Framework Species Approach Proves Robust in Restoring Forest on Fire Prone Invasive Grass: A Case Study from Panama

Abstract

Grasses and fire pose a major challenge for forest restoration. Here we evaluate a case study of reforestation in an area invaded by the tall invasive grass Saccharum spontaneum in the Panama Canal Watershed. The project objectives were to (1) replace Saccharum with a forest, (2) restore a stratified mixed species forest and (3) sequester carbon. We aimed to compare the practice of forest restoration with a treatment grounded in theory. Therefore, the first species selection method followed business-as-usual: contractors planted any combination of 130 prescribed species. The second method followed the framework species approach, a mixture of 22 species was planted to ensure early shade, create a stratified forest over time, attract seed dispersers, and for their potential to fix N 2. Both treatments showed successful restoration trajectories 8.5 years after planting, they did not differ in structural characteristics (stem density, basal area, aboveground biomass, height, and amount of Saccharum). However, based on the species present, the framework approach shows more potential to become a stratified forest. As the framework approach also withstood fires much better than the business-as-usual approach, we conclude that it improves restoration success in this human-dominated landscape.

Restoration potential of eight tree species from a seasonally dry tropical forest in southeast Piauí, Brazil

“…A method to identify which species to use in these programs is the framework species approach. Originally developed in Queensland, Australia, this method has been successfully used to guide restoration practices in a variety of ecosystems, such as tropical forests in Panama and Thailand (Boeschoten et al, 2020;Waiboonya and Elliott, 2020) to dryland vegetation in Argentina (Pérez et al, 2019). This method involves planting mixtures of 20 to 30 tree species in a single step to identify characteristics pertinent to ecosystem restoration.…”

A perfect storm: ploidy and preadaptation facilitate Saccharum spontaneum escape and invasion in the Republic of Panama

“…The historical record indicates that the spread of S. spontaneum in Panama began within a decade of the arrival of the USDA sugarcane germplasm collection at the CZEG in 1939 (Moore 1948). Although we did not have access to all of the accessions in the historical USDA collection (likely 25-35 accessions;Artschwager 1942;Brandes et al 1938;Price 1957;USDA-GRIN 2009), our Historic dataset includes 21 accessions and is representative of both the geographic range and variation in ploidy of specimens in the germplasm collection at the time (Table 1). Today the S. spontaneum population in Panama represents a single cpDNA haplotype lineage and is genotypically distinct from the majority of samples in the world S. spontaneum germplasm collection which shows high Aitken et al (2018), Price (1957), Sreenivasan and Jagathesan (1975) c Aitken et al (2018), Panje and Babu (1960), Price (1957), Sreenivasan and Jagathesan (1975) d Aitken et al (2018), Brandes and Sartoris (1936), Sreenivasan and Jagathesan (1975) e Aitken et al (2018), Brandes and Sartoris (1936), Panje and Babu (1960), Price (1957), Sreenivasan and Jagathesan (1975) f Brandes and Sartoris (1936), Panje and Babu (1960), Price (1957), Sreenivasan and Jagathesan (1975) genetic diversity and little geographic structuring (Fig.…”

“…Many are large-statured and form monocultures, excluding other species and, in many cases, rapidly transforming the landscapes that they invade (Lambert et al 2014;Canavan et al 2019). In the wet Neotropics, invasive grasses have increased fire regimes (Saltonstall and Bonnett 2012;Williams and Baruch 2000) and inhibited natural regeneration of forest communities across the region (Boeschoten et al 2020;Hooper et al 2005;Jones et al 2004;Wishnie et al 2002;Nepstad et al 1991).…”

The framework species method: harnessing natural regeneration to restore tropical forest ecosystems

“…Outside of Thailand and Australia, inclusion of some large-seeded, dispersal-limited species was mentioned in one study in Hong Kong [79], while keystone species were mentioned in eight publications. When the FSM was trialled in fire-prone northern Thailand, fire resilience was added to the framework species selection criteria described above [10] and later in Argentina [87] and Panama [81].…”