Phylogenetic relatedness as a tool in restoration ecology: a meta-analysis

7 pages, 1 figure, 2 tables, 52 references.Biotic interactions assembling plant communities can be positive (facilitation) or negative (competition) and operate simultaneously. Facilitative interactions and posterior competition are among the mechanisms triggering succession, thus representing a good scenario for ecological restoration. As distantly related species tend to have different phenotypes, and therefore different ecological requirements, they can coexist, maximizing facilitation and minimizing competition. We suggest including phylogenetic relatedness together with phenotypic information as a predictor for the net effects of the balance between facilitation and competition in nurse-based restoration experiments. We quantify, by means of a Bayesian meta-analysis of nurse-based restoration experiments performed worldwide, the importance of phylogenetic relatedness and life-form disparity in the survival, growth and density of facilitated plants. We find that the more similar the life forms of neighbouring plants are the greater the positive effect of phylogenetic distance is on survival and density. This result suggests that other characteristics beyond life form are also contained in the phylogeny, and the larger the phylogenetic distance, the less is the niche overlap, and therefore the less is the competition. As a general rule, we can maximize the success of the nurse-based practices by increasing life-form disparity and phylogenetic distances between the neighbour and the facilitated plant.This work was funded by AECID (Projects A017475/08, A023461/09), DGAPA-UNAM (Project IN-224808-3) and CYTED (Acción 409AC0369).Peer reviewe

Tectono-stratigraphic basin evolution in the Tehuacán-Mixteca highlands, south western México

The morphological evolution of the basins in the Sierra Madre del Sur (SMS), southern México is poorly understood. This work explains for the first time the geomorphological development of the tectonic, fluvially-interconnected SMS basins named San Juan Raya (SJRb) and Zapotitlán (ZAPb). The evolution of the SJRb and ZAPb are analysed within the context of the transformations of the well-studied Tehuacán basin (TEHb). A new interpretation of a series of tectonic features of the TEHb valley area is also presented. Published geological data and extensive field work provided the basis for our geomorphological and evolutionary interpretation of basin evolution of this part of Mesoamerica during the late Cenozoic. Stratigraphic and sedimentary records suggest that after the late Cretaceous-early Cenozoic orogeny the TEHb and ZAPb were closed basins, and that the TEHb graben system was activated during the Paleogene as a response to the dominant regional NW-SE trending faults. We propose that the ZAPb and SJRb formed sequentially during the Neogene as a result of new E-W, N-S and NE-SW faults. The continuation of the TEHb extension during the Oligocene widened its lowland area and allowed the formation of an extensive lake. No alluvial or fluvial records of this interval are found in the ZAPb and SJRb. No sedimentation rather than formation and subsequent erosion of such sediments is supported by the basin morphology and by the absence of re-worked alluvial deposits at the outlet area where both connect to the TEHb. By middle to late Miocene the TEHb lost its endorheic configuration, ending the lake-type deposition while new faults initiated the opening of the ZAPb. Intensive tectonics, alluvial deposition and the confinement of the Tehuacán lake to the north sector of this basin characterised the Pliocene. During the late Pliocene to the early Pleistocene the formation of the SJRb was initiated. Quaternary faulting related to basin extension along the north watershed of the SJRb and ZAPb is supported by independent data on the biogeography of the cactus Mammillaria pectinifera. We introduce the idea that the departure from the regional NW-SE fault alignment that formed the major Miocene basins to a more local E-W trend that formed Neogene-Quaternary basins was probably a response to the latest post-orogenic relaxation of the crust in the Mixteca terrane

Beyond species loss: The extinction of ecological interactions in a changing world

© 2014 The Authors. The effects of the present biodiversity crisis have been largely focused on the loss of species. However, a missed component of biodiversity loss that often accompanies or even precedes species disappearance is the extinction of ecological interactions. Here, we propose a novel model that (i) relates the diversity of both species and interactions along a gradient of environmental deterioration and (ii) explores how the rate of loss of ecological functions, and consequently of ecosystem services, can be accelerated or restrained depending on how the rate of species loss covaries with the rate of interactions loss. We find that the loss of species and interactions are decoupled, such that ecological interactions are often lost at a higher rate. This implies that the loss of ecological interactions may occur well before species disappearance, affecting species functionality and ecosystems services at a faster rate than species extinctions. We provide a number of empirical case studies illustrating these points. Our approach emphasizes the importance of focusing on species interactions as the major biodiversity component from which the 'health' of ecosystems depends.Peer Reviewe

Human impacts on multiple ecological networks act synergistically to drive ecosystem collapse

Highly biodiverse ecosystems worldwide are rapidly losing species diversity as a result of human overexploitation of natural resources. However, it is not known whether there is a critical threshold of species loss at which an ecosystem fails to recover, leading to its collapse. By combining multiple ecological networks (including facilitation, pollination, and seed dispersal) into a realistic scenario, we document how an ecosystem may collapse through synergistic disruptions to those networks. Although the interdependence of different ecological networks is indicative of ecosystem fragility and low resilience, our findings may improve environmental remediation efforts, thereby helping to bridge the gap between the disciplines of ecology and conservation biology. © The Ecological Society of America.Funding was provided by PAPIIT-DGAPA, UNAM (IN-202811-3) and CYTED (Acción 409AC0369). AV-B and MV conceived the study, analyzed the data, and wrote the manuscript.Peer Reviewe

The nested assembly of plant facilitation networks prevents species extinctions

11 páginas, 3 figuras, 4 tablas.Facilitation is a positive interaction assembling ecological communities and preserving global biodiversity. Although communities acquire emerging properties when many species interact, most of our knowledge about facilitation is based on studies between pairs of species. To understand how plant facilitation preserves biodiversity in complex ecological communities, we propose to move from the study of pairwise interactions to the network approach. We show that facilitation networks behave as mutualistic networks do, characterized by a nonrandom, nested structure of plant-plant interactions in which a few generalist nurses facilitate a large number of species while the rest of the nurses facilitate only a subset of them. Consequently, generalist nurses shape a dense and highly connected network. Interestingly, such generalist nurses are the most abundant species in the community, making facilitation-shaped communities strongly resistant to extinction, as revealed by coextinction simulations. The nested structure of facilitative networks explains why facilitation, by preventing extinction, preserves biodiversity.D. Ackerly, J. Bascompte, M. C. Castellanos, J. P. Castillo, R. Cruz, P. García-Fayos, and P. Jordano provided valuable comments on the manuscript. J. P. Castillo, M. Morales, C. Rodríguez, C. Silva-Pereyra, C. Soberanes, and A. Vital helped with field samplings. Our research is funded by the Dirección General de Asuntos del Personal Académico–Universidad Nacional Autónoma de México projects IN-227605 and IN-224808 and by Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo, Subprograma Diversidad Biológica (project XII-6), for travel expenses to A.V.-B.Peer reviewe

Vulnerabilidad de los sistemas de polinización de cactáceas columnares de México Vulnerability of pollination systems of columnar cacti of Mexico

Se presenta un análisis geográfico sobre el grado de vulnerabilidad de los sistemas de polinización de cactáceas columnares de México que muestran un síndrome de polinización quiropterófila. Se partió del supuesto que sistemas especializados de polinización serían más vulnerables a la perturbación humana que los generalistas. Los resultados indican que las especies que se ubican en el límite norte de la distribución de las cactáceas columnares muestran patrones generalistas de polinización que las hace menos vulnerables a las perturbaciones que las que habitan el centro de México que presentan sistemas de interacción especializados. Este patrón contrastante podría estar relacionado con los movimientos migratorios de los murciélagos en el norte de la distribución de las cactáceas que pudo haber restringido la respuesta hacia la especialización, en tanto que poblaciones residentes de murciélagos en el centro de México podrían haber favorecido la especialización local<br>An analysis of the degree of vulnerability of the pollination systems of Mexican columnar cacti showing a chiropterophyllous pollination syndrome was conducted, assuming that specialized pollination interactions would be more vulnerable to human perturbations. The results indicate that the species inhabiting the northern distribution limit of the columnar cacti show generalized pollination systems whereas species inhabiting central Mexico showing specialized pollination interactions would be more vulnerable to perturbations. This contrasting geographic pattern might be related to the migratory movements of the nectar-feeding bats in the northern limit of distribution of the columnar cacti that restricted local specialization, whereas resident nectar-feeding bat populations in south-central Mexico probably favored local specializatio

Trait divergence and indirect interactions allow facilitation of congeneric species

8 páginas, 1 figura.Background. Plant facilitation occurs when the presence of a plant (i.e. a nurse plant) modifies the environment, making it more favourable for the establishment and survival of other species (i.e. facilitated plants), which can germinate and grow nearby. Facilitative associations can be maintained or turned into competition as the facilitated seedling grows. According to the competition-relatedness hypothesis that suggests that closely related species tend to compete more, facilitation turns into competition between phylogenetically close species. However, some examples of facilitation between congeneric species, which are supposed to be closely related species, have been found in nature.Scope. In this work, some examples of congeneric facilitation and subsequent coexistence are reviewed and an attempt is made to explain those exceptions to the competition-relatedness hypothesis.Conclusions. Two mechanisms are proposed that can switch the facilitation–competition balance: trait divergence and indirect interactions. When traits have diverged within the genus, the niche overlap is reduced and competition relaxed, thus allowing the coexistence of congeneric species. The presence of third interplayers (mycorrhizal fungi, seed dispersers, pollinators or pathogens) participating in the interaction between plants can alleviate the competition or enhance the reproduction and allow the coexistence of species that could not coexist in their absence.We thank Alicia Montesinos for her helpful comments on the manuscript. This work was funded by AECID (Projects A017475/08, A023461/09), MICINN (CGL2011-29585-C02- 01), DGAPA-UNAM (Projects IN-224808-3 and IN-202811-3) and CYTED (Acción 409AC0369).Peer reviewe