The influence of canopy-layer composition on understory plant diversity in southern temperate forests

MESTRE, LUCIANA; TORO MANRÍQUEZ, MÓNICA; SOLER, ROSINA; HUERTAS-HERRERA, ALEJANDRO; MARTÍNEZ PASTUR, GUILLERMO; LENCINAS, MARÍA VANESSA

Forest Ecosystems

SPRINGER

Año: 2017 vol. 4 p. 1 - 13

Background:Understoryplants represents the largest component of biodiversity in most forestecosystems and plays a key role in forest functioning. Despite theirimportance, the influence of overstory-layer composition on understory plantdiversity is relatively poorly understood within deciduous-evergreenbroadleaved mixed forests. The aim of this work was to evaluate how treeoverstory-layer composition influences on understory-layer diversity in threeforest types (monospecific deciduous Nothofaguspumilio (Np),monospecific evergreen Nothofagusbetuloides (Nb), and mixed N. pumilio-N. betuloides (M) forests), comparing also between twogeographical locations (coast and mountain) to estimate differences atlandscape level.Results:Werecorded 46 plant species: 4 ferns, 12 monocots, and 30 dicots. Canopy-layercomposition influences the herb-layer structure and diversity in two differentways: while mixed forests have greater similarity to evergreen forests in theunderstory structural features, deciduous and mixed were similar in terms ofthe specific composition of plant assemblage. Deciduous pure stands were themost diverse, meanwhile evergreen stands were least diverse. Lack of exclusivespecies of mixed forest could represent a transition where evergreen anddeciduous communities meet and integrate. Moreover, landscape has a majorinfluence on the structure, diversity and richness of understory vegetation ofpure and mixed forests likely associated to the magnitude and frequency ofnatural disturbances, where mountain forest not only had highest herb-layerdiversity but also more exclusive species. Conclusions: Our study suggests that mixed Nothofagus forest supports coexistence of both pure deciduousand pure evergreen understory plant species and different assemblages incoastal and mountain sites. Maintaining the mixture of canopy patch typeswithin mixed stands will be important for conserving the natural patterns of understoryplant composition in southern beech mixed forests.