Altitudinal evolution of vegetation on the Vercors Massif since the Late Glacial Period: new pollen data from Combe‑Chevalière (Chichilianne, Isère, 1,650 m)

Very little has been published on the shore vegetation of lakes in Colorado. Brief references were made to lakes of the Pike's Peak region a number of years ago by Clements (I, 2). A somewhat extended account by the writer and W. W. Robbins (9) described the associations at Redrock Lake, Boulder County, Colorado, in the subalpine zone. Later, a short paper (5) pointed out certain features of shore vegetation in the montane zone. Recently Dr. Robbins has given a most careful and illuminating description (ii) of a number of lakes in the montane zone near Tolland, Colorado. The present writer, dealing with sedges of northern Colorado, has named and characterized (7) certain of the plant associations of lake shores at different altitudes. In a paper by Dodds (3) on the plankton crustacea of Colorado lakes there are some references to vegetation and a very good account of physiography and climate. The following pages give the results of a study of subalpine lakes, the study carried on chiefly from the University of Colorado Mountain Laboratory (8) at Tolland, Colorado, during the last ten years. A later paper will take up alpine lakes. PHYSIOGRAPHY

The Amazon is a shelter for a huge variety of fauna and flora with the largest fluvial system and the highest diversity in the world. The biotic and abiotic factors of the floodplains serve to control the development and evolution of the ecosystems of the region. In the Amazon lowlands, little is known about past vegetation and ecosystem dynamics and to an even lesser extent human disturbances. Therefore, this project presents three palaeoecological multi-proxy studies from the western part of the Amazon region in Brazil. The aim is to reconstruct the vegetation and climate changes as well as possible human impact during the late Quaternary. A palaeoecological record from the floodplain areas of the Acre River, southwestern Brazil revealed the development and vegetation dynamics of a young oxbow lake (Lago Amapá) since the 19th century. The Lago Amapá record showed two main periods of changes. First the lake was influenced by fluvial input and afterwards the lake had a complete lacustrine phase. From ca. 1900 AD (Anno Domini) the main factors of transformation in vegetation were the fluvial dynamics, reflected by the input of sediments and pollen, transported by the river originating from Peruvian headwaters. From ca. 1950 AD the lake was rather isolated and only filled up when exceptional severe flood events occurred. Due to its close proximity to the City of Rio Branco at this time, it is assumed that the vegetation dynamics were altered by human activities. The increase of pioneer taxa, changes in sediment source and a comparison from Landsat images from the last 30 years, which showed a vast transformation in the vegetation cover close to the lake, displayed an extensive human impact. Towards the northwestern part of the Amazon region, a mid-Holocene record from a uniquely isolated plateau, the Serra do Tepequém, reflected a regional change from dry to wetter conditions, and an early expansion of the Mauritia flexuosa palm. A dry period was detected by the presence of grassland taxa, creeping pteridophytes and a high regional signal of fires between the period 7570 to 6190 cal BP (calibrated years Before Present). Subsequently, a wetter environment was detected by the changes in forest composition, reduction of grasslands and an increase on Mauritia flexuosa palm from 6190 to 4900 cal BP. In addition, the study showed that the early increase in M. flexuosa developed differently to the increase in fire and savanna expansion found in the savanna region in Venezuela The third study, a multi-proxy record from the remote region of the middle-upper Rio Negro showed the role of climate and river dynamics on the vegetation assemblages during the early and late Holocene. The Lake Acarabixi sediment core revealed that the forest was resilient to changes in the amount of precipitation and the filling dynamics of the valley of Rio Negro, which ended around 8000 cal BP in the Lake Acarabixi. In the early Holocene (10,840 to 8240 cal BP), herbs and open forest occurred, reflecting reduced precipitation with a seasonal climate. After 8240 to 1600 cal BP a large hiatus in sedimentation occurred. In the late Holocene (1600 to 650 cal BP) the lake reflected more lacustrine phases, and forest were closed with more flooding tolerant species.

Carbon dioxide (CO2) concentrations in caves and parent soils in the Italian Alps have been studied along a 2100 m altitudinal range – corresponding to a mean annual temperature (MAT) range of 12°C – in order to investigate the relationship between MAT, soil pCO2 and cave air pCO2, and to test the influence of soil pCO2 on speleothem growth and fabric to ultimately gain insight into their palaeoclimatic significance in temperate climate settings.Our findings indicate that soil CO2 is linearly correlated to MAT and its mean annual concentration is described by the equation: soil CO2 (ppmv) = 1112 + 460 MAT. Soil pCO2 can also be exponentially correlated to actual evapotranspiration. The pCO2 in the aquifer is linearly correlated to MAT at the infiltration site and is more influenced by summer soil pCO2. Cave air CO2 in the innermost part of the caves exhibits a similar seasonal pattern, and commonly reaches concentrations of about 15% to 35%, with respect to the corresponding soil values, and is exponentially correlated to the MAT at the infiltration site.The combination of these parameters (soil pCO2, dripwater pCO2 and cave air pCO2) results in speleothem growth and controls their fabrics which are typical of four MAT/elevation belts broadly corresponding to the present‐day vegetation zones. In the lower montane zone [100–800 m above sea level (a.s.l.)] speleothems mostly consist of columnar fabric, in the upper montane zone (800–1600 m a.s.l.) both columnar and dendritic fabrics are common, the Subalpine zone (1600–2200 m a.s.l.) is characterized mostly by moonmilk deposits, whereas in the Alpine zone (above 2200 m a.s.l.) no speleothems are forming today. Therefore, fabric changes in fossil speleothem can potentially be used to reconstruct MAT changes in temperate climate karst areas. Copyright © 2015 John Wiley & Sons, Ltd.

A quantitative transect analysis of altitudinal sequences of forest canopy species from 600 to 3400 m asl on Mt. Kinabalu (4101 m), Borneo, resulted in four discrete altitudinal vegetation zones. These were made up of mutually exclusive species groups for lowland (<1200 m asl), lower montane (1200 to 2000–2350 m asl), upper montane (2000–2350 to 2800 m asl), and subalpine (2800 to the forest line, 3400 m asl) zones. Zonal soil types were correlated with the vegetation zones. In upslope sequence, these were: lowland Oxisols, montane Histosol/Spodosol complex, and subalpine Inceptisols. The highest contents of organic carbon, extractable phosphorus, and exchangeable magnesium and potassium were recorded in the lower and upper montane zones. The upper boundaries of the lowland, upper montane and subalpine zones coincided with thermal thresholds of latitudinal bioclimatic zones: 18°C TMIN (Koppen's tropical), WI 85 (Kira's warm temperate), and WI 45 (Kira's cool temperate), respectively. The upper limit of the lower montane zone was correlated with an abrupt increase of water surplus estimated from the annual rainfall minus annual potential evaporation. These climatic characteristics appear to define ecological altitudinal turnover points, so called ‘critical altitudes’, where groups of associated species are displaced by other groups.

Late Holocene environmental dynamics, vegetation history, human impact, and climate change in the ancient Literna Palus (Lago Patria; Campania, Italy)

Phytoplankton assemblages in high-elevation lakes of North Cascades National Park Service Complex were studied during the open-water period in 1989. Collectively, 93 taxa were identified in 55 samples from 51 lakes. Based on cell densities, cyanobacteria had the highest relative abundance (36.7 %), followed by chlorophytes (29.8 %), and chrysophytes (19.6 %). Aphanocapsa delicatissima had the highest proportional abundance (14.0 %). Only 15.1% percent of the taxa occurred in more than 20 samples. Phytoplankton cell densities increased following a gradient of increasing lake-water temperature, alkalinity, and concentration of total Kjeldahl-N with decreasing lake elevation. Chrysophytes and cyanobacteria were quantitatively (relative abundance) the most important taxa in alpine and subalpine lakes, whereas cyanobacteria had the highest relative abundances in high-forest and low-forest lakes. Chlorophytes had their highest relative abundance in high-forest lakes. Although low in relative abundance, diatoms and dinoflagellates were most abundant in alpine lakes. An ordination by correspondence analysis indicated that most alpine, subalpine, and high-forest lakes had similar floras. Although a few subalpine lakes exhibited deviations from this pattern, the main differences in phytoplankton composition were found in a group of low-forest and high-forest lakes. Canonical correspondence analysis (CCA) provided evidence that the distribution of samples and taxa in ordination space was correlated with a gradient of decreasing lake elevation and increasing water temperature, alkalinity, and concentration of nitrogen. When CCA was used to examine relationships among phytoplankton taxa and vegetation zones, a continuous distribution of taxa was found from the low-forest zone to the subalpine zone, with a large number of taxa occurring primarily in the subalpine and high-forest zones. Three phytoplankton taxa occurred primarily in alpine lakes, whereas five taxa co-occurred in alpine, subalpine, and high forest zones. Collectively, lake elevation and associated changes in water quality and concentrations of nutrients, especially nitrogen, appeared to be the primary physical and chemical factors influencing the taxonomic structures of phytoplankton assemblages.

Palaeoecological evidence for climatic and human impacts on vegetation in the temperate deciduous forest zone of European Russia during the last 4200 years: A case study from the Kaluzhskiye Zaseki Nature Reserve

ABSTRACTHirudo verbana, a medicinal leech species of conservation concern, has long been considered rare and fragmented across its distribution range due to overexploitation and habitat alteration. In this study, we present the first predictive distribution model for H. verbana in Sicily, combining field occurrence data (time: 1980–2024) with environmental variables using an ensemble species distribution modeling (SDM) framework. Unlike its typical occurrence in temperate lowland wetlands of central‐eastern Europe, the species in Sicily shows a marked shift toward upper hill and montane zones. Species presence was strongly associated with high NDVI values, reflecting a preference for areas with dense and structurally complex vegetation. In contrast, presence probability declined sharply with increasing terrestrial human footprint (THF), indicating a notable sensitivity to anthropogenic disturbance. Aquatic habitat type also emerged as a key predictor: the species was most likely to occur in lentic environments such as standing water bodies, and least likely in lotic systems or areas lacking aquatic habitats. Notably, most high‐suitability areas overlapped with sites in the Natura 2000 network, emphasizing the importance of existing protected areas as refugia for the species. Moreover, some previously undocumented areas of high habitat suitability were identified, providing a spatially basis for refining monitoring strategies and informing conservation planning for this ecologically sensitive freshwater invertebrate.

Vegetation, climate and fire-dynamics in East Africa inferred from the Maundi crater pollen record from Mt Kilimanjaro during the last glacial–interglacial cycle

The aim of the present study was to examine soil samples from various vegetation zones in terms of physicochemical properties, microbial communities, and isolation and identification (by polymerase chain reaction and transmission electron microscopy) of bacteria producing poly-β-hydroxybutyrates (PHBs). Soil samples were analysed originating from zones with heterogeneous environmental conditions from the Romanian Carpathian Mountains (mountain zone with alpine meadow, karstic zone with limestone meadow, hill zone with xerophilous meadow, and flood plain zone with hygrophilic meadow). Different bacterial groups involved in the nitrogen cycle (aerobic mesophilic heterotrophs, ammonifiers, denitrifiers, nitrifiers, and free nitrogen-fixing bacteria from Azotobacter genus) were analysed. Soil biological quality was assessed by the bacterial indicator of soil quality, which varied between 4.3 and 4.7. A colony polymerase chain reaction technique was used for screening PHB producers. With different primers, specific bands were obtained in all the soil samples. Some wild types of Azotobacter species were isolated from the 4 studied sites. Biodegradable polymers of PHB were assessed by negative staining in transmission electron microscopy. The maximum PHB granules density was obtained in the strains isolated from the xerophilous meadow (10-18 granules/cell), which was the most stressful environment from all the studied sites, as the physicochemical and microbiological tests proved.

The Prasilske Lake is the glacial lake in the Bohemian Forest (Sumava Mts) located on theCzech side in the elevation of 1,079 m above sea level. The lake area is 4 ha, the maximal depth is 15.5 m.The lake catchment area is situated in the sub-alpine zone. The studied area has never been the object offorest or agricultural farming in the history because of its inaccessibility. The sediment dating was carriedout by means of lead isotope 210Pb. The oldest layer established by this isotope in the Prasilske Lakewas in the depth of 0.47 m. This dating was used for the deepest layer of sediment and its age was datedto the year of 1843 (depth 0.11 m) and a base of this profile to the medieval age (depth 0.47 m), whichcorresponds to about the 12th-13th century A.D. The analysed profile (0-0.47 m) can be divided into thelocal pollen assemblage zones PRI-1 (depth 0.37-0.47 m), PRI-2 (depth 0.25-0.37 m), PRI-3 (depth 0.12-0.25 m), PRI-4 (depth 0.06-0.12 m), PRI-5 (depth 0.02-0.06 m), PRI-6 (depth 0-0.02 m). On the basis ofdating by the 210Pb method the age of sediment (0-0.11 m) is established into the range of 1843 to 1994.It is noticeable in the pollen spectrum that it concerns a locality situated already above the forest border,the pollen curves of stratigraphical important taxons (mainly woody species) do not change markedly. Therich woody component is formed mainly by pollen grains of Picea and Fagus. The herbaceous component(NAP) is very diverse; however, in a general way the pollen grains of woody species (AP) predominate dueto the above mentioned deciduous forests. A representation of the herbaceous component (NAP) is veryvaried as far as species are concerned, human influence is very visible here (e.g. occurrence of cerealsCerealia, Zea mays, Fagopyrum-type, weed: Centaurea cyanus, Agrostemma githago etc.). The dating ofthis part also corresponds to the results of the pollen analysis. Of the plants producing spores the findingsof lesser clubmoss (Selaginella-type cf. Selaginella selaginoides) and water plant quillwort (Isoetes), whosenearest contemporary place of the finding in our territory is in the Cerne and Plesne Lake and Wielki Staw(the Giant Mts), were quite interesting. The most of spores were recorded at the family Polypodiaceae andgreen alga Botryococcus, which indicate cold and humid conditions of the occurrence.

Drivers of functional and phylogenetic structures of mountain bird assemblages along an altitudinal gradient from the montane to alpine zones

Populations of xerotolerant species (Achnatherum calamagrostis, Stipa crassiculmis subsp. picentina, are scattered along a wide altitudinal gradient on slopes at mid- and high elevation in Monti Picentini, a subcoastal mesozoic limestone ridge in Tyrrhenian Southern Italy. Their stands are widespread in grasslands of mostly secondary origin. At lower altitudes these grasslands replace former deciduous forest communities dominated by oaks or beech, while at higher altitudes they reach the summits, where they apparently merge into the remnants of the still partially grazed, zonal climatogenic, grasslands ranging above the local tree-line. Nevertheless primary stands of these grasslands are to be found around the many clusters of highly dynamic sites of the montane and sub-alpine levels, scattered around screes and rocky outcrops of the prevalently dolomitic morphology of the slopes. This virtual continuity of non arboreal communities across more than 1000 metres of the local topographical gradient, where azonal, relic stands of Pinus nigra s.l. are transitional between the grasslands and the surrounding zonal broadleaved forest vegetation, stresses patterns of the coenological changes between Festuco-Brometea and Elyno-Seslerietea along the catena, which suggest fragmentary persistence of a paleozonation.

The distribution and ecology of Mycena laevigata was evaluated in the Czech Republic and Slovakia. We collected data on records from 32 Czech and 32 Slovak localities, mostly from dead wood of spruce, but also fir and rarely pine. Mycena laevigata is a distinctly submontane to supramontane species with its distribution peak in the montane zone and rare occurrence in the subalpine zone. Preferred habitats are supramontane spruce forests, submontane/montane mixed forests (beech, spruce, fir) and submontane beech/fir forests. Several extrazonal habitats are known, namely waterlogged spruce forests, bog forests and ravine forests. Records of M. laevigata clearly dominate in old-growth forests under protection, which are rich in dead wood of spruce and/or fir, while records from managed forests are extremely rare. The species is able to fructify on wood of all decay stages, but most frequently at advanced stages, from May to November, with peaks in June and September. The prevailing occurrence in old-growth forests shows that the species requires not only presence of dead conifer wood in any cold and humid environment, but also some degree of habitat continuity, i.e. minor human impact on the forest ecosystem. The species can therefore be used as a good indicator of habitat preservation. Its taxonomic identity was verified molecularly using the ITS sequence from Czechia. Sequences of Asian samples are somewhat different from the European ones. Its distribution in Europe is summarised and its ecology in other parts of Europe discussed.

Cercidiphyllum japonicum and C. magnificum are deciduous tree species that produce large numbers of sprouts. They are found mainly in riparian and/or disturbed areas. C. japonicum is distributed in the montane zone in Japan, whereas C. magnificum is distributed mostly in the subalpine zone of central Japan. However, the two species sometimes coexist, e.g., on the talus slope at the valley head of the Chichibu Mountains. We investigated differences in sprouting traits in these two species by comparing class distributions of sprout diameter at breast height (DBH) and heights of individuals on the talus slope. Sprout DBH and individual height were smaller in C. magnificum as compared to C. japonicum. Moreover, the analysis of the DBH-class distribution of each species indicated that C. magnificum had numerous small sprouts and experienced high mortality, whereas C. japonicum had fewer small sprouts and low mortality. It is likely that the sprouting traits of C. magnificum make it more adapted to severe conditions in the subalpine zone than those of C. japonicum.