Peter R. Long

Sensitivity of global terrestrial ecosystems to climate variability

The identification of properties that contribute to the persistence and resilience of ecosystems despite climate change constitutes a research priority of global relevance. Here we present a novel, empirical approach to assess the relative sensitivity of ecosystems to climate variability, one property of resilience that builds on theoretical modelling work recognizing that systems closer to critical thresholds respond more sensitively to external perturbations. We develop a new metric, the vegetation sensitivity index, that identifies areas sensitive to climate variability over the past 14 years. The metric uses time series data derived from the moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index, and three climatic variables that drive vegetation productivity (air temperature, water availability and cloud cover). Underlying the analysis is an autoregressive modelling approach used to identify climate drivers of vegetation productivity on monthly timescales, in addition to regions with memory effects and reduced response rates to external forcing. We find ecologically sensitive regions with amplified responses to climate variability in the Arctic tundra, parts of the boreal forest belt, the tropical rainforest, alpine regions worldwide, steppe and prairie regions of central Asia and North and South America, the Caatinga deciduous forest in eastern South America, and eastern areas of Australia. Our study provides a quantitative methodology for assessing the relative response rate of ecosystems—be they natural or with a strong anthropogenic signature—to environmental variability, which is the first step towards addressing why some regions appear to be more sensitive than others, and what impact this has on the resilience of ecosystem service provision and human well-being.

Distribution, habitat and status of 'Endangered' Sakalava Rail of Madagascar.

Summary The ‘Endangered’ Sakalava Rail Amaurornis olivieri is endemic to wetlands in western Madagascar, where it has been recorded between the Betsiboka river in the north and the Mangoky river in the south. Between August 2003 and November 2006, including dry and wet seasons, we surveyed 36 potentially suitable wetlands throughout its known range. We found Sakalava Rails at five sites: Lacs Kinkony, Ampandra, Amparihy, Sahapy and Mandrozo. At each site the population was small (12–39 individuals) and the highest density was 20 individuals km 2 . We found up to 67 birds in each field visit and the total number of birds (sum of maxima at each site) seen was 100. We estimate the total population at the five sites to be 215 rails. We cannot confirm that the population lies within the range estimated in the current Red List (250–999 individuals), although this may yet be proven correct. The typical breeding habitat of Sakalava Rail is lotic marshes with a mixture of large areas of open water, reed Phragmites mauritianus and floating Salvinia hastata. The major threats to Sakalava Rail appear to be habitat loss caused by wetland conversion to rice fields and by fires, disturbance by fishermen and people from local villages, and hunting. Other processes that may alter the ecological character of wetlands and so affect their suitability for Sakalava Rails, such as hydrological change or the effects of exotic fish or vegetation, remain to be investigated.

Remote assessment of locally important ecological features across landscapes: how representative of reality?

The local ecological footprinting tool (LEFT) uses globally available databases, modeling, and algorithms to, remotely assess locally important ecological features across landscapes based on five criteria: biodiversity (beta-diversity), vulnerability (threatened species), fragmentation, connectivity, and resilience. This approach can be applied to terrestrial landscapes at a 300-m resolution within a given target area. Input is minimal (latitude and longitude) and output is a computer-generated report and series of maps that both individually and synthetically depict the relative value of each ecological criteria. A key question for any such tool, however, is how representative is the remotely obtained output compared to what is on the ground. Here, we present the results from comparing remotely- vs. field-generated outputs from the LEFT tool on two distinct study areas for beta-diversity and distribution of threatened species (vulnerability), the two fields computed by LEFT for which such an approach is feasible. The comparison method consists of a multivariate measure of similarity between two fields based on discrete wavelet transforms, and reveals consistent agreement across a wide range of spatial scales. These results suggest that remote assessment tools such as LEFT hold great potential for determining key ecological features across landscapes and for being utilized in preplanning biodiversity assessment tools.

LEFT – a web-based tool for the remote measurement and estimation of ecological value across global landscapes

Summary 1.The overall aim in the development of the Local Ecological Footprinting tool (LEFT) was to design a web-based tool that could provide quickly obtained quantitative data to assist landowners when making land-use change decisions and to help them minimise the environmental impact and determine areas of greatest ecological risk in their operations. 2.LEFT works for almost any region in the world and uses freely available satellite imagery, biotic and abiotic data from existing global databases, models and algorithms to deliver a customised report for a selected area within one hour of job submission. 3.Biotic data automatically obtained for a selected landscape includes terrestrial vertebrate and plant species occurrence data, information on their conservation status and remotely sensed vegetation productivity. Abiotic information obtained includes temperature, precipitation, water availability, insolation, topography, elevation, distribution of urban infrastructure, and location of wetlands. 4.The tool performs a number of analyses on the biotic and abiotic data to produce maps for the selected area at a 30m resolution depicting land cover type, numbers of globally threatened terrestrial vertebrate and plant species, beta-diversity of terrestrial vertebrates and plants, habitat intactness, wetland habitat connectivity, numbers of migratory species and vegetation resilience. Results are also aggregated to produce a summary map demonstrating areas of high and low ecological value across the selected area. 5.LEFT has been designed to be intuitive to use, requiring no specialised software or user expertise. Input is extremely easy and requires the user to highlight the area of interest on a map or using grid co-ordinates. Output is delivered via the web application and comprises a customised PDF containing the maps and a zip file of GIS data for the area requested. Users may run an unlimited number of LEFT analyses and download reports free of charge. In addition to the free tool described in this paper, there is also a paid service: individual LEFT analyses can be upgraded for a charge to allow access to the geographically subsetted datasets generated for each report. This data is supplied as a zip file containing raster datasets for the layers in the LEFT analysis in GeoTIFF format. These can be opened and queried in a Geographical Information System (GIS) software package. This article is protected by copyright. All rights reserved.

DATASET - Predicting bird phenology from space

Great tit and blue tit breeding data and habitat data was collected in the field. The MOD09Q1 and MYD09Q1 data products used to calculate EVI are courtesy of the online Data Pool at the NASA Land Processes Distributed Active Archive Center (LP DAAC), USGS/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota. Cloudiness data is based on the same MODIS sensors as in the case of EVI data, this time using the MOD08 product (collection 5.1, accessed through Level 1 and Atmosphere Archive and Distribution System – LAADS, ladsweb.nascom.nasa.gov).