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Map of PNG showing PSP locations across the country. Empty circles represent 122 logged-over PSPs, while 13 unlogged PSPs are represented by black circles. Province boundaries as well as province names are shown.
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Unsustainable exploitation of tropical forest resources is raising worldwide concern. In Papua New Guinea (PNG) timber harvesting has been identified as a major contributor to deforestation and forest degradation but its impact on biodiversity is still poorly understood. In this study we investigated the effect of selective logging on tree taxonomi...
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Over the last decades there have been a considerable number of deforestation studies in Latin America reporting lower rates compared with other regions; although these studies are either regional or local and do not allow the comparison of the intraregional variability present among countries or forest types. Here, we present the results obtained f...
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... Several studies have been conducted to assess the impact of logging on the biomass stock [11], basal area [12], and carbon stock and sequestration [13,14]. However, the impact of logging on tree richness, diversity, and composition is still poorly understood [15]. To fill the gap, this study investigates the impact of logging activities on the richness, diversity, and species composition of lowland and montane forests using data from the National Forest Inventory (NFI) [16]. ...
... Unlogged forests have a notably higher cover with larger and taller trees. However, no statistically significant differences were found in terms of diversity, confirming the results of Testolin et al [15]. Structural differences are expected to reduce in time [12], while differences in species composition are more persistent due to the establishment of light-demanding pioneer species, which will only very slowly be replaced by old-growth tree species [25]. ...
The forests of Papua New Guinea (PNG) play a fundamental role in sustaining the livelihood of local communities and provide significant income to the country derived from the export of timber. After land conversion for agriculture, logging has been identified as the second most common disturbance factor. Conservation activities must be based on a better understanding of the impact of logging. This study analyzes the differences in terms of structure, diversity, and tree species composition between forest types and disturbance regimes in PNG forests. Data were collected from 117 circular plots surveyed according to the protocol of the National Forest Inventory. Sites were situated in unlogged and logged lowland (99 plots) and montane forests (18 plots). The survey recorded 4,558 tree specimens belonging to 258 families, 323 genera, and 789 species. Although data showed the need for a further sampling effort, some general patterns emerged. Montane forest is clearly distinct in terms of structure, diversity, and species composition. Unlogged and logged lowland forests differed only in terms of structure and species composition, but not according to diversity indexes. Thus, logging activities are having an impact mainly on lowland and most accessible areas. Our study established a baseline related to the tree species component of PNG forests. Together with other taxonomic groups, it will be used to monitor the implementation of initiatives aimed at promoting the reduction of emissions from deforestation and forest degradation (REDD+), which can offer significant economic, environmental, and social benefits.
... The majority of the analysed studies highlighted no difference or just a slight decrease in vascular plant richness and evenness between forest stands harvested via selective logging and control areas with unharvested stands [51][52][53][54]. Furthermore, several studies highlighted the influence of selective logging on tree biodiversity and the magnitude of the intervention, with limited biomass removal (removal of approximately 3 trees per hectare equal to a harvest volume of approximately 20 m 3 per hectare) generally leading to a lower impact on biodiversity indices [55][56][57]. ...
Purpose of Review Biodiversity is one of the most important features of forest ecosystems. One of the goals of Sustainable
Forest Management is to reduce biodiversity disturbance, which can occur as a consequence of timber harvesting. The aim
of this review was to define which silvicultural systems and forest operations can have an influence on forest tree biodiversity
by summarising the findings of nearly 60 papers published in the last ten years (2013–2022).
Recent Findings In natural forest ecosystems characterised by a high level of structural complexity, such as uneven-aged
tropical forests, selective logging and retention forestry are, in general, suitable forms of intervention that have a limited
impact on tree biodiversity. Forest operations, in particular, should be of low intensity and try to simulate as much as possible
small-scale natural disturbances. Thinning has proved to be a valid treatment for managing tree biodiversity. However,
it is important to shape the magnitude of thinnings according to the management aims. Limited removal is recommended
in interventions for maintaining the current structure, and more extensive removal is appropriate in cases when a change in
species composition is expected, e.g. in the conversion of planted coniferous stands to uneven-aged mixed or broadleaved
stands. In addition, coppicing is suitable for maintaining tree biodiversity due to its effectiveness in fostering the presence
of light-demanding tree species. Findings show that it is important to establish the right rotation age, considering that an
excessively short period between coppicing interventions can be detrimental to functional biodiversity.
Skid trails and landing sites represent suitable areas for the initial establishment of natural regeneration. However, generally,
the level of biodiversity on these sites declines with time as a consequence of soil compaction, thus highlighting the
importance of the forest infrastructure network planning.
Summary In uneven-aged tropical forests, selective logging and retention forestry are the most suitable options for maintaining
tree biodiversity. Thinning and coppicing help to manage biodiversity, whilst intensive thinning helps to change species
composition. Skid trails and landing sites can support natural regeneration. Recommendations and management options were
developed, as well as possible future research directions. The authors recommend that future studies should investigate how
much tree biodiversity depends on different levels of harvesting technology applied within the same silvicultural treatment.
... As in other parts of Southeast Asia, tropical forest resources have recently been exploited at a high rate [27]. In this situation, studies with conservation aims have focused on tree diversity and forest structure, whereas herbaceous, liana, palms, and shrubs species have often been neglected [28]. ...
... The taxonomic species difference among the forest types (lowland primary, lowland logged, and lower montane forest) was tested with a pairwise PERMA-NOVA (999 permutations) using the pairwise.adonis function in R package vegan [28]. Significant differences among forest types were tested using a customized pairwise adonis function with Jaccard dissimilarities and Bonferroni correction for the p values. ...
... In this project, we recorded 463 nonwoody species accounting for 50% of the total plant diversity. In a larger study, from the same NFI, employing 117 plots of the same size reported a total of 789 tree species [28]. These two studies were conducted in the same study areas (NFI); beside the different numbers of plots, they suggest the critical importance of herbs, shrubs, palms, and lianas as taxonomic groups in PNG forests and tropical ecosystems. ...
This study appraises the richness of nonwoody species (ferns, herbs, lianas, palms, and shrubs) in 31 sites across undisturbed and disturbed forests in the lowland of Papua New Guinea (PNG) and at montane forest sites at 2,700 m a.s.l. The assessment was conducted following the PNG National Forest Inventory protocol. The results indicate that with 463 nonwoody species, the tropical forest of PNG has remarkable species richness. No significant difference was observed in richness among lowland, logged and pristine, and montane forests. The study shows that the richness of nonwoody species increases with elevation, but this trend is different when considering the taxonomic group separately. Palms and lianas decrease along the elevation, whereas ferns, herbs, and shrubs are positively correlated with elevation. The species composition between lowland forest and mountain sites is different, with a tree fern and an Araliaceae as an indicator of the mountain forest. The findings demonstrate a high taxonomic richness of nonwoody species in PNG, supporting previous research but highlighting the significant contribution of nonwoody species to the overall plant richness in a tropical habitat.
... In PNG, the tropical forest is of considerable extent, particularly in respect of mountain and upper mountain areas [12]. The lowland component has been largely converted into agricultural uses and is characterized by increasing fragmentation and degradation [13,14]. Species richness trends in the human-modified tropical forest are determined by the decrease and homogenization of flora in fragments disturbed over a long period [15]. ...
This study aims to analyze the occurrence and composition of ferns along an elevational gradient and among different forest types and disturbance regimes in Papua New Guinea (PNG). The assessment was conducted using the monitoring protocol of the National Forest Inventory. The investigation revealed a high richness of ferns, with 122 species or morphospecies from 51 genera and 21 families. Among them, 81 species were terrestrial and 16 were epiphytes. The project also highlighted increasing richness with elevation, both for terrestrial and epiphytic ferns. Reflecting other environmental variables, elevation was a significant proxy factor in determining the taxonomic composition. Lowland forest was clearly differentiated from the montane one, which was characterized by epiphytic species from the Drynaria and Ctenopteris genera. Lowland disturbed and primary forests were slightly differentiated in terms of fern composition, the latter characterized by sciophilous species belonging to the Polypodium, Microlepia, and Pronephrium genera and the former mainly by species of the Gleichenia genus adapted to forest margins and gaps. The research points to the richness of ferns in PNG and their effectiveness as a potential indicator to characterize and monitor forest types and their conservation status with respect to a disturbance regime. In the future, studies should aim to increase species sampling in abundance and seek precision in understanding species response variables in diverse forest regimes.
... However, limited information is available on the impacts of logging on herbaceous plant species richness, diversity, and composition. Studies were mainly focused on tree species due to their economic and ecological importance [6][7][8][9][10][11][12]. Herbaceous communities in the tropical rainforest are less investigated [13][14][15][16], and there is still a significant knowledge gap about the impact of logging activities on them, despite they provide important nontimber products and play significant ecological functions. ...
The impact of logging activities on species richness, diversity, and composition of the ground herbaceous layer of the lowland forest of Papua New Guinea was analyzed. Data from the first multipurpose National Forest Inventory were collected in 52 plots from logged and unlogged low altitude forest on plains and fans (P) and forest on uplands (H) in Madang, West New Britain and Central Provinces. The abundance of 10,609 ground herbaceous plants classified in 174 species from 103 genera and 35 families. Based on importance values, Arecaceae was the dominating family in both logged and unlogged P forest type, while Urticaceae and Arecaceae were dominating respectively in logged and unlogged H forest type. At species level, Donax canniformis and Elatostema beccarii are dominating the P type, and Elatostema novoguineensis and Selaginella durvillei the H type. Analysis of species richness, diversity, and composition showed significant differences between the two types with the H type being richer and more diverse than P type. No differences emerged between logged and unlogged of both types, indicating that the current intensity of disturbance does not seem to have a significant impact on the ground herbaceous layer. Since herbaceous species are an important component of the tropical forest diversity, further inventories must be conducted along a wider elevation gradient to make these results more robust and better observe species turn over patterns and beta diversity.
... In the context of human disturbance, this implicates the management of logging practices. Although selective logging seems not to affect plant species richness, diversity and evenness (Testolin et al., 2016), it can significantly reduce species abundance (Meijaard and Sheil, 2008) and affect plant community and structure (Potts, 2011;Testolin et al., 2016), resulting in a significant dissimilarity in species composition between logged and unlogged forests (Testolin et al., 2016). These affected plant species may comprise those preferred by great apes: for example, in Kanyawara logging led to a change in the basal area of 18 fruit species consumed by chimpanzees, and many additional species of chimpanzee diet were directly extracted for commercial purposes (Potts, 2011). ...
... In the context of human disturbance, this implicates the management of logging practices. Although selective logging seems not to affect plant species richness, diversity and evenness (Testolin et al., 2016), it can significantly reduce species abundance (Meijaard and Sheil, 2008) and affect plant community and structure (Potts, 2011;Testolin et al., 2016), resulting in a significant dissimilarity in species composition between logged and unlogged forests (Testolin et al., 2016). These affected plant species may comprise those preferred by great apes: for example, in Kanyawara logging led to a change in the basal area of 18 fruit species consumed by chimpanzees, and many additional species of chimpanzee diet were directly extracted for commercial purposes (Potts, 2011). ...
... In the context of human disturbance, this implicates the management of logging practices. Although selective logging seems not to affect plant species richness, diversity and evenness (Testolin et al., 2016), it can significantly reduce species abundance (Meijaard and Sheil, 2008) and affect plant community and structure (Potts, 2011;Testolin et al., 2016), resulting in a significant dissimilarity in species composition between logged and unlogged forests (Testolin et al., 2016). These affected plant species may comprise those preferred by great apes: for example, in Kanyawara logging led to a change in the basal area of 18 fruit species consumed by chimpanzees, and many additional species of chimpanzee diet were directly extracted for commercial purposes (Potts, 2011). ...
The ongoing global decline in mammal populations has led researchers and conservationists to question which factors drive their abundance and distribution. Specifically, there is an urgent need to understand how the ranging behaviour of mammals determines their response to human-induced environmental changes. Threats such as hunting and habitat fragmentation and degradation through agricultural expansion and logging have received considerable attention. However, a potential threat resulting from the non-consumptive use of natural systems by humans has often been overlooked. The ecological and anthropogenic factors influencing the abundance and distribution of mammal populations in tropical forests were evaluated using great apes (Gorilla gorilla gorilla and Pan troglodytes troglodytes) as focal species in order to improve understanding of the drivers of local extinction of species. To achieve this goal, data on diet, fruit phenology, botany, and nest abundance and distribution were collected in a design involving a sampling grid and line transects. Data were analysed using modelling techniques in R and ArcGIS. The preferred fruiting plants for both gorillas and chimpanzees were more abundant in chimpanzee-preferred nesting habitats, while their fallback fruits were more abundant in gorilla-preferred nesting habitats. The patterns of habitat use by both gorillas and chimpanzees varied seasonally. In the absence of human disturbance, the distribution of gorilla nests was predicted by the availability of their preferred nesting habitats, while the distribution of chimpanzee nests was predicted by elevation and their preferred nesting habitats. However, when considering the research camp and human settlements, the distribution of gorilla nests was predicted first by the distribution of human settlements and then by their preferred nesting habitats, while chimpanzee nests remained predicted by elevation and their preferred nesting habitats. The long-term monitoring of great ape nests in the research site revealed a decline in both gorilla and chimpanzee populations resulting from an increase in hunting activities in the site. Results suggest that in the absence of human disturbance, ecological factors (habitat preference, seasonal patterns of fruit availability, fruit preference, and spatial distribution of habitat types) may be responsible for seasonal changes in mammal population abundance and distribution. Animal species traits (body size, terrestrial/arboreal, level of specialization/generalization, and competitive inferiority/superiority) have a profound influence on the response of mammals to human activities. Due to their spatial flexibility and their reliance on more available fallback food sources when preferred fruits are scarce, gorillas may vacate areas disturbed by hunting and non-hunting human activities and related noise. Chimpanzees, on the other hand, persist in their preferred nesting habitats despite human disturbance due to their high level of specialisation in fruit consumption. Additionally, the competitive dominance of chimpanzees over gorillas facilitated by their grouping patterns may allow them to cope with human disturbance better than gorillas. Human impacts other than direct killing of animals may influence the abundance and distribution of great ape populations and may account for the long-term decrease in population size. As habitat and resource heterogeneity facilitate the local coexistence of gorillas and chimpanzees, preserving both preferred and fallback fruiting plant species is crucial. Patterns observed in great apes may be an indication that human disturbance is also negatively influencing other mammals. However, species may respond differently to human disturbance, depending on their interaction with other sympatric mammals, their level of dietary specialisation, and their interaction with their physical environment. Further research is required to assess how these biological traits affect mammal response to anthropogenic disturbance. Furthermore, future studies should investigate the threshold beyond which the non-consumptive use of natural systems by humans becomes detrimental to species and their habitats.
... In the context of human disturbance, this implicates the management of logging practices. Although selective logging may not affect plant species richness, diversity and evenness (Testolin et al. 2016), it can significantly reduce species abundances (Meijaard and Sheil 2008) and affect plant community and structure (Potts 2011;Testolin et al. 2016), resulting in a significant dissimilarity in plant species composition between logged and unlogged forests (Testolin et al. 2016). These affected plant species may include those preferred by great apes: for example, in Kanyawara, logging led to a change in the basal area of 18 fruit species consumed by chimpanzees, and many additional species of the chimpanzee diet were directly extracted for commercial purposes (Potts 2011). ...
... In the context of human disturbance, this implicates the management of logging practices. Although selective logging may not affect plant species richness, diversity and evenness (Testolin et al. 2016), it can significantly reduce species abundances (Meijaard and Sheil 2008) and affect plant community and structure (Potts 2011;Testolin et al. 2016), resulting in a significant dissimilarity in plant species composition between logged and unlogged forests (Testolin et al. 2016). These affected plant species may include those preferred by great apes: for example, in Kanyawara, logging led to a change in the basal area of 18 fruit species consumed by chimpanzees, and many additional species of the chimpanzee diet were directly extracted for commercial purposes (Potts 2011). ...
... In the context of human disturbance, this implicates the management of logging practices. Although selective logging may not affect plant species richness, diversity and evenness (Testolin et al. 2016), it can significantly reduce species abundances (Meijaard and Sheil 2008) and affect plant community and structure (Potts 2011;Testolin et al. 2016), resulting in a significant dissimilarity in plant species composition between logged and unlogged forests (Testolin et al. 2016). These affected plant species may include those preferred by great apes: for example, in Kanyawara, logging led to a change in the basal area of 18 fruit species consumed by chimpanzees, and many additional species of the chimpanzee diet were directly extracted for commercial purposes (Potts 2011). ...
The present study used abundance and habitat variables to design High Conservation Value Forests for wildlife protection. We considered great apes (Gorilla gorilla gorilla and Pan troglodytes troglodytes) as model species, and we used nest surveys, dietary analysis and botanical inventories to evaluate whether the traditional methods that use abundance data alone were consistent with the survival of the species. We assumed that setting a local priority area for animal conservation can be made possible if at least one variable (abundance or habitat variables) is spatially clustered and that the final decision for a species may depend on the pattern of spatial association between abundance, nesting habitat and feeding habitat. We used Kernel Density Estimation to evaluate the spatial pattern of each biological variable. The results indicate that all three variables were spatially clustered for both gorillas and chimpanzees. The abundance variables of both animal species were spatially correlated to their preferred nesting habitat variables. But while the chimpanzee feeding habitat variable was spatially correlated to the abundance and nesting habitat variables, the same pattern was not observed for gorillas. We then proposed different methods to be considered to design local priority areas for the conservation of each great ape species. Alone, the abundance variable does not successfully represent the spatial distribution of major biological requirements for the survival of wildlife species; we, therefore, recommend the integration of the spatial distribution of their food resources to overcome the mismatch caused by the existence of a biological interaction between congeneric species.
