Understorey vegetation gradient in a Eucalyptus grandis plantation between a savanna and a semideciduous forest

Abstract

Background: Plant community assemblage is influenced by many factors, including soil characteristics and the arrival of diaspores from surrounding areas. These factors may be especially important in transition areas, leading to spatial gradients in the plant community. Methods: This study was performed in the understorey of an abandoned Eucalyptus grandis W. Hill ex Maiden plantation between a savanna and a forest, 490 m apart, in south-eastern Brazil. This study assessed whether the spatial variation in several variables related to the understorey's structure and composition is best described by linear or non-linear (quadratic) models. The linear model would indicate a gradient between the two vegetation types, whereas the quadratic model would indicate a stronger effect of the plantation's edges. Results: There was a gradient in species composition between the two edges of the plantation. Mean vegetation height was greatest at the savanna edge and lowest in the centre of the plantation. The total number of individuals per plot and the phylogenetic diversity decreased with distance from the savanna edge. Different patterns were observed for different dispersal syndromes, with animal dispersal being more common at the savanna edge, wind dispersal in the centre of the plantation and self dispersal at the forest edge. Conclusions: The greater number of individuals at the savanna edge may indicate that dispersal and arrival of diaspores are the most important factors influencing community structure and composition of the understorey of this abandoned E. grandis plantation, with most propagules coming from the savanna area. The smaller vegetation height in the centre of the fragment may also indicate older colonisation at the edges. Therefore, in addition to highlighting the recovery potential of undergrowth beneath abandoned Eucalyptus spp. plantations, these results show that this recovery is spatially heterogeneous and that dispersal plays a large role in it. This should be taken into account in restoration projects. The authors recommend careful consideration before removing regenerating Eucalyptus spp. trees as part of the site restoration. Instead the focus should be on the recovery potential of the undergrowth, with gradual removal of Eucalyptus trees, if necessary.

Environmental filtering is the main assembly rule of ground beetles in the forest and its edge but not in the adjacent grassland

“…Therefore, incorporating the functional and phylogenetic relatedness of community-forming species may enhance our understanding of the studied community (Cadotte et al, 2010;Swenson, 2013;Magura, 2017). Several recent edge-related studies sought such understanding using functional (Barbaro et al, 2014;Ma & Herzon, 2014), phylogenetic (Dodonov et al, 2014;Peralta et al, 2015), or combined (Luza et al, 2015) approaches.…”

Analysis of effectiveness of three forest interventionist techniques and proposal of a new and integrated model of forest restoration

“…For example, clear cutting and comparatively short rotations favor the occurrence of ruderal plant species (i.e., species able to survive on inhospitable and/or disturbed habitats), whereas some long-lived climax species may not be present [34]. This fact does not occur in the abandonment area due the ceasing of management actions [13].…”

“…Tree plantations reduce ecological health compared to natural forests. After tree harvest when the management of such areas changes A c c e p t e d M a n u s c r i p t 4 from production to conservation, ecological restoration techniques may be preferred rather than "doing nothing" to more rapidly return to of the environmental conditions found in adjacent natural forests [13].…”

“…According to the level of degradation and distance from healthy forested fragments, degraded areas might respond differently depending on the application of different restoration techniques. In forest plantations, the soils and vegetation usually differs from their natural conditions [13,15]. Currently, we do not completely understand how these environmental features are modified after the application of ecosystem restoration techniques.…”

Cerrado natural regeneration in understory of Eucalyptus sp. stands, in the Federal District, Brazil

“…In this context, studies on the natural regeneration in the understory of forests with exotic species have demonstrated that these stands are, most of the times, a biodiversity redoubt (Alencar et al, 2011;Venzke et al, 2012;Dadonov et al, 2014), in which spontaneous native species of the Cerrado can be used as a starting point for restoration actions. On the above, this study aimed to evaluate the natural regeneration of the understory eucalyptus stand and to investigate environmental factors that can be related to the establishment of this vegetation, since this information could subsidy actions and strategies of restauration that consider the use of the natural regeneration.…”