Acacia caven nurses endemic sclerophyllous trees along a successional pathway from silvopastoral savanna to forest

Abstract

Citation: Root-Bernstein, M., R. Valenzuela, M. Huerta, J. Armesto, and F. Jaksic. 2017. Acacia caven nurses endemic sclerophyllous trees along a successional pathway from silvopastoral savanna to forest. Ecosphere 8(2):e01667. 10.1002/ecs2.1667Abstract. The successional pathways linking the Acacia caven-dominated savanna habitat "espinal" and the closed sclerophyllous forest of central Chile have long been debated. Previously, espinal was considered an invasive degradation of closed forest that tended toward desertification, could not be restored to forest, and had little ecological value. Recent GIS (Geographical Information System) research on land-use change has, however, detected apparent regeneration of sclerophyllous forest from espinal. This suggests that there is a successional path linking espinal and sclerophyllous forest. Here, we used surveys of transects in espinals and espinal-sclerophyllous forest transitions to ask whether (1) A. caven is an invasive species or a pioneer species, (2) forest regenerates by sclerophyllous trees "filling in" spaces between A. caven individuals, and then shading them out (plant-plant competition), or (3) forest regenerates by plant-plant facilitation between A. caven and other species, and (4) how current and historical management and condition affect these potential successional mechanisms. We find that A. caven establishes primarily in full sunlight and is unlikely to degrade forests via invasion. We also find, for the first time, evidence that A. caven is a nurse tree to several sclerophyllous forest tree-beneficiary species. Measurements of the under-canopy microhabitat of A. caven, compared to Lithraea caustica, another possible nurse species, suggest that it provides a balance between shade and soil moisture retention, making it a regeneration site not only for directed bird-dispersed seeds but also for undirected wind-dispersed ones. Conservation and restoration of espinals, especially in drier areas, could provide capacity for future dynamic successional pathways in central Chile.

Nurse species facilitate persistence of dry forests in agricultural landscapes in Uruguay

“…Similar studies emphasize the provision of shade and reduction of light intensity by nurse trees (Abdallah & Chaieb, 2012), resulting in lower seedling mortality compared to open microhabitats (Manning et al, 2006). The nurse trees analyzed in this study, Prosopis spp., and Vachellia caven , are also able to improve soil conditions for regeneration as a result of their nitrogen fixation capacity (Root‐Bernstein et al, 2017). Isolated trees of Vachellia caven improve soil fertility and herbaceous biomass in Uruguayan grasslands (Bernardi et al, 2016).…”

Endophytic Fungi Isolated from Plants Growing in Central Andean Precordillera of Chile with Antifungal Activity against Botrytis cinerea

“…Species from genus Alternaria have been described as saprobic, endophytic, and pathogenic [ 45 ]. Many species of Alternaria isolated as endophytic produce antifungal compounds [ 39 ]. Some of these species have been reported with activity against B. cinerea [ 40 , 46 , 47 ].…”

“…L. caustica (litre) is an endemic tree of Chile and E. chiloensis is an endemic columnar cactus species widely distributed in north-central Chile that inhabits mainly equatorial-facing slopes in semiarid environments [30,38]. A. caven is a native tree found in several countries in South America [39]. Although endemic or native plants of this region were used in this work, the isolated fungi Alternaria spp.…”

Respuestas morfo-fisiológicas de plantas de Lithraea caustica (Anacardiaceae) sometidas a restricción hídrica controlada

“…Mol. (espino), matorrales más xéricos que han sido considerados como etapas pioneras de la sucesión secundaria (Root-Bernstein et al 2017).…”