Tree communities of different aged logged areas in an Afrotropical rainforest

Predicting the recovery processes in tree communities after logging is critical when developing conservation strategies. We assessed the patterns in tree communities in logged and primary forests in Kibale National Park, Uganda, representing 9‐ to 19‐year‐old clear‐cuts of former conifer plantations, 42‐ to 43‐year‐old logged forests and primary forests. Species density and diversity were lower and dominance higher in the 9‐ to 19‐year‐old forests compared to the 42‐ to 43‐year‐old forests or primary forests. The tree species density, diversity and dominance of 42‐ to 43‐year‐old forests did not differ significantly from primary forests. However, they had a lower stem density, and higher cover of Acanthus pubescens, a shrub known to arrest the succession in Kibale. The tree community compositions of 9‐ to 19‐year‐old, 42‐ to 43‐year‐old and primary forests differed from each other. A large group of tree species (21) were primary forest indicators, that is, they were either missing or relatively rare in logged forests. The results of this study show that even after four decades of natural recovery, logged Afrotropical forests can still be distinguished from primary forests in their tree community compositions, emphasizing the slow community recovery and the important role of primary forests when preserving the tree communities in tropical rainforests.     

Effects of Logging and Oil Palm Expansion on Stream Frog Communities on Borneo,Southeast Asia

The conversion of tropical rain forests to oil palm plantations is a major threat to Southeast Asia's rich biodiversity. Fostering forest species communities in secondary forests, agroforestry systems, and plantations is therefore increasingly becoming a conservation focus. This study uses standardized transect‐based sampling to compare species richness, density and community composition of stream anuran assemblages among primary forests, repeatedly logged forests and oil palm plantations in northern Borneo. In primary forest streams, we recorded an average of 19 frog species, compared to 15 species in logged forests and 11 species in oil palm plantation streams. However, the high percentage of canopy cover above the plantation streams mitigated this loss to some extent. This study corroborates numerous studies that oil palm plantations have mainly negative effects on the region's biodiversity. However, our results also demonstrate the high conservation value of logged forests for Bornean stream‐dependent anurans. We conclude that palm plantations have a largely unused potential to promote regional anuran biodiversity.     

Structure,composition and diversity of plant communities in FSC-certified,selectively logged forests of different ages compared to primary rain forest

The impact of logging on plant communities was studied in forest that has been logged selectively 1, 5 and 10 years previously (following a certified procedure): diversity was compared with that of primary rain forest in the Berau region of East Kalimantan, Indonesia. Four sets of 20 transects located within an area of 6 ha were sampled for all trees, saplings and seedlings, and records were made of topographic position, structure, composition and species diversity. There was a high level of floristic similarity between primary forests at the study sites compared to primary forest elsewhere in Kalimantan. The impact of logging is therefore likely to be the most important factor determining any differences between the plant communities of the selectively logged and primary forest sites. We found differences in species composition and abundance of most plants between selectively logged and primary forest. Overall, stem densities of trees in the primary forest were higher than in the three selectively logged forest sites. Stem densities of saplings were equivalent in all four forests. Seedling stem densities were higher in the forest site logged 10 years previously than in primary forest. Our results showed that the forests logged selectively under certified regimes still have a high plant diversity, possibly indicating that biodiversity values may be conserved by following certification procedures.     

Differences in the Effects of Selective Logging on Amphibian Assemblages in Three West African Forest Types

Making generalizations about the impact of commercial selective logging on biodiversity has so far remained elusive. Species responses to logging depend on a number of factors, many of which have not been studied in detail. These factors may include the natural forest conditions (forest types) under which logging impacts are investigated; but this question has so far remained unexamined. In a large‐scale replicate study we aimed at clarifying the relationship between logging and forest types on leaf litter frogs. We contrast three distinct and naturally occurring forest types, including wet evergreen, moist evergreen and semi‐deciduous forests. Selectively logged sites were compared with primary forest sites for each forest type. We found that the response of frog communities to logging varies in different forest types. In the wet evergreen forest, richness was higher in logged forest than primary forest, while diversity measures were not different between logged and primary forest habitats. In the moist evergreen, richness and diversity were higher in selectively logged areas compared with primary forest habitats. In the semi‐deciduous, logged forests were characterized by drastic loss of forest specialists, reduced richness, and diversity. These results indicate that the net effect of logging varies with respect to forest type. Forest types that are characterized by adverse climatic conditions (i.e., low rainfall and protracted dry seasons) are more likely to produce negative effects on leaf litter anuran communities. For comparisons of the impact of logging on species to be effective, future research must endeavor to include details of forest type.     

Impacts of logging and conversion of rainforest to oil palm on the functional diversity of birds in Sundaland

Commercial selective logging and the conversion of primary and degraded forests to agriculture are the biggest threats to tropical biodiversity. Our understanding of the impacts of these disturbances and the resulting local extinctions on the functional roles performed by the remaining species is limited. We address this issue by examining functional diversity (FD), which quantifies a range of traits that affect a species' ecological role in a community as a single continuous metric. We calculated FD for birds across a gradient of disturbance from primary forest through intensively logged forest to oil palm plantations on previously forested land in Borneo, Southeast Asia, a hotspot of imperilled biodiversity. Logged rainforest retained similar levels of FD to unlogged rainforest, even after two logging rotations, but the conversion of logged forest to oil palm resulted in dramatic reductions in FD. The few remaining species in oil palm filled a disproportionately wide range of functional roles but showed very little clustering in terms of functional traits, suggesting that any further extinctions from oil palm would reduce FD even further. Determining the extent to which the changes we recorded were due to under‐utilization of resources within oil palm or a reduction in the resources present is an important next step. Nonetheless our study improves our understanding of the stability and resilience of functional diversity in these ecosystems and of the implications of land‐use changes for ecosystem functioning.     

Roles of fragmented and logged forests for bird communities in industrial Acacia mangium plantations in Indonesia

Industrial timber plantations severely impact biodiversity in Southeast Asia. Forest fragments survive within plantations, but their conservation value in highly deforested landscapes in Southeast Asia is poorly understood. In this study, we compared bird assemblages in acacia plantations and fragmented forests in South Sumatra to evaluate each habitat’s potential conservation value. To clarify the impact of habitat change, we also analyzed the response of feeding guild composition. Five habitat types were studied: large logged forest (LLF), burnt logged forest (BLF), remnant logged forest (RLF), 4-year-old acacia plantation (AP4), and 1-year-old acacia plantation (AP1). Estimated species richness (Chao 2) was highest in LLF then AP4 and BLF, while AP1 and RLF had lower estimated species richness. Community composition was roughly divided into two groups by non-metric multidimensional scaling ordination: acacia plantation and logged forest. Sallying substrate-gleaning insectivores, such as drongos, broadbills, and some flycatchers, were restricted to LLF, whereas acacia plantation hosted many terrestrial frugivores, such as doves. Although fragmented forests in our study site lacked several common tropical forest species, these fragments provide an important habitat for some sallying and terrestrial insectivores. A network of small riparian remnant forests could be a complementary habitat for some species, while the conservation value of burnt forest might be low. In conclusion, the highly fragmented forests in plantations are suboptimal habitats for birds but are still very important, because large primary forest blocks have been nearly lost in the surrounding landscape.     

Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?

Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.     

Effects of disturbances on scuttle flies (Diptera: Phoridae) in Pine Forests

I investigated the ecological consequences of disturbances (anthropogenic and natural) on the scuttle fly communities in four large Pine Forests in Poland. I used data on 17,547 male individuals representing 183 species. Communities found in pine plantations (established in clear-cut areas) and in differently treated post-windstorm (with windthrow logs being left or removed) were less diverse than those found in old-growth forest. The communities recorded in the same habitat types in different forest complexes (ca. 300 km apart) were found to display greater similarity than those recorded on adjacent plots in a given forest (ca. 1 km apart), but covering different habitats. The species-specific preference for habitats after disturbances (clear-cuts and post-windstorm areas) was highly correlated between the forests. The abundance of the species with saprophagous larvae was distinctly higher in the disturbed areas than in the old-growth stands. Also, the body length of the scuttle flies was significantly related to their preference for disturbed or undisturbed habitats: smaller species preferred clear-cuts and post-windstorm areas, whereas larger species were related to intact stands.     

Effects of Historical Selective Logging on Anuran Communities in a Wet Evergreen Forest,South India

Vast areas of tropical evergreen forests have been selectively logged in the past, and many areas continue to be logged. The impacts of such logging on amphibians are poorly understood. I examined the response of anuran communities to historical selective logging in a wet evergreen forest in south India. Anuran assemblages in unlogged forest were compared with assemblages in selectively logged forest. Forty 10 m × 10 m quadrats in forest, riparian zones, and streams of unlogged and selectively logged forests were searched at night for anurans. Species richness did not appear to be affected by logging. However, anuran density varied significantly and was 42 percent lower in selectively logged forests compared to unlogged forests. Anuran densities also varied significantly across microhabitats, with highest densities in streams of both selectively logged and unlogged forests. Patterns of niche overlap varied with selective logging as niche breadth either expanded, contracted, or remained neutral for different species. Ordination analysis explained 95 percent of the variation in species assemblage across selectively logged and unlogged forests. The assemblage in selectively logged forest was nested within unlogged forest. Among the habitat characteristics, litter thickness and water depth had the highest influence on the assemblage. This was followed by litter/water temperature, air temperature, and lastly relative humidity. It appears that species richness and composition of anurans in selectively logged forests is converging with unlogged forests, but the effects of historical logging seem to persist on anuran densities and their niche characteristics even ca 40 yr since logging ceased.     

An Evaluation of the Contribution of Cultivated Allspice (<Emphasis Type="Italic">Pimenta Dioca</Emphasis>) to Vertebrate Biodiversity Conservation in Nicaragua

Tropical deforestation has emerged as one of the most important conservation challenges of our time, both because of the high species diversity and rates of endemism of tropical forests, and because of the rapid rate at which this process is proceeding. Recent studies indicate that areas of low-intensity agroforestry have similar levels of vertebrate diversity as some primary habitats, leading some researchers and conservationists to conclude that this type of commodity production could contribute to the conservation of biodiversity. We compared the composition of bird, mammal and herpetofaunal communities in primary forest, secondary forest, and pasture—and within the allspice productive systems that have replaced pasture. We found that mammal species richness was higher in primary forest than all other habitats; however for resident and migrant birds, amphibians and reptiles, species richness was similar between primary forest and the other habitats. Despite similarities in overall numbers of species, there were numerous species that were encountered only in primary habitats. We conclude that the cultivation of allspice in a mixed productive system can offset some of the losses to biodiversity; however it should be complemented by the establishment and maintenance of protected areas to accommodate populations of primary forest specialists that are unable to persist in altered habitats.     

Butterfly Community Composition Across a Successional Gradient in a Human‐disturbed Afro‐tropical Rain Forest

Knowledge of the recovery of insect communities after forest disturbance in tropical Africa is very limited. Here, fruit‐feeding butterflies in a tropical rain forest at Kibale National Park, Uganda, were used as a model system to uncover how, and how fast, insect communities recover after forest disturbance. We trapped butterflies monthly along a successional gradient for one year. Traps were placed in intact primary forest compartments, heavily logged forest compartments with and without arboricide treatment approximately 43 years ago, and in conifer‐clearcut compartments, ranging from 9 to 19 years of age. The species richness, total abundance, diversity, dominance, and similarity of the community composition of butterflies in the eight compartments were compared with uni‐ and multivariate statistics. A total of 16,728 individuals representing 88 species were trapped during the study. Butterfly species richness, abundance, and diversity did not show an increasing trend along the successional gradient but species richness and abundance peaked at intermediate stages. There was monthly variation in species richness, abundance, diversity and composition. Butterfly community structure differed significantly among the eight successional stages and only a marginal directional change along the successional gradient emerged. The greatest number of indicator species and intact forest interior specialists were found in one of the primary forests. Our results show that forest disturbance has a long‐term impact on the recovery of butterfly species composition, emphasizing the value of intact primary forests for butterfly conservation.     

Effects of selective logging on the arboreal ants of a Bornean rainforest

We examined the effect of selective logging and corresponding forest canopy loss on arboreal ant diversity in a tropical rainforest. Arboreal ants were collected from an unlogged forest plot and from forest plots selectively logged 14 years and 24 years earlier in Danum Valley, Sabah, Malaysia, using a canopy fogging method. Selective logging was associated with a significant decrease in canopy cover and an increase in understory vegetation density relative to unlogged forest. Our study showed that selective logging in primary forest might not dramatically decrease total species number and overall abundance of arboreal ants; however, it may influence the species composition and dominance structure of the ant community, accompanied by an increase in abundance of shrub‐layer species and trophobiotic species. In view of the results of this study, management techniques that minimize logging impact on understory vegetation structure are likely to help maintain the conservation value of logged forests for arboreal ants. Our results also suggest that accurate assessment of the impacts on biodiversity should not be based only on measurement of species number and overall abundance, but also on analysis of species composition and community structure.     

Birds in the matrix: the role of agriculture in avian conservation in the Taita Hills,Kenya

Agricultural conversion of tropical forests is a major driver of biodiversity loss. Slowing rates of deforestation is a conservation priority, but it is also useful to consider how species diversity is retained across the agricultural matrix. Here, we assess how bird diversity varies in relation to land use in the Taita Hills, Kenya. We used point counts to survey birds along a land‐use gradient that included primary forest, secondary vegetation, agroforest, timber plantation and cropland. We found that the agricultural matrix supports an abundant and diverse bird community with high levels of species turnover, but that forest specialists are confined predominantly to primary forest, with the matrix dominated by forest visitors. Ordination analyses showed that representation of forest specialists decreases with distance from primary forest. With the exception of forest generalists, bird abundance and diversity are lowest in timber plantations. Contrary to expectation, we found feeding guilds at similar abundances in all land‐use types. We conclude that whilst the agricultural matrix, and agroforest in particular, makes a strong contribution to observed bird diversity at the landscape scale, intact primary forest is essential for maintaining this diversity, especially amongst species of conservation concern.     

Loss of biodiversity and shifts in aboveground biomass drivers in tropical rainforests with different disturbance histories

Tropical forests account for more than half of the global carbon forest stock and much of the biological diversity on Earth. However, disturbances such as deforestation and forest degradation threaten the maintenance of these ecosystem services. This study aimed to understand how different disturbance histories affect the forest stand biomass, as well as species and functional diversity, and to what extent these differences can change the relationships between biomass and their drivers. We used data from forests with clear-cut and selectively logged disturbance histories, and from old-growth forests, situated in the Brazilian Atlantic forest. Forests with logging disturbances showed significant losses in their aboveground biomass compared to those of old-growth forests (50% loss in selectively logged forests and 80% loss in clear-cut forests). Interestingly, only clear-cut secondary forests showed differences in species and functional diversity, and were dominated by species with acquisitive trait values, commonly found early in succession. Shifts in stand biomass drivers were observed in selectively logged forests. The mass-ratio hypothesis (mainly through the functional trait of maximum height) was the most important biomass driver in clear-cut secondary and old-growth forests, whereas the importance of the niche complementarity hypothesis (through functional richness and dispersion) was higher in selectively logged forests. Our study highlights that disturbance histories can affect forest aboveground biomass and its drivers. Moreover, our results reinforce the need for conservation of intact forests but highlight the importance of including degraded forests in conservation mechanisms based in carbon stocks, as these forests retain high values of species and functional diversities that are crucial to biomass and consequently carbon stock acquisition.     

The avifauna 23 years after logging in Kibale National park, Uganda

The bird fauna of logged and unlogged forest in Kibale National Park, western Uganda were studied and comparisons made. Species diversity and richness were higher in the logged areas. A single species, the Yellow-whiskered Greenbul Andropadus latirostris dominated in the logged compartment. However, the majority of individual birds found in the logged forest were generalist or forest-edge species. Over 84% of the forest interior specialist species that occurred in primary forest had recolonized or persisted in the logged forest; however, there were seven out of 48 understorey forest specialists that had not done so. Although there was moderate species overlap between the two habitats, the logged forest compartment had not fully recovered from logging after 23 years.     

Dead trees left in clear-cuts benefit saproxylic Coleoptera adapted to natural disturbances in boreal forest

Forest management alters the pattern of forest dynamics from that in natural conditions in the boreal region. In order to examine how certain forestry measures matching natural dynamics affect forest insects, we compared assemblages of saproxylic Coleoptera on dead, standing birch trunks left behind in eight clear-cut areas with corresponding assemblages in seven mature forests in southern and eastern Finland. We used trunk-window traps for sampling. Distinct beetle assemblages were associated with the different habitats. Median numbers of species or specimens caught did not differ between closed forests and clear-cuts, but individual beetle species occurred unevenly among the habitats. Several beetle species associated with open forest habitat, e.g. burned forests or storm-damage areas, including species regarded as threatened in Finland, were found almost exclusively, in clear-cuts. Correspondingly, a number of beetle species occurring frequently in closed forests were not found in clear-cuts. We conclude that dead trunks left in the clear-cut areas may host not only generalist saproxylic species but also many beetle species specialized to warm, sun-exposed environments, and such species may not be able to survive in closed forests. Management measures matching suppressed natural disturbances are found useful in preserving diversity in managed forests.     

Ferns,frogs, lizards,birds and bats in forest fragments and shade cacao plantations in two contrasting landscapes in the Atlantic forest,Brazil

The traditional shade cacao plantations (cabrucas) of southern Bahia, Brazil, are biologically rich habitats, encompassing many forest-dwelling species. However, a critical question for the conservation management of this specific region, and the highly fragmented Atlantic forest in general, is to what extent the conservation value of cabrucas relies on the presence of primary forest habitat in the landscape. We investigated the relative importance of cabrucas and forests for the conservation of five diverse biological groups (ferns, frogs, lizards, birds and bats) in two contrasting landscapes in southern Bahia, one dominated by forest with some interspersed cabrucas, and one dominated by cabrucas with interspersed forest fragments. The community structure (richness, abundance and diversity) of all biological groups differed between cabrucas and forests, although these differences varied among groups. A high number of forest species was found in the cabrucas. However, there were pronounced differences between the two landscapes with regard to the ability of cabrucas to maintain species richness. Irrespective of the biological group considered, cabrucas located in the landscape with few and small forest fragments supported impoverished assemblages compared to cabrucas located in the landscape with high forest cover. This suggests that a greater extent of native forest in the landscape positively influences the species richness of cabrucas. In the landscape with few small forest fragments interspersed into extensive areas of shade cacao plantations, the beta diversity of birds was higher than in the more forested landscape, suggesting that forest specialist species that rarely ventured into cabrucas were randomly lost from the fragments. These results stress both the importance and the vulnerability of the small forest patches remaining in landscapes dominated by shade plantations. They also point to the need to preserve sufficient areas of primary habitat even in landscapes where land use practices are generally favorable to the conservation of biodiversity.     

Logging and indigenous hunting impacts on persistence of large Neotropical animals

Areas allocated for industrial logging and community‐owned forests account for over 50% of all remaining tropical forests. Landscape‐scale conservation strategies that include these forests are expected to have substantial benefits for biodiversity, especially for large mammals and birds that require extensive habitat but that are susceptible to extirpation due to synergies between logging and hunting. In addition, their responses to logging alone are poorly understood due to their cryptic behavior and low densities. In this study, we assessed the effects of logging and hunting on detection and occupancy rates of large vertebrates in a multiple‐use forest on the Guiana Shield. Our study site was certified as being responsibly managed for timber production and indigenous communities are legally guaranteed use‐rights to the forest. We coupled camera‐trap data for wildlife detection with a spatially explicit dataset on indigenous hunting. A multi‐species occupancy model found a weak positive effect of logging on occupancy and detection rates, while hunting had a weak negative effect. Model predictions of species richness were also higher in logged forest sites compared to unlogged forest sites. Density estimates for jaguars and ocelots in our multiple‐use area were similar to estimates reported for fully protected areas. Involvement of local communities in forest management, control of forest access, and nesting production forests in a landscape that includes protected areas seemed important for these positive biodiversity outcomes. The maintenance of vertebrate species bodes well for both biodiversity and the humans that depend on multiple‐use forests.     

Macromoth community structure along a 95-year post-harvest chronosequence in managed forests of northwest Washington State (U.S.A.), with comparison to old growth forest communities

1. The effects of timber harvest in the moist coniferous forests of western North America are not well documented for ecologically important arthropods such as moths.
2. We assessed the response of macromoth community structure (abundance, sample size-corrected estimates of species richness and diversity, and overall community composition) to time since deforestation at 20 previously logged sites (1–95 years post-harvest), and compared the macromoth communities at these stands to four old growth stands.
3. As stand age increased following timber harvest, the number of macromoths captured in ultraviolet light traps increased and the relative abundance of dietary generalists declined, but sample size-corrected estimates of species richness and diversity did not vary. Macromoth community composition of the youngest stands (<10 years post-harvest) differed markedly from each other but converged soon thereafter.
4. Macromoth communities at old growth sites featured higher capture rates, lower dominance by dietary generalists, and higher sample size-corrected estimates of species richness and diversity than at previously logged sites. Community composition profiles for old growth sites differed from all previously logged sites, but the differences were subtle except in comparison to the youngest logged sites. None of the 188 species we sampled were old growth specialists.
5. Our results reveal dramatic initial impacts of deforestation on macromoth communities in moist coniferous forests of western North America. Such effects are largely reversed within two decades post-harvest but some effects persist for at least 95-years following logging.

     

Mass–abundance scaling in avian communities is maintained after tropical selective logging

1. Selective logging dominates forested landscapes across the tropics. Despite the structural damage incurred, selectively logged forests typically retain more biodiversity than other forest disturbances. Most logging impact studies consider conventional metrics, like species richness, but these can conceal subtle biodiversity impacts. The mass–abundance relationship is an integral feature of ecological communities, describing the negative relationship between body mass and population abundance, where, in a system without anthropogenic influence, larger species are less abundant due to higher energy requirements. Changes in this relationship can indicate community structure and function changes.
2. We investigated the impacts of selective logging on the mass–abundance scaling of avian communities by conducting a meta‐analysis to examine its pantropical trend. We divide our analysis between studies using mist netting, sampling the understory avian community, and point counts, sampling the entire community.
3. Across 19 mist‐netting studies, we found no consistent effects of selective logging on mass–abundance scaling relative to primary forests, except for the omnivore guild where there were fewer larger‐bodied species after logging. In eleven point‐count studies, we found a more negative relationship in the whole community after logging, likely driven by the frugivore guild, showing a similar pattern.
4. Limited effects of logging on mass–abundance scaling may suggest high species turnover in logged communities, with like‐for‐like replacement of lost species with similar‐sized species. The increased negative mass–abundance relationship found in some logged communities could result from resource depletion, density compensation, or increased hunting; potentially indicating downstream impacts on ecosystem functions.
5. Synthesis and applications. Our results suggest that size distributions of avian communities in logged forests are relatively robust to disturbance, potentially maintaining ecosystem processes in these forests, thus underscoring the high conservation value of logged tropical forests, indicating an urgent need to focus on their protection from further degradation and deforestation.