TY - JOUR T1 - Co-declines in large mammals and dung beetles: an impending ecological cascade JF - Oikos Y1 - 2009 A1 - Nichols, E. A1 - Gardner, T. A. A1 - Peres, C. A. A1 - Spector, S. SP - 481 EP - 487 KW - co-decline KW - conservation KW - decline KW - extinction KW - mammal KW - resource AB - Biodiversity loss can precipitate extinction cascades and impair ecological processes. These ‘downstream’ effects will be exacerbated if functionally important taxa are tightly linked with species threatened by extinction or population decline. We review the current evidence that such a scenario is currently playing out in the linked declines of persistently hunted
mammal populations and the dung beetles communities (Coleoptera: Scarabaeidae: Scarabaeinae) that depend on them for adult and larval food resources. Through a close evolutionary association, mammal assemblages have played a fundamental role in structuring extant dung beetle communities. Today many game mammal species’ populations are severely depleted by subsistence or commercial hunting, especially in tropical forest systems. Multiple lines of evidence from temperate and tropical systems indicate that the regional-scale decline or extirpation of medium and large bodied mammal faunas can severely disrupt the diversity and abundance of dung beetle communities through alterations in the composition and availability of dung resources. These observed community disassemblies have significant short- and long-term implications for the maintenance of key ecosystem processes including nutrient recycling and secondary seed dispersal. Identifying the species- and community-level traits that buffer or exacerbate these species and functional responses is essential if we are to develop a better understanding of the cascading ecological consequences of hunting in tropical forests. VL - 118 IS - 4 N1 - [gmap markers=blank::40.782003745886755,-73.97163391113281 |zoom=15 |center=40.78531820515752,-73.9749813079834 |width=100% |height=400px |control=Small |type=Satellite] ER - TY - JOUR T1 - Quantifying the biodiversity value of tropical primary, secondary, and plantation forests JF - Proceedings of the National Academy of Sciences Y1 - 2007 A1 - Barlow, J. A1 - Gardner, T. A. A1 - Araujo, I. S. A1 - Avila-Pires, T. C. A1 - Bonaldo, A. B. A1 - Costa, J. E. A1 - Esposito, M. C. A1 - Ferreira, L. V. A1 - Hawes, J. A1 - Hernandez, M. I. M. A1 - Hoogmoed, M. S. A1 - Leite, R. N. A1 - Lo-Man-Hung, N. F. A1 - Malcolm, J. R. A1 - Martins, M. B. A1 - Mestre, L. A. SP - 18555 EP - 18560 KW - Amazon KW - biodiversity indicators KW - congruence KW - conservation KW - Tropical forests VL - 104 ER - TY - JOUR T1 - The cost-effectiveness of biodiversity surveys in tropical forests JF - Ecology Letters Y1 - 2008 A1 - Gardner, T. A. A1 - Barlow, J. A1 - Araujo, I. S. A1 - Avila-Pires, T. C. A1 - Bonaldo, A. B. A1 - Costa, J. E. A1 - Esposito, M. C. A1 - Ferreira, L. V. A1 - Hawes, J. A1 - Hernandez, M. I. M. A1 - Hoogmoed, M. S. A1 - Leite, R. N. A1 - Lo-Man-Hung, N. F. A1 - Malcolm, J. R. A1 - Martins, M. B. A1 - Mestre, L. A. SP - 139 EP - 150 KW - biodiversity KW - cost-effectiveness KW - indicator species KW - sampling efficiency KW - Tropical forests AB - The identification of high-performance indicator taxa that combine practical feasibility and ecological value requires an understanding of the costs and benefits of surveying different taxa. We present a generic and novel framework for identifying such taxa, and illustrate our approach using a large-scale assessment of 14 different higher taxa across three forest types in the Brazilian Amazon, estimating both the standardized survey cost and the ecological and biodiversity indicator value for each taxon. Survey costs varied by three orders of magnitude, and dung beetles and birds were identified as especially suitable for evaluating and monitoring the ecological consequences of habitat change in our study region. However, an exclusive focus on such taxa occurs at the expense of understanding patterns of diversity in other groups. To improve the cost-effectiveness of biodiversity research we encourage a combination of clearer research goals and the use of an objective evidence-based approach to selecting study taxa. VL - 11 ER - TY - JOUR T1 - Understanding the biodiversity consequences of habitat change: the value of secondary and plantation forests for neotropical dung beetles JF - Journal of Applied Ecology Y1 - 2008 A1 - Gardner, T. A. A1 - Hernandez, M. I. M. A1 - Barlow, J. A1 - Peres, C. A. SP - 883 EP - 893 KW - biomass KW - brazil KW - deforestation KW - habitat change KW - habitat value KW - sampling bias KW - Scarabaeinae KW - Tropical forests AB - 1. Secondary and plantation forests are becoming increasingly widespread in the tropics. A recent meta-analysis on the impacts of land-use change on tropical forest dung beetles concluded that regenerating forests can be effective in helping to offset species loss following deforestation. How- ever, our understanding of the extent to which these results can be generalized to new locations remains very poor. 2. We attempted to overcome many of the design limitations that characterize previous studies by collecting spatially independent dung beetle samples from primary, secondary and Eucalyptus plantation forests in north-east Brazilian Amazonia across a large quasi-experimental landscape that minimized confounding edge and fragmentation effects. 3. We recorded 9203 dung beetles, comprising 85 species. Species richness was significantly higher in primary forest and the majority of species were more abundant there than elsewhere, whereas secondary and plantation sites harboured an impoverished subset of primary forest species. 4. Our data illustrate the low value of tropical secondary and plantation forests for dung beetles in our study area, and our conclusions are more pessimistic than those of earlier studies. 5. Because of differences in the order of species rank-abundance and rank-biomass patterns, re-coding community data from abundance to biomass significantly altered the analytical weight of individual species in determining community patterns. Larger bodied beetles were more prone to local extinctions and abundance declines and this effect was consistent both within and between genera. 6. Synthesis and applications . Our study demonstrates that secondary and plantation forests in a large neotropical landscape host exceptionally impoverished dung beetle communities. Furthermore, the depletion of beetle abundance combined with a reduction in average body mass in converted forests is likely to have detrimental consequences for the maintenance of dung beetle-mediated ecosystem services in these habitats. Differences in biogeographical and landscape context, and the influence of common limitations in sampling design, may explain why many other studies have painted a more optimistic picture of the conservation value of anthropogenic habitats. In the absence of further evidence we caution strongly against the claim that forest regeneration schemes on degraded land can effectively offset the loss of species following deforestation, and urge that conservation strategies prioritize the protection of remaining areas of primary forest. VL - 45 ER -