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Dive into the research topics where Gabby N. Ahmadia is active.

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Featured researches published by Gabby N. Ahmadia.


Nature | 2017

Capacity shortfalls hinder the performance of marine protected areas globally

David Gill; Michael B. Mascia; Gabby N. Ahmadia; Louise Glew; Sarah E. Lester; Megan Barnes; Ian D. Craigie; Emily S. Darling; Christopher M. Free; Jonas Geldmann; Susie Holst; Olaf P. Jensen; Alan T. White; Xavier Basurto; Lauren Coad; Ruth D. Gates; Greg Guannel; Peter J. Mumby; Hannah Thomas; Sarah Whitmee; Stephen Woodley; Helen E. Fox

Marine protected areas (MPAs) are increasingly being used globally to conserve marine resources. However, whether many MPAs are being effectively and equitably managed, and how MPA management influences substantive outcomes remain unknown. We developed a global database of management and fish population data (433 and 218 MPAs, respectively) to assess: MPA management processes; the effects of MPAs on fish populations; and relationships between management processes and ecological effects. Here we report that many MPAs failed to meet thresholds for effective and equitable management processes, with widespread shortfalls in staff and financial resources. Although 71% of MPAs positively influenced fish populations, these conservation impacts were highly variable. Staff and budget capacity were the strongest predictors of conservation impact: MPAs with adequate staff capacity had ecological effects 2.9 times greater than MPAs with inadequate capacity. Thus, continued global expansion of MPAs without adequate investment in human and financial capacity is likely to lead to sub-optimal conservation outcomes.


Scientific Reports | 2016

Local-scale projections of coral reef futures and implications of the Paris Agreement

Ruben van Hooidonk; Jeffrey A. Maynard; Jerker Tamelander; Jamison M. Gove; Gabby N. Ahmadia; Laurie Raymundo; Gareth J. Williams; Scott F. Heron; Serge Planes

Increasingly frequent severe coral bleaching is among the greatest threats to coral reefs posed by climate change. Global climate models (GCMs) project great spatial variation in the timing of annual severe bleaching (ASB) conditions; a point at which reefs are certain to change and recovery will be limited. However, previous model-resolution projections (~1 × 1°) are too coarse to inform conservation planning. To meet the need for higher-resolution projections, we generated statistically downscaled projections (4-km resolution) for all coral reefs; these projections reveal high local-scale variation in ASB. Timing of ASB varies >10 years in 71 of the 87 countries and territories with >500 km2 of reef area. Emissions scenario RCP4.5 represents lower emissions mid-century than will eventuate if pledges made following the 2015 Paris Climate Change Conference (COP21) become reality. These pledges do little to provide reefs with more time to adapt and acclimate prior to severe bleaching conditions occurring annually. RCP4.5 adds 11 years to the global average ASB timing when compared to RCP8.5; however, >75% of reefs still experience ASB before 2070 under RCP4.5. Coral reef futures clearly vary greatly among and within countries, indicating the projections warrant consideration in most reef areas during conservation and management planning.


Molecular Phylogenetics and Evolution | 2013

Evolution of microhabitat association and morphology in a diverse group of cryptobenthic coral reef fishes (Teleostei: Gobiidae: Eviota)

Luke Tornabene; Gabby N. Ahmadia; Michael L. Berumen; Jamaluddin Jompa; Frank Pezold

Gobies (Teleostei: Gobiidae) are an extremely diverse and widely distributed group and are the second most species rich family of vertebrates. Ecological drivers are key to the evolutionary success of the Gobiidae. However, ecological and phylogenetic data are lacking for many diverse genera of gobies. Our study investigated the evolution of microhabitat association across the phylogeny of 18 species of dwarfgobies (genus Eviota), an abundant and diverse group of coral reef fishes. In addition, we also explore the evolution of pectoral fin-ray branching and sensory head pores to determine the relationship between morphological evolution and microhabitat shifts. Our results demonstrate that Eviota species switched multiple times from a facultative hard-coral association to inhabiting rubble or mixed sand/rubble habitat. We found no obvious relationship between microhabitat shifts and changes in pectoral fin-ray branching or reduction in sensory pores, with the latter character being highly homoplasious throughout the genus. The relative flexibility in coral-association in Eviota combined with the ability to move into non-coral habitats suggests a genetic capacity for ecological release in contrast to the strict obligate coral-dwelling relationship commonly observed in closely related coral gobies, thus promoting co-existence through fine scale niche partitioning. The variation in microhabitat association may facilitate opportunistic ecological speciation, and species persistence in the face of environmental change. This increased speciation opportunity, in concert with a high resilience to extinction, may explain the exceptionally high diversity seen in Eviota compared to related genera in the family.


Philosophical Transactions of the Royal Society B | 2015

Integrating impact evaluation in the design and implementation of monitoring marine protected areas.

Gabby N. Ahmadia; Louise Glew; Mikaela Provost; David Gill; Nur Ismu Hidayat; Sangeeta Mangubhai; Purwanto; Helen E. Fox

Quasi-experimental impact evaluation approaches, which enable scholars to disentangle effects of conservation interventions from broader changes in the environment, are gaining momentum in the conservation sector. However, rigorous impact evaluation using statistical matching techniques to estimate the counterfactual have yet to be applied to marine protected areas (MPAs). While there are numerous studies investigating ‘impacts’ of MPAs that have generated considerable insights, results are variable. This variation has been linked to the biophysical and social context in which they are established, as well as attributes of management and governance. To inform decisions about MPA placement, design and implementation, we need to expand our understanding of conditions under which MPAs are likely to lead to positive outcomes by embracing advances in impact evaluation methodologies. Here, we describe the integration of impact evaluation within an MPA network monitoring programme in the Birds Head Seascape, Indonesia. Specifically we (i) highlight the challenges of implementation ‘on the ground’ and in marine ecosystems and (ii) describe the transformation of an existing monitoring programme into a design appropriate for impact evaluation. This study offers one potential model for mainstreaming impact evaluation in the conservation sector.


PLOS Biology | 2017

Marine Reserve Targets to Sustain and Rebuild Unregulated Fisheries

Nils C. Krueck; Gabby N. Ahmadia; Hugh P. Possingham; Cynthia Riginos; Eric A. Treml; Peter J. Mumby

Overfishing threatens the sustainability of coastal marine biodiversity, especially in tropical developing countries. To counter this problem, about 200 governments worldwide have committed to protecting 10%–20% of national coastal marine areas. However, associated impacts on fisheries productivity are unclear and could weaken the food security of hundreds of millions of people who depend on diverse and largely unregulated fishing activities. Here, we present a systematic theoretic analysis of the ability of reserves to rebuild fisheries under such complex conditions, and we identify maximum reserve coverages for biodiversity conservation that do not impair long-term fisheries productivity. Our analysis assumes that fishers have no viable alternative to fishing, such that total fishing effort remains constant (at best). We find that realistic reserve networks, which protect 10%–30% of fished habitats in 1–20 km wide reserves, should benefit the long-term productivity of almost any complex fishery. We discover a “rule of thumb” to safeguard against the long-term catch depletion of particular species: individual reserves should export 30% or more of locally produced larvae to adjacent fishing grounds. Specifically on coral reefs, where fishers tend to overexploit species whose dispersal distances as larvae exceed the home ranges of adults, decisions on the size of reserves needed to meet the 30% larval export rule are unlikely to compromise the protection of resident adults. Even achieving the modest Aichi Target 11 of 10% “effective protection” can then help rebuild depleted catch. However, strictly protecting 20%–30% of fished habitats is unlikely to diminish catch even if overfishing is not yet a problem while providing greater potential for biodiversity conservation and fishery rebuilding if overfishing is substantial. These findings are important because they suggest that doubling or tripling the only globally enforced marine reserve target will benefit biodiversity conservation and higher fisheries productivity where both are most urgently needed.


Marine Biodiversity | 2012

Cryptobenthic fish biodiversity and microhabitat use in healthy and degraded coral reefs in SE Sulawesi, Indonesia

Gabby N. Ahmadia; Frank Pezold

Cryptobenthic fishes occur in high densities on coral reefs, though due to their small size and cryptic nature they are often overlooked when quantifying reef biodiversity. This study examines their distribution on shallow reefs in SE Sulawesi, Indonesia, and assesses changes in habitat utilization when subject to reef degradation. Cryptic fishes were sampled from dominant microhabitat types in healthy and degraded reefs within the Wakatobi Marine National Park located in SE Sulawesi. High biodiversity of cryptobenthic fishes was found with 50 species representing 13 families. Traditional metrics (i.e. density, diversity) showed few differences between healthy and degraded reefs, though further investigations revealed differences occurred in community composition. Additional analyses of individual species demonstrated that reef degradation could have positive or negative effects on populations depending on type and strength of habitat associations. In summary, cryptobenthic fishes are altering their habitat use on degraded reefs, which will likely have repercussions on coral reef dynamics.


Ecological Applications | 2017

Incorporating larval dispersal into MPA design for both conservation and fisheries

Nils C. Krueck; Gabby N. Ahmadia; Alison Green; Geoffrey P. Jones; Hugh P. Possingham; Cynthia Riginos; Eric A. Treml; Peter J. Mumby

Larval dispersal by ocean currents is a critical component of systematic marine protected area (MPA) design. However, there is a lack of quantitative methods to incorporate larval dispersal in support of increasingly diverse management objectives, including local population persistence under multiple types of threats (primarily focused on larval retention within and dispersal between protected locations) and benefits to unprotected populations and fisheries (primarily focused on larval export from protected locations to fishing grounds). Here, we present a flexible MPA design approach that can reconcile multiple such potentially conflicting management objectives by balancing various associated treatments of larval dispersal information. We demonstrate our approach based on alternative dispersal patterns, combinations of threats to populations, management objectives, and two different optimization strategies (site vs. network-based). Our outcomes highlight a consistently high effectiveness in selecting priority locations that are self-replenishing, inter-connected, and/or important larval sources. We find that the opportunity to balance these three dispersal attributes flexibly can help not only to prevent meta-population collapse, but also to ensure effective fisheries recovery, with average increases in the number of recruits at fishing grounds at least two times higher than achieved by standard habitat-based or ad-hoc MPA designs. Future applications of our MPA design approach should therefore be encouraged, specifically where management tools other than MPAs are not feasible.


Systematics and Biodiversity | 2013

Four new species of dwarfgobies (Teleostei: Gobiidae: Eviota) from the Austral, Gambier, Marquesas and Society Archipelagos, French Polynesia

Luke Tornabene; Gabby N. Ahmadia; Jeffrey T. Williams

Four new species of Eviota (Teleostei: Gobiidae) are described from French Polynesia. Eviota hinanoae occurs from the Gambier, Austral and Society Archipelagos and differs from its closest relatives primarily in sensory pore pattern, having cuplike male urogenital papilla, and in lacking prominent dark pigmentation on the base of the pectoral fin. Three other new species, E. dorsimaculata, E. lacrimosa and E. deminuta, are known only from the Marquesas Islands and are distinguished from congeners by differences in pigmentation, sensory pore pattern, urogenital papilla shape, the number of rays in the dorsal and anal fins, and the length of the fifth pelvic-fin ray. Eviota deminuta represents one of the smallest known species of Eviota and features reductions in several morphological characters, including the loss of all head pores. Three of the new species are included in a phylogenetic analysis based on mitochondrial cytochrome c oxidase-I, along with 21 additional species of Eviota.


International Journal of Environmental Research and Public Health | 2015

Delineating Biophysical Environments of the Sunda Banda Seascape, Indonesia

Mingshu Wang; Gabby N. Ahmadia; Iliana Chollett; Charles Huang; Helen E. Fox; Anton Wijonarno; Marguerite Madden

The Sunda Banda Seascape (SBS), located in the center of the Coral Triangle, is a global center of marine biodiversity and a conservation priority. We proposed the first biophysical environmental delineation of the SBS using globally available satellite remote sensing and model-assimilated data to categorize this area into unique and meaningful biophysical classes. Specifically, the SBS was partitioned into eight biophysical classes characterized by similar sea surface temperature, chlorophyll a concentration, currents, and salinity patterns. Areas within each class were expected to have similar habitat types and ecosystem functions. Our work supplemented prevailing global marine management schemes by focusing in on a regional scale with finer spatial resolution. It also provided a baseline for academic research, ecological assessments and will facilitate marine spatial planning and conservation activities in the area. In addition, the framework and methods of delineating biophysical environments we presented can be expanded throughout the whole Coral Triangle to support research and conservation activities in this important region.


Annals of the New York Academy of Sciences | 2017

A novel framework for analyzing conservation impacts: evaluation, theory, and marine protected areas.

Michael B. Mascia; Helen E. Fox; Louise Glew; Gabby N. Ahmadia; Arun Agrawal; Megan Barnes; Xavier Basurto; Ian D. Craigie; Emily S. Darling; Jonas Geldmann; David Gill; Susie Holst Rice; Olaf P. Jensen; Sarah E. Lester; Patrick McConney; Peter J. Mumby; Mateja Nenadovic; John E. Parks; Robert S. Pomeroy; Alan T. White

Environmental conservation initiatives, including marine protected areas (MPAs), have proliferated in recent decades. Designed to conserve marine biodiversity, many MPAs also seek to foster sustainable development. As is the case for many other environmental policies and programs, the impacts of MPAs are poorly understood. Social–ecological systems, impact evaluation, and common‐pool resource governance are three complementary scientific frameworks for documenting and explaining the ecological and social impacts of conservation interventions. We review key components of these three frameworks and their implications for the study of conservation policy, program, and project outcomes. Using MPAs as an illustrative example, we then draw upon these three frameworks to describe an integrated approach for rigorous empirical documentation and causal explanation of conservation impacts. This integrated three‐framework approach for impact evaluation of governance in social–ecological systems (3FIGS) accounts for alternative explanations, builds upon and advances social theory, and provides novel policy insights in ways that no single approach affords. Despite the inherent complexity of social–ecological systems and the difficulty of causal inference, the 3FIGS approach can dramatically advance our understanding of, and the evidentiary basis for, effective MPAs and other conservation initiatives.

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Helen E. Fox

World Wide Fund for Nature

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Peter J. Mumby

University of Queensland

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Louise Glew

World Wide Fund for Nature

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Megan Barnes

University of Queensland

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David Gill

University of the West Indies

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Nils C. Krueck

University of Queensland

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