Species composition of arbuscular mycorrhizal fungi differ in semi-natural and intensively managed pastures in an isolated oceanic island (Terceira, Azores)

Abstract

Nothing is published about the arbuscular mycorrhizal fungi (AMF) of the Azores archipelago, either with regard to individual species, or at the community level. This study, based on identification through spore morphological characteristics, compares the AMF community structure of semi-natural and intensively managed pastures. Thirty-nine glomeromycotan fungal spore types were detected in soil, with species in the genera Acaulospora, Ambispora, Archaeospora, Claroideoglomus, Entrophospora, Gigaspora, Paraglomus, Sclerocystis, Scutellospora sensu Morton and Msiska (Mycorrhiza 20 483-496, 2010) and Rhizophagus. The two most representative groupings were the glomoid spore types and Acaulospora with 13 and 10 species respectively, followed by Scutellospora with 3. The glomeromycotan fungal richness was similar for both intensive and semi-natural pastures, with 28 spore types in the former and 23 in the latter but their composition differed. Semi-natural pastures were dominated by species from Acaulospora and Scutellospora, particularly S. calospora and A. cf. myriocarpa, while for intensively farmed pastures, species with glomoid spores, and members of the two genera Claroideoglomus and Paraglomus were found most frequently and abundantly. Spore densities of the most commonly found groupings -Acaulospora, Claroideoglomus, Scutellospora and the glomoid spores were correlated with soil chemical properties, suggesting that soil characteristics influence the AMF communities. These results indicate that intensity of pasture management may not influence AMF richness but is probably an important factor influencing their composition and abundance.

Distribution of arbuscular mycorrhizal fungi (AMF) in Terceira and São Miguel Islands (Azores)

“…Consequently, it is necessary to establish trap cultures to promote sporulation and provide specimens for detailed examination. Open pot-trap cultures (Gilmore 1968) were established from each soil sample collected at semi-natural and intensive pastures with one-week-old Zea mays seedlings (Melo et al 2014). Soil samples collected from the native forests were used to establish two of such cultures, one with one-week-old Z. mays seedlings and another one with micropropagated J. brevifolia and P. azorica seedlings (Melo et al 2017).…”

“…Study area description: All data used in this study came from surveys about AMF diversity and composition in different ecosystems (pasturelands and native forests) conducted in two Islands of the Azorean archipelago, Terceira and São Miguel (Melo et al 2014, Melo et al 2017 (Fig. 1).…”

“…2). The two pasture types include semi-natural pastures with low grazing intensity and frequency (managed for more than 50 years, with low stocking density, grazed only in summer and with a relatively high diversity of grasses and forbs) and intensively-managed pastures with high grazing intensity and frequency (managed for more than 30 years, with high stocking density, grazing during all year and characterised also by a depauperate vascular flora of five or fewer dominant species) (Melo et al 2014). The semi-natural pastures, Pico Galhardo (TER_SP_PG) and Terra Brava (TER_SP_TB) ( Fig.…”

“…1) are included in Terceira Natural Park and are dominated by the perennial grasses Holcus lanatus and Agrostis castellana, have a high floristic diversity (Dias 1996, Borges 1997, often including other grasses such as Anthoxanthum odoratum, Lolium multiflorum, Holcus rigidus and Poa trivialis and non-forage species including Lotus uliginosus, Rumex acetosella ssp. angiocarpus, Potentilla anglica, Hydrocotyle vulgaris, Plantago lanceolata and Lobelia urens (For more details see Melo et al 2014). The intensively-managed pastures, Agualva 1 (TER_IP_R1) and Agualva 2 (TER_IP_R2) (Fig.…”

A new family, Pervetustaceae with a new genus, Pervetustus, and P. simplex sp. nov. (Paraglomerales), and a new genus, Innospora with I. majewskii comb. nov. (Paraglomeraceae) in the Glomeromycotina

“…Esto parece razonable ya que Claroideoglomus, se ha encontrado con frecuencia como dominante entre algunas zonas y las dos leguminosas forrajeras de este estudio (Tablas 11 y 12). Lo que concuerda con Melo et al, (2014), quienes reportaron que, en pastos intensivos, el género Claroideoglomus se encontró con mayor frecuencia y abundancia, además mencionan que las densidades de esporas de las agrupaciones más comúnmente encontradas de Claroideoglomus, se correlacionaron con las propiedades químicas del suelo, lo que sugiere que las características del suelo influyen en las comunidades de HMA, y que la intensidad del manejo de los pastos puede no influir en la riqueza de HMA, pero es probable que sea un factor importante que influya en su composición y abundancia.…”