Pedaliodes clade of the predominantly Andean subtribe Pronophilina. Although an overwhelming majority of species of this group occur in tropical montane forests, N. negrobueno sp. nov. was discovered in a central Peruvian desert puna at some 4600–4800 m a.s.l., the highest elevation reported for any species of the Pronophilina. Individuals were observed overflying rocky slopes and resting directly on snow-covered surfaces, which is an exceptionally unusual behaviour among butterflies. The other two species of the new genus were found at lower elevations, some 3300–4200 m a.s.l., at the timberline and in puna grassland.

Spatial variation of guanaco (Lama guanicoe) densities influenced by natural and anthropogenic variables in Southern Andean Precordillera (Argentina)

ABSTRACT The spatial distribution of ungulate densities is determined by their decisions on habitat selection, modulated by environmental characteristics and human activities. Poaching and habitat degradation are threats to the guanaco, a native herbivore of arid environments of South America. Seasonal surveys of guanacos were carried out during two independent years in mountain environments of Andean Precordillera, inside a protected area and surroundings. Field surveys and GIS analyses estimated environmental variables. Density surface models estimated spatial distribution of guanacos, based on predictions about food availability, weather, risk perception, and human activities. The current distribution of densities is mainly influenced by the availability of preferred food and water, and protection effectiveness. Twelve years ago, disturbing human activities were also relevant. High densities in great altitudes yearlong, and a winter expansion through lower altitudes, are evidence of partial migrations, related to climatic events and food declines. Selective use of Puna grasslands and association with wetlands agree with food and risk predictions. Greater densities inside than outside the protected area, and decreasing guanaco–observer distances, are evidence of continued effective protection. Density surface modeling, applied to multi-year distance sampling, highlights as a useful tool for understanding the spatial dynamics of guanaco populations, and aiding management decisions.

Implicancias del manejo de una pastura cultivada en secano y la respuesta al abonamiento

The nutrient use in forages livestock system production high Andean is little used. This study evaluated the response of fertilization on the association of cultivated grasses in dry of Dactilys (Dactylis glomerata var. Potomac) and red clover (Trifolium pratense var quiñequeli). The study area was located at 4350 m of altitude in to the Puna ecoregion in Ayaracra sector, Pasco region of Peru. The experimental design was randomized complete block with factorial 2x3x2; with two levels of nitrogen (0 to 50 kg/ha), three levels of phosphorus (0, 80 to 160 kg/ha) and two levels of potassium (0 to 30 kg/ha). Was evaluated were floristic composition, growth rate and pasture production. The results indicate that fertilization nitrogen (50 kg/ha) and phosphorus (80 kg/ha) showed effect a significant the growth rate and forage production. There was not an effect potassium fertilization on the variables evaluated. The analysis of the interactions indicates that the combination of N 50, P 80 and K 0 showed gave better results in forage production than the other treatments.

Diversity and co-occurrence of small and medium sized mammals in rock outcrops of the Desert Puna

ABSTRACT Limited knowledge exists about rock outcrops in Argentina, especially in the Puna ecoregion. This study investigated small and medium-sized mammal diversity using caves and crevices in Desert Puna’s rocky areas. Three rock outcrop sites, >1 km apart at Don Carmelo Reserve, were equipped with five camera traps each. Monitoring spanned 34 days (dry season) and 22 days (wet season). Five mammal species utilized caves and crevices, with 99% sampling coverage in both seasons. The wet season had slightly higher species richness, while the dry season showed higher diversity. Co-occurrence analysis revealed multiple rodent species sharing caves, indicating substantial species sharing and potential interactions in this habitat. These findings enhance our understanding of mammalian communities and the ecological complexities of the Puna ecoregion.

Late Pleistocene human occupations in the southern puna, Chile (12,4–10,7 ka cal. BP): Primary results from the Salar de Infieles (25°S, 3529 m. a.s.l.)

This article presents the results of excavations at the Infieles-1 site, located at 3529 m. a.s.l. in the Salar de Infieles (25°S), highlands of the Chile's southern Puna ecoregion. An initial human occupation was discovered next to an ignimbrite rock-shelter at a depth of 70–80 cm on top of a volcanic ash deposit, dated between 10,798 and 12,440 cal yr BP. The archaeological record consists of lithic wasted-flakes and knapping debris, an ultra-marginal andesite side-scraper, vicuña bone fragments and traces of red mineral pigment. As far as now, this event is the first human occupation recorded in the southern Puna. It is a camp associated with more favourable environmental conditions during the late Central Andean Pluvial Event II (CAPE II).

A new species of Andean frog of the genus Phrynopus (Anura: Strabomantidae) from southeastern Peru.

The Cordillera de los Andes is one of the most important regions for biodiversity. Among amphibians, many endemic species of terrestrial-breeding frogs have recently been discovered. Herein we describe Phrynopus sancristobali from the Andes of southeastern Peru based on molecular and morphological data. The new species is known from the ecotone between humid puna and montane forest at 3910 m a.s.l. on the left side of the Apurímac Valley in the Department of Ayacucho. The new species differs from congeners by having dorsum bearing pustules and light brown with dark brown reticulations surrounding the areolas, and coloration consisting of flanks golden brown with gray or dark brown marks, palms pale orange, soles deep orange, toes IV and V dark brown in dorsal and ventral view, belly cream to yellow with gray to light brown marks, and groin and throat deep orange. The snout-vent length (SVL) is 20.7 and 22.2 in two females, and 19.5 mm in one male. According to our phylogeny inferred using Maximum Likelihood with a concatenated dataset of three mitochondrial and two nuclear genes, P. sancristobali is sister taxon of P. apumantarum, recently described from Department Huancavelica. Our description extends the known geographic range of Phrynopus 73 km to the south, and P. sancristobali is the only species in the genus known to occur south of the Mantaro River, whose deep valley is hypothesized to be a biogeographic barrier for high-Andean organisms. The discovery of P. sancristobali confirms the high levels of endemism and beta diversity of Phrynopus in the moist puna grasslands and montane forests of the high Andes of Peru, and suggests that further work will reveal the presence of additional species in southern Peru.

A new species of frog (Terrarana, Strabomantidae, Phrynopus) from the Peruvian Andean Grasslands

We describe a new terrestrial frog from the puna grasslands adjacent to the Mantaro dry valley in southern Peru. Phrynopus apumantarumsp. nov. is similar in appearence to P. bufoides but is differentiable by lacking discoidal fold and enlarged warts on dorsum, lacking a prominent post ocular fold and having canthal and post ocular stripe. Lastly, we propose to place the new species under the Vulnerable (VU) category of the IUCN Red List, due its small distribution and habitat loss recorded at the type locality.

Modeling the potential distribution of floristic assemblages of high Andean wetlands dominated by Juncaceae and Cyperaceae in the Argentine Puna

Aims: The aim of this work was to model the distribution of suitable environmental conditions of vegas with specific floristic characteristics. Vegas are high Andean wetlands that represent the main sequestered carbon stocks, biodiversity hotspots, and water regulating systems in the region. In these wetlands, plant communities are the main biological factor that determines functional processes, and plant species assemblages are associated with different ecogeographic features. Study area: Argentine Central Andean Puna ecoregion. Methods: For two different floristic assemblages of vegas, we develop ecological niche models of n-dimensional minimum volume ellipsoids through NicheToolBox, then obtain potential distribution maps. One floristic assemblage was dominated by the cushion-structured plant Oxychloe andina (Juncaceae) and the other by plants of the Cyperaceae family. Results: Elevation and precipitation were the main environmental factors determining the distribution of the two floristic assemblages. Juncaceae dominated vegas tend to be located in high, humid, and cold places, while Cyperaceae vegas are found at a lower elevation, with less humidity, and higher temperatures. According to the dominant climatic gradient in the region, potential distribution maps show that vegas of Juncaceae are commonly found towards the Northeast of the Puna while Cyperaceae vegas are more frequent at lower elevations to the South of the region. Conclusions: This study represents the first approach to niche modeling based on plant communities in vegas of the Argentine Puna, providing knowledge on the environmental factors that limit their distribution. This information could serve as a planning tool in a region exposed to growing perturbations such as mining and climate change. Taxonomic reference: Zuloaga et al. (2019). Abbreviations: AUC = Area Under the ROC Curve; NDVI = Normalized Difference Vegetation Index; ROC = Receiver Operating Characteristic.

Modeling geographic distribution of arbuscular mycorrhizal fungi from molecular evidence in soils of Argentinean Puna using a maximum entropy approach.

The biogeographic region of Argentinean Puna mainly extends at elevations higher than 3,000 m within the Andean Plateau and hosts diverse ecological communities highly adapted to extreme aridity and low temperatures. Soils of Puna are typically poorly evolved and geomorphology is shaped by drainage networks, resulting in highly vegetated endorheic basins and hypersaline basins known as salar or salt flats. Local communities rely on soil fertility for agricultural practices and on pastures for livestock rearing. From this perspective, investigating the scarcely explored microbiological diversity of these soils as indicators of ecosystems functioning might help to predict the fragility of these harsh environments. In this study we collected soil samples from 28 points, following a nested design within three different macro-habitats, i.e., Puna grassland, hypersaline salar and family-run crop fields. Total fungi and arbuscular mycorrhizal fungi (AMF) occurrence were analyzed using eDNA sequencing. In addition, the significance of soil salinity and organic matter content as significant predictors of AMF occurrence, was assessed through Generalized Linear Mixed Modeling. We also investigated whether intensive grazing by cattle and lama in Puna grasslands may reduce the presence of AMF in these highly disturbed soils, driving or not major ecological changes, but no consistent results were found, suggesting that more specific experiments and further investigations may address the question more specifically. Finally, to predict the suitability for AMF in the different macro-habitats, Species Distribution Modeling (SDM) was performed within an environmental coherent area comprising both the phytogeographic regions of Puna and Altoandino. We modeled AMF distribution with a maximum entropy approach, including bioclimatic and edaphic predictors and obtaining maps of environmental suitability for AMF within the predicted areas. To assess the impact of farming on AMF occurrence, we set a new series of models excluding the cultivated Chaupi Rodeo samples. Overall, SDM predicted a lower suitability for AMF in hypersaline salar areas, while grassland habitats and a wider temperature seasonality range appear to be factors significantly related to AMF enrichment, suggesting a main role of seasonal dynamics in shaping AMF communities. The highest abundance of AMF was observed in Vicia faba crop fields, while potato fields yielded a very low AMF occurrence. The models excluding the cultivated Chaupi Rodeo samples highlighted that if these cultivated areas had theoretically remained unmanaged habitats of Puna and Altoandino, then large-scale soil features and local bioclimatic constraints would likely support a lower suitability for AMF. Using SDM we evidenced the influence of bioclimatic, edaphic and anthropic predictors in shaping AMF occurrence and highlighted the relevance of considering human activities to accurately predict AMF distribution.

Preferential substrate use decreases priming effects in contrasting treeline soils

Climate change currently manifests in upward and northward shifting treelines, which encompasses changes to the carbon (C) and nitrogen (N) composition of organic inputs to soils. Whether these changed inputs will increase or decrease microbial mineralisation of native soil organic matter remains unknown, making it difficult to estimate how treeline shifts will affect the C balance. Aiming to improve mechanistic understanding of C cycling in regions experiencing treeline shifts, we quantified priming effects in soils of high altitudes (Peruvian Andes) and high latitudes (subarctic Sweden), differentiating landcover types (boreal forest, tropical forest, tundra heath, Puna grassland) and soil horizons (organic, mineral). In a controlled laboratory incubation, soils were amended with substrates of different C:N, composed of an organic C source at a constant ratio of 30% substrate-C to microbial biomass C, combined with different levels of a nutrient solution neutral in pH. Substrate additions elicited both positive and negative priming effects in both ecosystems, independent from substrate C:N. Positive priming prevailed above the treeline in high altitudes and in mineral soils in high latitudes, where consequently climate change-induced treeline shifts and deeper rooting plants may enhance SOM-mineralisation and soil C emissions. However, such C loss may be compensated by negative priming, which dominated in the other soil types and was of larger magnitude than positive priming. In line with other studies, these results indicate a consistent mechanism linking decreased SOM-mineralisation (negative priming) to increased microbial substrate utilisation, suggesting preferential substrate use as a potential tool to support soil C storage.Graphical abstract

Importance of peatlands to maintain avian diversity in the Bolivian High Andes

The High Andean peatlands are peat-accumulating wetlands dominated by cushion-forming plants and are embedded in a matrix of puna grasslands above 4,000 m. These ecosystems are an essential source of water and evergreen vegetation for wild and domestic animals and are considered sensitive to environmental alterations. We studied the birds' habitat and microhabitat preference in peatlands and their surrounding grasslands in the Cordillera Real, Bolivia. We established 3 parallel transects around 12 peatlands: (1) in peatland, (2) at 100–200 m from the peatland edge, considered as the transition habitat between peatlands and grasslands, and (3) in puna grasslands at >500 m from the peatland edge. We quantified bird abundance, species richness, and the availability of 8 microhabitats along 36 transects. We recorded 934 individuals of 34 species and found higher bird species richness and abundance in peatlands than in surrounding grasslands and transition habitats. We found that 26% of bird species were exclusive to peatlands. While most bird species common in peatlands were almost nonexistent in other habitats, most species associated with grasslands were also found in proximity to peatlands. A canonical correspondence analysis showed that bird species were associated with one or more microhabitats. The high abundance, bird species richness, and diet types in peatlands is probably related to the high primary productivity of peatlands and year-round availability of water. Degradation of these peatlands may reduce the abundance of regional bird communities, not only peatland specialists but also species in surrounding habitats.

Floristic types of high‐Andean wetlands from northwest Argentina and their remote‐sensed characterization at a regional scale

AbstractAimsHigh‐Andean vegas are key functional wetlands in the Puna ecoregion. Plant communities in combination with ecogeographic characteristics determine their functional processes. In this study, we identified groups of vegas based on their plant composition and characterized these groups with spatial and spectral variables representing their ecogeographic context.LocationArgentine Puna and High‐Andean ecoregions.MethodsWe recorded the species composition and cover of plants in 50 vegas distributed along a ecogeographic gradient. We calculated six spatial and 14 spectral variables for each vega. We performed a correspondence analysis (CA) to explore species data and used the site's scores in a k‐means analysis to identify groups of vegas. Then, we characterized each group of vegas with spatial and spectral variables with the v.test using the ‘catdes’ function in the FactoMineR package.ResultsThe CA showed five groups of vegas segregated by the plant species composition. Each group was related to different spatial and spectral variables showing an ecogeographic gradient. Vegas with Poaceas were located at higher altitude and lower latitude and longitude (Group 1, Festuca nardifolia and Deschampsia hackelii). Vegas dominated by cushion species had higher humidity (Group 2, Oxychloe andina), and higher and more stable productivity (Group 3, Eleocharis pseudoalbibracteata), while vegas with halophytic species were associated with a larger area, higher salinity, and lower humidity (Group 4, Amphiscirpus nevadensis), and lower productivity (Group 5, Lycium humile and Salicornia pulvinata).ConclusionsOur results are the first floristic classification and remote‐sensing characterization of high‐Andean vegas at a regional scale. This information shows the variation of these ecosystems and suggests that remote sensing, complemented with field information, could help to identify types of vegas at regional scales. This information is relevant for land planning and sustainable management of these key ecosystems in the context of threats of global change.

A new species of Succinea (Gastropoda: Stylommatophora) from the Puna highlands of Argentina

A new species of Succinea Draparnaud, 1801, S. punasp. nov., from the Puna highlands in Catamarca Province, Argentina, is described. Seventeen water bodies were surveyed in the Puna ecoregion of Catamarca, with gastropods being found only at two localities, El Peñón and Guanchín River. We explored the morphological features of shells, reproductive system, radulae, and mandibles of specimens from each site. Although we found slight differences in the shell and the terminal genitalia, with specimens exhibiting an epiphallus folding over itself with terminal globular appearance, whereas others with an epiphallus cylindrical, we conclude that these are intraspecific variabilities. We used DNA sequences of the 16S-rRNA gene to explore genetic distances and genealogical relationships among both populations and other species of Succinea. We found maximum genetic interpopulation distances of up to 2.38%. Mean interspecific divergences among S. punasp. nov. and other Succinea species ranged between 7.14% and 15.21%. A secondary structure model of domains IV and V of the 16S-rRNA gene was developed, with polymorphic sites being concentrated in loop regions. A GIS analysis was carried out using a selection of bioclimatic variables to characterize the environment of the new species in comparison to other close Succinea species from South America. The analysis showed that the particular environmental conditions of the Puna in Catamarca are hardly present in other zones of South America, supporting our hypothesis that S.puna is endemic to that area. The restricted distribution of S. punasp. nov. in a single ecoregion with extreme climatic and physiographic characteristics, high altitude habitat and its microhabitat specialization, makes this species potentially vulnerable to impacts of future anthropogenic changes.

Co-building knowledge on human-puma conflict: A case study in a village of the Argentine Puna ecoregion

ABSTRACT Human-carnivore conflicts threaten the survival of large carnivore populations and impose high costs for humans. Knowledge co-building approaches can be successful for tackling these problems. We examined conflicts between the puma (Puma concolor) and pastoralists from an Argentine Puna village through semi-structured interviews and a focus group discussion. According to data from the community, 6% of livestock were killed by pumas in 2017, causing an estimated US $14,340 loss. Interviewees perceived pumas as dangerous and hunted them to protect livestock. Predation and diseases were identified as major causes of livestock losses, and infrequent checks on livestock, livestock being free-ranging, and an increase in the puma population were underlying causes of predation. Interviewees mentioned direct economic costs and indirect and hidden costs as consequences of livestock loss. Given that social factors are important drivers in human- wildlife conflicts, we highlight the importance of engaging the community during conflict research and management.

Responses of Polylepis birds to patch and landscape attributes in the High Andes

ABSTRACT Habitat loss and fragmentation can devastate biodiversity, especially at regional and global scales. However, generalizing to individual species is challenging given the wide variety of intrinsic and extrinsic factors that shape species-specific responses – particularly among species that are specialists, generalists, or adapted to naturally patchy landscapes. In this study, we examined how patch and landscape attributes affected bird communities within Polylepis forest ecosystems, which are patchily distributed within landscapes of Puna grasslands and shrublands in the High Andes of Peru (3,300–4,700 m). We surveyed birds in 59 Polylepis patches and 47 sites in the Puna matrix, resulting in 13,210 observations of 88 bird species, including 15 species of conservation concern specialized on Polylepis. Data were analysed using Multi-Species Occupancy-Models (MSOM) and cumulative species-area curves. Species richness was generally greatest at mid-to-low elevations, within small fragments, and in landscapes with comparatively little forest cover; this was especially true for birds associated with the Puna matrix. Consistent with the hypothesis that Polylepis specialists are adapted to naturally patchy landscapes, we found no evidence that Polylepis specialists were sensitive to patch size, though two of nine species were positively related to forest cover within 200 m. Our work shows that small patches of Polylepis have high ecological value and that conservation of species of concern may depend more on retaining at least 10% forest cover within landscapes than on the presence of large patches of Polylepis.

Agrostis meyenii Trin. (Poaceae, Agrostidinae): first records from Peru, including taxonomic notes and an identification key

The grass Agrostis meyenii Trin. (Poaceae, Agrostidinae) is newly recorded from Peru and is found in high-Andean puna grasslands of the departments of Ancash, Ayacucho, and Huánuco, marking the northernmost known limit of this species. A revised species description, images, taxonomic notes, and a key are also presented to differentiate A. meyenii from similar species in Peru with congested, spike-like panicles and absent or reduced (measuring less than ½ the length of the lemma) paleas (i.e., A. breviculmis Hitchc., A. foliata Hook.f., and A. tolucensis Kunth).

Agrostis meyenii Trin. (Poaceae, Agrostidinae): first records from Peru, including taxonomic notes and an identification key

The grass Agrostis meyenii Trin. (Poaceae, Agrostidinae) is newly recorded from Peru and is found in high-Andean puna grasslands of the departments of Ancash, Ayacucho, and Huánuco, marking the northernmost known limit of this species. A revised species description, images, taxonomic notes, and a key are also presented to differentiate A. meyenii from similar species in Peru with congested, spike-like panicles and absent or reduced (measuring less than ½ the length of the lemma) paleas (i.e., A. breviculmis Hitchc., A. foliata Hook.f., and A. tolucensis Kunth).

Senecio festucoides (Senecioneae, Compositae), a new species from northern Chile.

Senecio festucoides is described from northern Chile. The new species is morphologically similar to the discoid caespitose Andean species and belongs to the subgroup displaying yellow corollas and yellowish anthers and style branches. It is characterized by a weak, not self-supporting stem, narrowly linear leaves, long pedunculate capitula with (17–)21 involucral bracts, and minutely papillose achenes. Among other characters, the color of the corollas, anthers, and style branches and the number of involucral bracts differentiate it from S. scorzonerifolius, which is the morphologically closest species. The new species thrives in the desertic Puna ecoregion and grows amongst tufts of Festuca chrysophylla (Poaceae). Detailed pictures of living plants are provided, as well as a distribution map and a dichotomous key to the discoid caespitose Senecio species from northern Chile.

Diet selection and habitat use by the mountain vizcacha (Lagidium viscacia) in the Southern Andean Precordillera (Argentina)

Abstract Lagidium viscacia is considered as a fragile species with patchy distribution, a strict habitat specialist and an obligatory diet specialist. The Southern Andean Precordillera constitutes an interesting environment to analyze the species’ presence across the altitudinal gradient. Diet selection and habitat use were studied in the summit plateau, characterized by rigorous conditions and vegetation representative of the Southern Puna. Pellet groups were counted in transects perpendicular to rock formations, and diet and vegetation were seasonally analyzed using microhistological analysis and point-quadrat transects. Vizcachas were strictly associated with rock formations at middle and high altitudes, with higher occurrence on the mountain summit where grasslands surrounded the rock formations. Vizcachas avoided shrubs associated with rock formations and preferred grasses on sandy soils. Phenological changes slightly affected the selective diet that involves a considerable search effort and risky feeding activity. Puna grasslands constituted attractive feeding places where L. viscacia’s activity decreased with distance from rock shelters as expected for a central-place forager. Habitat partitioning allows coexistence with Ctenomys mendocinus, despite the high dietary overlap between these central-place species. The high mobility and broad diet of Lama guanicoe reduce the competition risk. Lepus europaeus preferred shrubs and forbs, determining a discrete dietary overlap with vizcachas.