Comparison of diversity and composition of macrofungal species between intensive mushroom harvesting and non-harvesting areas in Oaxaca, Mexico

Abstract

Wild edible mushrooms have been collected and consumed by human groups for centuries, and today they represent a relevant source of food and income for many rural families worldwide. Preserving these non-timber forest products is of great interest, and there is concern about the damage caused by intensive mushroom harvesting on macromycete communities. The aim of this study was to evaluate variation in diversity and composition of macromycete species between areas regularly used for mushroom harvesting and non-harvested areas in the Mixteca region of Oaxaca, Mexico, as well as to assess the influence of microclimatic and environmental factors on this variation. We selected two harvested and two non-harvested sites within the study area. In each one, we established 10 permanent plots of 10 m × 10 m where we sampled all the observed fruit bodies weekly from June to October 2017. We recorded a total of 856 individuals corresponding to 138 species, and 23 of these were identified as edible. Overall macromycete diversity, edible species diversity and composition were similar in Sites 1 (non-harvested) and 3 (harvested), and in Sites 2 (non-harvested) and 4 (harvested). Variation of diversity and species composition along the studied area was mainly related to microclimatic variables, while most environmental variables and variables related to vegetation structure similarly affected macromycete species in the four sites. Our results indicate that intensive harvesting of wild edible mushrooms is not affecting the diversity and distribution of macromycete species in our study area. Knowledge on the sustainability of mushroom harvesting practices can help improve current regulations regarding the management of these valuable non-timber forest products.

Keywords: Distribution; Diversity; Edible mushrooms; Management; Non-timber forest product; Pine-oak forest.

Figure 1. (A) Rarefaction and (B) accumulation curves for species richness in the four studied sites based on a standardized number of individuals and plots as sampling effort, respectively.

Vertical lines in rarefaction curves indicates species richness for the minimum number of individuals recorded in a study site.

Figure 2. Monthly variation of (A) soil water content, (B) air temperature, (C) air relative humidity, and (D) soil temperature in the studied sites through the sampling season.

Figure 3. Cluster analysis for the four studied sites, based on composition of species and abundance.

Euclidian distance is indicated by height values.

Figure 4. CCA for all the recorded macromycetes in the four study sites.

Vectors are microclimatic explanatory variables: soil temperature (soilT), soil water content (soilW), relative air humidity (airH), and air temperature (airT).

Figure 5. CCA for all the recorded macromycetes in the four study sites.

Vectors are environmental explanatory variables: bulk density (bulkD), herbaceous coverage (herbs), rockiness coverage (rock), slope, canopy, moss coverage (moss), litterfall, aspect, and soil pore space filled with water (waterFPS).

Figure 6. CCA for all the recorded macromycetes in the four study sites.

Vectors are vegetation structure explanatory variables: tree maximum height (treemaxH), tree average height (treeavH), tree basal area (treeBA), and tree density (treeDen).