Browsing by Autor "Bette A. Loiselle"

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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
Ecological drivers of avian community assembly along a tropical elevation gradient
(Wiley, 2020) Flavia Montaño‐Centellas; Bette A. Loiselle; Morgan W. Tingley
Community assembly theory hypothesizes that two main niche‐based processes act to shape composition and organization of biological assemblages: abiotic filtering and biological interactions. Here, we conducted repeated surveys of bird abundance along an undisturbed elevational gradient in the tropical Andes to investigate 1) signals of deterministic processes driving community assembly and 2) potential mechanisms by which these forces operate (temperature, habitat complexity, fruit and insect availability), while correcting for imperfect detection and modeling species abundances with N‐mixture models. We observed strong signals of abiotic filtering driving functionally and phylogenetically clustered assemblages towards higher elevations, and a weaker signal of limiting similarity resulting in few overdispersed assemblages at lower elevations. Whereas the decay in species richness with increasing elevation was explained by temperature, trait and phylogenetic dispersion were explained by both temperature and vegetation structure, implying that an interplay of abiotic and biotic mechanisms determines abundance‐based community structure in our montane assemblages. Interestingly, trait and phylogenetic dispersion consistently decreased until ~3000 m but increased above this elevation, highlighting a potential role of competition in resource‐scarce habitats. Combined, our findings suggest abiotic filters are still the main process shaping montane biotas across elevations, whereas resource availability might act locally upon assemblages further modifying them. Our study challenges recent studies in tropical mountains that suggest that biotic filters are a stronger force than abiotic filters in shaping tropical montane assemblages, and exemplifies how accounting for imperfect detection might overcome potential biases in detecting environmental filtering signals in community assembly studies.
Macroinvertebrados bentónicos y metales pesados en el río Pilcomayo (Tarija, Bolivia)
(2005) Claudia Oller; Edgar Goïtia; Bette A. Loiselle; Peter M. Jørgensen
Multiple dimensions of bird beta diversity support that mountains are higher in the tropics
(Wiley, 2021) Flavia Montaño‐Centellas; Bette A. Loiselle; Christy M. McCain
Abstract Aim We examine latitudinal effects of breeding bird taxonomic, phylogenetic and functional β‐diversity (Tβ, Pβ and Fβ, respectively) along elevational gradients to test predictions derived from Janzen's ( The American Naturalist 101 :233–249, 1967) classic ideas that tropical mountains represent stronger dispersal barriers than temperate mountains. Location Global. Taxon Birds. Methods Using a global dataset from 46 mountains, we examine latitudinal patterns of Tβ, Pβ and Fβ, and their components: β rich and β repl . For each mountain and each dimension of diversity, we calculated (a) total β‐diversity, (b) the steepness of distance decay patterns and (c) within‐mountain variability in pairwise β‐diversity and regressed each one of these response variables against absolute latitude. We predicted that tropical montane biotas would have (a) overall higher Tβ, Pβ and Fβ, (b) faster distance decay patterns and (c) higher within‐mountain variability in pairwise β‐diversity. Furthermore, we expected the richness component β rich to be more important in temperate mountains, and the replacement component β repl in tropical mountains. Results Latitude had a negative effect on total β‐diversity for all dimensions of diversity. Similarly, metrics of Tβ and Pβ mostly agree with our expectations, whereas Fβ showed contrasting results with steeper distance decay curves and higher within‐mountain variability in temperate mountains. Overall, β rich was a more important component at high elevations in the tropics and across elevations in temperate mountains, and β repl was more important in tropical low and mid‐elevations. Main Conclusions Our findings are consistent with tropical mountain assemblages containing species with narrow elevational distributions, low dispersal ability and potentially high allopatric speciation, resulting in high β‐diversity across elevations. Contrasting results for Fβ indicate high niche packing in tropical assemblages, with most changes in functional diversity among assemblages involving species redundant in trait space.
Participatory Mapping for Strengthening Environmental Governance on Socio-Ecological Impacts of Infrastructure in the Amazon: Lessons to Improve Tools and Strategies
(Multidisciplinary Digital Publishing Institute, 2021) Carla Mere Roncal; Gabriel Cardoso Carrero; Andrea Chavez; Angélica M. Almeyda Zambrano; Bette A. Loiselle; Felipe Veluk Gutiérrez; Vanessa Luna-Celino; Marliz Arteaga; Eduardo Schmitz Bongiolo; André Segura Tomasi
The Amazon region has been viewed as a source of economic growth based on extractive industry and large-scale infrastructure development endeavors, such as roads, dams, oil and gas pipelines and mining. International and national policies advocating for the development of the Amazon often conflict with the environmental sector tasked with conserving its unique ecosystems and peoples through a sustainable development agenda. New practices of environmental governance can help mitigate adverse socio-economic and ecological effects. For example, forming a “community of practice and learning” (CoP-L) is an approach for improving governance via collaboration and knowledge exchange. The Governance and Infrastructure in the Amazon (GIA) project, in which this study is embedded, has proposed that fostering a CoP-L on tools and strategies to improve infrastructure governance can serve as a mechanism to promote learning and action on factors related to governance effectiveness. A particular tool used by the GIA project for generating and sharing knowledge has been participatory mapping (Pmap). This study analyzes Pmap exercises conducted through workshops in four different Amazonian regions. The goal of Pmap was to capture different perspectives from stakeholders based on their experiences and interests to visualize and reflect on (1) areas of value, (2) areas of concern and (3) recommended actions related to reducing impacts of infrastructure development and improvement of governance processes. We used a mixed-methods approach to explore textual analysis, regional multi-iteration discussion with stakeholders, participatory mapping and integration with ancillary geospatial datasets. We believe that by sharing local-knowledge-driven data and strengthening multi-actor dialogue and collaboration, this novel approach can improve day to day practices of CoP-L members and, therefore, the transparency of infrastructure planning and good governance.