Facilitation and edge effects influence vegetation regeneration in old‐fields at the tropical Andean forest line

Abstract

Questions: Do local plant-plant interactions and facilitation play an important role in vegetation dynamics after disturbance in the high tropical Andes? In particular, does the dominant shrub Baccharis prunifolia have an effect on microclimate and local vegetation structure within old-fields at the upper forest line? Does distance from the border of the surrounding forests also influence community structure within fallow plots? Is there an interaction between facilitation and edge effects on vegetation regeneration?Location: Gavidia Valley, Sierra Nevada de M erida, Venezuela.Methods: Plant cover, species richness and community structure were compared in circular micro-plots placed under the canopy of B. prunifolia shrubs and in open areas (12 micro-plots in each case) both near and far from the forest border within two 10-12 yr successional plots at 3400 m a.s.l. (a total of 96 micro-plots). Additionally, topsoil temperature was monitored for 1 mo in the four situations under study.Results: Average and maximum temperature and temperature amplitudes were lower under the canopy of B. prunifolia shrubs than in open areas; this effect being more marked far from the forest edge. Species richness, vegetation cover and the density of dominant forest trees were higher under the shrubs' canopy than in the inter-shrub spaces. The proximity to the edge of the surrounding forest also had a positive effect on species richness, with no significant interaction with the local sampling situation (under shrub vs outside). Conclusions:Our results suggest that both facilitation and edge effects influence the effectiveness of vegetation regeneration within old-fields in the high tropical Andes. Consequently, these processes should be considered for interpreting vegetation dynamics in environmental change scenarios at the tropical mountain tree line and for the design of ecological restoration strategies in these high-diversity ecotones, which have been subjected to large-scale anthropogenic transformations in recent decades.

Recovery of floristic diversity and basal area in natural forest regeneration and planted plots in a Costa Rican wet forest

“…, Cole ), unsuitable microsites for seed establishment (Holl , Holl & Aide ), and competition from established species (Duncan & Chapman , but see Elgar et al . , Bueno & Llambí ). Natural regeneration is often promoted in state‐owned or private protected areas, or in regions where landowners have financial limitations that preclude active restoration (Parrotta et al .…”

Modelling the effect of temperature changes on plant life-form distribution across a treeline ecotone in the tropical Andes

“…Colours represent the percent cover from blue (low cover) to red (high cover). Llambí et al 2013;Bueno and Llambí 2015). In addition, establishing a higher number of replicate transects, distributed over a wider region could be important to obtain a more representative set of independent samples and to allow the validation of the exploratory models presented here against an independent data set.…”

“…Facilitation by shrubs might play a role in seedling establishment outside of the 625 forest by providing the necessary micro-climatic conditions (García-Cervigón et al 2012;Cáceres et al 2015;Ramírez et al 2015). Different pieces of evidence suggest that this phenomenon may be important at the tropical treeline ecotone 630 (González et al 2011;Llambí et al 2013;Rehm and Feeley 2013;Bueno and Llambí 2015). All of this would agree with scenarios (as the one suggested by our modelling exercise) in which the elevation advance of forest over the páramos is 635 initiated by the establishment of individual pioneer trees outside the treeline border, prior to the formation of a closed canopy, facilitating the subsequent colonisation of other tree species dependent on the more favourable conditions within closed forests 640 (Rehm and Feeley 2013;.…”

Vegetation Conditions in Sacred Compounds at Myanmar’s Bagan Cultural Heritage Site

“…Enrichment of plant nutrients in the upper soil layer of the cultivated land is a factor that can favor the incidence of annual plants shortly after abandonment, then perennial growths later [57,58]. The shrub-hosting patches also create habitat for dispersed seeds of woody species, which later grow into woody vegetation [59,60].…”