In the transition zone between aquifers and basal aquitards, the perchloroethenepools are more recalcitrant than those elsewhere in the aquifer. The aim of this study is to demonstrate that the transition zone is an ecotone where the biodegradation of chloroethenes from aged-pools of perchloroethene is favored. A field site was selected where an aged pool exists at the bottom of a transition zo...

The desert-oasis ecotone, as a crucial natural barrier, maintains the stability of oasis agricultural production and protects habitat security. This paper investigates dynamic evolution ecotone in Tarim River Basin predicts near-future land-use change using cellular automata–Markov (CA-Markov) model. Results indicate that overall area shows shrinking trend (from 67,642 km2 1990 to 46,613 2015) ...

1. Many studies in northern Europe, North and South America, describe regional trends of population densification at altitudinal and polar tree lines during the 20th century. The purpose of this study was (1) to ascertain if this regeneration enhancement is present across the alpine ecotones of the Pyrenees, (2) if synchronous recruitment trends are common among the studied populations and (3) ...

It has been shown that height measurements obtained by airborne laser scanning (ALS) with high point density (>7–8 m ́2) can be used to detect small trees in the alpine tree line—an ecotone sensitive to climate change. Because the height measurements do not discriminate between trees and other convex structures with positive height values, this study aimed at assessing the contribution of ALS ba...

Detecting latitudinal range shifts of forest trees in response to recent climate change is difficult because of slow demographic rates and limited dispersal but may be facilitated by spatially compressed climatic zones along elevation gradients in montane environments. We resurveyed forest plots established in 1964 along elevation transects in the Green Mountains (Vermont) to examine whether a ...

Cockatoo grass [Alloteropsis semialata (R.Br.) A. Hitchc.] is considered a keystone species in northern Australian ecosystems as it provides a food resource for many species, including several endangered vertebrates. This study examined both local and regional environmental factors influencing cockatoo grass distribution and abundance in the Wet Tropics of north Queensland, Australia. Local dis...

Sea level rise and the associated inland shift of the marsh-mangrove ecotone in south Florida have raised many scientific and management concerns in recent years. Holocene paleoecological records can provide an important baseline to shed light on the long-term dynamics of vegetation changes across this ecotone in the past, which is needed to predict the future. In this study, we present palynol...

Anthony A. Leiserowitz, Robert W. Kates, and Thomas M. Parris 1Decision Research, Eugene, Oregon 97401; Environmental Studies, University of Oregon; Center for Research on Environmental Decisions, Columbia University; email: [email protected] 2Independent scholar, Trenton, Maine 04605; Initiative on Science and Technology for Sustainability; email: [email protected] 3Sustainability Programs, ...