562 research outputs found

    Tournaisian (Mississippian) brachiopods from the Mobarak Formation, North Iran

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    Following detailed stratigraphic work on the Mississippian marlstone and bioclastic limestone of the Mobarak Formation of the Alborz Mountains in North Iran, forty-eight of the most important brachiopod taxa are here systematically described and illustrated. The ranges of the taxa are given along the Abrendan and Simeh Kuh stratigraphic sections, located north of Damgham. The examined brachiopod species date the base of the Mobarak Formation to the Tournaisian, in absence of age-diagnostic foraminifers. Change in brachiopod settling preferences indicates a shift from high energy, shallow-water settings with high nutrient supply in the lower part of the formation to quieter, soft, but not soppy substrates, with lower nutrient supply in the middle part of the Mobarak Formation. Brachiopod occurrence is instead scanty at its top. The palaeobiogeographic affinity of the Tournaisian brachiopods from North Iran indicates a closer relationship to North America, Western Europe and the Russian Platform than to cold-water Australian faunas, confirming the affinity of the other biota of the Alborz Mountains. This can be explained by the occurrence of warm surface-current gyres widely distributing brachiopod larvae across the Palaeotethys Ocean, where North Iran as other peri-Gondwanan blocks acted as staging-posts

    New records and new taxa of Permian brachiopods from the Khuff Formation, Midhnab Member, central Saudi Arabia

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    Brachiopods are described for the first time from outcrops of the lower part of the Midhnab Member of the Khuff Formation in central Saudi Arabia. The very rare fauna discovered includes Kotlaia sp. ind. of the order Orthida and Omanilasma husseinii n. gen. n. sp. of the order Terebratulida. Besides this new taxon, another new species Omanilasma desertica n. gen. n. sp. from the Khuff Formation of Interior Oman is here erected. The brachiopods were collected from an open-marine horizon and are associated with nautiloids, bactritids, bivalves, foraminifers, algae, and ostracods. A probable Late Permian age is assigned to the lower part of the Midhnab Member based on foraminifers. The brachiopods are compared to similar faunas from the Middle Permian Khuff Formation of Interior Oman, Amb Formation of Salt Range (Pakistan) and Rat Buri Limestone of Southeast Thailand

    Fine-scale fern ecological responses inform on riparian forest habitat conservation status

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    The recognition of the ecological quality of ecosystems and habitats therein is increasingly important in the Anthropocene. However, there are still scarcely explored ways of how and what to assess to obtain a sound ecological status of habitats. Ferns are an understudied plant group, especially given their usefulness as ecological indicators. Disentangling biotic and abiotic factors that drive fine-scale fern distribution could provide insight into the quality of their habitats. We investigated the environmental factors affecting the distribution of different largely distributed fern species in Europe. We studied their presence and abundance at different life stages in a forest habitat of European priority conservation concern. Our aim was to understand whether fern species can be used as an ecological indicator group in riparian alderwood habitat. We sampled 120 plots of 50 m(2) in randomly selected transects along streams of a riparian forest habitat characterized by the presence of many fern species in the understory, controlling for the effects of geology and elevation. Within each plot, fern species were recorded, including vegetative and generative stages of each ramet (rosette of fronds). We modelled fern occurrence and abundance for the different fern life stages, and diversity indices of the fern community in relation to environmental predictors. We found that population- and community-level responses of ferns mainly depended on soil granulometry and, to a lesser extent, moss cover and stream orientation. We also found that the generative life stage compared to the vegetative adult stage benefits from different ecological characteristics for certain fern species. Alterations of the natural hydrology might lead to a general deterioration in habitat quality for ferns. We suggest that some fern species acting as early-warning species, and potentially their life stages, can be used as an ecological quality indicator for riparian forest habitats. This study deepened the understanding of the fine-scale ecology of an array of European ferns in riparian forests and provides valuable information to assist in the conservation of fern species and their populations

    Sedimentary context and palaeoecology of Gigantoproductus shell beds in the Mississippian Eyam Limestone Formation, Derbyshire carbonate platform, central England

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    A sedimentological study was conducted at two localities exposing the Mississippian Eyam Limestone Formation of the Derbyshire carbonate platform, UK. Ricklow Quarry comprises seven facies with diverse skeletal assemblages, representing deposition on the inner to middle ramp within open marine waters. Once-a-Week Quarry comprises four facies, dominated by crinoidal debris representing deposition on the inner ramp. Both localities expose Gigantoproductus shell beds. Palaeoecological analysis of a single shell bed from each locality enabled investigation of the rapid colonization and success of this taxon on the platform. At Ricklow Quarry, on the eastern side of a localized mud mound, both life (>72% of thin and thick-shelled brachiopods in life position) and neighbourhood assemblages are present. A low-moderate diversity community (<1.37 and <0.8 Shannon diversity index) rapidly established over relict Brigantian mud mounds. Shell beds are preluded by intervals of decreased energy that allowed larvae to settle. Once established, the dominance of thick-shelled individuals enabled baffling, potentially providing localized shelter for larvae and nearby individuals. At Once-a-Week Quarry, where no mud mound is present, only thick-shelled Gigantoproductus species and a low diversity community (<1.07 Shannon diversity index) exclusively comprising neighbourhood assemblages (37% in life position) is present. The presence of inactive mud mounds at Ricklow Quarry appears to have been the key to the success of Gigantoproductus species enabling the onset of stable communities in the shelter provided by the relict mound. Once the first palaeocommunities were established, larvae dispersed and colonized higher energy settings, such as at Once-a-Week Quarry

    Robotic Monitoring of Habitats: the Natural Intelligence Approach

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    In this paper, we first discuss the challenges related to habitat monitoring and review possible robotic solutions. Then, we propose a framework to perform terrestrial habitat monitoring exploiting the mobility of legged robotic systems. The idea is to provide the robot with the Natural Intelligence introduced as the combination of the environment in which it moves, the intelligence embedded in the design of its body, and the algorithms composing its mind. This approach aims to solve the challenges of deploying robots in real natural environments, such as irregular and rough terrains, long-lasting operations, and unexpected collisions, with the final objective of assisting humans in assessing the habitat conservation status. Finally, we present examples of robotic monitoring of habitats in four different environments: forests, grasslands, dunes, and screes
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