Unlogged Forest Research Articles

Direct comparisons of logging and agroforestry influence on tropical mammals in Sarawak, Borneo

AbstractTropical regions are undergoing rapid land use change, with major implications for global biodiversity. Selective logging and agroforestry are particularly widespread across tropical forests, often occurring in close proximity. But while a number of studies have addressed their impacts separately, few have directly compared how they influence forest vertebrates. Here, we assessed the occurrence of medium‐ to large‐bodied mammals in logged forest, unlogged forest, and agroforestry areas in three study areas in interior Sarawak, Malaysian Borneo. We detected 34 species across 99 camera trap locations and used multi‐species occupancy models to estimate species‐specific occurrence while accounting for imperfect detectability, spatial autocorrelation, natural habitat heterogeneity, and metrics of site accessibility (distance to human infrastructure) as proxies for potential hunting pressure. We found that species occurrences were unaffected by the distance to the nearest road or village and only responded to elevation and the distance to the nearest river in a single species each. Detection rates tended to vary with micro‐habitat characteristics such as the size of tree stumps and the prevalence of trees and rattan palms, which are often not considered in camera‐based occupancy studies. Occurrence rates of five species varied across habitat types but were not detectably lower in agroforestry sites than in unlogged forest for any species. Our results indicate that without unsustainable hunting, agroforestry and logged forest provide usable habitat for some, though not all, rainforest mammals. We also suggest that camera trap studies may benefit from the incorporation of fine‐scale habitat information into detectability estimation.Abstract in Malaysian is available with online material.

Distribution of Liana Richness and Abundance in the Forest of Papua New Guinea

This study surveys liana communities at 26 sites across undisturbed and disturbed forests from 70 to 2,700 m above sea level in northern parts of Papua New Guinea (PNG). The assessment was conducted following the Papua New Guinea National Forest Inventory (NFI) manual. The results show a total diversity of 68 genera of lianas, belonging to 33 families. No significant difference was observed in abundance of liana species between lowland unlogged (i.e., primary and pristine) and logged (disturbed) forests and lower montane unlogged forests. Richness is not significantly different between lowland and montane sites, as opposed to outcomes in other studies which have often reported a decrease in species richness with elevation. Both types of lowland forests do not show indicator genera, while the unlogged montane forests are characterized by Rubus and Sabia genera. The study shows a high taxonomic richness of lianas in PNG, supporting previous research and underlining that they make a significant contribution to the overall woody species richness and to the ecology and complexity of PNG forest.

Selective logging of a subtropical forest: Long-term impacts on stand structure, timber volumes, and biomass stocks

Long-term studies are key to understanding the dynamics of managed forests, especially as related to timber supplies. We evaluated 20 years of recovery of pre-harvest structure, biomass, and timber stocks of a Subtropical Atlantic Forest in Argentina subjected to either conventional selective logging (CL = ∼15 m3 ha−1) or reduced-impact logging (RIL = ∼11 m3 ha−1); we also monitored the dynamics of interspersed plots of unlogged forest (Control). All trees ≥10 cm DBH were measured before and at variable intervals for 20 years post-logging; the results are presented for all stems and for only those of species that provide commercial timber. After logging, basal areas and volume of all stems increased two-times faster after CL than after RIL, whereas biomass increments were similar between logged treatments. In contrast, commercial timber tree stocking did not recover regardless of the harvesting system applied. Mortality rates were high in both CL and RIL plots but also in unlogged Control plots (1.6–3.6 % year−1). The failure of timber stocks to recover was apparently due to high tree mortality rates coupled with the proliferation of understory bamboos. Alternative silvicultural methods are clearly needed to avoid degrading the remaining species-rich Subtropical Atlantic Forest.

A decade of diversity and forest structure: Post-logging patterns across life stages in an Afrotropical forest

Tropical forests are under threat of increasing pressure from income-generating land uses. Selective logging is a compromise that allows use of the land while leaving much of the forest canopy intact across a landscape. However, the ecological impacts of selective logging are unclear, with evidence of positive, negative, and negligible effects on forest structure and diversity. We examined the impact of selective logging on the structure and diversity of evergreen tropical forest in the Monts de Cristal region, a chain of mid-elevation hills in northwestern Gabon. For three size classes (seedling, sapling, and adult) of woody plant species, we tested whether forest structure (canopy openness, stem density, basal area, and relative liana abundances) and diversity were altered in forests that had been logged one year and ten years prior, compared to unlogged forest. In general, we found no large impact of selective logging treatment on the structure and diversity of adult woody plant communities, but the seedling and sapling communities were affected. Compared to unlogged forest, one-year post-logging forest had greater variation in canopy openness and lower sapling stem density. Ten-year post-logging forest had higher seedling and sapling species evenness, higher sapling species diversity, and higher relative abundance of sapling-sized lianas compared to unlogged forest. Our results show that key differences between intact and selectively logged forests persist in the understory at least a decade after logging. Overall, these results contribute an additional data point in the literature on selective logging, specifically representing the impacts of very low impact selective logging in Central African forests. Our study highlights the value of exploring selective logging impacts at multiple time periods of recovery, and makes an important contribution to the knowledge Central African managed forests.

Habitat fragmentation and logging affect the occurrence of lesser mouse-deer in tropical forest reserves.

Due to rapid urbanization, logging, and agricultural expansion, forest fragmentation is negatively affecting native wildlife populations throughout the tropics. This study examined the effects of landscape and habitat characteristics on the lesser mouse‐deer, Tragulus kanchil, populations in Peninsular Malaysia. We conducted camera‐trap survey at 315 sampling points located within 8 forest reserves. An assessment of site‐level and landscape variables was conducted at each sampling point. Our study provides critical ecological information for managing and conserving understudied populations of T. kanchil. We found that the detection of T. kanchil was attributed to forest fragmentation in which forest patches had four times greater detection of T. kanchil than continuous forest. The detection of T. kanchil was nearly three times higher in peat swamp forest compared to lowland dipterocarp forests. Surprisingly, the detection of T. kanchil was higher in logged forests (logging ceased at least 30 years ago) than unlogged forests. The detection of T. kanchil increased with the presence of trees, particularly those with DBH of 5 cm to 45 cm, canopy cover, number of saplings and palms, number of dead fallen trees, and distance from nearest roads. However, detection decreased with a greater number of trees with DBH greater than 45 cm and higher elevations, and greater detections where creeping bamboo was abundant. We recommend that conservation stakeholders take the necessary steps (e.g., eradicating poaching, habitat degradation, and further deforestation) to support the conservation of mouse‐deer species and its natural habitats.

Forest logging is associated with shape of males and gynes in the wood ant Formica aquilonia

Environmental stress can affect individual development and fitness in insects. Forest logging is a serious environmental stress for forest-specialist insects, such as the mound-building wood ant Formica aquilonia Yarrow 1955, which builds its nests into forests and is dependent on the nutrition provided by the forest habitat. We studied whether the logging causes such a strong environmental stress that it would be visible in disproportionate growth and shape of young winged wood ant gynes (‘queens’) and males. We measured head width, thorax width and wing length of 144 gynes and 100 males from 12 nests from six clear-cut areas, 11 nests from unlogged forest stands and 10 nests in clear-cut—forest margins. We observed disproportionate growth of different body parts and allometric growth of wings in both sexes in areas with different logging-induced disturbance. Gynes had larger heads in clear-cut areas and males had narrowest thoraxes in forest clear-cut edges. With an increasing thorax width, the wing length decreases steeper in clear-cuts than in other habitats in gynes and increases steeper in clear-cuts than other habitats in males. It seems that in a strongly disturbed clear-cut environment, the gynes invest the growth of head width. There seems to be a trade-off between the growth of the thorax and wings in gynes but not in males. The altered body shape may be adaptation to clearings caused by storm events of wild fires, but not forest management practices of modern era. Large-headed gynes may be better in a colony take-over, needed for the establishment of new colonies in early succession stage habitats in this temporally social parasitic species. Long-winged males may have better long-range flight ability, and they may thus have better fitness and change to disperse their genes onto new habitats.

Seed dispersal by spider monkeys in logged and unlogged sites in the Calakmul tropical humid forest, Mexico / Dispersión de semillas por monos araña en sitios talados y no talados en el bosque húmedo tropical de Calakmul, México

Seed dispersal by animals can be negatively affected by selective logging, but effects such changes in critical food resource, quality of food resources and food availability on seed dispersal and seedling recruitment, remains poorly understood. We investigated how selective logging, impacts the quantity of seed dispersal, focusing on highly frugivorous primate Ateles geoffroyi yucatanensis in Calakmul, Mexico. We assessed whether seed dispersal by the spider monkey differs between a logged and an unlogged site in the Calakmul tropical humid forest, Mexico. We recorded seeds in monkey faeces, including those deposited in latrines under sleeping trees (aggregated seed dispersal) and those dispersed across the forest (scattered seed dispersal) during a 5-mo period. The use of sleeping tree was similar in both forest conditions, averaging (± SD) 4.5 ± 4.3 weeks. They deposited 15,853 seeds (1–35 mm in length) from 20 tree species under sleeping trees, but seed abundance was 2.2 times higher in unlogged forests. Scattered seed dispersal (997 seeds from nine species) followed the opposite pattern, with 2.3 times more seeds in logged forests. The number of seeds and species per faecal sample did not differ between forest types, averaging 9.4 ± 20.2 seeds from 1.0 ± 0.8 seed species. Most (95%) scatter-dispersed seeds were undamaged in both forest types. These findings suggest that primate quantity seed dispersal is not limited in logged forests, potentially contributing to the recovery of these managed forests.

Changes in tree functional composition and forest functioning ten years after logging and thinning interventions in Bornean tropical forests

Examining ecosystem functioning of logged-over forests requires a quantitative trait-based monitoring approach, in addition to a taxonomic approach, which allows for evaluation of the accompanying shifts in species traits and functional composition. Our study evaluated forest regrowth after different logging and thinning techniques applied to 60 one-hectare forest subplots in East Kalimantan that were logged using selective conventional and reduced-impact techniques. We used seven functional traits to compare the short-term (∼1-year) and longer-term (∼10-year) changes in functional diversity and composition of the forest. Both conventional and reduced impact logging resulted in higher functional diversity after 10 years, but forest functional traits shifted away from those observed in unlogged (control) subplots. Reduced-impact logging led to smaller deviations in functional composition compared to unlogged forest. We found that low-intensity reduced-impact logging, i.e., <3 m2 ha−1 (equivalent to 5 trees ha−1 or approximately 42 m3 ha−1), maintained functional diversity equivalent to unlogged forest measured in 12 one-hectare control plots. Selectively logged forest subplots with liberation thinnings increased functional diversity while leaving the trait composition unchanged. Thinned subplots exhibited higher functional diversity than the un-thinned subplots and greater similarity to unlogged forest. However, high-intensity thinning, i.e., >10 m2 ha−1, resulted in large functional traits shifts away from unlogged forest. Our study suggests that preserving the original forest functionality, i.e., by applying low intensity, reduced-impact logging and thinning operations, represents a sustainable strategy for long-term tropical forest management.

Turnover-driven loss of forest-dependent species changes avian species richness, functional diversity, and community composition in Andean forest fragments

Andean forests, a hotspot of biodiversity, have suffered extensive fragmentation, yet we have little understanding of how this process has affected biodiversity. We surveyed bird communities across a gradient of fragment sizes (10–170 ha) and a continuous forest reference site in the Colombian Western Andes. Using a multi-species occupancy model to combine survey data from audio-visual transect surveys, mist netting, and playbacks for owls, we estimated alpha and beta taxonomic and functional diversity. We asked whether (1) habitat amount (patch size), edge effects, or selective logging affect bird occupancy and drive changes to diversity, (2) functional and taxonomic diversity respond similarly to fragmentation, and (3) compositional changes result from species turnover or nested species loss. Species richness declined with decreasing habitat amount, increasing edge density, and increasing disturbance through selective logging. These effects were driven by the loss of forest-dependent species, which were also area sensitive: 30 such species were absent from fragments, even the largest ones (>150 ha). Area-sensitive species were also edge sensitive and increased in occupancy in unlogged forest. We further found high beta diversity (0.78) driven by species turnover (85% of dissimilarity) along the gradient. Despite extensive turnover to non-forest species within functional groups, functional trait richness and dispersion significantly declined with habitat amount. Small fragments may mimic the structure and composition of early-successional Andean forests, driving spatial turnover patterns favoring disturbance-adapted species at the expense of primary-forest specialists. Large forest reserves are therefore required to conserve forest-dependent Andean birds.

Post-logging effects on nest predation and avian predator assemblages in a subtropical forest

Logging represents one of the main threats to bird populations breeding in subtropical forests because the resulting changes in forest structure influence nesting sites and predator–prey interactions. Nest site selection in birds is critical to their survival and reproductive success, because site characteristics can affect predation rates. The aim of this study is to evaluate the abundance of avian nest predators and the rate of predation on artificial nests in post-logging piedmont forests from the southern Yungas. Predation rate on artificial nests was lower in logged forest when compared to unlogged forest. This result may not only be explained by the influence of both micro- and meso-site which provided greater nest concealment, but also by the decrease in density of generalist predators at logged sites. As generalist predators were associated with vegetation cover, lower coverage may be affecting predator density at logging forests. The density of nestling predators, however, was higher in logging forests and was associated with this treatment. Our study suggests that post-logging effects changes the nesting sites and reduce the predation rate on artificial nests as well as the density of nest avian predators like Plush-crested Jay (Cyanocorax chrysops).

Impacts of tropical selective logging on local-scale movements of understory birds

Widespread selective logging in tropical forest causes structural damage and associated shifts in species composition, but we lack understanding of how selective logging impacts mechanistic processes that drive these biodiversity changes. Movement is a vital mechanistic process underpinning demographic, ecological, and evolutionary processes that likely determine species responses to logging. We assessed how tropical selective logging impacts local movements of 71 understory avian species in Sabah, Malaysian Borneo, and determined whether movement patterns relate to species' conservation status, functional traits, sensitivity to logging and trophic position. We used a capture-mark-recapture methodology and a hierarchical Bayesian framework to model maximum observed local movement distances, accounting for spatial sampling heterogeneity. Across the avian community, we found a higher probability of moving shorter distances (up to 200 m) in logged forests, and higher movement probability at longer distances (above 200 m) in unlogged forests. Altered movement patterns after logging may reflect increased understory density, changed resource distribution and/or predation risks, and suggest smaller home-range sizes. Species' conservation status, body mass, foraging guild, logging sensitivity and trophic position were unrelated to the magnitude of movement change. The continued persistence of understory species in our sample after selective logging may depend on flexibility in movement behaviour, conferring resilience to habitat degradation and the retention of high conservation values. This lends further support for the protection of these logged forests for biodiversity conservation.

Persistent Effects of Historical Selective Logging on a Vascular Epiphyte Assemblage in the Forest Canopy of the Western Ghats, India

Forest canopies have been dubbed the last biological frontier and continue to remain underexplored. Vascular epiphytes form a rich assemblage of plants within the forest canopy and apart from sustaining diverse taxa, they also fulfill critical ecological functions. Vascular epiphytes are particularly sensitive to perturbations of microclimate and microhabitat within the canopy, especially from anthropogenic changes such as logging. The forests of the megadiverse Western Ghats in India harbor a rich assemblage of vascular epiphytes, but their ecology has not been examined systematically. We compared the diversity, abundance, and composition of a vascular epiphyte assemblage between an unlogged and a historically selectively logged forest in the southern Western Ghats, India, and identified factors affecting the epiphyte assemblage. Canopies of 100 trees each in selectively logged and unlogged forests were accessed using the single-rope technique. We found 20 species of vascular epiphytes with the assemblage dominated by members of Orchidaceae. The diversity and abundance of epiphytes were significantly greater in the selectively logged forest. One host tree, Cullenia exarillata, supported the greatest number of epiphytes in both forest stands. The niche widths of epiphyte species, computed with host tree species as a resource, were similar between the two stands but a greater number of species pairs overlapped in the selectively logged forest. Overall, epiphyte abundance was negatively associated with unlogged forests. Host tree species, tree height, and presence of moss on branches were positively associated with the abundance of epiphytes. Despite being ecologically important, no study has thus far examined the impact of selective logging on the epiphyte assemblage in the Western Ghats. Our findings contribute to the knowledge of vascular epiphytes from South and Southeast Asia and set the stage for future research and conservation.

Use of response guilds of understory birds in threatened subtropical forest to monitor selective logging impact

Unplanned logging is one of the greatest current threats to native forests biodiversity. About 90% of the piedmont forest in the Southern Andean Yungas has been converted to other land-use types and the remaining forests fragments are being intensively logged without management plans. Bird species, especially understory birds, are good indicators of forest diversity and integrity. The aim of this study was to identify understory bird species associated with changes in the forest structure caused by selective logging and to explore whether it is possible to use these species as a monitoring tool. We observed that Sittasomus griseicapillus, Turdus rufiventris, Lepidocolaptes angustirostris, Casiornis rufus, Thraupis sayaca, and Tolmomyias sulphurescens were associated to unlogged sites with higher density of timber-yielding and standing dead trees. Thamnophilus caerulescens, Leptotila megalura, Synallaxis scutata, Poecilotriccus plumbeiceps, and Catharus ustulatus were favoured by logging activities and associated with understory visual obstruction. Mean cut-off abundance thresholds were 2.74 ind/ha for the avian guild associated with unlogged forest and 1.79 ind/ha for the guild associated with logged forest. Sustainable forest management schemes need to retain the understory visual obstruction at values similar to those of unlogged forest (43.75%), together with an adequate density (≥10 ind/ha) of standing dead trees with at least 19.5 cm in DBH, and a minimum of 210 ind/ha of timber tree species. Bird species identified in this study can be used in monitoring schemes to evaluate the implementation of these guidelines.

Impacts of selective logging on haemosporidian infection and physiological correlates in tropical birds

Tropical forest degradation affects host-parasite interactions, determining the probability of animals acquiring an infection. The activation of an immune response to fight off infections requires energy and other resources such as antioxidants which may be redirected from growth and reproduction. A key question is how selective logging—the most common form of tropical forest degradation—impacts the prevalence of avian haemosporidian infection and its correlated physiological responses (nutritional and oxidative status markers). We investigated the prevalence of Plasmodium, Haemoproteus, and Leucocytozoon parasites in 14 understorey bird species in lowland, logged and unlogged, old-growth forests of Borneo. Prevalences of infections were similar between selectively logged and unlogged forests. To explore nutritional and oxidative status effects of haemosporidian infections, we examined associations between infections and plasma proteins, plasma triglycerides, and multiple blood-based markers of oxidative status, testing for an impact of selective logging on those markers. Birds infected with Plasmodium showed higher levels of plasma proteins and non-enzymatic antioxidant capacity, and lower levels of plasma triglycerides and glutathione, compared with haemosporidian-free individuals. Conversely, birds infected with Haemoproteus showed no changes in nutritional or physiological markers compared with uninfected individuals. These results indicate higher metabolic and physiological costs of controlling Plasmodium infection, compared with Haemoproteus, possibly due to higher pathogenicity of Plasmodium. Selectively logged forests had no effect on the responses of birds to infection, suggesting that the environmental conditions of degraded forests do not appear to induce any appreciable physiological demands in parasitised birds.

The Effect of Forest Management on the Avifauna of a Brazilian Dry Forest

The conversion of tropical habitats has dramatic implications on biodiversity and represents one of the greatest conservation challenges of our time. Seasonally Dry Tropical Forests (SDTF), which are disjointly distributed throughout the Neotropics, are especially susceptible to human activities. The Caatinga Dry Forest, located in the semi-arid interior of northeastern Brazil, represents not only the largest and most biologically diverse nucleus of SDTF, but also the world’s most densely populated semi-arid region, with ever-growing pressure on its natural resources. To prevent illegal logging, conservation agencies looked at forest management, where an area is divided in smaller stands which are gradually logged and allowed to regrow for a period of time, when a new cutting cycle should reinitiate. The impacts of these management schemes on biodiversity, however, remain largely untested. We conducted standardized avian surveys to evaluate the effects of forest management on the avian community at a 1,670 ha privately owned property located on the Chapada do Araripe, northeastern Brazil. This area was divided in 22 forest stands, half of which had already been logged at the time of our sampling, creating a gradient of logged and natural forests and an 11-yr chrono-sequence of forest regeneration. Our results show that logged areas present fewer individuals, fewer species, and different avian assemblages than unlogged forests. Such differences are mostly driven by forest-dependent species, which were overwhelmingly affected by forest management. Our results show that although logged forests tend to recover its height after a decade, they do not recover the originally forest cover, measured by the Normalized Difference Vegetation Index. Likewise, decade-long recovering stands continue to show lower species richness, lower bird abundance, and different avian composition than unlogged forests. We identified a set of bird species that are more affected by forest management (ecological losers) and a group of birds that apparently benefit from the referred changes in land use (ecological winners). We conclude that completely managing an entire area may cause the extirpation of several forest-dependent species. We therefore suggest keeping logged and unlogged plots intermingled, to avoid local extinctions and the complete modification of the original avifauna.

Logging effects on seedling regeneration and diversity in a tropical moist semi-deciduous forest in Ghana

ABSTRACT The effect of time lag after logging on seedling dynamics was assessed in logged and unlogged forest plots located in the Pra-Anum Forest Reserve. Remnant tree attributes were sampled in six plots with sizes of 25 × 25 m in each forest type. Within each forest type, ten subplots with sizes 1 × 1 m were established for sampling seedling regeneration dynamics. Enumerated seedlings were grouped as pioneer, non-pioneer light demander, and shade-tolerant species. Regenerating seedlings were more diverse in the recently logged forest area characterised by Broussonetia papyrifera and Musanga cecropioides, and least in the unlogged forest driven predominantly by Celtis mildbraedii and Baphia nitida. Pioneer species were primarily dominant in the recently logged forest, while shade-tolerant and non-pioneer light-demanding species characterised the logged-over forest. Species richness and canopy openness of remnant stands explained 32 percent of the variations in regeneration richness between the logged and unlogged areas. Twenty-seven percent of the variations in seedling abundance was also explained by remnant trees richness, their size diameter and the degree to which their canopy has been opened. Logging-induced disturbance favours the sporadic emergence of pioneer species in recently disturbed areas which are later replaced by non-pioneer light-demanding or shade-tolerant species as light becomes limiting in the understory.

Life in the Canopy: Using Camera-Traps to Inventory Arboreal Rainforest Mammals in Borneo

Arboreal mammals form a diverse group providing ecologically important functions such as predation, pollination and seed dispersal. However, their cryptic and elusive nature, and the heights at which they live, makes studying these species challenging. Consequently, our knowledge of rainforest mammals is heavily biased towards terrestrial species, limiting our understanding of overall community structure and the possible impacts of human-induced disturbance. We undertook the first in-depth appraisal of an arboreal mammal community in Southeast Asia, using camera-traps set in unlogged and logged tropical rainforest in Sabah, Borneo. Using paired canopy and terrestrial camera-traps at 50 locations (25 in unlogged forest, 25 in logged), we assessed the effectiveness of camera-trapping at characterising the arboreal versus terrestrial community, and tested the influence of strata and forest type on community structure and composition. The paired design detected 55 mammal species across 15,817 camera-trap nights (CTNs), and additional canopy sampling in a subset of trees added a further two arboreal species to the inventory. In total, thirty species were detected exclusively by terrestrial camera-traps, eighteen exclusively by canopy camera-traps, and nine by units set at both heights, demonstrating significant differences between arboreal and terrestrial communities. This pattern was strongest in unlogged forest, reflecting greater structural diversity of this habitat, but held in logged forest as well. Species accumulation curves revealed that canopy camera-trapping significantly boosted species inventories compared to terrestrial-only sampling, and was particularly effective at detecting gliding mammals, rodents and primates. Canopy inventories took longer to reach an asymptote, suggesting that a greater sampling effort is required when deploying canopy camera-traps compared to those set on the ground. We demonstrate that arboreal mammals in Borneo’s rainforest form a diverse and distinct community, and can be sampled effectively using canopy camera-traps. However, the additional costs incurred by sampling in the canopy can be substantial. We provide recommendations to maximise sampling effectiveness, while bringing down costs, to help encourage further study into one of the last frontiers of tropical forest research.

Ground-dwelling spider families and forest structure variables for monitoring ecologically sustainable logging operations

SummaryApproximately 80% of neotropical forests are subject to unsustainable economic practices, such as logging. Spiders are a megadiverse taxonomic group with a particularly great diversity in forest ecosystems and could help indicate the sustainability of logging operations. At six sites at 400–700 m altitude in the piedmont forest of north-western Argentina, spiders collected using pitfall traps and forest structure and spider assemblage structure variables were quantified in order to examine the association between them and to identify indicator spider families. Logging changes forest structure and seems to generate an unsuitable habitat for spiders associated with mature forests. The family taxonomic level is a good surrogate for spider morphospecies. The Mysmenidae, Nemesiidae, Theridiidae, Pholcidae, Hahniidae and Tetragnathidae families were associated with upper canopy cover of 20% or more and with more than two dead fallen trees per 0.1 ha and &gt;15 live trees per 0.1 ha, found in unlogged forests. Bearing in mind that the piedmont forest of north-western Argentina is being logged in the absence of sustainability criteria, we suggest including spiders in monitoring schemes to complement the information obtained from more readily used groups, such as charismatic vertebrates.

Reconciling resource extraction and species conservation in a multi-use landscape: Immediate and long-term impacts of logging on rainforest mammal diversity

Tropical forest ecosystems are the most species-rich in the world and face intense pressures from land conversion. If done well, selective logging can be an important way of supporting local economies while minimally impacting wildlife. However, most studies on how selective logging affects wildlife come from sites that have been logged some time ago, often a decade or more. Here we assess how logging affects species assemblages in the very short term, immediately after the cessation of timber operations. We estimated overall mammal species richness in unlogged forest, previously logged forest, and an active logging concession in Indonesian Borneo using rarefaction-extrapolation-based diversity estimators. We found that estimated species richness did not differ significantly between unlogged forest (15.5 ± 2.82 species), previously logged forest (14.5 ± 2.10), or recently logged sites (14.2 ± 1.45) sites. Our findings suggest that the short-term impacts of properly managed selective logging are on par with the longer-term impacts that have been assessed in many prior studies.

Medium and long term effects of logging systems on forest structure and composition in the tropical rainforest of Suriname

ABSTRACT In this study, we compared the medium and long-term effects of logging on tropical rain forest ecosystems in Suriname using reduced impact logging (RIL), CELOS Management System (CMS), and conventional logging (CL) with forest without logging (NAT). In 18 forest plots with different times since logging ended and 9 unlogged forest plots, assessments were conducted on indicators of forest structure and vegetation composition. These indicators were then modelled as a function of management type and plot age. Multivariate ordination was used to visualize forest structure and vegetation composition differences between plots. High vegetation cover in the tree layer was more related to the older RIL and the CL plots, while high vegetation cover in the sapling and seedling layer related more to the CMS and NAT plots. Canopy openness was more related to the NAT, the CMS and the younger RIL plots. Furthermore, the CMS plots, which were logged 30 years ago, still did not reach the basal area of commercially important primary forest species, compared to unlogged forest. Both RIL and CMS plots have a strong presence of secondary species. This study shows the importance of applying the RIL technique correctly and taking forest characteristics and ecological processes into account when developing forest management principles. Forest management systems should also be flexible enough to adapt to area-specific requirements, for example, increasing the rotation cycle if the timber volume is not on the desired level. In this way, both conservation and economic goals are reached.