Land-use intensification and climate change have strong filtering effects on arthropod communities. Intensification increases landscape homogeneity and field-scale disturbance while extreme weather events are increasing with climate change. To disentangle their impacts, we analyzed predatory arthropod abundance and diversity across microhabitats (canopy, ground) and diet breadth (specialist, generalist, omnivore) in 58 sorghum fields in Uruguay over two years. Using a trait-based framework and Hierarchical Modelling of Species Communities, we found that double cropping negatively affected predator communities, reducing canopy predator abundance and ground predator species richness, especially ground omnivores. Larger fields decreased the proportion of canopy specialists in the community, and landscape homogeneity increased the proportion of ground omnivores. Extreme weather mainly affected ground predators, with species richness and abundance decreasing with high rainfall variability. The proportion of ground specialists decreased with both variable rainfall and more hot days. Omnivorous and generalist ground predators were more resilient to climatic stress and canopy predator abundance increased under heat extremes. Our findings suggest that land-use intensification exerts stronger negative effects on predator communities than extreme weather, though the latter can further reduce functional diversity. To enhance predator community resilience and support biological control, management strategies should prioritize reducing disturbances, such as double-cropping, and creating refuges within fields to protect against climatic extremes.

Biocontrol services are widely recognized to provide key incentives for bat conservation. However, we have virtually no information on whether and how disruptions in bat-mediated biocontrol services are driven by mismatches between the temporal activity patterns of insectivorous bats and insect pests. We investigated the temporal relationship between the nightly activity patterns of the common pipistrelle bat (Pipistrellus kuhlii) and the olive fruit moth (Prays oleae). Temporal mismatches between species pairs were estimated as the time difference (expressed as a percentage of the night) at which P. kuhlii and P. oleae reached 50% of their abundance. The study was carried out during spring, summer, and fall between 2017 and 2019 in 60 olive farms representing increasing levels of structural simplification (as a surrogate of agricultural intensification). Olive farms were classified as exhibiting high (i.e. HIGH olive farms; n = 27), intermediate (MID; n = 18), and low (LOW; n = 15) structural complexity. Temporal mismatches between the activity levels of P. kuhlii and P. oleae varied between seasons and types of olive farms, being comparatively lower in summer than in spring and fall. Furthermore, summer was the only season in which temporal mismatches between species pairs differed between types of olive farms, with higher temporal mismatches found in LOW than in HIGH and MID olive farms. Overall, our work demonstrates the existence of temporal mismatches between the nightly activity patterns of P. kuhlii and P. oleae. Furthermore, it demonstrates that the structural simplification of olive farms increases temporal mismatches between species pairs, particularly in summer when bat-mediated biocontrol services are most needed. Synthesis and applications. Future research should consider mismatches between the temporal activity patterns of insectivorous bats and insect pests. Otherwise, the actual impact of agricultural intensification on bat-mediated biocontrol services as well as the economic impact of their loss on the agriculture industry might be underestimated. To enhance biocontrol services, we propose increasing the availability of suitable roosting and foraging sites as well as conserving areas of remnant native woodland and scattered hollow-bearing trees.

Knowledge about cold tolerance of non-native biological control agents is critical to avoid permanently establishing them in new temperate areas outside of their native range. The cold tolerance of the predatory mites, Amblydromalus limonicus and Iphiseius degenerans, was investigated in the laboratory to assess their establishment potential in northern Europe, particularly Sweden. The lethal time of I. degenerans (the number of days until 100% mortality was reached) declined steeply from 5 degrees C to 0 degrees C and was almost zero at -5 degrees C. The lethal time of A. limonicus did not differ between 5 degrees C and 0 degrees C, but was reduced at -5 degrees C. For both species, LTime50 (the number of days until 50% of the mites died) was longer for fed than for unfed mites. The lethal temperature of A. limonicus (the temperature at which 100% mortality was reached) was -17.75 degrees C, whereas most I. degenerans died at -8.5 degrees C. LTemp50 (the temperature at which 50% of the mites died) was lower for A. limonicus (-9.8 degrees C) than for I. degenerans (-0.1 degrees C). Collectively, these findings suggest that I. degenerans is unlikely to establish in Sweden but that A. limonicus is more cold tolerant. This highlights the risk associated with releasing A. limonicus in Sweden due to concerns about potential establishment.

Intensified agriculture, a driver of biodiversity loss, can diminish ecosystem functions and their stability. Biodiversity can increase functional redundancy and is expected to stabilize ecosystem functions. Few studies, however, have explored how agricultural intensity affects functional redundancy and its link with ecosystem function stability. Here, within a continental-wide study, we assess how functional redundancy of seed predation is affected by agricultural intensity and landscape simplification. By combining carabid abundances with molecular gut content data, functional redundancy of seed predation was quantified for 65 weed genera across 60 fields in four European countries. Across weed genera, functional redundancy was reduced with high field management intensity and simplified crop rotations. Moreover, functional redundancy increased the spatial stability of weed seed predation at the field scale. We found that ecosystem functions are vulnerable to disturbances in intensively managed agroecosystems, providing empirical evidence of the importance of biodiversity for stable ecosystem functions across space. Within a continent-wide study, we assess the impact of agricultural intensity and landscape simplification on the functional redundancy of weed seed predation. We found that functional redundancy was reduced with high field management intensity and simplified crop rotations. Additionally, high functional redundancy increased the spatial stability of weed seed predation, underscoring the importance of biodiversity in maintaining stable ecosystem functions across space in intensively managed agroecosystems.image

Assessing the spatio-temporal impact of agricultural intensification on species and communities is key for biodiversity conservation. Here, we investigated the seasonal effects of olive grove intensification at both local (farming practices and grove structural complexity) and landscape scale (land-cover diversity) on birds and bats, at species and community-level. Both groups were surveyed during spring, summer, and autumn in 60 sites representing varying levels of olive grove intensification throughout the Alentejo region (southern Portugal). At the local scale, the number of chemical applications was used as a proxy for the intensification of farming practices and a Structural Index, which accounted for within-grove variability in tree density and features, was used as a measure of grove structural complexity. At landscape scale, we quantified the proportion of the major land-cover types potentially affecting birds and bats. We found that the abundance of ca. 77% of the species analyzed (ca. 84% and 55% of birds and bats respectively) was negatively related to olive grove intensification in at least one season. The Structural Index was the most influential factor at both species and community-levels, especially for birds, with a consistent and strong effect across seasons. Chemical applications had a stronger negative effect on birds, whereas the amount of olive grove cover had a stronger detrimental effect on bats. Birds and bats showed a variable response to predictor variables depending on the season, particularly for the bat community. Our study shows differences in bird and bat responses associated with the spatio-temporal variability of the agricultural intensification components. On the one hand, birds and bats showed a seasonal pattern of association with the different components of olive grove intensification, probably due to their ecological and biological requirements. On the other hand, the responses of both groups also appear to be scale-dependent: while birds seem to respond to in-farm or local intensification more strongly, bats seem to be more influenced by landscape-scale simplification. Overall, we highlight the importance of the structural complexity of olive groves for birds and bats, an aspect that should be considered in the design of agricultural policies aiming to promote biodiversity conservation.

Public health and environmental concerns are increasing the pressure to reduce chemical pesticide usage, thereby requiring management alternatives to control pest damage to crops. Retaining semi-natural habitats within agricultural landscapes is often assumed to be one such alternative, by contributing to boost natural enemy populations and reduce pest abundance and spread. However, these potential benefits might be diluted or counteracted by intensive field management, thus limiting their effectiveness. We test these hypotheses, focusing on olive farming in southern Portugal, where we quantified the abundance of three pests, the olive fruit fly (Bactrocera oleae), olive moth (Prays oleae) and olive psyllid (Euphyllura olivina), and their parasitism and infestation rates in 17 orchards representing an intensification gradient and varying landscape cover by oak woodlands. Fly infestation was lower in more intensive orchards, there were no woodland effects, and parasitism was never detected. Psyllid infestation was also lower in more intensive orchards, but declined with woodland cover in more intensive orchards, while slightly increasing in less intensive ones. Psyllid parasitism rate could not be confidently estimated. Moth infestation declined with woodland cover in the most intensive orchards, while varying little in less intensive orchards. Moth parasitism rate declined with intensification and increased with woodland cover, particularly in less intensive orchards. Infestation by the moth was positively related to its abundance, albeit less so when parasitism rates were higher. Overall, our findings show mixed effects of oak woodlands, although retaining such habitats might still enhance biocontrol potential and reduce pressure by some pests, even under management intensification.

The first observations of the Monarch butterfly (Danaus plexippus) in Iberia date from 1886, although breeding records emerged almost a century later: 1960 in Spain, 1980s–1990s in Madeira and Azores, and 2003 in mainland Portugal. We reviewed the history of the colonisation of mainland and insular Portugal by the Monarch butterfly and its hostplants (Gomphocarpus fruticosus, G. physocarpus and Asclepias curassavica). We also compiled available historical and recent occurrence records as a basis for countrywide surveys of the butterfly and hostplants, to update their current distributions in Portugal. Locations for only a few of the older records represented newly rediscovered populations in the field, although recent occurrences were often confirmed. Hostplants were scarce and monarchs absent in northern and central mainland Portugal, but both were quite common in the southwest. In Madeira, hostplants were found in two locations, while monarchs were common and widespread. In the Azores, small hostplant patches were observed on four of seven surveyed islands, whereas monarchs were rare and restricted to two islands. Abandoned/semi-abandoned orange orchards represent the butterfly’s stronghold in Portugal, with the species being increasingly scarce along rivers and road verges where hostplants are declining. Hostplant persistence is unstable, with many patches removed, while others have expanded or colonised new areas. Overall, hostplants appear to be declining, with implications for the persistence of monarch butterflies in the country.

Arthropod declines have been linked to agricultural intensification. However, information about the impacts of intensification is still limited for many crops, as is our understanding of the responses of different arthropod taxa and trophic groups, thus hindering the development of effective mitigation measures. We investigated the impacts of olive farming intensification on canopy-dwelling arthropods in the Mediterranean region. Intensification involves the increased use of agrochemicals, mechanisation and irrigation, but also structural changes from traditional orchards with low densities of large and old trees, to intensive and superintensive orchards with high to very high densities of smaller and younger trees, respectively. Canopy arthropods were vacuum-sampled at 53 sites representing the three orchard intensification levels, in spring, summer and autumn 2017. We evaluated how the arthropod community varied across intensification levels, and in response to orchard structure, management and landscape context. We found no changes in the diversity of arthropod taxa across intensification levels after correcting for sample coverage, but arthropod abundance declined markedly along the intensification gradient. Decreased abundance was associated with changes in orchard structure, lower herbaceous cover, and higher herbicide and insecticide use. The abundance of a specialized olive pest was lower in landscapes with higher woodland cover. The negative effects of intensification were stronger in spring and summer than in autumn, and parasitoids and predators were particularly affected. Overall, results suggest that retaining herbaceous cover, reducing agrochemical inputs and preserving natural woody elements in the landscape, may contribute to mitigate impacts of olive farming intensification on canopy arthropods, particularly on beneficial species.

Agricultural policies in the European Union (EU) are increasingly promoting organic management and integrated pest management (IPM) as environmentally friendly alternatives to high-input conventional management. While there is consensus that organic management is largely beneficial for biodiversity, including the natural enemies of crop pests, IPM has been much less scrutinized. We conducted a meta-analysis based on 294 observations extracted from 18 studies to compare the effects of conventional, IPM and organic management on biocontrol potential and herbivore pressure in olive, an important cash crop in the EU. Information about the management practices used was also compiled to assess differences in intensity between the three management strategies. Results suggest that IPM is predominantly based on intensive practices, employing chemical control rather than preventive measures as a first resort. Biocontrol potential and herbivore pressure were similar in conventional management and IPM. Moreover, biocontrol potential was higher in organic crops than in crops under IPM, especially when considering canopy-dwelling natural enemies. Although organic management enhanced biocontrol potential, it also benefitted some olive pests, and in both cases effects were more pronounced at warmer temperatures. Our results suggest that, in its current form, IPM might not significantly affect biocontrol potential or herbivore pressure when compared with conventional olive crop management. A shift to a more comprehensive implementation of IPM practices is thus needed, involving the use of proactive measures to promote natural enemies and regulate olive pests before resorting to chemical control. Moreover, greater use of non-chemical inputs might be required for effective regulation of olive pests in organic olive crops.

Large scale afforestation (i.e., establishment of forests on farmland, grassland and other land not previously forested) is increasingly regarded as a cost-effective option to mitigate climate change by promoting carbon sequestration. However, this strategy can have negative biodiversity impacts, potentially causing the loss and fragmentation of open habitats of conservation value, as well as edge effects that can extend well beyond forest boundaries. Mitigating impacts of afforestation programs thus requires a detailed understanding of the mechanisms whereby they affect biodiversity, particularly where new plantations are established close to areas important for open habitat species. Here, we examined how afforestation with oak, pine or eucalyptus trees, commonly planted in Mediterranean Europe, may have distinct effects on nest predation risk of grassland birds in southern Portugal. We used artificial nests with quail eggs and camera traps to: (i) identify nest predators and estimate predation risk of ground-nesting birds in grasslands adjacent to oak, pine and eucalyptus plantations across a distance gradient (0 m to 300 m) from the plantation edge; and (ii) examine how predation risk was influenced by avian predator abundance, sward height and vegetation clearing for photo monitoring (nest-site manipulation), and their interactions with plantation type. Carrion crow was by far the main egg predator identified, followed by Montagu's harrier, raven and magpie. Overall, nest predation risk and predator abundance were higher around eucalyptus plantations, compared to either pine or oak plantations. Predation decreased with increasing sward height, but this effect was less noticeable when vegetation around nests was cleared. In pine and oak plantations, predation risk was slightly higher close to edges, and decreased with distance from the edge. Conversely, in eucalyptus plantations predation was lower close to edges, and increased with distance to edges. Distance effects around eucalyptus plantation were, however, absent in manipulated nests. Overall, results show that afforestation with different tree species has distinct impacts on predation risk of artificial nests in Mediterranean farmland. This is probably a consequence of an increasing structural complexity of the plantations, from oak to eucalyptus, driven by differences in tree growth rates and undergrowth cover. These findings suggest that farmland afforestation should favour agro-forest plantations with slow growing species (oak and pine) to mitigate negative effects on breeding grassland birds in adjacent open habitats.

Pest control services provided by naturally occurring species (the so-called biocontrol services) are widely recognized to provide key incentives for biodiversity conservation. This is particularly relevant for vertebrate-mediated biocontrol services as many vertebrate species are of conservation concern, with most of their decline associated to landscape modification for agricultural purposes. Yet, we still lack rigorous approaches evaluating landscape-level correlates of biocontrol potential by vertebrates over broad spatial extents to better inform land-use and management decisions. We performed a spatially-explicit interaction-based assessment of potential biocontrol services in Portugal, using 1853 pairwise trophic interactions between 78 flying vertebrate species (birds and bats) and 53 insect pests associated to two widespread and economically valuable crops in the Euro-Mediterranean region, olive groves (Olea europaea subsp. europaea) and vineyards (Vitis vinifera subsp. vinifera). The study area was framed using 1004 square cells, each 10 × 10 km in size. Potential biocontrol services were determined at all those 10 × 10 km grid-cells in which each crop was present as the proportion of the realized out of all potential pairwise interactions between vertebrates and pests. Landscape correlates of biocontrol potential were also explored. Our work suggests that both birds and bats can effectively provide biocontrol services in olive groves and vineyards as they prey many insect pest species associated to both crops. Moreover, it demonstrates that these potential services are impacted by landscape-scale features and that this impact is consistent when evaluated over broad spatial extents. Thus, biocontrol potential by vertebrates significantly increases with increasing amount of natural area, while decreases with increasing area devoted to target crops, particularly olive groves. Overall, our study highlights the suitability of our interaction-based approach to perform spatially-explicit assessments of potential biocontrol services by vertebrates at local spatial scales and suggest its utility for integrating biodiversity and ecosystem services in conservation planning over broad spatial extents.

Large-scale afforestation of agricultural land was carried out in the 1990s under the Common Agricultural Policy of the European Union. This policy aimed at delivering environmental benefits, among them positive biodiversity effects. However, knowledge of the long-term biodiversity impacts of these afforestation schemes remains very limited, particularly for insects. We provide a case study examining the biodiversity impacts of afforestation carried out in Mediterranean grasslands in southern Portugal. We sampled orthopterans and butterflies in native oak and pine plantations established under EEC regulation 2080/92, and in older exotic eucalyptus plantations. Sampling was also conducted in grassland habitats (permanent pastures and fallow land) adjacent to each plantation, and at plantation-grassland edges. In general, plantations supported lower orthopteran species richness and fewer orthopterans of conservation value than grassland and edges, particularly for eucalyptus plantations. Conversely, plantations were of higher conservation value for butterflies, and edges supported the highest butterfly richness. Plantations hosted some orthopteran and butterfly species that did not occur in grasslands, and so contributed to increase species richness at the landscape scale. Overall, results underline the importance of grassland, especially for orthopterans, and show that native plantations and associated edges can also provide habitat for species of conservation value. Therefore, retaining large grassland tracts and planting native rather than exotic tree species might minimize the negative effects of plantations for insect biodiversity in Mediterranean grassland. Overall, findings show that agricultural policy decisions can have protracted implications for biodiversity, thereby requiring long term environmental assessments and monitoring.

The distribution of butterfly species is limited by availability of larval host plants growing in suitable climatic conditions. The Two-tailed Pasha, Charaxesjasius (Linnaeus, 1767), is a Mediterranean butterfly with only sporadic historical records in Madrid, Spain’s most central province, where the host plant is uncommon and winters are colder than in most parts of the butterfly’s range. We show the first evidence of juvenile stages of the species in two towns of north-central Madrid and compile records of C.jasius from Madrid over the past four decades. Our results suggest that, in the absence of widespread host plants, C.jasius is using suburban ornamental plantings of its host plant to colonise a region which may be becoming more climatically suitable.

Crop production intensification often leads to the structural simplification of production systems. This structural simplification is expected to have strong impacts on biodiversity and the provisioning of ecosystem services, but information about this topic is scarce. For instance, no information exists for Mediterranean olive (Olea europaea) groves, despite olive farming representing a significant share of the agricultural sector in some European countries. We investigated the impact of in-farm and landscape-level structural simplification on the potential of three common insectivorous bats (i.e., Pipistrellus kuhlii, P. pygmaeus and P. pipistrellus) to provide biocontrol services against one of the most harmful olive pests worldwide, the olive fruit moth Prays oleae. Bats and insect surveys were both carried out in olive groves representing increasing levels of structural simplification and during three sampling seasons (spring, summer and autumn). At grove-level, structural simplification was considered as resulting from reduced planting pattern variability (i.e., tree and row spacing) and tree features (diameter at breast height, height of the trunk and canopy area), while at landscape level was considered as resulting from reduced land-cover types. We found that the Kuhl's pipistrelle was the most frequently recorded species in all types of olive groves and seasons. Moreover, the activity levels of pipistrelle bats as a whole significantly decreased with the structural simplification of olive groves. The abundance of P. oleae was highest at intermediate levels of structural simplification, irrespective of the season. Forest cover in the surrounding landscape had a significant positive influence on the activity levels of P. kuhlii, and a significant and negative influence on the abundance of P. oleae. Our study demonstrates that structural simplification differentially influences the activity patterns of both insectivorous bats and insect pests within olive groves. Moreover, it suggests that structural simplification may strongly compromise biocontrol services provided by bats on the major olive pest P. oleae.

One new subspecies of Sevenia amulia (Cramer, 1777) (Nymphalidae, Biblidinae) is described from Príncipe Island and compared with the previously known subspecies. Two faunistic novelties are reported from São Tomé Island and for the country: one species of Lycaenidae (Polyommatinae), another of Nymphalidae (Heliconiinae). The presence on Príncipe Island of another species, an endemic Hesperiidae (Hesperiinae) not reported from the country for almost a century, is confirmed and commented.

Se estudian unas muestras de mariposas angolanas del género Precis Hübner, 1819. Se describe una especie nueva, P. larseni Mendes, Bivar-de-Sousa, Vasconcelos & Lopes, sp. n., de las provincias de Moxico, Cuanza Norte y Huambo. Se apunta P. rauana como una novedad faunística para el país basándose en ejemplares de la provincia de Uige. Se presentan nuevos datos con relación a las otras especies del género ya conocidas de Angola.