Canopy composition and site are indicative of mineral soil conditions in Patagonian mixed Nothofagus forests

Abstract

& Key message Canopy composition in mixed Patagonian Nothofagus forests has an impact on soil properties like cationic exchange capacity and pH, while most soil variables changed with site [P, cation exchange capacity (CEC), soil moisture (SM), resistance to penetration (R)]. Site conditions and canopy composition need be considered together to better understand the distribution of Nothofagus species. & Context Forests can influence soil development, changing main soil properties by several mechanisms, but this has never been investigated in mixed Nothofagus forests. Such influences can be strongly variable depending on local site conditions, and the interactions between both factors need to be clearly established. & Aims To reveal the effect on physical and chemical mineral soil properties in mixed Nothofagus forests of canopy composition and their interactions with site conditions. & Methods Two sites and three mixed forest types, with different proportion of deciduous-evergreen, were selected in coastal and mountain sites. We evaluated forest structure, litterfall and physico-chemical properties of mineral soil (N = 60), and analyzed these factors with general linear models and multivariate statistics [multi-response permutation procedure (MRPP), principal component analyses (PCA)]. & Results Basal area and litterfall were significantly influenced by forest type × sites. CEC and pH value varied among forests types and sites, but sites also influenced other variables (P, SM, R). Multivariate analyses reveals a much stronger effect of site conditions than that of species mixture. & Conclusion Forest soil studies must consider environmental factors on different spatial scale and canopy species composition to better understand their influence on soil dynamics in mixed Nothofagus forests.

Forest canopy-cover composition and landscape influence on bryophyte communities in Nothofagus forests of southern Patagonia

“…Precipitation was also crucial due to its influence on water storage in soils and environmental moisture. However, the water storage capacity differed between soils of evergreen and deciduous Nothofagus forests [ 24 ], which could generate differences in the soil moisture and therefore differences in the bryophyte cover, as was suggested by Raabe et al [ 7 ]. In addition, air temperature and relative air humidity are considered key drivers in structuring bryophyte communities in different forest types [ 7 , 55 ].…”

“…pumilio and N . betuloides species in the overstory canopy) (see more details on overstory canopy characterization in Toro Manríquez et al [ 23 , 24 ] and Mestre et al [ 25 ]). Similarly, two contrasting landscapes were selected, where these three forest types naturally occur: (i) marine coasts close to the Beagle Channel and (ii) mountainous areas toward the inner island.…”

“…In general, the main soil type in both forest types on these coasts and in the mountains is textured loam, with large granular structures, low usable water capacity and moderate to slow internal and external drainage with a thick organic soil layer [ 29 ]. However, coastal and mountainous soils showed some differences; for example, canopy composition in these forests has an impact on soil properties, but most soil properties are strongly influenced by the landscape (e.g., in comparison to coastal soils, mountainous soils are wetter and richer in N and P) and, to a lesser extent, by the proportion of deciduous and evergreen canopies [ 24 ]. In addition, litterfall (quantity and quality), which determines nutrient cycling in soils, also differs among forest types and landscapes [ 24 ].…”

“…This study was conducted in old-growth Nothofagus forests (>250 years-old) located in the southwestern Tierra del Fuego Island, Argentina (Fig 1), that has not had harvesting or cattle grazing during occur the last 60 years. Three Nothofagus forest types were considered, according to their canopy-layer composition: (i) Np = pure deciduous forests (with > 80% of N. pumilio canopy cover); (ii) Nb = pure evergreen forests (with > 80% N. betuloides canopy cover); and (iii) M = mixed deciduous-evergreen forests (with a similar proportion of N. pumilio and N. betuloides species in the overstory canopy) (see more details on overstory canopy characterization in Toro Manríquez et al [23,24] and Mestre et al [25]). Similarly, two contrasting landscapes were selected, where these three forest types naturally occur: (i) marine coasts close to the Beagle Channel and (ii) mountainous areas toward the inner island.…”

“…Oerst. These tree species grow naturally across the landscape, and some of them (N. pumilio and N. betuloides) can form mixed deciduous-evergreen forests [23,24]. The understory is mainly composed of forbs, grasses and several woody shrub species, where pure deciduous forests and mixed forests present similar species compositions [25].…”