Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-03-14T13:49:11Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Hedyane M. Pereira.pdf: 1805123 bytes, checksum: cd4b7abba657bce50601a4311f32c163 (MD5) / Made available in DSpace on 2017-03-14T13:49:11Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Hedyane M. Pereira.pdf: 1805123 bytes, checksum: cd4b7abba657bce50601a4311f32c163 (MD5) Previous issue date: 2016-06-30 / CNPQ / Conhecer os primeiros estágios do ciclo de vida dos organismos que representam a base da estrutura recifal, são fundamentais para o entendimento dos fatores que contribuem para a dinâmica populacional em ambientes recifais. O objetivo principal dessa pesquisa foi avaliar o efeito de 17 anos de proibição de pesca e atividade turísticas, nos processos de assentamento e recrutamento de corais e outros organismos bentônicos em Tamandaré, PE. Seiscentos e sessenta e duas placas de cerâmica foram utilizadas como substratos artificiais para avaliar o recrutamento de organismos bentônicos, sendo 336 distribuídas na área fechada de Tamandaré, e 336 distribuídas em quatro recifes da área aberta. Mensalmente, 48 placas foram postas nos ambientes recifais entre outubro de 2014 à julho de 2015 permanecendo imersas por três meses antes de serem analisadas. As superfícies superiores e inferiores de cada placa foram fotografadas e depois analisadas em lupa estereoscópica para o levantamento qualitativo e quantitativo dos organismos bentônicos. Vinte e quatro placas foram colocadas no recife da Ilha da Barra (área fechada) em agosto de 2014 e retiradas em julho de 2015, inicialmente com o objetivo de amostragem piloto, mas depois serviram de experimento para verificar o recrutamento anual de organismos bentônicos da área fechada de Tamandaré. Dados estatísticos foram verificados através da Análise de Variância (ANOVA) no programa Statview 5.0. Para cada recruta de coral, a preferência de assentamento na parte superior e inferior de cada placa e o posicionamento de borda e centro foram registrados e não havendo diferenças significativas entre os respectivos fatores. O maior recrutamento de corais foi encontrado no recife da Ilha da Barra (área fechada), possuindo 2,6 vezes mais recrutas do que nos recifes da área aberta, tendo o maior período de assentamento nos meses do verão. 64,84% do tamanho dos recrutas de corais, mediam entre 1 e 2mm de diâmetro com aproximadamente três meses de imersão de placas, porém não houve diferenças significativas para o crescimento dos corais à medida que mudava o período sazonal. Neste trabalho também foi verificada a densidade média de recrutas de anelídeos, crustáceos, moluscos, equinodermas, poríferas e tunicatos. Foi registrada pela primeira vez para o litoral de Tamandaré, a ascídia Didemmnum psammatodes. A estimativa da cobertura viva e substrato foram analisados, possuindo as algas turf, a maior porcentagem de cobertura viva na amostragem sobreposta, e as algas calcárias maior cobertura viva na amostragem anual. Este estudo fornece evidências de que reservas marinhas podem incentivar a recuperação dos ambientes recifais que foram degradados, o que, por sua vez, pode criar uma série de benefícios no aumento da biomassa de organismos bentônicos e no restabelecimento do ecossistema recifal. / Knowing the first stages of life cycle of the organisms that represents the base of reef structure, are fundamentals to understand the factors that contribute to the populations dynamics in the environmental reef. The main goal of this research was avaluate the effect of 17 years of fishingexclusion and touristic activities, in the process of coral settlement and recruitment, and others benthic organisms in Tamandaré-PE. Six hundred and sixty-two plates were used like artificial substrates to evaluate the benthic organisms recruitment, being 336 distributed in the no-take area of Tamandaré and 336 in five reefs in the take area. Monthly, 48 plates were put in the reefs between October 2014 and July 2015, remaining immersed for three months before analysed. Both upper and lower surfaces of each plate was photographed and after that analysed with a magnifying glass to quantitative and qualitative survey of the benthic organisms. Twenty-four plates were put in the Ilha da Barra reef (closed area) in August 2014 and removed in July 2015, initially with aiming pilot sample, but then served to verify the annual recruitment of benthic organisms in the same area. Statistic data were verified through Analysis of Variance (ANOVA) in the program Statview 5.0. The preference of settlement on upper and lower plate surface and the border and center position, was registered for each coral recruit and the analysis showed have no significant differences between the factors. The higher coral recruitment was found in the Ilha da Barra reef, with 2,6 time more recruits than not protected reefs, have higher settlement in the summer. 64,84% of coral recruit size, measured between 1 and 2 mm of diameter with approximatly three months-immersed, but had not significant diferences to growth as the changed the seasonal period. In this research, it was also verified the avarage density of annelids, barnacles, mollusks, echinoderms, sponges and ascidians. For the first time in Tamandaré’s region it was registered the ascidan Didemmnum psammatodes. The estimate alive and substrate coverage was analysed, they have Turf algae, the higher percentage of covarage in the overlapping-sampling and the crustose coralline algae a higher percentage coverage in the annual-sampling. This study provides evidences that marine reserves can motivate a recover of reef environmental that was degraded, and then, not only create a serie of benefits on biomass but also the re-establishment of the coral reef ecosystem.

The resilience of coral reefs depends, among others, upon local physical and biological characteristics. This dissertation focused on how herbivory, structural complexity, and sedimentation can impact the structure, function, and, ultimately, resilience of Caribbean coral reefs. We filled an important knowledge gap related to trophic niche and ecological roles of surgeonfishes (A. coeruleus and A. tractus), two of the most important herbivorous fishes in the Caribbean. We showed that both species feed primarily on turf algae preventing further progression of algal succession while A. tractus may also help reduce macroalgal abundance by targeting common macroalgal species such as Dictyota spp. We used a factorial experiment to analyze the interactive effects of herbivory (exclosure vs. open plots) and reef structural complexity (vertical vs. horizontal substrate orientation), on the development of benthic communities. We found that vertical substrates were quickly dominated by crustose algae regardless of herbivory treatment while succession of horizontal substrates was determined by herbivory. Our results suggest that at small scale, reef complexity is a major factor determining algal community structure. We investigated why, despite high levels of herbivory, coral cover in South Florida has failed to recover. We surveyed benthic composition, grazing and abiotic characteristics along six spur and groove reefs in the Florida Keys. Using boosted regression tree analyses, we found that sediment abundance was the best predictor of both juvenile and adult corals, which could explain the failure of coral recovery. We studied spatial and temporal changes of reef communities of reefs in Havana, Cuba where global and local stressors have affected coral communities while overfishing and nutrient enrichment has led to low herbivory levels. Our surveys revealed a region-wide high abundance of algae (~60%) as a consequence of heavy overfishing with likely negative consequences on coral recovery. In summary, my dissertation showed context-depend effects of herbivory, structural complexity, and sediment on Caribbean coral reefs. While reduction of herbivory can often suppress coral recovery, on coral reefs with robust herbivore populations, physical factors such as structural complexity and sediment may still limit coral recovery and fundamentally impact reef resilience.

Coral reef recovery following a disturbance relies heavily on the restoration of coral cover, via growth of existing colonies and the successful recruitment of new corals. In well-connected reef networks, recruits may be sourced from neighboring reefs. In contrast, coral recruitment on geographically isolated reefs is reliant on adult corals at that location, which may limit recovery rates following mass coral mortality events. Such mortality events are increasingly caused by climate change induced temperature anomalies, which are overlaid on the local chronic human disturbances that already affect most of the world’s coral reefs. In this thesis, I exploit a natural ecosystem-scale experiment to examine how multiple anthropogenic stressors impact densities of coral recruits and small corals (e.g., juveniles; 5 cm) on Kiritimati (Christmas Island, Republic of Kiribati), an isolated atoll in the central equatorial Pacific Ocean. Specifically, I used benthic survey videos from before, during, and one year following the 2015-2016 El Niño and coral settlement tiles deployed during the three years after the event at 22 sites across the island, to quantify small corals and coral recruits, respectively. Local chronic stress negatively impacted small corals, with densities 47% lower at sites exposed to very high levels of chronic stress prior to the heat stress. The El Niño further resulted in a 56% loss of small corals, particularly for competitive coral species. Following the event, stress tolerant small corals rebounded to pre-El Niño densities within a year, whereas competitive and small corals overall had non-significant increases. I also quantified a low recruitment rate of 8.31 recruits m-2 per year (± 1.9 SE) during the three years following the El Niño compared to previous studies around the Pacific; recruits were genetically identified as primarily belonging to the stress tolerant family Agariciidae and the competitive genus Pocillopora. Local human disturbance also impacted coral recruitment with densities significantly lower at those with the greatest local chronic disturbance, together suggesting that local disturbance impedes post-settlement survival of recruits and the resilience of young corals during acute stress events. With increased net primary productivity, densities of both small corals and recruits (non-significant) also increased, which could reflect the positive influence of coral heterotrophic nutrition supplements during and after stress events, increasing survivability. Despite very low overall coral recruitment, all island regions did have some recruits, but Vaskess Bay (a bay region on the southern part of the island) had the highest densities. Overall these results indicate the negative consequences combined chronic and acute stressors can have on coral recruits, small corals, and accompanying coral resilience. When viewed together, this work suggests how the resilience is compromised by chronic stressors on Kiritimati and that the recovery trajectory may be variable across the disturbance gradient. Thus, local reef management may provide an avenue for enhancing recovery rates as acute temperature anomalies increase in frequency under our current climate trajectory. / Graduate / 2021-01-14

Over the past few decades, coral cover has declined worldwide due to overfishing, disease, and storms, and these effects have been exacerbated by ocean warming and acidification. Corals are extremely susceptible to these changes because they are already living close to their thermal and aragonite saturation thresholds. Ocean warming and acidification (OAW) may also impact coral survival and growth by impacting their settlement cues. Coral larvae use crustose coralline algae (CCA) and their associated biofilms as cues for settlement, i.e., habitat selection. Settlement cues can also be negatively affected by increased water temperature and acidity. It was hypothesized that the impacts of OAW on settlement substrate can further threaten coral persistence by altering/inhibiting larval settlement and potentially decreasing the post-settlement survival and growth of coral recruits. In this study, we 1) assessed the effect of substrate quality (substrate conditioned in ambient or OAW conditions) on settlement of A. agaricites larvae, 2) determined the effect of substrate quality on post-settlement survival and growth of A. agaricites recruits, and 3) determined the effect of ocean warming and acidification on the post-settlement survival and growth of A. agaricites recruits. Aragonite settlement tiles were placed offshore for one month to accrue CCA and associated biofilms, and were then conditioned in either ambient (29°C, 8.2 pH) or predicted future oceanic conditions (31°C, 7.9 pH) conditions for 7 – 10 days. Agaricia agaricites larvae were then introduced to the settlement tiles, and their settlement percentage was calculated. Once a week for 12 weeks after larval settlement, the size, survival, and pigmentation of A. agaricites recruits was recorded. Larvae settled marginally more on optimally conditioned tiles than on tiles previously exposed to OAW conditions (p=0.053). The survival of coral recruits in OAW conditions was greatly reduced, their growth was very limited, and they became paler over time. When reared in ambient conditions, recruits on OAW treated substrate initially displayed higher survival rates than recruits on ambient treated substrate. After 3 weeks in ambient conditions, however, survival rates were similar for recruits on ambient and OAW treated substrate; their growth curves were very similar, and coral recruits became more pigmented over time. Ocean warming and acidification conditions not only directly impacted the growth, survival, and pigmentation of A. agaricites recruits, but it also indirectly affected larval 5 settlement by likely altering microbial composition in bacterial biofilms on the settlement tiles. These results indicate that future conditions of ocean warming and acidification can be deleterious for A. agaricites, particularly after settlement. If the early life stages of scleractinian corals are negatively affected by OAW conditions, successful recruitment throughout the Caribbean and Florida Reef Tract could decrease. As a result, recovery from disturbances could be hindered, thus compromising the sustainability of many coral species and other marine ecosystems that depend on coral reefs for protection, habitat, and food.

Coral reefs are being negatively impacted by various causes worldwide, and direct intervention is often warranted following disturbance to restore or replace lost ecosystem structure and function. An experimental coral reef restoration study involving standardized artificial reef modules (ReefballsTM) was conducted in Mexico’s Yucatan Peninsula in the towns of Puerto Morelos and Akumal. The purpose was to explore the use of artificial structure for restoration and mitigation applications in a highly diverse and dynamic Caribbean coral reef environment by applying and evaluating the performance of select experimental treatments hypothesized to accelerate development of the associated biota. The first treatment consisted of invertebrate enhancing artificial substrate padding material, which provided structurally complex refuge space for mobile epifaunal/infaunal invertebrates and other benthic organisms. The second treatment consisted of coral transplants, intended to provide additional structural complexity and kick-start development of stony coral populations. The third treatment consisted of settlement plates which were intended to provide data on coral recruitment and survival rates. Multiple hypotheses relating to the interactions between experimental treatments and the resulting macroalgal, non-coral invertebrate, stony coral, and coral reef fish assemblages were examined, and comparisons were made between natural and artificial substrates. In Puerto Morelos there were 40 modules; 10 controls and 10 of each of 3 treatments: substrate pads, coral transplants, and settlement plates. In Akumal there were 12 modules; 6 controls and 3 of each of 2 treatments: substrate pads and settlement plates. Following module deployment, 6 biannual monitoring trips were made over the course of three years to assess the development of the biota, with a final 7th trip made six years post-deployment. Divers conducted non-destructive visual surveys to evaluate total abundance, species richness, size class distribution, and assemblage structure of coral reef fishes. Other monitoring work included coral recruit surveys, mobile epifaunal invertebrate collections from substrate pads, and digital imaging of coral transplants, natural reef reference corals, and benthic quadrat areas. Hurricane Dean compromised the Akumal study site during the first year of the study, but Puerto Morelos was unaffected. There the modules developed biotic assemblages that differed from what was found on the natural reef, and the data suggests that the substrate pads may have had an effect on the development of faunal assemblages. Lobophora variegata macroaglae and Desmapsamma anchorata sponge were the major contributors to benthic community composition, and both had significantly greater coverage on the substrate pads treatment modules. Lobophora grew rapidly and peaked within the first year, while sponges increased steadily throughout the first three years of the study, surpassing the coverage of macroalgae before the end of the second year, much to the detriment of coral transplants and many coral recruits. By the end of the study, over 75% of the transplants were overgrown by D. anchorata, and density of new coral recruits on the Pads treatment modules was lower than the other treatments and controls. Coral recruitment was dominated by Porites astreoides on all treatments and controls, and the number of corals increased steadily throughout the study. The controls had consistently greater numbers of corals than the treatments, as well as lower percent coverage of macroalgae and sponges. Total abundance and species richness of reef fishes was generally unaffected by the treatments. However, at the family and species level, several differences were detected, particularly for the substrate pads treatment and to a lesser extent for the coral transplants treatment. For future restoration or mitigation efforts utilizing similar or identical treatments to artificial substrates, this study suggests that, in the absence of routine maintenance, greater success may be achieved after waiting several years post-deployment for the initial wave of unchecked growth by benthic organisms (i.e., macroalgae and sponges) to reach a balance point before a large investment of resources is devoted to coral transplanting. Further recommendations include routine monthly or quarterly on-site maintenance to enhance transplant survival, as well as a longer monitoring window to assess community development in response to experimental treatments. The results of this study suggest that the experimental treatments did indeed have an effect on the biota, but whether or not the effect was beneficial largely depends upon perspective. The Pads treatment in particular had the greatest effect on both reef fish and benthic community development, however, it was not beneficial for stony coral recruitment. Additional research is needed to fully understand the long-term performance and effects of the padding material on biotic assemblage development for future restoration or mitigation projects.