Figure 8 - uploaded by Russell Milne
Content may be subject to copyright.
State reached by an overfished, macroalgae-dominated system after temporary subsidies to ecotourism. The four states shown differ in their transient and steady-state behaviour.
Source publication
Overfishing has the potential to severely disrupt coral reef ecosystems worldwide, while harvesting at more sustainable levels instead can boost fish yield without damaging reefs. The dispersal abilities of reef species mean that coral reefs form highly connected environments, and the viability of reef fish populations depends on spatially explicit...
Contexts in source publication
Context 1
... our simulations involving short-term subsidization of the tourism sector in a heavily over-fished system, we found that depending on how much tourism was subsidized and for how long, four different outcomes were possible (Fig. 8). In increasing order of subsidy length or amount, these were the status quo (macroalgae dominance), a temporary recovery of the herbivorous fish population, a temporary recovery of both fish and coral, and a permanent shift to a tourism-based economy with healthy fish and coral populations. When fish and/or coral recovered, temporarily ...
Context 2
... is not conservationdependent. This is achievable for harvesting rates between 20 and 30 percent per year, similar to 440 what has been seen in a previous model [Thampi et al., 2018]. Secondly, we found that promoting ecotourism can shift a system back to a coral-dominated state over an appreciable timeframe, even if such promotion is temporary (Fig. 8) or spatially limited in scope (Fig. 7). These additional options allow coral reef managers more choice in the strategies they have for reef ...
Context 3
... systems, and our results on reef recovery via economic transitions indicate that variation in c z can have a significant environmental impact. This opens the door for future research on how changing economic conditions could lead to more or less fragmented reefs (and hence alter species composition). Based 490 on our results (see for instance Figs. 2 and 8), we predict that positive values for c z would boost coral growth, while negative values could increase fish populations or lead to macroalgae dominance, depending on the underlying biological conditions. (Hence, having a variety of local-scale values for c z could provide another way to generate a fragmented system.) Since the ...
Citations
... Decreasing the net mitigation cost often has a beneficial effect on the environment, by increasing the proportion of mitigators and moving the system away from less stable oscillations, as seen in forest cover and coral reef models [60,63,80,99]. However, in a forest cover model, initial conditions with low mitigator frequency led to oscillations in opinion and forest cover before the system reached a stable state, as the cost of mitigation was increased [80]. ...
Humans and the environment form a single complex system where humans not only influence ecosystems but also react to them. Despite this, there are far fewer coupled human–environment system (CHES) mathematical models than models of uncoupled ecosystems. We argue that these coupled models are essential to understand the impacts of social interventions and their potential to avoid catastrophic environmental events and support sustainable trajectories on multi-decadal timescales. A brief history of CHES modelling is presented, followed by a review spanning recent CHES models of systems including forests and land use, coral reefs and fishing and climate change mitigation. The ability of CHES modelling to capture dynamic two-way feedback confers advantages, such as the ability to represent ecosystem dynamics more realistically at longer timescales, and allowing insights that cannot be generated using ecological models. We discuss examples of such key insights from recent research. However, this strength brings with it challenges of model complexity and tractability, and the need for appropriate data to parameterize and validate CHES models. Finally, we suggest opportunities for CHES models to improve human–environment sustainability in future research spanning topics such as natural disturbances, social structure, social media data, model discovery and early warning signals.
This article is part of the theme issue ‘Ecological complexity and the biosphere: the next 30 years’.
... Overfished marine fisheries can become resource-depleted and lose their profitability within a short period of time, despite their initial success. In a few studies, overfishing has been investigated [77]. The fishing industry also poses indirect risks. ...
In Pakistan, the fisheries sector is capable of making a significant contribution to the national economy. However, the proper and sustainable development of this sector is essential to its success, and we need to be aware of all the risks that it faces. At present, there is a dearth of comprehensive research that details, compares, and proposes applied measures to mitigate the risks facing the fisheries sector. Thus, this study is the first novel attempt to fill this gap. The data were collected through a survey and analyzed by multi-criteria decision analysis (MCDA). The study postulates that Sindh fisheries are affected by five main risk factors, namely technical, market, ecological, natural, and management. These risk factors are arranged from least to most significant. With regard to the performances of the main risk factors, management risk was ranked as the greatest risk, followed by ecological risk, natural risk, and technical risk. The findings of this study provide a road map for managerial decisions. Furthermore, this study also presents some potential limitations related to the scale of the data and analysis methods. Future studies may therefore use data collected on a large scale and alternative quantitative approaches.
