Ecology and conservation of threatened plant species
Keywords: coexistence, competition, demography, facilitation, functional traits, invasive, plant-plant interactions, rarity
The conservation of vulnerable species requires a comprehensive understanding of the population dynamics and the environmental factors that influence species long-term persistence and extinction vulnerability. I am interested in the mechanisms promoting the coexistence and long-term persistence of vulnerable species (i.e. rare or endangered) and other species of concern (i.e. invasive). Currently, I am working with a globally rare, endemic and endangered gymnosperm (cycad) species in NW Mexico under the advising of Dr. Martin Dovciak. Although key reproductive and physiological traits give angiosperms competitive advantage over gymnosperms in many ecological settings, both plant groups frequently coexist within the same habitats. I seek to understand how an ancient gymnosperm persists within angiosperm-dominated communities. In this context, I am studying 1) the effects of the environment and demography on the persistence of the cycad Dioon sonorense, 2) coexistence mediated by ontogenetic shifts in plant-plant interactions, including both competition and facilitation at the inter- and intraspecific level, and 3) differences in functional traits potentially promoting the coexistence of Dioon sonorense and co-occurring angiosperms along environmental gradients (elevation and soil nutrients).
Our results, so far, suggest that at least three intrinsic factors are threatening the long-term persistence of this rare species: small adult population sizes, low-quality habitat, and, possibly, the combined effect of low fecundity and recruitment. We discuss their potential implications for the persistence of the rare cycad D. sonorense within a framework of multiple demographic strategies and propose guidelines for a conservation and recovery plan here --> Alvarez-Yepiz et al. 2011.
Vegetation-envionment relationships along altitudinal gradients
Keywords: climate change, elevation, global warming, precipitation, soil, temperature, vegetation structure and composition
Ecologists have long been interested in the relationship between community composition and environmental factors such as topography, soil and climate. I am interested in the local and regional factors driving community assembly along environmental gradients. The relationship between vegetation and climate is currently under intense research since global climate change and its environmental and social implications have become one of the defining issues of national and international research and policy-making. Along with Dr. Martin Dovciak (P.I.) and Dra. Guadalupe Williams-Linera, I am working on a project to understand vegetation-environment relationships and climate change effects on North American vegetation and ecotones (i.e., tropical montane cloud forests in Mexico, montane boreal forests of eastern US). We hope to improve our knowledge of climate-vegetation interactions across tropical, temperate and boreal ecosystems and provide new insights into the conservation and management of vulnerable areas of high conservation value.
Ecology of tropical dry forests: disturbance dynamics and recovery patterns
Keywords: anthropogenic and natural disturbance, biodiversity, community structure, functional traits, land use, soil, succession
The transformation of the tropical dry forest (TDF) in the Neotropics has been mainly related to anthropogenic disturbance such as slash-and-burn agriculture and natural disturbance such as hurricanes. Post-disturbance TDF recovery leads to secondary forests usually dominated by legume plant species (e.g. Acacia, Mimosa). Information documenting these recovery patterns is still scarce. So, under the guidance of my Master's advisor Dra Angelina Martinez-Yrizar at Instituto de Ecologia-UNAM, I studied changes in vegetation structure and soil properties related to land use history of old-growth and secondary tropical dry forests in northwestern Mexico. Our results imply that a) chronic anthropogenic disturbance (i.e. cattle grazing) can homogenize forest composition in forest fragments and decrease stem density, b) overall plant species distribution in the study area (Sierra de Alamos-Rio Cuchujaqui Reserve) is highly correlated with soil cation exchange capacity (CEC), and c) secondary forests accumulate aboveground biomass relatively fast despite low soil fertility (i.e. low CEC), and thus CEC might be a useful indicator of soil recovery and..., read more here --> Alvarez-Yepiz et al. 2008.