Microsite abiotic conditions and juvenile response under three early successional shrub/tree species in a SEMI‐ARID region

Abstract

In environments with water and nutrient constraints, some early successional shrub/tree species may promote facilitation by ameliorating the microclimate and increasing resource availability. We ask whether early successional semi‐arid shrub/tree species have facilitation effects for other woody species and if they do, which mechanisms are involved and how they affect the water status of juvenile plants. Three early successional woody species; Combretum leprosum, Cenostigma bracteosum and Mimosa tenuiflora, were chosen for investigation. The richness of regenerating woody species and their leaf water potential were used as response variables, while air and soil temperature, leaf area index, humidity and soil attributes were used as explanatory environmental variables. Species growing under the canopy of C. leprosum had better water status and growth at higher soil moisture and lower thermal and solar radiation stress, receiving a facilitative effect. The lower leaf area index, higher radiation and more negative soil water content under the canopy of C. bracteosum in comparison to C. leprosum may have a small negative effect on species richness. M. tenuiflora did not reduce environmental stress, and the species associated with it had low water potential, thus no increase in species richness was detected under its canopy. C. leprosum and C. bracteosum improve the environmental conditions under their canopies and provide favourable microsites for the establishment of other species. The positive effects may be generated by functional traits that modify microclimatic characteristics under the nurse species' canopy and lead to a higher water status of the juveniles growing under it.

Asociación espacial de Nothofagus antarctica y Berberis microphylla: mecanismos de facilitación sobre la regeneración arbórea en sistemas silvopastoriles

“…Los arbustos colonizadores que rebrotan después del fuego (Blackhall et al, 2015;Kitzberger et al, 2016;Landesmann et al, 2021) generan condiciones diferentes bajo su copa que podrían favorecer la germinación y el establecimiento de las especies leñosas en ambientes estresantes (Callaway, 2007;Oliet y Jacobs,2007;Gómez-Aparicio et al, 2004;Veblen et al, 2004;Heinemann y Kitzberger, 2006;Cortina et al, 2011;Mosquera-Losada et al, 2015;Valenzuela et al, 2016;Al-Namazi et al, 2020;Yuan et al, 2019;Arroyo et al, 2021;Parajuli et al, 2021;Chillo et al, 2022;Yang et al, 2022). En zonas áridas los arbustos dan origen a las denominas islas de fertilidad (Maestre et al, 2009b;Eldridge et al, 2011;Perea et al, 2014;Moncayo-Riascos y Gálvez-Cerón, 2018;Navarro-Cano et al, 2019;Karlin et al, 2021;Crockett y Hurteau, 2022;Sales Lucas et al, 2022). Las islas de fertilidad son micrositios que pueden favorecer la sucesión natural al contener semillas y al reducir el estrés ambiental como por ejemplo mayor humedad del aire y mayor hojarasca (Moncayo-Riascos y Gálvez-Cerón, 2018; Karlin et al, 2021).…”

“…Los arbustos poco palatables, especialmente aquellos que poseen espinas (Hanley et al, 2007), favorecen la supervivencia y el crecimiento de plantas que crecen en su cercanía (Callaway et al, 2000;Rebollo et al, 2002;Gómez-Aparicio et al, 2004;Pugnaire et al, 2004;Padilla y Pugnaire, 2006;Smit et al, 2007;López y Cavallero, 2017;Peebles-Spencer y Gorchov, 2017;Bannister et al, 2020;Wang et al, 2021b;Chillo et al, 2022). Por otro lado, como se observó en el Capítulo II y como evidencia la bibliografía, los arbustos pueden disminuir la radiación solar excesiva, la compactación del suelo, amortiguar la temperatura del aire, la temperatura del suelo, entre otras (Veblen et al, 2004;Heinemann y Kitzberger, 2006;Callaway, 2007;Oliet y Jacobs, 2007;Cortina et al, 2011;Mosquera-Losada et al, 2015;Valenzuela et al, 2016;Al-Namazi et al, 2020;Arroyo et al, 2021;Parajuli et al, 2021;Sales Lucas et al, 2022).…”