Thomas H. Whitlow

Bio: Thomas H. Whitlow is an academic researcher from Cornell University. The author has contributed to research in topics: Stormwater & Ash yellows. The author has an hindex of 22, co-authored 59 publications receiving 2225 citations.

Coupling biogeochemical cycles in urban environments: ecosystem services, green solutions, and misconceptions

Abstract: Urban green space is purported to offset greenhouse-gas (GHG) emissions, remove air and water pollutants, cool local climate, and improve public health. To use these services, municipalities have focused efforts on designing and implementing ecosystem-services-based “green infrastructure” in urban environments. In some cases the environmental benefits of this infrastructure have been well documented, but they are often unclear, unquantified, and/or outweighed by potential costs. Quantifying biogeochemical processes in urban green infrastructure can improve our understanding of urban ecosystem services and disservices (negative or unintended consequences) resulting from designed urban green spaces. Here we propose a framework to integrate biogeochemical processes into designing, implementing, and evaluating the net effectiveness of green infrastructure, and provide examples for GHG mitigation, stormwater runoff mitigation, and improvements in air quality and health.

An Improved Method for Using Electrolyte Leakage to Assess Membrane Competence in Plant Tissues

Abstract: A new expression for ion leakage from plant tissue, the tissue ionic conductance (gTi), is compared with electrical conductivity (EC) and a commonly used damage index (Id) to test the ability of each expression to correctly describe leakiness in two model systems representing examples of physiological processes with well-known effects on membrane permeability. In experiments in which drought-acclimated leaves were compared with nonacclimated leaves and senescing leaves were compared with nonsenescing leaves, Id contradicted our expectation that acclimated tissue would be less leaky than nonacclimated tissue, and gTi and EC confirmed this expectation. In a comparison of senescing and nonsenescing tissue, Id again contradicted our expectation that senescing tissue would be more leaky than nonsenescing, and EC and gTi were confirming. Using a diffusion analysis approach, we show that Id fails to account for variation in the concentration gradient between the tissue and the bathing solution and variation in the surface area through which efflux occurs. Furthermore, because Id is a parameter that relates treatment performance to control performance as a percentage value, it distorts the actual differences among treatments. The resulting artifacts lead to a presentation of membrane integrity which is probably incorrect. EC is a more direct measurement of net ion efflux and appears to be less vulnerable to artifact. However, because gTi is the only expression that explicitly includes chemical driving force and tissue surface area, it is the most reliable of the three expressions.

Osmotic Adjustment and Solute Constituents in Leaves and Roots of Water-stressed Cherry (Prunus) Trees

Abstract: Tissue osmotic potential and solute constituents were evaluated in leaves and roots of well-watered and water-stressed Prunus avium L. × pseudocerasus Lindl. 'Colt' and Prunus cerasus L. 'Meteor'. Osmotic potential at full turgor decreased in response to water stress for leaves and roots of both cultivars. For 'Colt', a cultivar with an indeterminate growth habit, decreased by 0.56 MPa and 0.38 MPa for terminal expanding leaves and older expanded leaves, respectively. For 'Meteor', a cultivar with a determinate growth habit, decreased by ≈0.47 MPa in both terminal and older leaves. Root was alike for both cultivars and showed a similar decrease of 0.20 MPa in response to water stress. Roots had considerably higher than did leaves in both cultivars, irrespective of irrigation treatment. Soluble carbohydrates and potassium (K + ) were the major solute constituents in both cultivars. Of the soluble carbohydrates, sorbitol was found in the greatest concentration and accounted for the bulk of water stress-induced solute accumulation in both cultivars. Regardless of the irrigation treatment, mature leaves of 'Meteor' consistently had lower (typically 0.4 MPa) than 'Colt'. This variation in between Prunus cultivars suggests the potential for selection of cultivars with low and possibly superior drought resistance.

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Reducing redundancy in invasion ecology by integrating hypotheses into a single theoretical framework

Abstract: Aim Invasion ecology includes many hypotheses Empirical evidence suggests that most of these can explain the success of some invaders to some degree in some circumstances If they all are correct, what does this tell us about invasion? We illustrate the major themes in invasion ecology, and provide an overarching framework that helps organize research and foster links among subfields of invasion ecology and ecology more generally Location Global Methods We review and synthesize 29 leading hypotheses in plant invasion ecology Structured around propagule pressure (P), abiotic characteristics (A) and biotic characteristics (B), with the additional influence of humans (H) on P, A and B (hereon PAB), we show how these hypotheses fit into one paradigm P is based on the size and frequency of introductions, A incorporates ecosystem invasibility based on physical conditions, and B includes the characteristics of invading species (invasiveness), the recipient community and their interactions Having justified the PAB framework, we propose a way in which invasion research could progress Results By highlighting the common ground among hypotheses, we show that invasion ecology is encumbered by theoretical redundancy that can be removed through integration Using both holistic and incremental approaches, we show how the PAB framework can guide research and quantify the relative importance of different invasion mechanisms Main conclusions If the prime aim is to identify the main cause of invasion success, we contend that a top-down approach that focuses on PAB maximizes research efficiency This approach identifies the most influential factors first, and subsequently narrows the number of potential causal mechanisms By viewing invasion as a multifaceted process that can be partitioned into major drivers and broken down into a series of sequential steps, invasion theory can be rigorously tested, understanding improved and effective weed management techniques identified