Diversity of macromycetes determined by treespecies, vegetation structure, and microenvironment in tropical cloud forests in Veracruz, Mexico

Tropical montane cloud forests (TMCFs) have high levels of plant and fungal diversity. We examined whether macromycete alpha and beta diversity were associated with woody plant diversity, forest structure, or microclimate, in four TMCFs at lower (1240-1440 m) and upper altitudes (1790-1900 m) in Veracruz, Mexico. Every 2 weeks during the growing season, macromycetes were collected from ten 10 m x 10 m permanent plots per site, and air and soil temperature and humidity were measured. In total, 2059 macromycetes (509 species) and 678 woody plants (63 species) were recorded. Macromycete diversity (Shannon Index) values of the two sites located in lower forests were higher than in upper sites. Beta diversity (Jaccard index) indicated high turnover among sites and sampling times. Macromycete richness was negatively correlated with overstorey tree richness, understorey vegetation structure, and air temperature, but was positively correlated with air humidity and soil water content and altitude. Ordinations separated lower from upper altitude forest sites. Changes in composition and abundance of macromycete species with altitude were explained by precipitation, temperature, and understorey vegetation structure, while soil water content effect changes within a growing season. Results imply that understorey vegetation structure is a more important aspect for macrofungal diversity management than for woody plant diversity. Key words: altitude, alpha diversity, beta diversity, macromycete species, microclimate, tree species, tropical montane cloud forest. Les forets tropicales montagneuses ombrophiles (TMCF) comportent une forte diversite de plantes et de champignons. Les auteurs ont examine si les diversites alpha et beta des macromycetes s'associent avec la diversite des plantes ligneuses, la structure de la foret, ou le microclimat dans quatre TMCF, aux basses (1240-1440 m) et hautes altitudes (1790-1900 m) a Veracruz, au Mexique. A toutes les 2 semaines au cours de la saison de croissance, ils ont recolte les macromycetes sur 10 parcelles permanentes de 10 m x 10 m, et ont mesure la temperature et l'humidite du sol. Au total ils ont observe 2059 macromycetes (509 especes), et 678 plantes ligneuses (63 especes). Les valeurs de diversite des macromycetes (indice de Shannon) sur les deux sites localises dans les forets les plus basses s'averent plus grandes que celles obtenues sur les sites plus eleves. La diversite; beta (index de Jacquard) indique une forte rotation entre les sites et les periodes de recoltes. La richesse en macromycetes montre une correlation inverse avec la richesse en especes ligneuses de la canopee, la structure de la vegetation de sous-bois, et la temperature de l'air, mais une correlation positive avec l'humidite de l'air et la teneur en eau du sol ainsi que l'altitude. L'ordination separe les sites forestiers selon l'elevation. On explique les changements de la composition et de l'abondance des especes macromycetes avec l'altitude par la precipitation, la temperature et la structure de la vegetation de sous-bois, alors que les effets de teneur en eau du sol changent au cours de la saison de croissance. Les resultats impliquent que la structure de la vegetation de sous-bois est un aspect plus important pour l'amenagement de la biodiversite macrofongique que la diversite des plantes ligneuses. Mots-cles: altitude, diversite alpha, diversite beta, especes macromycetes, microclimat, especes arborescentes, forets tropicales montagneuses ombrophiles. [Traduit par la Redaction]
Introduction As mutualists, decomposers, and pathogens, fungi are of great importance in forest ecosystems (Schmit and Mueller 2007); however, the relationships between fungal diversity and vegetation type, plant diversity, and [...]