It is not just about time: Agricultural practices and surrounding forest cover affect secondary forest recovery in agricultural landscapes

Abstract

Natural regeneration of forests has significantly led to increased native forest cover in some regions. Several studies have explored the spatial drivers of forest cover increase, yet little is known about their effects on forest structure and species richness and diversity. We quantified the effects of local (forest age, remnant Eucalyptus basal area, slope, soil fertility, and clay content) and landscape drivers (surrounding land use, distance from streams, and surrounding forest cover and its change over time) on the aboveground biomass, species density, and phylogenetic diversity of native trees in second-growth forests. We sampled 44 naturally regenerating forests established on former pastures and abandoned Eucalyptus plantations for 11-46 years in agricultural landscapes of the southeastern Atlantic Forest, Brazil. We used generalized linear mixed effect models to quantify the effect drivers on forest attributes. While only Eucalyptus basal area and proximity to sugarcane plantations had a consistent negative effect on forest biomass, other drivers were among the best models to explain forest attributes, but their effect was variable. Age increased tree biomass but the effect was not consistent. Similarly, species richness and phylogenetic diversity were mainly affected by landscape drivers such as surrounding forest cover. In tropical agricultural landscapes, effective forest recovery requires more than just time, as forest age can be less important in determining forest attributes than human land uses and surrounding native forest cover. Crucially, forest recovery can be improved | 497 CÉSAR et Al. 2 | ME THODS 2.1 | Study region Our study was carried out in the 1,700 km 2 Corumbataí river basin in southeast Brazil, which had 12.4% forest cover remaining in 2016. The Köeppen-Geiger classification of the region's climate through interventions and policies that promote less impactful human activities and enhance existing forest cover.

Dynamics of Natural Regeneration: Implications for Landscape Restoration in the Atlantic Forest, Brazil

“…A long period of regeneration is also critical to allow the vegetation to become a source of propagules within the mosaic of regenerating forest and for sustaining an array of dispersers responsible for spreading the propagules to neighboring forest tracts. We recognize that natural regeneration in other regions or different previous land use may present a lower potential to restore degraded/deforested ecosystems (Stanturf et al, 2001;Holl and Aide, 2011;Chazdon and Guariguata, 2016;Crouzeilles et al, 2017;Holl, 2020;César et al, 2021), which can limit its application in specific cases.…”

Linking land-use and land-cover transitions to their ecological impact in the Amazon

“…It is conceivable that colonization of open-habitat species has compensated for the loss of forest species ( 52 ), and a stricter definition of forest species (e.g., forest specialists) would likely reveal stronger effects of fires and logging ( 22 ). Besides the intrinsic nature of the different variables we included in our study, this high variability can also result from differences in the intensity, frequency, and time since the transition happened, as well as the specific context of the landscape [e.g., the extent of surrounding forest cover ( 53 , 54 )].…”

Nine actions to successfully restore tropical agroecosystems

“…There are high chances that restoring tropical agroecosystems will bring ecological success because, compared with temperate areas, plant growth rates in the tropics are fast, allowing relatively rapid recovery of floral structural complexity and diversity [7]. Also, in many tropical regions, large areas of intact natural habitat remain [29], possibly accelerating the recovery of agroecosystems through spillover of species and ecosystem services [30]. Further, 'Green Revolution' approaches to intensifying agriculture have been implemented only relatively recently and variably across the tropics [25], potentially making it easier to reverse their impacts [31].…”