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Direct studies of mammalian carnivores are challenging due to the animals' secretive nature and the high costs associated with their capture and handling. Use of noninvasive hair sampling to survey these reclusive species has great potential as an alternative, with wide applicability in ecology and conservation. Hair-trapping has been extensively used for focal studies of temperate mammals, but its use and applicability as a means to survey mammals in tropical environs has never been addressed. We evaluated the effectiveness of 2 hair-trap types and 2 scents along an elevational gradient within El Cielo Biosphere Reserve (ECBR, Mexico) to detect presence of carnivores. Hair-traps that used roofing nails as a hair-collecting surface collected more hairs and detected a greater number of species than did hair-traps that used velcro strips. Different scent treatments (commercial fragrance and catnip oil) did not differ for these same variables. Of successful nail hair-traps, 60% collected ≥20 hairs (...

Elevational pattern in reptilian species richness and species turnover was studied on two Dinaric mountains along the eastern Adriatic coast: northern Mt. Velebit and Mt. Biokovo. Both mountains had similar numbers of species (20 and 22, respectively) and showed a gradual decline in species richness with increasing elevation. Lizard species richness was less dependent on elevation than that of snakes. Pattern of species turnover among 200 m elevational intervals peaked at high elevations in Mt. Velebit and at mid‐elevations in Mt. Biokovo. Two elevational zones (0–400 m and 1400–1600 m) contained 100% of a local species pool in Mt. Velebit and 91% in Mt. Biokovo. Effective conservation of reptilian species richness in the Dinaric Alps should thus focus on extreme altitudinal zones.

Sprint speed has a capital relevance in most animals' fitness, mainly for fleeing from predators. Sprint performance is maximal within a certain range of body temperatures in ectotherms, whose thermal upkeep relies on exogenous thermal sources. Ectotherms can respond to diverse thermal environments either by shifting their thermal preferences or maintaining them through different adaptive mechanisms. Here, we tested whether maximum sprint speed of a lizard that shows conservative thermal ecology along a 2200-meter elevational gradient differs with body temperature in lizards from different elevations. Lizards ran faster at optimum than at suboptimum body temperature. Notably, high-elevation lizards were not faster than mid- and low-elevation lizards at suboptimum body temperature, despite their low-quality thermal environment. This result suggests that both preferred body temperature and thermal dependence of speed performance are co-adapted along the elevational gradient. High-elevation lizards display a number of thermoregulatory strategies that allow them to achieve high optimum body temperatures in a low thermal-quality habitat and thus maximize speed performance. As for reproductive condition, we did not find any effect of it on sprint speed, or any significant interaction with elevation or body temperature. However, strikingly, gravid females were significantly slower than males and non-gravid females at suboptimum temperature, but performed similarly well at optimal temperature.

Comparing elevational gradients across a wide spectrum of climatic zones offers an ideal system for testing hypotheses explaining the altitudinal gradients of biodiversity. We document elevational patterns of lizard and snake species richness, and explore how land area and climatic factors may affect species distributions of lizards and snakes. Our synthesis found 42 lizard species and 94 snake species known from the Hengduan Mountains. The lizards are distributed between 500 and 3500 m, and the snakes are distributed between 500 and 4320 m. The relationship between species richness and elevation for lizards and snakes is unimodal. Land area explains a significant amount of the variation in lizard and snake species richness. The cluster analysis reveals pronounced distinct assemblages for lizards and snakes to better reflect the vertical profiles of climate in the mountains. Climatic variables are strongly associated with lizard and snake richness along the elevational gradient. The data strongly implicate water availability as a key constraint on lizard species richness, and annual potential evapotranspiration is the best predictor of snake species richness along the elevational gradient in the Hengduan Mountains.

Rana chensinensis (David, 1875) is a temperate anuran endemic to northern China. We examined differences in demographic traits of the populations from three elevations (1400, 1700, and 2000 m) along a montane river in 2002. We found that frogs from higher elevations had delayed maturity, a larger size at maturity, and slower growth rates compared with frogs at lower elevations. This life-history model is similar to observations of other amphibians living in montane areas. However, discordance with the expected model occurred between neighboring populations and the variation was sex-specific. Mid-elevation adult males were significantly older and larger than their low-elevation congeners, but they were statistically similar in age and size to frogs from high elevations; females from mid elevations were not statistically different in age and size from females from our low-elevation site, but they were significantly younger and smaller than high-elevation females. These variations may be related to sexual differences in life-history strategies, which might not covary systematically when elevational gradients are set at a finer scale. At each elevation, the sex ratio was skewed towards females; females also matured later, lived longer, and were larger. Age was a major factor related to size, but other factors played a role in shaping size differences both between populations and between sexes.

We studied frog biodiversity along an elevational gradient in the Hengduan Mountains, China. Endemic and non-endemic elevational diversity patterns were examined individually. Competing hypotheses were also tested for these patterns. Species richness of total frogs, endemics and non-endemics peaked at mid-elevations. The peak in endemic species richness was at higher elevations than the maxima of total species richness. Endemic species richness followed the mid-domain model predictions, and showed a nonlinear relationship with temperature. Water and energy were the most important variables in explaining elevational patterns of non-endemic species richness. A suite of interacting climatic and geometric factors best explained total species richness patterns along the elevational gradient. We suggest that the mid-domain effect was an important factor to explain elevational richness patterns, especially in regions with high endemism.

Determinate growth involves cessation of leaf formation prior to the end of the growing season, whereas indeterminate growth involves leaf formation for as long as environmental conditions allow. Quaking aspen ( Populus tremuloides Michx.) has been described as having both types of growth. This variation is partially due to canopy bud position, but environmental factors may also contribute. In this study, buds from the same canopy position of aspen trees in northern Colorado, USA, exhibited less neoformation with increasing elevation (R2= 0.78). Evidence suggests that this is primarily a response to the characteristically cooler temperatures and shorter growing seasons of higher elevations.

Aim This research investigates changes in orchid species composition and diversity, plant breeding system and floral traits along an elevational gradient spanning 2300 m (200‐2500 m).

Along an elevational gradient on SW Utah, sagebrush lizards (Sceloporus graciosus) exhibit an unexpected pattern of growth. Lizards from a high elevation population grow faster than lizards from two populations at lower elevations despite shorter daily and seasonal activity. Results from a common environment study of growth suggest that the differences in growth are not due to adaptation to local environmental conditions. In this study, I test the hypothesis that higher growth rates in lizards from high elevation may be attributable to reduced resting metabolic expenditure compared to that of lizards from populations at two lower elevations. Resting metabolic rates were measured for individuals from each of the study populations across different times of day and over a broad range of temperatures. Under the same laboratory conditions, field-caught lizards from the high elevation population exhibited lower metabolic rates when compared to lizards from lower elevations. Daily resting metabolic expenditures were calculated using the observed metabolic rates coupled with estimates of daily activity. Daily resting metabolic expenditure was 50% greater for individuals from the two lower elevation populations, which could result in 12.5% more energy that could be potentially allocated to growth for lizards from high elevation. Such energetic savings may be able to explain differences in the patterns of growth observed in nature.

We studied the concentration of leaf N and C among 183 fern species along an elevational gradient at 1700 to 3400 m in humid montane forest in the Bolivian Andes at different levels of taxonomic resolution. For two species of Elaphoglossum sampled 8 and 14 times, respectively, there were no elevational trends. Similarly, a contrast of 22 species with wide elevational amplitudes sampled at their highest and lowest locations did not show any change in C or N contents, or in C:N ratios with elevation. At the community level, however, the mean values of C:N ratios for (a) all species found at a given elevation showed a significant decline with increasing elevation and (b) among epiphytic species, higher ratios (i.e., lower relative N content) than among terrestrial species at the same elevation. These trends were opposite to those of the upper soil layer, in which C:N ratios increased with elevation.

We studied floral visitors and traits of claret cup cactus (Echinocereus coccineus) at six sites and three elevations along a 1200-m gradient in the Chiricahua Mountains, Arizona. Although elevation affected flowering time, it had little effect on the size distribution or taxonomic classes of visitors. Hummingbirds visited at all sites and relative visit rates of large (7 g) and small (3 g) hummingbirds were similar at each elevation. Males of large species visited more commonly than females, whereas the reverse was true for small hummingbirds. Halictid bees visited commonly at all elevations, but other insects were rare. The survey of visitors revealed no elevation-related patterns that would select for differentiation in floral traits. However, flower length and correlated traits (distance from nectar chamber to anthers and stigma) increased significantly with elevation, with maximum differences of 15–18%, indicating a possible advantage of large flower size at higher elevations. Flower width a...

In order to better understand the influence of short elevational gradient on the attributes of bryophyte communities, we examined the bryophyte flora within six elevational belts (10, 50, 400, 800, 950, and 1170 m a.s.l.) on a mountain in the Atlantic Forest in southeastern Brazil. Ten subplots (10 × 10 m) distributed randomly in 1 ha forest plot of forest at each elevation were surveyed. A total of 253 species were encountered and the richness did not vary depending significantly on elevation. The floristic similarities of the elevational belts were high > 50%, with the exception of the Mountaintop forest (< 35%), and the classification analyses indicated groups defined by Atlantic Forest vegetation types. Endemism demonstrated a positive correlation with elevation, while the amplitudes of the phytogeographical patterns of the species diminished with increasing elevation. The dioicous condition predominated in all of the elevational belts, and the dioicous/monoicous ratio showed an inverted-parabolic pattern along the gradient. Data concerning bryophyte species richness and distributions will be useful in future projects monitoring the effects of climate change on tropical forests.

Bergmann's Rule predicts larger body sizes in colder habitats, increasing organisms' ability to conserve heat. Originally formulated for endotherms, it is controversial whether Bergmann's Rule may be applicable to ectotherms, given that larger ectotherms show diminished capacity for heating up. We predict that Bergmann's Rule will be applicable to ectotherms when the benefits of a higher conservation of heat due to a larger body size overcompensate for decreased capacity to heating up. We test this hypothesis in the lizard Psammodromus algirus, which shows increased body size with elevation in Sierra Nevada (SE Spain). We measured heating and cooling rates of lizards from different elevations (from 300 to 2500 m above sea level) under controlled conditions. We found no significant differences in the heating rate along an elevational gradient. However, the cooling rate diminished with elevation and body size: highland lizards, with larger masses, have a higher thermal inertia for cooling, which allows them to maintain heat for more time and keep a high body temperature despite the lower thermal availability. Consequently, the net gaining of heat increased with elevation and body size. This study highlights that the heat conservation mechanism for explaining Bergmann's Rule works and is applicable to ectotherms, depending on the thermal benefits and costs associated with larger body sizes.

Modern pollen-rain studies are crucial for the calibration and interpretation of fossil pollen records. In East Africa, numerous pollen records provide important insights into the impact of human populations and climate change on tropical ecosystems. However, the confident use of fossil pollen data to reconstruct vegetation and climate dynamics requires well-founded knowledge regarding the relationship between pollen deposition and modern- day vegetation, which is still deficient for large parts of the African continent and non-existent for the tropical East African Mountains. In this study, we investigated the relationship between vegetation and modern pollen-rain along the elevational gradient of Kilimanjaro. We apply multivariate data analysis to assess the relationship between vegetation and modern pollen-rain and quantify the representativeness of forest zones. We further assessed the taxonomic level needed for differentiation between forest zones based on the modern pollen-rain assemblage, biodiversity patterns and pollen and spore drift. In the montane vegetation of Kilimanjaro, it is sufficient to analyse the pollen-rain on plant family level in order to derive the forest zone of the surrounding vegetation. Along this elevational gradient, pollen and spore dispersal is strongly influenced by regional wind patterns, but their deposition reflects the diversity patterns of the surrounding vegetation. This study represents the first statistical analysis of pollen vegetation relationship along an elevational gradient in Africa. Hence, this paper improves confidence in interpretation of palynological records from the tropical East African Mountains and may refine past climate reconstructions for a more accurate comparison of data and modelling. peerReviewed

We evaluated species‐environment relationships within pinon‐juniper woodlands in northern New Mexico (United States) using canonical correspondence analysis (CCA). The first CCA axis was associated primarily with elevation. Our results showed separation between pinon and juniper along the elevation gradient, as expected: pinon is relatively more dominant at higher sites, whereas juniper is relatively more dominant at lower sites. To examine how this pattern of dominance might emerge with time, we plotted the position of centroids for three pinon and juniper size classes along the first CCA axis. We found that small pinons and junipers were distributed relatively uniformly across the gradient, whereas large pinons and junipers were strongly segregated along the gradient, with intermediate‐sized pinons and junipers intermediate on the CCA axis between small and large. This produced a pattern of increased divergence between the two species that increased with size. We suggest that this pattern emerges as a r...

Heterogeneity patterns in semi-natural grasslands were studied within 20 sites at 4 different elevational levels ranging from 530 m a.s.1. at level 1 (southern boreal region) to 1230 m a.s.1. at level 4 (low alpine region) in Vang, southern Norway. Vegetational heterogeneity decreased with elevation for vascular plants. Cryptogam species increased in heterogeneity at mid-elevational levels (750 and 915 m a.s.1.), but heterogeneity decreased again at level 4. Mean values of soil nutrients and other soil variables (e.g. loss on ignition), and their heterogeneity increased with elevation, while pH showed a decrease for both parameters. The general increase in environmental heterogeneity in the soil was not reflected in vascular plant heterogeneity because soil variables explained 40 % variation at both level 1 and 4. However, the relative differences among levels suggest that vascular plant species patterns were more sensitive to soil heterogeneity at lower elevational levels. Soil variables were also relatively more important in structuring cryptogam species at higher elevations (level 3 and 4) compared to vascular plant species. The discrepancy between vascular plants and cryptogams are also shown in the relationship between heterogeneity and diversity. Gamma diversity decreased with decreasing heterogeneity of vascular plants, while the highest value of large scale cryptogam diversity corresponded with the lowest heterogeneity value at level 4. Alfa-diversity peaked at an intermediate level of heterogeneity for vascular plants while alfa-diversity of cryptogams decreased with increasing values of heterogeneity.

Summary 1 It is unclear whether soil seed banks in alpine environments are a result of selection for extended seed dormancy, of ideal conditions for seed preservation in the soil, or a combination of both. 2 The nature of the soil seed bank was investigated in the perennial herb Phacelia secunda (Hydrophyllaceae) through reciprocal burial experiments using seeds obtained from populations growing at 1600, 2200, 2900 and 3400 m a.s.l. in the mediterranean Andes of central Chile. At the four elevations, six replicates of 50 seeds each, from each of the four elevational sources, were buried at 5 cm depth in mesh envelopes, placed in wire cages to protect against predation. Seeds were retrieved 1, 2 and 3 years after burial, and numbers of ungerminated seeds, and of those that remained viable, were determined. 3 At all elevations of seed burial, increasing proportions of seeds remained ungerminated, and proportionately more of the ungerminated seeds remained viable, as elevation of source of seed increased. For seed from low elevation, more seeds remained viable in the soil at the higher burial sites. However, for the seeds from higher elevation sources, seeds remaining viable were similar in number at all sites for seed burial. Half-lives of seed buried at the source elevation, calculated from the log-logistic distribution, increased with elevation, and ranged from 188 days at 1600 m to 354 days at 3400 m. 4 The results suggest that the propensity to form a persistent seed bank in P. secunda increases with elevation. Seeds from the highest elevations had the longest persistence, and this was largely unaffected by soil preservation conditions. Seeds from lower elevations survived for less time, and this was modifiable by preservation conditions. These results suggest that both selective effects and soil conditions may be involved in soil seed bank expression in the alpine environment.

In this study, we assess the risks of global warming on distributions of individual tree species in Switzerland. Applying a spatially explicit model, tree occurrence is predicted as a function of high resolution and physiologically relevant biophysical variables. The study shows that warming only slightly alters the overall abundance of tree species. However, the preferred temperature regimes are unevenly distributed along an elevational gradient, and the sensitivity to temperature varies considerably between the species. As a result, major reorganizations of forests in montane and subalpine belts are expected, i.e., a segregation of the core distributions of Fagus sylvatica and Picea abies is observed. Tree distribution potentials near timberlines, however, remain roughly the same.

(2000). Organic matter dynamics along a stream-order and elevational gradient in a southern Appalachian stream. SIL Proceedings, 1922-2010: Vol. 27, No. 3, pp. 1341-1345.

Summary Sun and shade leaves of beech were collected along an elevational gradient in the Hunsruck (Rhineland-Palatinate). Leaf area, specific leaf weight and the flavonoid contents (measured as absorbance of methanolic extracts) were determined. Sun leaves exhibited higher absorbances at 280 and 320 nm per unit leaf area and per gram dry mass than shade leaves. UV-B absorbance of the sun leaves increased with increasing elevation. A positive correlation was found between the absorbance of sun leaves at 280 nm and 320 nm and specific leaf weight. A change in mineral nutrition (measured as mineral contents of the leaves) along the elevational gradient was not determined. It is supposed that the increase in absorbance of ultraviolet-B-radiation is caused by an increase in ultraviolet-B radiation in the Hunsruck.

SummaryIn this study I compare bird communities along an elevational gradient in an Atlantic forest remnant (Pico do Corcovado in Ubatuba) in coastal Sao Paulo state, Brazil. Forests at low elevations are structurally more complex and more diverse in plant species than those along the slopes and at higher elevations in this remnant. Consequently it is hypothesized that low elevation forests contain a greater diversity of bird species. Results from the study in the Corcovado area show clear differences in the distribution of forest birds along the elevational gradient from both qualitative and quantitative aspects. The structurally more complex forest at low elevations contains the most diverse avifauna, including several of the rarest and most threatened species. The importance of this remnant as a whole is apparent due to the high diversity observed (254 species), the high proportion of endemic species, and the extent to which the avifauna is endangered. Protection of forests at all elevations along the Serra do Mar is required to maintain diversity of bird species, particularly the many endemic and endangered species restricted to specific elevations.

Ant communities were surveyed along an elevational gradient in the Philippines extending from lowland dipterocarp forest (250 m elevation) to mossy forest (1750 m). Standardized pitfall trapping in arboreal and terrestrial microhabitats at seven sites yielded 51 species. Collecting by hand at five of the sites yielded 48 species. The two methods produced substantially different assemblages, with only 22 species (29%) taken in common. Only a fraction of the total ant community appeared to be sampled at most of the sites. Measures of species richness and relative abundance peaked at mid-elevations and declined sharply with increasing elevation. Ants were extremely rare above 1500 m elevation. Arboreal ants were trapped much less frequently than terrestrial ants at all sites. Ant species that were abundant had broader elevational distributions than those that were less common, but most species were rare and occurred at only one or two sites. The elevational patterns for ants are largely the inverse of those documented for Philippine small mammals which reach their greatest diversity and abundance at high elevations where ants are rare. This suggests that the two groups may interact competitively. Some of the patterns observed or inferred from this study may apply to tropical ant communities in general, and are presented as series of testable hypotheses as a guide and stimulus for future research.

Mycorrhizal fungi are crucial for the ecological success of land plants, providing their hosts with nutrients in exchange for organic C. However, not all plants are mycorrhizal, especially ferns, of which about one-third of the species lack this symbiosis. Because the mycorrhizal status is evolutionarily ancestral, this lack of mycorrhizae must have ecological advantages, but what these advantages are and how they affect the competitive ability of non-mycorrhizal plants under natural conditions is currently unknown. To address this uncertainty, we studied terrestrial fern assemblages and species abundances as well as their mycorrhization status, leaf nutrient concentration and relative annual growth along an elevational gradient in the Ecuadorian Andes (500–4,000 m). We surveyed the mycorrhizal status of 375 root samples belonging to 85 species, and found mycorrhizae in 89 % of the samples. The degree of mycorrhization decreased with elevation but was unrelated to soil nutrients. Species with mycorrhizae were significantly more abundant than non-mycorrhizal species, but non-mycorrhizal species had significantly higher relative growth and concentrations of leaf N, P, Mg, and Ca. Our study thus shows that despite lower abundances, non-mycorrhizal fern species did not appear to be limited in their growth or nutrient supply relative to mycorrhizal ones. As a basis for future studies, we hypothesize that non-mycorrhizal fern species may be favoured in special microhabitats of the forest understory with high soil nutrient or water availability, or that the ecological benefit of mycorrhizae is not related to nutrient uptake but rather to, for example, pathogen resistance.

BACKGROUND: Thermal gradients along changes in elevation in mountainous environments are reflected by different biotas. Although there have been studies of elevation variation in bat assemblages in summer, winter changes in the same gradients remain unknown. METHODOLOGY/PRINCIPAL FINDINGS: The objective of this study was to document changes in the species composition of bats hibernating in caves along a temperate elevational gradient. We studied 70 caves between from 300 m to 1,930 m altitude along a slope of the Carpathian Mountains in southern Poland. We recorded changes in bats, including species richness, abundance, altitudinal distribution and dominance during consecutive winters between 2003 and 2009. Similarity of dominance of faunal structure was assessed by using the Bray-Curtis similarity index. We used the generalised additive model and rarefaction to study the variation in species richness, and generalized additive mixed models to examine the effect of abiotic factors on the qualitative and quantitative structure of bat assemblages. During 351 surveys we recorded 13,856 hibernating bats from 15 species. Species richness peaked around mid-elevation (1,100-1,400 m a.s.l.) with richness declining at both higher and lower elevations. Based on the results of a cluster analysis, we could distinguish among four altitudinal zones that differed in species richness and dominance structure. CONCLUSIONS/SIGNIFICANCE: This is the first study documenting changes in species richness and variation of structure of bats hibernating in caves along an elevational gradient. The most surprising and key finding is the fact that changes in the structure of assemblages of hibernating bats along the altitudinal gradient occurred in jumps, forming zones similar to those observed in the vegetation zones. Moreover, species richness and dominance structure of assemblages of hibernating bats in the mountains depended not only on location above sea level, but also on local geomorphologic conditions which strongly affected the microclimate of the caves.

The aim of this paper is to propose the use of chorotype analysis of species assemblages on an elevational gradient to detect the main historical and ecological factors responsible for current faunal settings. A comprehensive faunistic database was used to assess species abundance across 100 m belts in Latium (Central Italy). Species were assigned to chorotypes according to their ranges. Entropy and evenness indices were applied to both species abundances and chorotype frequencies recorded in each belt. Both species and chorotype entropy decreased with elevation, whereas species and chorotype evenness increased. Chorotypes centred on the Mediterranean basin decreased with increasing elevation, chorotypes centred in Europe and Asia had similar frequencies among belts and endemic species increased with elevation. A cluster analysis with species presence/absence data, revealed three main clusters grouping respectively: i) all belts above 1700 m; ii) belts between 901 and 1500 m; and iii) belts between 0 and 900 m. An analysis based on chorotype frequencies produced very similar results. We can conclude that: high elevation assemblages are less diversified, but more balanced than lowland assemblages, in terms of both species and chorological composition. Belts similar in species composition (presence/absence) are also similar in zoogeographical composition (frequency of chorotypes). This indicates that elevation is a factor that strongly selects species’ attributes and especially their geographical distribution. Variations in chorotype composition along an elevational gradient may be used to trace the history of biotas.

Predation could be responsible for habitat partitioning by species if different species are safest from predation in different habitats. Alternatively, predation cannot be responsible for habitat partitioning if all species rank the safety of habitats similarly. I developed predictions to test these two hypotheses, using data on the rates at which animals scan the environment for predators while they forage. Preliminary results suggest that predation is unlikely to be responsible for the habitat preferences of sparrow species win- tering along an elevational gradient in the Sonoran Desert of southern California, USA. Two predictions can be tested using vigilance behavior. (1) If species differ in which habitats they are safest from predation, some species will experience increased risk when moved from one habitat to another, whereas other species will experience decreased risk; changes in vigilance levels between habitats will be inconsistent among species. (2) If species are safest in the same habitat, they will experience similar changes in risk between habitats, and should exhibit similar changes in vigilance levels between habitats. Sage Sparrows (Amphispiza belli) and Black-throated Sparrows (A. bilineata) spend the winter in different habitats. I recorded vigilance levels in each habitat while birds foraged on naturally occurring seeds in a portable aviary. Sage Sparrows and Black-throated Spar- rows exhibited similar changes in vigilance between habitats, suggesting that these two species are safest in the same habitat, and that predation is unlikely to explain their habitat preferences. Also, I tested and found support for the prediction from vigilance theory that food abundance affects vigilance level. Vigilance declined in response to increased foraging patch profitability, counter to the intuitive prediction that increased food abundance relaxes the threat of starvation, allowing more time for vigilance. This relationship between abun- dance and vigilance is explained by a simple model of starvation.

Hypobaric hypoxia at high elevation represents an important physiological stressor for montane organisms, but optimal physiological strategies to cope with hypoxia may vary among species with different life histories. Montane birds exhibit a range of migration patterns; elevational migrants breed at high elevations but winter at low elevations or migrate further south, while high-elevation residents inhabit the same elevation throughout the year. Optimal physiological strategies to cope with hypoxia might therefore differ between species that exhibit these two migratory patterns, because they differ in the amount time spent at high elevation. We examined physiological parameters associated with blood-oxygen transport (haemoglobin concentration and haematocrit, i.e. the proportion of red blood cells in blood) in nine species of elevational migrants and six species of high-elevation residents that were sampled along a 2200 m (1000–3200 m) elevational gradient. Haemoglobin concentration increased with elevation within species regardless of migratory strategy, but it was only significantly correlated with haematocrit in elevational migrants. Surprisingly, haemoglobin concentration was not correlated with haematocrit in high-elevation residents, and these species exhibited higher mean cellular haemoglobin concentration than elevational migrants. Thus, alternative physiological strategies to regulate haemoglobin concentration and blood O 2 carrying capacity appear to differ among birds with different annual elevational movement patterns.

A unique aspect of montane birds is the elevational stratification they show in their distribution, but in the Himalayas, a subset of the species show elevational migration, making bird communities on these mountains especially dynamic. Thus, understanding the elevational distribution and movement of species across seasons is important to fully understand broad-scale community patterns. In this study, we compile a comprehensive checklist of birds along a 2,300 m Hima­layan elevational gradient in the Amrutganga Valley, Kedarnath Wildlife Division, Uttarakhand, India. We recorded 244 species including 34 species new for the area and two new species for the state. Most importantly, we describe the elevational distribution of more than a 200 species and the dates of first sighting for several summer migrants in the season. We also studied changes in species richness and turnover at multiple elevations across seasons. We hope that this study provides a baseline for future research on elevational distribution of birds in the Western Himalayas.

Atmospheric deposition is the primary mechanism by which remote ecosystems are contaminated, but few data sets show how fluxes change and control soil metal burdens at the landform scale. We present mercury (Hg), lead ((210)Pb and total Pb), and cosmogenic beryllium-7 ((7)Be) measurements in organic (O) soil horizons at high-resolution elevation intervals of ∼60 m from 540 to 1160 m on Camels Hump in northern Vermont, USA. Across this gradient, average O horizon Hg ranges from 0.99 mg m(-2) in the low elevation deciduous forest zone to 7.6 mg m(-2) in the higher elevation coniferous forest at 1030 m. We measure two pronounced threshold increases in soil metal burdens above 801 and 934 m, corresponding to the two most common altitudes of cloud base, which coincide with changes in vegetation species. Lead-210, a unique tracer of tropospheric deposition, also increased from 3200 Bq m(-2) to 11500 Bq m(-2) in O horizons, exhibiting threshold responses at the same elevations as Hg and total Pb. Concentrations of (210)Pb and Hg in foliage double from 760 to 900 m elevation, indicating enhanced deposition across the transition from deciduous to coniferous forest. In contrast, (7)Be is constant across the entire elevational gradient because of its upper atmospheric source. This indicates that the effects of orographic precipitation have a smaller control on soil contaminant burdens than the coupled cloudwater deposition-vegetation scavenging effect in the presence of upwind sources. By measuring soil contaminants and unique tracers of atmospheric deposition, we show that tropospheric fluxes of Hg and Pb are higher by a factor of 2 in high-elevation coniferous forests than in adjacent lowlands. Total O horizon Hg and Pb burdens increase by over 4-fold with elevation because of the compounding effects of enhanced deposition and longer metal residence times at higher elevations (50 years).

The isolation of viable microorganisms from deep volcanic rock formations (50–450 m) within Rainier Mesa, Nevada Test Site has posed questions regarding the origin of in situ bacteria. One hypothesis under investigation is that microbial transport to depth has been facilitated via recent natural water flow from surface bacterial populations. Recoverable microbiota from surface topsail, paleosol, rock, and outflow spring water were compared to those from subsurface rock and fracture flow water to determine if relationships existed between microbial communities along an elevational gradient. Direct counts were higher than culturable counts in all samples. Top‐soil samples had higher culturable counts and numbers of nitrogen‐fixing and sulfur‐reducing bacteria than samples from the subsurface rock. Heterogeneity in microbial communities from the different samples (measured by diversity and evenness indices and by comparison of morphological and physiological tests of representative isolates) was demonstrated...

One expected response to observed global warming is an upslope shift of species elevational ranges. Here, we document changes in the elevational distributions of the small mammals within the Ruby Mountains in northeastern Nevada over an 80-year interval. We quantified range shifts by comparing distributional records from recent comprehensive field surveys (2006-2008) to earlier surveys (1927-1929) conducted at identical and nearby locations. Collector field notes from the historical surveys provided detailed trapping records and locality information, and museum specimens enabled confirmation of species' identifications. To ensure that observed shifts in range did not result from sampling bias, we employed a binomial likelihood model (introduced here) using likelihood ratios to calculate confidence intervals around observed range limits. Climate data indicate increases in both precipitation and summer maximum temperature between sampling periods. Increases in winter minimum temperatures were only evident at mid to high elevations. Consistent with predictions of change associated with climate warming, we document upslope range shifts for only two mesic-adapted species. In contrast, no xeric-adapted species expanded their ranges upslope. Rather, they showed either static distributions over time or downslope contraction or expansion. We attribute these unexpected findings to widespread land-use driven habitat change at lower elevations. Failure to account for land-use induced changes in both baseline assessments and in predicting shifts in species distributions may provide misleading objectives for conservation policies and management practices.

For trees, mammals, birds, reptiles, insects, and amphibians, the species richness on mountaintops is generally less than that of lowland areas. Coincident with this decline in species richness with increasing elevation is an increase in the altitudinal range of species. This pattern is analogous to the relationship between the latitudinal range of species and latitude (Rapoport's latitudinal rule). Both of these Rapoport phenomena, the latitudinal and the new elevational rule discussed here, can be explained as being results of differences in the breadth of climatic conditions organisms experience along the geographical gradients. The influence of latitudinal or altitudinal range size on local species richness is poorly understood, but the tendency for range margins to fall in species-rich, rather than species-poor, areas may mean that species-rich communities contain many species that are maintained only through immigration. The presence of these persistent but locally non-self-maintaining populations may explain the increased number of species found in rich communities as compared to species-poor communities without the need to invoke other differences in local species interactions.

Snags (standing dead trees) are important components of forested habitats that contribute to ecological decay and recycling processes as well as providing habitat for many life forms. As such, snags are of special interest to land managers, but information on dynamics of snag populations is lacking. We modeled trends in snag populations in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona using a Leslie matrix model developed by Raphael and Morrison (1987). Models were parameterized using data on snag abundance in five decay classes in 2002, transition rates of snags among decay classes from 1997 to 2002, and recruitment of snags into these decay classes from 1997 to 2002. Snags were sampled on randomly located, 1-ha plots (n = 52 and 58 plots in mixedconifer and ponderosa pine, respectively). These plots covered the entire elevational gradient occupied by these forest types and a wide range of stand conditions in both forest types. Trends were modeled separately for each forest type over a 30-yr time horizon. The models predicted that over this period: 1) overall snag densities would increase in both forest types, 2) densities of large snags would increase in both forest types, 3) despite these increases, densities of large snags would remain below target densities in both forest types, and 4) species composition and decay-class distributions would change only slightly in both forest types. The models described here were derived from snag data averaged over large landscapes and a wide range of stand conditions within forest types. These models thus are not suitable for modeling snag dynamics at the stand level, but rather provide a means for coarse-scale modeling of snag dynamics over large landscapes. Future inventories of snags on these plots (planned at five-year intervals) will provide a means to both test and improve model predictions.

PubMed: 19090230 Foliar mass per area (mg dm-2) -based nitrogen and phosphorus concentrations, specific leaf mass (mg dm-2) and absolute and proportional resorption in Quercus brantii was investigated along a topographic gradient from 450 to 850 m altitude. Foliar N and P concentrations in Q. brantii exhibited significant differences with respect to topographic position and sampling dates in all of the studied parameters. A sharp decrease was observed from April to September in terms of Specific Leaf Mass (SLM) values. However, mass per area-based absolute and proportional N resorption was lowest at 450 m, while absolute and proportional P resorption was lowest at 850 m. Significant correlations were found between mass per area-based leaf nutrient concentration and foliar resorption except for the correlations between absolute P resorption and foliar P concentrations at 450,650 and 750 m during full-leaf expansion and 850 m during senescence, respectively. © 2007 Asian Network for Scientific Information.

European Journal of Forest Research, 125 (1), ISSN:1612-4677, ISSN:1612-4669

International audience; Juniperus oxycedrus L. subsp. macrocarpa (Sibth. & Sm.) Ball occurs in the Mediterranean region, on the southern part of Turkey and has been widely used in landscape planning and stabilization of coastal dunes. In this study foliar N and P resorption and foliar N, P and K concentrations (on a leaf mass basis) were investigated in J. oxycedrus subsp. macrocarpa. Foliar N, P, and K concentrations and absolute and proportional N and P resorption rates along the topographic position were not changed significantly. Significant correlations were found between absolute and proportional P resorption rates and soil moisture status. However, there were no significant correlation between absolute and proportional N resorption rates and soil moisture status. Foliar N and proportional N resorption were significantly correlated although absolute N resorption was not significantly correlated with foliar N. However, foliar P was significantly correlated both absolute and proportional P resorption.; Résorption foliaire de N, P et niveaux de nutrition chez Juniperus oxycedrus L. ssp. macrocarpa (Sibth. & Sm.) Ball le long d'un gradient altitudinal.Juniperus oxycedrus L. ssp. macrocarpa (Sibth. & Sm.) se rencontre en région méditerranéenne dans le Sud de la Turquie. Il a été largement utilisé pour la stabilisation de dunes côtières et pour l'urbanisation. Dans ce travail, on a étudié chez cette espèce la résorption foliaire de N et P et les concentrations foliaires en N, P et K. Les concentrations foliaires en N, P et K et les taux de résorption (valeurs absolues et relatives) ne varient pas de façon significative avec la position topographique. Des corrélations significatives ont été trouvées entres les valeurs de résorption de P et l'humidité des sols. Cependant, il n'y a pas de corrélation significative entre les taux de résorption de N (valeurs absolues et relatives) et l'humidité des sols. La concentration foliaire en N et la résorption foliaire en N (valeurs relatives) étaient corrélées significativement bien que la résorption de N en valeurs absolues n'était pas corrélée avec la concentration foliaire en N. Pourtant les concentrations foliaires en P étaient significativement corrélées avec les résorptions de P (valeurs absolues et relatives).

The elevational gradient of species richness is often claimed to mirror the latitudinal gradient and has traditionally been explained by assuming a decrease in productivity with eleva- tion and more recently by Rapoport's rule. The influence of area on the pattern has rarely been considered. Analyses of all South American tropical land birds (more than one-fourth of the ex- tant bird species on Earth) are used to examine four species richness/elevation models: null model, Rapoport's rule, and monotonic or hump-shaped productivity/species richness relation- ships. To quantify the area effect, species-area curves were created for seven elevational zones. Not accounting for area, species richness declined monotonically with elevation, but area ac- counted for 67%-91% of the variation in species richness per zone. When area was factored out, a hump-shaped pattern emerged, with more species in the 500-1,000-m (P , .005) and 1,000- 1,500-m zones (P , .10) than in the 0-500-m zone. Rapoport's rule and the monotonic productivity/species richness relationship were thus not supported. Instead, elevational turnover rates and numbers of shared species between zones suggested that the hump-shaped pattern re- flects geometric constraints (as predicted by the null model) imposed by the narrow span of the gradient, and it is suggested that midelevational zones may represent sink habitats.

During the summers of 1993 and 1994, the Biological Resource Evaluations Team (BRET) of the Environmental Protection Group (ESH-8) conducted baseline studies within two canyon systems, Los Alamos and Guaje Canyons. Biological data was collected within each canyon to provide background and baseline information for Ecological Risk models. Baseline studies included establishment of permanent vegetation plots within each canyon along the elevational gradient. Then, in association with the various vegetation types, surveys were conducted for ground dwelling insects, birds, and small mammals. The stream channels associated with the permanent vegetation plots were characterized and aquatic macroinvertebrates collected within the stream monthly throughout a six-month period. The Geographic Position System (GPS) in combination with ARC INFO was used to map the study areas. Considerable data was collected during these surveys and are summarized in individual chapters.

The Calima River Basin is part of the Chocó Biogeográfico Ecoregion in the Pacific Coast of Colombia. Here, we compile a bat species checklist recorded for the Basin and describe the bat diversity patterns found in the mid-Calima Basin (the gradient from 300 – 1,400 m a.s.l.). The checklist comprises 55 bat species for the Basin. In the mid-Calima, 31 bat species occur (permanently or seasonally). Our results show complementary diversity patterns of bat assemblages living below and above 1,000 m. We also identified an overlap zone between 800 – 1,200 m a.s.l. where at least three pairs of sister species coexists. The sampled area is located where the Chocó and the Andes biogeographical regions are connected. The Calima River Basin has high bat richness, high variation in species composition along the elevational gradient, and harbours threatened and endemic species, highlighting its importance for conservation.

Background The impacts of climate change on phenological responses of species and communities are well-documented; however, many such studies are correlational and so less effective at assessing the causal links between changes in climate and changes in phenology. Using grasshopper communities found along an elevational gradient, we present an ideal system along the Front Range of Colorado USA that provides a mechanistic link between climate and phenology. Methodology/Principal Findings This study utilizes past (1959–1960) and present (2006–2008) surveys of grasshopper communities and daily temperature records to quantify the relationship between amount and timing of warming across years and elevations, and grasshopper timing to adulthood. Grasshopper communities were surveyed at four sites, Chautauqua Mesa (1752 m), A1 (2195 m), B1 (2591 m), and C1 (3048 m), located in prairie, lower montane, upper montane, and subalpine life zones, respectively. Changes to earlier first appearance of adults depended on the degree to which a site warmed. The lowest site showed little warming and little phenological advancement. The next highest site (A1) warmed a small, but significant, amount and grasshopper species there showed inconsistent phenological advancements. The two highest sites warmed the most, and at these sites grasshoppers showed significant phenological advancements. At these sites, late-developing species showed the greatest advancements, a pattern that correlated with an increase in rate of late-season warming. The number of growing degree days (GDDs) associated with the time to adulthood for a species was unchanged across the past and present surveys, suggesting that phenological advancement depended on when a set number of GDDs is reached during a season. Conclusions Our analyses provide clear evidence that variation in amount and timing of warming over the growing season explains the vast majority of phenological variation in this system. Our results move past simple correlation and provide a stronger process-oriented and predictive framework for understanding community level phenological responses to climate change.

There is no information in the published literature regarding Alberta’s terrestrial water-bear (Tardigrada) fauna. We surveyed across an elevational gradient (1100 – 1800 ft) on Black Cat Mountain in the Alberta Rocky Mountain range. Ten taxa were identified from 902 specimens, all of which are new records for Alberta and one species is new for Canada: Macrobiotus cf. islandicus Richters, 1904. There was no clear relationship between elevation and tardigrade distribution, possibly owing to patchiness of these animals in the field and lack of adequate replication at each elevation.

1. Sage sparrows [Amphispiza belli (Cassin)], black-throated sparrows [A. bilineata (Cassin)] and dark-eyed juncos [Junco hyemalis (L.)] winter in different habitats along an elevational gradient in the Sonoran Desert of southern California, USA. Such species replacements along environmental gradients are commonly attributed to interspecific competition. We tested the alternative hypotheses that food, predation and microhabitat structure might shape species distributions. 2. Species abundances were unrelated to food availability. Species were missing from habitats in which food standing crop was no less abundant than in the habitats they occupied. A second measure of food availability, predicted food intake rate, also failed to explain the distributions

A list oflichen species found in Glacier National Park, Montana, is presented, including notes on relative abundance, substrate, and habitat. Four hundred twenty-five species in 106 genera are reported, including 137 species previously unpublished for Montana. The diversity of Glacier National Park's lichen flora is enhanced by the wide variety of available substrates, an elevational gradient from 970 to 3,190 m, and the Park's position astride the continental divide. The lichen flora of Glacier National Park, located in northwestern Montana, is poorly known. A sys- tematic park-wide field survey has never been con- ducted. Habeck (1963) listed 22 macrolichen spe