A classification of the deciduous forest of eastern North America

Data from 300 forest stands, scattered over 29 states within the eastern North American deciduous forest, were subjected to detrended correspondence analysis (DCA) and two-way indicator species analysis (TWINSPAN) in an effort to identify classifiable units. Most species are widespread which provide a great deal of continuity in the vegetation.The deciduous forest can be divided into three forest regions: (1) northern, (2) central and (3) southern. The northern region corresponds to the hemlock-white pine-northern hardwood forest of Braun (1950). The central region includes the beech-maple and oak-hickory forests. The beech-maple as identified here includes the mixed mesophytic, beech-maple, maple-basswood and about half of the western mesophytic forests of Braun (1950). The oak-hickory includes Braun's oak-hickory, oak-chestnut and about half of the western mesophytic forests. The southern region coincides with the southern mixed hardwood forests.     

Habitat availability for bottomland hardwood forest birds: the importance of considering elevation

ABSTRACT Estimating habitat availability at large spatial scales is critical for identifying conservation and management priorities for birds. Given the effects of patch size on habitat selection and productivity of many bird species, large‐scale approaches often focus on identifying and enumerating patches large enough to support sustainable populations. Declines in the availability of bottomland hardwood forests have made this approach imperative for species that depend on these forests. However, most remaining bottomland forests are relatively low‐elevation sites that were difficult to convert to agriculture. For species that require densely vegetated understories or well‐developed litter layers, such as Swainson's Warblers (Limnothlypis swainsonii), these relatively flood‐prone forests may not provide suitable habitat and, consequently, current prioritization methods may overestimate habitat availability. We examined the effect of elevation on estimates of habitat availability for Swainson's Warblers in a 65,000‐ha bottomland hardwood forest (White River National Wildlife Refuge) in eastern Arkansas. We detected Swainson's Warblers at 88 of 2222 sampled points, and Swainson's Warblers only used relatively high elevations in the refuge. Based on our estimates, about 25% of the refuge is at a suitable elevation for Swainson's Warblers. Without considering elevation, this refuge would support an estimated 7000 to 7600 pairs, but, when elevation is considered, the estimated number of pairs drops to 1500–2000 pairs. In reality, because of a lack of suitable seral stages at high elevations in the refuge, this area likely supports only 75–100 pairs. For Swainson's Warblers and other understory‐dependent bottomland species, elevation should be incorporated into conservation planning to obtain accurate estimates of habitat availability. In addition, management should be focused on these high‐elevation areas to maximize habitat availability for these species of concern.     

Elevation‐dependent effects of forest fragmentation on plant–bird interaction networks in the tropical Andes

Tropical forests harbor diverse ecological communities of plants and animals that are organized in complex interaction networks. The diversity and structure of plant–animal interaction networks may change along elevational gradients and in response to human‐induced habitat fragmentation. While previous studies have analyzed the effects of elevation and forest fragmentation on species interaction networks in isolation, to our knowledge no study has investigated whether the effects of forest fragmentation on species interactions may differ along elevational gradients. In this study, we analyzed main and interaction effects of elevation and forest fragmentation on plant–frugivore interaction networks at plant and bird species level. Over a period spanning two years, we recorded plant–frugivore interactions at three elevations (1000, 2000 and 3000 m a.s.l.) and in two habitat types (continuous and fragmented forest) in tropical montane forests in southern Ecuador. We found a consistent effect of elevation on the structure of plant–frugivore networks. We observed a decrease in the number of effective bird partners of plants and, thus, a decline in the redundancy of bird species with increasing elevation. Furthermore, bird specialization on specific plant partners increased towards high elevations. Fragmentation had a relatively weak effect on the interaction networks for both plant and bird species, but resulted in a significant increase in bird specialization in fragmented forests at high elevations. Our results indicate that forest fragmentation may have stronger effects on plant–frugivore interaction networks at high compared to low elevations because bird species richness declined more steeply towards high elevations than plant species richness. We conclude that conservation efforts should prioritize the maintenance of consumer diversity, for instance by maintaining stretches of continuous forest. This applies in particular to species‐poor communities, such as those at high elevations, as the ecological processes in these communities seem most sensitive towards forest fragmentation.     

Dynamics and conservation of the gwangneung national forest in central Korea: A national model for forest restoration

Forests in Gwangneung National Arboretum District (GNAD) have been protected since the 15^th century. Consequently, these forests support more than 20% of all plant species in Korea. We constructed vegetation maps for landscape analysis, and forest dynamics, species diversity, and sustainable management were discussed. Secondary forests compose 51.0% of the whole vegetation, while plantations compose 45.2%.Quercus serrata dominates the forest, and the plantations are comprised mainly ofPinus koraiensis. Although dominated by plantations and human installations, the presence of a rare riparian hardwood forest, composed primarily of Q.aliena, was notable. Species diversity of the riparian (H′ = 3.38) was significantly (p<0.0001) higher than the upland (H′ = 1.56). Species turnover rate as a spatial heterogeneity was also higher. Such high species diversity and heterogeneity are justification to conserve the riparian and lowland forests in GNAD. Extensive recruitments of their own seedlings and saplings suggest a sustainable regeneration of Q.serrata and Q.aliena stands in the lower elevations, and the opposite is true for the Q.mongolica andP. rigida stands in higher elevations. GNAD contains diverse natural landscape elements that range from riparian to upland vegetation, which may well serve as a national model for forest restoration.     

Comparison of the litterfall and forest floor organic matter and nitrogen dynamics of upland forest ecosystems in north central Wisconsin

It has been suggested that a feedback exists between the vegetation and soil whereby fertile (vs infertile) sites support species with shorter leaf life spans and higher quality litter which promotes rapid decomposition and higher soil nutrient availability. The objectives of this study were to (1) characterize and compare the C and N dynamics of dominant upland forest ecosystems in north central Wisconsin, (2) compare the nutrient use efficiency (NUE) of these forests, and (3) examine the relationship between NUE and site characteristics. Analyzing data from 24 stands spanning a moisture / nutrient gradient, we found that resource-poor stands transferred less C and N from the vegetation to the forest floor, and that N remained in the forest floor at least four times longer than in more resource-rich stands. Analyzing data by leaf habit, we found that less N was transferred to the forest floor annually via litterfall in conifer stands, and that N remained in the forest floor of these stands nearly three times longer than in hardwood stands. NUE did not differ among forests with different resource availabilities, but was greater for conifers than for hardwoods. Vitousek's (1982) index of nutrient use efficiency (I_NUE1)=leaf litterfall biomass / leaf litterfall N) was most closely correlated to litterfall specific leaf area and percent hardwood leaf area index, suggesting that differences in species composition may have been responsible for the differences in NUE among our stands. NUE2, defined as ANPP / leaf litterfall N, was not closely correlated to any of the site characteristics included in this analysis.     

Influence of niche characteristics and forest type on fern species richness,abundance and plant size along an elevational gradient in Costa Rica

An analysis of the fern vegetation on 156 plots along an elevational gradient (45-3400 m) in undisturbed forests in Costa Rica, Central America, showed a hump-shaped pattern of species richness with a maximum of up to 68 species per 400 m2 at mid-elevations. This study documents the contribution of specific habitats (forest types: ridges, ravines) and niches within them (dead wood, rocks, growth zones in trees) to the local fern richness and the relation of species richness to elevation and climatic variables. Forests along ravines showed significantly higher species richness, presumably caused by high environmental humidity. The mean number of individuals of occupied niches per species increased significantly with elevation, suggesting that the niche breadth of species increased and that the differentiation of niches decreased with elevation. Both findings may explain the reduced fern species richness towards and above the upper treeline, but not at low elevations. The key factors for the decreases of species richness at the extremes of the gradient are likely to involve climatic conditions.     

Predictors of moss and liverwort species diversity of microsites in conifer‐dominated boreal forest

Patterns of moss and liverwort species diversity — species richness and species turnover (β‐diversity) — in three conifer‐dominated boreal forest stands of northern Alberta, Canada are described. We examined the relationship between bryophyte species diversity and micro‐environment at two sample grains, the microsite — substrate types for moss colonization: logs, stumps, tree bases, undisturbed patches of forest floor (dominated by feather moss species), and disturbed patches of forest floor — and the mesosite (25 m × 25 m plots). Microsite type and properties (e.g. decay class, hardwood vs softwood, pH) were the principal predictors of bryophyte species diversity and not micro‐environment variation among mesosites. Microsite type was the strongest predictor of microsite species richness and β‐diversity was higher among microsites and types and within microsites than among mesosites or stands. Microsite properties were significant predictors of species richness for all microsite types. Log and stump decay classes, influenced also by hardwood vs softwood predicted species richness of woody microsite types and soil pH and moisture predicted species richness of forest floor microsites. β‐diversity was highest for tree bases and disturbed patches of forest floor and lowest for logs. Mesosite β‐diversity was lower than that among microsites, and mesosite species richness was not well explained by measured environmental parameters. Results suggest that in conifer‐dominated boreal stands, species richness of microsites is only negligibly influenced by within‐stand variation at the mesosite grain and that substrate characteristics are the most important predictors of bryophyte species diversity in this ecosystem.     

Tree growth response to drought and temperature in a mountain landscape in northern Arizona, USA

Aim To understand how tree growth response to regional drought and temperature varies between tree species, elevations and forest types in a mountain landscape. Location Twenty‐one sites on an elevation gradient of 1500 m on the San Francisco Peaks, northern Arizona, USA. Methods Tree‐ring data for the years 1950–2000 for eight tree species (Abies lasiocarpa var. arizonica (Merriam) Lemm., Picea engelmannii Parry ex Engelm., Pinus aristata Engelm., Pinus edulis Engelm., Pinus flexilis James, Pinus ponderosa Dougl. ex Laws., Pseudotsuga menziesii var. glauca (Beissn.) Franco and Quercus gambelii Nutt.) were used to compare sensitivity of radial growth to regional drought and temperature among co‐occurring species at the same site, and between sites that differed in elevation and species composition. Results For Picea engelmannii, Pinus flexilis, Pinus ponderosa and Pseudotsuga menziesii, trees in drier, low‐elevation stands generally had greater sensitivity of radial growth to regional drought than trees of the same species in wetter, high‐elevation stands. Species low in their elevational range had greater drought sensitivity than co‐occurring species high in their elevational range at the pinyon‐juniper/ponderosa pine forest ecotone, ponderosa pine/mixed conifer forest ecotone and high‐elevation invaded meadows, but not at the mixed conifer/subalpine forest ecotone. Sensitivity of radial growth to regional drought was greater at drier, low‐elevation compared with wetter, high‐elevation forests. Yearly growth was positively correlated with measures of regional water availability at all sites, except high‐elevation invaded meadows where growth was weakly correlated with all climatic factors. Yearly growth in high‐elevation forests up to 3300 m a.s.l. was more strongly correlated with water availability than temperature. Main conclusions Severe regional drought reduced growth of all dominant tree species over a gradient of precipitation and temperature represented by a 1500‐m change in elevation, but response to drought varied between species and stands. Growth was reduced the most in drier, low‐elevation forests and in species growing low in their elevational range in ecotones, and the least for trees that had recently invaded high‐elevation meadows. Constraints on tree growth from drought and high temperature are important for high‐elevation subalpine forests located near the southern‐most range of the dominant species.     

Vegetation of a coastal sand dune system in southern New Zealand

The introduction of vigorous exotic species has destroyed much of the native sand dune vegetation along the coasts of South Island, New Zealand. However, some dunes built by the native cyperad Desmoschoenus spiralis still remain in the southwest. The dunes at Cole Creek, on the West coast of South Island, were chosen as a relatively pristine study area. 15 transects were laid through semi-fixed dunes into dwarf forest. Environmental measurements were taken at regular intervals through the dunes: pH, soil moisture, organic matter, conductivity, nutrient status and elevation. Classification and ordination of these data demonstrated that two major environmental areas were present - open dune and dwarf forest - with an abrupt ecotone between them. Vegetation analyses revealed a loosely-banded pattern, parallel to the sea. Vegetation types with few but constant species such as Desmoschoenus spiralis and Calystegia soldanella, predominated in the open dune. Forest species were rarely found seaward of the dune/forest boundary, though there was evidence the Spatial Mass Effect was operating. Multiple regression and canonical correlation of the vegetation and environmental factors showed that the main factors affecting vegetation patterns were the environmental complex related to distance from the sea, elevation above mean tide, soil alkalinity and moisture.     

Bryophyte Species Diversity in Secondary Forests Dominated by the Introduced Species Spathodea campanulata Beauv. in Puerto Rico

The introduced tree species Spathodea campanulata (Bignoniaceae) forms novel forests in Puerto Rico, these having emerged after the abandonment of fields in the mid‐20th century and resulting in forests with a new species composition. We assessed bryophyte species richness in these novel forests and sought correlations with geological substrate, past land use, forest edge and patch area, forest structure, elevation, microhabitat diversity, tree species richness, and microclimatic conditions. Transects were established (edge and forest interior) in nine moist forest patches dominated by Spathodea in north‐central Puerto Rico. These Spathodea forest patches ranged from 0.6 to 9 ha. ANOVA, Chi‐square, correlation, and cluster analyses were used in data analyses. We found 57 bryophyte species. There was a significant difference in bryophyte richness among patches. Those on karst exhibited highest bryophyte richness due to microhabitat diversity, past land use, and shorter hydroperiods. Alluvial sites scored lowest in bryophyte species richness, and forest structure was important for bryophyte communities on these sites. Significant differences in temperature, relative humidity, and light intensity were observed between edge and forest interior. These appeared important for establishing bryophyte species cover but not richness and composition. Microhabitat diversity, patch area, and forest age were more related to bryophyte species richness than elevation, exposed edge, and tree species richness, regardless of geologic substrate. Collectively, Spathodea patches were similar to mature forests on the Island with respect to bryophyte species richness and composition. Novel Spathodea forests have conservation value due to their habitat suitability for bryophyte communities.     

Spatial distribution and temporal dynamics of high‐elevation forest stands in southern Siberia

Aim To evaluate the hypothesis that topographic features of high‐elevation mountain environments govern spatial distribution and climate‐driven dynamics of the forest. Location Upper mountain forest stands (elevation range 1800–2600 m) in the mountains of southern Siberia. Methods Archive maps, satellite and on‐ground data from1960 to 2002 were used. Data were normalized to avoid bias caused by uneven distribution of topographic features (elevation, azimuth and slope steepness) within the analysed area. Spatial distribution of forest stands was analysed with respect to topography based on a digital elevation model (DEM). Results Spatial patterns in mountain forests are anisotropic with respect to azimuth, slope steepness and elevation. At a given elevation, the majority of forests occupied slopes with greater than mean slope values. As the elevation increased, forests shifted to steeper slopes. The orientation of forest azimuth distribution changed clockwise with increase in elevation (the total shift was 120°), indicating a combined effect of wind and water stress on the observed forest patterns. Warming caused changes in the forest distribution patterns during the last four decades. The area of closed forests increased 1.5 times, which was attributed to increased stand density and tree migration. The migration rate was 1.5 ± 0.9 m year^–1, causing a mean forest line shift of 63 ± 37 m. Along with upward migration, downward tree migration onto hill slopes was observed. Changes in tree morphology were also noted as widespread transformation of the prostrate forms of Siberian pine and larch into erect forms. Main conclusions The spatial pattern of upper mountain forests as well as the response of forests to warming strongly depends on topographic relief features (elevation, azimuth and slope steepness). With elevation increase (and thus a harsher environment) forests shifted to steep wind‐protected slopes. A considerable increase in the stand area and increased elevation of the upper forest line was observed coincident with the climate warming that was observed. Warming promotes migration of trees to areas that are less protected from winter desiccation and snow abrasion (i.e. areas with lower values of slope steepness). Climate‐induced forest response has significantly modified the spatial patterns of high‐elevation forests in southern Siberia during the last four decades, as well as tree morphology.     

Effects of Wildlife Forestry on Abundance of Breeding Birds in Bottomland Hardwood Forests of Louisiana

ABSTRACT Effects of silvicultural activities on birds are of increasing interest because of documented national declines in breeding bird populations for some species and the potential that these declines are in part due to changes in forest habitat. Silviculturally induced disturbances have been advocated as a means to achieve suitable forest conditions for priority wildlife species in bottomland hardwood forests. We evaluated how silvicultural activities on conservation lands in bottomland hardwood forests of Louisiana, USA, influenced species-specific densities of breeding birds. Our data were from independent studies, which used standardized point-count surveys for breeding birds in 124 bottomland hardwood forest stands on 12 management areas. We used Program DISTANCE 5.0, Release 2.0 (Thomas et al. 2006) to estimate density for 43 species with >50 detections. For 36 of those species we compared density estimates among harvest regimes (individual selection, group selection, extensive harvest, and no harvest). We observed 10 species with similar densities in those harvest regimes compared with densities in stands not harvested. However, we observed 10 species that were negatively impacted by harvest with greater densities in stands not harvested, 9 species with greater densities in individual selection stands, 4 species with greater densities in group selection stands, and 4 species with greater densities in stands receiving an extensive harvest (e.g., >40% canopy removal). Differences in intensity of harvest influenced densities of breeding birds. Moreover, community-wide avian conservation values of stands subjected to individual and group selection, and stands not harvested, were similar to each other and greater than that of stands subjected to extensive harvest that removed >40% canopy cover. These results have implications for managers estimating breeding bird populations, in addition to predicting changes in bird communities as a result of prescribed and future forest management practices.     

Floristic diversity along altitudinal gradient under Betula utilis in North Western Himalayas of Kashmir,India

A study on community structure was carried out along three altitudinal gradients viz., Lower (3000–3200m), Middle (3200–3400m) and upper (3400–3600m) asl in Sindh Forest Division (Sonamarg) and Tangmarg Forest Divisions (Gulmarg) in sub alpine zone of North Western Kashmir Himalayas, India. The floristic structure revealed that Betula stands at Sonamarg forests supported 48 species belonging to 26 families on South Eastern aspect and 53 species belonging to 28 families on South Western aspect, whereas Gulmarg forest was represented by 54 species of 28 families. The overall community structure of Betula stands depicted that Asteraceae, Poaceae, Rosaceae and Lamiaceae were the dominant families in these timberline forests. The dispersion showed that 65.48% species were contagiously distributed, 25.67 and 8.85% species showed random and regular distribution. Betula utilis shared the top niche with the dominance of 61.56 and 76.27% on SE and SW aspect at Sonamarg, and 71.81% at Gulmarg. Species richness decreased with elevation and species diversity of the forest was relatively low, the decrease in these parameter with increasing altitude can be directly related to high grazing pressure, harsh climatic conditions, topography and snow, which covers these areas for longer times especially during the growing season.     

Coarse woody debris in Australian forest ecosystems: A review

Abstract Coarse woody debris (CWD) is the standing and fallen dead wood in a forest and serves an important role in ecosystem functioning. There have been several studies that include estimates of CWD in Australian forests but little synthesis of these results. This paper presents findings from a literature review of CWD and fine litter quantities. Estimates of forest‐floor CWD, snags and litter from the literature are presented for woodland, rainforest, open forest and tall open forest, pine plantation and native hardwood plantation. Mean mass of forest floor CWD in Australian native forests ranged from 19 t ha^?1 in woodland to 134 t ha^?1 in tall open forest. These values were generally within the range of those observed for similar ecosystems in other parts of the world. Quantities in tall open forests were found to be considerably higher than those observed for hardwood forests in North America, and more similar to the amounts reported for coniferous forests with large sized trees on the west coast of the USA and Canada. Mean proportion of total above‐ground biomass as forest floor CWD was approximately 18% in open forests, 16% in tall open forests, 13% in rainforests, and 4% in eucalypt plantations. CWD can be high in exotic pine plantations when there are considerable quantities of residue from previous native forest stands. Mean snag biomass in Australian forests was generally lower than the US mean for snags in conifer forests and higher than hardwood forest. These results are of value for studies of carbon and nutrient stocks and dynamics, habitat values and fire hazards.     

Impacts of Hemlock Loss on Nitrogen Retention Vary with Soil Nitrogen Availability in the Southern Appalachian Mountains

The impacts of exotic insects and pathogens on forest ecosystems are increasingly recognized, yet the factors influencing the magnitude of effects remain poorly understood. Eastern hemlock (Tsuga canadensis) exerts strong control on nitrogen (N) dynamics, and its loss due to infestation by the hemlock woolly adelgid (Adelges tsugae) is expected to decrease N retention in impacted stands. We evaluated the potential for site variation in N availability to influence the magnitude of effects of hemlock decline on N dynamics in mixed hardwood stands. We measured N pools and fluxes at three elevations (low, mid, high) subjected to increasing atmospheric N deposition where hemlock was declining or absent (as reference), in western North Carolina. Nitrogen pools and fluxes varied substantially with elevation and increasing N availability. Total forest floor and mineral soil N increased (P?<?0.0001, P?=?0.0017, resp.) and forest floor and soil carbon (C) to N ratio decreased with elevation (P?<?0.0001, P?=?0.0123, resp.), suggesting that these high elevation pools are accumulating available N. Contrary to expectations, subsurface leaching of inorganic N was minimal overall (<1?kg?ha^?1 9 months^?1), and was not higher in stands with hemlock mortality. Mean subsurface flux was 0.16?±?0.04 (SE) (kg?N?ha^?1 100?days^?1) in reference and 0.17?±?0.05 (kg?N?ha^?1 100?days^?1) in declining hemlock stands. Moreover, although subsurface N flux increased with N availability in reference stands, there was no relationship between N availability and flux in stands experiencing hemlock decline. Higher foliar N and observed increases in the growth of hardwood species in high elevation stands suggest that hemlock decline has stimulated N uptake and growth by healthy vegetation within this mixed forest, and may contribute to decoupling the relationship between N deposition and ecosystem N flux.     

Estimating Fine Root Turnover in Tropical Forests along an Elevational Transect using Minirhizotrons

Growth and death of fine roots represent an important carbon sink in forests. Our understanding of the patterns of fine root turnover is limited, in particular in tropical forests, despite its acknowledged importance in the global carbon cycle. We used the minirhizotron technique for studying the changes in fine root longevity and turnover along a 2000-m-elevational transect in the tropical mountain forests of South Ecuador. Fine root growth and loss rates were monitored during a 5-mo period at intervals of four weeks with each 10 minirhizotron tubes in three stands at 1050, 1890, and 3060 m asl. Average root loss rate decreased from 1.07 to 0.72 g/g/yr from 1050 to 1890 m, indicating an increase in mean root longevity with increasing elevation. However average root loss rate increased again toward the uppermost stand at 3060 m (1.30 g/g/yr). Thus, root longevity increased from lower montane to mid-montane elevation as would be expected from an effect of low temperature on root turnover, but it decreased further upslope despite colder temperatures. We suggest that adverse soil conditions may reduce root longevity at high elevations in South Ecuador, and are thus additional factors besides temperature that control root dynamics in tropical mountain forests.     

Species–soil associations, disturbance, and nutrient cycling in an Australian tropical rainforest

Resource availability and disturbance are important factors that shape the composition, structure, and functioning of ecosystems. We investigated the effects of soil fertility and disturbance on plant–soil interactions and nutrient cycling in a diverse tropical rainforest. Our goal was to determine how common soil specialisation is among species and how plant–soil interactions affect ecosystem functioning in the presence of disturbance. Most species (59%) showed significant fidelity to either fertile (basalt) or infertile (schist) soils. Obligate schist specialists (six species) contributed 39 and 37% to total stand-level basal area and aboveground net primary productivity, respectively. High nutrient use efficiency of schist specialists reduced the rates of within-stand nutrient cycling through the production of nutrient-poor plant tissues and litter. Although forests on schist soils had higher basal area and similar rates of productivity to forests on basalt, uptake of Mg, K, P, and N were markedly less on schist than on basalt, particularly after a cyclone disturbance. Stands on schist soils were also less affected by the cyclone and, as a result, contributed less (ca. 50%) Mg, K, P, and N inputs to the forest floor (via litterfall) than stands on basalt soils. System “openness” (i.e. the risk of nutrient loss) from cyclone-affected basalt forests was minimised by high rates of uptake following disturbance and large effective cation exchange capacities of soils. Soil–plant-disturbance interactions are likely to engender different fitness-enhancing strategies on fertile and infertile soils, possibly leading to the development and/or maintenance of diversity in rainforests.     

Forest aboveground biomass along an elevational transect in Sulawesi,Indonesia, and the role of Fagaceae in tropical montane rain forests

Aim This study investigates how estimated tree aboveground biomass (AGB) of tropical montane rain forests varies with elevation, and how this variation is related to elevational change in floristic composition, phylogenetic community structure and the biogeography of the dominant tree taxa. Location Lore Lindu National Park, Sulawesi, Indonesia. Methods Floristic inventories and stand structural analyses were conducted on 13 plots (each 0.24 ha) in four old‐growth forest stands at 1050, 1400, 1800 and 2400 m a.s.l. (submontane to upper montane elevations). Tree AGB estimates were based on d.b.h., height and wood specific gravity. Phylogenetic diversity and biogeographical patterns were analysed based on tree family composition weighted by AGB. Elevational trends in AGB were compared with other Southeast Asian and Neotropical transect studies (n = 7). Results AGB was invariant from sub‐ to mid‐montane elevation (309–301 Mg ha^?1) and increased slightly to 323 Mg ha^?1 at upper montane elevation. While tree and canopy height decreased, wood specific gravity increased. Magnoliids accounted for most of the AGB at submontane elevations, while eurosids I (including Fagaceae) contributed substantially to AGB at all elevations. Phylogenetic diversity was highest at upper montane elevations, with co‐dominance of tree ferns, Podocarpaceae, Trimeniaceae and asterids/euasterids II, and was lowest at lower/mid‐montane elevations, where Fagaceae contributed > 50% of AGB. Biogeographical patterns showed a progression from dominant tropical families at submontane to tropical Fagaceae (Castanopsis, Lithocarpus) at lower/mid‐montane, and to conifers and Australasian endemics at upper montane elevations. Cross‐continental comparisons revealed an elevational AGB decrease in transects with low/no presence of Fagaceae, but relatively high AGB in montane forests with moderate to high abundance of this family. Main conclusions AGB is determined by both changes in forest structure and shifts in species composition. In our study, these two factors traded off so that there was no net change in AGB, even though there were large changes in forest structure and composition along the elevational gradient. Southeast Asian montane rain forests dominated by Fagaceae constitute important carbon stocks. The importance of biogeography and species traits for biomass estimation should be considered by initiatives to reduce emissions from deforestation and forest degradation (REDD) and in taxon choice in reforestation for carbon offsetting.     

Dispersal spectra,diaspore size and the importance of endozoochory in the equatorial Andean montane forests

The dispersal syndrome hypothesis states that plant diaspores show morphological features that are the results of adaptation for dispersal by a particular vector. This can enable to identify the relative importance of dispersal agents within plant communities. Nevertheless, there is still little information about seed dispersal spectra and diaspore traits related to different dispersal agents in the equatorial montane forests, despite their high biodiversity and important ecosystem services as watersheds for human communities. Due to an increase in environmental stress at high elevations a reduction in the prevalence of endozoochory, and a reduction in the size of endozoochorous diaspores in plant assemblages could be expected. We reviewed published data from 64 Andean cloud forest plots to assess the dispersal spectra, the incidence of different traits related to seed dispersal, and the distribution of dispersal syndromes within cloud forests of northern South America. We then evaluated two questions related to seed dispersal in these forests: (1) Does the number and percentage of endozoochorous species in woody plant assemblages decrease at higher elevation? and (2) Does the mean diaspore size of endozoochorously dispersed tree assemblages decrease with elevation?     

Alien dominance of the parasitoid wasp community along an elevation gradient on Hawai’i Island

Through intentional and accidental introduction, more than 100 species of alien Ichneumonidae and Braconidae (Hymenoptera) have become established in the Hawaiian Islands. The extent to which these parasitoid wasps have penetrated native wet forests was investigated over a 1,765 m elevation gradient on windward Hawai’i Island. For >1 year, malaise traps were used to continuously monitor parasitoid abundance and species richness in nine sites over three elevations. A total of 18,996 individuals from 16 subfamilies were collected. Overall, the fauna was dominated by aliens, with 44 of 58 species foreign to the Hawaiian Islands. Ichneumonidae was dominant over Braconidae in terms of both diversity and abundance, comprising 67.5% of individuals and 69.0% of species collected. Parasitoid abundance and species richness varied significantly with elevation: abundance was greater at mid and high elevations compared to low elevation while species richness increased with increasing elevation, with all three elevations differing significantly from each other. Nine species purposely introduced to control pest insects were found, but one braconid, Meteorus laphygmae, comprised 98.0% of this assemblage, or 28.3% of the entire fauna. Endemic species, primarily within the genera Spolas and Enicospilus, were collected almost exclusively at mid- and high-elevation sites, where they made up 22.1% and 36.0% of the total catch, respectively. Overall, 75.9% of species and 96.0% of individuals are inferred to parasitize Lepidoptera larvae and pupae. Our results support previous data indicating that alien parasitoids have deeply penetrated native forest habitats and may have substantial impacts on Hawaiian ecosystems.