Carabid community stability is enhanced by carabid diversity but reduced by aridity in Chinese steppes Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Noelline Tsafack, Letizia Di Biase, Yingzhong Xie, Xinpu Wang, Simone Fattorini Abstract Carabids (Coleoptera, Carabidae) are an important arthropod component of grassland ecosystems, where they are involved in many important ecosystem services. Grasslands are the most widespread ecosystems in China, where they are under increasing degradation that turn productive grasslands into desert. We studied the relationships between carabid community stability and various community parameters (richness, diversity, dominance, evenness, and proportion of the most dominant species) in three types of steppes characterized by a different degree of aridity (desert, typical and meadow) in northern China. Carabid community stability was lowest in the most arid environment (i.e. the desert steppe). In the less arid steppe (i.e. the meadow steppe) stability was correlated positively with richness, diversity, and equitability, and negatively with dominance and proportion of the most abundant species. This supports the diversity hypothesis (i.e. that high levels diversity lead to higher levels of stability, possibly by increasing niche complementation) and falsifies the mass ratio hypothesis (i.e. that ecosystem processes, and hence their stability, are strongly influenced by the most dominant species). Current transformation of productive grasslands into arid lands will reduce carabid community stability and this might compromise ecosystem functioning even at moderate levels of degradation, as observed in the typical steppe.

Low fruit-crop years of Carapa oreophila drive increased seed removal and predation by scatterhoarding rodents in a West African forest Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Biplang G. Yadok, Pierre-Michel Forget, Daniel Gerhard, Hazel Chapman

Soil fauna community and ecosystem's resilience: A food web approach Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Gisela Maggiotto, Leticia Sabatté, Tomás I. Marina, Luciana Fueyo-Sánchez, Angélica M. Ramírez Londoño, Mónica Díaz Porres, Macarena Rionda, Marianela Domínguez, Rosa Perelli, Fernando R. Momo Abstract There is an increasing concern for the conservation of soil biodiversity and its ecosystem functions. In this context, it is crucial to comprehend the typical response times of the community (meso and macrofauna) to disturbances associated with different land uses. If we consider a disturbance as some degree of disorganization produced by an input of energy into the system, we realise that the issue is how the surplus of energy is dissipated, and with at what efficiency. Emerging properties of a community (diversity, resilience, stability) are affected by a cascade of processes that act at different spatial and temporal scales. To diagnose disturbance effects, it is necessary to use new tools of observation. One of these tools is the analysis of food webs that clearly shows the relationships among species and energy fluxes. We present here an example of the use of the food web approach to study the effects of foresting a naturalized pasture of the humid Argentinean Pampa with exotic species of trees (Eucalyptus camadulensis and Populus nigra). We show that the basic architecture of food webs remains similar under different treatments (related to the input of new detritus source) in a short time (60 days). However, the proposed approach in this study enables to design a simple decision scheme to formulate hypotheses about possible effects of stronger disturbances.

Distinct seeds in contrasting habitats: Morphological and reproductive responses in Butia eriospatha to new environmental conditions Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Rafael Candido-Ribeiro, Miguel Busarello Lauterjung, Tiago Montagna, Alison Paulo Bernardi, Newton Clóvis Freitas da Costa, Marcia Patricia Hoeltgebaum, Maurício Sedrez dos Reis Abstract Distinct environments drive particular responses in the reproduction pattern of plants and may have ecological and evolutionary consequences for local populations. Currently, populations of the palm Butia eriospatha are found in forests and open grasslands in southern Brazil, providing opportunities to investigate how this species responds to recent habitat transformations. We assessed phenology and fruit morphology in two geographically close populations of B. eriospatha under contrasting environmental conditions – forest and open grassland – to address the following questions: 1) Are there phenotypic differences between populations of B. eriospatha occurring in contrasting habitats? 2) What ecological and evolutionary consequences could those differences impose on local populations? Greater variation was observed within the forest population. The grassland population showed lighter endocarps on average, reflecting a greater proportion of pulp per fruit, but smaller seeds, which may suggest plasticity, local adaptation, or both after the habitat transformation. Reproductive status is dependent on individuals' sizes in the forest environment but not for the open grassland population. Additionally, the average production of infructescences per individual is lower in the forest environment. Our findings indicate that the transformation of B. eriospatha's habitat has promoted important phenotypic changes. We emphasize the importance of forest environments in promoting dispersal selectivity, which may increase population fitness through time.

Can environmental complexity predict functional trait composition of ground-dwelling ant assemblages? A test across the Amazon Basin Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Diego Rodrigues Guilherme, Jorge Luiz Pereira Souza, Elizabeth Franklin, Pedro Aurélio Costa Lima Pequeno, Andreia Conceição das Chagas, Fabricio Beggiato Baccaro Abstract Environmental gradients may influence species distributions by filtering their functional traits, resulting in a correspondence between community functional composition and local environmental conditions. We used a vegetation gradient as an indicator for environmental complexity to test whether it predicted the morphological composition of ground-dwelling ant assemblages across geographic extents. The sampling design covered 126 plots distributed across eight sampling sites along a broad environmental gradient in the Amazon Basin. Plots covered different phytophysiognomies that have a strong relation with forest biomass and, consequently, litter production. We selected six morphological traits related to ant foraging strategies and behavior. Generalized linear mixed models were used to predict how environmental complexity affects trait composition of ground-dwelling ant assemblages. Structurally less complex environments (eg. Amazonian savannah) harboured more species of smaller ants, with relatively smaller mandibles and relatively larger eyes. In more complex environments (eg. dense ombrophylous forest), there were more ant species of larger size, with relatively larger mandibles and relatively smaller eyes. No relationship was detected between relative femur length and the environmental gradient investigated. The functional approach focused on individual traits may illuminate which ant foraging strategies are best adapted to a particular habitat. Our data reveal that the morphological composition of ground-dewelling ant assemblages responds clearly to environmental complexity suggesting that certain ant characteristics offer ecological advantages to particular species in particular habitats. Graphical abstract

Exploring the relationships between aquatic macrophyte functional traits and anthropogenic pressures in freshwater lakes Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Dimitrios Zervas, Vasiliki Tsiaoussi, Athanasios S. Kallimanis, Panayotis Dimopoulos, Ioannis Tsiripidis Abstract Modern water resource management requires biomonitoring of the structure and functioning of freshwater ecosystems, which may be better illuminated by functional trait distribution patterns and responses across human-induced pressure gradients. In this study, we applied the RLQ, the fourth-corner and their novel combination methods, in order to assess the relationship between the distribution of 30 aquatic macrophyte functional traits and 14 indicators of anthropogenic pressures across 16 freshwater lakes. Our findings showed that there is a statistically significant relationship between the distribution of specific functional traits and anthropogenic pressures. Eutrophication was the dominant pressure and the shift from a submerged-macrophyte dominated vegetation community to an emergent one was the most important functional response. Aerial reproduction and dispersal traits were found to replace water-related ones under higher nutrient concentrations. Trophic and light preferences of macrophytic species increased, while their leaf morphology was found to change from tubular/capillary leaf types with low leaf area values to entire leaf types with greater leaf area. These results provide hints on the changes in ecosystem functioning occurring as a response to human-induced drivers. Therefore, this assessment approach could provide important support to the tasks of biomonitoring, conservation and management planning in freshwater ecosystems. Graphical abstract

Feral swine harming insular sea turtle reproduction: The origin, impacts, behavior and elimination of an invasive species Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Richard M. Engeman, Robert W. Byrd, Jamie Dozier, Mark A. McAlister, James O. Edens, Elizabeth M. Kierepka, Timothy J. Smyser, Noel Myers Abstract Feral swine are among the world's most destructive invasive species wherever they are found, with translocations figuring prominently in their range expansions. In contrast, sea turtles are beloved species that are listed as threatened or endangered throughout the world and are the focus of intense conservation efforts. Nest predation by feral swine severely harms sea turtle reproduction in many locations around the world. Here we quantify and economically assess feral swine nest predation at North Island, South Carolina, an important loggerhead sea turtle nesting beach. Feral swine depredation of North Island sea turtle nests was first detected in 2005, with annual nest monitoring initiated in 2010 documenting nearly total losses to feral swine in 2010 and 2011. The cumulative valuation of annual losses for North Island from 2010 to 2016 ranged as high as $1,166,500. To improve nesting success, an integrated approach for eliminating feral swine was implemented in 2010 and greatly intensified in 2013 by adding federal experts. Removal efforts were challenging due to the island's remoteness and impenetrable habitats, weather, hazards in accessing the island, and wariness of the animals, especially as their population diminished. Removal of the final 11 swine required efforts from 2014 to 2016. Nest predation was highly variable and provided another example of the significance of conditioning by feral swine to sea turtle nests on the consequent severity of nest predation. Even the final individual inflicted heavy losses before his removal. Genetic analyses of feral swine removed from North Island and the adjacent mainland revealed that the island's population did not originate from the nearby mainland, meaning they were (illegally) introduced to the island.

Richness and distribution of Ephemeroptera, Plecoptera and Trichoptera in Atlantic forest streams Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Pedro Henrique Monteiro do Amaral, Emanuel de Almeida Gonçalves, Lidimara Souza da Silveira, Roberto da Gama Alves Abstract Knowledge about the distribution of aquatic insects in different types of mesohabitats is very important for conservation of benthic macrofauna. This study evaluated the composition and spatial distribution of the fauna of Ephemeroptera, Plecoptera and Trichoptera (EPT) in eight streams in forested areas in the southeastern region of Minas Gerais state, Brazil. The collections were carried out in the dry season, obtaining 10 litter samples from riffles and 10 from pools in each stream, using a Surber sampler. We identified 5,631 organisms of 49 EPT genera. The abundance and fauna composition values differed between the streams and mesohabitats, while the richness only differed between the streams. Eleven taxa were recorded with greatest abundance and frequency in riffles and six in pools. The results suggest that the abiotic characteristics at the stream scale (e.g., water temperature) and mesohabitat scale (water speed) are the main determinants of the variation in the structure and composition of the EPT assemblages, reinforcing the importance of separately evaluating samples from different types of mesohabitats.

Assessing the resistance of a breeding amphibian community to a large wildfire Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Alberto Muñoz, Ángel M. Felicísimo, Xavier Santos Abstract Socioeconomic and global climate changes are modifying fire regimes towards larger and more intense fires. Studying the response of organisms to the occurrence of large fires is crucial to anticipate shifts in patterns of biodiversity in fire-prone regions. Amphibia is the most threatened terrestrial vertebrate taxon, although it is also the least studied in relation to its response to fire. We evaluated the resistance to fire (similarity in species composition before and after fire) and reproductive success during the first breeding season after a fire of an amphibian community at the Mediterranean basin. We sampled 33 aquatic habitats, including ponds and streams located inside and outside the perimeter of the fire, and reported the presence of adult amphibians and their reproductive success. The community composition in burnt and unburnt areas was compared by similarity analysis. Generalized Linear Models were used to test the effects of fire (burnt or unburnt area), habitat type (stream or pond), distance to the perimeter of the wildfire, and altitude on total and breeding species richness. We did not find significant differences in amphibian community composition between burnt and unburnt areas, or in total species richness per water point. Of the 12 species found in the study area, only frogs of the genus Hyla declined in the burnt area due to the destruction of their preferred microhabitat, i.e. vegetation surrounding ponds. In contrast, breeding occurrence and breeding species richness declined in burnt streams and ponds. These results suggest a high amphibian resistance to fire at the community level, although the reduction of breeding activity can threaten the persistence of a rich community in future scenarios of increased recurrence of megafires.

The effects of grassland ecosystem afforestation on avian phylogenetic diversity, taxonomic diversity and evolutionary distinctiveness Publication date: August 2019 Source: Acta Oecologica, Volume 99 Author(s): Lucilene I. Jacoboski, André L. Luza, Raquel K. Paulsen, Angelo M. Pezda, Sandra M. Hartz Abstract Forest plantations are among the main threats to the grassland ecosystems of southeastern South America. One key question is whether such plantations affect the evolutionary diversity of bird communities, since previous studies have shown a reduction in taxonomic and functional diversity. High levels of phylogenetic diversity can ensure the conservation of communities, and high evolutionary potential to adapt to environmental changes. Taking this into account we investigated whether the conversion of native grasslands into forest plantations impacted the evolutionary and taxonomic diversity of bird communities, through an analysis of the different dimensions of diversity. Our investigations took place in southern Brazil where native grasslands predominate, however many have been afforested in recent years. We collected data from bird communities in native grassland and forest habitats, as well as from eucalyptus plantations. Our results did not detect a reduction in phylogenetic diversity in the planted areas but did demonstrate the taxonomic impoverishment of bird communities. Furthermore, we registered a reduction in the evolutionary distinctiveness of bird communities in forest plantations and a variation of phylogenetic composition among habitats. This indicates the evolutionary adaptations of species to their habitat, whether it is forest or grassland. Riparian forest lineages appeared more capable of colonizing forest plantations, while grassland lineages appeared unfit to do so. Afforestation of grassland ecosystems may represent a future threat to the maintenance of evolutionarily distinct bird species, as well as to strict grassland species which have been shown to be evolutionarily unable to colonize forest plantations. We recommend the maintenance of forest plantations only in areas that have already been converted or degraded. Additionally, we emphasize the importance of practicing non-intensive economic activities in these areas, for example, cattle production in low-intensity. Such activities in low-intensity have been shown to be beneficial for the maintenance of the evolutionary and taxonomic diversity of bird communities.