Effects of forest preservation, livestock exclusion, and use of shrubs as potential nurses on planting success of an endangered tree

Abstract

Domestic livestock are widespread in seasonally dry forests, likely causing forest degradation and limiting tree seedling establishment. Shrubs can play an important role in facilitating tree regeneration, by protecting trees from livestock damage and ameliorating unfavorable abiotic conditions. We aimed at disentangling the relative contribution of grazing exclusion, long‐term forest conservation, and the potential facilitation effect of shrubs on the performance of saplings of the native tree Kageneckia lanceolata. We planted 400 saplings in grazed and ungrazed areas situated both in a preserved and a degraded forest. In each situation, we established planting plots in three accompanying vegetation treatments: herbs, a nonleguminous spiny shrub and a leguminous spiny shrub. Survival of 3‐year‐old saplings was 10‐fold higher in the preserved than in the degraded forest and 2‐fold higher in the ungrazed than in the grazed site. Differences in survival among accompanying vegetation treatments were much smaller than between grazing treatments. Survival significantly increased with increasing protection by shrubs only in the degraded site. Sapling growth patterns were fairly similar to survival patterns, with no growth in the degraded forest, except for limited growth under both shrubs in the ungrazed site. We conclude that, in selecting plantation sites for the study species, forest condition and grazing exclusion should be prioritized over microsite selection based on neighboring vegetation.

Large‐scale facilitative effects for a single nurse shrub: Impact of the rainfall gradient, plant community and distribution across a geographical barrier

“…Then, it is evident that the frequent positively associated species in the western range correspond all to species from sclerophyllous forest. In addition, the results of our study align with previous findings in the eastern range, such as those in Córdoba province (Torres et al, 2021) and at the Paraná River mouth (Pozo Inofuentes & Säumel, 2022),…”

“…Giorgis et al, 2013;Karlin et al, 2016), and incipient studies show similar positive effects of V. caven on other plants as found in Chile. For example, V. caven was found to increase the survival of the endangered tree Kageneckia lanceolata in both grazed and ungrazed conditions (Torres et al, 2021).…”

“…Among nurse species, woody shrubs are typically recognized as a prominent life form for producing positive plant–plant interactions (Filazzola & Lortie, 2014). This plant group can increase establishment compared to not only open sites but also other woody species (Root‐Bernstein et al., 2017; Torres et al., 2021). In particular, many shrubby Fabaceae are well known for their nurse effects on other plant species (Flores & Jurado, 2003; Smit et al., 2008; Valiente‐Banuet & Verdú, 2007).…”

“…Giorgis et al., 2013; Karlin et al., 2016), and incipient studies show similar positive effects of V. caven on other plants as found in Chile. For example, V. caven was found to increase the survival of the endangered tree Kageneckia lanceolata in both grazed and ungrazed conditions (Torres et al., 2021). In addition, the regeneration of several tree species was higher under V. caven than under other legume species from a subtropical grassland (Pozo Inofuentes & Säumel, 2022).…”

Setting large- and medium-sized mammal restoration goals in a last mountain Chaco remnant from central Argentina

“…In contrast to the scarcity of native herbivores, our estimation of non-native herbivore biomass (4356 kg km −2 ) is similar to wild herbivore reference biomass, as calculated using data from Africa, and higher when calculated using global data or data from the American continent. In our study area, cattle and horses were the main exotic mammals, and their known negative effects include delaying forest regeneration (Torres and Renison 2016;Barberá et al 2018;Torres et al 2021) and reducing other mammal densities due to direct competition for resources or changes in woody vegetation (Nanni 2015;Periago et al 2015;Puechagut et al 2018). The wild boar is an invasive species whose negative global impacts are well-known (Barrios-Garcia and Ballari 2012), and possibly a direct competitor to the only remaining native herbivore, the collared peccary (Barrios-Garcia and Ballari 2012).…”