Ecological filters shape arbuscular mycorrhizal fungal communities in the rhizosphere of secondary vegetation species in a temperate forest

Abstract

The community assembly of arbuscular mycorrhizal fungi (AMF) in the rhizosphere results from the recruitment and selection of different AMF species with different functional traits. The aim of this study was to analyze the relationship between biotic and abiotic factors and the AMF community assembly in the rhizosphere of four secondary vegetation (SV) plant species in a temperate forest. We selected four sites at two altitudes, and we marked five individuals per plant species at each site. Soil rhizosphere samples were collected from each SV plant species, during the rainy and dry seasons. Soil samples from the rhizosphere of each plant species were analyzed for AMF spores, organic matter (OM), pH, soil moisture, and available phosphorus, and nitrogen. Three ecological filters influenced the AMF community assembly: host plant identity, abiotic factors, and AMF species co-occurrence. This assembly consisted of 61 AMF species, with different β-diversity values among plant species across seasons and altitudes. Canonical correspondence analysis revealed that AMF community composition is linked to OM and available P and N, with only a few AMF species co-occurring, while most do not. Our study highlights how ecological filters shape AMF structure, which is essential for understanding how soil and environmental factors affect AMF in SV plant species across seasons and altitudes.

Fig 1. Geographic location of the sampling sites.

Abies religiosa forest of the Magdalena river basin, Mexico City, Mexico. Site 1 = 2150 m², Site 2 = 2070 m², Site 3 = 2731 m², Site 4 = 2709m².

Fig 2. Study plant species with their reproductive structures.

A) Acaena elongata, B) Ageratina glabrata, C) Solanum pubigerum and D) Symphoricarpos microphyllus, all located in the Abies religiosa forest of the Magdalena river basin, Mexico City, Mexico.

Fig 3. Network of interactions between the host plant species and the arbuscular mycorrhizal fungi in both seasons and at different altitudes in an A. religiosa forest of the Magdalena river basin, Mexico City.

Rainy season and dry season (a and b), high altitude and low altitude (c and d).The lines represent connections, and their thickness indicates the intensity of these connections. The size of the nodes is related to the number and intensity of the connections.

Fig 4. Co-occurrence Matrix Species for all possible pairwise comparisons among arbuscular mycorrhizal fungi (AMF) species.

Map showing the positive and negative species associations determined by the probabilistic co-occurrence model for secondary vegetation four plant species in the Abies religiosa forest of the Magdalena river basin, Mexico City, Mexico. AMF species names are positioned to indicate the columns and rows that represent their pairwise relationships with other species.

Fig 5. Arbuscular mycorrhizal fungi (AMF) beta diversity.

Non-metric multidimensional scaling showing the dissimilarity in AMF species composition of sampled individuals (dots) of each host plant species in the wet and dry seasons and their location at high and low altitudes in the Abies religiosa forest of the Magdalena River basin, Mexico City, Mexico. A) Acaena elongata, B) Ageratina glabrata, C) Solanum pubigerum and D) Symphoricarpos microphyllus. The different symbol shapes are related to the host plant species and altitude, and the different colors indicate the season (bluish-green for the rainy and orange for the dry one).

Fig 6. Relationship between biotic and abiotic factors.

Canonical Correspondence Analysis (CCA) showing the relationship between arbuscular mycorrhizal fungi (AMF) community composition associated to rhizosphere soil of four host plant species and the abiotic factors (red arrows) in the Abies religiosa forest of the Magdalena river basin, Mexico City, Mexico. N = total nitrogen, pH = soil pH, MO = soil organic matter, CE = soil electrical conductivity, K = soil potassium. P = soil available phosphorus. NH₄⁺ = ammonium, NO₃^- = nitrate, RSM = relative soil moisture. Blue dots correspond to the rainy season, orange dots to the dry season. High = higher altitude and low = lower altitude. The different shapes are related to the plant species and the different colors are related to the season (blue = rainy and orange = dry). Where the species name is composed as follows: Plant genus_altitude (High = altitude and Low = altitude).