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Alta Floresta, Brazil

Pitman N.C.A.,Amazon | Pitman N.C.A.,Duke University | Norris D.,Fundacao Ecologica Cristalino | Gonzalez J.M.,Amazon | And 8 more authors.
Biodiversity and Conservation

Long-term monitoring of tropical forest animals lags far behind long-term monitoring of tropical forest plants, compromising ecologists' ability to identify parallel trends. On 257 occasions over 4 years, park guards in a newly protected lowland Amazonian forest in southeastern Peru tallied individuals of 31 reptile, bird, and mammal species sighted along a 47-km stretch of river. Each survey entailed ~3 h of observation from a motorized boat; total survey effort was 892 h and ~12,048 km. Our primary goals were descriptive: to establish baseline sighting rates for these species and to document trends over time and the influence of environmental and sampling factors on sightings. Our secondary goals were to identify the advantages and disadvantages of river-based monitoring and to assess how useful these data are for ecologists and protected areas managers. Over the 4 years of monitoring we observed 1.8 animals/km. More than 90% of recorded individuals belonged to seven common taxa: two reptiles, four birds, and one mammal. Season was the most frequent correlate of sighting frequency; sightings increased in dry season. For the majority of taxa common enough to analyze, sightings increased over the 4 years of monitoring; this is possibly a result of reduced hunting since the establishment of the protected area. Compared to forest-based surveys, river-based surveys were inefficient at recording most mammals. Results to date suggest that river-based surveys can be a valuable, inexpensive tool for monitoring some ecologically important Amazonian animals, and especially those in protected areas. © 2011 Springer Science+Business Media B.V. Source

Milliken W.,HLAA | Zappi D.,HLAA | Sasaki D.,Fundacao Ecologica Cristalino | Hopkins M.,National Institute of Amazonian Research | Pennington R.T.,Royal Botanic Garden
Kew Bulletin

Summary: In spite of the existence of a vast body of information on the plant diversity of the Amazon, there remain significant obstacles to informed decision-making and management for conservation. Species distributions are poorly understood and the relationships between diversity and composition of vegetation, ecosystem services and resilience to climatic fluctuations are insufficiently clear. The geographic distribution of phylogenetic diversity in relation to current protected areas is unexplored and very little is known about intraspecific genetic variability and its practical significance. Interpretation of vegetation differentiation and distribution remains relatively simplistic; there are still large parts of the basin for which few or no botanical data exist, and many rare and sparsely distributed species remain undiscovered. Improved understanding of the ecological roles, dynamics and associations of the species of greatest importance for the maintenance of sustainable livelihoods and ecosystem services, habitat restoration and adaptation to climate change is a high priority. In many cases these are common and widespread species. Some of these issues are explored by looking at the Cristalino region in northern Mato Grosso as a case-study. Effective integration, quality assessment, synthesis and application of existing data on the plant diversity of the Amazon will help to address these issues. However, more targeted information is needed from the ground. Future prioritisation of research effort will require a careful and pragmatic balance between the 'traditional' focus on rare and endemic species and species-rich communities, and the growing need to understand the key 'framework' elements that will determine the future of the Amazon environment. Similar situations are faced elsewhere in the tropics: for botanical research institutes in the 21st century this demands an urgent re-evaluation of core activities and concerted engagement with the issues and challenges facing conservation in a context of rampant population growth, climate change and environmental destruction. © 2011 The Board of Trustees of the Royal Botanic Gardens, Kew. Source

Veenendaal E.M.,Wageningen University | Torello-Raventos M.,James Cook University | Feldpausch T.R.,University of Leeds | Domingues T.F.,University of Edinburgh | And 49 more authors.

Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation. Herbaceous layer cover declined as woody cover increased. This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna-forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 0.1 m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America. Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna-forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, consistent across all three continents coexistence was found to be confined to a well-defined edaphic-climate envelope with soil and climate the key determinants of the relative location of forest and savanna stands. Moreover, when considered in conjunction with the appropriate water availability metrics, it emerges that soil exchangeable cations exert considerable control on woody canopy-cover extent as measured in our pan-continental (forest + savanna) data set. Taken together these observations do not lend support to the notion of alternate stable states mediated through fire feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands. © Author(s) 2015. Source

Torello-Raventos M.,James Cook University | Torello-Raventos M.,University of Leeds | Feldpausch T.R.,University of Leeds | Veenendaal E.,Wageningen University | And 46 more authors.
Plant Ecology and Diversity

Background: There is no generally agreed classification scheme for the many different vegetation formation types occurring in the tropics. This hinders cross-continental comparisons and causes confusion as words such as 'forest' and 'savanna' have different meanings to different people. Tropical vegetation formations are therefore usually imprecisely and/or ambiguously defined in modelling, remote sensing and ecological studies.Aims: To integrate observed variations in tropical vegetation structure and floristic composition into a single classification scheme.Methods: Using structural and floristic measurements made on three continents, discrete tropical vegetation groupings were defined on the basis of overstorey and understorey structure and species compositions by using clustering techniques.Results: Twelve structural groupings were identified based on height and canopy cover of the dominant upper stratum and the extent of lower-strata woody shrub cover and grass cover. Structural classifications did not, however, always agree with those based on floristic composition, especially for plots located in the forest-savanna transition zone. This duality is incorporated into a new tropical vegetation classification scheme.Conclusions: Both floristics and stand structure are important criteria for the meaningful delineation of tropical vegetation formations, especially in the forest/savanna transition zone. A new tropical vegetation classification scheme incorporating this information has been developed. © 2013 Copyright 2013 Botanical Society of Scotland and Taylor & Francis. Source

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