New Genetic and Linguistic Analyses Show Ancient Human Influence on Baobab Evolution and Distribution in Australia

This study investigates the role of human agency in the gene flow and geographical distribution of the Australian baobab, Adansonia gregorii. The genus Adansonia is a charismatic tree endemic to Africa, Madagascar, and northwest Australia that has long been valued by humans for its multiple uses. The distribution of genetic variation in baobabs in Africa has been partially attributed to human-mediated dispersal over millennia, but this relationship has never been investigated for the Australian species. We combined genetic and linguistic data to analyse geographic patterns of gene flow and movement of word-forms for A. gregorii in the Aboriginal languages of northwest Australia. Comprehensive assessment of genetic diversity showed weak geographic structure and high gene flow. Of potential dispersal vectors, humans were identified as most likely to have enabled gene flow across biogeographic barriers in northwest Australia. Genetic-linguistic analysis demonstrated congruence of gene flow patterns and directional movement of Aboriginal loanwords for A. gregorii. These findings, along with previous archaeobotanical evidence from the Late Pleistocene and Holocene, suggest that ancient humans significantly influenced the geographic distribution of Adansonia in northwest Australia.

Detection and attribution of human influence on regional precipitation

Understanding how human influence on climate is affecting precipitation around the world is immensely important for defining mitigation policies, and for adaptation planning. Yet despite increasing evidence for the influence of climate change on global patterns of precipitation, and expectations that significant changes in regional precipitation should have already occurred as a result of human influence on climate, compelling evidence of anthropogenic fingerprints on regional precipitation is obscured by observational and modelling uncertainties and is likely to remain so using current methods for years to come. This is in spite of substantial ongoing improvements in models, new reanalyses and a satellite record that spans over thirty years. If we are to quantify how human-induced climate change is affecting the regional water cycle, we need to consider novel ways of identifying the effects of natural and anthropogenic influences on precipitation that take full advantage of our physical expectations.

Influence of Increased Human Presence in the Mills River Basin on Water Availability and Drought

Periods of drought and low streamflow can have profound impacts on both human and natural systems. People depend on a reliable source of water for numerous reasons including potable water supply and to produce economic value through agriculture or energy production. Aquatic ecosystems depend on water in addition to the economic benefits they provide to society through ecosystem services. Given that periods of low streamflow may become more extreme and frequent in the future, it is important to study the factors that control water availability during these times. In the absence of precipitation the slower hydrological response of groundwater systems will play an amplified role in water supply. Understanding the variability of the fraction of streamflow contribution from baseflow or groundwater during periods of drought provides insight into what future water availability may look like and how it can best be managed. The Mills River Basin in North Carolina is chosen as a case-study to test this understanding. First, obtaining a physically meaningful estimation of baseflow from USGS streamflow data via computerized hydrograph analysis techniques is carried out. Then applying a method of time series analysis including wavelet analysis can highlight signals of non-stationarity and evaluate the changes in variance required to better understand the natural variability of baseflow and low flows. In addition to natural variability, human influence must be taken into account in order to accurately assess how the combined system reacts to periods of low flow. Defining a combined demand that consists of both natural and human demand allows us to be more rigorous in assessing the level of sustainable use of a shared resource, in this case water. The analysis of baseflow variability can differ based on regional location and local hydrogeology, but it was found that baseflow varies from multiyear scales such as those associated with ENSO (3.5, 7 years) up to multi decadal time scales, but with most of the contributing variance coming from decadal or multiyear scales. It was also found that the behavior of baseflow and subsequently water availability depends a great deal on overall precipitation, the tracks of hurricanes or tropical storms and associated climate indices, as well as physiography and hydrogeology. Evaluating and utilizing the Duke Combined Hydrology Model (DCHM), reasonably accurate estimates of streamflow during periods of low flow were obtained in part due to the model’s ability to capture subsurface processes. Being able to accurately simulate streamflow levels and subsurface interactions during periods of drought can be very valuable to water suppliers, decision makers, and ultimately impact citizens. Knowledge of future droughts and periods of low flow in addition to tracking customer demand will allow for better management practices on the part of water suppliers such as knowing when they should withdraw more water during a surplus so that the level of stress on the system is minimized when there is not ample water supply.

Human impacts and aridity differentially alter soil N availability in drylands worldwide

Aims Climate and human impacts are changing the nitrogen (N) inputs and losses in terrestrial ecosystems. However, it is largely unknown how these two major drivers of global change will simultaneously influence the N cycle in drylands, the largest terrestrial biome on the planet. We conducted a global observational study to evaluate how aridity and human impacts, together with biotic and abiotic factors, affect key soil variables of the N cycle. Location Two hundred and twenty-four dryland sites from all continents except Antarctica widely differing in their environmental conditions and human influence. Methods Using a standardized field survey, we measured aridity, human impacts (i.e. proxies of land uses and air pollution), key biophysical variables (i.e. soil pH and texture and total plant cover) and six important variables related to N cycling in soils: total N, organic N, ammonium, nitrate, dissolved organic:inorganic N and N mineralization rates. We used structural equation modelling to assess the direct and indirect effects of aridity, human impacts and key biophysical variables on the N cycle. Results Human impacts increased the concentration of total N, while aridity reduced it. The effects of aridity and human impacts on the N cycle were spatially disconnected, which may favour scarcity of N in the most arid areas and promote its accumulation in the least arid areas. Main conclusions We found that increasing aridity and anthropogenic pressure are spatially disconnected in drylands. This implies that while places with low aridity and high human impact accumulate N, most arid sites with the lowest human impacts lose N. Our analyses also provide evidence that both increasing aridity and human impacts may enhance the relative dominance of inorganic N in dryland soils, having a negative impact on key functions and services provided by these ecosystems.

Spatial, environmental and human influences on the distribution of otter (Lutra lutra) in the Spanish provinces

In a previous survey of otters ( Lutra lutra L. 1758) in Spain, different causes were invoked to explain the frequency of the species in each province. To find common causes of the distribution of the otter in Spain, we recorded a number of spatial, environmental and human variables in each Spanish province. We then performed a stepwise linear multiple regression of the proportion of positive sites of otter in the Spanish provinces separately on each of the three groups of variables. Geographic longitude, January air humidity, soil permeability and highway density were the variables selected. A linear regression of the proportion of otter presence on these variables explained 62.4% of the variance. We then used the selected variables in a partial regression analysis to specify which proportions of the variation are explained exclusively by spatial, environmental and human factors, and which proportions are attributable to interactions between these components. Pure environmental effects accounted for only 5.5% of the variation, while pure spatial and pure human effects explained 18% and 9.7%, respectively. Shared variation among the components totalled 29.2%, of which 10.9% was explained by the interaction between environmental and spatial factors. Human factors explained globally less variance than spatial and environmental ones, but the pure human influence was higher than the pure environmental one. We concluded that most of the variation in the proportion of occurrences of otter in Spanish provinces is spatially structured, and that environmental factors have more influence on otter presence than human ones; however, the human influence on otter distribution is less structured in space, and thus can be more disruptive. This effect of large infrastructures on wild populations must be taken into account when planning large-scale conservation policies

Ciclo testicular e espermatogênese de Devario aequipinnatus (cypriniformes, cyprinidae) submetido a diferentes temperaturas

Pós-graduação em Ciência e Tecnologia Animal - FEIS

A comparison of bryophyte diversity in the Macaronesian Islands: island versus habitat approach

In this paper, we present a comparison of richness patterns and floristic similarity for bryophytes in the five most important altitudinal habitat types in the Macaronesian islands. We evaluate the importance of different factors discussed in the literature in predicting species diversity applying the traditional island approach and within the framework of the new habitat approach, including area, isolation, climatic factors, geological age and human influence. From the analysis of patterns of bryophyte species distribution for selected habitats across islands and archipelagos, we specifically test the hypothesis that (i) floristic similarity is primarily determined by climatic factors, but not by geographical distance due to high dispersal ability in this species group and (ii) bryophyte richness is best predicted by area, but not by geological age of the habitat due to very low endemicity or speciation rate and high colonization rate.

Caraterização dos habitats propícios à conservação da Estrelinha-de-Santa-Maria (Regulus regulus sanctaemariae)

Dissertação de Mestrado, Gestão e Conservação da Natureza, 11 de Junho de 2014, Universidade dos Açores.

Taxonomy, distribution and population structure of invasive Corbiculidae (Mollusca, Bivalvia) in the Suquía River basin, Córdoba, Argentina

Invasive species are one of the most significant causes of biodiversity loss and changes in ecosystem services, which underlines the importance of their detection and their study. The Asian clams (Corbiculidae) are invasive organisms that accidentally entered the La Plata River, Argentina, presumably in the 1960s. The objectives of the present study were to identify the corbiculid species and to determine their distribution at several locations along the Suquía River basin, an extended area in central Argentina. In addition, population structure was evaluated monthly during one year, at a site in the city of Córdoba that is characterized by high human influence. The presence of Corbicula fluminea (Müller, 1774) and Corbicula largillierti (Philippi, 1844) in the Suquía River basin is reported for the first time. The former species was found only in a lentic environment (San Roque reservoir), while the latter was also found along the tributary rivers and brooks of the basin. Corbicula largillierti showed variations in average density between the different sites and also in biomass and size classes throughout the study period at the site at Córdoba city. The relative composition of the sediments, flow fluctuation and human pollution may be responsible for the observed differences.

Balloniscus glaber (Crustacea, Isopoda, Balloniscidae), a habitat specialist species in a disturbed area of Brazil

ABSTRACT Balloniscus glaber Araujo & Zardo, 1995 (Balloniscidae), a Neotropical Oniscidea, has been recorded historically in environments with low or no human interference. In one of these areas, it was determined as aK-strategist. Recently, however, this species was documented in a disturbed forest within urban limits. The present work revealed that the population in the urban area has high density, high number of ovigerous females and mancae in the population, a long reproductive period, and early sexual maturity. These results suggest that modified environments may provide favorable conditions and that the species is not negatively affected by human influence.

Indicator taxa of benthic diatom communities: a case study in Mediterranean streams

A key issue in the implementation of the Water Framework Directive is the classification of streams and rivers using biological quality parameters and type-specific reference conditions. Four groups of stream types were defined in NE Spain on the basis of 152 diatom samples by means of detrended correspondence analysis and classification techniques. Diatom analysis was restricted to epilithic taxa, and the sites included gradients ranging from near-natural streams to sites with poor ecological quality. The main gradient shows a clear separation of sites in relation to the degree of human influence: polluted streams (mainly located in the lowlands) differ from streams in mountainous areas and in the Pyrenees. A second gradient is related to physiographical features. Headwater streams can be distinguished by their catchment geology. The type-specific diatom taxa for the stream types studied were determined by using indicator species analysis (IndVal). The type-specific taxa from near-natural streams are coincident with the indicator taxa for high ecological status. Human impact reduced the typological heterogeneity of the diatom community composition. Overall, the diatom communities in NE Spain exhibit a regional distribution pattern that closely corresponds with that observed in river systems elsewhere. Physiographical differences are only evident in undisturbed sites, while nutrient enrichment and other human disturbances may mask the regional differences in the distribution of diatom communities

Avaliação Ecológica das Terras Salgadas - Ilha do Maio, Cabo Verde para Possível Estabelecimento de uma Nova População da Laverca do Raso (Alauda Razae)

A laverca do Raso (Alauda razae) é uma espécie em risco crítico de extinção pois só existe num pequeno ilhéu de 7km2, o ilhéu do Raso em Cabo Verde. As medidas de protecção já adoptadas, não são, aparentemente, suficientes para prevenir os riscos a que esta espécie está ou poderá estar sujeita e que podem incluir grandes períodos de seca, ocorrência de uma catástrofe natural ou a introdução acidental de mamíferos predadores, como gatos e ratos. Assim, torna-se urgente a adopção de outras medidas de protecção da espécie, como por exemplo o estabelecimento de novas populações noutras ilhas. A ilha do Maio, localizada no grupo sul do arquipélago de Cabo Verde, a 200km do Raso, poderá ser um bom local para estabelecer uma nova população da laverca do Raso. A zona litoral das Terras Salgadas é um local potencial para este efeito, uma vez que é um Parque Nacional, protegido por lei e apresenta um habitat potencialmente semelhante ao encontrado no Ilhéu do Raso. No presente estudo procedeu-se à avaliação ecológica das Terras Salgadas de modo a avaliar a possibilidade de aí se estabelecer uma nova população da laverca do Raso. Foram selecionadas 4 áreas litorais (cada uma com 25ha) que foram caracterizadas quanto ao tipo de ocupação do solo, à flora e à fauna, através de pontos de amostragem, transectos lineares, captura de ratos e contagem de insectos nocturnos. Foi dada particular atenção aos factores favoráveis à sobrevivência da cotovia-do-Raso (presença de plantas e insectos de que se alimenta e de locais favoráveis à nidificação) bem como àqueles que constituem riscos (influência humana e presença de predadores). Todos estes dados foram georreferenciados e mapeados. Os resultados obtidos permitiram concluir que, apesar da existência de factores de risco para a introdução da laverca do Raso, existem pelo menos duas áreas estudadas que reúnem as condições potencialmente adequadas ao estabelecimento bem-sucedido de uma nova população desta espécie.