The presence of arbuscular mycorrhizal fungi (AMF) in wetlands is widespread. Wetlands are transition ecosystems between aquatic and terrestrial systems, where shallow water stands or moves over the land surface. The presence of AMF in wetlands suggests that they are ecologically significant; however, their function is not yet clearly understood. With the aim of determining the overall magnitude and direction of AMF effect on wetland plants associated with them in pot assays, we conducted a meta-analysis of data extracted from 48 published studies. The AMF effect on their wetland hosts was estimated through different plant attributes reported in the studies including nutrient acquisition, photosynthetic activity, biomass production, and saline stress reduction. As the common metric, we calculated the standardized unbiased mean difference (Hedges' d) of wetland plant performance attributes in AMF-inoculated plants versus non-AMF-inoculated plants. Also, we examined a series of moderator variables regarding symbiont identity and experimental procedures that could influence the magnitude and direction of an AMF effect. Response patterns indicate that wetland plants significantly benefit from their association with AMF, even under flooded conditions. The beneficial AMF effect differed in magnitude depending on the plant attribute selected to estimate it in the published studies. The nature of these benefits depends on the identity of the host plant, phosphorus addition, and water availability in the soil where both symbionts develop. Our meta-analysis synthetizes the relationship of AMF with wetland plants in pot assays and suggests that AMF may be of comparable importance to wetland plants as to terrestrial plants.

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Soil flooding and salinity can be limiting for arbuscular mycorrhizal fungi (AMF), yet they are found in mangrove ecosystems. Arbuscular mycorrhizal association could influence the functioning of mangrove ecosystems, but little is known about its roll and balance in these dynamic systems.What is the status of the arbuscular mycorrhizal association in C. erectus under natural conditions? Conocarpus erectus is a tree or shrub species that establishes in mangrove ecosystems and is tolerant to elevated levels of salinity and flooding.Three zones representing a range of conditions of salinity were selected in the Ría Lagartos Biosphere Reserve in Mexico, as well as two contrasting collecting seasons in 2009 and 2010: northwind season and drought season.Roots were sampled from C. erectus plants in each zone to evaluate the percentage of arbuscular mycorrhizal colonization and rhizospheric soil samples were taken to evaluate AMF spore density and species richness.The highest percentage of root colonization was recorded in the site of highest salinity during the northwind season, with this value decreasing in the drought season. The same seasonal pattern was observed in spore density. The highest richness was recorded in the site of lowest salinity in both seasons. A total of 16 AMF species were identified.The results suggest that seasonality, in its relation with soil salinity and soil water availability, can influence the development and symbiotic association of the AMF in mangrove associated communities dominated by C. erectus.Arbuscular mycorrhizal fungi, coastal wetland, mangrove, salinity, soil moisture content. ResumenLa inundación y la salinidad del suelo pueden ser limitantes para los hongos micorrízógenos arbusculares (HMA), sin embargo se encuentran en los ecosistemas de manglar. La asociación micorrízica arbuscular (MA) podría influenciar el funcionamiento de los manglares pero se conoce poco su papel en estos sistemas dinámicos.¿Cuál es el estatus de la asociación MA en Conocarpus erectus bajo condiciones naturales? C. erectus, especie arbórea o arbustiva, se establece en los manglares y es tolerante a niveles elevados de salinidad e inundación.Se seleccionaron tres zonas representando un intervalo de condiciones de salinidad en la Reserva de la Biósfera Ría Lagartos en México y dos temporadas contrastantes de muestreo: nortes y sequía.Se colectaron raíces de C. erectus en cada zona para evaluar el porcentaje de colonización MA y se tomaron muestras de suelo rizosférico para evaluar la densidad de esporas y la riqueza de especies de HMA.El porcentaje de colonización radical más elevado fue registrado en el sitio más salino durante la temporada de nortes, disminuyendo en sequía. Se observó el mismo patrón estacional en la densidad de esporas. La mayor riqueza de especies de HMA fue registrada en el sitio menos salino en ambas temporadas. Se identificaron 16 especies de HMA.La estacionalidad, en relación con la salinidad y disponibilidad de agua en el sustrato, puede influenciar el desarrollo e interacción con...