Diagnosis of the ecological condition of the drove road network in the Autonomous Community of Madrid (central Spain)

Context: Drove roads are landscape corridors traditionally used for livestock movement in many regions of the world, including Spain, where they cover about 0.8% of the land. They have ecological importance due to their role in connectivity, seed dispersal, soil preservation, habitat and biodiversity conservation, and the provision of ecosystem services. Drove roads are experiencing deterioration due to the abandonment of extensive grazing and transhumance. Objectives: We aim to characterize the conservation status and main predictors of deterioration of the drove roads in the Community of Madrid, a region in Spain with a high presence of these corridors. Methods: We considered all the network of the region, with the main analyses based on a sample of 160 segments of 200 m-long, which were evaluated using GIS and fieldwork. Results: Nearly one third of the network surface is occupied by crops, communication infrastructure, and urban or industrial surfaces. Natural habitats make up 60% of the network and are affected by soil degradation and grazing abandonment. Landscape matrix was the main predictor of drove road status, with urban and cropland matrices leading to a reduction in spatial integrity and availability for natural habitats. Grazing was most preserved in grassland matrices. Eco-district, drove road width, and distance to city center also had influence on conservation status. Conclusions: Despite their concerning state, the network is restorable in many areas of the region. Restoration should focus on intensified and simplified landscapes, where the network plays a more decisive role, and should consider the reintroduction of livestockOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the European Union Life Program (project LIFE CAÑADAS, LIFE 18 NAT/ES/000930

Edaphic arthropods as indicators of the ecological condition of temperate grassland ecosystems: A systematic review

Temperate grasslands are part of one of the biggest biomes on earth, sustaining high levels of biodiversity and providing multiple ecosystem services. However, the area covered by this open ecosystem is decreasing worldwide, due to several threats like land use change or climate change. Ground-dwelling arthropods are an important group of the community of grassland soil invertebrates, and they play a key role within this ecosystem, while at the same time being sensitive to the changes caused by management practices like grazing, mowing, prescribed fire, etc. Using the Web of Science database, we conducted a systematic review to identify which groups of arthropods are being used as indicators to evaluate the ecological condition of grasslands in temperate regions, and which indices are being measured. As grasslands have been traditionally managed by humans for centuries, their ecological condition is intrinsically linked to the development of different management practices like grazing, mowing or restoration strategies, which usually affect soil and vegetation structure. We found that macro-arthropods were used in a greater number of studies than micro-arthropods (91% vs 15%), and within that size group, beetles were the preferred indicator in most of the temperate grassland types (49% of the studies), followed by spiders and ants. Few studies used grasshoppers to monitor grasslands changes. The indices more frequently assessed were species richness and abundance, and we identified that the response to the different management practices was quite heterogeneous. Restoration and grazing effects were the two factors more frequently evaluated for macro-arthropods, while micro-arthropods (Acari and Collembola) were dominant to assess land use type. Overall, our findings highlight the need to increase the number of studies in some temperate regions, to explore the potential of overlooked groups of arthropods, and to include indices that measure functional diversity or community compositionThis work was financially supported by the European Union Life Program (project LIFE CANADAS, LIFE 18 NAT/ES/000930

Ant Communities Resist Even in Small and Isolated Gypsum Habitat Remnants in a Mediterranean Agroecosystem

Natural and seminatural habitat remnants play a crucial ecological role in intensified agroecosystems. Assumptions on the conservation value of small and poorly connected fragments in a hostile matrix come from generalization obtained from a limited number of taxa, mostly plants, and vertebrates. To date, few studies have analyzed the effect of fragmentation on ant communities in Mediterranean agroecosystems, despite the importance of this group of animals on several key ecosystem functions and services. Here, we analyze the effects of fragment area and connectivity on ant communities in gypsum outcrops in a large cereal agroecosystem of Central Spain. Ant communities were described by their species composition, abundance (total number of occurrences), and number of species, standardized both by area (species density), and abundance (species richness). Observed number of species was relatively high in comparison with other studies in the Mediterranean, and we found no effects of fragment characteristics on species density, species richness and species composition, which implies that even small and isolated patches do have a value for ant conservation. Moreover, total number of occurrences were higher for smaller and more isolated fragments. This finding contrasts with the results reported for other taxa in similar gypsum habitats and suggests that certain ant traits and strategies make them particularly resistant to fragmentation and capable to take advantage of small habitat patches. Given the important ecological role played by ants, we recommend the preservation of these small habitat fragments in the management plans of agroecosystems in these drylands, especially in those cases in which intensification of agricultural practices greatly diminish natural habitat availabilit

Diversity and mean specific leaf area of Mediterranean woody vegetation changes in response to summer drought across a double stress gradient: The role of phenotypic plasticity

Aim: Many aspects of vegetation response to increased drought remain uncertain but it is expected that phenotypic plasticity may be key to early adaptation of plants to environmental stress. In this work we observe the response of specific leaf area (SLA) of woody shrub vegetation to the summer drought typical of the Mediterranean climate. In addition, to observe the possible interaction between the impact of drought and the environmental characteristics of the ecosystems, communities from different edaphic and structural contexts distributed along the double stress gradient of the Mediterranean mountains (high temperature and low precipitation at low elevation; low temperature and high irradiation at high elevation) have been analysed. Location: Central Mountain range of the Iberian Peninsula. Methods: Along the entire altitudinal gradient, 33 shrub communities belonging to different habitat typologies (shrublands, rocky areas, hedgerows, understorey) were sampled before and after the passage of summer, both in 2017 and 2019. A total of 1724 individuals and 15,516 leaves were collected and measured to estimate the mean values and diversity of SLA of each community. Results: The community-weighted mean and functional divergence have inverse quadratic relationships with the environmental gradient. Shrub communities at both ends of the gradient have low mean SLA values and high functional divergence of this trait. Summer drought implies a generalised decrease in the mean SLA of the communities throughout the gradient, as well as an alteration in functional richness and uniformity. However, the effect of summer drought on the plant community is mediated by the microenvironmental characteristics of its habitat. Conclusions: Drought acclimatisation of shrub communities through phenotypic plasticity leads to rapid changes in their functional leaf structure. In the long term, our results point to an increase in plant conservative strategies, reduced ecosystem productivity, slower nutrient recycling and the reduction of communities of specific habitats as drought increasesAdministrative and financial support was received from the Autonomous Community of Madrid (Project REMEDINAL TECM S2018/EMT-4338) and Sierra de Guadarrama National Park, which provided the permits for the sampling within the park (ref 10/097831.9/18). Alejandro Carrascosa was supported by a grant for the Promotion of Research in UAM Master studies (UAM 2018– 2019), and Mariola Silvestre by an FPI grant from MINEC

A new host for a new Rossomyrmex minuchae population

Social parasites usually rely on chemical cues (cuticular hydrocarbons) to successfully invade and coexist with their hosts. Most ants that are obligate social parasites (slave-makers) can parasitize several related host species with different levels of chemical similarity although there are few exceptions where there is only a single host species. An example of the latter is Rossomyrmex minuchae, which was known to be only associated with Proformica longiseta. However, a recent discovery of a new R. minuchae population revealed that it can parasitize P. nasuta, a species with a separate distribution to P. longiseta. Chemical analyses of cuticular hydrocarbons show local adaptation of the parasite to its host in this new population, being more similar to P. nasuta than to other R. minuchae populations. In addition, genetic analyses evidence differences from the other known populations, from which it split 1.21 Mya during glacial and interglacial periods of the Pleistocene and remained separated to the present day. This historical genetic isolation and the chemical differences found between parasite populations may evidence a speciation process and support the local host–parasite coevolutionM Silvestre and FM Azcárate received administrative and fnancial support from the Spanish Ministry of Economy and Competitiveness (Project CGL2014-53789-R). Sierra de Guadarrama National Park provided the permits for the sampling (ref 10/101642.9/16). This work was also partially funded by the University of Jaén through the “Plan Operativo de Apoyo a la Investigación 2021-2022