Browsing by Autor "Marisol Toledo"

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Abiotic and biotic drivers of biomass change in a Neotropical forest
(Wiley, 2017) Masha T. van der Sande; Marielos Peña‐Claros; Nataly Ascarrunz; E.J.M.M. Arets; Juan Carlos Licona; Marisol Toledo; Lourens Poorter
Summary Tropical forests play an important role in the global carbon cycle, but the drivers of net forest biomass change (i.e. net carbon sequestration) are poorly understood. Here, we evaluate how abiotic factors (soil conditions and disturbance) and biotic factors (forest structure, diversity and community trait composition) shape three important demographic processes (biomass recruitment, growth and mortality) and how these underlie net biomass change. To test this, we evaluated 9 years of biomass dynamics using 48 1‐ha plots in a Bolivian tropical moist forest, and measured for the most abundant species eight functional traits that are important for plant carbon gain and loss. Demographic processes were related to the abiotic and biotic factors using structural equation models. Variation in net biomass change across plots was mostly due to stand‐level mortality, but mortality itself could not be predicted at this scale. Contrary to expectations, we found that species richness and trait composition – which is an indicator for the mass‐ratio theory – had little effect on the demographic processes. Biomass recruitment (i.e. the biomass growth by recruiting trees) increased with higher resource availability (i.e. water and light) and with high species richness, probably because of increased resource use efficiency. Biomass growth of larger, established trees increased with higher sand content, which may facilitate root growth of larger trees to deeper soil layers. In sum, diversity and mass‐ratio are of limited importance for the productivity of this forest. Instead, in this moist tropical forest with a marked dry season, demographic processes are most strongly determined by soil texture, soil water availability and forest structure. Only by simultaneously evaluating multiple abiotic and biotic drivers of demographic processes, better insights can be gained into mechanisms playing a role in the carbon sequestration potential of tropical forests and natural systems in general.
Adjusting xylem anatomy and growth to inter-annual climate variability in two Fabaceae species (Centrolobium microchaete, Cenostigma pluviosum) from Bolivian dry tropical forests
(Elsevier BV, 2021) Ana I. García‐Cervigón; Luz Natalia Mercado; Hooz A. Mendivelso; Marisol Toledo; J. Julio Camarero
Amazonian Dark Earth Shapes the Understory Plant Community in a Bolivian Forest
(Wiley, 2015) Estela Quintero‐Vallejo; Yannick Klomberg; Frans Bongers; Lourens Poorter; Marisol Toledo; Marielos Peña‐Claros
Abstract Amazonian Dark Earths ( ADE ) are the result of human modification of the Amazonian landscape since pre‐Columbian times. ADE are characterized by increased soil fertility compared to natural soils. In the Amazonian forest, soil fertility influences understory herb and fern species composition. However, little research has been done to evaluate the effect of ADE on the composition of the understory community. We evaluated the effects of ADE and soil in 36 plots (150 m × 4 m) established in a Bolivian moist forest (La Chonta). For each plot, we determined soil nutrients, and the composition, richness, and abundance of terrestrial fern, angiosperm herb, and understory palm species. We found that the presence of ADE created a gradient in soil nutrients and pH that affected the understory species composition especially of ferns and palms. Additionally, the higher nutrient concentration and more neutral soil pH on ADE soils caused a decrease of ferns species richness. We therefore conclude that the current composition of the understory community in this particular Bolivian forest is a reflection of past human modifications of the soil.
Climate and soil drive forest structure in Bolivian lowland forests
(Cambridge University Press, 2011) Marisol Toledo; Lourens Poorter; Marielos Peña‐Claros; Alfredo Alarcón; Julio Balcázar; Claudio Leaño; Juan Carlos Licona; Frans Bongers
Abstract: Climate is one of the most important factors determining variation in forest structure, but whether soils have independent effects is less clear. We evaluate how climate and soil independently affect forest structure, using 89 200 stems ≥ 10 cm dbh from 220 1-ha permanent plots distributed along environmental gradients in lowland Bolivia. Fifteen forest structural variables, related to vertical structure (forest height and layering), horizontal structure (basal area, median and the 99th percentile of the stem diameter and size-class distribution) and density of life forms (tree, palm and liana), were evaluated. Environmental variables were summarized in four multivariate axes, related to rainfall, temperature, soil fertility and soil texture. Multiple regression indicates that all structural variables were affected by one or more of the environmental axes, but the explained variation was generally low (median R 2 = 0.15). Rainfall and soil texture affected most forest structural variables (respectively 87% and 80%) and had qualitatively similar effects. This suggests that plant water availability, as determined by rainfall and soil water retention capacity, is the strongest driver of forest structure, whereas soil fertility was a weaker driver of forest structure, affecting 53% of the variables. Maximum forest height, palm density, total basal area and liana infestation showed the strongest responses to environmental variation (with R 2 ranging from 0.31–0.82). Forest height, palm density and total basal area increased with plant water availability, while liana infestation decreased with plant water availability. Therefore, multiple rather than single environmental factors must be used to explain the structure of tropical forests.
Climate is a stronger driver of tree and forest growth rates than soil and disturbance
(Wiley, 2010) Marisol Toledo; Lourens Poorter; Marielos Peña‐Claros; Alfredo Alarcón; Julio Balcázar; Claudio Leaño; Juan Carlos Licona; Oscar Llanque; Vincent Vroomans; Pieter A. Zuidema
Summary 1. Essential resources such as water, nutrients and light vary over space and time and plant growth rates are expected to vary accordingly. We examined the effects of climate, soil and logging disturbances on diameter growth rates at the tree and stand level, using 165 1‐ha permanent sample plots distributed across Bolivian tropical lowland forests. 2. We predicted that growth rates would be higher in humid than in dry forests, higher in nutrient‐rich than nutrient‐poor forests and higher in logged than non‐logged forests. 3. Across the 165 plots we found positive basal area increases at the stand level, which agree with the generally reported biomass increases in tropical forests. 4. Multiple regression analysis demonstrated that climate variables, in particular water availability, were the strongest drivers of tree growth. More rainfall, a shorter and less intense dry period and higher temperatures led to higher tree growth rates. 5. Tree growth increased modestly with soil fertility and basal area growth was greatest at intermediate soil fertility. Surprisingly, tree growth showed little or no relationship with total soil nitrogen or plant available soil phosphorus. 6. Growth rates increased in logged plots just after logging, but this effect disappeared after 6 years. 7. Synthesis . Climate is the strongest driver of spatial variation in tree growth, and climate change may therefore have large consequences for forest productivity and carbon sequestration. The negative impact of decreased rainfall and increased rainfall seasonality on tree growth might be partly offset by the positive impact of increased temperature in these forests.
Composición florística y usos de bosques secundarios en la provincia Guarayos, Santa Cruz, Bolivia
(2005) Marisol Toledo; B Salick; Bette A. Loiselle; Peter M. Jørgensen
Differential Growth Responses to Water Balance of Coexisting Deciduous Tree Species Are Linked to Wood Density in a Bolivian Tropical Dry Forest
(Public Library of Science, 2013) Hooz A. Mendivelso; J. Julio Camarero; Oriol Royo Obregón; Emília Gutiérrez; Marisol Toledo
A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.
Distribution patterns of tropical woody species in response to climatic and edaphic gradients
(Wiley, 2011) Marisol Toledo; Marielos Peña‐Claros; Frans Bongers; Alfredo Alarcón; Julio Balcázar; José Chuviña; Claudio Leaño; Juan Carlos Licona; Lourens Poorter
Summary 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. 160 000 km 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.
Driving factors of forest growth: a reply to Ferry <i>et al.</i> (2012)
(Wiley, 2012) Marisol Toledo; Lourens Poorter; Marielos Peña‐Claros; Alfredo Alarcón; Julio Balcázar; Claudio Leaño; Juan Carlos Licona; Oscar Llanque; Vincent Vroomans; Pieter A. Zuidema
Summary 1. In a recent paper, we analysed the effects of climate, soil and logging disturbance on tree and forest growth (Toledo et al. 2011a). We took advantage of one of the largest data sets in the Neotropics, consisting of 165 1‐ha plots and over 62 000 trees distributed over an area of c. 160 000 km 2 , across large environmental gradients in lowland Bolivia. The main findings were that climate was the strongest driver of spatial variation in tree growth, whereas soils had only a modest effect on growth and that the effect of logging disappeared after a few years. 2. Ferry et al. (2012) suggest that we underestimated the disturbance effects on growth because of a supposedly wrong coding of Time After Logging (TAL) for unlogged plots. Although we have good biological reasons why we coded TAL like we did, we checked Ferry et al. ’s suggestions for recoding and found no differences in variables that significantly explained tree and forest growth. We agree, however, that for future research, it is important to go beyond simple descriptors such as time after logging and basal area logged, to better describe the variation in logging impact found in areas under forest management. 3. Ferry et al. claim that we did not define basal area growth properly. We believe this is a semantic issue, as we clearly defined basal area growth as the net change in basal area. This net basal area change in Bolivian forests is indeed relatively high compared to other studies, which may be attributed to the higher soil fertility and biogeographic differences in species composition and their traits. 4. Synthesis . Many apparent discrepancies in the ecological literature arise because tropical forest ecologists tend to see the world from the perspective of their ‘own’ forest (despite clear biogeographic differences) and try to capture the same ecological processes using different variables and measurement protocols. To advance our understanding and go beyond single‐case studies, we need to assemble large databases, quantify forest dynamics and disturbances in similar ways, be aware of differences among forests and analyse environmental dose–response curves.
Efecto de la pérdida de cobertura natural sobre la flora endémica del Área Tropical Importante para Plantas (TIPA) Concepción (Santa Cruz, Bolivia)
(Universidade Federal de Goiás, 2022) Scarlet Jazmin Quiroga-Méndez; Oriana Anyhely Lino-Villalba; Liliana Arroyo-Herbas; Marisol Toledo; Maira T. Martinez-Ugarteche; Jean Carla Montero Aramayo; Bente Klitgaard; Daniel Villarroel Segarra
En el presente estudio se inventarió la riqueza de taxones endémicos que habitan en el Área Tropical Importante para Plantas (TIPA) Concepción, así como el efecto de la pérdida de la cobertura natural sobre estos atributos florísticos. El inventario fue realizado mediante fuentes de datos primarios (prospecciones de campo) y secundarios (bases de datos y especímenes de herbarios). La pérdida de la cobertura vegetal fue determinada mediante el análisis multitemporal de imágenes satelitales de tres periodos de tiempo (1990-2000, 2001-2010, 2011-2020). Basados en los registros históricos e inventarios de campo, un total de 28 taxones endémicos fueron inventariados (dos son nuevas especies para la ciencia). El endemismo que resguardan los hábitats que conforman el paisaje del área de estudio resultó distinto cuando comparados unos con otros (<30% de similaridad). Hasta el 2020, la cobertura natural se redujo progresivamente al 72.6%, bajo una tasa de pérdida anual de 0,88% ± 0,27%. Como consecuencia de la pérdida de la cobertura vegetal, ocho de los 28 taxones endémicos han desaparecido en la TIPA Concepción, ya que los hábitats donde fueron registrados se sustituyeron por áreas de producción agropecuaria. Por lo cual, los taxones remanentes enfrentan un alto riesgo de extinción local.
Effects of Amazonian Dark Earths on growth and leaf nutrient balance of tropical tree seedlings
(Springer Science+Business Media, 2015) Estela Quintero‐Vallejo; Marielos Peña‐Claros; Frans Bongers; Marisol Toledo; Lourens Poorter
Environmental heterogeneity and dispersal processes influence post-logging seedling establishment in a Chiquitano dry tropical forest
(Elsevier BV, 2015) Robin Corrià-Ainslie; J. Julio Camarero; Marisol Toledo
Estructura forestal y regeneración natural de poblaciones del pino de monte (Podocarpus parlatorei Pilg.) en el Departamento de Santa Cruz, Bolivia
(2022) Romel E. Nina Churqui; Marco Aurelio Pinto-Viveros; Jhoselin Sánchez; Liliana Arroyo-Herbas; Diego Espinoza; Erwin Banegas; Sergio Iván Mota Pantoja; Marisol Toledo
El pino de monte (Podocarpus parlatorei Pilg.) es endémico de los bosques montanos australes. A lo largo de la historia fue sobreexplotado con fines maderables y actualmente se encuentra en peligro de extinción. En Bolivia existen vacíos de información con respecto a su estructura y dinámica poblacional. En este estudio describimos su estructura forestal (individuos adultos, ‘10 cm de diámetro) y su regeneración (individuos jóvenes, <10 cm) en el complejo de pinares boliviano-tucumano del Departamento de Santa Cruz (Bolivia). Se evaluaron 16 localidades en los municipios de Vallegrande, Postrer Valle, Pucara y Quirusillas (81 parcelas de muestreo). Las densidades (individuos/ha) de estructura y regeneración se contrastaron entre municipios y categorías diamétricas (pruebas de Kruskal-Wallis), y se analizó la asociación de ambas variables entre sí y con la elevación, la pendiente y la cobertura arbórea (correlaciones de Spearman). La estructura forestal fue clasificada en cinco categorías diamétricas y se distribuyó en forma de J invertida. Vallegrande presentó la mayor densidad (650 individuos/ha), superior a lo determinado para el paisaje en general (200 individuos/ha). La regeneración, entre sus cuatro categorías diamétricas, también presentó una distribución de J invertida; la mayor regeneración se cuantificó en Pucara (1700 individuos/ha), que superó lo registrado a nivel paisaje (1100 individuos/ha). Sólo tres variables mostraron asociaciones significativas (P<0.05). La elevación (ρ=0.23) y la cobertura arbórea (ρ=0.43) se relacionaron de forma positiva con la estructura forestal, mientras que la regeneración lo hizo negativamente (ρ=-0.30). La estructura forestal y la regeneración natural de las poblaciones del pino de monte revelaron que la especie está distante de presentar un buen estado se conservación.
Examining the sustainability and development challenge in agricultural-forest frontiers of the Amazon Basin through the eyes of locals
(2019) Irene Blanco‐Gutiérrez; Rhys Manners; Consuelo Varela‐Ortega; Ana M. Tarquís; Lucieta Guerreiro Martorano; Marisol Toledo
Abstract. The Amazon basin is the world’s largest rainforest and the most biologically diverse place on Earth. Despite the critical importance of this region, Amazon forests continue inexorably to be degraded and deforested for various reasons, mainly a consequence of agricultural expansion. The development of novel policy strategies that provide balanced solutions, associating economic growth and environmental protection, is still challenging, largely because the perspective of those most affected- local stakeholders- is often ignored. Participatory Fuzzy Cognitive Mapping (FCM) was implemented to examine stakeholder perceptions towards the sustainable development of two agricultural-forest frontier areas in the Bolivian and Brazilian Amazon. A series of development scenarios and a climate change scenario were explored and applied to stakeholder derived FCM. Stakeholders in both regions perceived landscapes of socio-economic impoverishment and environmental degradation driven by governmental and institutional deficiencies. Under such abject conditions, governance and well-integrated social and technological strategies offered socio-economic development, environmental conservation, and resilience to climatic changes. The results suggest the benefits of a new type of thinking for development strategies in the Amazon basin, and that continued application of traditional development policies reduce the resilience of the Amazon to climate change, whilst limiting socio-economic development and environmental conservation.
Examining the sustainability and development challenge in agricultural-forest frontiers of the Amazon Basin through the eyes of locals
(Copernicus Publications, 2020) Irene Blanco‐Gutiérrez; Rhys Manners; Consuelo Varela‐Ortega; Ana M. Tarquís; Lucieta Guerreiro Martorano; Marisol Toledo
Abstract. The Amazon basin is the world's largest rainforest and the most biologically diverse place on Earth. Despite the critical importance of this region, Amazon forests continue inexorably to be degraded and deforested for various reasons, mainly a consequence of agricultural expansion. The development of novel policy strategies that provide balanced solutions, associating economic growth with environmental protection, is still challenging, largely because the perspective of those most affected – local stakeholders – is often ignored. Participatory fuzzy cognitive mapping (FCM) was implemented to examine stakeholder perceptions towards the sustainable development of two agricultural-forest frontier areas in the Bolivian and Brazilian Amazon. A series of development scenarios were explored and applied to stakeholder-derived FCM, with climate change also analysed. Stakeholders in both regions perceived landscapes of socio-economic impoverishment and environmental degradation driven by governmental and institutional deficiencies. Under such abject conditions, governance and well-integrated social and technological strategies offered socio-economic development, environmental conservation, and resilience to climatic changes. The results suggest there are benefits of a new type of thinking for development strategies in the Amazon basin and that continued application of traditional development policies reduces the resilience of the Amazon to climate change, whilst limiting socio-economic development and environmental conservation.
Fires scorching Bolivia's Chiquitano forest
(American Association for the Advancement of Science, 2019) Alfredo Romero‐Muñoz; Martin Jansen; Angela M. Nuñez; Marisol Toledo; Roberto Vides Almonacid; Tobias Kuemmerle
Patterns and Determinants of Floristic Variation across Lowland Forests of Bolivia
(Wiley, 2010) Marisol Toledo; Lourens Poorter; Marielos Peña‐Claros; Alfredo Alarcón; Julio Balcázar; José Chuviña; Claudio Leaño; Juan Carlos Licona; Hans ter Steege; Frans Bongers
Floristic variation is high in the Neotropics, but little is known about the factors shaping this variation at the mesoscale. We examined floristic composition and its relationship with environmental factors across 220 1-ha permanent plots in tropical lowland Bolivia. For each plot, abundance of 100 species (93 tree and 7 palm species ≥10 cm diam) was obtained. Climatic data, related to rainfall seasonality and temperature, were interpolated from all available weather stations in the region, and soil properties, related to texture and fertility, were obtained for each plot. Floristic variation was strongly associated with differences in water availability and temperature, and therefore the climatic gradient shaped floristic variation more strongly than the edaphic gradient. Detrended correspondence analysis ordination divided lowland Bolivia primarily into two major groups (Southern Chiquitano region vs. the Amazon region) and a multiple response permutation procedure distinguished five floristic regions. Overall, the tested environmental variables differed significantly among the five regions. Using indicator species analysis, we distinguished 82 strong indicator species, which had significant environmental preferences for one floristic region. These species can be used as indicators of environmental conditions or to determine which floristic region a certain forest belongs. Given the predicted decreases in rainfall and increases in temperature for tropical lowland forests, our gradient approach suggests that species composition may shift drastically with climate change. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.
Post-fire tree regeneration in lowland Bolivia: implications for fire management
(Elsevier BV, 2002) Kevin Gould; Todd S. Fredericksen; F. J. Morales; Deborah Kennard; Francis E. Putz; Bonifacio Mostacedo; Marisol Toledo
Sapling performance along resource gradients drives tree species distributions within and across tropical forests
(Wiley, 2014) Frank J. Sterck; Lars Markesteijn; Marisol Toledo; F. Schieving; Lourens Poorter
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 km 2 ) 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.
Secondary Succession and Indigenous Management in Semideciduous Forest Fallows of the Amazon Basin<sup>1</sup>
(Wiley, 2005) Marisol Toledo; Jan Salick
ABSTRACT To the discussion on secondary succession in tropical forests, we bring data on three under‐addressed issues: understory as well as overstory changes, continuous as opposed to phase changes, and integration of forest succession with indigenous fallow management and plant uses. Changes in vegetation structure and species composition were analyzed in secondary forests following swidden agriculture in a semideciduous forest of Bolivian lowlands. Twenty‐eight fallows, stratified by four successional stages (early = 1–5 yr, intermediate = 6–10 yr, advanced = 12–20 yr, and older = 22–36 yr), and ten stands of mature forests were sampled. The overstory (plants ≥5 cm diameter at breast height [DBH]) was sampled using a 20 × 50 m plot and the understory (plants <5 cm DBH) in three nested 2 × 5 m subplots. Semistructured interviews provided information on fallow management. Canopy height, basal area, and liana density of the overstory increased with secondary forest age. The early stage had the lowest species density and diversity in the overstory, but the highest diversity in the understory. Species composition and abundance differentiated mature forests and early successional stage from other successional stages; however, species showed individualistic responses across the temporal gradient. A total of 123 of 280 species were useful with edible, medicinal, and construction plants being the most abundant for both over‐ and understories. Most of Los Gwarayo preferred mature forests for making new swidden, while fallows were valuable for crops, useful species, and regenerating timber species.