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Understanding the dynamics of population recovery in threatened species requires robust longitudinal monitoring datasets. However, evidence-based decision-making is often impeded by variable data collection approaches, necessitating critical evaluation of restricted available baselines. The Hainan gibbon, the world's rarest primate, had possibly declined to only seven or eight individuals in 1978 at Bawangling National Nature Reserve but has experienced subsequent population growth. Past population estimates lack detailed reporting of survey effort, and multiple conflicting estimates are available, hindering assessment of gibbon recovery. We investigated all reported estimates of Bawangling gibbon population size from 1978 to 2022, to evaluate the biological signal of population trends and the extent to which noise associated with varying survey effort, reporting and estimation may mask or misrepresent any underlying signal. This longitudinal dataset demonstrates that the Bawangling population experienced a series of bottlenecks and recoveries, with three successive periods of growth interspersed by population crashes (1978-1989, 1989-2000 and 2000-2022). The rate of gibbon population recovery was progressively slower over time in each successive period of growth, and this potential decline in recovery rate following serial bottlenecks suggests that additional management strategies may be required alongside "nature-based solutions" for this species. However, population viability analysis suggests the 1978 founder population is unlikely to have been as low as seven individuals, raising concerns for interpreting reported historical population counts and understanding the dynamics of the species' recovery. We caution against overinterpreting potential signals within "messy" conservation datasets, and we emphasise the crucial importance of standardised replicable survey methods and transparent reporting of data and effort in all future surveys of Hainan gibbons and other highly threatened species.
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BACKGROUND: A major goal in evolutionary biology is to understand the processes underlying phenotypic variation in nature. Commonly, studies have focused on large interconnected populations or populations found along strong environmental gradients. However, studies on small fragmented populations can give strong insight into evolutionary processes in relation to discrete ecological factors. Evolution in small populations is believed to be dominated by stochastic processes, but recent work shows that small populations can also display adaptive phenotypic variation, through for example plasticity and rapid adaptive evolution. Such evolution takes place even though there are strong signs of historical bottlenecks and genetic drift. Here we studied 24 small populations of the freshwater fish Arctic charr (Salvelinus alpinus) found in groundwater filled lava caves. Those populations were found within a few km2-area with no apparent water connections between them. We studied the relative contribution of neutral versus non-neutral evolutionary processes in shaping phenotypic divergence, by contrasting patterns of phenotypic and neutral genetic divergence across populations in relation to environmental measurements. This allowed us to model the proportion of phenotypic variance explained by the environment, taking in to account the observed neutral genetic structure. RESULTS: These populations originated from the nearby Lake Mývatn, and showed small population sizes with low genetic diversity. Phenotypic variation was mostly correlated with neutral genetic diversity with only a small environmental effect. CONCLUSIONS: Phenotypic diversity in these cave populations appears to be largely the product of neutral processes, fitting the classical evolutionary expectations. However, the fact that neutral processes did not explain fully the phenotypic patterns suggests that further studies can increase our understanding on how neutral evolutionary processes can interact with other forces of selection at early stages of divergence. The accessibility of these populations has provided the opportunity for long-term monitoring of individual fish, allowing tracking how the environment can influence phenotypic and genetic divergence for shaping and maintaining diversity in small populations. Such studies are important, especially in freshwater, as habitat alteration is commonly breaking populations into smaller units, which may or may not be viable.
Asunto(s)
Ecosistema , Flujo Genético , Animales , Trucha/genéticaRESUMEN
Many techniques have been studied for recovering information from shared media such as optical fiber that carries different types of communication, sensing, and data streaming. This article focuses on a simple method for retrieving the targeted information with the least necessary number of significant samples when using statistical population sampling. Here, the focus is on the statistical denoising and detection of the fiber Bragg grating (FBG) power spectra. The impact of the two-sided and one-sided sliding window technique is investigated. The size of the window is varied up to one-half of the symmetrical FBG power spectra bandwidth. Both, two- and one-sided small population sampling techniques were experimentally investigated. We found that the shorter sliding window delivered less processing latency, which would benefit real-time applications. The calculated detection thresholds were used for in-depth analysis of the data we obtained. It was found that the normality three-sigma rule does not need to be followed when a small population sampling is used. Experimental demonstrations and analyses also showed that novel denoising and statistical threshold detection do not depend on prior knowledge of the probability distribution functions that describe the FBG power spectra peaks and background noise. We have demonstrated that the detection thresholds' adaptability strongly depends on the mean and standard deviation values of the small population sampling.
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RESUMO No Brasil, os impactos socioambientais da crise hídrica são intensificados uma vez que a drenagem e o manejo das águas pluviais são marcados por ausências e limitações de políticas públicas. O saneamento básico é de titularidade municipal e, para o exercício desse direito e dever, é fundamental que os municípios estruturem a política municipal, sendo o planejamento seu principal instrumento. Nesse contexto, buscou-se neste artigo identificar e analisar o panorama da elaboração de Planos Municipais de Saneamento Básico e de Planos Diretores de Drenagem Urbana nos municípios do estado de Minas Gerais com população inferior a 50 mil habitantes e comparar esses resultados com as informações divulgadas pelo Sistema Nacional de Informações sobre Saneamento no ano de 2019. Realizaram-se buscas na internet e contatos com os municípios, por telefone, e foi possível identificar que, entre os 752 municípios de Minas Gerais de pequeno porte, 499 possuem Planos Municipais de Saneamento Básico, enquanto nenhum possui Planos Diretores de Drenagem Urbana. Ao comparar esses resultados com as informações divulgadas pelo Sistema Nacional de Informações sobre Saneamento, observou-se que 79 municípios prestaram informações inconsistentes relacionadas à existência de Planos Municipais de Saneamento Básico e 48 afirmaram possuir Planos Diretores de Drenagem Urbana. Conclui-se que muitos municípios mineiros ainda não possuem Planos Municipais de Saneamento Básico, e que o processo de coleta dos dados do Sistema Nacional de Informações sobre Saneamento precisa ser aprimorado para que haja melhor qualidade dos dados divulgados. A ausência de instrumentos de planejamento que auxiliem a efetivação da política municipal é um importante problema a ser superado para o enfrentamento dos complexos desafios que envolvem a drenagem e o manejo das águas pluviais municipal.
ABSTRACT In Brazil, the impacts of the water crisis are intensified since the Drainage and Rainwater Management are marked by absences and limitations of public policies. Basic sanitation is a municipal property and for the exercise of this right and duty, it is essential that the municipalities structure the municipal policy, with planning as their main instrument. In this context, this article aimed to identify and analyze the panorama of the elaboration of Municipal Basic Sanitation Plans and Master Plans for Urban Drainage in the municipalities of the state of Minas Gerais with a population of less than 50,000 inhabitants and to compare these results with the information released by the National Sanitation Information System, in 2019. Internet searches and contacts with the municipalities were carried out by telephone, so that it was possible to identify that among the 752 small-sized ones in Minas Gerais, 499 of them have Municipal Basic Sanitation Plans, while none of them have Master Plans for Urban Drainage. When comparing these results with the information released by the National Sanitation Information System, it was observed that 79 municipalities provided inconsistent information related to the existence of Municipal Basic Sanitation Plans and 48 municipalities claimed to have Master Plans for Urban Drainage. It is concluded that many municipalities in Minas Gerais do not yet have Municipal Basic Sanitation Plans and that the process of collecting National Sanitation Information System data needs to be improved so that there is a better quality of the data released. The absence of planning instruments to assist the implementation of municipal policy is an important problem to be overcome in order to face the complex challenges involving municipal Stormwater Drainage and Management.