Selective logging in tropical forests may lead to deforestation and forest degradation, so accurate mapping of it will assist in forest restoration, among other ecological applications. This study aimed to track canopy tree loss due to illegal logging of the important hardwood tree Ocotea usambarensis in a closed-canopy submontane tropical forest by evaluating the mapping potential of the very-high-resolution WorldView-3 multispectral dataset using random forest (RF) and support vector machine (SVM) with radial basis function kernel classifiers. The results show average overall accuracies of 92.3 ± 2.6% and 94.0 ± 2.1% for the RF and SVM models, respectively. Average kappa coefficients were 0.88 ± 0.03 for RF and 0.90 ± 0.02 for SVM. The user’s and producer’s accuracies for both classifiers were in the range of 84–100%. This study further indicates that vegetation indices derived from bands 5 and 6 helped detect canopy gaps in the study area. Both variable importance measurement in the RF algorithm and pairwise feature selection proved useful in identifying the most pertinent variables in the classification of canopy gaps. These findings could allow forest managers to improve methods of detecting canopy gaps at larger scales using remote sensing data and relatively little additional fieldwork.

Extensive areas of tropical forests have been, and continue to be, disturbed as a result of selective timber extraction. Although such anthropogenic disturbance typically results in the loss of biodiversity, many species persist, and their conservation in production landscapes could be enhanced by a greater understanding of how biodiversity responds to forest management practices. We conducted intensive camera-trap surveys of eight protected forest areas in Sabah, Malaysian Borneo, and developed estimates of Sunda clouded leopard Neofelis diardi population density from spatially explicit capture–recapture analyses of detection data to investigate how the species’ abundance varies across the landscape and in response to anthropogenic disturbance. Estimates of population density from six forest areas were 1.39–3.10 individuals per 100 km2. Our study provides the first evidence that the population density of the Sunda clouded leopard is negatively affected by hunting pressure and forest fragmentation, and that among selectively logged forests, time since logging is positively associated with abundance. We argue that these negative anthropogenic impacts could be mitigated with improved logging practices, such as reducing the access of poachers by effective gating and destruction of road access points, and by the deployment of anti-poaching patrols. By calculating a weighted mean population density estimate from estimates developed here and from the literature, and by extrapolating this value to an estimate of current available habitat, we estimate there are 754 (95% posterior interval 325–1,337) Sunda clouded leopards in Sabah.

When timber harvesting is an important source of local income and forest resources are declining, even forests that are designated as protected areas may become vulnerable. Therefore, regular monitoring of forest disturbance is necessary to enforce the protection of forest ecosystems. However, mapping forest disturbance with satellite imagery can be complicated if the majority of the harvesting is selective logging and not clearcuts. Our goal was to map both selective logging and clearcuts within and outside of protected areas in Western Siberia, a region with a highly developed timber industry. Combining summer and winter imagery allowed us to accurately estimate not only clearcuts, but also selective logging. Winter Landsat images substantially improved our classification and resulted in a highly accurate forest disturbance map (97.5% overall accuracy and 86% user accuracy for the rarest class, clearcuts). Selective logging and stripcuts were the dominant disturbance types, accounting for 96.3% of all forest disturbances, versus 3.7% for clearcuts. The total annual forest disturbance rate (i.e. disturbance rate for clearcuts, stripcuts and selective logging together) was 0.53%, but total forest disturbance within protected areas was greater than in non-protected forest (0.66% versus 0.50%, respectively), and so was the annual rate of selective logging (i.e. without clearcuts, 0.37% versus 0.25%, respectively). Our results highlight that monitoring only clearcuts without assessing selective logging might result in significant underestimation of forest disturbance. Also, when timber harvesting is important for the local economy and when protected areas have valuable timber resources that have already been depleted elsewhere, then additional protection may be necessary in order to maintain natural forests within protected areas. We suggest that this is the situation in our study area in Western Siberia right now and is likely the situation in many other parts of the globe as well.

Ecosystem pool of phosphorus (P) was determined as the sum of above-ground vegetation, roots, necromass and soils to 1 m deep in a tropical rain forest in Sabah, Malaysia. Relationships among soil P fractions, acid phosphatase activity and fine-root biomass across soil horizons were also determined to understand P availability. Ecosystem pools of P, and of simultaneously quantified nitrogen (N) and carbon (C) were 3.4, 12 and 370 Mg ha−1, respectively. Only 2.6% of the total ecosystem P was in the above-ground vegetation, contrasting to C (60%) and N (16%). Canopy foliage of dominant tree species showed an extremely high N to P ratio of 31.5, which implied the excessively short supply of P compared with ample N. Soil P primarily consisted of recalcitrant occluded fractions (78–91%) and only 4% was labile. Approximately three-quarters of labile soil P was an organic fraction (Po). The concentration of labile Po did not differ between soil horizons, while both phosphatase activity and fine-root density were the greatest in the topsoil (top 5 cm) and dramatically decreased with depth. This suggests that trees depend on the acquisition of P from the labile Po in the topsoil, despite a greater amount of labile P in the subsoil. Trees with a high foliar N/P ratio may invest N to acquire P from the topsoil by secreting phosphatase that consists of proteins, rather than investing C to extending roots to scavenge P in the subsoil.

Logged forests form an increasingly large proportion of tropical landscapes but disproportionately few studies have studied the impact of forest disturbance, e.g. lightly vs. heavily logged, on tree and seedling communities simultaneously. We sampled all trees (on 1 ha) and all recently germinated seedlings (on 90 m2) in three lightly and three heavily logged sites in each of the following three East African tropical forests: Budongo Forest and Mabira Forest in Uganda and Kakamega Forest in Kenya. We analysed species richness, diversity, abundance and community composition of late- and early-successional trees and seedlings. We recorded no difference in species richness or diversity of late-successional or early-successional trees between lightly and heavily logged sites. However, the abundance of late-successional species was lower in heavily than lightly logged sites. Moreover, there was no difference in species richness or diversity of trees among the three forests. Yet, abundances of late-successional trees were higher in Budongo Forest than in Mabira Forest and Kakamega Forest. Species richness, diversity and abundance of seedlings did not differ between lightly and heavily logged sites. Only the abundance of seedlings of late-successional species differed among the forests with more individuals in Budongo Forest than in Mabira Forest. This was corroborated by non-metric multidimensional scaling (NMDS) showing clear differences in composition of tree and seedling communities among the three forests. Thus, both, the tree and seedling communities differed significantly among the three forests but not between lightly and heavily logged sites.

Trees of the family Dipterocarpaceae dominate the emergent canopy of most lowland rain forests in Asia (Ashton et al. 1988). The family is, therefore, one of the most ecologically important in South-East Asia. Shorea curtisii Dyer ex King is the most common tree species in the hill dipterocarp forests of Peninsular Malaysia (Burgess 1975, Symington 2004), and is considered a key species for the dynamics of such forests. Currently, most Malaysian hill forests are selectively logged. Trees over 50 cm dbh are harvested, and any subsequent harvests depend on the remaining smaller trees. Such selective logging takes no account of seedling regeneration. Hence, subsequent timber harvests rely on trees derived from the seedlings that are already present and future seeds produced by the residual trees (Appanah & Mohd. Rasol 1994). Existing seedlings of S. curtisii in the forest, therefore, play a significant role in the dynamics of the hill forest. However, the conditions that constitute a suitable habitat for S. curtisii seedling establishment and survival remain unknown.

Rates of litterfall over a period of 3 y at one undisturbed site and two sites disturbed by selective harvesting are reported for a tropical rain forest area in North Queensland, Australia. Litterfall over a period of 18 months is also reported for a further undisturbed site in the same area. No significant differences were found in annual litterfall between the sites, with annual litterfall rates ranging from 5.0 to 6.0 t ha−1 y−1. These rates are considerably lower than those reported for other rain forest areas in Australia, and are within the lower ranges recorded for other tropical rain forests. Litterfall was found to be strongly seasonal at all sites with the maximum falls occurring from the end of the dry season to the end of the wet season. The between year variability of the sites was quite low, with the ratio of maximum to minimum production ranging from 1.05 to 1.20. The average percentages of leaves, wood and reproductive material in litterfall were similar at each site. Leaves were the dominant component of litterfall with the average proportion of the total litterfall ranging from 72% to 76% over the study period at each of the four sites. At certain times, however, the fall of wood and reproductive material was quite significant, comprising as much as 71% and 34% of litterfall respectively. A strong negative correlation was found between the fall of leaves and wood at all sites.

This paper introduces studies of nutrient cycling in disturbed and undisturbed rain forest plots in the upper catchment of Birthday Creek, near Paluma, North Queensland. The catchment is underlain by granite and has soils of comparatively low fertility. Differences between unlogged plots and plots disturbed 25 years previously by selective logging are still apparent. Disturbed plots have soils with higher bulk densities and pH, lower CEC, kjeldahl nitrogen and available phosphorus concentrations, and changed species composition. The data suggest that recovery from selective logging is dependent on soil fertility and intensity of disturbance.

Effects of tree species heterogeneity on leaf fall were studied in a primary (4 ha) and in a selectively logged forest plot (2.5 ha) in the Ulu Segama Forest Reserve, Sabah, Malaysia, from April 1988 to December 1989. Leaf fall was collected at 30 sampling points in each plot, and identified to species.

Dipterocarpaceae, Euphorbiaceae, Lauraceae, Fagaceae and Meliaceae are important tree families in both plots with regard to their contribution to total basal area, tree density and annual leaf fall. The total number of tree species was higher in the primary forest plot (267) than in the logged forest plot (218), although the number of climber species was higher in the logged forest (44) than in the primary forest plot (33). The overlap in species composition between the two forest plots was relatively small (49%) compared with that in family composition (88%).

In the primary forest plot, the Dipterocarpaceae contributed 29% of the total basal area and 34% of the annual leaf fall. In the logged forest plot these contributions were much lower, 11% and 15%. The contribution to annual leaf fall made by climbers and pioneer trees was higher in the logged forest plot (34%) than in the primary forest plot (8%).

In the primary forest plot, leaf fall was dominated My large emergent and main canopy trees, mainly dipterocarps, and occurred as regular large peaks. In the logged forest leaf fall was dominated by climbers and many, relatively small trees of pioneer species, such as Macaranga hypoleuca, and was more evenly distributed in time.

To obtain information on density of tiger Panthera tigris in selectively logged forest, a 9-month camera-trapping survey was conducted over elevations of 190–850 m in lowland and hill/upper dipterocarp and lower montane forests in Gunung Basor Forest Reserve, Peninsular Malaysia. Capture-recapture sampling methods were used to estimate tiger population density in the Reserve. The number of individual tigers captured was six. Using the Mh jackknife estimator the average capture probability per sampling occasion was 0.28 and the corresponding estimate of population size 8 ± SE 1.89. The overall probability of photo-capturing a tiger present in the sampled area was 0.75. Using an approach based on distances between photo-captures, a buffer width of 3.22 km and an effectively sampled area of 308 km2 was estimated. This resulted in a density estimate of 2.59 ± SE 0.71 adult tigers per 100 km2. The results indicate that selectively logged forests such as Gunung Basor Forest Reserve have the potential to accommodate a high density of tigers. Decision makers and conservation planners should not therefore perceive selectively logged forests to have limited conservation value. Further research on the ecology of tigers and their prey in selectively logged forests is urgently needed. Such research would enable conservationists to recommend tiger-friendly management guidelines for sustainable forest management and thereby significantly contribute to tiger conservation in Malaysia.

One concern in the ongoing debate over the conservation status of mahogany has been the possibility that selective logging, as a form of negative phenotypic selection, might have led to deterioration in the genetic quality of populations. The incidence and degree of such ‘dysgenic’ effects is discussed, based on a consideration of mahogany logging practices, their expected genetic effects and empirical data on phenotypic selection in forest trees. Loggers have tended to avoid diseased, small, very large and poorly-formed individuals, and consequently logging has tended to increase the proportion of poor quality phenotypes relative to that before logging; in at least some conditions, selection differentials have been strongly negative. However, the upper limit for heritability of logger-selected traits in naturally-regenerated mahogany is probably no more than c. 0.1. Consequently, and assuming relatively extreme but realistic negative selection differentials of 50%, the maximum negative dysgenic response to a single logging-mediated phenotypic selection event is expected to be relatively small, i.e. ≤5%. This expectation is consistent with the empirical information from mahogany and other taxa. The implications of any dysgenic effects depend very much on the use and the future of dysgenically-selected populations. In managed populations, dysgenic effects could be reversed through positive selection. In the case of exploited but currently unmanaged natural populations, dysgenic selection is primarily of importance insofar as it affects fitness. As a threat to mahogany conservation and long-term sustainable production, it is probably insignificant in comparison with other genetic and non-genetic factors.

We used traps baited with fruit to examine how the temporal variation of butterflies within primary forest in Sabah, Borneo differed between species. In addition, we compared patterns of temporal variation in primary and selectively logged forest, and we tested the hypothesis that selective logging has different recorded impacts on species diversity of adults during the wet monsoon period and the drier remaining half of the year. Species of Satyrinae and Morphinae had significantly less-restricted flight periods than did species of Nymphalinae and Charaxinae, which were sampled mainly during the drier season, especially in primary forest. Species diversity of adults was significantly higher during the drier season in primary forest, but did not differ between seasons in logged forest. As a consequence, logging had opposite recorded impacts on diversity during wetter and drier seasons: primary forest had significantly higher diversity than logged forest during the drier season but significantly lower diversity than logged forest during the wetter monsoon season. The results of this study have important implications for the assessment of biodiversity in tropical rain forests, particularly in relation to habitat disturbance: short-term assessments that do not take account of seasonal variation in abundance are likely to produce misleading results, even in regions where the seasonal variation in rainfall is not that great.

Anthropogenic disturbance in Amazonian forests has increased dramatically since the early 1980s and forest disturbance is expected to continue in the early twenty-first century. Logging and conversion to pasture for cattle are two of the largest causes of forest disturbance and destruction. This study examined the distribution and diversity of dung beetles (Coleoptera: Scarabaeidae) in intact forest and under three disturbance regimes (selective logging, clear-cutting and pasture) in a forest tract in southern Pará state, Brazil. Dung beetles were collected using faeces-baited pitfall traps, then identified, measured and weighed. Principal Components Analyses and the Sørensen's Index indicated that the intact and selectively logged areas were similar in terms of species composition but that the pasture areas and clear-cut areas had substantially different groups of species. Beetle size and diversity (as measured by species richness, Shannon index and Simpson's index) were lower in clear-cuts and pasture than in intact forest. The selectively logged forest was no less diverse than intact forest, and beetles were the same size or larger than those in intact forest. Total beetle biomass, however, was highest in the pasture due to the abundance of small-bodied beetles in this habitat. While the fact that selective logging has a relatively minor impact on the dung beetle community is heartening, the projected increase in the amount of highly disturbed landscape in Amazonia is expected to have a severe impact on dung beetle biodiversity in the region.

Surface fires have recently become a widespread pantropical phenomenon that could trigger revolutionary changes in the structure and functioning of tropical forests and result in a catastrophic impoverishment of the vertebrate fauna. Here we describe the short- and medium-term responses of bird and mammal assemblages to an unprecedented wildfire that scorched the understorey of 1,100 km2 of forest in the Arapiuns-Maró river basin of central Brazilian Amazonia. Fire-induced mortality in the aftermath of this burn was high for a wide range of plant and animal populations monitored. This included an average of 36% of all large trees in eight quarter-hectare plots sampled in burnt forest, which dramatically altered the post-burn understorey light environment. The Arapiuns wildfire also resulted in significant socioeconomic costs to local forest dwellers, namely crop losses and the decimation of many forest resources, including key game vertebrate species pursued by subsistence hunters, vines and woody lianas, and many fruit species. The conservation prospects of the vertebrate fauna in fire-prone Amazonian forests are discussed with respect to the increasingly more frequent and severe El Niño-mediated dry seasons.

The diurnal primate community of the Korup area of south-west Cameroon is rich in species and high in endemism. Two years monitoring in the Support Zone around Korup National Park have shown that, although all species of the original community are still present, Preuss' red colobus and drill, which were considered to be threatened in the early 1990s, have declined further and are probably facing local extinction. Densities of the crowned monkey also seem to have declined. Only mona and putty-nosed monkeys have an expanded distribution, and densities that are within the range of those reported from previous studies in the region. Although hunting is the most important cause of these declines, logging also appears to be having a detrimental effect. In logged forest group densities of chimpanzee, red-capped mangabey, mona monkey and red-eared monkey decreased between the two survey years, whilst remaining constant or increasing in unlogged forest. The frequency of associations of guenon species did not differ between logged and unlogged study sites, but encounters of associations of all four guenon species were only found in unlogged forest. We strongly recommend enforcement of anti-poaching activities inside the Korup National Park, and establishment of wildlife management in the Support Zone, as only a combined strategy can successfully guarantee the persistence of the wildlife of the region.

Maintenance of high plant diversity in tropical rain forests has been hypothesized to be related to intense seed predation, and studies have shown that the impact of seed-eaters varies according to seed size, forest type and level of disturbance. The hypothesis that seed survival and seedling recruitment depending on seed size, are related to forest type and the intensity of harvesting and stand refinement was therefore tested at Paracou, French Guiana, for three animal-dispersed tree species. Two forest areas, corresponding to two forest types, were selected based on the occurrence of a dominant species, Eperua falcata (Caesalpiniaceae). Two factors were tested: forest type (E. falcata-rich and E. falcata-poor) and level of harvesting (unlogged, low intensity of logging, low intensity of logging and thinning liberation by tree-poison girdling) within each forest type. Overall, there was no effect of species nor of logging treatment within forest type after 6 wk. There was only a significant effect of forest type on seed survival in the large-seeded Carapa procera, a rodent-dispersed species in the Meliaceae. In the two medium-sized seed species, Pradosia cochlearia and Manilkara bidentata, two frugivore-dispersed Sapotaceae, the effect of treatment was overall significant but was also highly variable between plots within treatments. After 1 y, C. procera showed little seedling recruitment due to low seed removal and dispersal, and high seed-seedling predation under all conditions. Neither forest type, nor treatment nested within forest type, affected seedling recruitment in P. cochlearia whereas M. bidentata seedlings were favoured in unlogged conditions at the E. falcata-poor forest type. These results suggest that species characteristics (such as seed size and palatability), or local tree diversity and resources for granivores select for contrasting patterns in tree recruitment between forest type in the rodent-dispersed tree species, and these interact with level of tree harvesting and stand refinement in the other frugivore-dispersed tree species.

Woodpeckers (Picidae) are a group of birds particularly sensitive to logging and deforestation because they nest in cavities located in large trees and often forage on large trunks or standing dead trees. The diverse woodpecker community of lowland dipterocarp forests in Peninsular Malaysia was investigated in a forest selectively logged 40 y ago and in adjacent primary forest at Pasoh Forest Reserve (PFR). Line transects were conducted at dawn and dusk in each forest type to document potential differences in the woodpecker communities in logged vs. unlogged forest. A total of 121 woodpeckers were recorded along transects, including 14 of the 15 species known to occur at PFR. Eleven species were encountered in logged forest, 12 species were encountered in primary forest, and nine species were found at both sites. A significant difference in the overall woodpecker community between the two forest types was found. Of the most common species, Meiglyptes tristis, Reinwardtipicus validus and Dryocopus javensis were significantly more common in primary forest. Only one species, Picus mentalis, was significantly more abundant in logged forest. Possible causes for the differences observed are discussed.

The Leuser Ecosystem, northern Sumatra, Indonesia, contains the world's largest orang-utan Pongo pygmaeus population. We examine the consequences of the recent wave of forest conversion, and legal and illegal logging, on orang-utan numbers in the Leuser Ecosystem. We review density variation inside the Leuser Ecosystem and its causes, and the consequences of selective logging, exhaustive logging and clear-felling for habitat conversion on orang-utan densities. The analysis of the orang-utan's decline is based on information on forest loss, logging intensity, and the delineation of logging concessions and legal changes in land use status. The results indicate a very rapid decline, by c. 45 per cent, from c.. 12,000 in early 1993, over a 6- to 7-year period. During 1998 and 1999, losses occurred at a rate of about 1000 orang-utans per year. At this rate, further losses in the near future are expected to put the survival of Leuser's orang-utans in serious doubt.

The nutrient contents and accessions in litterfall over a period of 3 y are reported for undisturbed areas and at two sites disturbed by selective harvesting in tropical rain forest in North Queensland, Australia. Mean concentrations (mg g&supminus1; dry weight) of nutrients in litterfall ranged from 10 to 12 for nitrogen; 0.33 to 0.43 for phosphorus; 3.6 to 4.3 for potassium; 6.0 to 10.5 for calcium; and 1.7 to 2.6 for magnesium. These concentrations are in the middle to lower part of the spectrum of values recorded for tropical forests. Accessions of nutrients in litterfall (kg ha&supminus1; y&supminus1;) ranged from 59 to 64 N; 1.9 to 2.4 P; 20 to 24 K; 34 to 63 Ca; and 9 to 16 Mg. These rates, particularly for N and P, are among the lowest recorded for tropical forests. There were no consistent between-site differences in total nutrient accessions in small litterfall. In terms of the contribution of litterfall to the accessions of nutrients to the forest floor, this suggests that the logged sites have recovered from the effects of selective harvesting within 25 y. Nutrient accessions at each site were distinctly seasonal, with maximum accessions occurring in the late dry season to late in the wet season. Leaf-fall accounted for the largest proportion of nutrient accessions over the study period, although at certain times accessions in both reproductive material and wood were significant. A cyclone which crossed the coast near the study sites resulted in large nutrient accessions over a short period but had little effect on the total annual accession. A comparison with previous studies of litterfall in Australian tropical rainforests indicates that nutrient return in litterfall is directly related to soil fertility.