Santa Cruz de la Sierra, Bolivia
Santa Cruz de la Sierra, Bolivia

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Putz F.E.,University of Florida | Putz F.E.,University Utrecht | Zuidema P.A.,University Utrecht | Zuidema P.A.,Wageningen University | And 11 more authors.
Conservation Letters | Year: 2012

Most tropical forests outside protected areas have been or will be selectively logged so it is essential to maximize the conservation values of partially harvested areas. Here we examine the extent to which these forests sustain timber production, retain species, and conserve carbon stocks. We then describe some improvements in tropical forestry and how their implementation can be promoted. A simple meta-analysis based on >100 publications revealed substantial variability but that: timber yields decline by about 46% after the first harvest but are subsequently sustained at that level; 76% of carbon is retained in once-logged forests; and, 85-100% of species of mammals, birds, invertebrates, and plants remain after logging. Timber stocks will not regain primary-forest levels within current harvest cycles, but yields increase if collateral damage is reduced and silvicultural treatments are applied. Given that selectively logged forests retain substantial biodiversity, carbon, and timber stocks, this "middle way" between deforestation and total protection deserves more attention from researchers, conservation organizations, and policy-makers. Improvements in forest management are now likely if synergies are enhanced among initiatives to retain forest carbon stocks (REDD+), assure the legality of forest products, certify responsible management, and devolve control over forests to empowered local communities. © 2012 Wiley Periodicals, Inc.


Markesteijn L.,Wageningen University | Markesteijn L.,Instituto Boliviano Of Investigacion Forestal Ibif | Poorter L.,Wageningen University | Poorter L.,Instituto Boliviano Of Investigacion Forestal Ibif | And 3 more authors.
New Phytologist | Year: 2011

Plant hydraulic architecture has been studied extensively, yet we know little about how hydraulic properties relate to species' life history strategies, such as drought and shade tolerance. The prevailing theories seem contradictory. We measured the sapwood (Ks) and leaf (Kl) hydraulic conductivities of 40 coexisting tree species in a Bolivian dry forest, and examined associations with functional stem and leaf traits and indices of species' drought (dry-season leaf water potential) and shade (juvenile crown exposure) tolerance. Hydraulic properties varied across species and between life-history groups (pioneers vs shade-tolerant, and deciduous vs evergreen species). In addition to the expected negative correlation of Kl with drought tolerance, we found a strong, negative correlation between Kl and species' shade tolerance. Across species, Ks and Kl were negatively correlated with wood density and positively with maximum vessel length. Consequently, drought and shade tolerance scaled similarly with hydraulic properties, wood density and leaf dry matter content. We found that deciduous species also had traits conferring efficient water transport relative to evergreen species. Hydraulic properties varied across species, corresponding to the classical trade-off between hydraulic efficiency and safety, which for these dry forest trees resulted in coordinated drought and shade tolerance across species rather than the frequently hypothesized trade-off. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.


Markesteijn L.,Wageningen University | Markesteijn L.,Instituto Boliviano Of Investigacion Forestal Ibif | Poorter L.,Wageningen University | Poorter L.,Instituto Boliviano Of Investigacion Forestal Ibif | And 3 more authors.
Plant, Cell and Environment | Year: 2011

Cavitation resistance is a critical determinant of drought tolerance in tropical tree species, but little is known of its association with life history strategies, particularly for seasonal dry forests, a system critically driven by variation in water availability. We analysed vulnerability curves for saplings of 13 tropical dry forest tree species differing in life history and leaf phenology. We examined how vulnerability to cavitation (P50) related to dry season leaf water potentials and stem and leaf traits. P50-values ranged from -0.8 to -6.2 MPa, with pioneers on average 38% more vulnerable to cavitation than shade-tolerants. Vulnerability to cavitation was related to structural traits conferring tissue stress vulnerability, being negatively correlated with wood density, and surprisingly maximum vessel length. Vulnerability to cavitation was negatively related to the Huber-value and leaf dry matter content, and positively with leaf size. It was not related to SLA. We found a strong trade-off between cavitation resistance and hydraulic efficiency. Most species in the field were operating at leaf water potentials well above their P50, but pioneers and deciduous species had smaller hydraulic safety margins than shade-tolerants and evergreens. A trade-off between hydraulic safety and efficiency underlies ecological differentiation across these tropical dry forest tree species. © 2010 Blackwell Publishing Ltd.


Poorter L.,Wageningen University | Poorter L.,Instituto Boliviano Of Investigacion Forestal Ibif | McDonald I.,Wageningen University | Alarcon A.,Instituto Boliviano Of Investigacion Forestal Ibif | And 7 more authors.
New Phytologist | Year: 2010

In a comparative study of 42 rainforest tree species we examined relationships amongst wood traits, diameter growth and survival of large trees in the field, and shade tolerance and adult stature of the species. The species show two orthogonal axes of trait variation: a primary axis related to the vessel size-number trade-off (reflecting investment in hydraulic conductance vs hydraulic safety) and a secondary axis related to investment in parenchyma vs fibres (storage vs strength). Across species, growth rate was positively related to vessel diameter and potential specific hydraulic conductance (K p), and negatively related to wood density. Survival rate was only positively related to wood density. Light-demanding species were characterized by low wood and vessel density and wide vessels. Tall species were characterized by wide vessels with low density and large Kp. Hydraulic traits were more closely associated with adult stature than with light demand, possibly because tall canopy species experience more drought stress and face a higher cavitation risk. Vessel traits affect growth and wood density affects growth and survival of large trees in the field. Vessel traits and wood density are therefore important components of the performance and life history strategies of tropical tree species. © 2009 New Phytologist.


Sterck F.,Wageningen University | Markesteijn L.,Wageningen University | Markesteijn L.,CSIC - National Museum of Natural Sciences | Toledo M.,Instituto Boliviano Of Investigacion Forestal Ibif | And 3 more authors.
Ecology | Year: 2014

Niche differentiation is a major hypothesized determinant of species distributions, but its practical importance is heavily debated and its underlying mechanisms are poorly understood. Trait-based approaches have been used to infer niche differentiation and predict species distributions. For understanding underlying mechanisms, individual traits should be scaled up to whole-plant performance, which has rarely been done. We measured seven key traits that are important for carbon and water balance for 37 tropical tree species. We used a process-based plant physiological model to simulate the carbon budget of saplings along gradients of light and water availability, and quantified the performance of the species in terms of their light compensation points (a proxy for shade tolerance), water compensation points (proxy for drought tolerance), and maximum carbon gain rates (proxy for potential growth rate). We linked species performances to their observed distributions (the realized niches) at two spatial scales in Bolivian lowland forests: along a canopy openness gradient at local scale (∼1 km2) and along a rainfall gradient (1100-2200 mm/yr) at regional (∼1000 km) scale. We show that the water compensation point was the best predictor of species distributions along water and light resource gradients within and across tropical forests. A sensitivity analysis suggests that the stomatal regulation of minimum leaf water potentials, rather than stem hydraulic traits (sapwood area and specific conductivity), contributed to the species differences in the water compensation point of saplings. The light compensation point and maximum carbon gain, both driven by leaf area index and leaf nitrogen concentration, also contributed to differential species distributions at the local scale, but not or only marginally at the regional scale. Trait-and-physiology-based simulations of whole-plant performance thus help to evaluate the possible roles of individual traits in physiological processes underlying species performance along environmental gradients. The development of such whole-plant concepts will improve our ability to understand responses of plant communities to shifts in resource availability and stress under global change. © 2014 by the Ecological Society of America.


Poorter L.,Wageningen University | Poorter L.,Instituto Boliviano Of Investigacion Forestal Ibif | Kitajima K.,University of Florida | Kitajima K.,Smithsonian Tropical Research Institute | And 4 more authors.
Ecology | Year: 2010

Resprouting is an important persistence strategy for woody species and represents a dominant pathway of regeneration in many plant communities, with potentially large consequences for vegetation dynamics, community composition, and species coexistence. Most of our knowledge of resprouting strategies comes from fire-prone systems, but this cannot be readily applied to other systems where disturbances are less intense. In this study we evaluated sapling responses to stem snapping for 49 moist-forest species and 36 dry-forest species from two Bolivian tropical forests. To this end we compared in a field experiment the survival and height growth of clipped and control saplings for a two-year period, and related this to the shade tolerance, carbohydrate reserves, and the morphological traits (wood density, leaf size) of the species. Nearly all saplings resprouted readily after stem damage, although dry-forest species realized, on average, a better survival and growth after stem damage compared to moist-forest species. Shade-tolerant species were better at resprouting than light-demanding species in moist forest. This resprouting ability is an important prerequisite for successful regeneration in the shaded understory, where saplings frequently suffer damage from falling debris. Survival after stem, damage was, surprisingly, only modestly related to stem reserves, and much more strongly related to wood density, possibly because a high wood density enables plants to resist fungi and pathogens and to reduce stem decay. Correlations between sapling performance and functional traits were similar for the two forest types, and for phylogenetically independent contrasts and for cross-species analyses. The consistency of these results suggests that tropical forest species face similar trade-offs in different sites and converge on similar sets of solutions. A high resprouting ability, as well as investments in stem defense and storage reserves, form part of a suite of co-evolved traits that underlies the growth-survival trade-off, and contributes to light gradient partitioning and species coexistence. These links with shade tolerance are important in the moist evergreen forest, which casts a deep, more persistent shade, but tend to diminish in dry deciduous forest where light is a less limiting resource. © 2010 by the Ecological Society ot America.


Poorter L.,Wageningen University | Poorter L.,Instituto Boliviano Of Investigacion Forestal Ibif | Mcneil A.,Instituto Boliviano Of Investigacion Forestal Ibif | Mcneil A.,Ferrum College | And 4 more authors.
Functional Ecology | Year: 2014

Bark is crucial to trees because it protects their stems against fire and other hazards and because of its importance for assimilate transport, water relationships and repair. We evaluate size-dependent changes in bark thickness for 50 woody species from a moist forest and 50 species from a dry forest in Bolivia and relate bark thickness to their other bark characteristics, species life-history strategies and wood properties. For 71% of the evaluated species, the allometric coefficient describing the relationship between bark thickness and stem diameter was significantly <1 (average 0·74; range 0·38-1·20), indicating that species attain an absolute increase in bark thickness with increasing stem diameter but invest relatively less in bark thickness at larger diameters. We hypothesized that in response to more frequent fires, dry-forest species should have thicker barked trees. Contrary to this prediction, dry- and moist-forest tree species were similar in allometric bark coefficients and bark thickness. In both forest types, about 50% of the species never developed bark thick enough to avoid fire damage to their vascular cambia. Recent increases in fire frequency and extent may therefore have potentially large effects on the composition of these forests. Within each forest, coexisting species displayed a diversity of bark investment strategies, and bark thickness of trees 40 cm stem diameter varied up to 15-fold across species (ranging from 1·7 to 25·7 mm). In both forests, sapling bark thickness was positively related to adult stature (maximum height) of the species, possibly because trees of long-lived species are more likely to experience fire during their life span, whereas for species that are characteristically small or short-lived, it may not pay off to invest heavily in bark and they may follow a resprouter strategy instead. Sapling bark thickness was not related to species' shade tolerance. Bark and wood traits were closely associated, showing a trade-off between species with tough tissues (high densities of bark and wood) on the one hand vs. species with watery tissues (high water contents of bark and wood) and thick bark on the other hand. Species with different bark investment strategies coexist in both the moist and the dry tropical forest studied. Bark and wood fulfil many functions, and the observed trade-offs may reflect different plant strategies to deal with fire, avoidance and repair of stem damage, avoidance and resistance of drought stress, and mechanical stability. © 2013 The Authors. Functional Ecology © 2013 British Ecological Society.


Mendivelso H.A.,CSIC - Pyrenean Institute of Ecology | Mendivelso H.A.,University of Barcelona | Mendivelso H.A.,Instituto Boliviano Of Investigacion Forestal Ibif | Camarero J.J.,University of Barcelona | And 4 more authors.
Agricultural and Forest Meteorology | Year: 2014

We analyzed the effects of climate and drought on radial growth using dendrochronology in seven deciduous tree species coexisting in a Bolivian tropical dry forest subjected to seasonal drought. Precipitation, temperature and a multiscalar drought index were related to tree-ring width data at different time-scales (from one month to 42 years). Precipitation affected positively tree growth in all species, mainly during the wet season, while temperature affected it negatively in five species. Tree growth responses to precipitation and temperature were species-specific and peaked at short-time scales, specifically from one to nine months. At inter-annual scales tree growth always responded positively to less dry conditions at short-time scales, particularly from two to seven months, and also at long-time scales from six to 30 years. Tree growth was mainly sensitive to multi-annual droughts and such sensitivity differed among species. Our findings suggest that tree species of the studied tropical dry forest are predominantly sensitive in terms of growth reduction to long-lasting droughts. This time-dependency of growth responses to drought should be explicitly considered as an additional constraint of the community dynamics in evaluations of the future responses of tropical dry forests to climate warming. © 2014 .


Carreno-Rocabado G.,Wageningen University | Carreno-Rocabado G.,Instituto Boliviano Of Investigacion Forestal Ibif | Pena-Claros M.,Wageningen University | Pena-Claros M.,Instituto Boliviano Of Investigacion Forestal Ibif | And 5 more authors.
Journal of Ecology | Year: 2012

Disturbances are widespread and may affect community assembly, species composition, (functional) diversity and hence ecosystem processes. It remains still unclear to what extent disturbance-mediated species changes scale-up to changes in community functional properties, especially for species-rich tropical forests. A large-scale field experiment was performed in which the dynamics of 15 000 stems >10 cm in diameter was monitored for 8 years in 44 one-ha forest plots. Twelve functional effect and response traits were measured for the most dominant tree species. The effects of different intensities of disturbance caused by logging and silvicultural treatments on the species and functional diversity of a Bolivian tropical forest community were evaluated, along with how these changes were driven by underlying demographic processes. Disturbance treatments did not affect species diversity or functional diversity indices based on multiple traits related to primary productivity and decomposition rate. This result suggests that species richness is conserved, and trait variation is maintained, which can buffer the community against environmental change. In contrast, disturbance intensity affected the average plant trait values in the community (the community-weighted mean) for seven of 12 traits evaluated. At high disturbance intensity, the community had a lower wood density of stem and branches, lower leaf toughness and dry matter content, but higher specific leaf area and leaf N- and P concentration, with the value of these traits changing on average 6% over the 8-year period. The functional spectrum of the community changed, therefore, from 'slow', conservative, shade-tolerant species towards 'fast', acquisitive, light-demanding species. These functional changes in mean trait values may enhance primary productivity and decomposition rate in the short term. Temporal changes in community functional properties were mainly driven by recruitment, and little by mortality or survival. Synthesis. Moderate levels of (logging) disturbance neither affected species diversity nor functional diversity per se in the 8-year period after logging. Disturbance did, however, change the functional community composition towards 'fast' species with more acquisitive traits, thus potentially fuelling primary productivity and nutrient and carbon cycling. In conclusion, tropical forest management may contribute to conserving functional biodiversity of trees while providing forest resources. © 2012 The Authors. Journal of Ecology © 2012 British Ecological Society.


Toledo M.,Wageningen University | Toledo M.,Instituto Boliviano Of Investigacion Forestal | Toledo M.,Instituto Boliviano Of Investigacion Forestal Ibif | Pena-Claros M.,Wageningen University | And 9 more authors.
Journal of Ecology | Year: 2012

1. The analysis of species distribution patterns along environmental gradients is important for understanding the diversity and ecology of plants and species responses to climate change, but detailed data are surprisingly scarce for the tropics. 2. Here, we analyse the distribution of 100 woody species over 220 1-ha forest plots distributed over an area of c. 160000km 2, across large environmental gradients in lowland Bolivia and evaluate the relative importance of climate and soils in shaping species distribution addressing four multivariate environmental axes (rainfall amount and distribution, temperature, soil fertility and soil texture). 3. Although species abundance was positively related to species frequency (the number of plots in which the species is found), this relationship was rather weak, which challenges the view that most tropical forests are dominated at large scales by a few common species. 4. Species responded clearly to environmental gradients, and for most of the species (65%), climatic and soil conditions could explain most of the variation in occurrence (R 2>0.50), which challenges the idea that most tropical tree species are habitat generalists. 5. Climate was a stronger driver of species distribution than soils; 91% of the species were affected by rainfall (distribution), 72% by temperature, 47% by soil fertility and 44% by soil texture. In contrast to our expectation, few species showed a typical unimodal response to the environmental gradients. 6. Synthesis. Tropical tree species specialize for different parts of the environmental gradients, and climate is a stronger driver of species distribution than soils. Because climate change scenarios predict increases in annual temperature and a stronger dry season for tropical forests, we may expect potentially large shifts in the distribution of tropical trees. © 2011 The Authors. Journal of Ecology © 2011 British Ecological Society.

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