Treesearch

The concept of isohydry/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species level measures of isohydry/anisohydry exist at a few locations, ecosystem‐scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku‐Band backscatter from QuikSCAT) and passive (X‐band vegetation optical depth (VOD) from Advanced Microwave Scanning Radiometer on EOS Aqua) microwave satellite data to estimate global ecosystem isohydry/anisohy...

Climate change is expected to lead to increases in drought frequency and severity, with deleterious effects on many ecosystems. Stomatal responses to changing environmental conditions form the backbone of all ecosystem models, but are based on empirical relationships and are not well-tested during drought conditions. Here, we use a dataset of 34 woody plant species spanning global forest biomes to examine the effect of leaf water potential on stomatal conductance and test the predictive accuracy of three major stomatal models and a recently proposed model. We find that current leaf-level...

Stable stratification of the nocturnal lower boundary layer inhibits convective turbulence, such that turbulent vertical transfer of ecosystem carbon dioxide (CO2), water vapor (H2O) and energy is driven by mechanically forced turbulence, either from frictional forces near the ground or top of a plant canopy, or from shear generated aloft. The significance of this last source of turbulence on canopy flow characteristics in a closed and open forest canopy is addressed in this paper. We present micrometeorological observations of the lower boundary layer and canopy air space collected on...

Post-dispersal seed predators contribute substantially to seed loss across many ecosystems. Most research has focused on understanding sources of variation in seed loss, without appreciating the implications of seed predation for plant coexistence, community assembly and broader community theory. Meanwhile, research aimed at understanding coexistence and community assembly processes in plant communities has focused on axes of dispersal and resource competition and the traits influencing these processes, without accounting for the role of generalist seed predators.

The recent development of an interagency strategy to monitor wilderness character, Keeping It Wild 2: An Updated Interagency Strategy for Monitoring Wilderness Character Across the National Wilderness Preservation System (Landres et al. 2015), allows on-the-ground managers and decision makers to assess whether stewardship actions for an individual wilderness are fulfilling the legislative mandate to “preserve wilderness character.” By using credible data that are consistently collected, one can assess how wilderness character changes over time and evaluate how stewardship actions affect...

Abiotic stresses such as drought, are the main factors for forest declines globally. There is therefore an increasing interest in understanding the mechanisms underlying tree adaptations and survival to water deprivation. Angiosperm tree species demonstrate an amazing phenotypic plasticity. They sense and respond to adverse changing environmental conditions via a series of physiological, cellular, and molecular processes which are under a tight genetic control. In this book chapter, first we present some key morphological and anatomical features adopted by angiosperm tree species to...

Forest tree genomics has made enormous strides in recent years, by describing the expression and function of genes influencing tree growth and development, and even sequencing the entire genomes of select “model” tree species. We believe that the next chapter of forest tree genomics will focus on cross-species comparative approaches, which will have the ability to provide fundamental new insights into the unique biology and evolutionary history of tree species. Angiosperm trees in particular are fascinating in light of evolution. Angiosperm trees represent the extensive genome evolution,...

The major goal of my dissertation was to understand the effect of urban development on biodiversity conservation in Puerto Rico. To accomplish this goal I: 1) described how much and what biodiversity occurs inside the network of terrestrial protected areas, 2) quantified pressure from urban development and human population around protected areas, and 3) assessed how urban development affects the distribution of anurans and reptiles along an urban-rural gradient

Chapter I of this thesis collects general information of green roofs and evaluates the principles of this topic. It covers GR description, design, potential benefits, and climate change. The chapter also includes information about the green roofs in the tropical zones around the globe, and more specifically in Puerto Rico. In Chapter II a vegetation analysis of 4 GRs in San Juan, Puerto Rico was undertaken. The International Institute of Tropical Forestry (IITF) facilities were used as well as an older green roof located in the University of Puerto Rico. The IITF green roofs possessed the...

Advances in genomic science have enabled comparative approaches that can evaluate the evolution of genes and mechanisms underlying phenotypic traits relevant to angiosperm forest trees. Wood formation is an excellent subject for comparative genomics, as it is an ancestral trait for angiosperms and has undergone significant modification in different angiosperm lineages. This chapter discusses some of the traits associated with wood formation, what is currently known about the genes and mechanisms regulating these traits, and how comparative evolutionary genomic studies can be undertaken to...