Andy Hector

Bio: Andy Hector is an academic researcher from University of Oxford. The author has contributed to research in topics: Biodiversity & Species richness. The author has an hindex of 74, co-authored 183 publications receiving 36456 citations. Previous affiliations of Andy Hector include University of Zurich & Natural Environment Research Council.

Multifunctionality does not imply that all functions are positively correlated.

Abstract: The recent publication by Bradford et al. (1) argues that indices of ecosystem multifunctionality—the simultaneous performance of multiple ecosystem functions (2)—are only useful if all component functions “respond to community change in a positive correlated fashion.” We contend that this argument fundamentally misinterprets the concept of ecosystem multifunctionality.

The New Statistics with R: An Introduction for Biologists

Abstract: 1. Introduction 2. Comparing Groups: Analysis of Variance 3. Comparing Groups: Student's t test 4. Linear Regression 5. Comparisons using Estimates and Intervals 6. Interactions 7. Analysis of Covariance: ANCOVA 8. Maximum Likelihood and Generalized Linear Models 9. Generalized Linear Models for Data with Non-Normal Distributions 10. Mixed Effects Models 11. Generalized Linear Mixed-effects Models 12. Final Thoughts Appendix 1: A very short introduction to the R programming language for statistics and graphics

The influence of variable rainfall frequency on germination and early growth of shade-tolerant dipterocarp seedlings in borneo.

Abstract: Climate change induced alterations to rainfall patterns have the potential to affect the regeneration dynamics of plant species, especially in historically everwet tropical rainforest. Differential species response to infrequent rainfall may influence seed germination and seedling establishment in turn affecting species distributions. We tested the role of watering frequency intervals (from daily to six-day watering) on the germination and the early growth of Dipterocarpaceae seedlings in Borneo. We used seeds that ranged in size from 500 to 20,000 mg in order to test the role of seed mass in mediating the effects of infrequent watering. With frequent rainfall, germination and seedling development traits bore no relationship to seed mass, but all metrics of seedling growth increased with increasing seed mass. Cumulative germination declined by 39.4% on average for all species when plants were watered at six-day intervals, and days to germination increased by 76.5% on average for all species from daily to six-day intervals. Final height and biomass declined on average in the six-day interval by 16% and 30%, respectively, but the percentage decrease in final size was greater for large-seeded species. Rooting depth per leaf area also significantly declined with seed mass indicating large-seeded species allocate relatively more biomass for leaf production. This difference in allocation provided an establishment advantage to large-seeded species when water was non-limiting but inhibited their growth under infrequent rainfall. The observed reduction in the growth of large-seeded species under infrequent rainfall would likely restrict their establishment in drier microsites associated with coarse sandy soils and ridge tops. In total, these species differences in germination and initial seedling growth indicates a possible niche axis that may help explain both current species distributions and future responses to climate change.

The Role of Biodiversity

Abstract: Human activities have caused widespread loss of biodiversity raising concern about the potential impact on ecosystem processes (flows of energy and materials). A large body of recent research has shown that as species are lost from ecosystems there is, generally, a minor impact on ecosystem processes, but that this impact increases disproportionately as species diversity declines. Functional complementarity among species, due to variation in the ecological niches they occupy, appears to be the main mechanism driving this pattern. Species diversity is also usually positively related to ecosystem stability, i.e. their variation through time and the resistance and resilience to perturbation. These findings are already powerful arguments for the conservation of biodiversity, though current research aims to increase their relevance to the real world by including a more extensive range of ecosystems and processes, realistic food web structures, realistic (nonrandom) extinction scenarios and larger spatial scales. Keywords: ecosystem functioning; ecosystem stability; species diversity; conservation biology

Seeing the fruit for the trees in Borneo

Abstract: The recent mass fruiting of forest trees in Borneo is an urgent wakeup call: existing policy instruments, financial mechanisms, and forestry infrastructure are inadequate to take full advantage of these infrequent opportunities for forest restoration and conservation. Tropical forest restoration can provide substantial benefits for biodiversity conservation, climate change mitigation, and poverty alleviation. Yet the unpredictability of the synchronized flowering and consequent mass fruiting of many forest trees in Borneo presents a distinctive set of challenges for forest restoration. Significant financing and a considerable coordinated effort are required to prepare for future mass fruiting events if we are to capitalize on opportunities for ecological restoration. The continued high rate of forest clearance in this region and the rarity of mass fruiting events suggest that there may be few remaining opportunities to prevent widespread species extinctions. In this article we propose a facilitatory policy framework for forest restoration in Borneo to stimulate action in advance of the next mass fruiting of forest trees.

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

Human biochemical genetics

Abstract: So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

A safe operating space for humanity

Abstract: Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockstrom and colleagues.

Planetary boundaries: Guiding human development on a changing planet

Abstract: The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries—climate change and biosphere integrity—have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.

Effects of biodiversity on ecosystem functioning: a consensus of current knowledge

Abstract: Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth's biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services they provide to humanity. Ecological experiments, observations, and theoretical developments show that ecosystem properties depend greatly on biodiversity in terms of the functional characteristics of organisms present in the ecosystem and the distribution and abundance of those organisms over space and time. Species effects act in concert with the effects of climate, resource availability, and disturbance regimes in influencing ecosystem properties. Human activities can modify all of the above factors; here we focus on modification of these biotic controls. The scientific community has come to a broad consensus on many aspects of the re- lationship between biodiversity and ecosystem functioning, including many points relevant to management of ecosystems. Further progress will require integration of knowledge about biotic and abiotic controls on ecosystem properties, how ecological communities are struc- tured, and the forces driving species extinctions and invasions. To strengthen links to policy and management, we also need to integrate our ecological knowledge with understanding of the social and economic constraints of potential management practices. Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth's ecosystems and the diverse biota they contain.