Search

Premise: Functional traits reflect species' responses to environmental variation and the breadth of their ecological niches. Fagus grandifolia and Oreomunnea mexicana have restricted distribution in upper montane cloud forests (1700–2000 m a.s.l.) in Mexico. These species were introduced into plantings at lower elevations (1200–1600 m a.s.l.) that have climates predicted for montane forests in 2050 and 2070. The aim was to relate morphological leaf traits to the ecological niche structure of each species. Methods: Leaf functional traits (leaf area, specific leaf area [SLA], thickness, and toughness) were analyzed in forests and plantings. Atmospheric circulation models and representative concentration pathways (RCPs: 2.6, 4.5, 8.5) were used to assess future climate conditions. Trait–niche relationships were analyzed by measuring the Mahalanobis distance (MD) from the forests and the plantings to the ecological niche centroid (ENC). Results: For both species, leaf area and SLA were higher and toughness lower in plantings at lower elevation relative to those in higher‐elevation forests, and thickness was similar. Leaf traits varied with distance from sites to the ENC. Forests and plantings have different environmental locations regarding the ENC, but forests are closer (MD 0.34–0.58) than plantings (MD 0.50–0.70) for both species. Conclusions: Elevation as a proxy for expected future climate conditions influenced the functional traits of both species, and trait patterns related to the structure of their ecological niches were consistent. The use of distances to the ENC is a promising approach to explore variability in species' functional traits and phenotypic responses in optimal versus marginal environmental conditions. [ABSTRACT FROM AUTHOR]

Greenfall leaves caused by hailstorms may represent a resource pulse of nutrients. We determined the contribution of greenfall versus senescent leaves to total litterfall production, carbon, nitrogen and phosphorus input to the system, and leaf decomposition rate. Litterfall was collected monthly for three years in two cloud forests (F1, F2) and a restoration planting area (R) in Veracruz, Mexico. Two fortuitous hailstorms occurred in the second year. Leaf decomposition rate was determined in all three sites but did not differ across them. Total annual litterfall, excluding greenfall, was 10.0, 10.1, and 7.7 Mg ha−1 y−1 for F1, F2, and R, respectively. Senescent leaves represented 65% of the litterfall, while greenfall leaves increased the annual leaf biomass component of the litterfall by 12%. Concentrations of carbon, nitrogen, and phosphorus were 2.3, 5.7, and 18.1% higher, respectively, in greenfall than in senescent leaves. Greenfall increased the annual input of C, N, and P by 12, 13, and 14%, respectively. Despite their short duration (approximately 70 minutes), the hailstorm events generated a substantial contribution of greenfall leaves and a source of extra C, N, and P, since these leaves decompose and are incorporated into the cloud forest system. [ABSTRACT FROM AUTHOR]

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 [...]