Subalpine Shrubland Research Articles

Seasonal variation in the food composition of the Bolkar Mountain Viper, Montivipera bulgardaghica (Nilson & Andren, 1985), in the Central Taurus Mountains, Anatolia

The Bolkar Mountain Viper, Montivipera bulgardaghica (Nilson & Andren, 1985), is a mountain viper found in the eastern Mediterranean region. In this study, we present data on the seasonal variation in diet composition across two different habitats in the Central Taurus Mountains of Anatolia, Türkiye. The Karboğazı population inhabits a subalpine shrubland, while the Göller Yaylası population resides in forested land. The vipers primarily consumed Lacertidae (47%), followed by Orthoptera (27%), Chilopoda (18%), and Scincidae (8%) in number. In spring, the diet of the Karboğazı population was mainly composed of Lacertidae but shifts toward Orthoptera during summer and autumn. In contrast, the Göller Yaylası population fed on Lacertidae throughout the entire active season. Overall, the Karboğazı population primarily consumed invertebrates, whereas the Göller Yaylası population predominantly fed on lizards. Both populations exhibited partial niche overlap. There was no significant difference in diet composition between sexes, but prey type and quantity varied with the season. Prey diversity increased in summer and decreased in autumn and spring, corresponding with the prey availability in the environment.

Mesoscale soil moisture measurements along the rover route using the mobile cosmic-ray neutron sensing in the eastern Tibetan Plateau

Water resources in the soil play an essential role in hydrological processes and ecosystem functions on the Tibetan Plateau. However, accurately measuring soil moisture distribution in this region presents challenges due to the diverse ecosystem types, complex terrain, and harsh environmental conditions. In this study, we introduce an approach for estimating mesoscale soil moisture in the Qilian Mountains (QLM) region of the eastern Tibetan Plateau using a cosmic-ray neutron rover. Soil moisture estimates derived from neutron count rates, newly adjusted by vegetation effects, demonstrated good agreement with soil moisture measurements obtained through soil sampling at 26 calibration sites across the region (RMSE = 0.025 g g−1). The calibration parameter N0_NDVI was 443 cpm in the QLM. Utilizing NDVI as vegetation correction method showed potential improvements in the accuracy of converting neutron counts to soil moisture across the diverse mountainous ecosystem types. The newly developed calibration equation provided a high-precision, high spatial resolution soil moisture transect across various landscapes measured by the rover. The average mesoscale soil moisture along the rover route varied by ecosystem types, with values of 0.10 g/g in deserts, 0.17 g/g in grasslands, 0.13 g/g in forests, 0.18 g/g in subalpine shrublands, and 0.20 g/g in croplands. Land cover types emerged as crucial determinants of mesoscale soil moisture variability in the QLM region. These findings offer valuable mesoscale soil moisture data and new insights into soil water information at the transect scale across diverse ecosystem types in the Tibetan Plateau.

Hawaiian Treeline Ecotones: Implications for Plant Community Conservation under Climate Change.

Species within tropical alpine treeline ecotones are predicted to be especially sensitive to climate variability because this zone represents tree species' altitudinal limits. Hawaiian volcanoes have distinct treeline ecotones driven by trade wind inversions. The local climate is changing, but little is known about how this influences treeline vegetation. To predict future impacts of climate variability on treelines, we must define the range of variation in treeline ecotone characteristics. Previous studies highlighted an abrupt transition between subalpine grasslands and wet forest on windward Haleakalā, but this site does not represent the diversity of treeline ecotones among volcanoes, lava substrates, and local climatic conditions. To capture this diversity, we used data from 225 plots spanning treelines (1500-2500 m) on Haleakalā and Mauna Loa to characterize ecotonal plant communities. Treeline indicator species differ by moisture and temperature, with common native species important for wet forest, subalpine woodland, and subalpine shrubland. The frequency or abundance of community indicator species may be better predictors of shifting local climates than the presence or absence of tree life forms per se. This study further supports the hypothesis that changes in available moisture, rather than temperature, will dictate the future trajectory of Hawaiian treeline ecotone communities.

Seed germination of five species from the subalpine shrubland of a mountainous oceanic island with high conservation value (Reunion Island)

Little is known about the seed ecology of native plants from subalpine and alpine vegetation zones on oceanic islands, although their biodiversity is unique and vulnerable (e.g. facing fires and biological invasions). This study of seed germination focuses on five species, which are representative of the subalpine shrubland of Reunion Island. The main objectives are to identify the presence of dormancy and light requirements, and to evaluate whether GA3 or a smoke-infused water could substitute for the light requirement for seed germination. Over one month, germination tests were performed under different conditions at three temperatures (15, 20 and 25 °C), in light (12-hours light/12-hours dark) and in dark. Seeds were also treated using a single spraying of gibberellic acid (GA3 at 1000 ppm) and a smoke-infused water (named Smoke Water in the study). No dormancy was detected for Stoebe passerinoides. For Erica reunionensis, Agarista buxifolia, Hubertia tomentosa and Hypericum lanceolatum subsp. angustifolium, a potential non-deep physiological dormancy (with a conditional dormancy state) was detected. Moreover, for Agarista buxifolia and Erica reunionensis (Ericaceae), light is required for seed germination. Gibberellic acid (GA3 at 1000 ppm) substitutes for light, except at 25 °C for E. reunionensis. Smoke Water does not improve seed germination, except at 15 °C in dark for E. reunionensis. A better understanding of seed germination for species from subalpine and alpine vegetation zones will mean better threat management and restoration actions.

Biochemical composition and function of subalpine shrubland and meadow soil microbiomes in the Qilian Mountains, Qinghai-Tibetan plateau, China.

Microorganisms participate in the soil biogeochemical cycle. Therefore, investigating variations in microbial biomass, composition, and functions can provide a reference for improving soil ecological quality due to the sensitivity of microorganisms to vegetation coverage changes. However, the differences in soil microorganisms between shrubland and meadow have not been investigated in ecologically vulnerable subalpine areas. This study aimed to investigate the biochemical composition and functions of the soil microbial community under two shrublands and a meadow at high altitudes (3,400–3,550 m). Three sites under two shrublands, Rhododendron thymifolium (RHO) and Potentilla fruticosa (POT), and one meadow dominated by Kobresia myosuroides (MEA), were selected on the southern slope of the Qilian Mountains on the northeastern edge of the Qinghai–Tibetan Plateau, China. Soil physicochemical properties, the microbial community composition expressed by the phospholipid fatty acid (PLFA) biomarker, and enzyme activities were analyzed as well as their relationships. The results showed that water holding capacity and the soil carbon, nitrogen, and potassium content in RHO and POT were higher than those in the MEA. Moreover, the soil active carbon, dissolved organic carbon, total nitrogen, and dissolved total nitrogen content in RHO were higher than those in POT. The abundance of total PLFAs, bacteria, and fungi beneath the shrublands was considerably higher than that in the MEA. The PLFA abundance in RHO was significantly higher than that in POT. The fungal-to-bacterial ratio of RHO and POT was significantly higher than that in the MEA. The activities of β-glucosidase, cellobiohydrolase, and leucine aminopeptidase were the highest in RHO among the three vegetation types, followed by POT and MEA. The redundancy analysis indicated that the biochemical composition of the soil microorganisms and enzyme activities were driven by total nitrogen, dissolved organic carbon, water holding capacity, and soil organic carbon. Therefore, shrublands, which have higher biomass, can improve soil moisture status, increase soil carbon and nitrogen content (especially active carbon and active nitrogen), and further increase the abundance of total PLFAs, bacteria, and fungi. The increase of microbial biomass indirectly enhances the activity of relevant soil enzymes. The variations in PLFA abundance and enzyme activities can be attributed to shrub species, especially evergreen shrubs, which create more favorable conditions for soil microorganisms. This study provides a theoretical basis for investigating the soil biogeochemical cycle and a scientific basis for soil management and vegetation restoration in the subalpine regions.

Salix shrub encroachment along a 1000 m elevation gradient triggers a major ecosystem change in the European Alps

Shrub encroachment, a globally recognized response to climate warming, usually involves late successional species in mountain environments, without alteration to climax communities. We show that a major ecosystem change is occurring in the European Alps across a 1000 m elevation gradient, with pioneer hygrophilous Salix shrubs, previously typical of riparian forests, wetlands and avalanche ravines, encroaching into the climax communities of subalpine and alpine belts shrublands and grasslands, as well as snowbeds, pioneer vegetation and barren grounds in the nival belt.We analyzed Salix recruitment through dendrochronological methods, and assessed its relationships with climate and atmospheric CO2 concentration. The dendrochronological data indicated that Salix encroachment commenced in the 1950s (based on the age of the oldest Salix individuals, recruited in 1957), and that it was correlated with increasing atmospheric CO2 concentration, spring warming and snow cover decrease. Hygrophilous Salix shrubs are expanding their distribution both through range filling and upwards migration, likely achieving competitive replacement of species of subalpine and alpine climax communities. They benefit from climate warming and CO2 fertilization and are not sensitive to spring frost damage and soil limitations, being observed across a gradient of soil conditions from loose glacial sediments in recently deglaciated areas (where soils had not had sufficient time to develop) to mature soils such as podzols (when colonizing late successional subalpine shrublands).Salix encroachment may trigger ecosystem and landscape transformations, promoting the development of forests that replace pre‐existing subalpine shrublands, and of open woodlands invading alpine grasslands and snowbeds, making the alpine environment similar to sub‐Arctic and Arctic areas. This results in a new threat to the conservation of the plant species, communities and landscapes typical of the alpine biota, as mountain ranges such as the Alps provide limited opportunities for upward migration and range‐shift.

Temperate Eurasian Origins of Hawaiian Chenopodium (Amaranthaceae), Plus Description of a New Subspecies Endemic to Moloka‘i

Abstract—Hawaiian taxa of Chenopodium are tetraploids and are distinguished from other members of the circumglobally distributed genus by minute morphological characters. Because of these reasons, the geographic origin of Hawaiian Chenopodium has remained unclear. Across the Hawaiian Archipelago, taxa of Chenopodium are morphologically variable and grow in highly disparate xeric habitats, especially in terms of precipitation, temperature, wind, salt spray, and solar irradiation. Habitats include dry subalpine shrublands, sandy beach strands on atolls in the Northwest Hawaiian Islands, dry to mesic forests, and precipitously tall sea cliffs of northwestern Moloka‘i. From the Moloka‘i sea cliffs, which are battered by high energy winds, salt spray, and strong seasonal precipitation, we describe C. oahuense subspecies ilioensis as segregated from the widespread Hawaiian C. oahuense sensu lato. Morphometric analyses distinguish C. oahuense subsp. ilioensis by its strongly prostrate to scandent habit, thick succulent leaves, smaller average leaf size, limited lobing of the laminar margins, and smaller seeds. Phylogenetic analyses using two DNA regions (the plastid gene rpl32-trnL and nuclear ITS) of newly sequenced individuals of C. oahuense s. l. and C. oahuense subsp. ilioensis plus outgroup taxa support the monophyly of Hawaiian Chenopodium and reveal a geographic origin of temperate Eurasia. Two equivocal hypothetical scenarios are discussed regarding the likely sequence of events leading to the arrival of Chenopodium in Hawaiian Islands followed by possible in situ speciation of the Moloka‘i endemic C. oahuense subsp. ilioensis.

Contrasting effects of winter and summer climate on Holocene montane vegetation belts evolution in southeastern Qinghai-Tibetan Plateau, China

Montane vegetation belts are sensitive to climate change; however, it is uncertain to what degree their evolution is influenced by changes in mean annual temperature or seasonal climate. In this study, we use pollen assemblages from a high elevation lake (3780 m.a.s.l.) in the Gongga Mountains on the southeast margin of the Qinghai-Tibetan Plateau, China, to study changes in altitudinal vegetation zones during the last 12,000 years. The relationships between vegetation belts and winter and summer climate parameters are analyzed. Results indicate that winter temperature mainly controlled the development of evergreen broadleaved forest (Cyclobalanopsis and Taxodiaceae), deciduous broadleaved forest (Betula), and sub-alpine shrubland (Rosaceae, Cyperaceae and Gramineae dominated). In contrast, the development of temperate coniferous forest (Pinus and Tsuga) and alpine herbfield (Artemisia and Chenopodiaceae) was mainly controlled by summer temperature and precipitation. Results show that winter temperature gradually increased from the Greenlandian to Meghalayan, indicating that the main driving factor was winter solar insolation in the Northern Hemisphere. Meanwhile, changes in summer temperature and precipitation are consistent with the results from Indian monsoon-dominated areas of China, suggesting that the summer climate in this region is mainly driven by the migration of the Intertropical Convergence Zone. Our findings suggest that the influence of seasonal climate changes should be considered on the evolution of montane vegetation belts.

Differences of soil CO2 flux in two contrasting subalpine ecosystems on the eastern edge of the Qinghai-Tibetan Plateau: A four-year study

Alpine and subalpine ecosystems on Qinghai-Tibetan Plateau are rich in soil organic carbon and are among the most sensitive regions to climate change, while little is known about the dynamics of soil carbon dioxide (CO2) in alpine/subalpine ecosystems except for the grassland on the plateau. In this study, the monthly and inter-annual variations in soil CO2 emission from a subalpine coniferous forest and a subalpine shrubland ecosystem on the eastern edge of the Qinghai-Tibetan Plateau were investigated from 2012 to 2015 using the opaque steady-state chamber method. Soil CO2 flux rate during the growing season ranged from 153.3 to 683.6 mg m−2 h−1 in the coniferous forest, being twice of that (76.6–347.3 mg m−2 h−1) in the shrubland, due to the elevation-induced differences in soil temperature and water content and the vegetation-induced differences in soil carbon and nitrogen pools. Both ecosystems showed large monthly variations in soil CO2 flux rate, while relative to the coniferous forest, the shrubland had a less inter-annual variation in soil CO2 emission. The two ecosystems had the same temperature sensitivity of soil CO2 emission, which suggests that they will respond similarly to global warming concerning soil CO2 flux rate. The results highlight the importance of soil CO2 emission in subalpine forest and shrubland ecosystems, which can be helpful to reduce the uncertainty of regional estimates of carbon budget in subalpine regions under global warming.

Evaluating landscape changes using vegetation and land-use maps: an integrated approach

ABSTRACTOver the past 60 years, European mountain landscapes have been affected by land abandonment coupled with urbanisation through tourist exploitation. The Bormio surroundings (southern-central Alps, Italy) are an exemplary case study for these phenomena. To evaluate their landscape changes of the last 50 years, a sequence of two vegetation maps (1959, 1975) and a land-use map (2009) were harmonised in terms of spatial scale and thematic contents. The cartographic units were reclassified as Landscape Elements (LE) on the basis of their dominant species. Change at landscape and LE level were analysed by a set of non-redundant metrics. The loss and fragmentation of meadows, as well as an increasing recovery of woodlands and a doubling of urbanised areas, characterised landscape changes.Meadows and subalpine shrublands were highlighted as being the most threatened landscape elements. The advisability of landscape monitoring for the conservation of the endangered habitats is briefly discussed.

Effects of prescribed burning for pasture reclamation on soil chemical properties in subalpine shrublands of the Central Pyrenees (NE-Spain)

The abandonment of the traditional pastoral activities in the subalpine grasslands of the Central Pyrenees (NE-Spain) has resulted in shrub encroachment processes that are dominated by species such as the Echinospartum horridum. Therefore, prescribed burning has been recently readopted in this region as a management tool to stop the spread of shrubs and recover grasslands. We aimed to assess the effect that this practice may have on soil chemical properties such as SOC, N, pH, EC, water-extractable and exchangeable cations (Ca2+, Mg2+ and K+), cation exchange capacity, inorganic N forms (N-NH4+ and N-NO3−) and available P. We studied two prescribed burnings conducted at the subalpine level of the Central Pyrenees in the municipalities of Tella-Sin (April 2015) and Buisán (November 2015). At each site, the topsoil was sampled in triplicate at soil depths of 0–1, 1–2 and 2–3 cm immediately before (U), immediately after (B0) and one year after (B12) burning, and litter and/or ashes were removed prior to sampling. The results indicate that in the B0 samples, burning significantly reduced the SOC and N contents as well as the exchangeable Ca2+ and Mg2+ at 0–1 cm, whereas the rest of the studied properties remained virtually unchanged. However, in the B12 samples we detected a decrease of nutrient content that was probably related to leaching and/or erosion processes.

Effects of prescribed burning on soil organic C, aggregate stability and water repellency in a subalpine shrubland: Variations among sieve fractions and depths

Soil organic matter, aggregation and water repellency are relevant interrelated soil properties that can be affected by fire. The aim of this work was to analyse the effects of shrub prescribed burning for pasture reclamation on the soil aggregate stability, organic carbon and water repellency of different soil depths and aggregate sizes in a subalpine environment. Soil samples were collected from an area treated by an autumnal low-intensity prescribed fire in the Central Pyrenees (NE-Spain) at 0–1, 1–2, 2–3 and 3–5 cm depths just before and ~1 h, 6 months and 12 months after burning. Samples were separated as whole soil (<10 mm) and 6 sieve fractions, <0.25, 0.25–0.5, 0.5–1, 1–2, 2–4 and 4–10 mm. We analysed soil organic C (SOC), aggregate stability (AS) and soil water repellency (SWR). In the unburned samples, SOC and SWR were higher in the <0.25 to 2 mm sieve fractions than the 2 to 10 mm sieve fractions. Fire severely and significantly decreased the SOC content in the whole soil and the <0.25 mm fraction at 0–1 cm depth and in the 0.25–0.5 mm fraction at 0–2 cm depth. SWR was reduced by burning mainly at 0–1 cm depth for the whole soil and the <0.25 to 2 mm sieve fractions. Nevertheless, the AS of the 0.25–0.5 mm aggregates increased after fire, while the rest of the sieve fractions remained virtually unaffected. One year after the prescribed burning, SOC slightly increased and SWR recovered in the fire-affected fractions, while the AS for all aggregate sizes and depths showed a considerable decrease. The results suggest that the direct effects of burning are still present one year after burning, and the post-fire situation may pose an increased risk of soil loss. Furthermore, our results indicate that fine soil fractions are more likely to be affected by fire than coarser soil fractions and highly influence the whole soil behaviour.

祁连山亚高山灌丛优势植物水分来源

祁连山亚高山灌丛优势植物水分来源

Agrobiodiversity and genetic erosion of crop varieties and plant resources in the Central Great Caucasus

Abstract Kazbegi Municipality is located in the Central Great Caucasus at an altitude between 1250 and 5047 m a.s.l. Agriculture of this area is extreme internal variability and complexity, with a multiplicity of highly localized providing the habitats and agricultural lands for much genetic erosion of crop varieties, animals, plants, fungi, and other life forms for wild plant resources. Historically, Kazbegi producers had begun cultivating the land to prepare for planting in of distribution local varieties of wheat, barley, rye, oats, etc. In the only cereals, legumes, herbs and some fruits are cultivated in alpine zone as the upper limit till the location of 2160 m a.s.l. Genetic erosion has been determined historically of aboriginal crops from sheep and cattle grazing problem and reached extreme levels from 1970s in Kazbegi Municipality and causes a problem to maintain agriculture. Plant resources remained in forests and subalpine grasslands and shrub lands. The problems of these materials are habitat degradation by disturbance in many forest types with destroyed and burned. Tree seedlings are grazing by animals and forest is not restoring naturally. Forest planting is good relation for restoration of plant wild species resources. Investigation on exchange on mountain agriculture and plant resources will now be rapidly accelerated in the vital interests of mountain communities.

Patterns of Floral Visitation to Native Hawaiian Plants in Presence and Absence of Invasive Argentine Ants

Abstract: Invasive ants can influence abundance and diversity of insect pollinators, and this effect may be expected to be especially strong on oceanic islands. We examined abundance of native Hylaeus bees and patterns of flower visitation to three native Hawaiian plant species (Leptecophylla tameiameiae, Santalum haleakalae, and Geranium cuneatum) in presence and absence of invasive Argentine ants (Linepithema humile) in the subalpine shrubland of Haleakalā volcano. Native bees, nonnative honeybees, and microlepidoptera were responsible for the majority of visits to flowers of the three plant species. Ants visited flowers of S. haleakalae and G. cuneatum relatively commonly in ant-invaded zones but were less common or absent on flowers of L. tameiameiae in the same zones. Zones with ants had fewer Hylaeus bees in yellow pan traps than the zone without ants, and overall flower visitation rates to one plant species, G. cuneatum, were six times lower in sites containing ants. In one of two observation years...

Assessing temperature sensitivity of subalpine shrub phenology in semi-arid mountain regions of China

Subalpine shrubs are undergoing, or have experienced profound changes by force of recent climate anomalies, such as the alteration in temporal niche of phenophases and the dynamic interaction with ambient conditions. As cold biomes in high-altitude ecoregions, they have drawn a growing concern of the potential vulnerability to current and future climate change. In this study, we retrieved the time series (2000–2013) of satellite-based phenological transitions (the onset and offset of vegetative growth) for subalpine shrubs at five individual sites in the Qilian Mountains in northwestern China. Our goals were to identify the climatic constraints on the timing of leaf-out and leaf-fall, and to project these phenological patterns under the future climate conditions. To achieve these goals, the relationships between these regional phenological events and climate variables were investigated with univariate and multivariate time series models, and the future phenological dynamics were forecasted for two decades based on the best predictive models under the A2 and B2 of IPCCs Special Report on Emissions Scenarios (SRES). Our results generally revealed site-dependent phenology–climate relationships, which involved an immediate phenological response to the mean or minimum temperature in the corresponding month of occurrence, and a lagged cumulative climate effect across preceding months and seasons. Average temperature during a certain period has been demonstrated as an important limiting factor for plant growth. However, our results also provided evidence for the minimum temperature controls of the development of phenological events in subalpine shrublands, possibly due to a close association with the frequency of frost risk in spring and autumn. Under future climate conditions, an overall lengthening of the active growing season is expected at each of the study sites depending on elevation. Consequently, net carbon uptake by shrubs will benefit from the increased temperature.

Biomass, Productivity, and Nutrient Allocation in Subalpine Shrublands and Meadows of the Emerald Lake Basin, Sequoia National Park, California

The Emerald Lake Basin provides a long-term site for research on hydrology, ecology, and biogeochemistry, as well as baseline data for a representative subalpine watershed in the Sierra Nevada of California. Field studies provided quantitative data on the biomass, net primary production, and nutrient allocation of major subalpine shrub and meadow communities. Measurements carried out over two growing seasons found aboveground biomass per unit canopy area was 3857 g m-2 in Chrysolepis sempervirens, 3360 g m-2 in Salix orestera, and 1614 g m-2 in Phyllodoce breweri. The biomass for Chrysolepis and Salix canopies were high compared to other published data for subalpine and alpine shrublands, but the Phyllodoce biomass was comparable to values for ericaceous heath in the Rocky Mountains and European Alps. Wet and dry meadows had 377 and 98 g m-2, respectively, in aboveground living tissues, comparable to values from the Rocky Mountains and European Alps. Belowground biomass for shrub communities was the highest for Phyllodoce (3670 g m-2), followed by Chrysolepis (2400 g m-2) and Salix (2070 g m-2). The wet meadow community had a surprisingly high belowground biomass of 2897 g m-2, reflecting the dominance of large perennial herb species. This resulted from a root:shoot ratio of 8.21 compared to 5.72 in the dry meadow community. Canopies of Chrysolepis and Salix had root:shoot ratios of 0.62 and 0.61, respectively, and Phyllodoce a ratio of 2.27.

The Sensitivity of the High Mountain Ecosystems of New Guinea to Climatic Change and Anthropogenic Impact

The New Guinea alpine-subalpine zone is the highest, largest, and wettest such region on any tropical island and it preserves great variations in biodiversity between the individual mountain areas. Relatively few plant species are confined to the alpine zone and this may reflect a limited time for adaptation by herbaceous species arriving in the formerly extensive alpine-subalpine biome. In the Pleistocene a zone above 3400 m was affected by glaciation while open subalpine habitat was greatly expanded by cooler climates and low levels of CO2 which hindered the formation of subalpine forest. With post-glacial warming, the subalpine contracted and open areas were invaded by shrublands and forest. Early to late Holocene opening out of the subalpine forest and shrublands is associated with fire that was a result of hunting by humans. This process starts early in some areas but is late or absent on more remote areas. The alpine is threatened by increased warming and potential invasion by emergent shrubs but is likely to prove resilient to extinction provided that wet conditions continue to prevail. Changing cultural use of high altitudes suggests that the subalpine shrublands are recovering in some areas. However, some mammals and bird species seem to have been lost or become restricted on mountains that are accessible from population centers at lower altitude. With few exceptions, management consists of benign neglect although widespread fires in 1997–1998 point to continuing human impacts linked to drought events. The large mine on Mount Jaya influences subalpine usage over a large area. Tourism is very minor and unlikely to expand while political problems affect both Papua New Guinea and Papua province and logistics remain a severe difficulty. However, locally managed tourism on Mount Wilhelm provides a good model for future development.

Water relations and microclimate around the upper limit of a cloud forest in Maui, Hawai'i

The goal of this study was to determine the effects of atmospheric demand on both plant water relations and daily whole-tree water balance across the upper limit of a cloud forest at the mean base height of the trade wind inversion in the tropical trade wind belt. We measured the microclimate and water relations (sap flow, water potential, stomatal conductance, pressure-volume relations) of Metrosideros polymorpha Gaudich. var. polymorpha in three habitats bracketing the cloud forest's upper limit in Hawai'i to understand the role of water relations in determining ecotone position. The subalpine shrubland site, located 100 m above the cloud forest boundary, had the highest vapor pressure deficit, the least amount of rainfall and the highest levels of nighttime transpiration (EN) of all three sites. In the shrubland site, on average, 29% of daily whole-tree transpiration occurred at night, while on the driest day of the study 50% of total daily transpiration occurred at night. While EN occurred in the cloud forest habitat, the proportion of total daily transpiration that occurred at night was much lower (4%). The average leaf water potential (Ψleaf) was above the water potential at the turgor loss point (ΨTLP) on both sides of the ecotone due to strong stomatal regulation. While stomatal closure maintained a high Ψleaf, the minimum leaf water potential (Ψleafmin) was close to ΨTLP, indicating that drier conditions may cause drought stress in these habitats and may be an important driver of current landscape patterns in stand density.

Subalpine Vegetation Change 14 Years after Feral Animal Removal on Windward East Maui, Hawai'i

Abstract: Considerable time and effort has been spent removing nonnative ungulates from sensitive subalpine and forest areas in Hawai'i, with less effort dedicated to documenting changes in plant community structure after feral animal removal. Abundance of native and nonnative vegetation was quantified in a study comparing plots both before (1994) and 14 yr after (2008) removal of feral animals from windward East Maui subalpine and forest habitat in Waikamoi Preserve. An analysis of changes in abundance in two vegetation layers documented increases in relative cover of native subalpine vegetation: bryophytes tripled and lichens increased over nine times in the subalpine shrubland habitat within the ground cover (0 to 1 m) layer, and alien grass cover was halved. In the understory (1 to 2 m) layer, native ferns increased significantly, and native shrub cover tripled. In the forest habitat, bryophytes increased in both layers, and lichens increased in the understory layer. Higher-elevation plots in 2008 mor...