Subalpine Woodland Research Articles

Short-Interval, High-Severity Wildfire Depletes Diversity of Both Extant Vegetation and Soil Seed Banks in Fire-Tolerant Eucalypt Forests

Many plant species are well-adapted to historical fire regimes. An increase in the severity, frequency, and extent of wildfires could compromise the regenerative capacity of species, resulting in permanent shifts in plant diversity. We surveyed extant vegetation and soil seed banks across two forest types with contrasting historical fire regimes—Shrubby Dry Forest (fire return interval: 10–20 years) and Sub-Alpine Woodland (50–100 years). Over the past 20 years, both forests have been subject to repeated, high-severity wildfires at intervals significantly shorter than their historical return intervals. We examined the soil seed bank response to fire-cued germination, and whether the plant diversity in soil seed banks and extant vegetation demonstrated similar responses to short-interval, high-severity wildfires. The soil seed bank demonstrated a positive response to heat in combination with smoke, and for the Sub-Alpine Woodland, this was limited to sites more frequently burnt by fire. With an increase in fire frequency, there was a decline in species richness and Shannon’s Diversity and a shift in species composition in both extant vegetation and the soil seed bank. The fire frequency effects on the relative richness of trait associations were restricted to the Shrubby Dry Forest, and included an increase in short-lived obligate seeders, wind-dispersed species, and ant-dispersed shrubs in burnt relative to long unburnt sites in both extant vegetation and the soil seed bank. Graminoids were the most abundant component of the soil seed banks of Sub-Alpine Woodlands, and this increased with more frequent fire, with a similar trend (p = 0.06) in extant vegetation. Clear shifts in plant diversity in both soil seed banks and extant vegetation in forest types with contrasting historical fire regimes suggest that emerging fire regimes are pushing ecosystems beyond their historical range of variability, including potentially more flammable states and a decline in the buffering capacity of soil seed banks.

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.

Alternating dominant effects of temperature and precipitation along elevational gradient on the alpine and subalpine vegetation activities in southwestern China

Elevation plays a pivotal role in modulating hydroclimatic dynamics, changing vegetation activity and shaping vegetation distribution patterns in alpine regions. Nevertheless, a conspicuous knowledge gap persists regarding the interaction between climate drivers on vegetation activity. In this study, we investigated the spatio-temporal patterns of the Normalized Difference Vegetation Index (NDVI), a proxy for vegetation activity, and examined its interactions with temperature (T) and precipitation (P) along elevational gradient (EG) in the Alpine and Sub-alpine Woodlands of Southwest China (ASWSC) during 2001–2018. We found that approximately 24% vegetation in ASWSC exhibited significant greening trend, as a result of regional warming and slight wetting during the study period. The greening and browning rates were both elevational asymmetric, with higher rates at lower elevations. We also illustrated an alternating domination of T - P on vegetation activity along EG. This suggested a roughly antagonistic effect between the two drivers within the whole vegetation elevation range except for a synergistic effect in the sub-alpine forests zone between 2300 - 4200 m. The antagonistic effect tended to be more pronounced in warm and dry years, while the synergistic effect was more evident in cold and wet years. Specifically for different vegetation types, we found an insignificant T - P interactive effect along EG in indigenous evergreen needleleaf forest (ENF) and evergreen broadleaf forest (EBF), in contrast to the significant synergistic effect in the regenerated deciduous broadleaf forest (DBF) and mixed forest (MF) and antagonistic effect in shrubland and grassland types. In summary, our study revealed alternating-dominant effects of temperature and precipitation on vegetation activity along EG. These findings will deepen our understanding of vegetation resistance and resilience to climate change and eventually contribute to establishing a scientific foundation for effective ecosystem management and conservation practices in alpine region.

Air temperature changes due to altitude above sea level in the Northern Ural Mountains

The research is devoted to an urgent modern problem: the identification of temperature factors that limit the distribution and survival of plants in the mountainous conditions of the Northern Urals. The article’s aim is to determine the air temperature in four altitudinal zones of the southern part of the Northern Urals (Sverdlovsk region 59º30´N, 59º15´E) and to identify regression relationships of the obtained temperature data with control temperature data from the nearest meteorological station. Registration of air temperatures was carried out from May to September 2019 around the clock, every two hours in the mountain forest zone (at an altitude of 460 and 640 m above sea level) under the canopy of Siberian stone pine forests, in the zone of subalpine woodlands with elements of mountain forest tundra (820 m above sea level) and on a plateau in the mountain tundra zone (1030 m above sea level). It has been established that the change in air temperature at different altitude levels and at the nearest meteorological station (far from 60 km, at an altitude of 202 m above sea level) occurs relatively synchronously. Difference between average daily temperatures at altitudes of 460, 640, 820 and 1030 m above sea level and the control data of the meteorological station is 2.2, 3.0, 4.7 and 5.1ºC respectively. For all altitude levels, a reliable close straight-line relationship between average daily air temperatures and meteorological station data has been established. The altitudes of 460, 640, 820 and 1030 m above sea level correspond to the coefficients of determination ( R 2) equal to 0.96, 0.95, 0.92 and 0.88. The relationship of the minimum temperatures of the corresponding altitude levels with the control data is also quite high ( R 2 is not lower than 0.7). With the help of the identified relationships and the obtained regression equations, it is possible to retrospectively restore the dynamics of the thermal regime according to the meteorological station data for mountain habitats of different altitudes in the southern part of the Northern Urals over a long period. Including extreme critical temperatures, which act as factors limiting the resettlement and survival of plants and determine the ecosystem biodiversity.

The impact of climate change and wildfire on decadal alpine vegetation dynamics

Context Climate-induced changes of alpine vegetation diversity, cover and composition have been recorded globally, but most insights have been gleaned from field studies over small spatiotemporal scales. Aims We assess dynamics in climate and vegetation of Australia’s highest and most biologically diverse alpine area that surrounds Mount Kosciuszko (~455 km2), as well as recovery following the 2003 wildfires. Methods Climatic changes were analysed using gridded climate data for mean annual temperature (1910–2019) and seasonal precipitation (1900–2019), and changes in snow cover were assessed from snow course records (1954–2021). A vegetation cover time series (1990, 2000, 2010, 2020) was modelled with an optimised random forest classification using recursive feature selection, and the LandTrendr algorithm was used to detect areas burnt during wildfires. Key results Over time, temperatures and summer precipitation increased, whereas snow cover and winter precipitation decreased. Subsequently, vegetation dynamics were dominated by the densification of subalpine woodlands at lower elevations, replacing dry and wet heathlands. There was treeline stasis but upslope advancement of dry and wet shrublines but grassland vegetation types were relatively stable. However, in burnt areas there was suppressed upslope advancement of shrublines, treeline recession and relatively less expansion of subalpine woodlands. Conclusions Alpine vegetation may be impacted by climate change incrementally through relatively gradual changes in climatic conditions, and transformatively through landscape-level disturbance from wildfires. Implications Higher temperatures and altered precipitation regimes increase the frequency and severity of wildfires, which may be amplified by increasing fuel loads and dryness from the proliferation and advance of woody vegetation in alpine areas.

Fire in Mexican grassy–pine ecosystems

AbstractAimsFire is an important factor contributing to the diversity of many ecosystems. Unfortunately, misconceptions about fire frequently guide policies, threating fire‐prone ecosystems whose persistence depends on such disturbance. In this paper, we highlight the importance of fire, both current and in recent history, in grassy–pine ecosystems of Mexico and clarify why it is important to understand the role of fire in such ecosystems. We also consider evidence on current fire regimes and management practices, and how they may be impacting different grassy–pine ecosystems.ResultsWe propose a classification of pine ecosystems that acknowledges their huge differences in terms of climate, structure, and composition. Three of these communities have frequently open canopies with grassy understories: piñon woodlands, tropical savannas (Pinus oocarpa savannas) and subalpine woodlands. The majority of the grassy–pine communities are piñon woodlands, mostly in the northern Sierra Madre Oriental. Tropical savannas represent a small proportion of the total, distributed in the plains near the Pacific coast. Subalpine woodlands have the smallest area.ConclusionsThe lack of recognition in Mexico of the diversity of pine‐dominated ecosystems as different types of vegetation with contrasting characteristics and dynamics has resulted in fragmentary information on their natural fire regimes. Evidence suggests that frequent fires may have shaped Mexican grassy–pine ecosystems. Nevertheless, evidence for piñon woodlands is still inconclusive and there may be a large variability in the natural fire regime between sites. Satellite data suggest that current fire frequency in grassy–pine ecosystems is lower than the natural one, and that it increased in recent years just as the budgets for fighting fires diminished in the country. It thus seems that misguided fire suppression policies have strongly altered natural fire regimes.

An assessment of ectoparasites across highland and lowland populations of Leadbeater's possum (Gymnobelideus leadbeateri): Implications for genetic rescue translocations.

Leadbeater's possum (Gymnobelideus leadbeateri) is a nocturnal arboreal marsupial with a restricted range centered on the Victorian Central Highlands, south-eastern Australia. Most populations inhabit wet montane ash forest and subalpine woodland, with one notable exception - a small, outlying and genetically-distinct lowland population inhabiting swamp forest at Yellingbo, Victoria. The species has been listed as critically endangered since 2015. Translocations are the mainstay of critical genetic rescue and this study explores the ectoparasites that are ‘along for the ride’ during translocation activities. Ectoparasites (133 fleas, 15 ticks and 76 mites) were collected opportunistically from 24 Leadbeater's possum colonies during population monitoring and genetic sampling across the lowland and highland populations. The composition of the flea assemblage varied by habitat type. Significantly greater numbers of the general marsupial fleas Acanthopsylla r. rothschildii. and Choristopsylla tristis (as a proportion of total flea numbers) were detected in lowland habitats, compared to highland habitats (Fishers exact test, P < 0.0001). Two host-specific flea species, Stephanocircus domrowi and Wurunjerria warnekei were detected only on possums in highland habitats. As a proportion of total fleas this was significantly different to possums in lowland habitats (Fisher's exact test, P = 0.0042 and P < 0.0001, respectively). Wurunjerria warnekei was suspected to be extinct prior to this study. Ticks (Ixodes tasmanii, n = 15) and mites (Haemdoelaps cleptus, n = 47 and H. anticlea, n = 29) have been identified in Leadbeater's possums historically. The possible causes of the different flea assemblages may be environmental/climatic, or due to the historic geographic division between highland and lowland animals. The planned translocations of highland individuals to lowland habitats will expose lowland individuals to novel species of previously exclusively highland fleas with unknown indirect consequences, thus careful monitoring will be required to manage any potential risks.

Early to late Holocene vegetation and fire dynamics at the treeline in the Maritime Alps

We used pollen, plant macrofossil, and charcoal records to investigate local long-term timberline shifts and changes in vegetation composition in relation to fire activity at the modern upper forest limit (ca. 2,000 m a.s.l.) in the Mont Bego area, Maritime Alps of France and Italy. The area is an important place for Alpine archaeology because it has thousands rock-art carvings whose age cannot be directly assessed. Our new record confirms the occurrence of distinct land use phases (7,450–7,150, 6,200–4,900, and 4,250–3,700 cal bp), as suggested by earlier studies of rock art typology. Moreover, the vegetation reconstruction from macrofossils, with co-dominance of Pinus and Betula, suggests that early Holocene conditions were moister than in drier inner Alpine valleys, where Larix decidua played a more important role, both in the past as well as in modern timberline forests. After 8,000 cal bp, the timberline shifted upwards and mixed Abies alba and Pinus cembra stands established around the study site. These fire sensitive trees were finally replaced during the Bronze Age (around 4,000 cal bp) by L. decidua, which still dominates the subalpine woodlands in the area today. Our study supports the notion that while the range of A. alba has been reduced at the colder end of its natural distribution, that of L. decidua has been widened by land use changes and fire disturbances to create high alpine wood pastures.

Alpine treeline ecotone stasis in the face of recent climate change and disturbance by fire.

How species respond to climate change will depend on biological characteristics, species physiological limits, traits (such as dispersal), and interactions with disturbance. We examine multi-decadal shifts in the distribution of trees at the alpine treeline in response to regional warming and repeated disturbance by fire in the Victorian Alps, south-east Australia. Alpine treelines are composed of Eucalyptus pauciflora subsp. niphophila (Snow Gum, Myrtaceae) species. The location and basal girth of all trees and saplings were recorded across treelines at four mountains in 2002 and 2018. We quantify changes in treeline position (sapling recruitment above treeline) over time in relation to warming and disturbance by fire, and examine changes in stand structure below treeline (stand density, size class analyses). Short-distance advance of the treeline occurred between 2002 and 2018, but was largely restricted to areas that were unburned during this period. No saplings were seen above treeline after two fires, despite evidence that saplings were common pre-fire. Below treeline, subalpine woodland stands were largely resilient to fire; trees resprouted from lignotubers. However, small trees were reduced in number in woodlands when burned twice within a decade. Population dynamics at the alpine treeline were responsive to recent climate change, but other factors (e.g. disturbance) are crucial to understand recruitment trends. Establishment of saplings above treeline was largely restricted to unburned areas. These results indicate fire is a strong demographic filter on treeline dynamics; there is a clear need to frame alpine treeline establishment processes beyond just being a response to climate warming. Long lag periods in treeline change may be expected where recurrent disturbance is a feature of the landscape.

Extensive recent wildfires demand more stringent protection of critical old growth forest

Old growth forests have many key values, but temporal changes across their spatial extent are poorly understood. This includes large parts of Australia and is a major knowledge gap given the extent of human and natural disturbances in the Australian forest estate over past decades. We integrated spatial data on the timing and extent of fire and logging across mapped forest and woodland cover in different Ecological Vegetation Class (EVC) groups to quantify disturbance of the old growth forest and woodland estate in Victoria since 1995, including after the 2019–20 wildfires. We found ~77% of old growth forest and woodlands have been disturbed by fire and logging over the past 25 years. Disturbance was particularly marked in some EVCs, such as the Wet and Damp Forest and the Subalpine Woodlands. In contrast, relatively little of the Modelled Old Growth Forest and Woodland has been disturbed between 1995 and 2020 in other EVCs such as in Plains Woodlands and Heathy Woodlands. Wildfire was the primary driver of disturbance in Modelled Old Growth Forest and Woodland. We argue that a range of strategies is critical to increase protection of undisturbed old growth forest. These include re-assessing disturbance data layers to ensure that areas of old growth that have been burned at low severity are protected, and reducing the size of old growth patches to be conserved. There is also a need to increase levels of protection of young forests to enable them to grow through to an old growth state.

Distinct Drimane Chemotypes in Tasmanian Mountain Pepper (Tasmannia lanceolata): Differences in the Profiles of Pungent Leaf Phytochemicals Associated with Altitudinal Cline.

This study assesses whether the distinct altitudinal cline in leaf morphology (decreased leaf width and length with increased altitude) in Tasmanian mountain pepper (Tasmannia lanceolata) is associated with changes in the leaf chemistry of wild populations from different ecological landscapes and altitudes. The presence of distinct pungent drimane sesquiterpenoid chemotypes was identified: subalpine woodland and wet sclerophyll forest chemotypes. Isolation studies and analysis of extracts revealed that wet sclerophyll forest T. lanceolata populations featured polygodial as the principal terpenoid, with profiles similar to the commercial cultivars sampled. In contrast, the subalpine woodland populations contained the drimane sesquiterpenoids 1β-acetoxy-9-deoxyisomuzigadial and 3β-acetoxydrimenin and the conspicuous absence of the pungent principle polygodial.

The effects of fire history on hollow-bearing tree abundance in montane and subalpine eucalypt forests in southeastern Australia

Hollow-bearing trees provide critical habitat resources for forest fauna, yet there is evidence of a ubiquitous decline in the large, old trees most likely to provide this resource. Fire can influence the formation and persistence of tree hollows. In this study, we investigated the effects of stand-level fire history and individual tree attributes on tree hollow abundance in two forest types in Namadgi National Park in the Australian Capital Territory: subalpine woodlands dominated by Eucalyptus pauciflora Sieber ex Spreng (snow gum); and tall-open E. delegatensis R.T.Baker (alpine ash) montane forest. These forests can be differentiated by their distinct response to fire; E. pauciflora resprouts following fire and E. delegatensis reproduces exclusively via seed. We employed a ground-based approach to measure 1044 trees across 36 sites selected by forest type and fire history as recorded since 1920. For both species, hollow abundance decreased with total fire count at stand level and increased for E. delegatensis in response to an extensive wildfire that occurred in the study area in 2003. The probability of a tree containing a hollow increased with tree diameter and if the tree was dead. Our results show that fire frequency and severity have strong implications for tree hollow abundance in montane and subalpine eucalypt forests.

Autosuccession in alpine vegetation: Testing the concept on an altitudinal bioclimatic gradient, Jotunheimen, southern Norway

Specific tests of autosuccession (equivalent to non-replacement change in species composition) are made, in which pioneer communities on roadside verges and areas of patterned ground disturbed by cryoturbation are compared with mature communities on a bioclimatic gradient from sub-alpine woodland (850 m a.s.l) to high-alpine fjellfield (2200 m a.s.l). Autosuccession is quantified for the first time using community similarity coefficients and indices of pioneer persistence and importance, which measure nominal- or ordinal-scale differences in species composition between 65 paired pioneer and mature communities. Linear relationships to altitude, with coefficient and index values of ~90–100% in the upper part of the high-alpine belt to ~10–20% in the sub-alpine zone, indicate a continuum from autosuccession to relay succession (the latter characterised by high species turnover and replacement change). Values based on ordinal-scale data are generally ~10% lower than those based on nominal-scale data and use of pioneer sites from roadside verges result in a ~20% offset relative to pioneer sites from sorted circles (the latter comparison reflecting the effect of substrate differences). Autosuccession appears to be characteristic only at altitudes >2000 m a.s.l. in the upper high-alpine belt. Replacement change increases in importance as a constituent of mixed-mode succession through the conventional mid- and low-alpine belts. Spatial variation in the nature of primary succession along the bioclimatic gradient supports a geo-ecological model of succession with predominantly allogenic controls (climatic stress and high levels of substrate disturbance by cryoturbation) at high altitudes and increasing autogenic controls (biological interactions and substrate stability) at lower altitudes.

Coupled human-climate signals on the fire history of upper Cachapoal Valley, Mediterranean Andes of Chile, since 1201 CE

Abstract The long-term history of fire regimes in the Mediterranean Andes of Chile is almost unknown. Subalpine woodlands of Austrocedrus chilensis include long-lived trees resilient to low-intensity fires, which can provide valuable tree-ring-based information about fire history. In this work, we performed an annually resolved multicentury reconstruction of past fires from fire-scar records identified in relict Austrocedrus wood found on steep highly-eroded and rocky slopes with coarser fuel structure in the upper Cachapoal Valley, central Andes of Chile. We compared this fire record with historical land-use changes and extensive reconstructions of regional precipitation and temperature, as well as large-scale climatic patterns. The highest fire frequencies were recorded in the Spanish settlement period (1541–1750), when land-clearing activities, cattle ranching, agriculture, and mining practices became widespread after the Spanish conquest. At an interannual time scale, fire occurrence and precipitation were unconnected during the Spanish settlement. By contrast, in the indigenous period (1200–1540), under the influence of the aboriginal Chiquillanes people, fires occurred in wet years with high vegetation productivity. In the livestock grazing period (1751–1950), when large cattle ranches were established, fires occurred in dry years after a wet year. Fires in this period were likely ignited under conditions of high fuel flammability to improve plant production and promote intensive livestock grazing. At a multidecadal time scale, fires were more frequent in cold periods throughout the whole record. These findings suggest that herbaceous fuel accumulation and flammability, modulated by climate variation and human land uses, were the main factors promoting fires spread in this Mediterranean subalpine area. Our research emphasizes the importance of relict Austrocedrus wood for fire history reconstruction and expands knowledge about fire regime shifts over the past eight centuries in southern South America.

Cirsium greimleri

The newly described diploid species Cirsium greimleri (2n = 34; 2C = 1929.1‘60.6 Mbp) belongs to Cirsium sect. Cirsium and is distributed sparsely throughout the Eastern Alps and Dinarides, whereas the closely related tetraploid vicarious species C. waldsteinii (2n = 68; 2C = 3682.3‘69.8 Mbp) is endemic to the south-eastern Carpathians. The ploidy, genetic and morphological separation of both taxa is confirmed using flow cytometry, AFLP and morphometric analyses of 169 plants from 27 populations covering representatively distribution ranges of the respective species. The species differ in flower colour, with those of C. greimleri ruby red to brownish-purple and those of C. waldsteinii pinkish-purple to purple. The colour difference remains consistent when both species are cultivated together under the same conditions. Differences between the species in the size of the stomata, achenes, corollas, styles and pappus are statistically significant and congruent with differences in the ploidy level. Because both species are gynodioecious (their populations contain female and hermaphrodite plants), the generative features should be compared carefully with respect to gender (e.g. females with females) because the between-gender differences within the same species could be larger than the between-species differences. The basal and median cauline leaves of C. waldsteinii are narrower and more deeply lobed than those of C. greimleri. A slight difference in the flowering period is detected when both species are cultivated together, with C. waldsteinii flowering two weeks earlier than C. greimleri. Both species share ecological/ habitat preferences for subalpine woodland tall-forb vegetation. While C. waldsteinii hybridizes extremely rarely with co-occurring diploid congeners, C. greimleri produce hybrids very often, which increase the risk of its extinction via genetic erosion.

Resource use by old and modern dairy cattle breeds on semi-natural mountain pastures, Central Norway

The objective of this pilot study was to compare resource use in a mountainous summer farming landscape between old and modern dairy cow breeds during a five-day period. The modern breed used a larger part of the landscape than the old breed, most likely due to differences in habitat patterns. The old breed group preferred semi-natural pastures, while the modern breed preferred overgrown semi-natural meadows, intermediate fen, intermediate wooded fen, and grass-rich sub-alpine birch woodland. Both breeds spent most time grazing grasses, but the modern breed showed a higher frequency of grasses and Vaccinium myrtillus in its diet, while the old breed showed a higher frequency of bushes and trees. The pilot study shows some trends supplementing and strengthening earlier results on how modern and traditional cattle breeds are differing in their impact on vegetation based on their use of space and their different diets.

Responsiveness to acoustic stimulation, distribution and habitat preferences of the Grey-headed Woodpecker, Picus canus, and the Three-toed Woodpecker, Picoides tridactylus, in Friuli-Venezia Giulia (North-eastern Italy)

The study was carried out from 2003 to 2011 with the aim of determining the responsiveness to acoustic stimulation, the distribution and the habitat preferences of &lt;em&gt;Picus canus&lt;/em&gt; and &lt;em&gt;Picoides tridactylus&lt;/em&gt; in Friuli-Venezia Giulia (NE Italy). &lt;em&gt;P. canus&lt;/em&gt; resulted as being more responsive than &lt;em&gt;P. tridactylus&lt;/em&gt; to conspecifics stimulation, responding in 13.23% of the points where a stimulus was emitted, against 7.65% of the other species. In both taxa, when there was a response, it was predominantly by the male birds. The most frequent type of response in &lt;em&gt;P. canus&lt;/em&gt; was song, heard in 57.89% of the points, while for &lt;em&gt;P. tridactylus&lt;/em&gt;, it was drumming, which was heard in 65.38% of the points. For both species (especially for P. tridactylus), a tendency was recorded to expand the range and to occupy new areas within the known range. &lt;em&gt;P. canus i&lt;/em&gt;n Friuli-Venezia Giulia was found from altitudes close to the sea level up to the treeline (range 0-2000 m a.s.l.), while &lt;em&gt;P. tridactylus&lt;/em&gt; was found in montane and subalpine woodlands (range 800- 2000 m a.s.l.). The observations of P. canus were obtained at a mean altitude of 977 m a.s.l. (± 402 SD), located in the altitudinal belt dominated by Fagus sylvatica L., which is present in more than half of the woodlands in which the woodpecker was found.&lt;em&gt; P. tridactylus&lt;/em&gt; was discovered at a mean altitude of 1424 m a.s.l. (± 246 SD), located in the altitudinal belt dominated by Picea abies (L.) H. Karst., which is present in almost 90% of the woodlands in which this species was found. In some areas, densities of 0.67-2.26 territories/100 ha were obtained for&lt;em&gt; P. canus&lt;/em&gt; and 0.16-0.40 territories/100 ha for &lt;em&gt;P. tridactylus.&lt;/em&gt; In Friuli-Venezia Giulia, a population of 320-390 pairs of P. canus and 45-60 pairs of P. tridactylus has been estimated, with an approximate 15% increase of&lt;em&gt; P. canus&lt;/em&gt; compared to the beginning of the century, and just over 60% for the other species. Finally, some aspects concerning conservation-related problems are reported.

Vegetation and environments since the Last Glacial Maximum in the Southern Tablelands, New South Wales

ABSTRACTRegional changes in vegetation and environment in the last 16 ka have been reconstructed from Micalong Swamp and Willigobung Swamp (35°S) on the western Southern Tablelands of New South Wales (NSW). Micalong Swamp lies at 980 m above sea level (a.s.l.), which is close to the subalpine treeline at this latitude. Willigobung Swamp (780 m a.s.l.) approaches the modern ecotone between dry and wet montane forest formations. The sites are sensitive to shifts in temperature and precipitation and are the first reported pollen records from the western montane slopes of NSW. A radiocarbon‐based chronology indicates that Micalong Swamp was a swampy, gravel floodplain surrounded by alpine grassland before 16.1 ka. Subalpine woodland may have become established at 1000 m by 16–14 ka. Organic fen sedimentation developed &lt;11.8 ka at Willigobung, and ∼11.7 ka at the higher elevation Micalong Swamp. Wet forest elements were present at both sites around 10 ka and persisted for 3–4 ka. Sedimentation in a shallow lake or fen between 10 and 8 ka supports this evidence for wetter conditions in the early Holocene. In the late Holocene an expansion of subalpine flora between 2.7 and 0.9 ka preceded by shallow lake/fen sedimentation is consistent with regional evidence for neoglacial cooling.

Habitat and food preferences of the endangered Palila (Loxioides bailleui) on Mauna Kea, Hawai‘i

Seeds and flowers of the leguminous māmane (Sophora chrysophylla) tree are the primary food resource of the federally endangered Palila (Loxioides bailleui; Fringillidae: Drepanidinae), which is now restricted to dry subalpine woodland on Mauna Kea Volcano on the island of Hawai‘i because of centuries of habitat degradation by non-native ungulates. Palila are morphologically and behaviorally adapted to consume māmane seeds by grasping seed pods with their feet and opening pods with stout bills and demonstrate limited ability to exploit alternative food resources. This degree of single species dependency is rare among birds and illustrates unique adaptations that also occurred in other Hawaiian species that are now extinct. In mixed-woodland with co-dominant naio (Myoporum sandwicense), Palila spent 1.7–3.9 times longer in māmane than in naio during foraging observations where naio was 1.3–4.6 times as dense as māmane. Naio fruit was readily available, but it comprised proportionally <11% of food items taken by Palila. Although māmane flowers were more abundant than māmane pods throughout this study except at one lower-elevation mixed-woodland site, Palila spent more time foraging on pods than flowers in both māmane woodland and mixed-woodland, but consumed more flowers than pods in mixed-woodland. Insects, which have been reported as an important component of the diet of Palila, were apparently taken rarely in this study. Protecting and restoring māmane in woodlands adjacent to the current range of Palila will benefit their recovery, allowing them to exploit increased food availability in areas of their former range.

Response of palila and other subalpine Hawaiian forest bird species to prolonged drought and habitat degradation by feral ungulates

Extinction has claimed half of all historically-known Hawaiian passerines, and today many extant species are increasingly threatened due to the combined effects of invasive species and climate change. Habitat disturbance has affected populations of feeding specialists most profoundly, and our results indicate that specialists continue to be most vulnerable, although even some abundant, introduced, generalist species also may be affected. Surveys of passerines during 1998–2011 in subalpine woodland habitat on Mauna Kea Volcano, Island of Hawai′i, revealed that the abundance of the critically endangered palila (Loxioides bailleui), a seed specialist, declined by 79% after 2003. The ′akiapōlā′au (Hemignathus munroi), an endangered specialist insectivore, was not detected in the survey area after 1998. The Hawai′i ′amakihi (Hemignathus virens virens), a generalist feeder and the most abundant species on Mauna Kea, was the only native species to maintain a stable population. The Japanese white-eye (Zosterops japonicus), a well-entrenched generalist and one of the three most common introduced species, declined. Drought prevailed in 74% of months during 2000–2011, and dry conditions contributed to the recent decline of the palila by reducing the annual māmane (Sophora chrysophylla) seed pod crop, which influences palila breeding and survival. Sustained browsing by introduced ungulates also lowered habitat carrying capacity, and their elimination should reduce the effects of drought and promote forest restoration. Our results illustrate how the feeding ecology of a species can influence its response to interacting environmental perturbations, and they underscore the value of long-term monitoring to detect population trends of sensitive species.