NSF-IOS-BSF: When physiology meets landscape ecology: Effects of landscape fragmentation on physiological tradeoffs

University Of Arizona, Tucson AZ

Investigators

Abstract

Agricultural activity can result in the fragmentation of natural habitats, which can lead to loss of total habitat area, reduced average habitat patch size, and increased distances among patches. All these may lead to the decline and extinction of local populations that live in these fragmented habitats. Organisms in general have finite amounts of resources (nutritional energy) to invest in growth, maintenance, dispersal and reproduction. Allocation of resources to any one of these functions reduces the amount available to the others. This study will test the hypothesis that a tradeoff in the amount of resources allocated to dispersal versus resources allocated to reproduction serves as the physiological mechanistic link by which organisms translate environmental variability experienced in fragmented habitats into population persistence within those habitats. This study will test this hypothesis using a fast-moving ground-dwelling beetle in the fragmented habitat of the Southern Judean Lowlands in Israel. Through the outreach program Insect Discovery, about 10,000 2nd grade students in Tucson, AZ will use insects to learn biological principles in specially designed workshops and classroom visits. In addition, 66 undergraduate preceptors and 12 graduate students will be trained in science outreach and how to convey an enthusiasm for science to the general public. Habitat fragmentation is a dominant feature of landscapes particularly where intensive cultivation results in increased fragmentation of natural habitats. A novel, integrative conceptual framework is proposed in which spatial characteristics of the environment, imposed by fragmentation, lead to specific life-history traits that increase individual survival and decrease the likelihood of population extinction. As habitat fragmentation increases, organisms should invest more into dispersal and less into reproduction, resulting in a resource allocation tradeoff between reproduction and dispersal along a habitat fragmentation gradient. Emerging from this are three explicit and testable hypotheses that predict that the dispersal-reproduction tradeoff is the mechanistic link by which organisms translate environmental variation created by habitat fragmentation into variation in species abundances that lower local extinction probability and increase population persistence. These hypotheses will be tested in a well-studied fragmented landscape in the Southern Judea Lowlands of Israel, focusing on a fast-moving, ground-dwelling beetle. This study brings together techniques from landscape ecology and ecological physiology across multiple scales, from the individual, to patches, to populations, to whole landscapes. This project will support Insect Discovery, an outreach program that uses insects to teach biological principles to nearly 10,000 2nd grade students in Tucson, AZ, most of whom are economically disadvantaged, underserved minorities. In addition, 66 undergraduate preceptors and 12 graduate students will be trained in science outreach and how to convey an enthusiasm for science to the general public.