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Ecological Infrastructures (EIs) form a network of natural and semi-natural areas crucial to support biodiversity in human-altered landscapes. Several indices have been proposed to assess the ecological quality of EIs, but these have been seldom tested using animal biodiversity as a response variable. The Habitat Ecological Infrastructure's Diversity Index (HEIDI) was recently developed to assess the potential of EIs in supporting biological communities with distinct dispersal abilities. In this study, we evaluated the strength of the HEIDI as a proxy of ant (short-range dispersers) and bat (long-range dispersers) activity in two Mediterranean agricultural areas. For this, we applied a Hierarchical Modelling of Species Communities (HMSC) approach and modelled the multispecific response of ant and bat communities to the HEIDI values and to the scores of the individual categories that compose it. We additionally adopted a functional methodological approach by selecting as response variables the activity of functional guilds, namely animal community regulators, decomposers, and seed dispersers for the ant community, and the activity of echolocation guilds, such as short-range (BAT_SRE), mid-range (BAT_MRE), and long-range echolocators (BAT_LRE) for the bat community. Besides the HEIDI, we also used physiognomic and structural EI attributes, as well as the percentage of the agricultural matrix in the ecological area of influence as covariates in the HMSC approach. Our results showed that the HEIDI formula was particularly accurate in predicting bat activity (posterior mean estimates, βBAT_SRE = 2.80, βBAT_MRE = 0.61, βBAT_LRE = 2.76), but no significant relation was found between HEIDI values and ant activity. In the context of Mediterranean floodplain management, we recommend that practitioners may use the individual HEIDI categorical scores to identify key habitat features that promote ant and bat activity, such as vegetation and aquatic habitats, whilst final HEIDI values may be broadly used to estimate global bat activity.

The Riparian Ecological Infrastructure (REI) is defined by the ensemble of natural and semi-natural woody and herbaceous vegetation patches located contiguously to water courses. Freshwater environments and the associated REI provide habitat for many species, acting as corridors linking landscapes at a wider scale.Focusing on ants, a ubiquitous and diverse group of insects that provide a large number of ecosystem roles, we address the relative importance of REI-related local and landscape factors that drive the species and functional richness of ant communities.The study was conducted in 2019, at 100 sites in central Portugal, in Tagus and Sorraia irrigated valleys, comprising three landscape systems, namely, Forest production, Agroforestry and Irrigated cropland. Four major types of variables were used to characterize the sampling patches, including the landscape system, patch typology, spatial configuration and habitat quality. Ants were collected using pitfall traps and species composition was used to classify functional groups. Using an extensive survey, machine learning methods were used to identify the relative importance of REI-related variables in explaining ant specific and functional richness.Results indicated that ant biodiversity was primarily explained by the ‘Landscape system’ and the ‘Argentine ant abundance’. Nevertheless, ‘Shrub richness’ was selected as an important variable to enhance ‘Animal community regulation’ and ‘Plant community regulation’ functional groups, while herbaceous patches appeared to be relevant for the ‘Decomposition through scavenging’ group.The highest ant biodiversity was found in the Forest production ‘Landscape system’, where patches were larger, more complex and less fragmented, showing high habitat quality associated with a reduced abundance of the invasive Argentine ant. Contrarily, the lowest was expected in the Intensive cropland ‘Landscape system’, where the REI is highly fragmented, showing low habitat quality and suffering from a high Argentine ant invasion, as a result of high human pressure. The Agroforestry ‘Landscape system’ showed moderate ant biodiversity, mainly associated with patches characterized by low strata complexity and shrub cover densities, due to understory clearing and grazing activities.

Cities, due to the presence of ports and airports and the high diversity of trees in streets, parks, and gardens, may play an important role for the introduction of invasive forest pests. We hypothesize that areas of urban forest facilitate the establishment of non-native forest pests. Based on scientific literature and a pan-European database on non-native species feeding on woody plants, we analysed where the first detections occurred in European countries. We collected site data for 137 first detections in Europe and 508 first European country-specific records. We also estimated the percentage of tree cover and suitable habitat (green areas with trees) in buffers around detection points. The large majority of first records (89% for first record in Europe and 88% for first records in a European country) were found in cities or suburban areas. Only 7% of the cases were in forests far from cities. The probability of occurrence decreased sharply with distance from the city. The probability to be detected in urban areas was higher for sap feeders, gall makers, and seed or fruit feeders (>90%) than for bark and wood borers (81%). Detection sites in cities were highly diverse, including public parks, street trees, university campus, arboreta, zoos, and botanical gardens. The average proportion of suitable habitat was less than 10% in urban areas where the species were detected. Further, more than 72% of the cases occurred in sites with less than 20% of tree cover. Hotspots of first detection were identified along the coastal regions of the Mediterranean and Atlantic, and near industrial areas of central Europe. We conclude that urban trees are main facilitators for the establishment of non-native forest pests, and that cities should thus be intensely surveyed. Moreover, as urban areas are highly populated, the involvement of citizens is highly recommended.

We aimed at assessing the role of ecological infrastructures (EI) in promoting ant biodiversity in floodplain Mediterranean agricultural crops. We examined and compared ant communities at the interface between EI (remnant vegetation patches) and adjoining agricultural matrix (maize, rice, others) in irrigated farmland. The study was conducted in 2019, in two agricultural landscapes in the valleys of the rivers Tagus and Sorraia, Central Portugal. We used the Akaike information criterion for model selection and to distinguish among a set of possible models describing the relationship between: the ant richness in the agricultural matrix and drivers associated with the surrounding landscape and crop type; the ant richness in EI and the habitat quality of EI patches, the characteristics of the surrounding landscape, and the presence of invasive ant species. We found that: EI patches supported a higher ant diversity and an overall specialized ant community, distinctive from the agricultural matrix; location but not vegetation physiognomy influenced ant diversity; ant richness within the agricultural matrix decreased with the distance to the EI, and that this relationship was influenced by the crop type; and that ant richness in the EI was associated with the absence of the invasive Argentine ant and the area of terrestrial EI in the surrounding landscape.

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 application.

The connectivity of riparian forests can be used as a proxy for the capacity of riparian zones to provide ecological functions, goods and services. In this study, we aim to test the potential of the freely available Copernicus “Riparian Zones” dataset to characterize the connectivity of riparian forests located in two European bioclimatic regions—the Mediterranean and the Central Baltic hydroregions—when subject to a gradient of human disturbance characterized by land-use/land-cover and hydromorphological pressures. We extracted riparian patches using the Copernicus “Actual Riparian Zone” (ARZ) layer and calculated connectivity using the Integral Index of Connectivity (IIC). We then compared the results with a “Manual Riparian Zone” (MRZ) layer, produced by manually digitizing riparian vegetation patches over a very high-resolution World Imagery layer. Our research evidenced reduced forest connectivity in both hydroregions, with the exception of Least Disturbed sites in the Central Baltic hydroregion. The ARZ layer exhibited overall suitability to assess the connectivity of riparian forests in the Central Baltic hydroregion, while the Mediterranean hydroregion displayed a consistent pattern of connectivity overestimation in all levels of human disturbance. To address this, we recommend some improvements in the spatial resolution and thematic accuracy of the Copernicus ARZ layer.

This study aims to estimate the total biomass aboveground and soil carbon stocks in a Mediterranean riparian forest and identify the contribution of the different species and ecosystem compartments to the overall riparian carbon reservoir. We used a combined field and object-based image analysis (OBIA) approach, based on unmanned aerial vehicle (UAV) multispectral imagery, to assess C stock of three dominant riparian species. A linear discriminator was designed, based on a set of spectral variables previously selected in an optimal way, permitting the classification of the species corresponding to every object in the study area. This made it possible to estimate the area occupied by each species and its contribution to the tree aboveground biomass (AGB). Three uncertainty levels were considered, related to the trade-off between the number of unclassified and misclassified objects, leading to an error control associated with the estimated tree AGB. We found that riparian woodlands dominated by Acacia dealbata Link showed the highest average carbon stock per unit area (251 ± 90 tC ha−1) followed by Alnus glutinosa (L.) Gaertner (162 ± 12 tC ha−1) and by Salix salviifolia Brot. (73 ± 17 tC ha−1), which are mainly related to the stem density, vegetation development and successional stage of the different stands. The woody tree compartment showed the highest inputs (79%), followed by the understory vegetation (12%) and lastly by the soil mineral layer (9%). Spectral vegetation indices developed to suppress saturation effects were consistently selected as important variables for species classification. The total tree AGB in the study area varies from 734 to 1053 tC according to the distinct levels of uncertainty. This study provided the foundations for the assessment of the riparian carbon sequestration and the economic value of the carbon stocks provided by similar Mediterranean riparian forests, a highly relevant ecosystem service for the regulation of climate change effects.