Plant functional types and traits as biodiversity indicators for tropical forests: two biogeographically separated case studies including birds, mammals and termites (original) (raw)
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BIODIVERSITY INDICATOR GROUPS OF TROPICAL LAND-USE SYSTEMS: COMPARING PLANTS, BIRDS, AND INSECTS
Ecological Applications, 2004
Tropical landscapes are dominated by land-use systems, but their contribution to the conservation of biodiversity is largely unknown. Since changes in biodiversity in response to human impact are known to differ widely among taxonomic groups and guilds, there is a need for multidisciplinary collaboration of plant, vertebrate, and invertebrate experts. We used inventories of trees, understory plants, birds (subdivided into endemics, insectivores, frugivores/nectar feeders), butterflies (endemics, fruit feeders), and dung beetles in Sulawesi (Indonesia) to characterize a gradient from near-primary to secondary forests, agroforestry systems, and annual crops. As expected, overall species richness tended to decrease within this gradient of increasing habitat modification, but, in contrast to previous studies, we found the species richness between most taxonomic groups to be significantly correlated (36 out of 38 pairwise comparisons). However, on average only 48% of the variance could be explained (within the five main groups), and only a few taxonomic groups/guilds turned out to be good predictors for others: for example, trees for fruit-and nectar-feeding birds (88% explanation) and fruit-feeding butterflies (83%), endemic birds for endemic butterflies (72%), and frugivorous/nectar-feeding birds for fruit-feeding butterflies (67%). Although biodiversity of land-use systems showed taxonomic group-and guild-specific differences, most groups were affected in a similar way by habitat modification. Near-primary forest sites proved to be of principal importance for conservation; however, land-use systems such as secondary forests (for understory plants, birds, and butterflies) and agroforestry systems (for butterflies) supported relatively high numbers of species and might play a significant role for biodiversity conservation in tropical landscapes.
Quantifying the biodiversity value of tropical primary, secondary, and plantation forests
Proceedings of the …, 2007
Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests. biodiversity indicators ͉ congruence ͉ conservation ͉ tropical forests ͉ Amazon
Organisms Diversity & Evolution, 2003
Macroinvertebrates have an important role in the maintenance of soil structural stability and fertility in many natural and man-modified habitats. Efficient cataloguing of these animals, as a part of rapid biodiversity assessments, is hampered by high species richness, inherent inaccessibility and a strong tendency towards aggregated distribution. Current debate concerning the relative merits of transects (rapid, but at best semi-quantitative) and alternative sampling approaches such as grid-based or randomised placements of monoliths or cores (labour intensive, but statistically preferable) has initiated a search for satisfactory indicator groups or surrogates of belowground faunal diversity. Here, we use well-characterised, forest-derived plant and termite assemblages to show there can be a key role for plant indicators. We catalogued all vascular plant species, plant functional attributes (PFAs), plant functional types (PFTs), and vegetational structure in seven IBOY-designated sites along a gradient of disturbance and land-use intensification in lowland Sumatra, using a rapid survey protocol. We simultaneously sampled the termite assemblage in the same sites by a more exhaustive process involving microhabitat exploration. There were highly significant, positive correlations between species richness of all termites (and of soil-feeders, the most important termite functional group) and, respectively, mean canopy height (r > 0.96), woody plant basal area (r > 0.95), the ratio of plant species richness to richness of PFTs (r > 0.97), and plant species richness (r > 0.85). There was no significant correlation between any individual plant and termite species. There were significant correlations between 18 individual PFAs and 24 of the 54 termite species, and between 12 PFTs and 38 termite species. In addition, 6 PFTs and 10 PFAs were highly correlated with termite species richness and relative abundance. Causal linkages between termites and their plant predictors are briefly discussed. Plant-based heterogeneity and aboveground habitat structure may therefore predict termite diversity response to disturbance. We conclude that for rapid, multi-taxon surveys including belowground macroinvertebrates, logistic efficiency may be achieved by the use of specific, readily observable plant indicators.
Ecological Indicators, 2021
Despite the importance of non-timber forest products (NTFPs) for local livelihoods in tropical countries and the increasing attention for biodiversity-ecosystem services relationships, it remained unclear how the ecosystem service of NTFP provisioning is related to plant diversity. Although it is generally assumed that plant diversity is positively related to ecosystem services, this had not been assessed for NTFP provisioning. We applied bivariate and multiple regression models to explore the relationships between the abundance of 58 commercially relevant NTFP species and woody plant diversity across 287 plots of tropical forests in Northern Suriname. We found that NTFP abundance showed both positive and negative relationships to plant diversity indicators. In contrast to expectations, NTFP abundance was negatively related to woody species richness. In addition, across the plots disproportionately few (2-6) NTFP species determined >50% of NTFP abundance. The occurrence and the identity of these 'NTFP oligarchs' was associated to specific floristic compositions. Overall, more than half, i.e. 55.9%, of the observed variation in NTFP abundance could be explained by a combination of taxonomic and structural plant diversity indicators. Our case study findings are relevant for conservation policies in general. In most countries NTFPs are not on the agenda of governments and current tropical conservation policies often focus on forests with high species richness and/or carbon stocks. Our findings indicate that current policies may not cover valuable forests in terms of high NTFP abundance. To support sustainable NTFP provisioning, additional conservation efforts would need to include those vegetation types with high NTFP abundance.
Journal for Nature Conservation, 2015
Rapid ecological assessment methods, such as Rapid Ecological Assessments (REA) and Indexes of Biotic Integrity (IBI) are useful tools for the selection of priority areas for biodiversity conservation. However, the majority of rapid assessment methods are based on data from a single taxonomic group; a multi-taxa index should provide a more integrated evaluation of the response of a disturbed system. In this study, we propose a new, easy-to-follow, integrated Index of Biotic Integrity (IBIint) which combines plants and birds to assess ecological integrity of tropical forest fragments. This integrated index combines the information of two previously developed rapid assessment methods: REA for plants and IBI for birds. These two indexes were built based on key vegetation features and on levels of sensitivity to forest fragmentation of bird species. We applied IBI, REA and the new IBIint indexes on the characterization of 10 forest fragments and in a large continuous forest block (reference area). We also tested the correlation of the proposed index (IBIint), REA and IBI with patch size, forest amount and connectivity at four spatial scales (250, 500, 1000, 1500 m). Our hypothesis was that IBIint would be more correlated with landscape metrics than the REA and IBI. As expected, IBIint was the more accurate index once it was explained by all landscape variables: area of forest fragments; forest connectivity; and, percentage of forest cover at four spatial scales. REA and IBI were explained only by one of those parameters. We conclude that IBIint can be an excellent tool to aid conservationists and managers for defining conservation strategies in scenarios with fast habitat loss.
Patterns of taxonomic and functional diversity of termites along a tropical elevational gradient
Biotropica, 2016
The Brazilian Cerrado harbors great floristic and structural diversity composed of a mosaic of natural vegetation types and anthropogenic environments such as introduced pastures. Here, our goal was to evaluate the patterns of taxonomic and functional diversity of dung beetles in a human-modified landscape in Brazilian Cerrado. For this, we evaluated the species richness, species composition and abundance (non-weighted by abundance) and species diversity (Shannon index-weighted by abundance) and three functional indexes (functional richness, functional evenness and functional dispersion). We collected the insects in fragments of Cerrado (Cerrado stricto sensu), riparian forests under pressure of timber removal and livestock and exotic pastures (Urochloa spp.) in Anastácio and Aquidauana, Mato Grosso do Sul, Brazil. We used pitfall traps baited with human feces and fresh capybara dung, a large native rodent, as a representative of the mammal regional fauna. Dung beetle richness was higher in Cerrado fragments, while the abundance was higher in exotic pastures and riparian forests. Species composition differed among vegetation types. Finally, the species diversity and functional diversity did not differ among vegetation types. Thus, we demonstrated the information generated by conceptually similar indexes (e.g. functional richness, species richness and species diversity) may not provide similar information on dung beetles responses to disturbance due to differences in the weighting on species abundance. Finally, the use of taxonomic and functional metrics generate complementary information that can helps us to reach more efficient conclusions in terms of biodiversity conservation and ecosystem functionality in human-modified variegated landscape.
Ecosystem Services, 2020
This paper sheds light on the state of our knowledge of relationships between plant diversity and tropical forests ecosystem services. We systematically reviewed the empirical evidence of relationships between three ecosystem services: carbon stock and sequestration, timber provisioning and non-timber forest product (NTFP) provisioning, and three dimensions of plant diversity: taxonomic, functional and structural. We carried out metaanalyses to assess their validity across spatial scales and plot sizes. We found that indicators of all three dimensions of plant diversity have reported relationships with at least two of the studied ecosystem services, but there has been limited and inconsistent use of plant diversity indicators and little attention for relationships with timber and NTFP services. Nevertheless, we found that tree species richness showed robust significant positive correlations with carbon stock across the tropics, and that the geographical extent of the study area had a significant negative effect on the strength of this relationship, where the strength of the relationship decreased with increasing geographical extent. This paper reveals a knowledge gap for services other than carbon stock and shows that at local to regional spatial scales, synergies can be achieved between policies focused on biodiversity conservation and maintenance of carbon stocks.
Biodiversity of Tropical Forests
2016
The quantification of tropical tree biodiversity worldwide remains an open and challenging problem. In fact, more than two-fifths of the global tree population can be found either in tropical or sub-tropical forests1, but species identities are known only for ≈ 0.000067% of the individuals in all tropical forests2. For practical reasons, biodiversity is typically measured or monitored at fine spatial scales. However, important drivers of ecological change tend to act at large scales. Conservation issues, for example, apply to diversity at global, national or regional scales. Extrapolating species richness from the local to the global scale is not straightforward. Indeed, a vast number of different biodiversity estimators have been developed under different statistical sampling frameworks3–7, but most of them have been designed for local/regional-scale extrapolations, and they tend to be sensitive to the spatial distribution of trees8, sample coverage and sampling methods9. Here, we ...
Tropical forests are one of the most diverse (1 ha may contain more than 1000 plant species) and highly productive ecosystems on the earth. They cover 15.0% of the earth's surface and harbored 80% terrestrial biodiversity. Tropical forests are home to thousands of endemic, rare, endangered, and threatened wildlife species, which play a significant role in ecosystem functions, such as pest control, pollinators, and seed dispersal. Wildlife species are bioindicators of the tropical forest ecosystems, that is, their presence or absence may provide the information about the habitat dynamics, such as vegetation structure, food resources, productivity, and anthropogenic disturbances. Despite being rich in wildlife resources, tropical forests have been extensively lost and degraded by human intervention , and their destruction is still continuous in a variety of ways. The current information on the tropical forests as an ideal habitat for a wide array of wildlife species is inadequate. It is highly essential to examine with solid grasp the suitability of the tropical forest as attractive habitat for diversity of wildlife species to understand their functional role fragile forest ecosystem and to formulate the better conservation and management strategies in future.