1,721,177 research outputs found
Social-ecological tipping points in world deltas: designing a safe and just operating space for the Chilika lagoon fishery, India
No full textof feedbacks, delays and cross-scale interactions can undergo surprising dynamics. Climate change and globalisation are magnifying social-ecological complexities across regional systems, questioning policies that prioritise stability over variability, predictability over adaptability, and optimisation over persistence. Similar concerns extend to modelling techniques that explore a limited number of scenarios framed by stationary external conditions and an absence of human-natural feedbacks. Such methods are ill-equipped to identify safe and just operating spaces for sustainable development, characterised by interacting environmental limits, tipping points and regime shifts. To this end, this study develops and evaluates a system dynamics model to identify the safe and just operating spaces of a natural resource system with a legacy of collapse. Based on the Chilika lagoon fishery of the Mahanadi delta, India, the model explores how decision-makers can influence internal resilience to a spectrum of plausible driver trajectories and interactions.The principal contribution of this study is the operationalisation of the safe and just spaces concept as a forward-looking tool to identify interacting pathways to sustainable futures. Specific to Chilika, periodically dredging the tidal outlet desensitises the fishery to the hydroclimatic processes causing collapse under do nothing governance. However, stable resource availability facilitates fishing effort growth that can trigger overexploitation by 2050. Amongst a suite of social-ecological trade-offs, fishing bans and alternative livelihoods widen the safe spaces but require decision-makers to forgo Chilika’s common-pool status. Normative safe spaces are found to have properties of social-ecological resilience, including latitude, resistance and precariousness. These characteristics help identify “core” safe and just spaces, representing interacting trajectories with the highest chances of reaching the sustainable future. Contrastingly, futures of fishery overcapacity and livelihood loss associate with deeply undesirable dynamics, including ecological surprise, tipping points and hysteresis. This study is transferable to social-ecological system of stocks and flows, feedbacks and future uncertainty, highlighting considerations for how we view sustainability and shape regional systems to avoid boundaries of safe and just spaces
Modelling future safe and just operating spaces in regional social-ecological systems
Full text linkShaping social-ecological systems towards sustainable, desirable and equitable futures is often hampered by complex human-natural feedbacks, emergence and nonlinearities. Consequently, the future of systems vulnerable to collapse is uncertain under plausible trajectories of environmental change, socioeconomic development and decision-making. We develop a modelling approach that incorporates driver interactions and feedbacks to operationalise future “safe and just operating spaces” for sustainable development. Monte Carlo simulations of fish catch from India’s Chilika lagoon are compared to conditions that are ecologically and socioeconomically desirable as per today’s norms. Akin to a satellite-navigation system, the model identifies pathways giving at least a 75% chance of achieving the desirable future, while simultaneously diverting the system away from undesirable pathways. Critically for regional governance, the driver limits and trade-offs associated with regulating the resource are realised. More widely, this approach represents a adaptable framework that explores the resilience of social-ecological interactions and feedbacks underpinning regional sustainable development
Ecological doom-loops: why ecosystem collapses may occur much sooner than expected – new research
No full textRegime shifts occur disproportionately faster in larger ecosystems
Full text linkRegime shifts can abruptly affect hydrological, climatic and terrestrial systems, leading to degraded ecosystems and impoverished societies. While the frequency of regime shifts is predicted to increase, the fundamental relationships between the spatial-temporal scales of shifts and their underlying mechanisms are poorly understood. Here we analyse empirical data from terrestrial (n=4), marine (n=25) and freshwater (n=13) environments and show positive sub-linear empirical relationships between the size and shift duration of systems. Each additional unit area of an ecosystem provides an increasingly smaller unit of time taken for that system to collapse, meaning that large systems tend to shift more slowly than small systems but disproportionately faster. We substantiate these findings with five computational models that reveal the importance of system structure in controlling shift duration. The findings imply that shifts in Earth ecosystems occur over ‘human’ timescales of years and decades, meaning the collapse of large vulnerable ecosystems, such as the Amazon rainforest and Caribbean coral reefs, may take only a few decades once triggered
Models simulating abrupt changes in the Chilika lagoon fishery, the Easter Island community, forest dieback and lake water quality
No full textThis deposit is in support of Willcock et al "Anthropocene ecosystems collapse sooner with faster, multiple and noisy drivers". It covers the following items: (i) A list of the files contained within this data deposit; (ii) How to access and download the specialist software required to view and simulate the system dynamics models (STELLA ‘isee Player’); (iii) How to run isee Player to simulate the models; (iv) How to access and download the standard statistical software ‘R’ to run the R scripts; (v) How to load ‘R’ and modify the standard R script to analyse a subset of the model runs. This file will also details the ‘required content’ (e.g. software versions), as specified in the ‘nr-software-policy.pdf’ document. The full descriptions of each of the four system dynamics models used in this manuscript can be read in the following papers: Lake Chilika – Cooper, G. S. &amp; Dearing, J. A. Modelling future safe and just operating spaces in regional social-ecological systems. Sci. Total Environ. 651, 2105–2117 (2019), https://doi.org/10.1016/j.scitotenv.2018.10.118 Easter Island – Brandt, G. &amp; Merico, A. The slow demise of Easter Island: Insights from a modeling investigation. Front. Ecol. Evol. 3, 13 (2015), https://www.frontiersin.org/article/10.3389/fevo.2015.00013 Lake phosphorus – Wang, R. et al. Flickering gives early warning signals of a critical transition to a eutrophic lake state. Nature 492, 419–22 (2012), http://dx.doi.org/10.1038/nature11655 TRIFFID - Ritchie, P. D. L., Clarke, J. J., Cox, P. M. &amp; Huntingford, C. Overshooting tipping point thresholds in a changing climate. Nat. 2021 5927855 592, 517–523 (2021), http://dx.doi.org/10.1038/nature11655</span
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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