High-altitude Vegetation Research Articles

Plant community on a volcano mountaintop reveals unique high-altitude vegetation in southeastern Brazil

Plant community on a volcano mountaintop reveals unique high-altitude vegetation in southeastern Brazil

High altitude Pliocene to Pleistocene vegetation and climate change of the Kunlun Pass Basin, NE Tibetan Plateau

The world largest alpine permafrost region, the Tibetan Plateau, will experience amplified warming under global climate change scenarios. Studying its environmental evolution in the geological past is crucial to further our understanding of mechanism and thresholds of climate change. Here we present a 3.5-million-year-long, high-altitude vegetation and climate record from the Kunlun Pass Basin to reconstruct the transition from the sustained warm, high carbon dioxide environment of the Pliocene to the cool glacial and interglacial periods of the Pleistocene, 4.31 to 0.85 million years (Ma) ago. The Early Pliocene pollen record indicates the occurrence of patches of broadleaved and coniferous forests in a semi-desert shrubland at this high-altitude site. Pollen derived quantitative climate estimates based on modern pollen rain transfer functions suggest a moister climate before 4.0 Ma with mean annual temperatures (MATs) > 14 °C warmer than today. The retreat of broadleaved and coniferous forests from the Kunlun Pass Basin area is linked to stepwise cooling at ∼4.0 Ma and during the Plio-Pleistocene transition between 2.7 and 2.6 Ma. Pollen derived climate estimates and Δ47-palaeothermometry indicate an abrupt cooling of ∼4–8 °C resulting in the onset of permafrost condition on the Tibetan Plateau after 2.7 Ma. An expansion of Chenopodioideae dominated xerophytic shrublands after 3.8 Ma and 2.15 Ma indicates a reduction in precipitation on the NE Tibetan Plateau, which appears to be linked to a weakening of the East Asian Summer Monsoon at the Plio-Pleistocene transition. The reconstructed cooling at the Kunlun Pass Basin site reflects the regional expression of global climate change with high-elevation temperature amplification hence rejecting the notion of a major tectonic uplift of the Tibetan Plateau during the Plio-Pleistocene.

Application of Remote Sensing to the analysis of changes in high-altitude vegetation of the ‘Pantanal’ (Brazil) using multitemporal Landsat data

Devido ao clima frio e altitude, identificar as tendências dinâmicas da vegetação e os principais fatores que contribuem para mudanças de cobertura vegetal em áreas de Campos de Altitude é essencial para entender alterações climáticas em regiões montanhosas. Imagens Landsat-8 OLI e Landsat-1 MSS de 1973 a 2022 da Morraria do Urucum e Serra do Amolar foram pré-processadas na plataforma de nuvem GEE e QGIS. O método de reamostragem por pixel na escala de valores definidos para vegetação Campos de Altitude foi empregado para evidenciar mudanças da cobertura da vegetação e suas dinâmicas através do índice NDVI. Em ambas as áreas de estudo foi verificada tendência contínua de redução significativa da vegetação de campos de altitude em 50 anos. O decréscimo médio foi de 49% para Urucum (menos 2.164 hectares) e 43% para o Amolar (menos 3.959 hectares). O uso do GEE para obter dados de sensoriamento remoto combinado com a análise de imagens temporais oferece o potencial de perceber rapidamente tendências de mudança de cobertura da vegetação em grande e pequena escala

Loss of Natural Habitats: High-Altitude Vegetation, Pantanal

The objective of this study is to quantify the spatiotemporal variation of high-altitude grassland (Campos de Altitude) in two different study areas between 1985 and 2020. First, the types of vegetation present in both areas were classified using a false-color (Red, Green, Blue) composition, with the channels replaced by mid-infrared, near-infrared, red, respectively. Following the definition of vegetation classes and the creation of polygons over them, they were superimposed on the NDVI product (1985 and 2020) to obtain the maximum and minimum values of the index and to identify which value ranges each class would be in. Next, a multitemporal false-color composition was carried out with the modification of the Red channel by the NDVI 1985 product, the Green channel by the NDVI 2020 product and the Blue channel without any changes. The results show that the total area of Campos de Altitude decreased between 1985 and 2020 in both study areas, with area 1 losing 31.93% and area 2 losing 35.12%, whereas the vegetation of denser strata (arboreal) increased in its spatial distribution in both study areas, with area 2 gaining the most (230%). There was a noticeable increase in arboreal vegetation in the two study areas during the years analyzed. The tendency for the fraction of arboreal vegetation cover to increase is in line with the decrease in Campos de Altitude vegetation, and this phenomenon may be related to environmental factors such as temperature variations, amount of rainfall, solar radiation, and soil composition.

Nematode community structure along elevation gradient in high altitude vegetation cover of Gangotri National Park (Uttarakhand), India

The study was undertaken to understand the dynamics of soil nematode communities association along elevation gradient and associated variables in high-altitude regions of Western Himalaya. The diversity and distribution pattern of soil nematodes were investigated at four elevation ranges (Elv1, Elv2, Elv3, and Elv4 each of 500 m class) along altitudinal gradient (3000–5000 m). The nematode community comprised 58 genera of which 37 genera showed sensitivity towards altitudinal variation and the community structure also varied among elevation classes. It was found that elevation significantly affect the nematodes trophic group, diversity composition, and the nematode indices. Nematode generic richness and evenness index indicated a relatively low biodiversity of soil nematodes is supported at higher altitudes. Moreover, maturity indices reflected lower sustenance of k-strategic nematodes at higher elevations. Structure index depicted fewer connections in the soil food web at higher elevations. Nematode faunal profile showed low nutrient and low disturbance in the region. Carbon footprint of the whole nematode assemblage declined along the elevation. Overall substantial differences in the nematode composition, abundance, trophic structure, and contribution to belowground carbon cycling were observed with change in elevation. These findings could be utilized as useful tool in the long-term monitoring and to understand the region's soil health.

ОБЩИЕ ЗАКОНОМЕРНОСТИ РАСПРОСТРАНЕНИЯ РАСТИТЕЛЬНЫХ СООБЩЕСТВ В КЛАСТЕРЕ «ЦЕНТРАЛЬНЫЙ» ЗАПОВЕДНИКА «БАСТАК»

The article presents the patterns of plant communities distribution in the cluster «Central» of the nature reserve Bastak. Forest is the dominating type of vegetation in that specially protected natural area. There distinguished two high-altitude vegetation zones: broad-leaved-coniferous and dark-coniferous forests. The author shows the main factors determining the plant communities distribution in the protected area.

Role of Bumblebees (Hymenoptera: Apidae) in Pollination of High Land Ecosystems: A Review

Bumblebees are one among the anthophilous form and play a significant role in the pollination of major agricultural crops like medicinal, aromatic, ornamental and various other horticultural plants. They are abundant and mostly confined to flowers present in the temperate, alpine and arctic climates of the northern continents. The bumblebees are considered as most important pollinators and are mainly responsible for the conservation of high altitude vegetation germplasm where other insect pollinators are very much limited. They are more successful pollinators and can visit large number of flowers per minute than other bees and are perfect for picking up and transferring appreciable amount of compatible pollen to flowers and thus perform buzz pollination. It is quite evident that the population of bumblebee is gradually declining throughout the globe for the last 7 decades due to agricultural intensification, habitat loss, deforestation, overgrazing, pesticide poisoning and climate change. The present paper addresses this issue on the basis of literature survey.

Plant diversity patterns along environmental gradients in Nanda Devi Biosphere Reserve, West Himalaya

Mid to high-altitude vegetation in part of west Himalaya, India has been investigated and analyzed for assessing species distribution in relation to environmental variables. The buffer zone site of Nanda Devi Biosphere Reserve (NDBR) in Pindari–Sunderdhunga–Kafni (PSK) area (30 forest stands in 11 forest communities) of Kumaun and Lata–Tolma–Phagti (LTP) area (30 forest stands in 8 forest communities) of Garhwal region having 11 forest communities along different elevation gradients was identified for detailed surveys. Species composition showed a total of 451, distributed in NDBR along Pindari–Sunderdhunga–Kafni site and Lata–Tolma–Phagti transects. Among communities, Quercus semecarpifolia and Mixed Abies pindrow-Quercus spp. communities in Pindari–Sunderdhunga–Kafni site with 23 species each and Pinus wallichiana community in Lata–Tolma–Phagti site with 18 species showed highest species composition. The interrelationship between environmental variables and species distribution was analysed using Simple Linear Correlation analysis and Canonical Correspondence Analysis (CCA). Simple Linear Correlation and CCA indicated compositional differences in forest types that perhaps was caused by differences in species richness and forest composition. In both the sites, among all the environmental variables, elevation, slope and organic carbon were found to be the most controlling factor for species distribution. Different forest structural components like species richness, total basal area, canopy density was found to be varying greatly with environmental factors and human disturbance, however, more datasets of vegetation dynamics and responses are required to further strengthen this premise.

Reliability of leaf functional traits after delayed measurements

In this study, the effect of temporary storage (at 4°C) on measurement of leaf traits was tested. We collected leaf samples from 25 species, which represented different functional types in the high altitude vegetation of western Himalaya, to measure leaf area (LA), leaf rehydration, specific leaf area (SLA) and leaf dry matter content (LDMC). Repeated trait measurements were performed for up to 7 days. We found that in all the species, LA increased in initial 24 h of rehydration and thereafter remained stable. Leaf rehydration was found to be sensitive to delayed measurements and changed significantly for up to 7 days. For SLA and LDMC, the effect of storage time was significant only for a few species. On the basis of our findings, we recommend that, for samples stored in dark at 4°C, LA, SLA and LDMC can reliably be estimated after a delay of up to 7 days. Further, these key leaf traits should be estimated only after 24 h of rehydration. Also, trait measurements after prolonged rehydration of leaves should be avoided. Outcomes of this study will be beneficial when a large number of samples are collected from locations far away from laboratory and temporary storage is necessitated before trait measurements.

Effect of Temperature and Precipitation on the Vegetation Dynamics of High and Moderate Altitude Natural Forests in India

In the present study, the high-altitude vegetation dynamics of natural forest cover were analyzed to find the effect of local hydrology for about 10 years. Vegetation dynamics in four different topographical and climatic conditions in India were studied using normalized difference vegetation index (NDVI) data from vegetation sensor of SPOT satellite, and daily temperature and precipitation data from Asian Precipitation–Highly Resolved Observational Data Integration Towards Evaluation project. The main objective was to understand how and to what extent the natural vegetation reciprocates in various climatic conditions. First, the vegetation data was denoised by using empirical mode decomposition technique. The relation between the vegetation growth and hydrological parameters was studied to find the anomalies. Then, the wavelet analysis of the hydrological data was carried out to find the frequency and extent of the anomalies. Finally, nonparametric Mann–Kendall trend analysis and Sen’s slope analysis were applied to find the trend of the vegetation, temperature, and precipitation dynamics. Results indicate that the growth of the vegetation starts when the average temperature is 10 °C or higher. Beyond that the increase in temperature may have a negligible effect on growth of vegetation. The vegetation also shows positive change in monthly NDVI with the increase in precipitation depending forest type and local climate. However, with excessive rainfall, a declining trend in vegetation growth was observed. The NDVI data show positive trend in all four sites. In northern region, the temperature showed positive trend, while precipitation had negative trend. In eastern and western regions, the temperature had negative trend and precipitation had positive trend.

Functional diversity along elevational gradients in the high altitude vegetation of the western Himalaya

The analysis of species distribution and functional diversity (FD) in natural gradients of aridity and temperature at high altitudes could provide indication of future changes in plant communities as both are responsive to environment and strongly influence ecosystem functioning and stability. We established eleven altitudinal transects in high altitude region of western Himalaya, six of which represented north aspect and the rest represented south aspect. In each transect, vegetation was sampled randomly at every 200 m elevation to estimate species rarity, niche width and different FD indices [community-weighted mean traits (CWM), functional richness (FRic), functional divergence (FDiv), functional dispersion (FDis) and functional specificity (FSpe)]. These indices indicate resource utilization, competition for resources, optimal plant strategies, and presence of functionally specialist species. We found a total of 418 plant species, most of which were having narrow niche and distribution. Proportion of species with narrow niche was high at higher elevations, 36.5% species were rare with 17% of them being endemic to Himalaya. At south aspect, lower values of CWM plant height along with lower FRic, FDiv, FDis, and FSpe were recorded. Further, CWM plant height, FRic, FDiv, FDis and FSpe significantly decreased with increasing elevation. Influence of gradients of aridity (aspect) and decreasing temperature (elevation) on species distribution and FD suggest that functioning of high altitude communities is very likely to be affected in future. Our findings therefore emphasize that the plant communities present at higher elevations are more vulnerable under climate change.

Increase in light interception cost and metabolic mass component of leaves are coupled for efficient resource use in the high altitude vegetation

Global syntheses of leaf trait scaling relationships report an increase in light interception costs or ‘diminishing returns’ with increase in leaf area. However, variation in light interception costs across ecological gradients and plant strategies to cope up with these costs are not adequately understood. We analyzed leaf area (A) – leaf dry mass (M), leaf water mass (W) – M and W – A scaling relationships in plants occurring in a high altitude region of western Himalaya across environmental gradients to understand changes in light interception cost and metabolic mass component. M represents light interception cost, whereas, W is considered as a proxy of metabolic mass component for liquid phase being the ultimate source of metabolic activity. Trait values were measured from 9278 leaves belonging to 136 dominant species occurring at different sites, slope aspects, elevations and habitat types. Overall, light interception cost increased with increasing A (scaling exponent (α) < 1 in A–M relationship) and metabolic mass component increased disproportionately high with increasing M and A. We found significant differences in scaling exponents of leaf trait relationship between sites, elevations, slope aspects and habitat types, indicating that increase in light interception cost was more evident at higher elevations, southern slopes and open habitats. Further, with increase in light interception cost, metabolic mass component also increased (α > 1 in W–M and W–A relationships). The changes in scaling exponents of various leaf trait relationships across ecological gradients indicated that vegetation of different regions have differences in light interception cost and metabolic mass component. Moreover, increasing light interception cost (increase in mechanical and hydraulic tissues) with increasing A and increasing metabolic mass (leaf thickness) with increasing A and M are favored in high altitude vegetation. This could be a key strategy of high altitude plants for efficient resource capture and use in harsh environments.

8800 years of high-altitude vegetation and climate history at the Rutor Glacier forefield, Italian Alps. Evidence of middle Holocene timberline rise and glacier contraction

Sedimentary archives at or near the timberline ecotone in Alpine glaciated areas contain records to study Holocene climate change and the interplay between climate, ecosystems, and humans. We focused on records of timberline and glacier oscillations in the Rutor Glacier forefield (Western Italian Alps) in the last 8800 years. Human activity in this area was negligible for most of the Holocene. We adopted an integrative stratigraphic approach including proxies for glacier advance and timberline estimation, sedimentary events, and reconstructed temperatures. Changes in timberline ecotone correlate to climate until the Middle Ages. Pollen-stratigraphic evidence of a primary plant succession highlights a lag beween local deglaciation and the first reliable 14C age. The radiocarbon chronology points to a prolonged phase of glacier contraction between 8.8 and 3.7 ka cal BP. Even later the glacier remained within its LIA limits. Between 8.4 and 4 ka cal BP MAT-inferred TJuly fluctuated near 12.4 °C, ca. 3.1 °C higher than today. During this period, a Pinus cembra forest belt grew at 2600 m asl with an upper limit of tree groves placed 434 ± 310 m above the current open forest limit. This Holocene phase of thermal maximum ended between 3.98 and 3.51 ± 70 ka cal BP and with a substantial rearrangement of forest composition; temperature reconstruction shows a decrease of 1.8 °C. This climate deterioration concluded the Subboreal thermal optimum, mirroring glacial advances widely documented in the Alps. The Rutor Glacier advanced at ca. AD 1093 ± 65, and remained inside the LIA maximum extent. The LIA started since AD 1594, and culminated between AD 1751 and 1864.

Greening and browning of the Himalaya: Spatial patterns and the role of climatic change and human drivers

The reliable detection and attribution of changes in vegetation greenness is a prerequisite for the development of strategies for the sustainable management of ecosystems. We conducted a robust trend analysis on remote sensing derived vegetation index time-series matrices to detect significant changes in inter-annual vegetation productivity (greening versus browning) for the entire Himalaya, a biodiverse and ecologically sensitive yet understudied region. The spatial variability in trend was assessed considering elevation, 12 dominant land cover/use types and 10 ecoregions. To assess trend causation, at local scale, we compared multi-temporal imagery, and at regional scale, referenced ecological theories of mountain vegetation dynamics and ancillary literature. Overall, 17.56% of Himalayan vegetation (71,162km2) exhibited significant trend (p<0.01) and majority (94%) showed positive trend (greening). Trend distribution showed strong elevational and ecoregion dependence as greening was most dominant at lower and middle elevations whereas majority of the browning occurred at higher elevation (>3800m), with eastern high Himalaya browning more dominantly than western high Himalaya. Land cover/use based categorization confirmed dominant greening of rainfed and irrigated agricultural areas, though cropped areas in western Himalaya contained higher proportion of greening areas. While rising atmospheric CO2 concentration and nitrogen deposition are the most likely climatic causes of detected greening, success of sustainable forestry practices (community forestry in Nepal) along with increasing agricultural fertilization and irrigation facilities could be possible human drivers. Comparison of multi-temporal imagery enabled direct attribution of some browning areas to anthropogenic land change (dam, airport and tunnel construction). Our satellite detected browning of high altitude vegetation in eastern Himalaya confirm the findings of recent dendrochronology based studies which possibly resulted from reduced pre-monsoon moisture availability in recent decades. These results have significant implications for environmental management in the context of climate change and ecosystem dynamics in the Himalaya.

INTERAÇÕES PLANTA-POLINIZADOR EM VEGETAÇÃO DE ALTITUDE NA MATA ATLÂNTICA

Tropical high-altitude vegetation is unique due to susceptibility to severe weather conditions in relation to lower for­mations, and by the peculiarity of its flora with many relictual components. Studies on plant-pollinator interactions in high-altitude rocky outcrops and forests of the Atlantic Forest are scarce, but compilation of information allows us to identify some patterns: low frequency of visits, high floral longevity and generalized pollination system. In tropical mountain ecosystems, the degree of generalization of pollination systems in functional (pollinator groups) and ecological (number of species) terms tends to be high, mainly due to the over-representation of certain plant taxa (e.g., Asteraceae in rocky outcrops and Fabaceae, Myrtaceae, Rubiaceae and Sapindaceae in montane forests). Generalized pollination systems and autogamy may be advantageous for tropical high-altitude plants due to the more severe weather conditions (e.g., low temperature), which decrease abundance and limit the activity of pollinators, resulting in lower visitation frequency. Nevertheless, some well represented groups in forests, such as orchids and plants pollinated by hummingbirds and bats, exemplify cases of higher functional specialization, as well as plants with poricidal anthers pollinated by bees in the high-altitude grasslands. However, in rocky outcrops, for some functional groups of pollinators (e.g., hummingbirds, bats, beetles and hawkmoths), the availability of resources does not allow the maintenance of all species throughout the year, favoring possible local or altitudinal migrations. Thus, rocky outcrops and high-altitude forests constitute a unit in the sense of sustaining the pollinator community. Indeed ro­cky outcrops and high-altitude forests share an evolutionary history at the regional scale since they passed through similar events of expansion and retraction in response to climate changes in the Quaternary. This could explain the complementarity between the two types of vegetation in the use of floral resources by pollinators. Besides the associations identified here, the ecology and evolution of plant-pollinator interactions in high-altitude vegetation of the Atlantic Forest remain poorly understood, making urgent the development of an integrative research program, as well as projects on issues related to climate change and biodiversity conservation.

Modern and fossil pollen assemblages reveal forest taxonomic changes in the Mexican subtropics during the last 1300 years

The usual approach to reconstructing long-term vegetation dynamics is through the use of fossil pollen records from sedimentary sequences. This requires, however, an understanding of the relationship between modern pollen and the species composition and distribution on landscapes. Since different taxa produce different amounts of pollen, with different dispersal characteristics, understanding this relationship can be complex. This research aimed to address the following questions: Is it possible to distinguish different high-altitude forests by modern pollen signature? Is modern pollen abundance related to forest structure, forest diversity or to differences in altitude? How well can modern and fossil pollen assemblages reveal changes in the forest composition over the past ~1300years?Data were collected on present-day forest composition and structure and diversity, paired with modern pollen samples in three high-altitude forest types: pine forest, cloud forest and a transitional forest (a mixture of Pinus–Quercus–Carpinus) in west-central Mexico. A sediment core was collected from each vegetation type for reconstructing past vegetation. Constrained and unconstrained ordination methods were used to discern patterns of variation and the correlates behind the datasets. To compare the fossil with the modern pollen assemblages, dissimilarity indexes were computed between each of the fossil pollen sequences and their modern assemblages at different altitudes using the chord distance.Results demonstrated that each of the three forests types was distinctive in composition, and modern and fossil pollen reflected local vegetation at stand level; mean diameter and altitude were the main variables related to differences among modern pollen signatures. When reconstructing high-altitude vegetation in the subtropics, it is important to consider all taxa, even if they are rare. Therefore, in order to reveal responses to climate change and human disturbances at stand level in forests at different successional stages; particularly from 102 to 104m2 and, at temporal scales from 102 to 103years, it is essential to combine modern and fossil pollen together with present-day vegetation records.

Bison bonasus skull from the Bihor Mountains, Romania: Isotopic and morphological investigations

In this study, we investigated morphologically and geochemically a skull from an open pit situated on the Călineasa-Şesu Gârzii Plateau, Bihor Mountains. The study presents the first 14C dating and stable isotope composition of bison skeletal remains from the Romanian Carpathians. The result of 14C determination yielded two relevant maxima: one is around AD 1550 and the second around AD 1645. The data indicate that the investigated bison died during the ‘Little Ice Age’ (LIA), approximately 200 years before the last ones were hunted to extinction. Stable isotope composition of carbon from bison tooth enamel suggests that the bison diet consisted mainly of C3 grasses, compatible with a high-altitude habitat, vegetation distribution and low mobility. Oxygen isotope composition of both phosphate and carbonate groups of tooth enamel indicates that the bison drank from stagnant water sources, such as lakes or puddles formed from rain water. This further suggests low mobility of the bison as well, as the presence of such small stagnant water sources is characteristic even today for the plateau. Calculated oxygen isotope compositions of rain and drinking water at the time the bison lived indicate a lower relative humidity, around 60–70% at that period of LIA when the bison lived, which is lower than today’s humidity of 80%.

A historical ecology of the Ecrins (Southern French Alps): Archaeology and palaeoecology of the Mesolithic to the Medieval period

This paper elucidates the nature of human–environment interactions in a mountainous landscape (the southern zone of the Ecrins, French Alps) from the Mesolithic through to the Post-Medieval Period. We present an integrated programme of palynology, pedo- and archaeo-anthracology, and archaeology. These data permit the development of a historical ecology that allows us to differentiate between climatic and anthropogenic influences on vegetation, and the development of anthropogenic landscapes in an Alpine region. This study is of profound relevance for the broader understanding of human–environment interactions in ecologically sensitive environments both within the Alpine arc, but also beyond this region.We identify and explain evidence for possible human landscape management practices in a high altitude landscape. Palynology defines the broad floral context and evolution of the environment through the Holocene. Palynology also permits an assessment of human activities and practices (arable agriculture, pastoralism and haymaking). The combination of these data with anthracological and archaeological evidence permits a nuanced assessment of human interaction with the landscape. We consider phases of anthropological–ecological succession across the range of altitudes, from valley-bottom to the alpine zones in the Ecrins National Park.Four important stages of landscape use and change have been inferred from our evidence: the Mesolithic, the Chalcolithic/Bronze Age, Iron Age and Roman, and (Post)Medieval. During the Mesolithic (c. 8000–4500 BC), a major event is the expansion of fir in the montane stage. At higher altitudes, people exploit the ecotone, defined by the forest edge (or tree-line): an ideal zone for hunting. The Neolithic sees low-altitude clearances, but a continuation of hunting and low levels of human impact on high-altitude vegetation. The Chalcolithic/Bronze Age (2400–1000 BC) sees complex interplay of climatic changes, and the appearance of direct human intervention in the high altitude landscape as part of a new transhumant system. Although the Roman Period is characterised by phases of climatic amelioration after the deterioration of the Iron Age, the increase in human activity that is usually seen in low-lying areas is not reflected in the sub-alpine and alpine altitudes. The Medieval Period, including the Little Ice Age, witnesses a steady increase in human use of these landscapes, with forest manipulation and clearance becoming the defining characteristics of these areas. Despite the supposed inclement nature of the Little Ice Age, human activity achieves its zenith, and the combination people and climate produces the most open and managed landscape of the Holocene.

EL CAMBIO CLIMÁTICO Y LA DISTRIBUCIÓN ESPACIAL DE LAS FORMACIONES VEGETALES EN COLOMBIA

Vegetation change under two climate change scenarios in different periods of the 21 st Century are modeled for Colombia. Vegetation for the years 1970 to 2000 was reproduced using the Holdridge model with climate data with a spatial resolution of 900 meters. The vegetation types that occupied the most territory were sub-humid tropical forest, tropical dry forest and Andean wet forest. These results were validated by comparing with the Colombian ecosystem map (SINA, 2007), which confirmed a high degree of similarity between the modeled spatial vegetation patterns and modern ecosystem distributions. Future vegetation maps were simulated using data generated by a regional climate model under two scenarios (A2 and B2; IPCC, 2007) for the periods 2011-2040 and 2070-2100. Based on our predictions high altitude vegetation will convert to that of lower altitudes and drier provinces with the most dramatic change occurring in the A2 scenario from 2070-2100. The most affected areas are the paramo and other high Andean vegetation types, which in the timeframe of the explored scenarios will disappear by the middle of the 21 st Century.

An expert-based classification of high-altitude arctic-alpine vegetation of the class Carici rupestris-Kobresietea Ohba 1974: Achievements and obstacles

The specific species-rich high-altitude vegetation of the class Carici rupestris-Kobresietea bellardii Ohba 1974 (CK), with the occurrence of many arctic-alpine and endemic species, was chosen for a case study. The analyses were based on a dataset of 37,204 phytosociological relevés from the Slovak Vegetation Database. The traditional classification of the class CK, based on cluster analyses, was reproduced satisfactorily by means of formalised classification, based on the formal definitions created by the Cocktail method together with the frequency-positive fidelity index affiliation. Unequivocal assignment criteria for all eight associations of both alliances [Oxytropido-Elynion Br.-Bl. (1948) 1949 and Festucion versicoloris Krajina 1933] of the class CK were formulated. The formal delimitations followed the traditional ones very well. It was demonstrated that the results of applying the formal definitions created on the basis of a large, geographically stratified dataset capturing the occurrence of all vegetation types in Slovakia were highly similar in comparison with the traditional classification based on the results of cluster analysis. The reliability and the pros and cons of the expert system are also discussed.