Browsing by Autor "Fernando Casanoves"

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CacaoFIT: the network of cacao field trials in Latin America and its contribution to sustainable cacao farming in the region
(Frontiers Media, 2024) Luis Orozco-Aguilar; Arlene López-Sampson; Rolando Cerda; Fernando Casanoves; Oscar Ramírez-Argueta; Javier Diaz Matute; Juan Carlos Suárez; Johanna Rüegg; Stéphane Saj; Joaquin Milz
A network of agronomists, researchers, and practitioners associated with cacao farming provided open access to their independent field trials across Latin America and the Caribbean (LAC). A centralized dataset was assembled using qualitative and quantitative data from 25 experimental field trials (hereafter referred to as “CacaoFIT”) spanning several LAC agroecosystems. This dataset was used to document the main traits and agroclimatic attributes of the cacao cultivation model being tested within the CacaoFIT network. By synthesizing data from an entire network of cacao trials, this study aimed to highlight specific design features and management practices that may contribute to better cacao farming sustainability. The CacaoFIT network comprises 200 ha of field trials testing over 150 cacao genotypes and set up under different shade canopy design, management, and research goals. Small-sized trials were common across Mesoamerica, whereas medium to large-size trials were distinct to South America. Cacao trials were 15 years old (on average) and ranged from 3 to 25 years of establishment. Most cacao trials were managed conventionally (i.e., 55%), while 20% were under organic practices, and the remaining 25% presented both conventional and organic management approaches. Most field trials (ca. 60%) planted an average of 10 international clones or national cultivars at high (1,230–1,500 plants ha −1 ) and medium density (833–1,111 plants ha −1 ). Mixed shade canopies were the dominant agroforestry model, while timber vs. leguminous shade canopies were also common. The diversity and depth of research domains examined across the CacaoFIT network varied widely. Agronomy and agroforestry topics dominated the research agenda across all trials, followed by environmental services domains. Cacao physiology and financial performance were researched to a lesser extent within the network. Five featured field trials from CacaoFIT offered technical guidelines to inform cacao farming within similar contexts. This collaborative work is a scaffold to encourage public–private partnerships, capacity building, and data sharing amongst cacao researchers across the tropics.
Does functional trait diversity predict above‐ground biomass and productivity of tropical forests? Testing three alternative hypotheses
(Wiley, 2014) Bryan Finegan; Marielos Peña‐Claros; Alexandre A. Oliveira; Nataly Ascarrunz; M. Syndonia Bret‐Harte; Geovana Carreño‐Rocabado; Fernando Casanoves; Sandra Dı́az; Paúl Eguiguren; Fernando Fernández‐Méndez
Summary Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. Data are presented for three rain forests in Bolivia, Brazil and Costa Rica. Initial above‐ground biomass and biomass increments of survivors, recruits and survivors + recruits (total) were estimated for trees ≥10 cm d.b.h. in 62 and 21 1.0‐ha plots, respectively. We determined relationships of biomass increments to initial standing biomass ( AGB i ), biomass‐weighted community mean values ( CWM ) of eight functional traits and four functional trait variety indices (functional richness, functional evenness, functional diversity and functional dispersion). The forest continuum sampled ranged from ‘slow’ stands dominated by trees with tough tissues and high AGB i , to ‘fast’ stands dominated by trees with soft, nutrient‐rich leaves, lighter woods and lower AGB i . We tested whether AGB i and biomass increments were related to the CWM trait values of the dominant species in the system (the biomass ratio hypothesis), to the variety of functional trait values (the niche complementarity hypothesis), or in the case of biomass increments, simply to initial standing biomass (the green soup hypothesis). CWM s were reasonable bivariate predictors of AGB i and biomass increments, with CWM specific leaf area SLA , CWM leaf nitrogen content, CWM force to tear the leaf, CWM maximum adult height H max and CWM wood specific gravity the most important. AGB i was also a reasonable predictor of the three measures of biomass increment. In best‐fit multiple regression models, CWM H max was the most important predictor of initial standing biomass AGB i . Only leaf traits were selected in the best models for biomass increment; CWM SLA was the most important predictor, with the expected positive relationship. There were no relationships of functional variety indices to biomass increments, and AGB i was the only predictor for biomass increments from recruits. Synthesis . We found no support for the niche complementarity hypothesis and support for the green soup hypothesis only for biomass increments of recruits. We have strong support for the biomass ratio hypothesis. CWM H max is a strong driver of ecosystem biomass and carbon storage and CWM SLA , and other CWM leaf traits are especially important for biomass increments and carbon sequestration.
Species interactions across trophic levels mediate rainfall effects on dryland vegetation dynamics
(Wiley, 2020) Ariel A. Farías; Cristina Armas; Aurora Gaxiola; Patricia Agudelo‐Romero; Jose Luis Cortés; Ramiro Pablo López; Fernando Casanoves; Milena Holmgren; Peter L. Meserve; Julio R. Gutiérrez
Abstract Arid ecosystems are strongly limited by water availability, and precipitation plays a major role in the dynamics of all species in arid regions, as well as the ecosystem processes that occur there. However, understanding how biotic interactions mediate long‐term responses of dryland ecosystems to rainfall remains very fragmented. We report on a unique large‐scale field experiment spanning 25 yr and three trophic levels (plants, small mammal herbivores, predators) in a dryland ecosystem in the northern Chilean Mediterranean Region where we assessed how biotic interactions influence the long‐term plant community responses to precipitation. As the most persistent ecological changes in dryland systems may result from changes in the structure, cover, and composition of the perennial vegetation, we emphasized the interplay between bottom‐up and top‐down controls of perennial plants in our analyses. Rainfall was the primary factor affecting the dynamics of, and interactions among, plants and small mammals. Ephemeral plant cover dynamics closely tracked short‐term annual rainfall, but seemed unaffected by top‐down controls (herbivory). In contrast, the response of the perennial plant cover to precipitation was mediated by (1) a complex interplay between subtle top‐down (herbivory) controls that become more apparent in the long‐term, (2) competition with ephemeral plants during wet years, and (3) an indirect effect of predators on subdominant shrubs and perennial herbs. This long‐term field experiment highlights how climate‐induced responses of arid perennial vegetation are influenced by interactions across trophic levels and temporal scales. In the face of global change, understanding how multi‐trophic controls mediate dryland vegetation responses to climate is essential to properly managing the conservation of biodiversity in arid systems.