Bryophytes on tree trunks in natural forests, selectively logged forests and cacao agroforests in Central Sulawesi, Indonesia

Forest disturbance and transformations into agricultural land alter tropical landscapes at drastic rates. Here, we investigate bryophyte assemblages on trunk bases in natural forest, selectively logged forest and cacao agroforests that are shaded by remnants of natural forest in Central Sulawesi. Overall, bryophyte richness per site did not differ between forest types. However, mosses and liverworts reacted differently in that moss richness was lowest in cacao agroforests, whereas liverwort communities were equally rich in all forest types. In terms of cover, mosses remained unaffected while liverwort cover decreased significantly in disturbed forest. Species composition of bryophytes clearly changed in cacao agroforests as compared to natural forests and selectively logged forests. In particular some drought-sensitive species were rare or absent in cacao agroforests and were replaced by drought-tolerant ones, thus underlining the importance of microclimatic changes. Moreover, differences in bryophyte species composition between large and small trees were only pronounced in cacao agroforests, presumably due to concomitant changes in stemflow of precipitation water. In conclusion, the bryophyte assemblages of selectively logged forests and cacao agroforests were as rich as in natural forest, but species turn-over was particularly high towards cacao agroforests probably due to microclimatic changes. Maintenance of shade cover is crucial to the conservation of the drought-sensitive forest species.     

Local and landscape factors determine functional bird diversity in Indonesian cacao agroforestry

Large-scale intensification of smallholder cacao management is currently affecting the agroforestry landscapes of Sulawesi (Indonesia), the world’s third largest cacao producer. Little is known about how this shift from diverse plantations to full-sun cacao will affect functionally important biodiversity within the agroecosystem, and how this is related to landscape-wide patterns in land-use and natural ecosystems. We recorded birds in 43 cacao plots differing in woody and herbaceous vegetation as well as distance to forest in two valleys around the Lore Lindu National Park in Central Sulawesi. Species richness of frugivores and nectarivores decreased with increasing distance to forest, whereas granivorous birds increased in richness. Forest specialists, but not habitat generalists, responded positively to forest edge proximity. Species richness of all functional groups except seed eaters increased at higher density of tall shade trees. Greater species richness of shade trees was associated with higher species richness of frugivores and nectarivores, while herbaceous vegetation did not have a strong impact on the avifauna. The positive effect of shade trees was independent of distance to forest. In conclusion, our study shows the relative importance of local and landscape effects on bird diversity with shade trees being critical for bird conservation in cacao agroforestry landscapes.     

Use of remnant boreal forest habitats by saproxylic beetle assemblages in even-aged managed landscapes

Saproxylic Coleoptera are diverse insects that depend on dead wood in some or all of their life stages. In even-aged boreal forest management, remnant habitats left as strips and patches contain most of the dead wood available in managed landscapes and are expected to act as refuges for mature forest species during the regeneration phase. However, use of remnant habitats by the saproxylic fauna has rarely been investigated. Our objective was to characterize the saproxylic beetle assemblages using clearcuts and forest remnants in western Québec, Canada, and to explore the effects of forest remnant stand characteristics on saproxylic beetle assemblages. We sampled both beetle adults and larvae, using Lindgren funnels and snag dissection, in five habitat locations (clearcuts, forest interiors of large patches, edges of large patches, small patches and cut-block separators) from three distinct landscapes. Adult saproxylic beetles (all feeding guilds combined) had significantly higher species richness and catch rates in small patches compared to forest interiors of large patches; the phloeophagous/xylophagous group had significantly higher species richness only. Small patches, cut-block separators and edges of large patches also had the highest snag density and basal area, increasing habitat for many saproxylic beetles. No significant differences in density of saproxylic larvae were found between habitat patches, but snag dissection nevertheless suggests that snags in forest remnants are used by comparable densities of insects. Saproxylic beetles appear to readily use habitat remnants in even-aged managed landscapes suggesting that forest remnants can insure the local persistence of these species, at least in the timeframe investigated in our study.     

Drastic erosion in functional attributes of tree assemblages in Atlantic forest fragments of northeastern Brazil

The long-term dynamics of plant communities remain poorly understood in isolated tropical forest fragments. Here we test the hypothesis that tropical tree assemblages in both small forest fragments and along forest edges of very large fragments are functionally much more similar to stands of secondary growth (5-65-yr old) than to core primary forest patches. The study was carried out in a severely fragmented landscape of the Brazilian Atlantic forest. Nine functional attributes of tree assemblages were quantified by sampling all trees (DBH ? 10 cm) within 75 plots of 0.1 ha distributed in four forest habitats: small forest fragments (3.4-79.6 ha), forest edges, second-growth patches, and primary forest interior areas within a large forest fragment (3500 ha). These habitats were markedly different in terms of tree species richness, and in the proportion of pioneer, large-seeded, and emergent species. Age of second-growth stands explained between 31.4% and 88.2% of the variation in the functional attributes of tree assemblages in this habitat. As expected, most traits associated with forest edges and small forest fragments fell within the range shown by early (<25-yr old) and intermediate-aged secondary forest stands (25-45-yr old). In contrast to habitat type, tree assemblage attributes were not affected by vegetation type, soil type and the spatial location of plots. An ordination analysis documented a striking floristic drift in edge-affected habitats. Our results suggest that conservation policy guidelines will fail to protect aging, hyper-fragmented landscapes from drastic impoverishment if the remaining forest patches are heavily dominated by edge habitat.     

Long-term erosion of tree reproductive trait diversity in edge-dominated Atlantic forest fragments

Habitat loss and fragmentation promote relatively predicable shifts in the functional signature of tropical forest tree assemblages, but the full extent of cascading effects to biodiversity persistence remains poorly understood. Here we test the hypotheses that habitat fragmentation (a) alters the relative contribution of tree species exhibiting different reproductive traits; (b) reduces the diversity of pollination systems; and (c) facilitates the functional convergence of reproductive traits between edge-affected and early-secondary forest habitats (5-32 years old). This study was carried out in a severely fragmented 670-km² forest landscape of the Atlantic forest of northeastern Brazil. We assigned 35 categories of reproductive traits to 3552 trees (DBH ? 10 cm) belonging to 179 species, which described their pollination system, floral biology, and sexual system. Trait abundance was calculated for 55 plots of 0.1 ha across four habitats: forest edges, small forest fragments (3.4-83.6 ha), second-growth patches, and core tracts of forest interior within the largest available primary forest fragment (3500 ha) in the region. Edge-affected and secondary habitats showed a species-poor assemblage of trees exhibiting particular pollination systems, a reduced diversity of pollination systems, a higher abundance of reproductive traits associated with pollination by generalist diurnal vectors, and an elevated abundance of hermaphroditic trees. As expected, the reproductive signature of tree assemblages in forest edges and small fragments (edge-affected habitats), which was very similar to that of early second-growth patches, was greatly affected by both habitat type and plot distance to the nearest forest edge. In hyper-fragmented Atlantic forest landscapes, we predict that narrow forest corridors and small fragments will become increasingly dominated by edge-affected habitats that can no longer retain the full complement of tree life-history diversity and its attendant mutualists.     

The value of primary, secondary and plantation forests for Amazonian birds

Secondary forests and exotic tree plantations are rapidly expanding across tropical landscapes, yet we currently have a very poor understanding of the value of these human-dominated forest landscapes for biodiversity conservation. Mist netting, point counts and transect walks were used to compare the bird communities of these habitats and neighboring primary forest in north-east Brazilian Amazonia. The extensive spatial scale of plantations and second-growth in our study area enabled us to implement a robust replicated design, with survey plots approximately two to three orders of magnitude larger than most previous studies of land-use change in the tropics, thus minimising the influence of the surrounding landscape. Species richness was highest in primary forest and lowest in Eucalyptus plantations, and community turnover between habitats was very high whether based upon matrices of relative abundance or species presence-absence data, and for both point count and mist net data. Monthly line-transect censuses conducted over an annual cycle showed an increase in the detection of canopy frugivores and seed predators during the peak of flower and fruit availability in primary forest, but failed to suggest that second-growth or Eucalyptus stands provide suitable foraging habitat at any time of the year. The conservation value of both secondary forest and plantations was low compared to conclusions from previous studies. Our results indicate that while large-scale reforestation of degraded land can increase regional levels of diversity, it is unlikely to conserve most primary forest species, such as understorey insectivores and canopy frugivores.     

Rove beetles and ground beetles (Coleoptera: Staphylinidae, Carabidae) as indicators of harvest and regeneration practices in western Canadian foothills forests

Staphylinid beetle assemblages from coniferous foothills forest in west-central Alberta, Canada were studied via pitfall trapping to examine the effects of stand age and possible edge effects. Sites included a chronosequence of stands from 1 to 27 years post-harvest, and four types of mature forest that had not been disturbed by fire for at least 80 years. In all, 19 sites were sampled between 1989 and 1991. A total of 98 species were identified, nine of which are reported for the first time in Alberta. Staphylinids were more abundant in mature forest stands but assemblages were more diverse in regenerating stands. Thirty-four rove beetle species showed significant indicator value for particular stands or groups of stands, including mature forest, young forest, and open ground specialists. After harvesting, the catch rate of many forest species decreased dramatically, and open ground species were more commonly collected. Populations of some forest species remained active on logged sites for one or 2 years before disappearing. As stands regenerated, they were colonized by species characteristic of young stands, but true forest species were found only in older unharvested stands. The beetle assemblages from regenerating stands became more similar to those from mature stands as they aged, but still differed considerably from them 27 years after harvesting. Transects across forest-clearcut edges revealed a significant beetle response to habitat edges. Staphylinids assemblages were compared to the ground beetle (Carabidae) assemblage sampled via the same pitfall trapping regime. Mature forest specialists are threatened by fragmentation and loss of habitat. In order to conserve these beetle assemblages, forest managers should retain adequate patches of older successional stages on working landscapes.     

Eucalypt plantations as habitat for birds on previously cleared farmland in south-eastern Australia

In parts of Australia, extensive areas of cleared land are now being planted with commercial plantations of native eucalypts. Questions arise about the extent to which such plantations can rectify previous loss of habitat and contribute to biodiversity conservation. This study assessed abundance of bird species (as one aspect of biodiversity) on 105 sites (25 cleared land, 58 plantations and 22 native forest) in two regions of rural Victoria, south-eastern Australia. Generalised linear modelling was used to assess some of the landscape and habitat variables that contributed to the value of plantation sites for particular groups of bird species. These models demonstrated the importance of on-site habitat variables in explaining the abundance of groups of bird species, with landscape context making small additional contributions.Mean abundance of forest and woodland birds was higher in eucalypt plantations than cleared farmland, and marginally lower than in native forest. Patterns differed between bird guilds. For example, insectivores that forage in the canopy and tall shrub layers were at least as common in plantations as in native forest, with birds in the latter group using young eucalypts as if they were tall shrubs. Birds that forage from open ground among trees were more common in plantations than native forest, and may benefit substantially from the new habitat fortuitously provided for them. This group includes several species that have declined in natural woodland habitats. Nectarivores, carnivores and birds that forage among low shrubs were less common in plantations than in native forest. Insectivores that forage from eucalypt bark made little use of plantations. Different approaches to plantation design and management would be needed to cater for groups such as these. Specific measures include planting of rough-barked eucalypts in addition to smooth-barked species, and provision of artificial hollows. Retention of existing remnants of native forest (e.g. old trees and forest patches) is a priority, to supply habitat elements that would otherwise be missing for long periods.     

History and forest biodiversity of woodland key habitats in south boreal Sweden

Forest exploitation has destructed forest habitats in Fennoscandia during last centuries. Vital components of existing forest biodiversity have been identified as small (a few ha) woodland key habitats (WKHs). Many WKHs in boreal forest landscapes are assumed to represent remnant near-natural forests from before the phase of industrial forest exploitation. Thus, WKHs are supposed to (i) exhibit a low degree of exploitation, (ii) have old-growth characteristics and (iii) host Red-list species. Yet, WKHs’ history and biodiversity have not been systematically investigated. Thus, their conservation values remain unclear. This study investigates history and biodiversity of 15 WKHs in central Sweden with retrospective methods and field studies. We analyze (1) forest structure before, during and after the forest exploitation period, (2) existing biodiversity, i.e. species and structural elements, and (3) to what extent human activities (forestry) have influenced current biodiversity. Our results indicate that forest structure within the areas that currently are classified as WKHs has changed dramatically since the mid-19th century, when forests were unaffected by logging. The results suggest that fire-suppression during last century, gradually increased logging until mid-20th century and abandonment by modern forestry during the late 20th century, are main causes behind this transformation. Less than 10% of studied WKHs had biological features that resembled those of pristine boreal forests. Thus, most studied WKHs cannot be classified as near-natural or remnants of pristine forest. We suggest that the program for WKHs give more focus to pre-industrial forest structure, local historical aspects being seriously regarded and ecological restoration efforts being introduced.     

Green labelling,sustainability and the expansion of tropical agriculture: Critical issues for certification schemes

The expansion of agricultural plantations at the expense of forest drives dramatic losses of biodiversity and carbon. Consumers are now demanding sustainability in tropical agriculture and producers are responding with questionable certification standards. Many certification schemes—including those for oil palm, soy, sugar cane and cacao—rely upon the High Conservation Value (HCV) concept to prevent unacceptable losses of biodiversity to agricultural conversion. This concept protects very rare species or habitats, exceptional concentrations of wildlife, or large landscape-level areas of forest. Yet much biodiversity persists below these thresholds yielding the spectre of unsustainable conversion of forest to certified plantation crops under a green label. To meet more rigorous standards of sustainability, tropical plantations would have to retain large patches of native forests in the matrix. We highlight six critical areas in need of consideration by conservation scientists, practitioners and certification processes. In particular, the application of HCV to sustainable agricultural development at the national-level, the use of Imperata grasslands and abandoned agriculture, the creation of Biobanks, and increased price premiums for certified crops could redound to the long-term protection of tropical biodiversity.     

Conservation of beetles in boreal pine forests: the effects of forest age and naturalness on species assemblages

The effort of boreal forest conservation has emphasised the preservation of old-growth forests while the role of young successional stages in maintaining biodiversity has remained largely unstudied. We compared the richness of beetle species and composition of species assemblages between managed and seminatural forests in five stages of forest succession. The sites were in boreal sub-xeric pine-dominated forests in eastern Finland. Seminatural study sites, especially the recently burned sites, were important habitats for threatened and near-threatened species. We propose that young stages of natural succession should be included in the network of protected forest areas. On the other hand, the composition of saproxylic species assemblages in seminatural forests differed from the assemblages in managed forests, indicating also the need to improve the forest management guidelines so that they better address the requirements of species protection. Regeneration methods applied should resemble or mimic the natural disturbances more closely.     

The Brazilian Atlantic Forest: How much is left, and how is the remaining forest distributed? Implications for conservation

The neotropical Atlantic Forest supports one of the highest degrees of species richness and rates of endemism on the planet, but has also undergone a huge forest loss. However, there exists no broad-scale information about the spatial distribution of its remnants that could guide conservation actions, especially when systematic biodiversity data are not available. In this context, our objectives were to quantify how much of the forest still remains, and analyze its spatial distribution. We considered the entire Brazilian Atlantic Forest, and eight sub-regions, defined according to species distribution. The results revealed a serious situation: more than 80% of the fragments are <50 ha, almost half the remaining forest is <100 m from its edges, the average distance between fragments is large (1440 m), and nature reserves protect only 9% of the remaining forest and 1% of the original forest. On the other hand, our estimates of existing Atlantic Forest cover were higher than previous ones (7-8%), ranging from 11.4% to 16%. The differences among estimates are mainly related to our inclusion of intermediate secondary forests and small fragments (<100 ha), which correspond to approximately 32-40% of what remains. We suggest some guidelines for conservation: (i) large mature forest fragments should be a conservation priority; (ii) smaller fragments can be managed in order to maintain functionally linked mosaics; (iii) the matrix surrounding fragments should be managed so as to minimize edge effects and improve connectivity; and (iv) restoration actions should be taken, particularly in certain key areas. The clear differences in the amount remaining and its spatial distribution within each sub-region must be considered when planning for biodiversity conservation.     

Conversion of a tropical forest into agroforest alters the fine root-related carbon flux to the soil

Large areas of remaining tropical forests are affected by anthropogenic disturbances of various intensities. These disturbances alter the structure of the forest ecosystem and consequently its carbon budget. We analysed the role of fine root dynamics in the soil carbon budget of tropical moist forests in South-east Asia along a gradient of increasing disturbance intensity. Fine root production, fine root turnover, and the associated carbon fluxes from the fine root system to the soil were estimated with three different approaches in five stands ranging from an old growth forest with negligible anthropogenic disturbance to a cacao agroforestry system with planted shade trees. Annual fine root production and mortality in three natural forest sites with increasing canopy openness decreased continuously with increasing forest disturbance, with a reduction of more than 45% between the undisturbed forest and the forest with large timber extraction. Cacao agroforestry stands had higher fine root production and mortality rates than forest with large timber extraction but less than undisturbed forest. The amount of carbon annually transferred to the soil carbon pool through fine root mortality was highest in the undisturbed forest and generally decreased with increasing forest use intensity. However, root-related C flux was also relatively high in the plantation with planted shading trees. In contrast, the relative importance of C transfer from root death in the total above- and below-ground C input to the soil increased with increasing forest use intensity and was even similar to the C input via leaf litter fall in the more intensively managed agroforest. We conclude that moderate to heavy disturbance in South-east Asian tropical moist forests has a profound impact on fine root turnover and the related carbon transfer to the soil.     

Influence of tree characteristics and forest management on tree microhabitats

Higher densities of tree microhabitats in unmanaged forests may explain biodiversity differences with managed forests. To better understand the determinants of this potential biodiversity indicator, we studied the influence of tree characteristics on a set of tree microhabitats (e.g. cavities, cracks, bark features) on 75 plots in managed and unmanaged French forests. We hypothesized that the number of different microhabitat types per tree and the occurrence of a given microhabitat type on a tree would be higher in unmanaged than in managed forests, and that this difference could be linked to individual tree characteristics: diameter, vitality and species. We show that unmanaged forests contained more trees likely to host microhabitats (i.e. large trees, snags) at the stand level. However, at the tree level, forest management did not influence microhabitats; only tree characteristics did: large trees and snags contained more microhabitats. The number and occurrence of microhabitats also varied with tree species: oaks and beech generally hosted more microhabitats, but occurrence of certain types of microhabitats was higher on fir and spruce. We conclude that, even though microhabitats are not equally distributed between managed and unmanaged forests, two trees with similar characteristics in similar site conditions have the same number and probability of occurrence of microhabitats, whatever the management type. In order to preserve biodiversity, foresters could reproduce unmanaged forest features in managed forests through the conservation of specific tree types (e.g. veteran trees, snags). Tree microhabitats could also be more often targeted in sustainable forest management monitoring.     

Nestedness of bird assemblages in fragmented Afromontane forest: the effect of plantation forestry in the matrix

Bird species composition (61 species) of Afromontane forest fragments (n = 19) embedded in a natural grassland matrix or a plantation forestry matrix were compared. Forest bird assemblages in a natural grassland matrix displayed a nested non-random species distribution. Species loss was significantly area-dependent and predictable. Assemblages in the plantation-dominated matrix were also nested but were neither area- nor isolation-dependent and these potential processes had equal influence over bird species composition. Forests patches <50 ha in plantation were more species rich than those in a grassland matrix and visa versa for patches >50 ha. The effect of the matrix is revealed here with arboreal plantation cover promoting dispersal across the landscape, favouring abundant generalist bird species in smaller patches than expected in the plantation matrix, and the loss of some specialists and species living at low densities from large (>50 ha) patches. Because of a significant species-area relationship and possible area-dependent extinction, the largest forest patch in the nested series in a grassland matrix protects most bird species (89%). However, in a plantation matrix the absence of a species-area relationship requires the combination of many larger forest patches to protect most bird species. Plantation forests in the matrix significantly alter forest bird assemblage structure and composition. To avoid the effects of insularisation and to maintain the viability of bird communities in Afromontane forests requires conservation of the larger forests in a natural matrix. However, for forests in a plantation matrix, the management of dispersal processes by manipulation of the matrix may be as important to conserving species and communities as is minimising extinctions. Avoiding placing plantations near large forests, increasing the size of small patches, and where afforestation is unavoidable, placing plantations in the vicinity of small rather than large forest patches, are preferable management practices.     

Understory plant species and functional diversity in the degraded wet tropical forests of Kolombangara Island,Solomon Islands

Anthropogenic activities have resulted in extensive deforestation and forest degradation on many tropical oceanic islands. For instance, some islands in the Solomon archipelago have as little as 10% of primary forests remaining with few of these remnants protected from future land use change. We examine the plant species and functional diversity (excluding adult canopy trees) of 48 sites from four forest land use types (two types of primary forest, secondary forest and abandoned tree plantations) and two common human-maintained land use types (coconut plantations and grazed pastures) across three elevation bands on Kolombangara Island, Solomon Islands. In total, we surveyed 384 species from 86 families of which only 6.5% were non-native. Species richness was lowest in coconut plantations and grazed pastures and declined with increasing elevation across all land use types. Functional diversity was similar between primary and secondary forest (high richness, high evenness and unaltered dispersion) and lowest in coconut plantations and grazed pastures. Our results suggest that species and functional richness have had divergent responses to land use change in forest land uses indicative of a loss of functional redundancy. Despite structural and compositional similarities among primary forests and degraded forest land uses, full recovery of secondary and commercial plantations has not been achieved. We suggest that conservation of Kolombangara’s forest understory flora will require reserves across the island’s elevation gradient and may require active restoration in the future, particularly if degrading activities continue at the current rate.     

Burning biodiversity: Woody biomass use by commercial and subsistence groups in western Uganda’s forests

Woodfuels are the most heavily used energy source in sub-Saharan Africa. We analyzed the ecological impacts and modes of access of five user groups (domestic consumers, gin distillers, brick manufacturers, charcoal producers, and tea companies) drawing biomass energy from natural forests in western Uganda. While domestic consumers use the most species for fuelwood (>50), their consumption is likely sustainable because they generally harvest fast-growing species from fallows on their own land or their neighbors’. Charcoal producers prefer old-growth hardwood species and are responsible for the greatest loss of natural forests. They access forests by finding landholders who, either willingly or through coercion, allow trees on their lands to be cleared. The impact of charcoal production is exacerbated by a license system that undervalues natural forests and rewards rapid harvests across large areas. The tea industry consumes mainly eucalyptus wood (Eucalyptus spp.) from corporate plantations, but they indirectly create pressure on natural forests by hiring immigrants who subsequently settle in and clear forest remnants. If such practices continue, forest remnants will soon be exhausted, leaving Kibale National Park as the last natural forest in the region. Forest remnants are a vital source of water, medicinal plants, and energy for local citizens and to protect them from over-exploitation, policy makers should target the charcoal and tea industry for reform. Support for local land management institutions governing access to fallows and successional forests will inevitably enhance the policy interventions.     

Variation between mite communities in Irish forest types – Importance of bark and moss cover in canopy

Extensive afforestation took place in Ireland during the twentieth century and the forest cover currently represents about 10% of the land area. However, approximately 50% of this forest is Sitka spruce, a non-native species introduced from the North Western United States of America. Little is known about the microarthopods of these forests and the current study examined the mites (Oribatida and Gamasina) occurring in the canopy, moss (both on the soil surface and in the canopy) and soil of oak, ash, Scots pine and Sitka spruce forests in Ireland to compare the mite assemblages in each and to determine the associations between forest type and the form of constituent microhabitats in determining the structure of this fauna. There were significant differences between the diversity and species composition of the assemblages in the different forest types with the largest species richness occurring in oak forest and the smallest in first rotation Sitka spruce forest. Analysis of our data, together with the results from other studies, suggest that the differences arise because the variation between the architecture of the tree species is reflected in the structure of microhabitats such as the form of the bark and the extent of moss cover. Thus while the ultimate factors affecting the variation in the mite fauna may be the form of the microhabitats, these are intrinsic properties of the forests associated directly with the species of tree. Finally, our results do not support the view that exotic species will necessarily have low biodiversity of mites than native forests.     

Rapid deforestation and fragmentation of Chilean Temperate Forests

The temperate forests of Chile are classified a biological “hotspot” as a result of their high species diversity and high endemism. However, they are being rapidly destroyed, with significant negative impacts on biodiversity. Three land-cover maps were derived from satellite imagery acquired over 25 years (1975, 1990 and 2000), and were used to assess the patterns of deforestation and forest fragmentation in the coastal range of south-central Chile. Between 1975 and 2000, there was a reduction in natural forest area of 67% in the study area, which is equivalent to an annual forest loss rate of 4.5% per year using a compound-interest-rate formula. Forest fragmentation was associated with a decrease in forest patch size, which was associated with a rapid increase in the density of small patches (<100 ha), and a decrease in area of interior forest and in connectivity among patches. Since the 1970s, native forest loss was largely caused by an expansion of commercial plantations, which was associated with substantial changes in the spatial configuration of the native forests. By 2000, most native forest fragments were surrounded by highly connected exotic-species plantations. The assessment of forest loss and fragmentation provides a basis for future research on the impacts of forest fragmentation on the different component of biodiversity. Conservation strategies and land use planning of the study area should consider the spatial configuration pattern of native forest fragments and how this pattern changes over time and space at landscape level.     

Calcium concentration in leaf litter alters the community composition of soil invertebrates in warm-temperate forests

Many studies have shown the effects of aboveground plant species on soil organisms due to differences in litter quality. However, the calcium concentration in soil has received less attention as a controlling factor of soil invertebrate communities, even though it is an essential element for many animals, especially crustaceans. Litter of Japanese cedar (Cryptomeria japonica) plantations, which account for 19% of the forested area in Japan, has a higher calcium concentration compared to other taxa such as broad-leaved trees. We predicted that C. japonica plantations affect soil invertebrates by altering calcium availability. We compared soil properties including exchangeable calcium concentration and soil invertebrate communities between C. japonica plantations and natural broad-leaved forests. Exchangeable calcium was significantly higher in soil from cedar plantations than in that from broad-leaved forests. The invertebrate community composition differed between the two forest types and was best explained by the exchangeable calcium concentration. In particular, two major taxa of soil crustaceans (Talitridae and Ligidium japonicum) were found only in cedar plantations. Our results suggest that calcium concentrations in soil are altered in C. japonica plantations and that this affects soil invertebrate communities.