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- Drivers of Insect Community Change along the Margins of Mountain Streams in Serra da Estrela Natural Park (Portugal)Publication . Ceia-Hasse, Ana; Boieiro, Mário; Soares, Albano; Antunes, Sandra; Figueiredo, Hugo; Rego, Carla; Borges, Paulo A.V.; Conde, José; Serrano, ArturMountain ecosystems are important biodiversity hotspots and valuable natural laboratories to study community assembly processes. Here, we analyze the diversity patterns of butterflies and odonates in a mountainous area of high conservation value—Serra da Estrela Natural Park (Portugal)—and we assess the drivers of community change for each of the two insect groups. The butterflies and odonates were sampled along 150 m transects near the margins of three mountain streams, at three elevation levels (500, 1000, and 1500 m). We found no significant differences in odonate species richness between elevations, but marginal differences (p = 0.058) were found for butterflies due to the lower number of species at high altitudes. Both insect groups showed significant differences in beta diversity (βtotal) between elevations, with species richness differences being the most important component for odonates (βrich = 55.2%), while species replacement drove the changes between butterfly assemblages (βrepl = 60.3%). Climatic factors, particularly those depicting harsher conditions of temperature and precipitation, were the best predictors of total beta diversity (βtotal) and its components (βrich, βrepl) for the two study groups. The study of insect biodiversity patterns in mountain ecosystems and of the role played by different predictors contribute to further our understanding on the community assembly processes and may help to better predict environmental change impacts on mountain biodiversity.
- Using a space-for-time approach to select the best biodiversity-based indicators to assess the effects of aridity on Mediterranean drylandsPublication . Frasconi Wendt, Clara; Nunes, Alice; Verble, Robin; Santini, Giacomo; Boieiro, Mário; Branquinho, CristinaMediterranean drylands are particularly vulnerable to predicted increases in aridity which are expected to have negative consequences for biodiversity. To understand the effects of climate change on ecosystems, a framework for the selection of indicators based on the essential biodiversity variables (EBV) was proposed. In this framework, a functional approach has been suggested because functional traits have shown to be sensitive to small-scale environmental changes. Additionally, functional traits are also associated with ecosystem-limiting processes. In this context, we used ants as ecological indicators, as they are functionally important and respond in a measurable way to environmental changes. We identify which biodiversity-based indicators (e.g., taxonomic, single-trait and multi-trait indices) help track changes in Mediterranean drylands; for this, we used a space-for-time substitution climatic gradient in the western Mediterranean. Ants were sampled along an aridity gradient and identified to species level. Four continuous and seven categorical traits were measured or retrieved from literature. Continuous traits included Weber’s length, which is indicative for body length, head length, eye length and femur length; categorical traits were diet, behavioral dominance, daily activity, nest preference, mound presence, worker polymorphism and foraging strategy. We calculated taxonomic, functional structure and single- and multi-trait functional diversity indices and correlated them with aridity. We found that ant taxonomic and multi-trait functional diversity were maintained along the aridity gradient. Despite maintenance of species and functional diversity along the gradient, ant functional structure responded to aridity with increases in mean trait values of Weber’s length, eye length and femur length in the drier part of the gradient. Under wetter conditions, we found the highest proportion of ants with a seed-based diet, reflecting a potential increase in resource quantity. We observed a change in foraging strategy from group to individual as aridity increased. In conclusion, with a space-for-time substitution climatic gradient, this study shows the potential role of aridity as an environmental driver of ant trait values. These results highlight the value of ants and functional traits as indicators to track the effects of climate change on ecosystems. Finally, this study represents a starting point to monitor important species traits in the context of EBV and to use them as indicators to track the effects of aridity on Mediterranean dryland ecosystems.
- Foraging Behavior and Pollen Transport by Flower Visitors of the Madeira Island Endemic Echium candicansPublication . Esposito, Fabiana; Costa, Ricardo; Boieiro, MárioThe study of flower visitor behavior and pollen transport dynamics within and between plants can be of great importance, especially for threatened or rare plant species. In this work, we aim to assess the flower visitor assemblage of the Madeiran endemic Echium candicans and evaluate the performance of the most common visitors through the analysis of their foraging behavior and pollen loads. The flower visitor assemblage of E. candicans is diverse, including several insect groups and the endemic lizard Teira dugesii, but bees are the most common visitors. In general, large bees (Amegilla quadrifasciata, Apis mellifera, and Bombus spp.) had the highest average visitation rates (>18 flowers/min) and their pollen loads had higher percentages of homospecific pollen (>66%) when compared with butterflies and hoverflies. The honeybee (Apis mellifera) and two bumblebees (Bombus terrestris and B. ruderatus) were the most efficient flower visitors of E. candicans, but their foraging behavior seems to favor geitonogamy. Other visitors, such as butterflies and the small bee Lasioglossum wollastoni, may have a complementary role to the honeybee and bumblebee species, as their high mobility is associated with fewer flower visits on each plant and may promote xenogamy. Two non-native bees (A. mellifera and B. ruderatus) are important flower visitors of E. candicans and may contribute mostly
- Inventory of tiger- and ground-beetles (Coleoptera, Caraboidea, Cicindelidae and Carabidae) in two sampling seasons of the Gorongosa National Park, MozambiquePublication . Serrano, Artur; Baptista, Martim; Carvalho, Rui; Boieiro, Mário; Mendes, Sara; Bartz, Marie; Timóteo, Sérgio; Azevedo-Pereira, Henrique; Aguiar, Carlos; Alves da Silva, António; Alves, Joana; Briones, Maria; Borges, P.A.V.; Sousa, José; Martins da Silva, PedroBackground The Gorongosa National Park (Mozambique) is one of the most emblematic protected areas in Africa, well known for its vertebrate biodiversity and restoration ecology efforts following the Mozambican civil war in 1992. The invertebrate biodiversity of Gorongosa National Park is still poorly studied, although the scarce information available indicates the existence of a rich number of species, namely in the case of tiger- and ground-beetles (Coleoptera, Caraboidea). Moreover, the study of arthropod assemblages is key for designing conservation practices since they are potentially accurate biodiversity and ecological indicators. Hence, the diversity assessment of Caraboidea beetles using standardised methodologies is likely to provide a new insight for future conservation planning and help to quantify the effects of climate change in areas identified as vulnerable to anthropogenic pressures, such as the Gorongosa National Park. New information We report the occurrence of five tiger beetles (Cicindelidae) and 93 ground-beetles (Carabidae) species/morphospecies in Gorongosa National Park from a field survey funded by the ECOASSESS project. Sampling was performed in the four main habitat types present in the Park (miombo tropical forest, mixed dry forest, transitional forest and grasslands) between 25 October and 25 November 2019. In this sampling window, the turnover of Caraboidea species from the dry season to the wet season was recorded for the first time. Twenty-eight species of ground-beetles are new records to Mozambique, including three new subgenera and three new genera. Additional information on species phenology and habitat preferences is also provided.
- Seed removal decrease by invasive Argentine ants in a high Nature Value farmlandPublication . Frasconi Wendt, Clara; Nunes, Alice; Lobo Dias, S.; Verble, Robin; Branquinho, Cristina; Boieiro, MárioSeed dispersal by ants is an important ecological process that maintains the structure and diversity of natural communities, however, it is vulnerable to biological invasions. Argentine ants are one of the worst invasive ant species and cause severe changes in ecosystem processes and native ant biodiversity declines in invaded sites. Here, we studied seed removal by ants combining observations and a cafeteria experiment with seeds of four myrmecochorous plant species (Centaurea sphaerocephala, Rosmarinus officinalis, Silybum marianum, and Ulex australis) in two sites (invaded and uninvaded) located in the Mediterranean Montado ecosystem and classified as High Nature Value farmland (HNV). Significant differences in daily seed removal rates were found between the two study sites. In uninvaded sites, several native ant species were attracted to the seeds, resulting in all seeds being removed rapidly. The majority of seed removal events were carried out by two key seed disperses Pheidole pallidula (71%) and Aphaenogaster iberica (26%) with a clear preference for diaspored with larger and heavier elaiosome (i.e., C. sphaerocephala, S. marianum). By contrast, while the Argentine ant showed some interest (68% of seeds were interacted with), no seed removal events were observed. The extirpation of the local ant fauna by the Argentine ant and its inability to ensure seed dispersal services may lead to the interference and eventually to the collapse of seed dispersal of the four studied myrmecochorous plants in the invaded site in the future. We argue that these discrete but severe consequences of an invasive species on a key ecological process may strongly affect the functioning of the Montado ecosystem.
- A comparative analysis of terrestrial arthropod assemblages from a relict forest unveils historical extinctions and colonization differences between two oceanic islandsPublication . Boieiro, Mário; Matthews, Thomas J.; Rego, Carla; Crespo, Luis; Aguiar, Carlos A. S.; Cardoso, Pedro; Rigal, François; Silva, Isamberto; Pereira, Fernando; Borges, P.A.V.; Serrano, ArturDuring the last few centuries oceanic island biodiversity has been drastically modified by human-mediated activities. These changes have led to the increased homogenization of island biota and to a high number of extinctions lending support to the recognition of oceanic islands as major threatspots worldwide. Here, we investigate the impact of habitat changes on the spider and ground beetle assemblages of the native forests of Madeira (Madeira archipelago) and Terceira (Azores archipelago) and evaluate its effects on the relative contribution of rare endemics and introduced species to island biodiversity patterns. We found that the native laurel forest of Madeira supported higher species richness of spiders and ground beetles compared with Terceira, including a much larger proportion of indigenous species, particularly endemics. In Terceira, introduced species are well-represented in both terrestrial arthropod taxa and seem to thrive in native forests as shown by the analysis of species abundance distributions (SAD) and occupancy frequency distributions (OFD). Low abundance range-restricted species in Terceira are mostly introduced species dispersing from neighbouring man-made habitats while in Madeira a large number of true rare endemic species can still be found in the native laurel forest. Further, our comparative analysis shows striking differences in species richness and composition that are due to the geographical and geological particularities of the two islands, but also seem to reflect the differences in the severity of human-mediated impacts between them. The high proportion of introduced species, the virtual absence of rare native species and the finding that the SADs and OFDs of introduced species match the pattern of native species in Terceira suggest the role of man as an important driver of species diversity in oceanic islands and add evidence for an extensive and severe human-induced species loss in the native forests of Terceira.
- Local environmental variables are key drivers of ant taxonomic and functional beta-diversity in a Mediterranean drylandPublication . Frasconi Wendt, Clara; Ceia-Hasse, Ana; Nunes, Alice; Verble, Robin; Santini, Giacomo; Boieiro, Mário; Branquinho, CristinaThe decomposition of beta-diversity (β-diversity) into its replacement (βrepl) and richness (βrich) components in combination with a taxonomic and functional approach, may help to identify processes driving community composition along environmental gradients. We aimed to understand which abiotic and spatial variables influence ant β-diversity and identify which processes may drive ant β-diversity patterns in Mediterranean drylands by measuring the percentage of variation in ant taxonomic and functional β-diversity explained by local environmental, regional climatic and spatial variables. We found that taxonomic and functional replacement (βrepl) primarily drove patterns in overall β-diversity (βtot). Variation partitioning analysis showed that respectively 16.8%, 12.9% and 21.6% of taxonomic βtot, βrepl and βrich variation were mainly explained by local environmental variables. Local environmental variables were also the main determinants of functional β-diversity, explaining 20.4%, 17.9% and 23.2% of βtot, βrepl and βrich variation, respectively. Findings suggest that niche-based processes drive changes in ant β-diversity, as local environmental variables may act as environmental filters on species and trait composition. While we found that local environmental variables were important predictors of ant β-diversity, further analysis should address the contribution of other mechanisms, e.g. competitive exclusion and resource partitioning, on ant β-diversity.
- Arthropod traits as proxies for abundance trends in the Azorean IslandsPublication . Oyarzabal, Guilherme; Cardoso, Pedro; Rigal, François; Boieiro, Mário; Santos, Ana M. C.; Amorim, Isabel R.; Malumbres‐Olarte, Jagoba; Costa, Ricardo; Lhoumeau, Sébastien; Pozsgai, Gabor; Gabriel, Rosalina; Borges, P.A.V.Human activities drive ecological transformation, impacting island ecosystems from species diversity to ecological traits, mainly through habitat degradation and invasive species. Using two unique long-term datasets we aim to evaluate whether species traits (body size, trophic level, dispersal capacity and habitat occupancy) can predict temporal variations in the abundance of endemic, indigenous (endemic and native non-endemic) and exotic arthropods in the Azores Islands. We found that body size is crucial to predict arthropod abundance trends. Small-bodied herbivorous arthropods showed a decrease in abundance, while large-bodied indigenous arthropods increased in abundance, mainly in well-preserved areas. Also, large-bodied exotic arthropods increased in abundance across the entire archipelago. Moreover, endemic canopy dwellers increased in abundance, while endemic ground-dwellers decreased in abundance. Simultaneously, exotic arthropods showed the opposite result, increasing in abundance in the ground while decreasing in abundance in the canopy. Finally, habitat influenced both endemic and exotic spider abundance trends. Endemic spiders that occupy solely natural habitats experienced a decline in abundance, while exotic spiders in the same habitats increased in abundance. Our study underscores the significance of arthropod species traits in predicting abundance changes in island ecosystems over time, as well as the importance of monitoring species communities. Conservation efforts must extend beyond endangered species to protect non-threatened ones, given the increased extinction risk faced by even common species on islands. Monitoring and restoration programs are essential for preserving island ecosystems and safeguarding endemic arthropod populations.
- Ant functional structure and diversity changes along a post-grazing succession in Mediterranean oak woodlandsPublication . Frasconi Wendt, Clara; Nunes, Alice; Köbel, Melanie; Verble, Robin; Matos, Paula; Boieiro, Mário; Branquinho, CristinaGrazing exclusion may be used to promote the recovery of disturbed ecosystems. A promising way for the evaluation of its effectiveness is through the monitoring of key biological groups, particularly those more responsive to disturbance and playing key roles in ecosystem functioning. Ants have been used as ecological indicators as they are abundant, diverse and sensitive to environmental changes. Here, we aimed to evaluate changes in ant taxonomic and functional structure and diversity, using functional groups, along a post-grazing succession in a Mediterranean oak woodland and to understand which environmental variables drive them. The post-grazing succession comprised a chronosequence of grazing excluded sites for 8, 12 and 18 years and a grazed control site. We found that ant species richness, functional structure and diversity increased with years since grazing exclusion: Generalist/Opportunist and the Hot Climate specialists increased in the 18 years grazing excluded site, while the Cryptic Species group increased in the 12 years grazing excluded site. Yet, their responses were not linear over time. Time since grazing exclusion and vegetation structure explained differences in ant taxonomic and functional structure and diversity. The Invasive/Exotic group dominated in all sites, except in the longest excluded site, where it occurred in the lowest proportion. The invasive Argentine ant dominated the grazed site, where it may have led to ant taxonomic and functional homogenization. Our results suggest that the time and changes in habitat structure may favour the recovery of ant biodiversity, although the presence of the invasive Argentine ant species may have slowed it down.
- Consistency of impact assessment protocols for non-native speciesPublication . González-Moreno, Pablo; Lazzaro, Lorenzo; Vilà, Montserrat; Preda, Cristina; Adriaens, Tim; Bacher, Sven; Brundu, Giuseppe; Copp, Gordon H.; Essl, Franz; García-Berthou, Emili; Katsanevakis, Stelios; Moen, Toril Loennechen; Lucy, Frances E.; Nentwig, Wolfgang; Roy, Helen E.; Srėbalienė, Greta; Talgø , Venche; Vanderhoeven, Sonia; Andjelković, Ana; Arbačiauskas, Kęstutis; Auger-Rozenberg, Marie-Anne; Bae, Mi-Jung; Bariche, Michel; Boets, Pieter; Boieiro, Mário; Borges, Paulo; Canning-Clode, João; Cardigos, Federico; Chartosia, Niki; Cottier-Cook, Elizabeth Joanne; Crocetta, Fabio; D'hondt, Bram; Foggi, Bruno; Follak, Swen; Gallardo, Belinda; Gammelmo, Øivind; Giakoumi, Sylvaine; Giuliani, Claudia; Guillaume, Fried; Jelaska, Lucija Šerić; Jeschke, Jonathan M.; Jover, Miquel; Juárez-Escario, Alejandro; Kalogirou, Stefanos; Kočić, Aleksandra; Kytinou, Eleni; Laverty, Ciaran; Lozano, Vanessa; Maceda-Veiga, Alberto; Marchante, Elizabete; Marchante, Hélia; Martinou, Angeliki F.; Meyer, Sandro; Minchin, Dan; Montero-Castaño, Ana; Morais, Maria Cristina; Morales-Rodriguez, Carmen; Muhthassim, Naida; Nagy, Zoltán Á.; Ogris, Nikica; Onen, Huseyin; Pergl, Jan; Puntila, Riikka; Rabitsch, Wolfgang; Ramburn, Triya Tessa; Rego, Carla; Reichenbach, Fabian; Romeralo, Carmen; Saul, Wolf-Christian; Schrader, Gritta; Sheehan, Rory; Simonović, Predrag; Skolka, Marius; Soares, António Onofre; Sundheim, Leif; Tarkan, Ali Serhan; Tomov, Rumen; Tricarico, Elena; Tsiamis, Konstantinos; Uludağ, Ahmet; van Valkenburg, Johan; Verreycken, Hugo; Vettraino, Anna Maria; Vilar, Lluís; Wiig, Øystein; Witzell, Johanna; Zanetta, Andrea; Kenis, MarcStandardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.