South East Asia has the highest rate of lowland forest loss of any tropical region, with logging and deforestation for conversion to plantation agriculture being flagged as the most urgent threats. ...Detecting and mapping logging impacts on forest structure is a primary conservation concern, as these impacts feed through to changes in biodiversity and ecosystem functions. Here, we test whether high-spatial resolution satellite remote sensing can be used to map the responses of aboveground live tree biomass (AGB), canopy leaf area index (LAI) and fractional vegetation cover (FCover) to selective logging and deforestation in Malaysian Borneo. We measured these attributes in permanent vegetation plots in rainforest and oil palm plantations across the degradation landscape of the Stability of Altered Forest Ecosystems project. We found significant mathematical relationships between field-measured structure and satellite-derived spectral and texture information, explaining up to 62% of variation in biophysical structure across forest and oil palm plots. These relationships held at different aggregation levels from plots to forest disturbance types and oil palms allowing us to map aboveground biomass and canopy structure across the degradation landscape. The maps reveal considerable spatial variation in the impacts of previous logging, a pattern that was less clear when considering field data alone. Up-scaled maps revealed a pronounced decline in aboveground live tree biomass with increasing disturbance, impacts which are also clearly visible in the field data even a decade after logging. Field data demonstrate a rapid recovery in forest canopy structure with the canopy recovering to pre-disturbance levels a decade after logging. Yet, up-scaled maps show that both LAI and FCover are still reduced in logged compared to primary forest stands and markedly lower in oil palm stands. While uncertainties remain, these maps can now be utilised to identify conservation win–wins, especially when combining them with ongoing biodiversity surveys and measurements of carbon sequestration, hydrological cycles and microclimate.
•Map degradation of forests in Borneo based on biophysical attributes•Linking RapidEye-derived reflectance and texture data to field measured structure•Beta-logistic regression models explained up to 62% of structure variation.•Up-scaled maps reveal high spatial variation in the impacts of previous logging.•Maps will be utilised to identify high-conservation-value forests.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
1. The impacts of habitat disturbance on biodiversity within tropical forests are an area of current concern but are poorly understood and difficult to predict. This is due in part to a poor ...understanding of how species respond to natural variation in environmental conditions within primary forest and how these conditions alter following anthropogenic disturbance. Within this context, the main aim of this study was to test the hypothesis that the gap and shade preferences of fruit-feeding butterflies in primary forest in northern Borneo can be used to predict species' responses to selective logging and thus explain changes in diversity and geographical distinctness in relation to habitat disturbance. 2. Overall, there was little difference in butterfly diversity between primary forest and forest that had been selectively logged 10-12 years previously. In contrast, there were marked differences in the composition of the butterfly assemblages in the two habitats, which were strongly associated with species' gap preferences and geographical distributions. In Satyrinae and Morphinae, those species with higher shade preferences and narrower geographical distributions were most adversely affected by logging, whereas cosmopolitan species with high light preferences benefited from logging. In Nymphalinae and Charaxinae the opposite was observed: those species with wider geographical distributions were adversely affected and those species with relatively restricted distributions were more common in logged forest. 3. These changes in butterfly assemblages were associated with changes in vegetation structure following selective logging, which resulted in much lower habitat heterogeneity with less dense shade and fewer open gaps in logged forest. Areas of dense shade, which were more common in unlogged forest, supported species of Satyrinae and Morphinae with restricted geographical distributions, whereas open gaps, which were also more common in unlogged forest, attracted widespread species of Nymphalinae and Charaxinae. These butterfly-habitat associations in primary forest explain the opposite responses of the two groups of butterflies to selective logging. 4. Synthesis and applications. This study highlights the need to sample at a sufficiently large spatial scale to account for impacts of disturbance on heterogeneity in forest environments. It also demonstrates how understanding the responses of species to natural variation in environmental conditions within undisturbed forest is crucial to interpreting responses of species to anthropogenic habitat modification. The results further indicate that selectively logged forests can make an important contribution to the conservation of tropical biodiversity, provided that they are managed in a way that maintains environmental heterogeneity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
1. Widespread and rapid losses of tropical rain forests have made understanding the responses of species to rain forest fragmentation an area of major concern. In this study we examined the impacts ...of habitat fragmentation on the species richness and faunal composition of butterflies in tropical rain forests in Sabah, Borneo. We analysed patterns of both α- and β-diversity to assess the relative importance of differences in patch size, isolation and vegetation structure on the diversity and similarity of species assemblages. We used additive partitioning to assess the relative contributions of intact forest and forest remnants to overall species richness at a landscape scale and we examined which traits of species best predicted their responses to fragmentation. 2. Species richness and diversity in rain forest remnants was significantly positively related to remnant size and significantly negatively related to isolation, in keeping with theories of island biogeography. Species assemblages at different sites were significantly nested, with those species most adversely affected by forest fragmentation having a narrow range of larval host-plants and, to a lesser extent, being large-bodied. No species endemic to Borneo was recorded in forest remnants smaller than 4000 ha, but even the smallest remnant (120 ha) supported species with geographical distributions confined within Sundaland (West Malaysia and the islands of the Sunda Shelf). 3. Although assemblages were significantly nested, they departed substantially from perfect nestedness, with some species recorded only or predominantly in small, relatively depauperate remnants. As a result there was substantial β-diversity among sites, which was related to variation in both fragment size and vegetation structure. At the landscape scale, diversity within sites was less than that between sites, and the majority of the diversity between sites was related to variation in fragment size. 4. Synthesis and applications. Substantial diversity was added to the assemblage of butterflies in Bornean rain forests by virtue of species differences among fragments, which were related mainly to differences in patch size and vegetation structure. The data reported indicate that, despite having lower species richness, relatively small and isolated remnants of rain forest make a substantial contribution to regional diversity. Small isolated forest remnants are generally accorded low conservation status and given little protection, with the result that they often disappear over time because of continued anthropogenic disturbance. The results of this study indicate that the conservation value of small remnants of forest, in particular their contribution to environmental heterogeneity, should not be overlooked.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The demand for timber products is facilitating the degradation and opening up of large areas of intact habitats rich in biodiversity. Logging creates an extensive network of access roads within the ...forest, yet these are commonly ignored or excluded when assessing impacts of logging on forest biodiversity. Here we determine the impact of these roads on the overall condition of selectively logged forests in Borneo, Southeast Asia. Focusing on dung beetles along >40km logging roads we determine: (i) the magnitude and extent of edge effects alongside logging roads; (ii) whether vegetation characteristics can explain patterns in dung beetle communities, and; (iii) how the inclusion of road edge forest impacts dung beetle assemblages within the overall logged landscape. We found that while vegetation structure was significantly affected up to 34m from the road edge, impacts on dung beetle communities penetrated much further and were discernible up to 170m into the forest interior. We found larger species and particularly tunnelling species responded more than other functional groups which were also influenced by micro-habitat variation. We provide important new insights into the long-term ecological impacts of tropical logging. We also support calls for improved logging road design both during and after timber extraction to conserve more effectively biodiversity in production forests, for instance, by considering the minimum volume of timber, per unit length of logging road needed to justify road construction. In particular, we suggest that governments and certification bodies need to highlight more clearly the biodiversity and environmental impacts of logging roads.
•Distinct edge effects along roads penetrate >100m into the logged forest interior.•Vegetation changes however, differed within a maximum of 34m of the road edge.•Large diurnal, and tunnelling dung beetles are affected more by proximity to roads.•Micro-habitat variations shown to influence large tunnelling species.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A key challenge in the study of mutualism is to understand the mechanisms that prevent cheating. In some systems, host retaliation against cheaters prevents the breakdown of cooperation. Here, we ...focus on the converse of this demonstration, and ask whether hosts that fail to retaliate are commonly inhabited by cheaters. We do so using the classic ant-plant interaction, in which plants provide ant-housing (domatia) in return for protection from herbivores. Our model system is the rattan ant-palm Korthalsia furtadoana, which grows swollen leaf sheaths as domatia and associates with two species of obligate host-ants, Camponotus sp90 and C. sp93, and with facultative Crematogaster and 'tramp' ant species. One ant-tree species is known to retaliate by tying the growth of domatia to the successful protection of new leaves, and non-protecting cheaters are rare. In contrast, K. furtadoana grows the domatium before the new leaf develops, suggesting that sanctioning may not be possible. We experimentally simulated herbivory by cutting leaves from shoots and found no difference in the mortality and growth of domatia on such 'cheated' shoots than on controls, confirming that K. furtadoana cannot sanction non-protectors. We then investigated the intensity of protection that Camponotus and Crematogaster ant-symbionts provide K. furtadoana. We demonstrate that C. sp90, which only inhabit half of colonised plants, vigorously protects leaves, that C. sp93 rarely protects, and that Crematogaster never protects. We then show that plants inhabited by C. sp90 have a higher growth rate than those inhabited by C. sp93. We conclude that C. sp90 is a protection mutualist, while C. sp93 and Crematogaster are parasites, the first such demonstrations for an ant-palm interaction. The presence of commonly occurring parasites, as well as rare tramp ants, provides the first clear correlative evidence that an inability to punish results in abundant cheating.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
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.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Tropical rain forests are well known as centres of insect diversity and much effort has focused on the role of larval host plant specificity in generating and maintaining this diversity, but fewer ...studies have examined the exploitation of different food resources by adults in this context. Tropical butterflies feed as adults on a wide range of resources and we examined the diversity and ecology of species feeding on rotting fruit and carrion in a tropical lowland rain forest in Sabah, Borneo. We found that species richness and diversity were significantly higher on carrion than on fruit, and that this pattern was repeated at genus and family level. There was little similarity in species assemblages on the two substrates and β-diversity between carrion and fruit comprised 33% of the total diversity of butterflies feeding on decaying matter. β-diversity between canopy gap and shade microhabitats comprised 21% of total species diversity on carrion but only 7% of the total on fruit, indicating greater functional diversity on carrion in terms of light preferences. Captures were strongly male-biased on carrion but not on fruit, and recapture rates were much lower on carrion than on fruit. Species from two subfamilies (Nymphalinae and Charaxinae) exploited both substrates and for Charaxinae, there was evidence from adult flight morphology that species on carrion were capable of faster more-powerful flight. These results support the notion of a distinctive carrion-feeding fauna comprising more mobile species, which may use carrion to meet additional nitrogen requirements resulting from greater musculature. However there was no relationship between flight morphology and substrate choice in the Nymphalinae, and carrion-feeding may not have a unitary explanation.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
We have successfully synthesized Fe-doped ZnO nanorods by a new and simple method in which the adopted approach is by using ammonia as a continuous source of O H - for hydrolysis instead of ...hexamethylenetetramine (HMT). The energy dispersive X-ray (EDX) spectra revealed that the Fe peaks were presented in the grown Fe-doped ZnO nanorods samples and the X-ray photoelectron spectroscopy (XPS) results suggested that Fe3+ is incorporated into the ZnO lattice. Structural characterization indicated that the Fe-doped ZnO nanorods grow along the c-axis with a hexagonal wurtzite structure and have single crystalline nature without any secondary phases or clusters of FeO or Fe3O4 observed in the samples. The Fe-doped ZnO nanorods showed room temperature (300 K) ferromagnetic magnetization versus field (M-H) hysteresis and the magnetization increases from 2.5 μemu to 9.1 μemu for Zn0.99Fe0.01O and Zn0.95Fe0.05O, respectively. Moreover, the fabricated Au/Fe-doped ZnO Schottky diode based UV photodetector achieved 2.33 A/W of responsivity and 5 s of time response. Compared to other Au/ZnO nanorods Schottky devices, the presented responsivity is an improvement by a factor of 3.9.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The diversity of beetle assemblages in different habitat types (primary forest, logged forest, acacia plantation and oil palm plantation) in Sabah, Malaysia was investigated using three different ...methods based on habitat levels (Winkler sampling, flight-interception-trapping and mist-blowing). The overall diversity was extremely high, with 1711 species recorded from only 8028 individuals and 81 families (115 family and subfamily groups). Different degrees of environmental changes had varying effects on the beetle species richness and abundance, with oil palm plantation assemblage being most severely affected, followed by acacia plantation and then logged forest. A few species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from the rest. The effects of environmental variables (number of plant species, sapling and tree densities, amount of leaf litter, ground cover, canopy cover, soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities correlated with species richness, abundance and composition of understorey beetles while ground cover correlated only with the species richness and abundance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species and individuals. Environmental changes affected the trophic structure with proportionally more herbivores (abundance) but fewer predators (species richness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this study.
Testicular germ cell tumors (TGCT), histologically classified as seminomas and nonseminomas, are believed to arise from primordial gonocytes, with the maturation process blocked when they are ...subjected to DNA methylation reprogramming. SNPs in DNA methylation machinery and folate-dependent one-carbon metabolism genes have been postulated to influence the proper establishment of DNA methylation.
In this pathway-focused investigation, we evaluated the association between 273 selected tag SNPs from 28 DNA methylation-related genes and TGCT risk. We carried out association analysis at individual SNP and gene-based level using summary statistics from the Genome Wide Association Study meta-analysis recently conducted by the international Testicular Cancer Consortium on 10,156 TGCT cases and 179,683 controls.
In individual SNP analyses, seven SNPs, four mapping within MTHFR, were associated with TGCT risk after correction for multiple testing (q ≤ 0.05). Queries of public databases showed that three of these SNPs were associated with MTHFR changes in enzymatic activity (rs1801133) or expression level in testis tissue (rs12121543, rs1476413). Gene-based analyses revealed MTHFR (q = 8.4 × 10-4), methyl-CpG-binding protein 2 (MECP2; q = 2 × 10-3), and ZBTB4 (q = 0.03) as the top TGCT-associated genes. Stratifying by tumor histology, four MTHFR SNPs were associated with seminoma. In gene-based analysis MTHFR was associated with risk of seminoma (q = 2.8 × 10-4), but not with nonseminomatous tumors (q = 0.22).
Genetic variants within MTHFR, potentially having an impact on the DNA methylation pattern, are associated with TGCT risk.
This finding suggests that TGCT pathogenesis could be associated with the folate cycle status, and this relation could be partly due to hereditary factors.
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