The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Combined effects of agrochemicals and ecosystem services on crop yield across Europe

Simultaneously enhancing ecosystem services provided by biodiversity below and above ground is recommended to reduce dependence on chemical pesticides and mineral fertilisers in agriculture. However, consequences for crop yield have been poorly evaluated. Above ground, increased landscape complexity is assumed to enhance biological pest control, whereas below ground, soil organic carbon is a proxy for several yield-supporting services. In a field experiment replicated in 114 fields across Europe, we found that fertilisation had the strongest positive effect on yield, but hindered simultaneous harnessing of below- and above-ground ecosystem services. We furthermore show that enhancing natural enemies and pest control through increasing landscape complexity can prove disappointing in fields with low soil services or in intensively cropped regions. Thus, understanding ecological interdependences between land use, ecosystem services and yield is necessary to promote more environmentally friendly farming by identifying situations where ecosystem services are maximised and agrochemical inputs can be reduced.

Are both notes of the common cuckoo's call necessary for familiarity recognition?

Common cuckoos (Cuculus canorus) are best known for their simple two-note calls ("cu-coo"), which are uttered only by males during the breeding season. A previous playback study revealed that territorial males were more tolerant toward playbacks of the calls of familiar, neighbouring individuals than toward unfamiliar, stranger simulated intruders, exhibiting the classical "dear-enemy" phenomenon. Here we experimentally assessed whether the acoustic cues for familiarity recognition are encoded in the first and/or second note of these simple calls. To do so, we played mixed sound files to radio-tagged cuckoos, where the first part of the two-note calls was taken from strangers and the second part from neighbours, or vice versa. As controls, we used behavioural data from two-note neighbour and two-note stranger call playbacks. Cuckoos responded consistently to the two types of mixed sound files. When either the first or second note of the call was taken from a stranger and the other note from a neighbour, they responded to these sound files similarly to two-note playbacks of strangers: they approached the speaker of the playbacks more closely and the calling response-latency to playbacks was longer than to familiar controls. These findings point to the importance of both notes in familiarity recognition. We conclude that familiarity recognition in male common cuckoos needs the complete structure of the two-note cuckoo call, which is characteristic for this species.

Farmland biodiversity and agricultural management on 237 farms in 13 European and two African regions

Farmland is a major land cover type in Europe and Africa and provides habitat for numerous species. The severe decline in farmland biodiversity of the last decades has been attributed to changes in farming practices, and organic and low-input farming are assumed to mitigate detrimental effects of agricultural intensification on biodiversity. Since the farm enterprise is the primary unit of agricultural decision making, management-related effects at the field scale need to be assessed at the farm level. Therefore, in this study, data were collected on habitat characteristics, vascular plant, earthworm, spider, and bee communities and on the corresponding agricultural management in 237 farms in 13 European and two African regions. In 15 environmental and agricultural homogeneous regions, 6-20 farms with the same farm type (e.g., arable crops, grassland, or specific permanent crops) were selected. If available, an equal number of organic and non-organic farms were randomly selected. Alternatively, farms were sampled along a gradient of management intensity. For all selected farms, the entire farmed area was mapped, which resulted in total in the mapping of 11 338 units attributed to 194 standardized habitat types, provided together with additional descriptors. On each farm, one site per available habitat type was randomly selected for species diversity investigations. Species were sampled on 2115 sites and identified to the species level by expert taxonomists. Species lists and abundance estimates are provided for each site and sampling date (one date for plants and earthworms, three dates for spiders and bees). In addition, farmers provided information about their management practices in face-to-face interviews following a standardized questionnaire. Farm management indicators for each farm are available (e.g., nitrogen input, pesticide applications, or energy input). Analyses revealed a positive effect of unproductive areas and a negative effect of intensive management on biodiversity. Communities of the four taxonomic groups strongly differed in their response to habitat characteristics, agricultural management, and regional circumstances. The data has potential for further insights into interactions of farmland biodiversity and agricultural management at site, farm, and regional scale.

Climate-induced phenological shift of apple trees has diverse effects on pollinators, herbivores and natural enemies

Climate change is altering the phenology of trophically linked organisms, leading to increased asynchrony between species with unknown consequences for ecosystem services. Although phenological mismatches are reported from several ecosystems, experimental evidence for altering multiple ecosystem services is hardly available. We examined how the phenological shift of apple trees affected the abundance and diversity of pollinators, generalist and specialist herbivores and predatory arthropods. We stored potted apple trees in the greenhouse or cold store in early spring before transferring them into orchards to cause mismatches and sampled arthropods on the trees repeatedly. Assemblages of pollinators on the manipulated and control trees differed markedly, but their overall abundance was similar indicating a potential insurance effect of wild bee diversity to ensure fruit set in flower-pollinator mismatch conditions. Specialized herbivores were almost absent from manipulated trees, while less-specialized ones showed diverse responses, confirming the expectation that more specialized interactions are more vulnerable to phenological mismatch. Natural enemies also responded to shifted apple tree phenology and the abundance of their prey. While arthropod abundances either declined or increased, species diversity tended to be lower on apple trees with shifted phenology. Our study indicates novel results on the role of biodiversity and specialization in plant-insect mismatch situations.

Insect morphometry is reproducible under average investigation standards

Morphometric research is being applied to a growing number and variety of organisms. Discoveries achieved via morphometric approaches are often considered highly transferable, in contrast to the tacit and idiosyncratic interpretation of discrete character states. The reliability of morphometric workflows in insect systematics has never been a subject of focused research, but such studies are sorely needed. In this paper, we assess the reproducibility of morphometric studies of ants where the mode of data collection is a shared routine.We compared datasets generated by eleven independent gaugers, that is, collaborators, who measured 21 continuous morphometric traits on the same pool of individuals according to the same protocol. The gaugers possessed a wide range of morphometric skills, had varying expertise among insect groups, and differed in their facility with measuring equipment. We used intraclass correlation coefficients (ICC) to calculate repeatability and reproducibility values (i.e., intra- and intergauger agreements), and we performed a multivariate permutational multivariate analysis of variance (PERMANOVA) using the Morosita index of dissimilarity with 9,999 iterations.The calculated average measure of intraclass correlation coefficients of different gaugers ranged from R = 0.784 to R = 0.9897 and a significant correlation was found between the repeatability and the morphometric skills of gaugers (p = 0.016). There was no significant association with the magnification of the equipment in the case of these rather small ants. The intergauger agreement, that is the reproducibility, varied between R = 0.872 and R = 0.471 (mean R = 0.690), but all gaugers arrived at the same two-species conclusion. A PERMANOVA test revealed no significant gauger effect on species identity (R 2 = 0.69, p = 0.58).Our findings show that morphometric studies are reproducible when observers follow the standard protocol; hence, morphometric findings are widely transferable and will remain a valuable data source for alpha taxonomy.

Common cuckoos (Cuculus canorus) affect the bacterial diversity of the eggshells of their great reed warbler (Acrocephalus arundinaceus) hosts

The common cuckoo (Cuculus canorus) is an avian brood parasite, laying its eggs in the nests of other bird species, where these hosts incubate the parasitic eggs, feed and rear the nestlings. The appearance of a cuckoo egg in a host nest may change the bacterial community in the nest. This may have consequences on the hatchability of host eggs, even when hosts reject the parasitic egg, typically within six days after parasitism. The present study revealed the bacterial community of cuckoo eggshells and those of the great reed warbler (Acrocephalus arundinaceus), one of the main hosts of cuckoos. We compared host eggs from non-parasitized clutches, as well as host and cuckoo eggs from parasitized clutches. As incubation may change bacterial assemblages on eggshells, we compared these egg types in two stages: the egg-laying stage, when incubation has not been started, and the mid-incubation stage (ca. on days 5–7 in incubation), where heat from the incubating female dries eggshells. Our results obtained by the 16S rRNA gene sequencing technique showed that fresh host and cuckoo eggs had partially different bacterial communities, but they became more similar during incubation in parasitized nests. Cluster analysis revealed that fresh cuckoo eggs and incubated host eggs in unparasitized nests (where no cuckoo effect could have happened) were the most dissimilar from the other groups of eggs. Cuckoo eggs did not reduce the hatchability of great reed warbler eggs. Our results on the cuckoo-great reed warbler relationship supported the idea that brood parasites may change bacterial microbiota in the host nest. Further studies should reveal how bacterial communities of cuckoo eggshells may vary by host-specific races (gentes) of cuckoos.

Individual movement of large carabids as a link for activity density patterns in various forestry treatments

Activity density is one of the most common measures for ground-dwelling arthropods including carabids. The term refers to the empirical fact that pitfall trap catches depend on the individuals’ activity; the higher activity of the individuals, the more catches in the traps. Although the movement at the individual level is widely studied, there is no available evidence whether the individual movement can be a good proxy for activity density. In our study, we aimed to explore this link in two ground beetle species, Carabus scheidleri and C. coriaceus, in oak-hornbeam forest in Hungary. We used pitfall traps for activity density and capture-mark-recapture and radio telemetry to record individual movement patterns in different forestry treatments, preparation cuttings and clear-cuttings, and their control plots. We identified an indirect link between activity density and movement of individuals via treatment types. Although activity density, mean walking speed, and the proportion of active time were significantly higher in both treatments than in control plots, individual movement reveals only temporal use of these habitats. Beetles left treatments within a few days. We concluded that the high turnover of individuals in treatments might indirectly suggest that these habitats likely act as temporary foraging sites for both species.

Mixed effects of ecological intensification on natural pest control providers: a short-term study for biotic homogenization in winter wheat fields

Agricultural intensification is one of the major drivers of biotic homogenization and has multiple levels ranging from within-field management intensity to landscape-scale simplification. The enhancement of invertebrate assemblages by establishing new, semi-natural habitats, such as set-aside fields can improve biological pest control in adjacent crops, and mitigate the adverse effect of biotic homogenization. In this study we aimed to examine the effects of ecological intensification in winter wheat fields in Hungary. We tested how pests and their natural enemies were affected at different spatial scales by landscape composition (proportion of semi-natural habitats in the surrounding matrix), configuration (presence of adjacent set-aside fields), and local field management practices, such as fertilizer (NPK) applications without applying insecticides. We demonstrated that at the local scale, decreased fertilizer usage had no direct effect either on pests or their natural enemies. Higher landscape complexity and adjacent semi-natural habitats seem to be the major drivers of decreasing aphid abundance, suggesting that these enhanced the predatory insect assemblages. Additionally, the high yield in plots with no adjacent set-aside fields suggests that intensive management can compensate for the lower yields on the extensive plots. Our results demonstrated that although complexity at the landscape scale was crucial for maintaining invertebrate assemblages, divergence in their response to pests and pathogens could also be explained by different dispersal abilities. Although the landscape attributes acted as dispersal filters in the organization of pest and pathogen assemblages in croplands, the presence of set-aside fields negatively influenced aphid abundance due to their between-field isolation effect.

Recording fine-scale movement of ground beetles by two methods: Potentials and methodological pitfalls

Movement trajectories are usually recorded as a sequence of discrete movement events described by two parameters: step length (distance) and turning angle (bearing). One of the most widespread methods to record the geocoordinates of each step is by a GPS device. Such devices have limited suitability for recording fine movements of species with low dispersal ability including flightless carabid beetles at small spatio-temporal scales. As an alternative, the distance-bearing approach can avoid the measurement error of GPS units since it uses directly measured distances and compass azimuths. As no quantification of measurement error between distance-bearing and GPS approaches exists so far, we generated artificial fine-scale trajectories and in addition radio-tracked living carabids in a temperate forest and recorded each movement step by both methods. Trajectories obtained from distance-bearing were compared to those obtained by a GPS device in terms of movement parameters. Consequently, both types of trajectories were segmented by state-switching modeling into two distinct movement stages typical for carabids: random walk and directed movement. We found that the measurement error of GPS compared to distance-bearing was 1.878 m (SEM = 0.181 m) for distances and 31.330° (SEM = 2.066°) for bearings. Moreover, these errors increased under dense forest canopy and rainy weather. Distance error did not change with increasing distance recorded by distance-bearing but bearings were significantly more sensitive to error at short distances. State-switching models showed only slight, not significant, differences in movement states between the two methods in favor of the random walk in the distance-bearing approach. However, the shape of the GPS-measured trajectories considerably differed from those recorded by distance-bearing caused especially by bearing error at short distances. Our study showed that distance-bearing could be more appropriate for recording movement steps not only of ground-dwelling beetles but also other small animals at fine spatio-temporal scales.