Building bridges in development: Five recommendations to connect the islands of research, policy and practice.

Elizabeth Harrison, Eleanor Jew, Thomas Smith, Iqbal Ahmed and Sarah Peck present the recommendations from a recent conference for early-career researchers on bridging the gap in development research, policy and practice. Participants were encouraged to consider partnership-based solutions to development problems. From having a realistic understanding of intended outcomes to formulating relevant research questions, constructive debate took place on how best to navigate and undertake practical solutions to developing dialogue across sectors

Exploring temporality in socio-ecological resilience through experiences of the 2015–16 El Niño across the Tropics

In a context of both long-term climatic changes and short-term climatic shocks, temporal dynamics profoundly influence ecosystems and societies. In low income contexts in the Tropics, where both exposure and vulnerability to climatic fluctuations is high, the frequency, duration, and trends in these fluctuations are important determinants of socio-ecological resilience. In this paper, the dynamics of six diverse socio-ecological systems (SES) across the Tropics – ranging from agricultural and horticultural systems in Africa and Oceania to managed forests in South East Asia and coastal systems in South America – are examined in relation to the 2015–16 El Niño, and the longer context of climatic variability in which this short-term ‘event’ occurred. In each case, details of the socio-ecological characteristics of the systems and the climate phenomena experienced during the El Niño event are described and reflections on the observed impacts of, and responses to it are presented. Drawing on these cases, we argue that SES resilience (or lack of) is, in part, a product of both long-term historical trends, as well as short-term shocks within this history. Political and economic lock-ins and dependencies, and the memory and social learning that originates from past experience, all contribute to contemporary system resilience. We propose that the experiences of climate shocks can provide a window of insight into future ecosystem responses and, when combined with historical perspectives and learning from multiple contexts and cases, can be an important foundation for efforts to build appropriate long-term resilience strategies to mediate impacts of changing and uncertain climates

Miombo woodland under threat : Consequences for tree diversity and carbon storage

Agriculture is expanding rapidly in the miombo woodlands of sub-Saharan Africa. Clear felling results in the loss of species and ecosystem services. The remaining woodland is used as a vital support system for the farming communities, and the impact of this utilisation on biodiversity and ecosystem service provision is not clear. Understanding these effects will aid the development of effective, sustainable land management strategies for multiple outcomes, including biodiversity conservation and resource utilisation. This study provides new data on miombo woodland tree species diversity, structure and carbon storage from a 8766km2 landscape in south-western Tanzania, which is undergoing rapid conversion to tobacco cultivation.Human utilisation of the woodland was classified by ground surveys which recorded evidence of use (e.g. cut poles and timber, removal of bark and roots, access routes). Nine sites were surveyed and categorised into three groups: high, medium and low utilisation. To determine the effect of utilisation on the tree community stem density, diameter at breast height, tree species richness and carbon storage were recorded. In the low utilisation sites carbon storage was similar to that found in other miombo woodlands (28tHa-1), and the Shannon Wiener diversity score for tree species diversity was 3.44. However, in the high utilisation sites, tree species diversity (2.86) and carbon storage declined (14.6tHa-1). In areas of moderate utilisation diversity and carbon storage were maintained, but the structure of the woodland was affected, with a reduction of Class 1 (Diameter at Breast Height (DBH)<10cm) stems, demonstrating low recruitment which leads to a reduction in sustainability. Tree species richness and abundance demonstrated an intermediate disturbance effect in relation to utilisation, with highest levels at medium utilisation sites.Key miombo woodland species from the subfamily Caesalpinioideae in the two genera Brachystegia and Julbernardia were present in all sites, but the frequency of Brachystegia species declined by 60% from low to high utilisation. The IUCN near-threatened timber species Pterocarpus angolensis, highly protected in Tanzania, was harvested throughout the study site, and the majority of trees recorded were immature (DBH. ≤. 20. cm), suggesting that it is commercially extinct for the foreseeable future.These findings illustrate that in miombo woodlands with low to medium utilisation levels key miombo species are retained, and tree species diversity and carbon storage remains optimal. Sustainable land management plans need to regulate utilisation within miombo landscapes and retain areas of woodland. This will ensure their long term viability, and continue to support the 100. million people who are reliant on miombo woodlands for their goods and services

Small-scale studies of roasted ore waste reveal extreme ranges of stable mercury isotope signatures

Active and closed Hg mines are significant sources of Hg contamination to the environment, mainly due to large volumes of mine waste material disposed of on-site. The application of Hg isotopes as source tracer from such contaminated sites requires knowledge of the Hg isotope signatures of different materials potentially released to the environment. Previous work has shown that calcine, the waste residue of the on-site ore roasting process, can exhibit distinct Hg isotope signatures compared with the primary ore. Here, we report results from a detailed small-scale study of Hg isotope variations in calcine collected from the closed New Idria Hg mine, San Benito County, CA, USA. The calcine samples exhibited different internal layering features which were investigated using optical microscopy, micro X-ray fluorescence, micro X-ray absorption spectroscopy (mu-XAS), and stable Hg isotope analysis. Significant Fe, S, and Hg concentration gradients were found across the different internal layers. Isotopic analyses revealed an extreme variation with pronounced isotopic gradients across the internal layered features. Overall, delta Hg-202(+/- 0.10 parts per thousand, 2 SD) describing mass-dependent fractionation (MDF) ranged from -5.96 to 14.49 parts per thousand, which is by far the largest range of delta Hg-202 values reported for any environmental sample. In addition, Delta Hg-199 (+/- 0.06 parts per thousand, 2 SD) describing mass-independent fractionation (MIF) ranged from -0.17 to 0.21 parts per thousand. The mu-XAS analyses suggested that cinnabar and metacinnabar are the dominant Hg-bearing phases in the calcine. Our results demonstrate that the incomplete roasting of HgS ores in Hg mines can cause extreme mass-dependent Hg isotope fractionations at the scale of individual calcine pieces with enrichments in both light and heavy Hg isotopes relative to the primary ore signatures. This finding has important implications for the application of Hg isotopes as potential source tracers for Hg released to the environment from closed Hg mines and highlights the need for detailed source signature identification. (C) 2014 Elsevier Ltd. All rights reserved

Stable Hg Isotope Signatures in Creek Sediments Impacted by a Former Hg Mine

The goal of this study was to investigate the Hg stable isotope signatures of sediments in San Carlos Creek downstream of the former Hg mine New Idria, CA, USA and to relate the results to previously studied Hg isotope signatures of unroasted ore waste and calcine materials in the mining area. New Idria unroasted ore waste was reported to have a narrow δ²⁰²Hg range (−0.09 to 0.16‰), while roasted calcine materials exhibited a very large variability in δ²⁰²Hg (−5.96 to 14.5‰). In this study, creek sediment samples were collected in the stream bed from two depths (0–10 and 10–20 cm) at 10 locations between the mine adit and 28 km downstream. The sediment samples were size-fractionated into sand, silt, and (if possible) clay fractions as well as hand-picked calcine pebbles. The sediment samples contained highly elevated Hg concentrations (8.2 to 647 μg g^–1) and displayed relatively narrow mass-dependent fractionation (MDF, δ²⁰²Hg; ± 0.08‰, 2SD) ranges (−0.58 to 0.24‰) and little to no mass-independent fractionation (MIF, Δ¹⁹⁹Hg; ± 0.04‰, 2SD) (0.00 to 0.10‰), similar to what was observed previously for the unroasted ore waste. However, due to the highly variable and overlapping δ²⁰²Hg signatures of the calcines, they could not be ruled out as source of Hg to the creek sediments. Overall, our results suggest that analyzing creek sediments downstream of former Hg mines can provide a more reliable Hg isotope source signature for tracing studies at larger spatial scales, than analyzing the isotopically highly heterogeneous tailing piles typically found at former mining sites. Creek sediments carry an integrated isotope signature of Hg transported away from the mine with runoff into the creek, eventually affecting ecosystems downstream