Post-cropping change and dynamics in soil and vegetation properties after forest clearing: Example of the semi-arid Mikea Region (southwestern Madagascar)

Abstract

This study concerns post-cultural dynamics in the semi-arid South-West of Madagascar (Analabo area, near the Mikea Forest). A synchronic comparison was performed on a set of abandoned fields plots aged from 2 to 30 years and on forest and savanna reference ecosystems, located on cambic arenosols developed from same Quaternary dune sands. The studied parameters concerned mainly a few physical and chemical soil properties (density, permeability, compaction, texture, C, N, K, P content). Important changes occur in the post-cultural succession: an increase of the soil density and compaction, and decrease of the soil upper layer permeability. Consequently, slash and burn cultivation leads to a packing and an induration of the soil surface. Results about edaphic indicators have shown that the physical parameters used better discriminate various stages of evolution than the chemical parameters do. The multivariate analysis of soil indicators shows that vegetative succession over 30 years in a forest ecosystem cleared, burnt, cultivated and left, does not lead to features corresponding to a closed-canopy forest but rather to those of a tree savanna with open, mixed woody-herbaceous vegetation. The primary dense dry deciduous regeneration of the primary forest is very low or nil. In the semi-arid SW Madagascar (Analabo region), post-cultural dynamics conditions consists in a savannaformation process, controlled by: (1) the intensity and duration of the disturbance (during the cultivation phase); and (2) the more drastic environmental conditions (including both climate and soil).

Using Utilitarian Plants for Lemur Conservation

“…For humid forests, mango and litchi provide fruit for people and animals and Harungana madagascariensis is fast growing and can quickly cover degraded areas, providing food for birds and lemurs while serving medicinal purposes for humans (Birkinshaw et al 2009;Rakotoarivelo et al 2015;Steffens 2020). Adding Klanderud et al 2010;Leprun et al 2009;Rabenantoandro et al 2007;Raharimalala et al 2010;Styger et al 2007;Zwartendijk et al 2017).…”

“…Over the past century, fallow periods became too short to ensure recovery of vegetation and soil conditions, resulting in increasing pressure on natural resources and declining agricultural productivity. The speed of fallow vegetation recovery and the changes in soil fertility of slash-and-burn cultivation sites has been well documented for a variety of sites (De Wilde et al 2012;Gay-des-Combes et al 2017;Klanderud et al 2010;Leprun et al 2009;Raharimalala et al 2010;Styger et al 2007;Zwartendijk et al 2017). The restoration and transformation of fallow land to more productive permanent agricultural fields often failed, due to the high work load associated with sustainable cultivation techniques (manure and compost management) and further constraints such as limited resources for external inputs and marketing opportunities for agricultural products (Hume 2006).…”

The eco‐evolutionary history of Madagascar presents unique challenges to tropical forest restoration

“…Soil degradation is likely a driving factor in inhibition of both biomass and biodiversity recovery, with post-cultivation soils notably denser and more compact than primary forests (Leprun et al, 2009).…”

Goat Breeding: A Possible Sustainable Way to Manage Xerophytic Thickets in Southwestern Madagascar

“…Post-SBA recovery in dense humid forests [44][45][46][47] and in dense dry forests [48][49][50] is fairly well documented in Madagascar. In contrast, studies on post-SBA recovery of XTs are scarce [35,51].…”