Characterising landscape connectivity for conservation planning using a dispersal guild approach

Context Land use changes have modified the extent and structure of native vegetation, resulting in fragmentation of native species habitat. Connectivity is increasingly seen as a requirement for effective conservation in these landscapes, but the question remains: ‘connectivity for which species?’. Objective The aim of this study was to develop and then apply a rapid, expert-based, dispersal guild approach where species are grouped on similar fine-scale dispersal behaviour (such as between scattered trees) and habitat characteristics. Methods Dispersal guilds were identified using clustering techniques to compare dispersal and habitat parameters elicited from experts. We modelled least-cost paths and corridors between patches and individual movement probabilities within these corridors for each of the dispersal guilds using Circuitscape. We demonstrate our approach with a case study in the Tasmanian Northern Midlands, Australia. Results The dispersal guild approach grouped the 12 species into five dispersal guilds. The connectivity modelling of those five guilds found that broadly dispersing species in this landscape, such as medium-sized carnivorous mammals, were unaffected by fragmentation while from the perspective of the three dispersal guilds made up of smaller mammals, the landscape appeared highly fragmented. Conclusions Our approach yields biologically defensible outputs that are broadly applicable, particularly for conservation planning where data and resources are limited. It is a useful first step in multi-species conservation planning which aims to identify those species most in need of conservation efforts

Using dispersal guilds to assess connectivity at the landscape scale: a case study in the Tasmanian Midlands

The objective of this study is to explore the potential for using dispersal guilds with connectivity modelling to characterise landscape connectivity for conservation planning. By using dispersal guilds as the focal conservation target, we can capture a range of responses to fragmentation without having to resort to time‐consuming single species modelling. This approach can identify those groups of species that are most impacted by fragmentation and are likely to benefit most from restoring links within a landscape. As well as developing the dispersal guild concept, we describe a process for engaging experts in eliciting the ecological and dispersal characteristics of target species, and identifying dispersal groups through cluster analysis of these characteristics. We used a case study in the Our study area the Northern Midlands of Tasmania to illustrate this approach

Ice in the 1994 Rabaul eruption cloud: implications for volcano hazard and atmospheric effects

VOLCANIC clouds are an important natural hazard to aircraft1, and host chemical reactions that interest both volcanologists2,3 and atmospheric scientists4-6. Ice has been suggested as a possible component of eruption clouds7, but there has been no direct evidence for its presence. Here we report the detection, using a satellite-borne infrared sensor, of ≳ 2 million tonnes of ice in the cloud produced by the September 1994 eruption of Rabaul volcano, in Papua New Guinea. The cloud also contained relatively low levels of sulphur dioxide (80 ± 50 kilotonnes), compared with other stratospheric eruption clouds. The unusual aspects of this cloud may be related to the entry of sea water into the volcanic vent, and its participation in the eruption column. Past eruptions that occurred in similar (coastal) settings, such as those of Krakatau and Santorini, might have had less effect on the atmosphere than their volume alone would suggest, because the presence of ice may decrease the residence time of ash and sulphur in the atmosphere. In addition, the ability of ice to mask the characteristic spectral signature of volcanic ash will increase the difficulty of designing airborne ash detection systems for aviation safety