Coastal Populations Research Articles

Population genomics of coastal Pacific Hake

AbstractObjectiveUnderstanding the genetic structure of harvested fishery species is crucial for accurate stock assessments and effective management strategies. There have been several rangewide population genetic analyses of Pacific Hake Merluccius productus; however, a thorough focus on the heavily harvested coastal stock off the west coast of North America is missing. Recent observations of spatial–temporal variability in life history and migratory patterns of the coastal population have brought into question whether this variation may be related to genetic differentiation.MethodsHere, we used restriction site‐associated DNA sequencing markers to thoroughly assess the potential for spatial–temporal genetic differentiation in the coastal stock of Pacific Hake. We sampled during different seasons from British Columbia down to the U.S.–Mexico border over multiple years on what traditionally have been thought to constitute spawning and feeding grounds, resulting in the most comprehensive assessment of coastal Pacific Hake population structure to date.ResultGenerally, our results suggest very weak to no structure among coastal spatial–temporal sites and corroborate previous findings of strong differentiation between coastal and Salish Sea populations. The lack of structure among coastal sites is likely due to significant amounts of gene flow in this highly migratory population.ConclusionThese findings align with the ongoing management strategy for coastal Pacific Hake, which is based on an annual stock assessment that considers the coastal stock homogenous and distinct from the Salish Sea population. The understanding that management units indeed match genetic populations provides managers with additional confidence in existing management strategy.

RADseq data reveal widespread historical introgression in four familiar North American songbirds.

Population genetic structure is influenced by a combination of contemporary and historical events; however, this structure can be complicated by ongoing gene flow. While it is well known that contemporary hybridization occurs frequently among many closely related species, it often remains uncertain as to which populations are involved in introgression events, and this can be even more difficult to infer when introgression is historical. Here we use restriction-site associated DNA sequencing to look at the level of introgression among four species of songbirds in North America: the black-capped, mountain, boreal, and chestnut-backed chickadee. Samples from both sympatric and allopatric sites across the species' ranges supported limited ongoing mixing among the four species with Bayesian clustering and principal component analyses. In contrast, f4-statistics and admixture graphs revealed extensive historical introgression among geographically structured populations. Almost all historical admixture events were among populations west of the Rocky Mountains, and almost all populations west of the Rocky Mountains, excluding island and coastal populations, showed evidence of historical admixture. The inclusion of all four chickadee species proved crucial in differentiating which species were involved in hybridization events to avoid erroneous conclusions. Taken together, the results suggest a complex pattern of divergence with gene flow.

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Abstract Long‐term systematic records of cetacean strandings are valuable indicators of temporal responses of specific cetacean populations and communities to natural or anthropogenic pressures. They also help guide management objectives and conservation actions. Generalized additive models (GAMs) were used to analyse 10 years of systematic and opportunistic surveys of Guiana dolphin strandings in the Amazon Estuary region, Northern Brazil. The spatial distribution of strandings was assessed through kernel density maps, and age‐at‐death structure of this population was described. The model results revealed marked seasonality in the strandings and, by extension, the mortality of Guiana dolphins in the Amazon Estuary. This seasonality varied between the inner estuarine regions and Atlantic coastal area, reflecting the environment's characteristics. Long‐term decline of strandings in the Amazon Estuary inner region and unusual high mortality of young sexually mature individuals were detected. These results, besides the high stranding rate detected for the species, are mostly attributed to the species' interaction with intense fishing activity in the region. Conservation efforts should consider the seasonality of Guiana dolphin strandings in the Amazon Estuary. The systematic monitoring of strandings, especially in high‐frequency areas, is recommended for assessing long‐term species mortality. Additionally, implementing management actions related to the species' interaction with fishing activities, such as regulatory enhancements, gillnet modifications and seasonal no‐fishing zones, is advised. Educational campaigns targeting fishermen and riverine communities are essential to reduce bycatch and the folkloric use of the species. This study underscores the effectiveness of stranding data as a source of biological and ecological information, and as a tool for understanding human actions affecting coastal populations of aquatic mammals. It emphasizes the need for urgent studies to characterize this population, clarify the influence of bycatch as an anthropogenic pressure and implement effective conservation actions to preserve the Guiana dolphin population.

Differentiated genomic footprints suggest isolation and long-distance migration of Hmong-Mien populations

BackgroundThe underrepresentation of Hmong-Mien (HM) people in Asian genomic studies has hindered our comprehensive understanding of the full landscape of their evolutionary history and complex trait architecture. South China is a multi-ethnic region and indigenously settled by ethnolinguistically diverse HM, Austroasiatic (AA), Tai-Kadai (TK), Austronesian (AN), and Sino-Tibetan (ST) people, which is regarded as East Asia’s initial cradle of biodiversity. However, previous fragmented genetic studies have only presented a fraction of the landscape of genetic diversity in this region, especially the lack of haplotype-based genomic resources. The deep characterization of demographic history and natural-selection-relevant genetic architecture of HM people was necessary.ResultsWe reported one HM-specific genomic resource and comprehensively explored the fine-scale genetic structure and adaptative features inferred from the genome-wide SNP data of 440 HM individuals from 33 ethnolinguistic populations, including previously unreported She. We identified solid genetic differentiation between HM people and Han Chinese at 7.64‒15.86 years ago (kya) and split events between southern Chinese inland (Miao/Yao) and coastal (She) HM people in the middle Bronze Age period and the latter obtained more gene flow from Ancient Northern East Asians. Multiple admixture models further confirmed that extensive gene flow from surrounding ST, TK, and AN people entangled in forming the gene pool of Chinese coastal HM people. Genetic findings of isolated shared unique ancestral components based on the sharing alleles and haplotypes deconstructed that HM people from the Yungui Plateau carried the breadth of previously unknown genomic diversity. We identified a direct and recent genetic connection between Chinese inland and Southeast Asian HM people as they shared the most extended identity-by-descent fragments, supporting the long-distance migration hypothesis. Uniparental phylogenetic topology and network-based phylogenetic relationship reconstruction found ancient uniparental founding lineages in southwestern HM people. Finally, the population-specific biological adaptation study identified the shared and differentiated natural selection signatures among inland and coastal HM people associated with physical features and immune functions. The allele frequency spectrum of cancer susceptibility alleles and pharmacogenomic genes showed significant differences between HM and northern Chinese people.ConclusionsOur extensive genetic evidence combined with the historical documents supported the view that ancient HM people originated from the Yungui regions associated with ancient “Three-Miao tribes” descended from the ancient Daxi-Qujialing-Shijiahe people. Then, some have recently migrated rapidly to Southeast Asia, and some have migrated eastward and mixed respectively with Southeast Asian indigenes, Liangzhu-related coastal ancient populations, and incoming southward ST people. Generally, complex population migration, admixture, and adaptation history contributed to the complicated patterns of population structure of geographically diverse HM people.

The global long-term effects of storm surge flooding on human settlements in coastal areas

People in low-lying coastal areas live under the great threat of damage due to coastal flooding from tropical cyclones. Understanding how coastal population settlements react to such events is of high importance for society to consider future adaptation strategies. Here we generate a new global hydrodynamic data set on tropical cyclone-generated storm surge flooding for the period 1851–2020. By combining this data with spatial data on human populations, we analyze the influence of the depth of storm surge flooding on the rural, urban, and total populations in low elevation coastal zones from 1941–2010. We find that in response to a one standard deviation increase in storm surge flooding depth (0.43 m), the exposed population in a 10×10 km low elevation coastal zone decreases by around 970 individuals on average per decade. This reduction corresponds to 9% of the average population living in an exposed grid cell. Tropical cyclone generated wind speed and rainfall do not influence the relocation of coastal populations. The majority of the threatened population lives in Eastern, South–Eastern, and Southern Asia. We show that the exposed coastal population appears to have adapted over time by reducing its exposure in recent decades. This finding applies to all regions other than North America, Oceania, and Western Asia.

The biometry of Cardisoma crassum (Brachyura: Gecarcinidae) from two folkloric festivals in Veraguas, Panama

This study explores the biometry of Cardisoma crassum individuals presented in two folkloric festivals within the Montijo Gulf in 2022 and 2023. Crabs in the Rio de Jesús (RJ) festival from 2022 exhibited a male biased sex ratio, contrasting Montijo's (MO) even sex ratio in 2023. Carapace widths were similar between festivals (RJ, 65.59 ± 6.56 mm; MO: 64.29 ± 5.92 mm). Sex-based size variations were consistent within years but not between years. Localities showed significant size and sex ratio differences, while transportation distance to the festival venues did not correlate with crab size. Additionally, a comparison between current data and previous studies from 2014–2015, 2021 and 2022, highlighted size differences among sites might not be related to yearly increasing crab demand; instead, site-specific extraction pressure may be an underlying factor. Festivals consumed approximately 198 crab bundles in Rio de Jesús in 2022 (≈ 2,376 individuals) and an estimated 207 bundles in Montijo in 2023 (≈ 2,484 individuals). This study unveils complex dynamics in C. crassum populations at the local level, encompassing sex ratios, size variations, and economic dimensions within festival contexts. Understanding these multifaceted dynamics is crucial for effectively managing these coastal crab populations in the future.

Divergent Selection in Low Recombination Regions Shapes the Genomic Islands in Two Incipient Shorebird Species.

Speciation in the face of gene flow is usually associated with a heterogeneous genomic landscape of divergence in nascent species pairs. However, multiple factors, such as divergent selection and local recombination rate variation, can influence the formation of these genomic islands. Examination of the genomic landscapes of species pairs that are still in the early stages of speciation provides an insight into this conundrum. In this study, population genomic analyses were undertaken using a wide range of sampling and whole-genome resequencing data from 96 unrelated individuals of Kentish plover (Charadrius alexandrinus) and white-faced plover (Charadrius dealbatus). We suggest that the two species exhibit varying levels of population admixture along the Chinese coast and on the Taiwan Island. Genome-wide analyses for introgression indicate that ancient introgression had occurred in Taiwan population, and gene flow is still ongoing in mainland coastal populations. Furthermore, we identified a few genomic regions with significant levels of interspecific differentiation and local recombination suppression, which contain several genes potentially associated with disease resistance, coloration, and regulation of plumage molting and thus may be relevant to the phenotypic and ecological divergence of the two nascent species. Overall, our findings suggest that divergent selection in low recombination regions may be a main force in shaping the genomic islands in two incipient shorebird species.

Trajectories of Environmental Migrants: Understanding Migration Destinations of the Coastal Population in Kerala, India

Trajectories of Environmental Migrants: Understanding Migration Destinations of the Coastal Population in Kerala, India

Effect of prebiotics, probiotics, and synbiotics on gut microbiome in diabetes among coastal communities

Cutting-edge research on oceans and human health is enhancing our comprehension of disease-causing organisms in coastal ecosystems. Coastal areas are affected by pollution resulting from the changes in hydrology and land utilization. In the coastal population, an elevated incidence of diabetes was observed. Diabetes mellitus is a prominent metabolic disease that is causing major burdens for patients as well as physicians. Diabetes is an intricate condition that encompasses several molecular pathways associated with the gut microbiome. The gut microbiome significantly influences the permeability of the gastrointestinal mucosa. Alterations in the wide range of gut microbiomes have been associated with various health issues including diabetes. The two major contributors to type 2 diabetes are insulin resistance and inflammation which may result in metabolic dysregulation due to dysbiosis. Due to gut dysbiosis, diabetes may show high prevalence in individuals living in coastal areas. The correlation between dysbiosis and diabetes can be made, especially considering probiotics have been demonstrated to have some impact in helping diabetic patients with their interrupted metabolism revert to normal. Probiotic intake has reportedly resulted in improved metabolic control among patients with type 2 diabetes. Prebiotics can be non-digestible carbohydrates that are naturally extracted or synthetically produced. Uses of synbiotics show a synergistic impact on type 2 diabetes by altering the gut environment. In coastal communities, the potential effects of probiotic, prebiotic, and synbiotic therapy on the gut microbiome of diabetic patients have been investigated. Although these therapies have demonstrated encouraging results in coastal areas, more research is needed to fully understand their implications for controlling diabetes in this setting. In this review, we describe the role of the gut microbiome in diabetes patients residing in coastal regions and the underlying mechanisms that existed for analysing and predicting the function of the microbiome in diabetic people. The role of pre, pro, and synbiotics in type 1 and type 2 diabetes are precisely summarized. Keywords: Type 1 diabetes, gut microbiome, type 2 diabetes, coastal region, dysbiosis, prebiotics, synbiotics, probiotics.

Population structure of commercially important groupers in the coral triangle Gorontalo, Indonesia to support conservation

Abstract. Achmad DS, Nurdin MS, Taslim I, Moore AM. 2023. Population structure of commercially important groupers in the coral triangle Gorontalo, Indonesia to support conservation. Biodiversitas 24: 6592-6601. Appropriate management units are fundamental to the conservation of species and ecosystems. In the case of exploited fishes, sustainable approaches to fisheries management are generally based on population units (stocks). This study aimed to address the lack of data to define the population structure of the stocks of two commercially important grouper species (Variola albimarginata (Baissac, 1953) and Variola louti (Forsskål, 1775)) in the Sulawesi Sea and Tomini Bay waters of Gorontalo Province, Sulawesi, Indonesia, in the Wallacea biodiversity hotspot. We used a combined morphometric and molecular (DNA barcoding, COI marker). We used truss network analysis with 14 characters to evaluate inter and intraspecies morphometric differences. DNA was extracted (Qiagen protocols) from tissue samples from individuals of both species in both sea areas, followed by polymerase chain reaction (PCR) and Sanger sequencing. Sequence processing and phylogenetic analyses conducted in MEGA X. Both approaches show clear separation between V. albimarginata and V. louti but indicate close kinship between the north coast (Sulawesi Sea) and south coast (Tomini Bay) populations of these groupers. Under the authority of the Gorontalo Province Marine and Fisheries Service, these two populations could be managed as one stock without compromising fisheries sustainability or the conservation of these ecologically and economically valuable species.

Population structure and connectivity among coastal and freshwater Kelp Gull (Larus dominicanus) populations from Patagonia.

The genetic identification of evolutionary significant units and information on their connectivity can be used to design effective management and conservation plans for species of concern. Despite having high dispersal capacity, several seabird species show population structure due to both abiotic and biotic barriers to gene flow. The Kelp Gull is the most abundant species of gull in the southern hemisphere. In Argentina it reproduces in both marine and freshwater environments, with more than 100,000 breeding pairs following a metapopulation dynamic across 140 colonies in the Atlantic coast of Patagonia. However, little is known about the demography and connectivity of inland populations. We aim to provide information on the connectivity of the largest freshwater colonies (those from Nahuel Huapi Lake) with the closest Pacific and Atlantic populations to evaluate if these freshwater colonies are receiving immigrants from the larger coastal populations. We sampled three geographic regions (Nahuel Huapi Lake and the Atlantic and Pacific coasts) and employed a reduced-representation genomic approach to genotype individuals for single-nucleotide polymorphisms (SNPs). Using clustering and phylogenetic analyses we found three genetic groups, each corresponding to one of our sampled regions. Individuals from marine environments are more closely related to each other than to those from Nahuel Huapi Lake, indicating that the latter population constitutes the first freshwater Kelp Gull colony to be identified as an evolutionary significant unit in Patagonia.

Minerals and fatty acid profile of small indigenous fish species from homestead ponds within a Sub-tropical coastal region

Malnutrition has emerged as a noticeable obstruction to the socio-economic advancement of rural areas along the coastal regions of Bangladesh. Small indigenous fish species (SIS) have the potential to alleviate the malnutrition issue because of having higher nutritional compositions. However, prior research has overlooked the detailed nutritional value of SIS originating from coastal regions. Consequently, the current investigation sought to analyze the mineral and fatty acid composition of twelve SIS obtained from coastal homestead ponds. The findings indicated that the mineral composition in SIS exhibited the following descending order: calcium (Ca) > phosphorus (P) > potassium (K) > magnesium (Mg) > iron (Fe) > zinc (Zn). Furthermore, when considering the overall mineral content in SIS, it ranked in the following decreasing order: A. testudineus, M. tengara, C. punctatus, N. nandus, P. sophore, C. fasciatus, A. mola, C. batrachus, H. fossilis, P. sarana, M. aculeatus, and O. pabda. The analysis of the fatty acid profile further revealed that SIS is a rich source of palmitic acid, linoleic acid, oleic acid, stearic acid, myristic acid, palmitoleic acid, and linolenic acid. The saturated fatty acid content of the SIS varied between 42.66 % and 63.37 %, and the highest content was found in A. mola whereas the lowest was in A. testudineus. On the other hand, the total monounsaturated fatty acid content of the SIS ranged from 26.49 % (A. mola) to 46.12 % (P. sarana), and the total PUFAs contents among the fish species ranged from 5.7 % (A. mola) to 16.54 % (H. fossilis). Therefore, SIS could be a key source of minerals and essential fatty acids for human well-being. This can help fulfill nutrient requirements and reduce malnutrition among coastal populations. It can be said that, if these fishes are introduced in the culture systems, it will be used for consumption as well as support the livelihood of coastal people.

SALTWATER FISH CONSUMPTION AND THE RISK OF STROKE IN COASTAL POPULATION

Indonesia, consisting of tens of thousands of islands, has a rather long coastline with relatively high percentage of it is population that lives in the coastal area. High consumption of saltwater fish in the coastal population is an inevitability. Several studies have observed a relation between saltwater fish consumption and the risk of stroke with contradicting results, protective effect on one side and harmful on the other. The protective effect is mainly mediated by the poly-unsaturated fatty acid (PUFA) content of the saltwater fish while the harmful effect is mediated by the sodium content. PUFA exerts its protective effect through it is antioxidant effect on the endothelial wall, anti-inflammatory effect and the activation of anti-apoptotic pathways in the state of ischemic stroke while sodium increases the risk of hypertension which is the main predisposing factor for stroke and induces anatomical remodeling of the endothelial wall as well as functional abnormalities. Several public health interventions have been carried out to mitigate the harmful effect of the sodium content of saltwater fish yet there hasn’t been a specific intervention for coastal population.

Risk Factors for Cognitive Impairment in Adult Population of Coastal Area: A Cross-Sectional Study in Maringkik Island, Indonesia

Cognitive impairment is a medical condition commonly found in elderly populations, which can be due to vascular risk factors in patients. There remains limited data on risk factors for cognitive impairment among coastal region populations. This study aimed to investigate risk factors for cognitive impairment in the adult population of Maringkik Island, West Nusa Tenggara Province, Indonesia. Data collected were age, sex, education level, hypertension, antihypertensive treatment, diabetes mellitus, cigarette smoking, and body mass index status. A total of 114 participants were recruited using a consecutive sampling method. The participants’ cognitive function assessment used the Mini-Cog instrument. The cognitive impairment frequency in the island’s adult population was approximately 48.2%. The final model of multiple regression analysis showed that hypertension (OR: 2.3; 95%CI: 1.0 – 5.0; p-value: 0.045) was a characteristic associated with the cognitive impairment frequency. Thus, the high frequency of cognitive impairment and hypertension frequency as primary risk factors for cognitive impairment in the island’s adult population implies the need to develop strategies for detecting and managing hypertension and hypertension-related cognitive impairment in the population by local health authorities.

Maritime Environmental Change and its impact on Coastal Bird Diversity

Coastal bird diversity in Indonesia is greatly affected by changes in the maritime environment caused by human activities and climate change. To survive, coastal birds rely heavily on mangrove ecosystems, beaches and estuaries. However, coastal development, land conversion and pollution are damaging these habitats. The purpose of this article is to analyze the impact of changes in the Maritime environment on coastal bird populations and diversity. To achieve this goal, the study used a comprehensive literature approach collected from various related studies, which addressed the effects of changes in the maritime environment on various coastal bird species in Indonesia, such as the Elang laut perut putih, Elang jawa, and Kutul kecil. The results show that such changes are causing bird populations to decline and possibly the extinction of some species, which will ultimately threaten the balance of coastal ecosystems. Based on this article, to protect coastal biodiversity from increasing threats, better conservation and environmental management efforts are needed. Coastal biodiversity conservation strategies should prioritize efforts such as coastal habitat restoration.

Parasites as Indicators of Biotic Interrelations between Fishes and Waterbirds

The paper deals with the structural features of the waterbirds' cenoses, the fish population composition and distribution of metacercariae of trematodes, whose final hosts are waterbirds, in the model shallow lentic ecosystems of the city of Kyiv (Almazne, Martyshev, Verbne lakes and Sovski ponds). The waterbird cenosis was dominated by ichthyophagous (58.5-75.7%) and pantophagous birds (16.4-41.42%). The black-headed gull <i>Chroicocephalus ridibundus</i> (21.9-56.7%) prevailed in terms of relative abundance everywhere. The ornithocenoses differed in terms of the subdominant species: in the Almazne lake it was <i>Podiceps cristatus</i>, in the Martyshev Lake - <i>Sterna hirundo </i>(14.6%), in the Sovski ponds and Verbne Lake - <i>Anas platyrhynchos</i> (12.8-20.2%). Differences in the coastal ornithocenoses' composition were confirmed by results of the cluster analysis WPGMA (weighted pair-group centroid (median)); distance measure - 1-Pearson <i>r</i>). The coastal fish population comprised 24 species, including the native fresh-water (15 species), Ponto-Caspian and Mediterranean self-dispersers (4 species), and alien species - distant invaders (5 species). Parasitological studies revealed trematode metacercariae localized in lens (<i>Diplostomum</i> sp.) and vitreous body (<i>Tylodelphys clavata</i>) of the eye, ripples (<i>Apatemon gracilis</i>), and in the integument of the body (<i>Posthodiplostomum cuticola</i>). The discriminant analysis enabled to reveal significant differences in the species composition and abundance of trematode metacercariae in the water bodies with different structure of the water ornithocenoses (Wilks' Lambda: approx. 0.92235; <i>F</i>(8, 510) = 2.6293f) - 2.6293; the dispersion analysis showed confidently lower total number of trematode metacercariae in the Almazne Lake (Wilks' Lambda = 0.87377; <i>F</i>(6, 432) = 5.0253; <i>p</i><0.00005).

Human activities and sustainability of the sea

The marine system is undergoing profound changes, following global change, rising sea levels as a consequence of rising temperature, significant biogeochemical transformations having multiple impacts in terms of environmental biodiversity and resources. The phenomenon of coastalization represents a fundamental factor of evolution. The coastal population represents more than 60% of the world’s population and continues to grow rapidly through immigration; the population rate expected in 2020 will be 75%. Coastal urbanization is increasing with the creation of coastal mega-cities. This has the consequences of increasing pressure on the coastal terrain and pressure on marine resources. This paper is a short review that reported the danger which face the coastal heritage with a case study on Morocco.

The dilemma of coastal management: Exploitation or conservation?

Abstract The real estate business on sandy coasts and coastal dunes has increased dramatically over the last decades because of the growing demands for leisure activities which, consequently, have yielded important economic gains. Such ravaging exploitation results in the replacement of sandy ecosystems with tourism-oriented settlements, infrastructure, and facilities. As the sandy beaches and coastal dunes become deteriorated or eliminated, their protective role is lost, and the hydrometeorological risks to which the increasing human coastal populations are exposed grow, especially in a climate change scenario with increasing storminess. Furthermore, when possible, the expansion of the tourism industry continues searching for new, unspoiled locations, and the cycle begins again. This situation leads to the dilemma of coastal management: should we continue with the over-exploitation of sandy coasts for growing economic benefits? Or should we preserve the coasts for protection against the impact of increasing storms and sea level rise and to benefit biodiversity? Although scientific evidence demonstrates the relevance of protecting the coasts, coastal development plans continue to ignore these findings. What are the key drivers for these trends? We first looked for scientific evidence of the appraisal of the esthetic beauty of the beach and coastal dunes, as highly important drivers of urbanization and coastal environmental change. We then looked for evidence that demonstrated how coastal dunes offer storm protection Finally, we examined if the conservation of beaches and coastal dunes can be compatible with non-intrusive tourism. In summary, through the literature review and our own data, we show how different alternatives may help achieve a more sustainable coastal tourism by combining economic necessities with environmental concerns.

Global Impact of Sea Level Rise on Coastal Fresh Groundwater Resources

AbstractGroundwater is the main freshwater source in many densely populated and industrialized coastal areas around the world. Growing future freshwater demand is likely to increase the water stress in these coastal areas, possibly leading to groundwater overexploitation and salinization. This situation will likely be aggravated by climate change and the associated projected sea level rise. Here, we assess the impact of sea level rise exclusively on coastal fresh groundwater resources worldwide (limited to areas with unconsolidated sedimentary systems) by estimating future decline in inland fresh groundwater volumes under three sea level rise scenarios following Representative Concentration Pathway (RCP) 2.6, 4.5, and 8.5. For that, 2D groundwater models in 1,200 coastal regions estimate the past, present and future groundwater salinity. Our results show that roughly 60 (range 16–96) million people living within 10 km from current coastline could lose more than 5% of their fresh groundwater resources by 2100 according to RCP 8.5 scenario compared to only 8 (range 0–50) million people based on RCP 2.6 scenario. We conclude that sea level rise will have severe consequences for many coastal populations heavily dependent on fresh groundwater.

Vulnerability, Preparedness, and Previous Experience of Disasters Among the Population of a High Hazard Region-Rural Southern Sindh, Pakistan.

A cross-sectional, mixed-method study was conducted in Badin, a rural area in southern Sindh, which is considered a high-risk disaster zone, to assess the vulnerability, preparedness, and disaster experiences of the coastal population. A multistage sampling technique was employed to select the villages, study area, and 3 distinct populations (I, II, and III). Family heads of households were recruited for population I, village heads for population II, and community support group leaders from selected clusters for population III. The survey was conducted through face-to-face interviews. The results revealed that the population of rural southern Sindh, Pakistan, is highly vulnerable to disasters and exhibits lower levels of preparedness. The statistics about the vulnerable population may prove helpful in designing policies targeting specific groups to mitigate hazards in the future.