Journal articles: 'Montane Ecosystems'

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Khuroo, Anzar A., Zafar Reshi, Irfan Rashid, GH Dar, and Akhtar H. Malik. "Plant invasions in montane ecosystems." Frontiers in Ecology and the Environment 7, no. 8 (October 2009): 408. http://dx.doi.org/10.1890/09.wb.027.

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Poole, Kim G., Robert Serrouya, and Kari Stuart-Smith. "Moose Calving Strategies in Interior Montane Ecosystems." Journal of Mammalogy 88, no. 1 (February 28, 2007): 139–50. http://dx.doi.org/10.1644/06-mamm-a-127r1.1.

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Gotsch, Sybil G., Heidi Asbjornsen, and Gregory R. Goldsmith. "Plant carbon and water fluxes in tropical montane cloud forests." Journal of Tropical Ecology 32, no. 5 (July 15, 2016): 404–20. http://dx.doi.org/10.1017/s0266467416000341.

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Abstract:Tropical montane cloud forests (TMCFs) are dynamic ecosystems defined by frequent, but intermittent, contact with fog. The resultant microclimate can vary considerably over short spatial and temporal scales, affecting the ecophysiology of TMCF plants. We synthesized research to date on TMCF carbon and water fluxes at the scale of the leaf, plant and ecosystem and then contextualized this synthesis with tropical lowland forest ecosystems. Mean light-saturated photosynthesis was lower than that of lowland forests, probably due to the effects of persistent reduced radiation leading to shade acclimation. Scaled to the ecosystem, measures of annual net primary productivity were also lower. Mean rates of transpiration, from the scale of the leaf to the ecosystem, were also lower than in lowland sites, likely due to lower atmospheric water demand, although there was considerable overlap in range. Lastly, although carbon use efficiency appears relatively invariant, limited evidence indicates that water use efficiency generally increases with altitude, perhaps due to increased cloudiness exerting a stronger effect on vapour pressure deficit than photosynthesis. The results reveal clear differences in carbon and water balance between TMCFs and their lowland counterparts and suggest many outstanding questions for understanding TMCF ecophysiology now and in the future.

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Bax, Vincent, Augusto Castro-Nunez, and Wendy Francesconi. "Assessment of Potential Climate Change Impacts on Montane Forests in the Peruvian Andes: Implications for Conservation Prioritization." Forests 12, no. 3 (March 21, 2021): 375. http://dx.doi.org/10.3390/f12030375.

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Future climate change will result in profound shifts in the distribution and abundance of biodiversity in the Tropical Andes, and poses a challenge to contemporary conservation planning in the region. However, currently it is not well understood where the impacts of climate disruption will be most severe and how conservation policy should respond. This study examines climate change impacts in the Peruvian Andes, with a specific focus on tropical montane forest ecosystems, which are particularly susceptible to climate change. Using an ensemble of classification models coupled with different climate change scenarios, we estimate high and low potential impacts on montane forest, by projecting which areas will become climatically unsuitable to support montane forest ecosystems by 2070. These projections are subsequently used to examine potential impacts on protected areas containing montane forest. The modeling output indicates that climate change will have a high potential impact on 58% of all montane forests, particularly in the elevation range between 800 and 1200 m.a.s.l. Furthermore, about 64% of montane forests located in protected areas will be exposed to high potential impact. These results highlight the need for Peru’s conservation institutions to incorporate climate change considerations into prevailing conservation plans and adaptation strategies. To adjust to climate change, the adaptive capacity of forest ecosystems in the Peruvian Andes should be enhanced through restorative and preventive conservation measures such as improving forest functions and mitigating deforestation and forest degradation pressures.

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Baumgartner, Simon, Matti Barthel, Travis William Drake, Marijn Bauters, Isaac Ahanamungu Makelele, John Kalume Mugula, Laura Summerauer, et al. "Seasonality, drivers, and isotopic composition of soil CO<sub>2</sub> fluxes from tropical forests of the Congo Basin." Biogeosciences 17, no. 23 (December 9, 2020): 6207–18. http://dx.doi.org/10.5194/bg-17-6207-2020.

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Abstract. Soil respiration is an important carbon flux and key process determining the net ecosystem production of terrestrial ecosystems. To address the lack of quantification and understanding of seasonality in soil respiration of tropical forests in the Congo Basin, soil CO2 fluxes and potential controlling factors were measured annually in two dominant forest types (lowland and montane) of the Congo Basin over 2 years at varying temporal resolution. Soil CO2 fluxes from the Congo Basin resulted in 3.45 ± 1.14 and 3.13 ± 1.22 µmol CO2 m−2 s−1 for lowland and montane forests, respectively. Soil CO2 fluxes in montane forest soils showed a clear seasonality with decreasing flux rates during the dry season. Montane forest soil CO2 fluxes were positively correlated with soil moisture, while CO2 fluxes in the lowland forest were not. Smaller differences of δ13C values of leaf litter, soil organic carbon (SOC), and soil CO2 indicated that SOC in lowland forests is more decomposed than in montane forests, suggesting that respiration is controlled by C availability rather than environmental factors. In general, C in montane forests was more enriched in 13C throughout the whole cascade of carbon intake via photosynthesis, litterfall, SOC, and soil CO2 compared to lowland forests, pointing to a more open system. Even though soil CO2 fluxes are similarly high in lowland and montane forests of the Congo Basin, the drivers of them seem to be different, i.e., soil moisture for montane forest and C availability for lowland forest.

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Aparecido, Luiza Maria T., Grazielle S. Teodoro, Giovanny Mosquera, Mauro Brum, Fernanda de V. Barros, Patricia Vieira Pompeu, Melissa Rodas, et al. "Ecohydrological drivers of Neotropical vegetation in montane ecosystems." Ecohydrology 11, no. 3 (January 12, 2018): e1932. http://dx.doi.org/10.1002/eco.1932.

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Robinson, Wayne, and Diane Debinski. "Epigaeic Ant Communities Along a Soil Moisture Gradient in Grand Teton Montane Meadows." UW National Parks Service Research Station Annual Reports 31 (January 1, 2008): 135–40. http://dx.doi.org/10.13001/uwnpsrc.2008.3727.

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Climate change has become a major concern for scientists and resource managers across the globe. Whilst there is much speculation about the pending magnitude of the changes and their ecological effects, there is an urgent and undeniable need to have sound ecological monitoring programs in place in sensitive areas. Montane meadows in the Greater Yellowstone Ecosystem (GYE) are inhabited by short-lived plants and highly mobile animal species that can exhibit quick changes in distribution patterns relative to environmental changes (Debinski et al. 2000, Debinski et al. 2002). Thus, they can provide an early warning system for other ecosystems across the globe. Currently, the extent and range of climatic changes that will occur in montane meadows are unknown.

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Huesca, Margarita, Keely L. Roth, Mariano García, and Susan L. Ustin. "Discrimination of Canopy Structural Types in the Sierra Nevada Mountains in Central California." Remote Sensing 11, no. 9 (May 8, 2019): 1100. http://dx.doi.org/10.3390/rs11091100.

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Accurate information about ecosystem structure and biogeochemical properties is essential to providing better estimates ecosystem functioning. Airborne LiDAR (light detection and ranging) is the most accurate way to retrieve canopy structure. However, accurately obtaining both biogeochemical traits and structure parameters requires concurrent measurements from imaging spectrometers and LiDARs. Our main objective was to evaluate the use of imaging spectroscopy (IS) to provide vegetation structural information. We developed models to estimate structural variables (i.e., biomass, height, vegetation heterogeneity and clumping) using IS data with a random forests model from three forest ecosystems (i.e., an oak-pine low elevation savanna, a mixed conifer/broadleaf mid-elevation forest, and a high-elevation montane conifer forest) in the Sierra Nevada Mountains, California. We developed and tested general models to estimate the four structural variables with accuracies greater than 75%, for the structurally and ecologically different forest sites, demonstrating their applicability to a diverse range of forest ecosystems. The model R2 for each structural variable was least in the conifer/broadleaf forest than either the low elevation savanna or the montane conifer forest. We then used the structural variables we derived to discriminate site-specific, ecologically meaningful descriptions of canopy structural types (CST). Our CST results demonstrate how IS data can be used to create comprehensive and easily interpretable maps of forest structural types that capture their major structural features and trends across different vegetation types in the Sierra Nevada Mountains. The mixed conifer/broadleaf forest and montane conifer forest had the most complex structures, containing six and five CSTs respectively. The identification of CSTs within a site allowed us to better identify the main drivers of structural variability in each ecosystem. CSTs in open savanna were driven mainly by differences in vegetation cover; in the mid-elevation mixed forest, by the combination of biomass and canopy height; and in the montane conifer forest, by vegetation heterogeneity and clumping.

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Shen, Ju-Pei, Maryam Esfandbod, Steve A. Wakelin, Gary Bacon, Qiaoyun Huang, and Chengrong Chen. "Changes in bacterial community composition across natural grassland and pine forests in the Bunya Mountains in subtropical Australia." Soil Research 57, no. 8 (2019): 825. http://dx.doi.org/10.1071/sr19111.

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Tree and grass species coexist in many ecosystems worldwide and support multiple ecosystem functions and services. However, the distribution of bacterial communities and factors driving coexistence in tree–grass associations and their ecosystem functions remain poorly understood. In this study, the distribution of soil bacteria and their link to changes in abiotic factors were investigated in adjacent montane grassland (C4 plants) and pine forest (bunya pine and hoop pine; C3 plants) sites in the Bunya Mountains, subtropical Australia. Different vegetation (grassy balds and forest) had a substantial effect on terrestrial ecosystem properties, with higher levels of soil nutrients (e.g. total nitrogen (N), total phosphorus (P)) and electrical conductivity (EC), and lower δ13C values and pH under forests compared with grassland. Bacterial α-diversity (total species per operational taxonomic unit richness) did not differ between grassland and pine forest sites, whereas strong shifts in the bacterial community composition and structure were evident. Patterns in bacterial community structure were strongly associated with changes in soil pH, EC, total P and δ13C. Different bacterial groups associated with pine forest (Gammaproteobacteria and Alphaproteobacteria) and grassland (Acidobacteria and Verrucomicrobia) were identified as key groups contributing to the segregation of these two ecosystems in the Bunya Mountains. These findings suggest that heterogeneity in soil edaphic properties (e.g. key nutrients) likely contributed to variation in bacterial β-diversity of grassland and pine forest, which has potential implications for species coexistence and ecosystem function in montane eastern Australia.

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Morris, Jesse L., R. Justin DeRose, Thomas Brussel, Simon Brewer, Andrea Brunelle, and James N. Long. "Stable or seral? Fire-driven alternative states in aspen forests of western North America." Biology Letters 15, no. 6 (June 2019): 20190011. http://dx.doi.org/10.1098/rsbl.2019.0011.

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As important centres for biological diversity, aspen forests are essential to the function and aesthetics of montane ecosystems in western North America. Aspen stands are maintained by a nuanced relationship with wildfire, although in recent decades aspen mortality has increased. The need to understand the baseline environmental conditions that favour aspen is clear; however, long-term fire history reconstructions are rare due to the scarcity of natural archives in dry montane settings. Here, we analyse a high-resolution lake sediment record from southwestern, Utah, USA to quantify the compositional and burning conditions that promote stable (or seral) aspen forests. Our results show that aspen presence is negatively correlated with subalpine fir and that severe fires tend to promote persistent and diverse aspen ecosystems over centennial timescales. This information improves our understanding of aspen disturbance ecology and identifies the circumstances where critical transitions in montane forests may occur.

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Velandia-Perilla, Jorge Horacio, and Carlos Arturo Saavedra-Rodríguez. "Mammalia, Rodentia, Cricetidae, Neusticomys monticolus (Anthony, 1921): noteworthy records of the Montane Fish- Eating Rat in Colombia." Check List 9, no. 3 (June 1, 2013): 686. http://dx.doi.org/10.15560/9.3.686.

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We document the presence of the Montane Fish-eating Rat, Neusticomys monticolus, in two páramo ecosystems of the Colombian Andes, in the departments of Valle del Cauca and Cauca at 3558 and 3300 m respectively. For small mammals, páramo ecosystems are underexplored zones in a biogeographic context.

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Parajuli, Kshitij, Scott B. Jones, David G. Tarboton, Gerald N. Flerchinger, Lawrence E. Hipps, L. Niel Allen, and Mark S. Seyfried. "Estimating actual evapotranspiration from stony-soils in montane ecosystems." Agricultural and Forest Meteorology 265 (February 2019): 183–94. http://dx.doi.org/10.1016/j.agrformet.2018.11.019.

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Abril, Adriana B., and Enrique H. Bucher. "Variation in soil biological characteristics on an elevational gradient in the montane forest of north-west Argentina." Journal of Tropical Ecology 24, no. 4 (July 2008): 457–61. http://dx.doi.org/10.1017/s0266467408005154.

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Montane tropical and subtropical rain forests are complex ecosystems, characterized by marked rainfall and temperature gradients with altitude, which in turn control the vegetation altitudinal zones (Hueck 1978). Montane forests are often referred to as cloud forests in recognition of the important influence of a dense and frequent cloud cover that conditions forest structure and functioning (Bautista-Cruz & del Castillo 2005, Holder 2004).

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Jolli, V. "Hydro Power Development and Its Impacts on the Habitats and Diversity of Montane Birds of Western Himalayas." Vestnik Zoologii 51, no. 4 (August 28, 2017): 311–24. http://dx.doi.org/10.1515/vzoo-2017-0036.

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Abstract The montane forest ecosystems of Western Himalayas are under severe anthropogenic pressure because of hydro-electric project (HEP) development. Several studies have highlighted downstream effects of HEP, but there is no information on the effects of HEP-building activities on upstream fauna. In particular, studies on upstream Himalayan montane ecosystems and fauna around dams are lacking. I investigated effects of dam-building activities on bird communities in Indian Western Himalayas. I studied the response of bird communities along a disturbance gradient with the aim to identify key factors influencing their distribution. I surveyed primary and secondary montane forests, agricultural lands, and dam-affected (disturbed) habitats. Response variables included total avifaunal and woodland species richness and abundance, which were estimated by point-count surveys. Explanatory variables included tree and shrub density, canopy cover, disturbance intensity, and elevation. Bird species richness was higher in undisturbed and lesser disturbed sites, lower in agricultural sites, and lowest in HEP-affected sites. Canonical correspondence analysis revealed that canopy cover, shrub density, and disturbance influenced species distribution; woodland birds significantly negatively responded to dam-building activities. Th e study has shown that dam-building activity has negatively affected montane birds. I propose that increasing shrub and tree cover in dam-disturbed sites would minimise losses of avian habitats.

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Rodríguez-Echeverry, James, and Margareth Leiton. "State of the Landscape and Dynamics of Loss and Fragmentation of Forest Critically Endangered in the Tropical Andes Hotspot: Implications for Conservation Planning." Journal of Landscape Ecology 14, no. 1 (May 1, 2021): 73–91. http://dx.doi.org/10.2478/jlecol-2021-0005.

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Abstract Currently, there is no precise information on the degree of transformation of Tropical Andes hotspot landscape and native ecosystems due to the intensification of agricultural and urban land-use. Proper knowledge of these changes would provide crucial information for planning conservation strategies. We evaluated the impact of the intensification of agricultural and urban land-use on the Inter-Andean Dry Forest and Tropical Montane Forest, both of which are categorized as Critically Endangered, and the state of the landscape in the High Rio Guayllabamba watershed, Ecuador, during the periods 1991–2005 and 2005–2017. The evaluation was carried out using Landsat satellite images of 30 x 30 m pixels and landscape metrics. We found an advanced state of landscape transformation. Since the 1990s, the loss of both ecosystems was largely caused by the conversion of forest to agriculture, resulting in substantial changes in the spatial configuration of these ecosystems. From 1991 to 2017, 19.8 % and 16.1 % of Inter-Andean Dry Forest and Tropical Montane Forest respectively, were converted to agriculture. The loss of Inter-Andean Dry Forest was 28 % and the number of forest patches increased by more than 150%. The loss of Tropical Montane Forest was 16.5 % and the number of forest patches increased by more than 300 %. The largest loss and fragmentation of forest cover occurred from 1991 to 2005. We suggested planning landscape-scale conservation, using the patch-corridor-matrix model. This model is appropriate given the current configuration of the landscape studied, with Inter-Andean Dry Forest and Tropical Montane Forest restricted to small patches sparsely distributed across the landscape.

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Hooghiemstra, Henry. "Geoecology of little-explored neotropical montane ecosystems: a monumental work." Journal of Biogeography 32, no. 10 (October 2005): 1855–56. http://dx.doi.org/10.1111/j.1365-2699.2005.01303.x.

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Kaasalainen, Ulla, Veera Tuovinen, Paul M. Kirika, Neduvoto P. Mollel, Andreas Hemp, and Jouko Rikkinen. "Diversity of Leptogium (Collemataceae, Ascomycota) in East African Montane Ecosystems." Microorganisms 9, no. 2 (February 3, 2021): 314. http://dx.doi.org/10.3390/microorganisms9020314.

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Tropical mountains and especially their forests are hot spots of biodiversity threatened by human population pressure and climate change. The diversity of lichens in tropical Africa is especially poorly known. Here we use the mtSSU and nuITS molecular markers together with morphology and ecology to assess Leptogium (Peltigerales, Ascomycota) diversity in the tropical mountains of Taita Hills and Mt. Kasigau in Kenya and Mt. Kilimanjaro in Tanzania. The sampled habitats cover a wide range of ecosystems from savanna to alpine heath vegetation and from relatively natural forests to agricultural environments and plantation forests. We demonstrate that Leptogium diversity in Africa is much higher than previously known and provide preliminary data on over 70 putative species, including nine established species previously known from the area and over 60 phylogenetically, morphologically, and/or ecologically defined Operational Taxonomic Units (OTUs). Many traditional species concepts are shown to represent morphotypes comprised of several taxa. Many of the species were only found from specific ecosystems and/or restricted habitats and are thus threatened by ongoing habitat fragmentation and degradation of the natural environment. Our results emphasize the importance of molecular markers in species inventories of highly diverse organism groups and geographical areas.

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Diem, Torsten, Nicholas J. Morley, Adan Julian Ccahuana Quispe, Lidia Priscila Huaraca Quispe, Elizabeth M. Baggs, Patrick Meir, Mark I. A. Richards, Pete Smith, and Yit Arn Teh. "Complex controls on nitrous oxide flux across a large-elevation gradient in the tropical Peruvian Andes." Biogeosciences 14, no. 22 (November 15, 2017): 5077–97. http://dx.doi.org/10.5194/bg-14-5077-2017.

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Abstract. Current bottom–up process models suggest that montane tropical ecosystems are weak atmospheric sources of N2O, although recent empirical studies from the southern Peruvian Andes have challenged this idea. Here we report N2O flux from combined field and laboratory experiments that investigated the process-based controls on N2O flux from montane ecosystems across a large-elevation gradient (600–3700 m a.s.l.) in the southern Peruvian Andes. Nitrous oxide flux and environmental variables were quantified in four major habitats (premontane forest, lower montane forest, upper montane forest and montane grassland) at monthly intervals over a 30-month period from January 2011 to June 2013. The role of soil moisture content in regulating N2O flux was investigated through a manipulative, laboratory-based 15N-tracer experiment. The role of substrate availability (labile organic matter, NO3−) in regulating N2O flux was examined through a field-based litter-fall manipulation experiment and a laboratory-based 15N–NO3− addition study, respectively. Ecosystems in this region were net atmospheric sources of N2O, with an unweighted mean flux of 0.27 ± 0.07 mg N–N2O m−2 d−1. Weighted extrapolations, which accounted for differences in land surface area among habitats and variations in flux between seasons, predicted a mean annual flux of 1.27 ± 0.33 kg N2O–N ha−1 yr−1. Nitrous oxide flux was greatest from premontane forest, with an unweighted mean flux of 0.75 ± 0.18 mg N–N2O m−2 d−1, translating to a weighted annual flux of 0.66 ± 0.16 kg N2O–N ha−1 yr−1. In contrast, N2O flux was significantly lower in other habitats. The unweighted mean fluxes for lower montane forest, montane grasslands, and upper montane forest were 0.46 ± 0.24 mg N–N2O m−2 d−1, 0.07 ± 0.08 mg N–N2O m−2 d−1, and 0.04 ± 0.07 mg N–N2O m−2 d−1, respectively. This corresponds to weighted annual fluxes of 0.52 ± 0.27 kg N2O–N ha−1 yr−1, 0.05 ± 0.06 kg N2O–N ha−1 yr−1, and 0.04 ± 0.07 kg N2O–N ha−1 yr−1, respectively. Nitrous oxide flux showed weak seasonal variation across the region; only lower montane forest showed significantly higher N2O flux during the dry season compared to wet season. Manipulation of soil moisture content in the laboratory indicated that N2O flux was significantly influenced by changes in water-filled pore space (WFPS). The relationship between N2O flux and WFPS was complex and non-linear, diverging from theoretical predictions of how WFPS relates to N2O flux. Nitrification made a negligible contribution to N2O flux, irrespective of soil moisture content, indicating that nitrate reduction was the dominant source of N2O. Analysis of the pooled data indicated that N2O flux was greatest at 90 and 50 % WFPS, and lowest at 70 and 30 % WFPS. This trend in N2O flux suggests a complex relationship between WFPS and nitrate-reducing processes (i.e. denitrification, dissimilatory nitrate reduction to ammonium). Changes in labile organic matter inputs, through the manipulation of leaf litter-fall, did not alter N2O flux. Comprehensive analysis of field and laboratory data demonstrated that variations in NO3− availability strongly constrained N2O flux. Habitat – a proxy for NO3− availability under field conditions – was the best predictor for N2O flux, with N-rich habitats (premontane forest, lower montane forest) showing significantly higher N2O flux than N-poor habitats (upper montane forest, montane grassland). Yet, N2O flux did not respond to short-term changes in NO3− concentration.

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Teh, Y. A., T. Diem, S. Jones, L. P. Huaraca Quispe, E. Baggs, N. Morley, M. Richards, P. Smith, and P. Meir. "Methane and nitrous oxide fluxes from the tropical Andes." Biogeosciences Discussions 10, no. 11 (November 5, 2013): 17397–438. http://dx.doi.org/10.5194/bgd-10-17397-2013.

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Abstract. Remote sensing and inverse modelling studies indicate that the tropics emit more CH4 and N2O than predicted by bottom-up emissions inventories, suggesting that terrestrial sources are stronger or more numerous than previously thought. Tropical uplands are a potentially large and important source of CH4 and N2O often overlooked by past empirical and modelling studies. To address this knowledge gap, we investigated spatial, temporal and environmental trends in CH4 and N2O fluxes across a~long elevation gradient (600–3700 m a.s.l.) in the Kosñipata Valley, in the southern Peruvian Andes that experiences seasonal fluctuations in rainfall. The aim of this work was to produce preliminary estimates of CH4 and N2O fluxes from representative habitats within this region, and to identify the proximate controls on soil CH4 and N2O dynamics. Ecosystems across this altitudinal gradient were both atmospheric sources and sinks of CH4 on an annual basis. Montane grasslands (or, puna; 3200–3700 m a.s.l.) were strong atmospheric sources, emitting 56.94 ± 7.81kg CH4-C ha−1 yr−1. Upper montane forest (2200–3200 m a.s.l.) and lower montane forest (1200–2200 m a.s.l.) were net atmospheric sinks (−2.99 ± 0.29 kg CH4-C ha−1 yr−1 and −2.34 ± 0.29 kg CH4-C ha−1 yr−1, respectively); while premontane forests (600–1200 m a.s.l.) fluctuated between source or sink depending on the season (wet season: 1.86 ± 1.50 CH4-C ha−1 yr−1; dry season: −1.17 ± 0.40 CH4-C ha−1 yr−1). Analysis of spatial, temporal and environmental trends in CH4 flux across the study site suggest that soil redox was a dominant control on net CH4 flux. CH4 emissions were greatest from elevations, landforms and during times of year when soils were sub-oxic, and CH4 efflux was inversely correlated with soil O2 concentration (r2 = 0.82, F1, 125 = 588.41, P < 0.0001). Ecosystems across the region were net atmospheric N2O sources. N2O fluxes declined with increasing elevation; N2O emissions from premontane forest, lower montane forest, upper montane forest and montane grasslands averaged 2.23 ± 1.31 kg N2O-N ha−1 yr−1, 1.68 ± 0.44 kg N2O-N ha−1 yr−1, 0.44 ± 0.47 kg N2O-N ha−1 yr−1 and 0.15 ± 1.10 kg N2O-N ha−1 yr−1, respectively. N2O fluxes from premontane and lower montane forests exceeded prior model predictions for the region. Comprehensive investigation of field and laboratory data collected in this study suggest that N2O fluxes from this region were primarily driven by denitrification; that nitrate (NO3−) availability was the principal constraint on N2O fluxes; and that soil moisture and water-filled porosity played a secondary role in modulating N2O emissions. Any current and future changes in N management or anthropogenic N deposition may cause shifts in net N2O fluxes from these tropical montane ecosystems, further enhancing this emission source.

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Marín, Franklin, Carlos Dahik, Giovanny Mosquera, Jan Feyen, Pedro Cisneros, and Patricio Crespo. "Changes in Soil Hydro-Physical Properties and SOM Due to Pine Afforestation and Grazing in Andean Environments Cannot Be Generalized." Forests 10, no. 1 (December 29, 2018): 17. http://dx.doi.org/10.3390/f10010017.

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Andean ecosystems provide important ecosystem services including streamflow regulation and carbon sequestration, services that are controlled by the water retention properties of the soils. Even though these soils have been historically altered by pine afforestation and grazing, little research has been dedicated to the assessment of such impacts at local or regional scales. To partially fill this knowledge gap, we present an evaluation of the impacts of pine plantations and grazing on the soil hydro-physical properties and soil organic matter (SOM) of high montane forests and páramo in southern Ecuador, at elevations varying between 2705 and 3766 m a.s.l. In total, seven study sites were selected and each one was parceled into undisturbed and altered plots with pine plantation and grazing. Soil properties were characterized at two depths, 0–10 and 10–25 cm, and differences in soil parameters between undisturbed and disturbed plots were analyzed versus factors such as ecosystem type, sampling depth, soil type, elevation, and past/present land management. The main soil properties affected by land use change are the saturated hydraulic conductivity (Ksat), the water retention capacity (pF 0 to 2.52), and SOM. The impacts of pine afforestation are dependent on sampling depth, ecosystem type, plantation characteristics, and previous land use, while the impacts of grazing are primarily dependent on sampling depth and land use management (grazing intensity and tilling activities). The site-specific nature of the found relations suggests that extension of findings in response to changes in land use in montane Andean ecosystems is risky; therefore, future evaluations of the impact of land use change on soil parameters should take into consideration that responses are or can be site specific.

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Garcés-Pastor, Sandra, Núria Cañellas-Boltà, Albert Clavaguera, Miguel Angel Calero, and Teresa Vegas-Vilarrúbia. "Vegetation shifts, human impact and peat bog development in Bassa Nera pond (Central Pyrenees) during the last millennium." Holocene 27, no. 4 (November 11, 2016): 553–65. http://dx.doi.org/10.1177/0959683616670221.

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High-mountain lakes are suitable ecosystems for studying local environmental shifts driven by large-scale climate changes, with potential applications to predict future scenarios. The precise features in the response of species assemblages are not fully understood, and human pressure may often hide climatic signals. To investigate the origin and impact of past environmental changes in high-mountain ecosystems and apply this palaeoecological knowledge to anticipate future changes, we performed a multi-proxy study of a sediment core from Bassa Nera, a pond located close to montane–subalpine ecotone in the southern central Pyrenees. Combining pollen and diatom analysis at multidecadal resolution, we inferred vegetation shifts and peat bog development during the past millennium. We introduced a montane pollen ratio as a new palaeoecological indicator of altitudinal shifts in vegetation. Our results emphasize the sensitivity of the montane ratio to detect upward migrations of deciduous forest and the presence of the montane belt close to Bassa Nera pond during the Medieval Climate Anomaly. Changes in aquatic taxa allowed to date the onset of the surrounding peat bog which appeared and infilled the coring site around AD 1565. Overall, our results suggest a low-intensity human pressure and changes in management of natural resources during the last millennium, where farming was the main activity from the Medieval Climate Anomaly until AD 1500. Afterwards, people turned to highland livestock raising coinciding with the ‘Little Ice Age’.

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Hamilton, Natalia P., Stephanie G. Yelenik, Tara D. Durboraw, Robert D. Cox, and Nathan S. Gill. "Understanding Grass Invasion, Fire Severity, and Acacia koa Regeneration for Forest Restoration in Hawaiʻi Volcanoes National Park." Land 10, no. 9 (September 10, 2021): 962. http://dx.doi.org/10.3390/land10090962.

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With invasive grasses increasing wildfire occurrence worldwide, a better understanding of the relationships between native plants, fire, and invasive grass is needed to help restoration plans facilitate ecosystem resilience. Invasive grasses are particularly problematic for altering fire regimes in the tropics, yet in Hawaiʻi, restoration sites are often planted with monocultures of the native tree Acacia koa, which can promote grass growth via nitrogen fixation. This, combined with the difficulty of estimating pre-fire grass cover under thick canopies, complicates attempts to restore Hawaiian ecosystems. We studied the 2018 Keauhou Ranch Fire in Hawaiʻi to investigate three questions: (1) at what level of precision can pre-fire grass cover be accurately estimated from oblique aerial photos? (2) how are post-fire A. koa regeneration densities affected by fire severity? and (3) how are post-fire A. koa regeneration densities affected by pre-fire grass cover and its interaction with fire severity? We collected burn severity and post-fire regeneration data from 30 transects stratified across mid-elevation woodland, montane woodland, and montane shrubland communities. We evaluated visual estimates of pre-fire grass cover from oblique aerial imagery with quantitative in situ data from 60 unburned transects of the same cover types. Pre-fire estimates of grass cover categories were 67% accurate in montane woodland (n = 9) and 100% accurate in montane shrubland (n = 11), but only 20% accurate in mid-elevation woodland (n = 10). In montane woodlands with low pre-fire tree densities, A. koa regeneration densities were higher with increased fire severity, but this trend reversed when pre-fire tree densities were high. We detected no effect of pre-fire grass cover, nor its interaction with fire severity, on A. koa regeneration density. This indicates that restoration through the planting of A. koa may be successful in promoting fire-resilient A. koa forest, although there are potential issues to consider regarding the effects that A. koa’s grass promotion may have on other species within the ecosystem.

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Whittier, Thomas R., Robert M. Hughes, and David P. Larsen. "Correspondence Between Ecoregions and Spatial Patterns in Stream Ecosystems in Oregon." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 7 (July 1, 1988): 1264–78. http://dx.doi.org/10.1139/f88-149.

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Multivariate analyses of biotic assemblages and physicochemical measures, species richness, diversity, and composition were used to evaluate the robustness of Omernik's ecoregion classification for small streams in the eight ecoregions of Oregon. Clearest differences were between the montane and nonmontane regions. For the three nonmontane regions, ordinations of fishes, macroinvertebrates, water quality, and physical habitat measures show the clearest differences, with the Willamette Valley ecoregion being consistently most unlike all other regions. Differences between the Columbia Basin and High Desert regions were clearest for water quality and physical habitat measures and fish assemblages. Differences among the montane regions were subtle. Of these regions, the East Cascade Slopes showed the greatest variability, as shown by the ranges of ordination scores for fishes, water quality, and physical habitat. Regional patterns in periphyton assemblages were markedly different from the patterns in the other groups of variables. Ecoregions can be used as a broad-scale geographic framework for classifying streams. This framework provides managers of lotic resources a useful alternative to river basins.

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Teh, Y. A., T. Diem, S. Jones, L. P. Huaraca Quispe, E. Baggs, N. Morley, M. Richards, P. Smith, and P. Meir. "Methane and nitrous oxide fluxes across an elevation gradient in the tropical Peruvian Andes." Biogeosciences 11, no. 8 (April 25, 2014): 2325–39. http://dx.doi.org/10.5194/bg-11-2325-2014.

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Abstract. Remote sensing and inverse modelling studies indicate that the tropics emit more CH4 and N2O than predicted by bottom-up emissions inventories, suggesting that terrestrial sources are stronger or more numerous than previously thought. Tropical uplands are a potentially large and important source of CH4 and N2O often overlooked by past empirical and modelling studies. To address this knowledge gap, we investigated spatial, temporal and environmental trends in soil CH4 and N2O fluxes across a long elevation gradient (600–3700 m a.s.l.) in the Kosñipata Valley, in the southern Peruvian Andes, that experiences seasonal fluctuations in rainfall. The aim of this work was to produce preliminary estimates of soil CH4 and N2O fluxes from representative habitats within this region, and to identify the proximate controls on soil CH4 and N2O dynamics. Area-weighted flux calculations indicated that ecosystems across this altitudinal gradient were both atmospheric sources and sinks of CH4 on an annual basis. Montane grasslands (3200–3700 m a.s.l.) were strong atmospheric sources, emitting 56.94 ± 7.81 kg CH4-C ha−1 yr−1. Upper montane forest (2200–3200 m a.s.l.) and lower montane forest (1200–2200 m a.s.l.) were net atmospheric sinks (−2.99 ± 0.29 and −2.34 ± 0.29 kg CH4-C ha−1 yr−1, respectively); while premontane forests (600–1200 m a.s.l.) fluctuated between source or sink depending on the season (wet season: 1.86 ± 1.50 kg CH4-C ha−1 yr−1; dry season: −1.17 ± 0.40 kg CH4-C ha−1 yr−1). Analysis of spatial, temporal and environmental trends in soil CH4 flux across the study site suggest that soil redox was a dominant control on net soil CH4 flux. Soil CH4 emissions were greatest from habitats, landforms and during times of year when soils were suboxic, and soil CH4 efflux was inversely correlated with soil O2 concentration (Spearman's ρ = −0.45, P < 0.0001) and positively correlated with water-filled pore space (Spearman's ρ = 0.63, P <0.0001). Ecosystems across the region were net atmospheric N2O sources. Soil N2O fluxes declined with increasing elevation; area-weighted flux calculations indicated that N2O emissions from premontane forest, lower montane forest, upper montane forest and montane grasslands averaged 2.23 ± 1.31, 1.68 ± 0.44, 0.44 ± 0.47 and 0.15 ± 1.10 kg N2O-N ha−1 yr−1, respectively. Soil N2O fluxes from premontane and lower montane forests exceeded prior model predictions for the region. Comprehensive investigation of field and laboratory data collected in this study suggest that soil N2O fluxes from this region were primarily driven by denitrification; that nitrate (NO3−) availability was the principal constraint on soil N2O fluxes; and that soil moisture and water-filled porosity played a secondary role in modulating N2O emissions. Any current and future changes in N management or anthropogenic N deposition may cause shifts in net soil N2O fluxes from these tropical montane ecosystems, further enhancing this emission source.

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Boggs, Carol L., and Dennis D. Murphy. "Community Composition in Mountain Ecosystems: Climatic Determinants of Montane Butterfly Distributions." Global Ecology and Biogeography Letters 6, no. 1 (January 1997): 39. http://dx.doi.org/10.2307/2997525.

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Arvin, Lindsay J., Clifford S. Riebe, Sarah M. Aciego, and Molly A. Blakowski. "Global patterns of dust and bedrock nutrient supply to montane ecosystems." Science Advances 3, no. 12 (December 2017): eaao1588. http://dx.doi.org/10.1126/sciadv.aao1588.

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Mao, Zhun, Franck Bourrier, Alexia Stokes, and Thierry Fourcaud. "Three-dimensional modelling of slope stability in heterogeneous montane forest ecosystems." Ecological Modelling 273 (February 2014): 11–22. http://dx.doi.org/10.1016/j.ecolmodel.2013.10.017.

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Lofroth, Eric C., John A. Krebs, William L. Harrower, and Dave Lewis. "Food habits of wolverineGulo guloin montane ecosystems of British Columbia, Canada." Wildlife Biology 13, sp2 (October 2007): 31–37. http://dx.doi.org/10.2981/0909-6396(2007)13[31:fhowgg]2.0.co;2.

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White, Joseph D., Steven W. Running, Ramakrishna Nemani, Robert E. Keane, and Kevin C. Ryan. "Measurement and remote sensing of LAI in Rocky Mountain montane ecosystems." Canadian Journal of Forest Research 27, no. 11 (November 1, 1997): 1714–27. http://dx.doi.org/10.1139/x97-142.

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Dhakal, Balram, Michelle A. Pinard, I. A. U. Nimal Gunatilleke, C. V. Savitri Gunatilleke, H. M. S. P. Madawala Weerasinghe, A. L. S. Dharmaparakrama, and David F. R. P. Burslem. "Impacts of cardamom cultivation on montane forest ecosystems in Sri Lanka." Forest Ecology and Management 274 (June 2012): 151–60. http://dx.doi.org/10.1016/j.foreco.2012.02.021.

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Debinski, D. "Montane Meadows as a Microcosm for Predicting Global Change." UW National Parks Service Research Station Annual Reports 29 (January 1, 2005): 70–73. http://dx.doi.org/10.13001/uwnpsrc.2005.3615.

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The last decade has witnessed intensifying, abrupt global climate change. Despite this impact, we know little about when, what, and how changes occur. Most climate research is limited to studies of the abiotic environment, focusing on atmospheric composition and carbon fluxes. These studies fail to provide adequate indicators of climate changes and their impact on habitats and species. Recent and intensifying ecological changes have generated interest in (Root et al. 2003, Thomas et al. 2004), and the need for tools that can help to prepare for global climate shifts. Changes in ecological (biotic) communities are excellent indicators of climate shifts, providing models to predict changes over time. Montane meadows, defined here as persistently nonÂforested habitats in mountain ecosystems, make up a small percentage of terrestrial habitats, but they are likely to exhibit changes much more rapidly than most other areas. These meadows are arrayed along a hydrological gradient (from hydric to mesic to xeric) and inhabited by short-lived plants and highly mobile animal species that can exhibit quick changes in distribution patterns relative to environmental changes. Thus, they can provide an early warning system for other ecosystems across the globe. Currently, the extent and range of climatic changes that will occur in montane meadows are unknown.

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Vallicrosa, Helena, Jordi Sardans, Romà Ogaya, Pere Roc Fernández, and Josep Peñuelas. "Short-Term N-Fertilization Differently Affects the Leaf and Leaf Litter Chemistry of the Dominant Species in a Mediterranean Forest under Drought Conditions." Forests 12, no. 5 (May 12, 2021): 605. http://dx.doi.org/10.3390/f12050605.

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Nitrogen (N) deposition is a key driver of global change with significant effects on carbon (C) cycling, species fitness, and diversity; however, its effects on Mediterranean ecosystems are unclear. Here, we simulated N deposition in an N-fertilization experiment with 15N-labeled fertilizer in a montane evergreen Mediterranean holm oak forest, in central Catalonia, to quantify short-term impacts on leaf, leaf litter elemental composition, and resorption efficiency in three dominant species (Quercus ilex, Phillyrea latifolia, and Arbutus unedo). We found that even under drought conditions, 15N isotope analysis of leaf and leaf litter showed a rapid uptake of the added N, suggesting an N deficient ecosystem. Species responses to N fertilization varied, where A. unedo was unaffected and the responses in P. latifolia and Q. ilex were similar, albeit with contrasting magnitude. P. latifolia benefited the most from N fertilization under drought conditions of the experimental year. These differences in species response could indicate impacts on species fitness, competition, and abundance under increased N loads in Mediterranean forest ecosystems. Further research is needed to disentangle interactions between long-term N deposition and the drought predicted under future climate scenarios in Mediterranean ecosystems.

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Soley-Guardia, Mariano, Ana Carolina Carnaval, and Robert P. Anderson. "Sufficient versus optimal climatic stability during the Late Quaternary: using environmental quality to guide phylogeographic inferences in a Neotropical montane system." Journal of Mammalogy 100, no. 6 (November 27, 2019): 1783–807. http://dx.doi.org/10.1093/jmammal/gyz162.

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Abstract Quaternary climatic oscillations affected species distributions worldwide, creating cycles of connectivity and isolation that impacted population demography and promoted lineage divergence. These effects have been well studied in temperate regions. Taxa inhabiting mesic montane habitats in tropical ecosystems show high levels of endemism and diversification in the distinct mountain ranges they inhabit; such a pattern has commonly been ascribed to past climatic oscillations, but few phylogeographic studies have tested this hypothesis. Here, we combine ecological niche models of species distributions with molecular data to study phylogeographic patterns in two rodents endemic to the highlands of Costa Rica and western Panama (Reithrodontomys creper and Nephelomys devius). In so doing, we apply a novel approach that incorporates a basic ecological principle: the expected positive relationship between environmental suitability and population abundance. Specifically, we use niche models to predict potential patterns of population connectivity and stability of different suitability levels during climatic extremes of the last glacial–interglacial cycle; we then test these predictions with population genetic analyses of a mitochondrial and a nuclear marker. The detailed predictions arising from the different levels of suitability were moderately to highly congruent with the molecular data depending on the species. Overall, results suggest that in these tropical montane ecosystems, cycles of population connectivity and isolation followed a pattern opposite to that typically described for temperate or lowland tropical ecosystems: namely, higher connectivity during the colder glacials, with isolation in montane refugia during the interglacials, including today. Nevertheless, the individualistic patterns for each species indicate a potentially wide gamut of phylogeographic histories reflecting particularities of their niches. Taken together, this study illustrates how phylogeographic inferences may benefit from niche model outputs that provide more detailed predictions of connectivity and finer characterizations of potential refugia through time.

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Golic, Igor. "Structural and productivity characteristics of montane beech forests in the area of Radava mountain." Bulletin of the Faculty of Forestry, no. 111 (2015): 37–44. http://dx.doi.org/10.2298/gsf1511037g.

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This paper presents a typological study of the ecological unit of mountain beech forests in the area of Radava mountain. The aim of this research is to present the basic characteristics of these forests ecosystems through the process of defining forest types. The results will help in defining the forest type and according to the results of this research will create conditions for a more realistic definition of goals in planning the management of these and other forest ecosystems.

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Gharun, Mana, Lukas Hörtnagl, Eugénie Paul-Limoges, Shiva Ghiasi, Iris Feigenwinter, Susanne Burri, Kristiina Marquardt, et al. "Physiological response of Swiss ecosystems to 2018 drought across plant types and elevation." Philosophical Transactions of the Royal Society B: Biological Sciences 375, no. 1810 (September 7, 2020): 20190521. http://dx.doi.org/10.1098/rstb.2019.0521.

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Using five eddy covariance flux sites (two forests and three grasslands), we investigated ecosystem physiological responses to the 2018 drought across elevational gradients in Switzerland. Flux measurements showed that at lower elevation sites (below 1000 m.a.s.l.; grassland and mixed forest) annual ecosystem productivity (GPP) declined by approximately 20% compared to the previous 2 years (2016 and 2017), which led to a reduced annual net ecosystem productivity (NEP). At the high elevation sites, however, GPP increased by approximately 14% and as a result NEP increased in the alpine and montane grasslands, but not in the subalpine coniferous forest. There, increased ecosystem respiration led to a reduced annual NEP, despite increased GPP and lengthening of the growing period. Among all ecosystems, the coniferous forest showed the most pronounced negative stomatal response to atmospheric dryness (i.e. vapour pressure deficit, VPD) that resulted in a decline in surface conductance and an increased water-use efficiency during drought. While increased temperature enhanced the water-use efficiency of both forests, de-coupling of GPP from evapotranspiration at the low-elevation grassland site negatively affected water-use efficiency due to non-stomatal reductions in photosynthesis. Our results show that hot droughts (such as in 2018) lead to different responses across plants types, and thus ecosystems. Particularly grasslands at lower elevations are the most vulnerable ecosystems to negative impacts of future drought in Switzerland. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.

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Grau, Hector Ricardo, Tomas Alfredo Easdale, and Leonardo Paolini. "Subtropical dendroecology—dating disturbances and forest dynamics in northwestern Argentina montane ecosystems." Forest Ecology and Management 177, no. 1-3 (April 2003): 131–43. http://dx.doi.org/10.1016/s0378-1127(02)00316-x.

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Sukumar, R., H. S. Suresh, and R. Ramesh. "Climate Change and Its Impact on Tropical Montane Ecosystems in Southern India." Journal of Biogeography 22, no. 2/3 (March 1995): 533. http://dx.doi.org/10.2307/2845951.

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González-Zamora, Alfredo, Manuel Esperón-Rodríguez, and Víctor L. Barradas. "Mountain cloud forest and grown-shade coffee plantations: A comparison of tree biodiversity in central Veracruz, Mexico." Forest Systems 25, no. 1 (April 1, 2016): 055. http://dx.doi.org/10.5424/fs/2016251-07538.

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Aim of the study: The objective of this work is to compare tree diversity and richness among one grown-shade coffee plantation (CAE) and two sites of montane cloud forests, one preserved (MCF1) and other perturbed (MCF2). We also develop an analysis of the importance of coffee plantations as a refuge of tree species, holding a potential role for conservation.Area of study: Our study area is the coffee region of Coatepec-Xico, in the state of Veracruz, Mexico.Material and methods: We compiled a list of all tree species in each site to determine tree diversity and floristic similarity (dissimilarity). We used different similarity indices and a cluster analysis to show relations among sites.Main results: 2721 individuals from 154 species were registered in the montane cloud forests as a whole. In the grown-shade coffee plantation we registered 2947 individuals from 64 species. The most similar sites were the perturbed montane cloud forest and the grown-shade coffee plantation and the least similar were the preserved montane cloud forest and the grown-shade coffee plantation. The high biodiversity found in all sites and the differences in tree composition between the two montane cloud forests supports evidence of the ecosystems richness in the region.Research highlight: Diversity differences among sites determine that the grown-shade coffee plantation is not substitute for montane cloud forest. CAE’s are developed under similar environmental conditions than the MCF; therefore, coexistence and recombination (replacement) of species make them particularly complementary. CAE’s in Veracruz have a potential role as refuge for biodiversity.

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Curovic, M., Danijela Stesevic, M. Medarevic, R. Cvjeticanin, D. Pantic, and V. Spalevic. "Ecological and structural characteristics of monodominant montane beech forests in the National park Biogradska Gora, Montenegro." Archives of Biological Sciences 63, no. 2 (2011): 429–40. http://dx.doi.org/10.2298/abs1102429c.

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Due to their extraordinary diversity and high level of conservation, the forest ecosystems of Biogradska Gora undoubtedly fall under the most significant forest objects. Owing to the lack of anthropogenic impacts, it is an especially interesting and gratifying research subject for different experts and scientists. In order to implement a sufficiently high biodiversity level management, it is necessary to know the structural characteristics of untouched forests. In this paper we focused our attention on monodominant montane beech forests with their ecological and structural characteristics, as a bioecological basis for environmentally friendly planning and sustainable management of these and similar forest ecosystems.

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Baumgartner, Simon, Marijn Bauters, Matti Barthel, Travis W. Drake, Landry C. Ntaboba, Basile M. Bazirake, Johan Six, Pascal Boeckx, and Kristof Van Oost. "Stable isotope signatures of soil nitrogen on an environmental–geomorphic gradient within the Congo Basin." SOIL 7, no. 1 (March 30, 2021): 83–94. http://dx.doi.org/10.5194/soil-7-83-2021.

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Abstract. Nitrogen (N) availability can be highly variable in tropical forests on regional and local scales. While environmental gradients influence N cycling on a regional scale, topography is known to affect N availability on a local scale. We compared natural abundance of 15N isotopes of soil profiles in tropical lowland forest, tropical montane forest, and subtropical Miombo woodland within the Congo Basin as a proxy to assess ecosystem-level differences in N cycling. Soil δ15N profiles indicated that N cycling in the montane forest is relatively more closed and dominated by organic N turnover, whereas the lowland forest and Miombo woodland experienced a more open N cycle dominated by inorganic N. Furthermore, we examined the effect of slope gradient on soil δ15N within forest types to quantify local differences induced by topography. Our results show that slope gradient only affects the soil δ15N in the Miombo forest, which is prone to erosion due to a lower vegetation cover and intense rainfall at the onset of the wet season. Lowland forest, on the other hand, with a flat topography and protective vegetation cover, showed no influence of topography on soil δ15N in our study site. Despite the steep topography, slope angles do not affect soil δ15N in the montane forest, although stable isotope signatures exhibited higher variability within this ecosystem. A pan-tropical analysis of soil δ15N values (i.e., from our study and literature) reveals that soil δ15N in tropical forests is best explained by factors controlling erosion, namely mean annual precipitation, leaf area index, and slope gradient. Erosive forces vary immensely between different tropical forest ecosystems, and our results highlight the need for more spatial coverage of N cycling studies in tropical forests, to further elucidate the local impact of topography on N cycling in this biome.

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Yepes, Adriana, Andrés Sierra, Luz Milena Niño, Manuel López, César Garay, Diana Vargas, Edersson Cabrera, and Adriana Barbosa. "Biomass and total carbon in oak forests of Southern Colombian Andes: contributions to the REDD+ project-wide approach." Revista de Biología Tropical 64, no. 1 (June 28, 2016): 399. http://dx.doi.org/10.15517/rbt.v64i1.18221.

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Carbon estimations in tropical forests are very important to understand the role of these ecosystems in the carbon cycle, and to support decisions and the formulation of mitigation and adaptive strategies to reduce the greenhouse emission gases (GHG). Nevertheless, detailed ground-based quantifications of total carbon stocks in tropical montane forests are limited, despite their high value in science and ecosystem management (e.g. REDD+). The objective was to identify the role of these ecosystems as carbon stocks, to evaluate the contribution of the pools analyzed (aboveground biomass, belowground biomass and necromass), and to make contributions to the REDD+ approach from the project scale. For this study, we established 44 plots in a heterogeneous landscape composed by old-grown forests located in the Southern Colombian Andes. In each plot, all trees, palms and ferns with diameter (D) ≥ 15 cm were measured. In the case of palms, the height was measured for 40 % of the individuals, following the Colombia National Protocol to estimate biomass and carbon in natural forests. National allometric equations were used to estimate aboveground biomass, and a global equation proposed by IPCC was used for belowground biomass estimation; besides, palms’ aboveground biomass was estimated using a local model. The necromass was estimated for dead standing trees and the gross debris. In the latter case, the length and diameters of the extremes in the pieces were measured. Samples for wood density estimations were collected in the field and analyzed in the laboratory. The mean total carbon stock was estimated as 545.9 ± 84.1 Mg/ha (± S.E.). The aboveground biomass contributed with 72.5 %, the belowground biomass with 13.6 %, and the necromass with 13.9 %. The main conclusion is that montane tropical forests store a huge amount of carbon, similar to low land tropical forests. In addition, the study found that the inclusion of other pools could contribute with more than 20 % to total carbon storage, indicating that estimates that only include the aboveground biomass, largely underestimate carbon stocks in tropical forest ecosystems. These results support the importance of including other carbon pools in REDD+ initiatives’ estimations.

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Futter, M. N., R. C. Helliwell, M. Hutchins, and J. Aherne. "Modelling the effects of changing climate and nitrogen deposition on nitrate dynamics in a Scottish mountain catchment." Hydrology Research 40, no. 2-3 (April 1, 2009): 153–66. http://dx.doi.org/10.2166/nh.2009.073.

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The effect of changing climate and N deposition on montane ecosystems is a topic of considerable importance. Mountains are vulnerable environments and their ecosystems are often in a delicate balance. An application of the INCA-N model is presented to simulate current-day nitrate dynamics in a Scottish mountain lake and to project the possible future effects of climate change and reductions in N deposition on lake nitrate concentration ([NO3−]). The INCA-N model is calibrated using data from 1996–2006 in an attempt to determine the controls on [NO3−] in Lochnagar and process sensitivities to changing climate. Predictions were sensitive to hydrologic, vegetation-related and in-soil processes. Over the longer term, surface water [NO3−] in this mountain ecosystem is expected to increase. From 2020 to 2100, when N deposition is modelled at a constant rate, warmer temperature exerts a stronger effect on N losses to the lake surface than the N deposition. While the effects of a warming climate are projected to lead to increased surface water [NO3−], concentrations are not projected to either return to, or exceed, historical levels.

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Nottingham, A. T., B. L. Turner, J. Whitaker, N. J. Ostle, N. P. McNamara, R. D. Bardgett, N. Salinas, and P. Meir. "Soil microbial nutrient constraints along a tropical forest elevation gradient: a belowground test of a biogeochemical paradigm." Biogeosciences 12, no. 20 (October 26, 2015): 6071–83. http://dx.doi.org/10.5194/bg-12-6071-2015.

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Abstract. Aboveground primary productivity is widely considered to be limited by phosphorus (P) availability in lowland tropical forests and by nitrogen (N) availability in montane tropical forests. However, the extent to which this paradigm applies to belowground processes remains unresolved. We measured indices of soil microbial nutrient status in lowland, sub-montane and montane tropical forests along a natural gradient spanning 3400 m in elevation in the Peruvian Andes. With increasing elevation there were marked increases in soil concentrations of total N, total P, and readily exchangeable P, but a decrease in N mineralization determined by in situ resin bags. Microbial carbon (C) and N increased with increasing elevation, but microbial C : N : P ratios were relatively constant, suggesting homeostasis. The activity of hydrolytic enzymes, which are rich in N, decreased with increasing elevation, while the ratio of enzymes involved in the acquisition of N and P increased with increasing elevation, further indicating an increase in the relative demand for N compared to P with increasing elevation. We conclude that soil microorganisms shift investment in nutrient acquisition from P to N between lowland and montane tropical forests, suggesting that different nutrients regulate soil microbial metabolism and the soil carbon balance in these ecosystems.

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Nottingham, A. T., B. L. Turner, J. Whitaker, N. Ostle, N. P. McNamara, R. D. Bardgett, N. Salinas, and P. Meir. "Soil microbial nutrient constraints along a tropical forest elevation gradient: a belowground test of a biogeochemical paradigm." Biogeosciences Discussions 12, no. 8 (April 30, 2015): 6489–523. http://dx.doi.org/10.5194/bgd-12-6489-2015.

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Abstract. Aboveground primary productivity is widely considered to be limited by phosphorus (P) availability in lowland tropical forests and by nitrogen (N) availability in montane tropical forests. However, the extent to which this paradigm applies to belowground processes remains unresolved. We measured indices of soil microbial nutrient status in lowland, sub-montane and montane tropical forests along a natural gradient spanning 3400 m in elevation in the Peruvian Andes. With increasing elevation there were marked increases in soil concentrations of total N, total P, and readily-extractable P, but a decrease in N mineralization determined by in situ resin bags. Microbial carbon (C) and N increased with increasing elevation, but microbial C:N:P ratios were relatively constant, suggesting homeostasis. The activity of hydrolytic enzymes, which are rich in N, decreased with increasing elevation, while the ratios of enzymes involved in the acquisition of N and P increased with increasing elevation, further indicating a shift in the relative demand for N and P by microbial biomass. We conclude that soil microorganisms shift investment in nutrient acquisition from P to N between lowland and montane tropical forests, suggesting that different nutrients regulate soil microbial metabolism and the soil carbon balance in these ecosystems.

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Peters, Vernon S., and Darcy R. Visscher. "Seed Availability Does Not Ensure Regeneration in Northern Ecosystems of the Endangered Limber Pine." Forests 10, no. 2 (February 10, 2019): 146. http://dx.doi.org/10.3390/f10020146.

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Research Highlights: When biotic interactions such as disease alter both the seed production capacity of stands, and seedling survivorship, the relative importance of seed availability versus substrate specificity may alter future regeneration opportunities for plant populations. Background and Objectives: We investigated the importance of disease severity, seed availability, and substrate limitation to the regeneration dynamics of the endangered limber pine, Pinus flexilis, in two ecosystems with varying forest composition, and different histories of white pine blister rust infection (WPBR; Cronartium ribicola). Materials and Methods: A total of 17 stands from the montane ecoregion (Alberta, Canada) were sampled for seed production between 2007–2010, seedling density, and age structure. Model selection using an information theoretic approach compared a series of a priori models and their combinations, based on our hypotheses on the role biotic variables play in the regeneration process. Results: Despite higher rates of WPBR infection, 2.3 times more seed was available for avian dispersers in the southern ecosystem. Recent seedling regeneration did not correspond to seed production (83 versus 251 seedlings/ha, in southern versus northern ecosystems, respectively), resulting in a seven-fold difference in seed to seedling ratios between ecosystems. Models suggest that disease and vegetation cover were important factors explaining the absence of regeneration in 79.4% of the plots sampled, while basal area (BA) of live limber pine, rocky substrates, ecosystem, South aspects, and slope enhanced limber pine regeneration. Seedling age structures suggest that recent regeneration is less likely in more diseased landscapes, than it was historically (40% versus 72.8% of seedlings < 20 years old, respectively, in southern versus northern ecosystems). Conclusions: At the northern limits of limber pine’s range, seed availability does not ensure regeneration, suggesting that other environmental or biotic factors hinder regeneration. Regeneration was consistently predicted to be lower in the southern ecosystem than in the northern ecosystem, suggesting that natural regeneration and the potential for population recovery are ecosystem dependent. We recommend that monitoring recent seedlings will aid the identification of biotic and abiotic factors affecting regeneration.

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Molina, A., V. Vanacker, E. Brisson, D. Mora, and V. Balthazar. "Long-term effects of climate and land cover change on freshwater provision in the tropical Andes." Hydrology and Earth System Sciences Discussions 12, no. 6 (June 5, 2015): 5219–50. http://dx.doi.org/10.5194/hessd-12-5219-2015.

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Abstract. Andean headwater catchments play a pivotal role to supply fresh water for downstream water users. However, few long-term studies exist on the relative importance of climate change and direct anthropogenic perturbations on flow regimes. In this paper, we assess multi-decadal change in freshwater provision based on long time series (1974–2008) of hydrometeorological data and land cover reconstructions for a 282 km2 catchment located in the tropical Andes. Three main land cover change trajectories can be distinguished: (1) rapid decline of native vegetation in montane forest and páramo ecosystems in ~1/5 or 20% of the catchment area, (2) expansion of agricultural land by 14% of the catchment area, (3) afforestation of 12% of native páramo grasslands with exotic tree species in recent years. Given the strong temporal variability of precipitation and streamflow data related to El Niño–Southern Oscillation, we use empirical mode decomposition techniques to detrend the time series. The long-term increasing trend in rainfall is remarkably different from the observed changes in streamflow that exhibit a decreasing trend. Hence, observed changes in streamflow are not the result of long-term climate change but very likely result from direct anthropogenic disturbances after land cover change. Partial water budgets for montane cloud forest and páramo ecosystems suggest that the strongest changes in evaporative water losses are observed in páramo ecosystems, where progressive colonization and afforestation of high alpine grasslands leads to a strong increase in transpiration losses.

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Martínez, C., C. Jaramillo, A. Correa-Metrío, W. Crepet, J. E. Moreno, A. Aliaga, F. Moreno, M. Ibañez-Mejia, and M. B. Bush. "Neogene precipitation, vegetation, and elevation history of the Central Andean Plateau." Science Advances 6, no. 35 (August 2020): eaaz4724. http://dx.doi.org/10.1126/sciadv.aaz4724.

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Andean uplift played a fundamental role in shaping South American climate and species distribution, but the relationship between the rise of the Andes, plant composition, and local climatic evolution is poorly known. We investigated the fossil record (pollen, leaves, and wood) from the Neogene of the Central Andean Plateau and documented the earliest evidence of a puna-like ecosystem in the Pliocene and a montane ecosystem without modern analogs in the Miocene. In contrast to regional climate model simulations, our climate inferences based on fossil data suggest wetter than modern precipitation conditions during the Pliocene, when the area was near modern elevations, and even wetter conditions during the Miocene, when the cordillera was around ~1700 meters above sea level. Our empirical data highlight the importance of the plant fossil record in studying past, present, and future climates and underscore the dynamic nature of high elevation ecosystems.

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Rowe, Julia A., Creighton M. Litton, Christopher A. Lepczyk, and Brian N. Popp. "Impacts of Endangered Seabirds on Nutrient Cycling in Montane Forest Ecosystems of Hawai‘i." Pacific Science 71, no. 4 (October 2017): 495–509. http://dx.doi.org/10.2984/71.4.7.

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Gómez‐Aparicio, Lorena, Jose M. Gómez, Regino Zamora, and Janis L. Boettinger. "Canopy vs. soil effects of shrubs facilitating tree seedlings in Mediterranean montane ecosystems." Journal of Vegetation Science 16, no. 2 (February 24, 2005): 191–98. http://dx.doi.org/10.1111/j.1654-1103.2005.tb02355.x.

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ALI, A., L. BADSHAH, and F. HUSSAIN. "VEGETATION STRUCTURE AND THREATS TO MONTANE TEMPERATE ECOSYSTEMS IN HINDUKUSH RANGE, SWAT, PAKISTAN." Applied Ecology and Environmental Research 16, no. 4 (2018): 4789–811. http://dx.doi.org/10.15666/aeer/1604_47894811.

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Journal articles on the topic 'Montane Ecosystems'

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