Extensive clonal propagation and resprouting drive the regeneration of a Brazilian dry forest

Abstract

Woody plant resprouting has received considerable attention in the last two decades as human disturbances continue to encroach on terrestrial ecosystems globally. We examined the regeneration mechanisms of a Caatinga dry forest in the context of slash-and-burn agriculture and resprouting ability of the local flora. We excavated two old fields (from 32) experiencing early forest regeneration dominated by the tree Pityrocarpa moniliformis (Fabaceae) to map clonal propagation and, in parallel, submitted 260 seedlings from 13 woody plant species to experimental clipping. What seemed to be ‘seedlings’ popping up around P. moniliformis stumps and remaining adults actually were condensed sets of root suckers connected via complex networks of long, ramified shallow horizontal roots without taproots. We mapped respectively 39 and 783 connected root suckers, which summed 96 m and 910 m in root length. Regarding the seedlings, 33% resprouted across nine species with resprouting rates varying between 5–100%. Seedling height before clipping positively influenced resprouting vigour. Our preliminary results suggest that the Caatinga dry forest supports a relatively high proportion of resprouting species, some of them able to clonally propagate and playing an ecosystem-level role by responding to early forest regeneration and high abundance/biomass across both regenerating and old-growth forests.

Silvicultural Practices in the Management of Diospyros melanoxylon (Tendu) Leaf Production: Options and Trade-offs

“…The use of fire may not be recommended for increasing tendu leaf production based on our findings, although the delayed fire setting in 2020 may have led to some anomalous results. Fire can have adverse impacts on vegetation community composition, favoring species that can produce root suckers and resprouts at the expense of species that propagate with epicormic sprouts or exclusively through seeds (Kammesheidt 1999 ; Saha and Howe 2003 ; Vanderlei et al 2021 ) and species that favor forest-edge like conditions (Balch et al 2013 ). Our observations on the use of fire are, however, limited by the sample size and clustering of plots.…”

Impoverished woody seedling assemblages and the regeneration of Caatinga dry forest in a human‐modified landscape

“…By assuming that our snapshot captured more than the last recruited seedling cohort (usually from the last rainy season) and included a significant proportion of species attending the assemblages (see Figure S1), our findings indicate that: (1) seedling assemblages represent a limited and sensitive source (i.e., negatively affected by external factors) for adult recruitment and will likely have a limited impact on the structure of future adult assemblages; (2) species recruiting via seedlings are probably the ones able to persist in the system for an extended period of time (e.g., from the previous rainy season or emerged after irregular rain periods) with limited growth and take long periods of time to establish new adult individuals (i.e., slow forest dynamic); and (3) other regeneration mechanisms, such as adult resprouting and vegetative propagation may play a significant role in Caatinga forest regeneration (see Barros et al, 2021; Sampaio et al, 1993; Vanderlei et al, 2021), as observed in different dry forests (Bond & Midgley, 2001; Vieira & Scariot, 2006).…”

“…Accordingly, seedling assemblages reflect the morphological, physiological, and phenological characteristics that allow different species to coexist and persist in response to changes in environmental conditions and biotic interactions (Pérez‐Harguindeguy et al, 2013). In other words, the composition of adult assemblages is expected to be determined by the species whose seedlings are able to endure the abiotic and biotic constraints that limit their survival (Swaine, 1996) or to guarantee their persistence via resprouting (Vanderlei et al, 2021).…”

“…These pressures on seedlings can favor species able to resprout, with forest regeneration marked by this mechanism (Barros et al, 2021; Murphy & Lugo, 1986; Vanderlei et al, 2021; Vieira et al, 2006). However, the combined effects of both water availability and chronic anthropogenic disturbances on seedlings remain poorly investigated, despite their potential impacts on forest regeneration and dynamics in human‐modified landscapes (see Barros et al, 2021; Souza et al, 2019; Vanderlei et al, 2021).…”

“…In other words, the composition of adult assemblages is expected to be determined by the species whose seedlings are able to endure the abiotic and biotic constraints that limit their survival (Swaine, 1996) or to guarantee their persistence via resprouting (Vanderlei et al, 2021).…”