Carrie V. Kappel

Coral reefs worldwide face unprecedented cumulative anthropogenic effects of interacting local human pressures, global climate change and distal social processes. Reefs are also bound by the natural biophysical environment within which they exist. In this context, a key challenge for effective management understands how anthropogenic and biophysical conditions interact with drive distinct coral reef configurations. Here, we use machine learning to conduct explanatory predictions on reef ecosystems defined by both fish and benthic communities. Drawing on the most spatially extensive dataset available across the Hawaiian archipelago—20 anthropogenic and biophysical predictors over 620 survey sites—we model the occurrence of four distinct reef regimes and provide a novel approach to quantify the relative influence of human and environmental variables in shaping reef ecosystems. Our findings highlight the nuances of what underpins different coral reef regimes, the overwhelming importanc...

Coral reefs worldwide face an uncertain future with many reefs reported to transition from being dominated by corals to macroalgae. However, given the complexity and diversity of the ecosystem, research on how regimes vary spatially and temporally is needed. Reef regimes are most often characterised by their benthic components; however, complex dynamics are associated with losses and gains in both fish and benthic assemblages. To capture this complexity, we synthesised 3,345 surveys from Hawai‘i to define reef regimes in terms of both fish and benthic assemblages. Model-based clustering revealed five distinct regimes that varied ecologically, and were spatially heterogeneous by island, depth and exposure. We identified a regime characteristic of a degraded state with low coral cover and fish biomass, one that had low coral but high fish biomass, as well as three other regimes that varied significantly in their ecology but were previously considered a single coral dominated regime. A...

As climatic changes and human uses intensify, resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points, or dramatic shifts in structure and function that are often costly and hard to reverse. Evidence indicates that explicitly addressing tipping points leads to improved management outcomes. Drawing on theory and examples from marine systems, we distill a set of seven principles to guide effective management in ecosystems with tipping points, derived from the best available science. These principles are based on observations that tipping points (1) are possible everywhere, (2) are associated with intense and/or multifaceted human use, (3) may be preceded by changes in early‐warning indicators, (4) may redistribute benefits among stakeholders, (5) affect the relative costs of action and inaction, (6) suggest biologically informed management targets, and (7) often require an adaptive response to monitoring. We suggest that ea...

A Marine Climate Impacts Workshop was held from 29 April to 3 May 2012 at the US National Center of Ecological Analysis and Synthesis in Santa Barbara. This workshop was the culmination of a series of six meetings over the past three years, which had brought together 25 experts in climate change ecology, analysis of large datasets, palaeontology, marine ecology and physical oceanography. Aims of these workshops were to produce a global synthesis of climate impacts on marine biota, to identify sensitive habitats and taxa, to inform the current Intergovernmental Panel on Climate Change (IPCC) process, and to strengthen research into ecological impacts of climate change.

Koedam and Dahdouh-Guebas raise the important issue that" there is a pressing need for in-depth investigation of the protection function of various mangrove formations and coastgeomorphological settings, various root types, and various species composition," and that" detangling the effect of such complexity under various

For too long, humanity's effects on the oceans have been out of sight and out of mind. Looking at the vast ocean from the shore or a jet's window, it is hard to imagine that this seemingly limitless area could be vulnerable to human activities. But during the past decade, reports have highlighted the consequences of human activity on our coasts and oceans, including collapsing fisheries, invasive species, unnatural warming and acidification, and ubiquitous ���dead zones��� induced by nutrient runoff. These changes have ...

ABSTRACT An important knowledge gap in ocean management is understanding quantitatively how ecosystem components respond to natural and anthropogenic stressors. A common assumption is that stressor-response relationships are linear. However, a growing body of literature demonstrates that many relationships are nonlinear, where small changes in a stressor prompt a disproportionately large ecological response. The goal of our work is to better understand the relationships between stressors and ecosystem properties and to identify where nonlinearities are likely to occur. To accomplish this we (1) conducted a wide literature search on single stressor-response relationships in pelagic ecosystems, (2) identified the degree of nonlinearity in these relationships using summary statistics from published regression models and models fit to available datasets, and (3) examined whether it is possible to glean general patterns in the shapes and strengths of the relationships and threshold responses across systems and stressors. Here, we present a characterization of stressor-response relationships in pelagic systems and address the potential risks associated with the simplifying assumption of linearity. In addition, we highlight important knowledge gaps that hinder our ability to gain insights into ecosystem thresholds and to help inform the selection of reference points for management to avoid tipping points in marine ecosystems.

Coral reefs worldwide face unprecedented cumulative anthropogenic effects of interacting local human pressures, global climate change and distal social processes. Reefs are also bound by the natural biophysical environment within which they exist. In this context, a key challenge for effective management is understanding how anthropogenic and biophysical conditions interact to drive distinct coral reef configurations. Here, we use machine learning to conduct explanatory predictions on reef ecosystems defined by both fish and benthic communities. Drawing on the most spatially extensive dataset available across the Hawaiian archipelago—20 anthropogenic and biophysical predictors over 620 survey sites—we model the occurrence of four distinct reef regimes and provide a novel approach to quantify the relative influence of human and environmental variables in shaping reef ecosystems. Our findings highlight the nuances of what underpins different coral reef regimes, the overwhelming import...

A major challenge for coral reef conservation and management is understanding how a wide range of interacting human and natural drivers cumulatively impact and shape these ecosystems. Despite the importance of understanding these interactions, a methodological framework to synthesize spatially explicit data of such drivers is lacking. To fill this gap, we established a transferable data synthesis methodology to integrate spatial data on environmental and anthropogenic drivers of coral reefs, and applied this methodology to a case study location-the Main Hawaiian Islands (MHI). Environmental drivers were derived from time series (2002-2013) of climatological ranges and anomalies of remotely sensed sea surface temperature, chlorophyll-a, irradiance, and wave power. Anthropogenic drivers were characterized using empirically derived and modeled datasets of spatial fisheries catch, sedimentation, nutrient input, new development, habitat modification, and invasive species. Within our case...

Land-based source pollutants (LBSP) actively threaten coral reef ecosystems globally. To achieve the greatest conservation outcome at the lowest cost, managers could benefit from appropriate tools that evaluate the benefits (in terms of LBSP reduction) and costs of implementing alternative land management strategies. Here we use a spatially explicit predictive model (InVEST-SDR) that quantifies change in sediment reaching the coast for evaluating the costs and benefits of alternative threat-abatement scenarios. We specifically use the model to examine trade-offs among possible agricultural road repair management actions (water bars to divert runoff and gravel to protect the road surface) across the landscape in West Maui, Hawaii, USA. We investigated changes in sediment delivery to coasts and costs incurred from management decision-making that is (1) cooperative or independent among landowners, and focused on (2) minimizing costs, reducing sediment, or both. The results illuminate which management scenarios most effectively minimize sediment while also minimizing the cost of mitigation efforts. We find targeting specific "hotspots" within all individual parcels is more cost-effective than targeting all road segments. The best outcomes are achieved when landowners cooperate and target cost-effective road repairs, however, a cooperative strategy can be counter-productive in some instances when cost-effectiveness is ignored. Simple models, such as the one developed here, have the potential to help managers make better choices about how to use limited resources.

Marine aquaculture is expanding into deeper offshore environments in response to growing consumer demand for seafood, improved technology, and limited potential to increase wild fisheries catches. Sustainable development of aquaculture will require quantification and minimization of its impacts on other ocean-based activities and the environment through scientifically informed spatial planning. However, the scientific literature currently provides limited direct guidance for such planning. Here, we employ an ecological lens and synthesize a broad multidisciplinary literature to provide insight into the interactions between offshore aquaculture and the surrounding environment across a spectrum of spatial scales. While important information gaps remain, we find that there is sufficient research for informed decisions about the effects of aquaculture siting to achieve a sustainable offshore aquaculture industry that complements other uses of the marine environment.

ABSTRACT Background/Question/Methods The Ocean Tipping Points collaborative research project seeks to understand and characterize tipping points in ocean ecosystems, where a small change in the environment or human activities results in a disproportionate change in the ecosystem. We are further working to develop tools and approaches to integrate this information into marine management. To achieve these goals we are synthesizing and analyzing existing global data on ocean tipping points and their potential indicators, testing whether management based on knowledge of ecosystem thresholds and dynamics results in better outcomes, evaluating regulatory and policy opportunities to incorporate ecosystem thresholds and indicators into marine management, and co-developing and field-testing tools and analytical approaches for management of ecosystems prone to tipping points. Through case studies of Hawaiian coral reefs and the pelagic nearshore ecosystem of Haida Gwaii, British Columbia, we are characterizing ecosystem regimes, their drivers and feedbacks across multiple scales, identifying leading indicators of ecosystem shifts, quantifying threshold responses to key drivers, and evaluating the tradeoffs associated with management alternatives aimed at promoting ecosystem resilience. Results/Conclusions This poster will present results of Phase I of the project and introduce the questions that drive Phase II – case study application. The diverse activities of Phase I have returned a number of key results: (1) We synthesized ~100 examples of marine regime shifts from around the world, which reveal that natural environmental variation and multiple anthropogenic drivers (particularly overharvest and nutrient input) have combined to cause dramatic changes in ecosystems as diverse as oyster reefs, kelp forests, coral reefs, and the open ocean. These shifts occur at scales that matter for ecosystem services and persist on the order of decades. (2) Synthesis of individual stressor responses revealed that non-linear relationships and thresholds are common in pelagic marine ecosystems and may currently be under-estimated. (3) A review of 51 examples of threshold-based management from around the world offers evidence that use of thresholds leads to better ecological outcomes. (4) Finally a review of US federal environmental laws demonstrates ample opportunities to apply a scientific understanding of nonlinear ecosystem dynamics to decisionmaking under existing law and policy as well as opportunities to improve how we respond to tipping points through new policy.

ABSTRACT Background/Question/Methods A growing body of scientific evidence suggests that marine ecosystems around the world experience abrupt and dramatic regime shifts. These ecosystem-level shifts have important implications for ocean management as they are often unforeseen, can be rapid, large, and difficult to reverse and have direct impacts on people’s livelihoods and wellbeing. While regime shifts are increasingly documented across geographies and ecosystems, a comprehensive synthesis of where and when these shifts have occurred and their drivers and consequences in marine ecosystems has not been compiled. Building upon existing efforts (e.g., databases from the Resilience Alliance and Stockholm Resilience Centre), we have assembled a systematic global database of regime shift examples across marine ecosystems, from the intertidal to the open ocean. This database includes regime shifts that were driven both by changes in climatic or oceanic conditions as well as those driven by anthropogenic stressors, like harvest or nutrient input. Our aim is to provide a useful compendium of examples of ecosystem-level tipping points in marine systems, as well as a robust dataset that can help answer fundamental questions about the drivers, mechanisms, and consequences of these shifts. Results/Conclusions Through analysis of over 100 case examples we found numerous commonalities between regime shift attributes across ecosystems, geographies, and spatial and temporal scales. Regime shifts were recorded in kelp, coral, seagrass, pelagic, salt marsh, lagoon, estuarine, rocky reef, tidal flat, and oyster reef ecosystems. Across most ecosystems the resulting shift remained stable on the temporal order of decades (20+ years). Kelp forests were a notable exception, with shifts most often remaining stable on the order of years. The majority of regimes shifts were attributed to one major stressor, with changes in harvest, climate, and eutrophication contributing in over 80% of the shifts recorded. These three major stressors were also the most likely to be cited as acting simultaneously to induce a shift. While ecosystem responses are often classified as following a “linear”, “abrupt” or “hysteretic” path, there is still a need for common, data-driven approaches to characterizing these dynamics, investigating the causal mechanisms, and rigorously testing the role of path dependency in these transitions. We hope that this effort will contribute significantly to the broader goal of helping managers recognize where ecosystem shifts have the potential to occur and how to best anticipate, avoid, or respond to these changes.

ABSTRACT 1.Ecosystem-based management of coral reef fisheries aims to sustainably deliver a diverse portfolio of ecosystem services. This goal can be undermined if the ecosystem shifts into a different state, with altered ecosystem functions and benefits to people. If levels of drivers that cause transitions between states are identified, management measures could be aimed at maintaining drivers below these levels to avoid ecosystem shifts.2.Analysing data from a large number of Caribbean coral reefs (N=2001), suites of non-linear thresholds were identified between metrics of coral reef processes and structure along a gradient of total fish biomass (a proxy for fishing pressure). Several metrics (macroalgal cover, invertivorous fishes, and fish species richness) associated with coral-dominated reefs exhibited thresholds at relatively high fish biomass levels (50–88% of unfished biomass). Other metrics (urchin biomass, ratio of macroalgal to coral cover, herbivorous fishes, and coral cover) showed thresholds at lower fish biomass levels (28–37% of unfished biomass).3.Ratios of total fish biomass in fishing areas to closed areas (unfished biomass) in the Caribbean indicate that reefs may generally be at risk for change at ratios between 0.5 (coral-dominated) and 0.3 (macroalgal-dominated). Similar relationships were found for coral reefs in the Indian Ocean. While these results illustrate thresholds at the scale of the entire Caribbean, assessing local reefs is advisable because biomass levels vary within the region, and reef trajectories depend on past, present and future local conditions.4.Synthesis and applications. If the thresholds in this study are generalizable to scales relevant to management, it may be possible to produce sustainable yield while simultaneously maintaining coral-dominated reefs by restricting fishing mortality to levels that result in biomass ratios near 0.5. Fishing down to biomass ratios near 0.3 may increase the risk of overfishing (resulting in lower long-term yields) and transition to macroalgal-dominated reefs. Thresholds offer a simple and powerful way for managers to operationalize precautionary ecosystem-based fishery management by adaptively limiting fishing pressure in order to (a) maintain desirable coral reef conditions, (b) establish a system-specific target for generating Pretty Good Yield and (c) maintain sustainable multi-species fishery yields.This article is protected by copyright. All rights reserved.

Summary Ecosystem-based management of coral reef fisheries aims to sustainably deliver a diverse portfolio of ecosystem services. This goal can be undermined if the ecosystem shifts into a different state, with altered ecosystem functions and benefits to people. If levels of drivers that cause transitions between states are identified, management measures could be aimed at maintaining drivers below these levels to avoid ecosystem shifts. Analysing data from a large number of Caribbean coral reefs (N = 2001), suites of nonlinear thresholds were identified between metrics of coral reef processes and structure along a gradient of total fish biomass (a proxy for fishing pressure). Several metrics (macroalgal cover, invertivorous fishes and fish species richness) associated with coral-dominated reefs exhibited thresholds at relatively high fish biomass levels (50–88% of unfished biomass). Other metrics (urchin biomass, ratio of macroalgal to coral cover, herbivorous fishes and coral cove...