Sierra Nevada Del Cocuy Research Articles

Changes of streamflow regulation in an Andean watershed with shrinking glaciers: implications for water security

ABSTRACT Glaciated Andean mountains have experienced several decades of shrinkage in their transition to non-glaciated regimes. This study analyses the period of hydrologic transition from 1956 to 2020 in a watershed of the Sierra Nevada del Cocuy (SNC), which is the most extensive remaining tropical glacier in Colombia. Using ground hydrometeorological data, remote sensing products, a metric of extreme flow regulation, and decadal flow duration curves, the study shows how the combined effect of continuous glacier shrinkage, highly variable precipitation regimes and increasing human extractions have altered the hydrological capacity of the watershed to regulate high, low, and mean flows. The alteration is noticeable since the 2000s, when communities have effectively benefited from the surplus of baseflow provided by the shrinking glacier to the limit, creating an unsustainable dependency with potential restrictions of use in the short run and major implications for water security of humans and the environment in the forthcoming decades.

Assessment of glacier retreat in the Sierra Nevada del Cocuy, Colombia based on multisensor image classification

Los glaciares andinos representan una de las fuentes principales del recurso hídrico en Suramérica y durante las últimas décadas se han reducido significativamente como producto del cambio climático y la variabilidad climática. En los Andes colombianos, el pico nevado más extenso corresponde a la Sierra Nevada del Cocuy (SRC), un cordón montañoso localizado al noreste de la Cordillera Oriental con presencia de nieves perpetuas en alturas que oscilan aproximadamente entre los 4800 y los 5345 metros sobre el nivel del mar (msnm). A partir de imágenes satelitales de Landsat-4 (1987), Landsat-5 (1991, 1997, 2009), Landsat-7 (2000, 2003), Landsat-8 (2014, 2016, 2017), y Sentinel-2 (2019, 2021) se realizó una clasificación orientada a píxel usando el software PCI Geomatics, en la cual se definieron 4 tipos de cobertura: área glaciar, suelo-roca, vegetación y agua. Para la validación de exactitud (accuracy) fueron utilizadas como datos de referencia, imágenes satelitales de alta resolución espacial (Google Earth ~1,0 m y Planet’s high-resolution, analysis-ready mosaics of the world’s tropics ~4,7 m) y puntos de control de campo. Los valores de exactitud global (todas las coberturas) oscilaron entre 86-99%, con una exactitud para la cobertura de área glaciar entre 97-100%. La disminución de dicha área es de 1099,59 ha en un lapso de 34 años (1987-2021). Este análisis reveló que el área glaciar disminuyó aproximadamente en un 37,92% con respecto a la primera escena (1987). Según dicha tendencia, el glaciar de la SRC se extinguiría para el año 2048. La tasa de retroceso glaciar está influenciada principalmente por factores relacionados con el calentamiento global como lo son el aumento de la temperatura media anual y la disminución en las tasas de precipitación, y factores de variabilidad climática como el fenómeno de El Niño.

Indigenous Territoriality: External Discourses and Native Perspectives on the Space Inhabited by Tegria’s U’wa Community

Tegria’s community is part of the U’wa indigenous people, who have inhabited the eastern slope of the Sierra Nevada del Cocuy since the pre-Hispanic period, in the jurisdiction of the current municipality of Cubara in Boyaca (Colombia). However, this region known as Sarare has been described from anthropological, ethnohistorical, linguistical, and to a lesser extent, geographical approaches, which have generated representations of territory that ignore the historical process of indigenous people. To account for the present territoriality, it was proposed to contrast these external discourses with the community’s visions on its history of occupation and the transformations of the inhabited space, compiled through participatory methodologies that sought the collaborative construction of knowledge based on joint recognition of the place, the participant observation and the constant dialogue between indigenous and researchers. In this way, it was established that the external discourses show a territory that does not correspond to the processes of appropriation, adaptation, and reconfiguration of the space that the U’wa indigenous community has lived through and are evident in everyday settings such as the cultivation plot and the school. Therefore, it is only possible to recognize indigenous territoriality by exploring other alternatives, expressions, and perspectives that involve directly the communities and are not external to the context of the inquiry itself.

Environmental controls over Holocene carbon accumulation in Distichia muscoides-dominated peatlands in the eastern Andes of Colombia

The long-term carbon (C) and vegetation dynamics of tropical, high-Andean cushion peatlands are poorly understood. Here, we present radiocarbon-dated paleoecological records and modern microclimate data from high-elevation peatlands currently dominated by the cushion plant Distichia muscoides in the páramo (alpine tundra) of the eastern Colombian Andes. Focusing on a well-dated 4300-year-old peat core collected at 4194 m elevation from the Sierra Nevada del Cocuy, we investigated the response of peatland vegetation to hydroclimate changes and environmental controls on C accumulation. In addition, we carried out a regional synthesis of existing C accumulation data from northern Andean peatlands to place our new results in broad geographic and temporal context over the last 17,000 years. Our results show that the current Distichia-dominated peatlands are a recent landscape feature on El Cocuy occurring only during the last ∼250 years. The Distichia peatlands have extremely high sediment accumulation rates of up to 1 cm yr−1 and C accumulation rates between 183.7 and 849.5 g C m−2 yr−1, decreasing with the elevation of a site. These rates far exceed an expected modern C accumulation rate of 110 g C m−2 yr−1, calculated by extrapolating an exponential function from a late Holocene average C accumulation rate of 48.6 g C m−2 yr−1 for the northern Andes. This suggests that recent Distichia establishment represents an acceleration of C accumulation at a rate higher than expected from decomposition-related autogenic effects. Before the modern climate warming period, our record indicates that Distichia cushions have only grown intermittently, often after the peatland was flooded with mineral sediments. Mineral sediment deposits at 3290, 2590, 1620, 930, and 860 cal. yr BP correspond with wet intervals from lake-derived records of hydroclimate change in the northern Andes and indicate increases in precipitation and subsequent in-wash of mineral sediments. However, within the last 150 years, mineral sediment deposition has increased in frequency, likely due to warming-induced melting of permanent snow and ice mobilizing exposed fluvio-glacial sediments. Increased mineral nutrients, rising temperatures, and strong diurnal temperature contrast in the tropical mountains may explain the rapid C accumulation rates. Taken together, we show that Andean peatlands have experienced the largest shift in vegetation and C accumulation rates in the last 250 years than at any other time during the last 4000 years.

Altitudinal zonation of mosses in west of the Sierra Nevada of Cocuy, Boyacá, Colombia

ABSTRACT This study was carried out with bryophyte populations in order to study the presence of populations and how they change over altitudinal gradients. Mosses were chosen as a model to do this study because they have a high sensitivity to climatic conditions and wide distribution. The western region of the Sierra Nevada del Cocuy, Boyacá, Colombia has a wide range of climate and ecosystems due to its complex topography. Plots were sampled every 200 m from the peak of Mount Mahoma at 4,200 m a.s.l. south to the Chicamocha River canyon at 1,200 m a.s.l. Diversity and cover are analyzed in each plot from soil, rock and bark substrates. We found 80 species distributed in 29 families, with Pottiaceae and Brachytheciaceae the most diverse families. Ours results show a tendency of the diversity and the coverage to increase with altitude, and we observed five altitudinal belts with three populations defined by mosses species. The Páramo and Superpáramo belts are the richest ones.

Mass occurrence of the liverwort Herbertus sendtneri in a glacial lake in the Andes of Colombia

Muchas especies de briófitas tropicales crecen en habitats periódicamente inundados como lechos del río, pantanos y cascadas, pero se presentan pocos briófitas sumergidas permanentamente y están más que todo en lagunas de alta montaña. Su identificación podría ser dificil por la modificación de rasgos inducidos por el medio acuático. Aquí se trata de una población sumergida del género Herbertus de las hepáticas de una laguna glaciar a 4120 m en la Sierra Nevada del Cocuy, Colombia. Las plantas acuáticas caracterizadas por el porte enano y los apices obtusos de las hojas. Se ha identificado como H. oblongifolius, un taxon raro descrito de Brazil y recientemente, basado en la morfología, ubicada como sinónima de la especie variable, H. sendtneri, de distribución amplia. Análisis molecular ha confirmado que las plantas acuáticas pertenecen a H. sendtneri. La semejanza de las plantas acuáticas con las ramitas de H. sendtneri parece de sugerir un fenótipo juveníl. Las plantas acuáticas probablemente tienen su origen en una población en las rocas y lajas cercanas y han llegado a la laguna a través de ramitas vegetativas caedizas y así traidas a la laguna por el viento y el agua, o plantas enteras entraron a la laguna con lluvias fuertes inundando las lajas. © 2018. Acad. Colomb. Cienc. Ex. Fis. Nat.

Variación en los restos de macrofósiles y dinámica reciente en turberas de Cojines de Distichia Muscoides de la Sierra Nevada del Cocuy, Colombia

Las turberas son ecosistemas de humedal acumuladores de materia orgánica con inundación permanente lo que los hace una reserva y sumidero de carbono. Las turberas ubicadas en los páramos ayudan a mantener el balance hídrico de los ecosistemas alrededor y regulan la distribución del agua usada por comunidades humanas. Actualmente, las turberas son afectadas por el cambio climático, el cual desequilibra el balance entre la producción de material vegetal y la descomposición. Las turberas dominadas por Distichia muscoides son particularmente importantes por su dependencia con la hidrología glaciar. El presente artículo expone una reconstrucción climática de los últimos 200 años, mediante el reconocimiento de la sucesión vegetal registrada en dos núcleos de turberas, ubicados en la Sierra Nevada del Cocuy. La vegetación reconstruida fue comparada con registros históricos de temperatura y precipitación. Nuestros resultados muestran diferencias en las trayectorias de la vegetación, con un aumento en la producción vegetal y dominancia de D. muscoides en las últimas dos décadas, relacionado con incrementos en temperatura. El balance hídrico positivo generado por el aumento global en la temperatura trae como resultado la abundancia de plantas vasculares para la turbera. El efecto del Niño de 1998 se ve reflejado en un cambio importante en las trayectorias de la vegetación de los dos sitios hacia turberas dominadas por musgos diferentes a Sphagnum que limitan la capacidad de la turbera de almacenar materia orgánica. Los efectos del cambio climático se ven multiplicados por fenómenos como la anomalía del Niño que pueden alterar la evolución de un ecosistema rápidamente, incluso de aquellos ecosistemas con alta resiliencia como las turberas.

A distinctive new subspecies of Scytalopusgriseicollis (Aves, Passeriformes, Rhinocryptidae) from the northern Eastern Cordillera of Colombia and Venezuela.

We describe a new subspecies of Pale-bellied Tapaculo Scytalopus griseicollis from the northern Eastern Cordillera of Colombia and Venezuela. This form differs diagnosably in plumage from described subspecies Scytalopus griseicollis griseicollis and Scytalopus griseicollis gilesi and from the latter in tail length. It is also differentiated non-diagnosably in voice from both these populations. Ecological niche modelling analysis suggests that the new subspecies is restricted to the Andean montane forest and páramo north of both the arid Chicamocha valley and the Sierra Nevada del Cocuy.

Phytogeography of the vascular páramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other páramo floras

Cuello, N.L., Cleef, A.M. & Aymard, G. 2010. Phytogeography of the vascular paramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other paramo floras. Anales Jard. Bot. Madrid 67(2): 177-193. Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes. Phytogeographical patterns and affinities of the low altitude and wet vascular paramo flora of Ramal de Guaramacal, have been studied with emphasis in to the analysis of the floristic connections of the Guaramacal paramo flora with the neighboring dry paramos of the Sierra Nevada de Merida and other paramo floras of the northern Andes and Central America. A total of 252 vascular plant taxa belonging to 150 genera and 69 families were recorded from the study area. The most species rich families are Asteraceae, Poaceae, Ericaceae and Orchidaceae, followed by the ferns families Grammitidaceae and Lycopodiacae. The most diverse genera are the ferns Elaphoglossum, Huperzia and Hymenophyllum. The analysis of generic phytogeographical composition of paramo flora showed that 52.8% of the genera are Tropical. The Temperate component is represented by 33.3% of the genera and the Cosmopolitan component is represented by 13.9% of the genera. The Neo tropical montane element (38.9%) is high in Guaramacal paramo, the Paramo endemic element (1.9%) and the Andean alpine element (0.9%) and represented by only one genus (Lachemilla) are low compared to other paramo areas. The vascular flora of Paramo de Guaramacal is largely composed of (1) a group of Neotropical widespread distributed species (32%), (2) a group of Andean distributed species (49%), part of them confined to the Northern Andes and part widespread in the Andes from Colombia to Bolivia, and (3) a group of Venezuelan endemics (19%). From an eight paramo flora comparative dataset, the closest relationships among paramos is observed between the generic paramo floras of the Colombian Cordillera Oriental of Sumapaz and Sierra Nevada del Cocuy, which are both close

Description of a new high Andean butterfly species (Lepidoptera: Lycaenidae: Theclinae) from the “Sierra Nevada del Cocuy”, Colombia

A new species of Penaincisalia, P. elisabeth sp. n. is described and diagnosed from the “Sierra Nevada del Cocuy” in north-eastern Colombia. Adult specimens and genitalia of both sexes are illustrated and compared with P. saraha, hypothetically the most closely related species.

Macrobiotus derkai, a new species of Tardigrada (Eutardigrada, Macrobiotidae, huziori group) from the Colombian Andes (South America)

A new species, Macrobiotus derkai sp. nov., is described from a moss sample collected in the alpine zone of Sierra Nevada del Cocuy Mts (NE Colombia). It differs from the most similar species, Macrobiotus huziori Michalczyk & Kaczmarek, 2006 mainly in the location of the second macroplacoid and in the dimensions of accessory points on the claws. Eggs of the new species have the same type of areolation as eggs of M. huziori but they differ from the latter in the size and number of processes. The differences between the new species and others having similar number and shape of placoids are discussed. An identification key for these species is also provided. A round depression on the dorsal head cuticle is reported in Tardigrada for the first time. The results of a morphometric analysis of the new species are also given.

Prácticas funerarias desde la arqueología: el caso de las momias de la Sierra Nevada del Cocuy

This article is about of archaeological theory around funerary practices. This is not only an exclusive debate about theory; but also the article shows the interpretations about funerary practices and, then, applies these theories to understand the lache mummies found in la Sierra Nevada del Cocuy, Colombia.

Fast shrinkage of tropical glaciers in Colombia

AbstractAs a consequence of ongoing atmospheric temperature rise, tropical glaciers belong to the unique and threatened ecosystems on Earth, as defined by the Intergovernmental Panel on Climate Change (Houghton and others, 2001). Worldwide glacier monitoring, especially as part of the Global Climate Observing System (GCOS), includes the systematic collection of data on such perennial surface ice masses. Several peaks in the sierras of Colombia have lost their glacier cover during recent decades. Today, high-altitude glaciers still exist in Sierra Nevada de Santa Marta, in Sierra Nevada del Cocuy and on the volcanoes of Nevados del Ruiz, de Santa Isabel, del Tolima and del Huila. Comparison of reconstructions of maximum glacier area extent during the Little Ice Age with more recent information from aerial photographs and satellite images clearly documents a fast-shrinking tendency and potential disappearance of the remaining glaciers within the next few decades. In the past 50 years, Colombian glaciers have lost 5 0% or more of their area. Glacier shrinkage has continued to be strong in the last 15 years, with a loss of 10−50% of the glacier area. The relationship between fast glacier retreat and local, regional and global climate change is now being investigated. Preliminary analyses indicate that the temperature rise of roughly 1°C in the last 30 years recorded at high-altitude meteorological stations exerts a primary control on glacier retreat. The investigations on the Colombian glaciers thus corroborate earlier findings concerning the high sensitivity of glaciers in the wet inner tropics to temperature rise. To improve understanding of fast glacier retreat in Colombia, a modern monitoring network has been established according to the multilevel strategy of the Global Terrestrial Network for Glaciers (GTN-G) within GCOS. The observations are also contributions to continued assessments of hazards from the glacier-covered volcanoes and to integrated global change research in mountain biosphere reserves.

The El Abra stadlal in the Eastern Cordillera of Colombia (South America)

The El Abra stadial is a climatic cooling event defined in the Eastern Cordillera of Colombia, which corresponds both in timing and intensity to the Younger Dryas climatic oscillation of the northern North Atlantic region. The stadial was preceded by the relatively warm Guantiva interstadial and followed by the warm Holocene. Colder climatic conditions during the El Abra stadial caused a 400 m lowering of the upper Andean forest limit below its altitudinal location during the preceding Guantiva interstadial. Translated in temperature change, this represents a drop in mean annual temperature of approximately 2 to 3°C. The lowering of the upper forest limit and inferred temperature change for the El Abra stadial, compared to Late Holocene conditions, are in the order of 600 m and 4°C, respectively. The transition of the Guantiva interstadial to the El Abra stadial has been radiocarbon dated at 11,210 ± 90 BP and 10,820 ± 60 BP. Climatic warming may have started shortly after 10,380 ± 90 BP, and near present-day temperatures were reached at least as early as 8920 ± 100 BP. Maximum cooling was probably attained between 10,800 BP and 10,300 BP. Further (AMS) radiocarbon dating is planned to establish more exactly the timing of the El Abra stadial. A glacial advance of El Abra age, the Bocatoma stade, has been recognized in the highest part of the Colombian Eastern Cordillera, the Sierra Nevada del Cocuy. During this advance, glaciers extended some 700 m lower than at present. A climatic cooling event of El Abra age, associated with shifts of the upper Andean forest limit and glacial advances, has also been recognized in other parts of Andean Colombia, including the Central Cordillera and the Sierra Nevada de Santa Marta.

Glacial sequence and environmental history in the Sierra Nevada del cocuy (Colombia)

The glacial sequence in the area of the Sierra Nevada del Cocuy (Cordillera Oriental, Colombia) was studied in the field and by means of aerial photographs in relation to the environmental history, which was studied by means of pollen analysis and radiocarbon dating. At least five (possibly six) glacial drift bodies could be recognised, and on the basis of the (groups of) bordering moraines about six main glacial stades were defined and named. Drifts 2, 3, 4 and 5 are presumably all of Fuquenian (Last Glacial) age, whereas Drift 6 is of Holocene (Neoglacial) age. In the pollen diagrams the Saravita, Susacá and Guantiva interstadials are clearly reflected as periods of a somewhat higher forest limit, a more abundant growth of Polylepis and an interesting pioneer vegetation (often with Dodonaea). The greatest extension of the glaciers took place before ca. 25,000 B.P., probably in the period between 45,000 B.P. and 25,000 B.P. The climate was relatively wet at the time and the forest limit something like 800–1000 m below the present one, and during the early period of major extension of the ice, glaciers and forest may have locally been in contact (at elevations between 2200 and 2700 m), and the páramo belt was relatively narrow and wet, with Polylepis abundant in the lower parts. Between 21,000 and 14,000 B.P., the ice extension was much less, the forest limit lower, and the climate drier, which resulted in a relatively broad and dry páramo belt. The late Glacial had a relatively wet climate again, but the annual temperature increased; there are two clear “glacial stades”. There are very clear signs of a late medieval neoglaciation; glaciers started to retire from the outermost Neoglacial bordering moraines probably after 1850 A.D., and are still decreasing.

Palynological record of the upheaval of the Northern Andes: A study of the pliocene and lower quaternary of the Colombian Eastern Cordillera and the early evolution of its high-Andean biota

The present paper deals with the stratigraphy and palynology of the Pliocene and Lower Quaternary formations of the central part of the Colombian Eastern Cordillera. Three Plio-Pleistocene formations are distinguished: the Tilata Formation is of Pliocene and Earliest Quaternary, the Subachoque Formation of Early Quaternary, and the Sabana Formation of Middle and Late Quaternary age. Four pollen zones have been distinguished the Tilata Formation, the first three being of Pliocene, the fourth of Earliest Pleistocene age. Zone I shows a purely tropical lowland flora and zone IV a high-mountain flora, whereas zones II and III show floras of intermediate altitude. A gradual elevation by more than 2,000 m has in this way been recorded palynologically for the area of the high plain of Bogotá. Actually, the top level of the Tilatá Formation lies at ca. 2,850 m alt. in the area east of Chocontá. The top level of the Subachoque Formation lies at ca. 2,700 m alt. in the Subachoque and Guasca valleys. The sediments correspond with pollen zone V of Early Quaternary age, exhibiting a high-mountain flora and indicative of glacial conditions. Sediments corresponding with the same pollen zone have been found between 140 m and 195 m below the surface (2,580 m alt.) in a borehole in Bogotá, showing that the wide central part of the high plain may have relatively subsided more than 200 m since the end of the Early Quaternary. The Sabana Formation, whose top has an actual maximum elevation of 2,600 m, corresponds with major pollen zones VI and VII and exhibits a sequence of glacials and interglacials belonging to the Middle and Late Quaternary. The pollen types important for time correlation between the tropical and mountain environments, belong the anemophilous taxa: pollen of Hedyosmum appears in zone II, of Myrica in zone III, of Alnus in zone V–VI and of Quercus in zone VII. During the process of upheaval tropical and subtropical species gradually disappeared from the area owing to the changing ecological conditions, to be gradually replaced by species better adapted to the new circumstances. It is striking that the oldest, cold to temperate flora (zone IV) is still poor in species. Apart from the dominant grasses, Aragoa, Hypericum, Valeriana, Plantago and Polylepis are amongst the oldest high-mountain (páramo) plants. This flora was later gradually enriched both by immigrants from the north (Holarctic) and the south (Antarctic) and, mostly, by endemic elements originated by the evolutionary adaptation of the local neotropical flora. In this way the Colombian Eastern Cordillera provides us, in its Plio-Pleistocene sediments, with a, so far unique, example of the gradual in situ evolution of tropical high-mountain biota. Because of the scarcity of species adapted to the High-Andean environment, it appears that the forest limit in the Early Quaternary was lower and the Andean forest belt narrower than is the case at present. The first glacial periods of the Early Pleistocene were already so severe, that a temporary, additional lowering of the forest limit by, probably, 500–800 m resulted. At the same time fluvio-glacial gravels were deposited in many places, and huge masses of the old tropical weathering products still covering the mountains at that time were removed by solifluction fromthe slopes downwards into the marginal areas of the basin of the high plain. During the Early Quaternary the large Pleistocene lake of the Sabana de Bogotá was formed, and as the result of progressive and probably continuous subsidence, deposits of hundreds of metres of lake sediments accumulated in the basin during the Pleistocene. From the present data it may be concluded that the major ultimate upheaval of the Cordillera took place during the Middle-Late Pliocene, and that it probably ceased before the beginning of the Pleistocene. The average rate of upheaval may be estimated at between 1 and5 mm per year, but it may have been twice as much in the area of the Sierra Nevada del Cocuy.