Bamboo Cover Research Articles

Distribution and habitat attributes associated with the Himalayan red panda in the westernmost distribution range.

The Himalayan red panda (Ailurus fulgens), a recently confirmed distinct species in the red panda genus, is distributed in Nepal, India, Bhutan, and south Tibet. Nepal represents the westernmost distribution of the Himalayan red panda. This study aims to determine important habitat features influencing the distribution of red panda and recommend possible habitat corridors. This manuscript described current potential habitat of 3,222 km2 with the relative abundance of 3.34 signs/km in Nepal. Aspect, canopy cover, bamboo cover, and distance to water were the important habitat attributes. It suggested five potential corridors in western Nepal. Overall, the study has important implications for conservation of the Himalayan red panda in western distribution range.

Effects of selective logging, fragmentation, and dominance of bamboos on the structure and diversity of Araucaria Forest fragments

During the colonisation of the South of Brazil, logging of tree species with high economic value was one of the main economic activities. In this process, almost all Araucaria Forest, one of the forest types of the Atlantic Forest that once covered most of this region, was severely fragmented and disturbed. One of the consequences of this disturbance was the population growth of a native bamboo species (Merostachys skvortzovii) that came out of the small patches where it occurred naturally, to dominate the understory of forest fragments. In this study, we evaluated if the fragment size, forest-edge effect, and abundance of bamboos affect forest structure and functional guilds in a region of Araucaria Forest in Parana state, Brazil. We sampled trees (DBH ≥ 4.8 cm) in five fragments (24–270 ha) in two plots (2000 m2 each) located at the edge and centre of each one. We analysed the forest structure (species composition and species richness, abundance, and basal area) and estimated the bamboo cover in each plot. We recorded 1743 individuals of 68 tree species in the five analysed patches. The fragments were very similar in floristic composition and structure (species richness, abundance, basal area). The bamboo cover was the main factor affecting forest structure and species guilds distribution, followed by distance from the fragment edge. These results show a simplification of floristic, structural, and functional attributes of Araucaria Forest remnants suggesting that the selective logging followed by fragmentation and native bamboo overabundance are important factors in the imporishment of this endangered biome.

Towards nationwide mapping of bamboo resources in the Philippines: testing the pixel-based and fractional cover approaches

ABSTRACT In tropical and subtropical countries, the awareness on the importance of bamboos to the environment and economy is increasing and so is the demand for spatial bamboo information. However, mapping bamboos especially those naturally grown has been challenging, as these grasses are often mixed with other land-use and land-cover (LULC). In this study, we used Sentinel 1 and Sentinel 2 remote sensing (RS) images, and their vegetation indices to accurately map the bamboos of Iloilo province in the Philippines using: (1) pixel-based method that mapped bamboos and other LULC at 10 m resolution, and (2) fractional cover method that mapped bamboo cover at 100 m resolution (% ha−1). A random forest model was trained for each method and then validated per hectare basis using a 50:50 training-validation ratio of a stratified random sample. The fractional cover method showed 0.34 higher Nash-Sutcliffe Efficiency (NSE) and 5.10% lower Root Mean Square Error (RMSE) than the pixel-based method. Further validation within upland and lowland sites also favoured the fractional cover method, but the results of the two methods were closer in the upland site (bamboo plantation). Errors at 10 m resolution especially in the lowlands were mostly commission errors, likely because of the spectral similarity and proximity between bamboos and > 14 vegetations. Averaging the RS inputs into 100 m resulted in at most 12% separation of reflectance values among bamboos, forests, and other vegetations. Using the bamboo cover map, a total of 14,795 (± 1,283) ha bamboos and 7.45 (± 4.20) million harvestable culms (poles) were estimated for the whole province, where 54% come from the lowland. We suggest using the fractional cover method for nationwide baselining of bamboo resources.

Utilization of semi-aerobic bamboo lid to decrease organic matter

Catfish cultivation will produce wastewater with a high content of organic matter from feces and uneaten feed. If the wastewater is discharged directly into common waters, it will disturb the aquatic ecosystem. So, it is necessary to treat wastewater before it is discharged into common waters. The purpose of this study is to determine the difference in the percentage of experimental media using wiker bamboo lid towards the organic matter in the wastewater of catfish farming. The research was conducted from September to October 2019 at the Laboratorium Hidrobiologi Divisi Sumberdaya Ikan, Universitas Brawijaya. The research method used was an experimental method with a 2-factor factorial completely randomized design. The first factor was the percentage of bamboo wicker lid (25%, 50%, 75%, 100% and 0% (control)). The second factor was the observation time (12, 36, 48, 60 and 72 hour). The results indicated that organic matter could decrease to 82.19% (73.31 mg / L to 13.06 mg / L) in the 75% lid treatment at 48 hours. The results of water quality measurements except carbondioxide are in accordance with water quality standards. The presence of bamboo cover can reduce organic matter in wastewater. However, it needs treatment for carbondioxide.

Soil properties and bamboo cover drive the structure of the woody plant community along a forest–savanna gradient

AbstractUnderstanding the role of environmental conditions and geographic space on species distributions is a major goal of ecological studies. Here, we investigate the effects of soil properties, a native bamboo (Actinocladum verticillatum (Nees) McClure ex Soderstr) ground cover and geographic distance on species richness and turnover in the Brazilian Cerrado. We established three transects along a forest–savanna gradient (14°41′S and 52°20′W), from the lowland next to a stream to the top of a hill, where we sampled the woody plant community (DBH ≥ 3 cm), soil properties and ground cover of A. verticillatum. We evaluated changes in species composition with a principal coordinates analysis, and the effects of the environmental predictors on species richness using generalised linear models and on species turnover using generalised dissimilarity modelling. We found that species richness increases with K concentration in the soil and decreases with Zn concentration in the soil and bamboo cover. The predictors explained 62% of species turnover, with environmental parameters (soil properties, bamboo cover and altitude) having the most significant contribution (80%), followed by the spatially structured environmental variation (20%). The most important environmental predictors of woody species turnover were soil concentration of Zn, P and K, altitude, and bamboo cover. Changes in species richness and composition in the studied gradient were strongly associated with plot height, bamboo cover and soil content of K, Zn and P. Our findings indicate that nutrient availability and competition with bamboo explain vegetation structure and composition in this region.

Landscape variables affecting the Himalayan red panda Ailurus fulgens occupancy in wet season along the mountains in Nepal.

The Himalayan red panda is an endangered mammal endemic to Eastern Himalayan and South Western China. Data deficiency often hinders understanding of their spatial distribution and habitat use, which is critical for species conservation planning. We used sign surveys covering the entire potential red panda habitat over 22,453 km2 along the mid-hills and high mountains encompassing six conservation complexes in Nepal. To estimate red panda distribution using an occupancy framework, we walked 1,451 km along 446 sampled grid cells out of 4,631 grid cells in the wet season of 2016. We used single-species, single-season models to make inferences regarding covariates influencing detection and occupancy. We estimated the probability of detection and occupancy based on model-averaging techniques and drew predictive maps showing site-specific occupancy estimates. We observed red panda in 213 grid cells and found covariates such as elevation, distance to water sources, and bamboo cover influencing the occupancy. Red panda detection probability estimated at 0.70 (0.02). We estimated red panda site occupancy (sampled grid cells) and landscape occupancy (across the potential habitat) at 0.48 (0.01) and 0.40 (0.02) respectively. The predictive map shows a site-specific variation in the spatial distribution of this arboreal species along the priority red panda conservation complexes. Data on their spatial distribution may serve as a baseline for future studies and are expected to aid in species conservation planning in priority conservation complexes.

Coupled effects of climatic forcing and the human footprint on wildlife movement and space use in a dynamic floodplain landscape

With climate change, terrestrial fauna in riparian floodplain ecosystems must adapt to a predicted increase in frequency and magnitude of fluvial perturbations. Seasonal migration to seek refuge from floodwaters represents a central adaptation strategy, but may entail risky navigation of anthropogenic spaces in heterogeneous landscapes. Here, we demonstrate the opportunities and constraints large-bodied mammalian herbivores face during an adaptive response of obligatory flood-driven refuge migration, across a human-dominated environment. Our study system, centred around a productive protected area––Kaziranga National Park in Assam, Northeast India––on the floodplains of the Brahmaputra River, is home to an abundance of large herbivores that undertake seasonal migrations in response to floods. We contrast species distribution data during a major flood event with those from the dry season to illustrate season-specific movement and space use decisions of large herbivores ranging in body mass from the 3000-kg Asian elephant Elephas maximus to the 20-kg muntjac Muntiacus muntjak. In the dry season, most large herbivores––a majority of which are endangered and threatened by anthropogenic pressures––avoided areas with a strong human footprint, while preferring spaces with high land-use diversity. During the floods, such species were pushed out of inundated habitats within the protected area, and they chose to move through woodlands and areas under bamboo cover on private lands, as they migrated to forested refugia on higher ground. Our results show how seasonal environmental constraints shaped by floods determine the internal motivation of animals to risk traversing a human-dominated space to seek refuge, which contextually defines how animals view and navigate the landscape. Such insights underscore the importance of dynamic and adaptive planning, and participatory conservation efforts, to facilitate connectivity in the changing environment and climate of the present Anthropocene.

Experimental study on double-headed screw joints and their application in bamboo shear walls

Due to the weak withdrawal capacities of conventional nail joints, using double-headed screw joints as reliable connections in bamboo structures is investigated for the first time. A two-step test program is presented in this paper. In the first step, a double shear test is carried out to investigate the influences of the end distance and bamboo grain direction on the performance of double-headed screw joints. The test shows that there are four main failure modes of double-headed screw joints: double-headed screw shear failure, bearing failure of the hole wall, tensile failure of the bamboo cover panel and shear failure of the cover panel end. In the second step of test, the proposed double-headed screw joints are applied to three single-layer single-span bamboo shear walls, and low-cycle reversed loading tests are applied to the walls with double-headed screw spacings of 50 mm, 100 mm and 150 mm. The failure mode, hysteretic behaviour and energy dissipation performance of the shear walls are discussed. Test results show that the two main failure modes of the bamboo shear walls are the tensile failure of the edge of the wall and shear failure of the double-headed screws. Among the different spacings, the bearing capacity and effective stiffness of the wall with a double-headed screw spacing of 50 mm are the largest, the ductility and energy dissipation capacity of the bamboo shear wall with a double-headed screw spacing of 100 mm are the largest, and the bearing capacity and ductility of the bamboo shear wall with a double-headed screw spacing of 150 mm are the worst.

Genetic diversity, population structure, and gene flow analysis of lowland bamboo [Oxytenanthera abyssinica (A. Rich.) Munro] in Ethiopia.

Bamboo, a member of subfamily Bambusoideae in the grass family (Poaceae), is one of the most important nontimber forest resources and a potential alternative to wood and wood products. Ethiopian lowland bamboo (Oxytenanthera abyssinica) is an economically and ecologically important species which accounts about 85% of total bamboo coverage in the country. This species is experiencing population decline due to a number of anthropogenic factors. As a foundation step, genetic diversity, population structure, and gene flow analysis of various O. abyssinica populations found in Ethiopia are studied using inter‐simple sequence repeat markers. One hundred and thirty isolates of bamboo belonging to 13 geographically diverse populations were collected for DNA extraction and analysis. Heterozygosity, level of polymorphism, marker efficiency, Nei's gene diversity (H), and Shannon's information index (I) analysis, analysis of molecular variance (AMOVA), analysis for cluster, principal coordinates (PCoA), and admixture analyses were performed based on the markers banding pattern. The results indicated high genetic variation (84.48%) at species level. The H, I, observed and effective number of alleles at the species level were 0.2702, 0.4061, 1.8448, and 1.4744, respectively, suggesting a relatively high level of genetic diversity. However, genetic differentiation at the population level was relatively low. Using grouped populations, AMOVA revealed that most (61.05%) of the diversity was distributed within the populations with F ST = 0.38949, F SC = 0.10486, and F CT = 0.31797. Cluster analysis grouped the populations into markedly distinct clusters, suggesting confined propagation in distinct geographic regions. STRUCTURE analyses showed K = 2 for all populations and K = 11 excluding Gambella population. Using these markers, we found strong evidence that the genetic diversity of the lowland bamboo is associated with distinct geographic regions and that isolates of Gambella Region, with their unique genetic origin, are quite different from other bamboos found in the country.

Determinants of ecosystem stability in a diverse temperate forest

Understanding how diversity affects ecosystem stability is crucial for predicting the consequences of continued habitat and biodiversity loss on ecosystem functions and services. Long‐term productivity stability in plant communities is often associated with greater species, phylogenetic or functional diversity, more complex size and age structures, or higher asynchrony in species fluctuations (compensatory dynamics), all potentially increasing community resistance to perturbations. However, the relative importance of these stabilizing pathways is still poorly understood, especially in old‐growth species‐rich forests. Here we explore how compensatory dynamics and multiple facets of diversity underpin temporal stability of wood biomass production over forty years in a Japanese temperate forest, based on more than 45 500 stem increments from 15 species. Whereas the effect of species richness and phylogenetic diversity was small, the old‐growth structural attributes markedly increased community stability via increased asynchrony in the performance of co‐occurring species. Greater standing tree volume, stem density and interspecific variation in growth rates enhanced productivity stability both directly and indirectly via increased asynchrony. This corroborates the predictions of increased compensatory dynamics with increased asymmetric competition for light in a more productive environment. Asymmetric competition in old‐growth patches, between dominant oaks and sub‐canopy shade‐tolerant firs and maples, is a major driver of productivity stability over time via compensatory dynamics. Overall productivity remains relatively constant in old‐growth patches, as abundant firs and maples in the lower canopy layers compensate for biomass losses in canopy oaks caused by aging, wind and snow disturbances. Younger forest patches, composed of fast‐growing, shade‐intolerant species, had a lower stability of productivity, with reduced stem basal area and tree density due to higher understory bamboo coverage preventing tree regeneration and growth. We provide new insights into mechanisms underlying the stability of ecosystem functioning in diverse forest ecosystems, and emphasize the importance of preserving and supporting old‐growth forests and their structural complexity.

The endangered red panda in Himalayas: Potential distribution and ecological habitat associates

The red panda Ailurus fulgens, an endangered herbivorous member of the order Carnivora that is endemic to the eastern Himalayan broadleaf and coniferous forests, is surviving under threats induced by human activity and climate change. The distribution range of the red panda in Nepal represents an understudied remnant population at the edge of its western biogeographic distribution range. To build a potentially suitable habitat, we used red panda occurrence and the least correlated bioclimatic variables in MaxEnt modeling. In addition, habitat variables were recorded in transects and quadrat plots to identify ecologically important variables for the red panda habitat. Currently, 14.23% (21,680 km2) of Nepal is a climatically suitable habitat for the red panda. The mean temperature of the warmest quarter, annual temperature range, mean temperature of the coldest quarter and precipitation of the coldest quarter are the major contributing variables in the model, with an area under the ROC curve (AUC) of 0.94. Climatic, geographic, and habitat group variables have considerable contributions, while disturbance has a low contribution. Multiple factor analysis identified mixed broadleaf forest, East Himalayan oak-laurel forest, canopy cover >20%, ground substrate use, bamboo cover >20%, tree stump presence, fallen logs of small trees and habitat without grazing as having high contributions in the qualitative groups. Similarly, the elevation, distance from settlements and roads, distance to water sources, annual temperature range, mean diurnal range and annual precipitation were important variables in the quantitative groups. The results will help guide conservation managers in implementing effective habitat management programs for the red panda.

Home range, population density, and foraging behaviour of the Yellow-breasted Warbling-Antbird (Hypocnemis subflava) in forest fragments in southwestern Brazilian Amazonia

ABSTRACTHypocnemis subflava is endemic to southwestern Amazonia, where it prefers habitats dominated by bamboo. We estimated the home range size and population density of this species, and described its foraging behaviour and occurrence in bamboo. We collected data within 1 – ha plots located in three different 16-ha grids. The mean home range of the species was 0.65 ± 0.26 ha (mean ± SE). The population density was 0.44–0.75 individuals per hectare and 0.22–0.37 pairs per hectare within the different study plots. The birds foraged primarily in bamboo leaves (65%), using ‘reach’ and ‘sally’ movements, and foraging was most frequent at a height of 1.1–2 m. Logistic regression analysis indicated that the probability of occurrence of the species increases with the density of culms and percentage bamboo cover per ha. The home range of H. subflava is one of the smallest yet reported for a thamnophilid species, while the density of the bamboo-dwelling populations among the highest recorded for any Amazonian thamnophilid, including other bamboo forest specialists. The high degree of habitat specificity of H. subflava for bamboo-dominated environments makes the species vulnerable to the loss of its preferred habitat in the region.

Impact of livestock grazing on biodiversity and giant panda habitat

ABSTRACTLivestock grazing occurs in many protected areas for wildlife and has become a threat to wildlife worldwide. Livestock grazing within protected areas causes negative effects to rare wildlife (e.g., giant panda [Ailuropoda melanoleuca]) and their habitat. We used the 2,000‐km2 Wolong National Nature Reserve, Sichuan Province, southwestern China, to document the effects of livestock on the giant panda and its habitat. We monitored arrow bamboo (Bashania fangiana), wildlife sign (i.e., feces and tracks), and characteristics of plant communities in intact habitat (IH; limited livestock grazing) and disturbed habitat (DH; with grazing disturbance) to assess the effects of livestock grazing and the responses of giant pandas and sympatric species across spatial and temporal scales. Bamboo coverage and the height and basal diameter of bamboo in IH were greater than those in DH, whereas the number of herbaceous species and herbaceous coverage in IH were lower than those in DH. Wildlife signs in IH were greater than those in DH; specifically, giant panda and red panda (Ailurus fulgens) signs were greater, whereas signs of sambar (Rusa unicolor) and tufted deer (Elaphodus cephalophus) in IH were similar to those in DH. Livestock grazing reduced bamboo, which may threaten the long‐term survival of the giant panda. Our results have implications for understanding and management of livestock grazing in the Wolong National Nature Reserve and elsewhere. © 2019 The Wildlife Society.

Effects of sika deer (Cervus nippon) and dwarf bamboo (Sasa senanensis) on tree seedlings in a cool-temperate mixed forest on Hokkaido Island, Japan

Overabundant deer populations have direct and indirect effects on forest vegetation. For forest regeneration, it is important to identify the response of tree seedlings to deer browsing following a reduction in deer density. We examined the effects of deer density, dwarf bamboo coverage, light availability, and tree species on seedling survival and growth inside and outside deer-excluding fences, from 2009 to 2011 in a cool-temperate mixed forest on Hokkaido Island, Japan. The occurrence probability of browsing was high in the plots with high pellet density. Bamboo coverage decreased significantly with increased pellet density. The survival rate of seedlings was negatively affected by both the occurrence of browsing and bamboo coverage. The growth of seedlings was negatively affected by the occurrence of browsing. Our study showed that deer browsing had both a direct negative effect by decreasing seedling survival and an indirect positive effect by reducing bamboo coverage. These results suggest that we should examine browsing intensity and the response of forest vegetation and recognize the competitive and facilitative effects of neighbouring plants on tree seedlings.

The role of environmental heterogeneity for the maintenance of distinct bird communities in fragmented forests

ABSTRACTIf a forest fragment maintains original heterogeneous habitat conditions after deforestation and fragmentation of the landscape, is it possible that distinct communities can still remain within the forest remnant as they once occurred in the continuous forest landscape? In the present study, we assessed whether a single forest fragment could harbour different bird communities and the potential factors driving this distinction. Bird abundance and composition were compared between two distinct regions within a single large forest fragment, which differ in topography and vegetation physiognomy. The forest fragment was located in southern Brazil and consisted of pristine semi-deciduous forest. Our analysis indicates the occurrence of two different bird communities within the interior area of a single forest fragment. Variation partitioning also indicated that environmental features, particularly bamboo cover and humidity, were the main factors explaining bird species occurrence. We suggest that habitat heterogeneity is important for the maintenance of these bird communities and it leads to: (1) high levels of bird species diversity, and (2) maintenance of important ecological mechanisms (e.g. species sorting) within the forest fragment. Understanding the ecological processes involved in habitat distribution inside single forest fragments is important, yet usually not properly evaluated in forest fragmentation studies. Our results suggest that considering forest fragments as single ecological units can be misleading. We highlight the need to critically evaluate individual features of forest fragments, beside other landscape metrics, in order to identify important forest fragments for biodiversity conservation.

Effects of the occurrence of a cyclone and the dominance of a bamboo species on the dynamics of subtropical forest fragments

AbstractWith the intensification of global warming, the occurrence of large‐scale natural events is becoming even more common in tropical regions, which can impact the structure of plant communities. In this study, we evaluated the isolated and combined effects of an extratropical cyclone and the dominance of a native bamboo species (Merostachys skvortzovii) on floristic composition, diversity, demographic rates and the increment of trees in Atlantic Forest fragments in Southern Brazil. In 2014 (T1) and 2016 (T2), we sampled 56 plots of 200 m² for the effects of an extratropical cyclone in 2009 (T0). We also evaluated another 60 plots of the same size not in the direct path of this cyclone. Half of the plots in each group were covered by dense groupings of bamboos, as a result of past human activities, which could potentially limit natural regeneration. We observed an increase in richness and diversity indices (H′ and 1/D) from the first (T0) to the following assessments (T1 an T2) on the sites affected by the cyclone, when compared to non‐affected sites. After the cyclone, both density and basal area they decreased, but there was an increase in recruitment, mortality, turnover rates and basal area, as well as basal increment. The diameter increment on surviving individuals was higher in cyclone‐affected sites than in non‐affected sites. Bamboo cover did not affect richness or demographic rates (except mortality between T0 and T1). Natural impacts of this nature can lead to significant alterations of demographic rates, allowing the input of new species and influencing the pace of demographic processes.

Hierarchical Environmental Factors Affecting the Distribution of Abies koreana on the Korean Peninsula

A regional decline in the Korean fir (Abies koreana) has been observed since the 1980s in the subalpine region. To explain this decline, it is important to investigate the degree to which environmental factors have contributed to plant distributions on diverse spatial scales. We applied a hierarchical regression model to determine quantitatively the relationship between the abundance of Korean fir (seedlings) and diverse environmental factors across two different ecological scales. We measured Korean fir density and the occurrence of its seedlings in 102 (84) plots nested at five sites and collected a range of environmental factors at the same plots. Our model included hierarchical explanatory variables at both site-level (weather conditions) and plot-level (micro-topographic factors, soil properties, and competing species). The occurrence of Korean fir seedlings was positively associated with moss cover and rock cover but negatively related to dwarf bamboo cover. At the site level, winter precipitation was significantly and positively related to the occurrence of seedlings. A hierarchical Poisson regression model revealed that Korean fir density was negatively associated with slope aspect, topographic position index, Quercus mongolica cover, and mean summer temperature. Our results suggest that rising temperature, drought, and competition with other species are factors that impede the survival of the Korean fir. We can predict that the population of Korean fir will continue to decline in the subalpine, and only a few Korean fir will survive on northern slopes or valleys due to climate change.

"In a tree by the brook, there's a songbird who sings": Woodlands in an agricultural matrix maintain functionality of a wintering bird community.

The agricultural matrix has increasingly been recognized for its potential to supplement Protected Areas (PAs) in biodiversity conservation. This potential is highly contextual, depending on composition and spatial configuration of matrix elements and their mechanistic relationship with biological communities. We investigate the effects of local vegetation structure, and proximity to a PA on the site-use of different guilds in a wintering bird community within the PA, and in wooded land-use types in the surrounding matrix. We used occupancy models to estimate covariate–guild relationships and predict site-use. We also compared species richness (estimated through capture–recapture models) and species naïve site-use between the PA and the matrix to evaluate taxonomic changes. We found that tree cover did not limit the site-use of most guilds of the community, probably due to high canopy cover across all chosen sites. Exceptions to this were guilds comprising generalist species. Shrub cover and bamboo cover had important effects on some woodland-associated guilds, suggesting a change in limiting factors for site-use under adequate tree cover. Site-use across the matrix was high for all analyzed guilds. This was found to be due to three non-exclusive reasons: (i) presence of one or more ubiquitous species (found all across the landscape) within some guilds, (ii) redundancy of species within guilds that buffered against a decrease in site-use, and (iii) turnover in guild composition/abundances to more generalist species from PA to matrix. Estimated species richness was higher in the matrix (107± 11; mean ± SE) than in the PA (90± 7), which may have been in part due to the addition of generalist species in the matrix. Understanding factors that limit biological communities is crucial to better managing the ever-increasing matrix for biodiversity conservation. Our study provides insights into the effects of different components of vegetation structure on the bird community in wooded land-use types in the matrix. We highlight the value of woodlands surrounding PAs in maintaining multiple guilds, and hence, the functionality of a wintering bird community. However, we caution that the matrix may fall short in retaining some specialized species of the community.

Interactions among dwarf bamboo, litter and consumption by small vertebrates place multiple constraints on the establishment of native tree seedlings in a Japanese agricultural landscape

Faunal assemblage alterations due to anthropogenic impacts have changed herbivore–vegetation relationships in various ecosystems, but the influences of small vertebrates on revegetation processes remain unclear. In a peri-urban agricultural landscape in eastern Japan that lacks large ungulates but supports small generalist herbivores, fewer native seedlings have become established in thickets dominated by native dwarf bamboo, Pleioblastus chino (Franch. et Sav.) Makino. The mechanisms limiting tree seedling establishment are unknown. Our aim here was to evaluate the influence of interactions among the dwarf bamboo, its litter cover and small vertebrate herbivores on the microsite conditions governing the establishment of native tree seedlings from different successional stages in an old field in temperate Japan. First, seedling emergence and survival of seeded Pinus densiflora Siebold et Zucc., Celtis sinensis Pers., Aphananthe aspera (Thunb.) Planch., Quercus serrata Murray, Quercus myrsinifolia Blume and Castanopsis sieboldii (Makino) Hatus. ex T. Yamaz. et Mashiba were observed in a factorial design that accounted for the presence or absence of dwarf bamboo and its litter cover, as well as the exclusion or access of small vertebrate fauna, in 2009 and 2010. To identify small vertebrate herbivores that reduced the emergence or survival of tree seedlings in the first experiment, reseeding experiments using P. densiflora, C. sinensis, A. aspera and Q. myrsinifolia were conducted by video trapping in 2011 and video and still-camera trapping in 2012. The abiotic conditions under the dwarf bamboo were lethal to early- to mid-successional P. densiflora, C. sinensis, A. aspera and Q. serrata but led to better survival—although spindly growth—of late-successional Q. myrsinifolia and C. sieboldii. The main consumers and the plants they found palatable differed between the bamboo thickets and the intervening gaps. Predation by mice appeared to have severely limited the emergence of all species, particularly in the bamboo thickets but occasionally in the gaps, whereas litter cover slightly mitigated this limitation. However, bamboo litter cover reduced the emergence of P. densiflora in the gaps. Chinese bamboo partridge (Bambusicola thoracicus Temminck), an introduced game bird, selectively and severely fed on the cotyledons—and probably seeds—of A. aspera and moderately preyed upon those of P. densiflora in the gaps. Apparent consumption of seedlings in the gaps by the Japanese hare (Lepus brachyurus Temminck) suppressed the growth of all species but apparently did not severely affect emergence and survival. Thus, the net balance of positive and negative interactions at the bamboo thicket scale (i.e. the presence of dominant dwarf bamboo cover or intervening gaps and the herbivore behaviours in these two environments) and at the microsite level (i.e. litter cover) shapes the early establishment patterns of native tree seedlings, and this balance differs among tree seedling species.

Integrating indices to evaluate the effect of artificial restoration based on different comparisons in the Wanglang Nature Reserve

To develop the indices to evaluate the effects of artificial restoration during forest restoration, we tested the validity of indices integrated at the Wanglang Nature Reserve by studying the characteristics of an artificial forest based on different comparisons of primary forest, secondary forest, giant panda habitat, and the surrounding environment. The results indicated that the characteristics of the artificial forest and the different comparisons were well described and distinguished by the vegetation coverage, species composition and richness, community structure, tree growth status indices. The artificial forest was different from the primary forest in a number of woody plants in different layers; different from secondary forest in species richness and tree growth status; different from giant panda habitat in trees and bamboo; and different from the surrounding environment in bamboo coverage, species richness, and community structure. Meanwhile, the artificial forest had a more homogeneous tree size than the comparisons. Based on these results, we suggest that an evaluation of the effect of forest restoration should be related to specific factors, because the effects of artificial restoration differ depending on the evaluation standard. We conclude that the indices used in this study can be used to evaluate the effect of artificial restoration, which is useful for forest restoration in Wanglang Nature Reserve and elsewhere.