Microclimatology and ecophysiology of the urban vegetation of a city with tropical climate modified by altitude in Mexico

Abstract

Background. Environmental conditions in edges of vegetation fragments affect life cycle characteristics of the native biota (edge effect). We evaluated the edge effect on two Bursera species, which are representative of the mature community of the tropical deciduous forest (TDF) in Mexico. Hypothesis. We expected a population structure reflecting the affectation to reproduction, survival and growth in the edges of TDF fragments. Studied species. Bursera fagaroides, B. palmeri. Study site and years of study. Querétaro (Qro.), Apaseo el Grande (Gto.), México. Field survey: May-September 2012. Methods. Within each of nine TDF fragments, we drew plots in two environmental contrasting conditions (edge and interior), between which we compared the density, population structure and reproductive success of the two Bursera species, as well as estimators of the solar radiation and soil compaction. Results. Solar radiation and soil compaction were not different between environmental conditions. In both species density of individuals was larger in the edge, where individuals with middle and large sizes were predominant. Reproductive potential of individuals, and the viability and germination of their seeds were similar between edge and core environments. Conclusions. Density and population structure showed a congruent variation with higher rates of recruitment, growth and survival in the edge environment, which could have been present under initial conditions of greater incidence of radiation in the edges. The similarity currently observed in the solar radiation between edge and core areas of fragments, could be a result of the fast recovery of the canopy under conditions of higher light incidence in edges. Key words: Bursera fagaroides, Bursera palmeri, dioecious species, germination, tropical deciduous forest.Efecto de borde sobre la estructura poblacional y el éxito reproductivo de dos especies de Bursera. Resumen Antecedentes. Las condiciones ambientales en los bordes de los fragmentos de vegetación afectan las características del ciclo de vida de la biota nativa (efecto de borde). Evaluamos el efecto de borde en dos especies de Bursera, las cuales son representativas de la comunidad madura del bosque tropical caducifolio (BTC) en México. Hipótesis. Esperábamos una estructura poblacional que reflejara la afectación de la reproducción supervivencia y crecimiento en los bordes de los fragmentos de BTC. Especies en estudio. Bursera fagaroides, B. palmeri. Sitio de estudio y fechas. Querétaro (Qro.), Apaseo el Grande (Gto.), México. Trabajo de campo: mayo-septiembre 2012. Métodos. Dentro de cada uno de los nueve fragmentos de BTC, trazamos parcelas en dos condiciones ambientales contrastantes (de borde e interior), entre las que se comparó la densidad, estructura de la población y el éxito reproductivo de las dos especies de Bursera, así como estimadores de la radiación solar y la compactación del suelo. Resultados. La radiación solar y la compactación del suelo no fueron diferentes entre las condiciones ambientales....

Ecophysiological Vulnerability to Climate Change in Mexico City’s Urban Forest

“…This response showed a higher g S sensitivity to VPD and ψ compared to T A and PAR. Differences in stomatal sensitivity found here may be caused by different microclimates at each study site, which could cause acclimatization of stomata to the urban environment (Barradas et al, 2016). Stomatal responsiveness could also be an adaptation (i.e., protective of water loss) related to different management practices (e.g., irrigation) at each site.…”

“…It is worth noting that P. alba had a better g S performance than P. deltoides, showing that other factors rather than phylogeny, may improve species performance, such as plasticity and climate of origin (Nicotra and Davidson, 2010;Du et al, 2019). However, studies in tropical areas showed that phenomenological models, such as the boundary line analysis, are site-specific (Barradas et al, 2004). Also, for the multiplicative model, we used input data derived from meteorological stations from Mexico City; a different approach might be using modeled meteorological data (e.g., PRISM).…”

“…The boundary-line analysis assesses the relationship between g S and climatic/environmental and physiological variables (i.e., T A , PAR, VPD, ψ). From this analysis, graphs are generated representing the optimal stomatal response to a given selected variable (Jarvis, 1976;Fanjul and Barradas, 1985;Jones, 1992;Barradas et al, 2004;Esperon-Rodriguez and Barradas, 2014). The analysis of the effect of each variable on stomatal conductance is determined with simple models that are referred to as boundary-line functions.…”

“…These simple models consist of the selection of data from a probable upper limit represented by a cloud of points in each graph made by plotting g S as a function of any driving variable (i.e., T A , PAR, VPD, ψ). This analysis has three assumptions: (1) the boundary-line function represents the optimal response of g S to the selected variable (e.g., T A ); (2) the points that fall below the selected function are the result of a change in any of the other variables (e.g., PAR, VPD); and (3) it assumes no synergism at the boundary (Jarvis, 1976;Fanjul and Barradas, 1985;Jones, 1992; Ramos-Vázquez and Barradas, 1998;Barradas et al, 2004; Figure 2).…”

Assessing the vulnerability of Australia’s urban forests to climate extremes

“…protected slopes and gulleys). Furthermore, microclimate can alter species’ ecophysiology and thus their ability to cope with climate change (Barradas, Ruiz‐Cordova, & Esperón‐Rodríguez, ). Whenever possible, a more detailed climate assessment considering local microclimate should be used to develop urban planning and management actions.…”