Paramo Ecosystems Research Articles

Comunidades vegetales de las transiciones terrestre-acuáticas del páramo de Chingaza, Colombia.

Plant communities in the terrestrial-aquatic transition zone in the paramo of Chingaza, Colombia. High Andean paramo ecosystems are an important water resource for many towns, and major cities in this region. The aquatic and wetland vegetation of different paramo lakes, pond, swamps and bogs was studied according to the classical phytosociological approach, which is based on homogenous stands, but excludes any border phenomena or transitional zone. The present research aimed at determining the aquatic and wetland vegetation along different moisture gradients. A total of 89 species in 30 transects were reported, of which Crassula venezuelensis, Carex honplandii, Callitriche nubigena, Eleocharis macrostachya, Ranunculus flagelliformis, R. nubigenus, Eleocharis stenocarpa, Galium ascendens y Alopecurus aequalis were present in more than one third of the transects. Numerical classification and indicator species analysis resulted in the definition of the next 18 communities: 1) Calamagrostis effusa, 2) Sphagnum cuspidatum, 3) Cyperus rufus, 4) Eleocharis stenocarpa, 5) Carex acutata, 6) Poa annua,7) Valeriana sp., 8) Ranunculus flagelliformis, 9) Carex bonplandii, 10) Festuca andicola. 11) Muhlenbergia fustigiata, 12) Elatine paramoana, 13) Isoëtes palmeri, 14) Crassula venezuelensis, 15) Lilaeopsis macloviana, 16) Callitriche nubigena, 17) Potamogeton paramoanus and 18) Potamogeton illinoensis. The ordination of communities reveals the presence of three different aquatic-terrestrial gradients which are related to the life form structure of species that characterized the various communities. We concluded that patchiness and heterogeneity of the vegetation is mainly the result of alterations caused by human activities (burning, cattle raise and material extraction for road and dam construction).

Exploring the biocontrol potential of fungal endophytes from an Andean Colombian Paramo ecosystem

We studied the diversity and biocontrol potential of 100 fungal endophytes isolated from Espeletia spp., endemic plant species from the Paramo in the Andean mountain range. Our sample was genotypically highly diverse at all ITS similarity levels. The antagonistic properties of these isolates were tested against common crop pathogens in Colombia, including Pectobacterium carotovorum, Ralstonia solanacearum, Pseudomonas syringae, Xanthomonascampestris, Rhizoctonia solani, Botrytis cinerea, Fusarium oxysporum, and Phytophthorainfestans. All endophytic isolates were able to significantly inhibit the growth of at least one of the plant pathogens tested (P < 0.05). Three main types of endophyte/pathogen interactions were observed. However, only those endophytes that produced an evident inhibition halo were further studied using their crude extracts to confirm that the inhibitory effect was due to the production of endophytic bioactive metabolites. From these experiments, nine promising isolates were selected for co-inoculation tests with R. solani in tomato plants. The isolates identified as Aureobasidium pullulans and Paraconiothyrium sporulosum not only protected the plants against this pathogen but also allowed them to exhibit similar growth and development as the uninoculated control. This work explores new alternatives for disease management without the application of chemical pesticides.

Trends, stability and stress in the Colombian Central Andes

Mountain ecosystems have been projected to experience faster rates of warming than surrounding lowlands. These changes in climatic conditions could have significant impacts on high-altitude Andean environments, affecting the quality and magnitude of their economic and environmental services. Even though long-term data in these regions are limited, it is important to identify any discernible long-term trends in local climatic conditions. Time series of several variables were analyzed to detect statistically significant long-term linear trends that occurred over recent years in a paramo ecosystem of the Colombian Central Andes. Records included cloud characteristics, sunshine, rainfall, minimum and maximum temperatures, diurnal temperature range, and relative humidity. Conditions of atmospheric stability were also explored. Total sunshine exhibited decreasing trends ranging from −3.7 to −8.5% per decade at altitudes around the pluviometric optimum. The strongest changes in sunshine occurred during the December-January-February season. Mean relative humidity observed at altitudes around and below this threshold showed increasing trends of +0.6 to +0.7% per decade. Annual rainfall and mean relative humidity above the optimum showed decreasing trends ranging from −7 to −11% per decade and from −1.5 to −3.6% per decade, respectively. Minimum temperatures on the coldest days and maximum temperatures on the warmest days exhibited increasing trends at all altitudes ranging from +0.1 to +0.6, and from +0.2 to +1.1°C per decade, respectively. Increases in minimum and maximum temperatures at higher altitudes were significantly greater than those observed in average at lower altitudes. The strongest changes in minimum temperatures, particularly, occurred during the December–January–February and June–July–August dry seasons. All these changes suggest that atmospheric conditions in the area are shifting from statically unstable conditions to conditionally unstable or statically stable conditions. Observed historical trends indicate that climate impacts and other human activities have stressed these unique and fragile environments.

Models as multiple working hypotheses: hydrological simulation of tropical alpine wetlands

Tropical alpine grasslands, locally known as paramos, are the water towers of the northern Andes. They are an essential water source for drinking water, irrigation schemes and hydropower plants. But despite their high socio-economic relevance, their hydrological processes are very poorly understood. Since environmental change, ranging from small scale land-use changes to global climate change, is expected to have a strong impact on the hydrological behaviour, a better understanding and hydrological prediction are urgently needed. In this paper, we apply a set of nine hydrological models of different complexity to a small, well monitored upland catchment in the Ecuadorian Andes. The models represent different hypotheses on the hydrological functioning of the paramo ecosystem at catchment scale. Interpretation of the results of the model prediction and uncertainty analysis of the model parameters reveals important insights in the evapotranspiration, surface runoff generation and base flow in the paramo. However, problems with boundary conditions, particularly spatial variability of precipitation, pose serious constraints on the differentiation between model representations.

Influencia de los patrones de uso actual de la tierra sobre la dinámica de la vegetación en el páramo de Rabanal, vereda San Antonio, municipio de Guachetá

&lt;p&gt;&lt;strong&gt;&lt;/strong&gt;Los patrones del uso actual de la tierra en el páramo de Rabanal parecen indicar un lento y progresivo deterioro de la vegetación característica de este ecosistema, debido probablemente a su régimen actual de disturbios impuesto al parecer en gran medida por causas humanas, evidenciándose principalmente la ampliación de la frontera agrícola (cultivos de papa mecanizados) y pastoreo. La situación característica en la cual se llevan a cabo los patrones de ocupación y tenencia de la tierra en estos lugares, así como el sistema de producción que se establece son el punto de partida para determinar su efecto sobre este sector del ecosistema paramuno de Rabanal y definir si realmente esta circunstancia es determinante para buscar su conservación y manejo.&lt;/p&gt;&lt;p&gt;El trabajo se realizó en tres etapas que consistieron en la caracterización de la zona, la cual se realiza bajo la recolección de encuestas, revisión de información primaria y secundaria, seguida de un trabajo de campo, para finalizar en la tabulación de la información.&lt;/p&gt;&lt;p&gt;&lt;br /&gt;El presente estudio arroja unos resultados que pretenden aportar al conocimiento de uso actual de la tierra en un sector de la vereda San Antonio - municipio de Guachetá, inmediato al páramo de Rabanal y con este dar las bases necesarias para comprender la forma como opera la intervención antropogénica en el área y sus implicaciones en la dinámica de la vegetación, y el conocimiento de sus sistemas de producción.&lt;/p&gt;

Late Holocene environmental change and human impact inferred from three soil monoliths and the Laguna Zurita multi-proxi record in the southeastern Ecuadorian Andes

Late Holocene vegetation, climate and fire dynamics of mountain forest and paramo ecosystems, as well as human impact, are presented from the upper Rio San Francisco valley, southeastern Ecuadorian Andes. Palaeoenvironmental changes, inferred from three soil monoliths, spanning an altitudinal gradient between 1,990 and 3,200 m and the high resolution multi-proxy sediment record from Laguna Zurita (2,590 m), were investigated by pollen, spore and charcoal analyses, in combination with XRF- and magnetic susceptibility-scanning. Three of the four pollen records show a marked change in the floristic composition between ca. 900 and 350 cal b.p. (interpolated age). Past fires have strongly influenced the floristic composition of the mountain rainforest ecosystem. Frequent fires, together with the relatively high occurrence of grasses and some Zea mays plantations document past human activities in the upper Rio San Francisco valley. A large number of areas of probably ancient Z. mays cultivation in the upper Rio San Francisco valley has been identified, using GIS-based calculation. High occurrences of Cyperaceae and Isoetes indicate the development of marshy lake shores in response to a lower lake level at Laguna Zurita before ca. 700 cal b.p. The decrease of Isoetes and Cyperaceae after ca. 1200 cal b.p. reflects a lake level rise, due to increasing moisture and/or human activities.

Late Pleistocene and Holocene environmental change inferred from the Cocha Caranga sediment and soil records in the southeastern Ecuadorian Andes

Late Pleistocene and Holocene vegetation, climate and fire dynamics of mountain forest and paramo ecosystems, as well as human impact, are presented from the Cocha Caranga area, at 2710 m elevation in the Podocarpus National Park, southeastern Ecuadorian Andes. Palaeoenvironmental changes, inferred from two sediment cores and a soil core were investigated by pollen, spore, algae and charcoal analyses. During the transition from late Pleistocene to early Holocene between ca. 14,500 to 9700 cal yr BP upper mountain forest vegetation expanded, suggesting increasing temperature and moisture. This expansion abruptly stopped with increasing fires at ca. 9700 cal yr BP and open grassy vegetation became established. The period from ca. 9700 to 1300 cal yr BP of strong fire intensity indicate that vegetation components, mainly Weinmannia and Myrica, react sensitively to past, probably human caused fires. During the last few centuries modern vegetation established, characterised by open grassy areas with forest patches and small mires. The green algae Botryococcus braunii, Isoetes and Cyperaceae were used to identify lake level fluctuation to reconstruct Holocene wet/dry phases. Drier climatic conditions occurred from ca. 9700 to 6900 cal yr BP and from ca. 4200 to 1300 cal yr BP. From ca. 6900 to 4200 cal yr BP and from ca. 1300 cal yr BP to modern times, wetter climatic conditions occurred.

Late Quaternary vegetation, climate and fire dynamics inferred from the El Tiro record in the southeastern Ecuadorian Andes

AbstractIn order to study the stability and dynamics of mountain rainforest and paramo ecosystems, including the biodiversity of these ecosystems, the Holocene and late Pleistocene climate and fire variability, and human impact in the southeastern Ecuadorian Andes, we present a high‐resolution pollen record from El Tiro Pass (2810 m elevation), Podocarpus National Park. Palaeoenvironmental changes, investigated by pollen, spores and charcoal analysis, inferred from a 127 cm long core spanning the last ca. 21 000 cal. yr BP, indicate that grass‐paramo was the main vegetation type at the El Tiro Pass during the late Pleistocene period. The grass‐paramo was rich in Poaceae, Plantago rigida and Plantago australis, reflecting cold and moist climatic conditions. During the early Holocene, from 11 200 to 8900 cal. yr BP, subparamo and upper mountain rainforest vegetation expanded slightly, indicating a slow warming of climatic conditions during this period. From 8900 to 3300 cal. yr BP an upper mountain rainforest developed at the study site, indicated by an increase in Hedyosmun, Podocarpaceae, Myrsine and Ilex. This suggests a warmer climate than the present day at this elevation. The modern subparamo vegetation became established since 3300 cal. yr BP at El Tiro Pass. Fires, probably anthropogenic origin, were very rare during the late Pleistocene but became frequent after 8000 cal. yr BP. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Soil Organic Carbon and Water Retention after Conversion of Grasslands to Pine Plantations in the Ecuadorian Andes

Tree plantations in the high elevations of the tropics constitute a growing land use, but their effect on ecosystem processes and services is not well known. We examined changes in soil organic carbon (C) and water retention in a chronosequence of Pinus radiata stands planted in paramo grasslands in Cotopaxi province, Ecuador. Water retention at 10, 33, and 1,500 kPa declined with stand age, with soils in the oldest pine stands retaining 39%, 55%, and 63% less water than grassland soils at the three pressures tested. Soil organic C in the 0–10-cm depth also declined with stand age, from 5.0 kg m−2 in grasslands to 3.5 kg m−2 in 20–25-year-old pine stands (P < 0.001); at greater depth in the A horizon, C contents decreased from 2.8 to 1.2 kg m−2 (P = 0.047). There were no significant differences among age classes in the AC and C horizons (P = 0.15 and P = 0.34, respectively), where little or no weathering of the primary material has occurred. Inputs of C may be affected by the significantly higher carbon–nitrogen (C:N) ratio of the litter under older pine stands (P = 0.005), whereas outputs are influenced by substrate quality as well as soil environmental factors. Soil ratios at the 0–10 cm depth were significantly higher in grasslands and young pine stands (P < 0.001), whereas carbon–phosphorous (C:P) ratios at 0–10-cm depth followed a similar but not significant trend. However, there was no significant difference in short-term decomposition rates (P = 0.60) when the soils were incubated under uniform temperature and moisture conditions. In paramo ecosystems, where high soil moisture plays an important role in retarding decomposition and driving high C storage, the loss of water retention after afforestation may be the dominant factor in C loss. These results suggest that soil C buildup and water retention respond rapidly to changes in biota and need to be assessed with regard to implications for C sequestration and watershed management.

Brain &amp; Degussa establish new biotech project

Soil is one of the most variable and complex habitats on earth where microbial communities and their metabolic capabilities are greatly affected by agricultural activities. Nevertheless, the impact of these activities has been poorly studied and more detailed analyses are required in order to understand soil ecosystems at both a structural and metabolic level. Here, we conducted a detailed metagenomics analysis to establish the effect of anthropogenic interventions on microbial communities and on the biogeochemical cycle dynamics in soil. Our results suggest that the agricultural activities lead to shifts in the structure of microbial communities characterized by an increase in ammonia-oxidizing archaea, bacteria with copiotrophic features, and ascomycete fungi. The most important biogeochemical processes were related to the carbon and nitrogen cycles. These shifts in the composition of microbial communities led to a loss in the metabolic functional diversity, which was reflected by the lower metabolic activity found. On the other hand, in the non-intervened soil, an increased metabolic activity was observed. The biogeochemical cycles behaved in an interdependent and synergistic way. We were able to elucidate how soil ecosystems dynamics is influenced by agricultural activities in a paramo ecosystem in Colombia.

Observations on the diet and habitat of the mountain tapir (Tapirus pinchaque)

AbstractResults of a 4‐year study in Sangay National Park, Ecuador, indicated that the mountain tapir Tapirus pinchaque, consumes a wide variety of woody and non‐woody plant taxa primarily as a foliose browser, and has a preference for some nitrogen‐fixing plants. The more closed‐cover Andean forest and chaparral habitats contain a greater abundance of mountain tapir‐favoured food than the more open grassland paramo, riverine meadow, and pampas vegetation types. Andean forests are considered the most critical habitat for the survival of this tapir because of their provision of cover and food. Field observations and results of faecal germination experiments show that the mountain tapir assists in the successful seed dispersal of many species of Andean plants. Significant regressions between: (1) seed germination and (2) both the natural logarithm (ln e) of the preference ratio and the dietary abundance of food species indicate a mutualism between the mid to high montane‐dwelling mountain tapir and the plants it consumes. A significant relation during the past 2 to 3 million years is proposed between: (1) the crossing of the Panamanian Isthmus and the occupation of the mid to high northern Andes by ancestors of the mountain tapir, and (2) the rise of the Andes and formation of the montane forest and paramo ecosystems above c. 2000 m elevation.

Effects of Burning and Grazing on a Colombian Paramo Ecosystem

Effects of Burning and Grazing on a Colombian Paramo Ecosystem