The effects of hurricanes on the stochastic population growth of the endemic epiphytic orchid Broughtonia cubensis living in Cuba

We carried out a posthurricane evaluation of Broughtonia cubensis (Lindl.) Cogn., an endemic Cuban epiphytic orchid, after Hurricane Ivan (2004). We studied the transient responses in the stochastic dynamics of the species at three different sites over 13 successive years (2006–2019), monitored plot inventories (464 individuals in 10 transects) and built stochastic population models. The deterministic stochastic growth rate values (λ) did not significantly differ (F = 2.76; p>0.076) among the three sites over the 2006–2019 period. The long-term stochastic growth rate was λs ¼ 0.973 [0.932, 1.034]. The matrix elements that had the largest effect on λ were the transition to and stasis within the largest size class. Transient responses explained an average of 86% of the variation in the observed population growth rates R2 for rTD vs:robs ð Þ, compared to 4% of the variation in the vital rates R2 for rVR vs:robs ð Þ. Because transient dynamics are dependent on the population size composition, we ran extinction risk analyses under two scenarios: a population composed mainly of juveniles and another composed mainly of adults. There was little risk of falling below the quasi-extinction threshold before 25 year for both juveniles and adults. However, the risk of quasi-extinction was almost certain for both size classes by 80 year. We also simulated the effect of increasing the hurricane occurrence probability over 80 year on the population. There was little risk of extinction before 20 year in the baseline model, but there was a significant risk of extinction within 5 year when 90% of the individuals were affected by a new hurricane event

Spatiotemporal effects of Hurricane Ivan on an endemic epiphytic orchid: 10 years of follow-up

Background: Hurricanes have a strong influence on the ecological dynamics and structure of tropical forests. Orchid populations are especially vulnerable to these perturbations due to their canopy exposure and lack of underground storage organs and seed banks. Aims: We evaluated the effects of Hurricane Ivan on the population of the endemic epiphytic orchid Encyclia bocourtii to propose a management strategy. Methods: Using a pre- and post-hurricane dataset (2003–2013), we assessed the population asymptotic and transient dynamics. We also identified the individual size-stages that maximise population inertia and E. bocourtii’s spatial arrangement relative to phorophytes and other epiphytes. Results: Hurricane Ivan severely affected the survival and growth of individuals of E. bocourtii, and caused an immediate decline of the population growth rate from λ = 1.05 to λ = 0.32, which was buffered by a population reactivity of ρ1 = 1.42. Our stochastic model predicted an annual population decrease of 14%. We found an aggregated spatial pattern between E. bocourtii and its host trees, and a random pattern relative to other epiphytes. Conclusion: Our findings suggest that E. bocourtii is not safe from local extinction. We propose the propagation and reintroduction of reproductive specimens, the relocation of surviving individuals, and the establishment of new plantations of phorophytes.This work was supported by the Inter-ministerial Commission for Science and Technology under Grant [CICYT-Spain, Project CGL2015-69985-R]; and the Havana Project of the University of Alicante

Geopatrimonio del Pedregal del Xitle, Ciudad de México

En ciudades localizadas en campos volcánicos activos, el geopatrimonio cumple una función social muy importante en la construcción de resiliencia ante los peligros naturales. Sin embargo, este tipo de patrimonio es comúnmente desconocido por los citadinos, poco valorizado y por tanto altamente deteriorado o sometido a una fuerte presión urbanística (Vereb et al. 2020). Una manera de conservar este geopatrimonio y hacerlo conocer a sus habitantes es a través de los geositios urbanos que preservan elementos claves de la identidad de una ciudad, son herramientas para educar a un amplio sector de la población sobre los fenómenos naturales, además cumplen con ciertas funciones ecosistémicas y pueden servir de sitios de recreación y de bienestar (Reynard et al. 2017; Vereb et al. 2020; Guilbaud et al. 2021)

Effet de l'irrigation par des eaux usées sur les mycorhizes à arbuscules (apports du fond cosmologique et des amas de galaxies dans le domaine des rayons X)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Mesoamerican Cypripedium: Mycorrhizal Contributions to Promote Their Conservation as Critically Endangered Species

In the valuable orchid genus Cypripedium, the section Irapeana consists of a distinctive group of Mesoamerican species that is formed by Cypripedium dickinsonianum Hágsater, C. irapeanum Lex., and C. molle Lindl. All lady slipper orchids exhibit different distributions and abundances. Data analysis that used herbarium accessions and field investigations indicated that the habitats of these three species have been dramatically reduced. Prospecting for suitable habitats based on climatic, vegetation, and soil parameters allows us to predict potential distributions. Conservation strategies, such as ex situ propagation by asymbiotic and symbiotic approaches, have indicated that the culture media used are a determining factor for seedling development. Mycorrhizal isolates play a main role in the compatibility and further development of germinated seeds. The fungi isolated from adult plants belong to two different families, which makes it possible that widely distributed C. irapeanum populations will be fungal-specific as well as restricted for C. molle. Root mycorrhization patterns occur high on the secondary roots. In contrast with other species of the genus, in situ germination can occur over a short period of two months, but we have documented periods as long as ten years. Cypripedium is a highly problematic genus for ex situ conservation because the germination requirements and cultures are poorly documented, and there is great urgency for in situ conservation to develop strategies for identifying hotspot habitats and actualize the protection status to avoid extinction of this genus

Correlación entre propiedades físico-químicas y biológicas en suelos del distrito de Tlacolula, Oaxaca

Instituto Politécnico Nacional CIIDIR Oaxax

Disease-consensus index as a tool of selecting potential hypoglycemic plants in Chikindzonot, Yucatán, México

There is a general lack of adequate methods to quantitatively assess the importance of specific medicinal plants in a culture. In Mexico like in many other countries type 2 diabetes is an increasing health problem and the use of medicinal plants to treat this disease is widespread. In the present study we propose a mathematical tool for analysing ethnopharmacological field data, with the ultimate aim to select species with most prominent impact on a community to treat a single disease. Using this tool in a Yucatec Mayan community we demonstrate that Malmea depressa (Baill.) R.E. Fr. and Cecropia peltata L. are culturally most salient hypoglycemic plants in this community

Xitle Volcano Geoheritage, Mexico City: Raising Awareness of Natural Hazards and Environmental Sustainability in Active Volcanic Areas

co-auteur étrangerInternational audienceThe conservation of geosites in a region can foster its sustainability and develop geotourism. These geosites provide geoeducation, raise people's awareness on natural hazards and increase their resilience. Low-income cities located in tectonically active areas combine high geohazards with high vulnerability and low sustainability. Geosites in these cities should be a tool to decrease people's vulnerability and foster sustainable development. Mexico City is an ideal case study for its environmental and social issues and its setting in an active 2 continental volcanic arc. The 1,700 yrs-old Xitle volcano, located in the city's SW corner, is a small scoria cone that erupted once, feeding an extensive lava field on which >600,000 people now live. The lavas are very well exposed due to thin soils and extensive quarrying. The Xitle lavas covered the first urban center in the Mexico basin, except for the main pyramid that has become a major archeological site. The cone and lavas have significant geodiversity, sustaining a unique and biodiverse ecosystem. The country's largest university preserves the lavas in an ecological reserve. We describe four exceptional geosites, assess their values, and discuss their relevance for addressing issues such as nature preservation, environmental sustainability, social inequalities, and natural hazards. The Xitle volcano provides a wide range of benefits for the city that are nonetheless unknown to its inhabitants. We describe ongoing initiatives to disseminate such information, such as the Geopedregal site, and propose ways that this heritage could be further protected and used by the city in a sustainable way

Mycorrhizas from the tropical dry forest and other fungal symbioses

Antecedentes y Objetivos: Cada vez se sabe más de la diversidad vegetal en el bosque tropical caducifolio, pero en gran medida se desconocen sus simbiosis micorrízicas. El estatus micorrízico y su morfología aportan información importante sobre su papel ecológico en estos ecosistemas. El objetivo de este trabajo fue describir la morfología y los tipos de asociaciones fúngicas que establecen algunas plantas dominantes del estrato arbóreo del bosque tropical caducifolio en época de secas y lluvias. Métodos: El muestreo de raíces se realizó en la costa del Pacífico de México en Chamela, Jalisco, de 2012 a 2014 y desde Puerto Escondido hasta Salina Cruz, Oaxaca, en 2016. Las raíces se muestrearon a través de núcleos de suelo y por rastreo desde el tronco de Achatocarpus gracilis, Achatocarpus spp., Coccoloba barbadensis, C. liebmannii, Cordia elaeagnoides, Guapira petenensis, Lonchocarpus sp., Ruprechtia fusca y R. aff. pallida. Se revisó cada raíz en el microscopio estereoscópico en busca de micorrizas; algunas se aclararon, tiñeron y se montaron en laminillas; se hicieron cortes anatómicos, se tomaron fotografías con microscopio óptico y se describieron las asociaciones rizosféricas según los referentes morfológicos para cada tipo de micorriza. Resultados clave: Todas las plantas tuvieron asociaciones micorrízicas activas en época de secas y de lluvias. Se describieron 64 morfotipos ectomicorrízicos que presentaron variantes morfológicas: zonación del manto en raicillas secundarias o formación de manto incipiente; ausencia de ramificación; ausencia de la red de Hartig o presencia con estructuras intracelulares. Achatocarpus presentó micorrizas duales de ectomicorrizas con micorrizas arbusculares. Conclusiones: Nuestros resultados coinciden en las diferencias morfológicas en las ectomicorrizas que fueron observadas previamente para Nyctaginaceae en Ecuador y Brasil, y se amplían estas observaciones a más familias dentro de Caryophyllales y la familia Fabaceae. Con estas observaciones, y lo reportado previamente, se propone un nuevo concepto morfológico de ectomicorriza “incipiente” para angiospermas tropicales.Background and Aims: The knowledge on plant diversity in the tropical dry forest is constantly increasing, but the knowledge of its mycorrhizal symbioses is scarce. The mycorrhizal status and its morphology provide important information on its ecological role in these ecosystems. The aim of this study was to describe the morphology and fungal association types that some dominant arboreal stratum plants establish in the tropical deciduous forest in both dry and rainy seasons. Methods: Root sampling was performed along the Mexico Pacific coast in Chamela, Jalisco, from 2012 to 2014, and from Puerto Escondido to Salina Cruz, Oaxaca, in 2016. Root samples were collected with soil cores and tracking them from the trunk of Achatocarpus gracilis, Achatocarpus spp., Coccoloba barbadensis, C. liebmannii, Cordia elaeagnoides, Guapira petenensis, Lonchocarpus sp., Ruprechtia fusca, and R. aff. pallida. Each root was reviewed under the stereomicroscope for mycorrhizae; some roots were clarified, stained and mounted on slides; anatomical sections were made, photographs were taken with an optical microscope and the rhizospheric associations were described according to the morphological referents for each type of mycorrhiza. Key results: All plants had active mycorrhizal associations in dry and rainy seasons. Sixty-four ectomycorrhizal morphotypes were described presenting the following morphological variants: zonation of the mantle in secondary roots or incipient mantle formation; absence of branching; absence of Hartig net or presence with intracellular structures. Achatocarpus presented dual mycorrhizae of ectomycorrhizae with arbuscular mycorrhizae. Conclusions: Our results coincide on the ectomycorrhizal morphological differences previously observed in Nyctaginaceae in Ecuador and Brazil, and we extend these observations to more families within Caryophyllales and the family Fabaceae. Our observations, together with previous reports, make us propose a new morphological concept of "incipient" ectomycorrhiza for tropical angiosperms