Browsing by Autor "Francisco Saavedra"

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Bracken fern facilitates tree seedling recruitment in tropical fire-degraded habitats
(Elsevier BV, 2014) Silvia C. Gallegos; Isabell Hensen; Francisco Saavedra; Matthias Schleuning
Deforested habitats lack seeds of late‐successional and large‐seeded plant species in tropical montane forests
(Wiley, 2015) Francisco Saavedra; Isabell Hensen; Matthias Schleuning
Abstract Questions (1) How do seed density and species richness of late‐successional, pioneer and non‐forest species change from forest interior to deforested habitats? (2) Are seed density and species richness of seed species dispersed into deforested areas enhanced by perch structures? (3) Do morphological seed traits of forest and non‐forest plant species change from the forest interior to deforested areas? Location Deforested tropical mountains of Chulumani, La Paz, Bolivia. Methods At eight study sites, we installed a system of 38 seed traps along a transect of 240 m from the forest interior (160 m from the forest margin) toward deforested areas (80 m from the forest margin). Half of the seed traps installed in the deforested areas were positioned under perch structures. We identified captured seeds to morpho‐species or species level and recorded morphological seed traits (i.e. seed mass, seed length, seed width) and species origin (i.e. late‐successional, pioneer, non‐forest species). Results Seed density and species richness of late‐successional and pioneer species declined from the forest interior toward deforested areas. Seed limitation was particularly strong for large‐seeded species. Perches in deforested areas strongly increased the density and to some extent as well as the species richness of seeds dispersed into these areas, but did not alter the composition of seed traits and species origin in comparison to seed traps without perches. Conclusions We found a strong seed dispersal limitation in deforested areas, which was mitigated by the presence of perch structures, at least in terms of seed density and species richness. However, the dispersal limitation of late‐successional plant species with large seeds was not compensated by the presence of perching structures. Nevertheless, the establishment of artificial perch structures is likely to be a promising strategy for capturing seeds in deforested areas that may establish under bracken fronds in the long term.
Depredación post-dispersión de "Guettarda viburnoides" (Rubiaceae) en sabanas neotropicales del noreste de Bolivia: su efecto a pequeña escala espacial
(2012) Francisco Saavedra; Andrea P. Loayza; Mónica Moraes R.
Effects of environmental variables and foliar traits on the transpiration rate of cocoa (Theobroma cacao L.) under different cultivation systems
(Springer Science+Business Media, 2020) Francisco Saavedra; Ernesto Jordan Peña; Monika Schneider; Kazuya Naoki
Factors limiting montane forest regeneration in bracken-dominated habitats in the tropics
(Elsevier BV, 2016) Silvia C. Gallegos; Stephan Beck; Isabell Hensen; Francisco Saavedra; Denis Lippok; Matthias Schleuning
Forest recovery of areas deforested by fire increases with elevation in the tropical Andes
(Elsevier BV, 2013) Denis Lippok; Stephan Beck; Daniel Renison; Silvia C. Gallegos; Francisco Saavedra; Isabell Hensen; Matthias Schleuning
Functional importance of avian seed dispersers changes in response to human-induced forest edges in tropical seed-dispersal networks
(Springer Science+Business Media, 2014) Francisco Saavedra; Isabell Hensen; Stephan Beck; Katrin Böhning‐Gaese; Denis Lippok; Till Töpfer; Matthias Schleuning
Seed-deposition and recruitment patterns of Clusia species in a disturbed tropical montane forest in Bolivia
(Elsevier BV, 2017) Francisco Saavedra; Isabell Hensen; Amira Apaza‐Quevedo; Eike Lena Neuschulz; Matthias Schleuning
Similar composition of functional roles in Andean seed‐dispersal networks, despite high species and interaction turnover
(Wiley, 2020) D. Matthias Dehling; Guadalupe Peralta; Irene M. A. Bender; Pedro G. Blendinger; Katrin Böhning‐Gaese; Marcia C. Muñoz; Eike Lena Neuschulz; Marta Quitián; Francisco Saavedra; Vinicio Santillán
The species composition of local communities varies in space, and its similarity generally decreases with increasing geographic distance between communities, a phenomenon known as distance decay of similarity. It is, however, not known how changes in local species composition affect ecological processes, that is, whether they lead to differences in the local composition of species' functional roles. We studied eight seed-dispersal networks along the South American Andes and compared them with regard to their species composition and their composition of functional roles. We tested (1) if changes in bird species composition lead to changes in the composition of bird functional roles, and (2) if the similarity in species composition and functional-role composition decreased with increasing geographic distance between the networks. We also used cluster analysis to (3) identify bird species with similar roles across all networks based on the similarity in the plants they consume, (i) considering only the species identity of the plants and (ii) considering the functional traits of the plants. Despite strong changes in species composition, the networks along the Andes showed similar composition of functional roles. (1) Changes in species composition generally did not lead to changes in the composition of functional roles. (2) Similarity in species composition, but not functional-role composition, decreased with increasing geographic distance between the networks. (3) The cluster analysis considering the functional traits of plants identified bird species with similar functional roles across all networks. The similarity in functional roles despite the high species turnover suggests that the ecological process of seed dispersal is organized similarly along the Andes, with similar functional roles fulfilled locally by different sets of species. The high species turnover, relative to functional turnover, also indicates that a large number of bird species are needed to maintain the seed-dispersal process along the Andes.
Specialists and generalists fulfil important and complementary functional roles in ecological processes
(Wiley, 2021) D. Matthias Dehling; Irene M. A. Bender; Pedro G. Blendinger; Katrin Böhning‐Gaese; Marcia C. Muñoz; Eike Lena Neuschulz; Marta Quitián; Francisco Saavedra; Vinicio Santillán; Matthias Schleuning
Abstract Species differ in their resource use and their interactions with other species and, consequently, they fulfil different functional roles in ecological processes. Species with specialized functional roles (specialists) are considered important for communities because they often interact with species with which few other species interact, thereby contributing complementary functional roles to ecological processes. However, the contribution of specialists could be low if they only interact with a small range of interaction partners. In contrast, species with unspecialized functional roles (generalists) often do not fulfil complementary roles but their contribution to ecological processes could be high because they interact with a large range of species. To investigate the importance of the functional roles of specialists versus generalists, we tested the relationship between species' degree of specialization and their contribution to functional‐role diversity for frugivorous birds in Andean seed‐dispersal networks. We used two measures for the specialization of birds—one based on the size, and one based on the position of their interaction niche—and measured their effect on the birds' contribution to functional‐role diversity and their functional complementarity, a measure of how much a species' functional role is complementary to those of the other species. In all networks, there were similar log‐normal distributions of species' contributions to functional‐role diversity and functional complementarity. Contribution to functional‐role diversity and functional complementarity increased with both increasing niche‐position specialization and increasing niche size, indicating that the composition of functional roles in the networks was determined by an interplay between specialization and generalization. There was a negative interaction between niche‐position specialization and niche size in both models, which showed that the positive effect of niche‐position specialization on functional‐role diversity and functional complementarity was stronger for species with a small niche size, and vice versa. Our results show that there is a continuum from specialized to generalized functional roles in species communities, and that both specialists and generalists fulfil important functional roles in ecological processes. Combining interaction networks with functional traits, as exemplified in this study, provides insight into the importance of an interplay of redundancy and complementarity in species' functional roles for ecosystem functioning. A free Plain‐Language Summary can be found within the Supporting Information of this article.