23 research outputs found

    Ants as storytellers in Mediterranean riverscapes

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    Doutoramento em Restauro e Gestão Fluviais / Instituto Superior de Agronomia / Faculdade de Arquitectura / Instituto Superior Técnico. Universidade de LisboaRiverscapes support high levels of biodiversity, but are increasingly threatened by global change drivers. Ants are among the most diverse and successful insects on earth and have the ability to respond well to environmental changes. There is a lack of knowledge on the factors that drive ant biodiversity in Mediterranean riverscapes. This thesis aims at studying ant communities in Mediterranean riverscapes, and understand how they respond to disturbance (e.g., land use and invasive species) and to structural attributes of the riverine landscape (e.g., patch typology, spatial configuration and habitat quality), in terms of their richness, abundance and ability to provide ecosystem services. For these purposes, we selected crop and non-crop habitats of the riverine mosaic of three main study areas: a) riparian corridors of Catalonia, Spain; b) riparian corridors and floodplain areas of central Portugal; and c) irrigated cropland of southern Portugal. Ant communities showed to be very sensitive to human-disturbance reflecting a broader perspective of the local ecological status. Based on ants’ responses to different stressors and landscapes elements, we found that land use was the main driver influencing ant communities. However, this might be dependent on the combined factors inherent to the overall disturbance of a particular land use. The Ecological Infrastructure (EI) of less disturbed systems, associated to a reduced abundance of invasive species, showed the highest capacity to provide ant-mediated services. In agricultural areas, ant species are likely recruited from ant communities of the neighbouring EI. Moreover, we found that the Argentine ant may negatively impact native ant communities, particularly in disturbed areas. This thesis has contributed to increment knowledge about ants in riverscapes by providing a biological assessment tool that takes full advantage of ants’ ability to indicate human-disturbance and by providing new insights on the role of EI in ant-diversity conservation in agroecosystems.N/

    Impact of the invasive argentine ant in citrus agroecosystems: effects on the diversity and frequency of native ant species foraging on tree canopy

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    The invasion of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera, Formicidae) can alter the entire ecosystem with serious impacts on the native community structure (e.g., ant diversity) and processes (e.g., trophic interactions) leading to biodiversity loss and pest outbreaks. Most studies addressing these impacts have been conducted in natural or semi-natural areas, few are those conducted in agricultural ecosystems, such as citrus orchards. These are dominant agricultural ecosystems in Mediterranean landscapes. Furthermore, most studies have been conducted in a short span, not evidencing seasonal fluctuations. In this work, we assessed the ecological impact of the Argentine ant on the native ant communities in citrus orchards, in the region of Algarve, southern Portugal. By using principal response curve, we compared seasonal variation on ant assemblages in invaded and uninvaded citrus orchards foraging on tree canopy from a two-year sampling. The Argentine ant had a marked negative impact on the native ant community foraging on citrus canopy. In the uninvaded orchards, the native ant community had a rich assemblage composed of 16 ant species, in its majority (72%) controlled by the dominant species Lasius grandis Forel, Tapinoma nigerrimum (Nylander) and/or Pheidole pallidula (Nylander). In the invaded orchards, the native ant community was poorer and highly modified, mostly dominated by the Argentine ant (80%). Apparently, the only native ant species not a ected by the presence of the Argentine ant was Plagiolepis pygmaea (Latreille). A significant negative e ect was found between the proportion of infested trees by L. humile and the number of native ant species per orchard. Di erences in the native ant community in the invaded and uninvaded orchards persisted over seasons and years. However, negative impacts were higher in the spring and summer, and less pronounced in the autumn. We discuss implications for citrus pest managementinfo:eu-repo/semantics/publishedVersio

    Do dominant native ants outcompete the invasive Argentine ant in Mediterranean citrus ecosystems? A laboratory test

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    The invasive Argentine ant (Linepithema humile) poses a significant threat to ecosystem stability worldwide. In Mediterranean citrus ecosystems, its spread may be limited by interactions with dominant native ant species. We conducted laboratory experiments to investigate the competitive dynamics between Argentine ants and two major native species, Tapinoma nigerrimum and Lasius grandis. At the individual level, both native species exhibited superior competitive performance, attributed to their larger body sizes and potential differences in chemical defences. At the colony level, T. nigerrimum demonstrated efficiency in interference competition, successfully defending food resources from Argentine ants. However, the Argentine ant exhibited higher recruitment capacity, albeit it was density-dependent. Our findings support the hypothesis that dominant native ants can serve as barriers against Argentine ant invasion in citrus ecosystems, highlighting the importance of interspecific competition in shaping community dynamics and invasive species management. This study underscores the potential role of native ant species in mitigating the impacts of invasive ants on ecosystem functioning and biodiversity conservation in agricultural landscapes, offering valuable insights for invasive species management strategies in Mediterranean citrus ecosystemsinfo:eu-repo/semantics/publishedVersio

    Formigas (Hymenoptera, Formicidae) associadas a pomares de citrinos na região do Algarve

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    Mestrado em Engenharia Agronómica - Instituto Superior de AgronomiaAnts (Hymenoptera, Formicidae) may play an important economic role in citrus orchards, either by causing damage in trees or induce pest’s outbreaks, due to interactions with injurious honeydew-producing insects, or even by being potential predators of other arthropods. In order to deepen knowledge about the ant species associated to citrus orchards, in the southern region of Portugal, Algarve, samples were collected in 49 citrus orchards, along the subregions of Litoral, Barrocal and Serra, between July and August 2007. In all, 2812 ants were identified comprising 12 different genera and 26 species. The most common species were Linepithema humile (Mayr), Plagiolepis pygmaea Latreille and Pheidole pallidula (Nylander). Nineteen species are reported for the first time in citrus, in Portugal, and ten are first records, in citrus, in the world. The higher number of species was found in the Serra subregion, with 19 species. Regarding economic importance, special attention must be paid to the phytophagous ants of Tapinoma genus, that can originate direct damage, and the argentine ant, L. humile, which interferes with the activity of natural enemies, disrupting biological control of pests

    Ants (Hymenoptera: Formicidae) and Spiders (Araneae) Co-occurring on the Ground of Vineyards from Douro Demarcated Region

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    This study, held in vineyards from Douro Demarcated Region, aimed to: a) identify the communities and main functional groups of spiders and ants; b) check patterns of co-occurrence between the two communities; and c) evaluate the impact of ground cover and adjacent non-crop habitats in the proximity of vineyards, on the two communities. Samplings were done using pitfall trapping. Twenty species of ants and 44 species of spiders were identified, which included respectively three and nine Iberian endemic species. Aphaenogaster gibbosa (Latreille 1798), Aphaenogaster iberica Emery 1908, Cataglyphis hispanica (Emery 1906), Cataglyphis iberica (Emery 1906), Messor barbarus (L. 1767) and Tapinoma nigerrimum (Nylander 1856) totalized 71.21% of ants. Alopecosa albofasciata (Brullé 1832), Callilepis concolor Simon 1914, Eratigena feminea Simon 1870, Zodarion alacre (Simon 1870) and Zodarion styliferum (Simon 1870) accounted for 38% of spiders. Abundance of both ant-mimicking and ant-eating spiders were positively correlated with Formicinae, while only ant-eating spiders showed positive correlation with Myrmicinae ants. All genera/ species of ant-associated spider were associated with one or more genera/ specie of ants. The abundance of specialist spiders was higher in areas where abundance of ants was also higher. Sheet web weavers spiders were found to be positively correlated with the percentage of ground cover. The present study a) stresses that vineyard agroecosystem support a rich assemblage of ants and spiders evincing that wine production and species conservation is possible and b) the co-occurrence between some species of this two groups is not determined by random patterns

    Ants as bioindicators of riparian ecological health in catalonian rivers

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    In this study, we assess the potential of ants as bioindicators of riparian ecological health in two river types (upland and lowland type) located in the Catalonian region. We proposed to understand to what extent do metrics based on ant responses provide useful information that cannot be presented by traditional biophysical assessments while attempting an approach to creating an ant-based multimetric index (ant-based MMI) of the riparian ecological health. A total of 22 ant species were identified, and 42 metrics related to ant foraging activity, species richness, and functional traits were evaluated as potential core metrics of the index. Riparian features and proximal land use land cover (LULC) were used to distinguish disturbed from less disturbed sites. We found that ant communities strongly responded to human disturbance. When compared with an exclusively physical-based index for the assessment of the riparian health, the ant-based MMI was more sensitive to human disturbance, by also reacting to the effects of the surrounding LULC pressure. This study provides a preliminary approach for an ant-based assessment tool to evaluate the health of riparian corridors although additional research is required to include other river types and a wider stressor gradient before a wider applicationinfo:eu-repo/semantics/publishedVersio

    Soil Arthropods in the Douro Demarcated Region Vineyards : General Characteristics and Ecosystem Services Provided

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    Viticulture is one of the oldest and most profitable forms of agriculture; it is also one of the most intensive farming systems. As intensive cultivation threatens the environment, there is increasing interest in the concept of sustainability within the wine industry, as well as new business opportunities, as customers begin to pay more attention to environmental and sustainability issues. Recognizing the key role of soil quality in environmentally and economically sustainable viticulture makes it essential to understand better soil arthropod communities, given their crucial functions in maintaining soil quality and health. The 'Douro Demarcated Region' (DDR) in northern Portugal offers good potential, in regards to biodiversity, due to its significant areas of non-crop habitats. This work aims to compile information on soil arthropod communities (both soil surface and soil-living) collected in the DDR vineyard agroecosystems. A description of the ecosystem services provided by them, as a basis for the development and implementation of sustainable viticulture systems, is also an objective of this work. An important set of soil arthropods necessary for the delivery of vital ecosystem services for viticulture, with particular reference to supporting and regulating services, occurred in this ecosystem. Eight classes were chiefly represented in a sample of about 167,000 arthropod specimens: Arachnida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca, Pauropoda, and Symphyla. The most representative were Entognatha and Insecta in soil-surface arthropods, and Arachnida and Entognatha in soil-living arthropods. The presence of recognized groups as bioindicators in agroecosystems, such as soil quality indicators, is also revealed. This knowledge is expected to contribute to a more efficient and sustainable management of the viticultural ecosystem.Peer reviewe

    Riparian Ecological Infrastructures: Potential for Biodiversity-Related Ecosystem Services in Mediterranean Human-Dominated Landscapes

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    Riparian Ecological Infrastructures are networks of natural and semi-natural riparian areas located in human-dominated landscapes, crucial in supporting processes that directly or indirectly benefit humans or enhance social welfare. In this study, we developed a novel multimetric index, termed Habitat Ecological Infrastructure’s Diversity Index (HEIDI), to quantify the potential of Riparian Ecological Infrastructures in supporting biodiversity, and related ecosystem services, in three managed landscapes: Intensive Agriculture, Extensive Agriculture, and Forest Production. Metrics describing the structure, composition, and management of riparian vegetation and associated habitats were used to derive the potential of Riparian Ecological Infrastructures in supporting three distinct biological dispersal groups: short-range dispersers (ants), medium-range dispersers (pollinators), and long-range dispersers (birds, bats, and non-flying small mammals). The composition of floristic resources, assessed by identifying trees and shrubs at the species and genus level, and herbaceous plants at the family level, was used as a proxy to evaluate the potential of Riparian Ecological Infrastructures in promoting seed dispersal and pollination ecosystem services provided by the three biological communities. Our research evidenced that Riparian Ecological Infrastructures located in the Forest Production and Intensive Agriculture landscapes exhibited the highest and lowest potential for biodiversity-related ecosystem services, respectively. The Forest Production landscape revealed higher suitability of forage resources for short- and medium-range dispersers and a higher landscape coverage by Riparian Ecological Infrastructures, resulting in more potential to create ecological corridors and to provide ecosystem services. The Riparian Ecological Infrastructures located in the Extensive Agriculture landscape seemed to be particularly relevant for supporting long-ranges dispersers, despite providing less habitat for the biological communities. Land-use systems in the proximity of Riparian Ecological Infrastructures should be sustainably managed to promote riparian vegetation composition and structural quality, as well as the riparian width, safeguarding biodiversity, and the sustainable provision of biodiversity-related ecosystem servicesinfo:eu-repo/semantics/publishedVersio

    An annotated checklist of ladybeetle species (Coleoptera, Coccinellidae) of Portugal, including the Azores and Madeira Archipelagos

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    Research ArticleA comprehensive annotated checklist of the ladybeetle species of Portugal, including the Azores and Madeira archipelagos, is presented. The Coccinellidae fauna comprises a total of 101 species: 83 from the Mainland, 39 from Madeira, and 32 from the Azores. The listed species are distributed among 2 sub-families and 13 tribes: within the subfamily Microweiseinae, Madeirodulini (1 species), Serangiini (2 species), and within the subfamily Coccinellinae, Azyini (1 species), Chilocorini (4 species), Coccidulini (7 species), Coccinellini (30 species), Epilachnini (4 species), Hyperaspidini (7 species), Noviini (2 species), Platynaspini (1 species), Scymnini (37 species), Stethorini (3 species), and Sticholotidini (2 species). The Portuguese fauna comprises 10 exotic species: 5 present in the Mainland, 7 in Madeira, and 6 in the Azores. Harmonia axyridis (Pallas, 1773) from Madeira, Propylea quatuordecimpunctata (Linnaeus, 1758) from the Azores, Delphastus catalinae (Horn, 1895) from the Azores and Madeira, Nephus (Geminosipho) reunioni (Fürsch, 1974) and Nephus (Nephus) voeltzkowi Weise, 1910 from Madeira and Microserangium sp. from the Mainland, are reported for the first time. Some species are considered doubtful records, as explained in the text. These results were obtained by compiling information on the available literature regarding ladybeetle species on the Portuguese mainland and insular territories, and original datainfo:eu-repo/semantics/publishedVersio

    The location and vegetation physiognomy of ecological infrastructures determine bat activity in Mediterranean floodplain landscapes

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    Ecological infrastructures (EI), defined as natural or semi-natural structural elements, are important to support biodiversity and could play a crucial role in counteracting the well-known impacts of intensive agriculture. Yet, the importance of EI remains largely unexplored in Mediterranean agricultural landscapes and for species providing essential ecosystem services such as bats. Here, we evaluated the role of different EI types – in terms of location (riparian vs terrestrial) and vegetation physiognomy (woody vs non-woody) – in shaping bat guild activity in crop fields located in the floodplains of the Iberian Peninsula. We recorded 60,732 bat sequences in 96 crop fields and characterised 106 EI patches via an adaptation of the Biodiversity Potential Index (BPI). We found that the activity of mid-range echolocators (MRE) and long-range echolocators (LRE) was twofold higher when the nearest EI patch was riparian (i.e., contiguous to a watercourse) than when it was terrestrial. When assessing changes in bat activity in crop fields in relation to a gradient distance from EI types, our results revealed both distinct and similar effects of the location and vegetation physiognomy of the EI on bat guilds. For instance, while only the LRE guild positively responded to the proximity of woody EI, both MRE and LRE showed a marked increase of activity when increasing distances to non-woody EI, thus suggesting low bat activity levels near these features. Our habitat quality assessment also revealed that woody EI and riparian EI had higher biodiversity potential and related habitat quality, thus contributing to our understanding of bat responses to EI type in crop fields. As riparian areas are rarely targeted in biodiversity-friendly measures in farmland, we strongly recommend including riparian EI (especially the woody type) in conservation planning as they are crucial for both biodiversity conservation and ecosystem functioning
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