Increasing Plant Species Richness Research Articles

Effects of species diversity on trait expression of the clonal herb Taraxacum officinale and its relation to genotype diversity and phenotypic plasticity.

Plant species respond to varying plant species diversity and associated changes in their abiotic and biotic environment with changes in their phenotype. However, it is not clear to what degree this phenotypic differentiation is due to genotype diversity within populations or phenotypic plasticity of plant individuals. We studied individuals of 16 populations of the clonal herb Taraxacum officinale grown in plant communities of different species richness in a 17-year-old grassland biodiversity experiment (Jena Experiment). We collected 12 individuals in each population to measure phenotypic traits and identify distinct genotypes using microsatellite DNA markers. Plant species richness did not influence population-level genotype and trait diversity. However, it affected the expression of several phenotypic traits, e.g. leaf and inflorescence number, maximum leaf length and seed mass, which increased with increasing plant species richness. Moreover, population-level trait diversity correlated positively with genotype richness for leaf dry matter content (LDMC) and negatively with inflorescence number. For several traits (i.e. seed mass, germination rate, LDMC, specific leaf area (SLA)), a larger portion of variance was explained by genotype identity, while variance in other traits (i.e. number of inflorescences, leaf nitrogen concentration, leaf number, leaf length) resided within genotypes and thus was mostly due to phenotypic plasticity. Overall, our findings show that plant species richness positively affected the population means of some traits related to whole-plant performance, whose variation was achieved through both phenotypic plasticity and genotype composition of a population.

Sensitivity to agricultural inputs and dispersal limitation determine the response of arable plants to time since transition to organic farming

Abstract Transitioning to low‐input agricultural systems such as organic farming has been acknowledged as a way to mitigate negative effects of agriculture on biodiversity. However, the speed, magnitude and context dependence of biodiversity recovery after converting to organic farming remain uncertain. In this study, we explored the response of plant communities to time since transition to organic farming in a variety of production contexts. Using a spatially replicated space‐for‐time substitution design, we surveyed plant communities in small‐grain cereal and ley fields in conventional and organic farms, distributed along independent gradients of time since transition to organic farming and proportion of seminatural grasslands in the landscapes. We selected a set of response traits to explore the mechanism of potential time lag in that response to conversion. These traits were selected to characterize the sensitivity of plant species to agricultural inputs and their ability to respond swiftly to environmental changes. We found an increase in plant species richness and evenness in cereal fields with increasing time since transition to organic farming, and a similar but less pronounced pattern in leys. After 30 years of continuous organic farming, organic cereal fields harboured more than twice the number of plant species than newly converted fields. Importantly, we found that the dependence on insect pollination, sensitivity to herbicides and dispersal capacity of plants modulated the effects of time since transition on plant communities in cereal fields. This suggests that both management and biotic interactions shape plant community structure in response to organic practices over time. Policy implications. Our study highlights that benefits of organic farming for plant diversity are likely to take decades to become substantial after conversion. We found this slow recovery of plant communities to be driven by both the gradual improvement of habitat quality after conversion and species' dispersal limitation. Assessments of biodiversity benefits of organic farming should therefore consider this time delay to avoid underestimating its environmental performance. Farmers should also be supported during this ecological transitional phase during which yield‐enhancing ecosystem services reliant on plant diversity might build up.

The interplay between defaunation and phylogenetic diversity affects leaf damage by natural enemies in tropical plants

Abstract Natural enemies play an important role in controlling plant population growth and vegetation dynamics. Tropical rainforests host the greatest diversity of herbivores, from large mammalian ungulates to microscopic pathogens, generating and maintaining plant diversity. By feeding on the same resources, large mammalian herbivores may interfere with plant consumption and leaf damage by important enemy guilds such as invertebrate herbivores and pathogens, triggering indirect trophic cascades. However, the impact of local extinctions of large herbivores on plant–enemy interactions is relatively unknown. We experimentally tested the effects of defaunation of large mammalian herbivores (e.g. peccaries, tapirs and brocket deer; hereafter, large herbivores) on the leaf damage of 3350 understorey plants in tropical rainforests of Brazil. We examined leaf damage in 10,050 leaves from 333 morphospecies by assigning the area consumed or damaged by five guilds of insect herbivores and leaf pathogens within 86 paired open‐closed plots and investigating the joint effects of defaunation and plant phylogenetic diversity. Plants released from large herbivores had 9% less leaf damage; this difference was due to the lower leaf pathogens incidence (29%) rather than insect herbivory. Evolutionary distinctness was positively correlated with leaf damage in a similar way in all treatments, suggesting additive effects of defaunation and phylogenetic diversity. Total and pathogenic leaf damage (but not insect damage) decreased with plant richness across treatments, and large herbivores exclusion resulted in increased plant species richness. This suggests that large herbivores exclusion leads to a dilution of total and pathogens' leaf damage by increasing plant species richness. Our results suggest that indirect effects of large herbivores decrease the dilution potential of plant communities against pathogens and rather reinforce their top‐down impact on vegetation, demonstrating a previously overlooked cascading effect of large herbivore extinction on forest ecosystems. Synthesis: The extinction of large mammalian herbivores can lead to a decrease in pathogen‐driven leaf damage, a previously unknown indirect effect in forest ecosystems, which might have consequences for plant fitness and ultimately for plant diversity. Large herbivores and plant pathogens might have synergistic effects in regulating the diversity of plant communities in some of the most diverse ecosystems on Earth.

The seeds of Plantago lanceolata comprise a stable core microbiome along a plant richness gradient

BackgroundSeed endophytic bacteria are beneficial to plants. They improve seedling growth by enhancing plant nutrient uptake, modulating stress-related phytohormone production, and targeting pests and pathogens with antibiotics. Seed endophyte composition can be influenced by pollination, plant cultivar, and soil physicochemical conditions. However, the effects of plant community richness on seed endophytes are unknown. To investigate the effects of increasing plant species richness on the diversity and composition of the seed microbiome, we made use of a well-established long-term biodiversity experiment in Germany (The Jena Experiment). We sampled seeds from different Plantago lanceolata blossoms in a plant diversity gradient ranging from monoculture to 16 species mixtures. The seeds were surface sterilized to remove seed surface-associated bacteria and subjected to a metabarcoding approach to assess bacterial community structure.ResultsOur data indicate a very stable core microbiome, which accounted for more than 90% of the reads and was present in all seeds independent of the plant richness level the seeds originated from. It consisted mainly of reads linked to Pseudomonas rhizosphaerae, Sphingomonas faeni and Pirellulla spp. 9% of the obtained reads were not part of the core microbiome and were only present in plots of specific diversity levels. The number of unique ASVs was positively correlated with plant richness. Interestingly, most reads described as non-core members belonged to the same genera described as the core microbiome, indicating the presence of different strains or species with possibly different functional properties important for seed performance.ConclusionOur data indicate that Plantago lanceolata maintains a large seeds core microbiome across the plant richness gradient. However, the number of unique ASVs increases alongside the plant community richness, indicating that ecosystem biodiversity also mitigates diversity loss in seed endophytes.

Plant invasion and fragmentation indirectly and contrastingly affect native plants and grassland arthropods

Plant invasion and habitat fragmentation have a detrimental effect on biodiversity in nearly all types of ecosystems. We compared the direct and indirect effects of the invasion of the common milkweed (Asclepias syriaca) on biodiversity patterns in different-sized Hungarian forest-steppe fragments. We assessed vegetation structure, measured temperature and soil moisture, and studied organisms with different ecological roles in invaded and non-invaded sites of fragments: plants, bees, butterflies, flower-visiting wasps, flies, true bugs, and spiders. Temperature and soil moisture were lower in invaded than in non-invaded area. Milkweed had a positive effect on plant species richness and flower abundance. In contrast, we mainly found indirect effects of invasion on arthropods through alteration of physical habitat characteristics and food resources. Pollinators were positively affected by native flowers, thus, milkweed indirectly supported pollinators. Similarly, we found higher species richness of herbivores in invaded sites than control sites, as species richness of true bugs also increased with increasing plant species richness. Predators were positively affected by complex vegetation structure, higher soil moisture and lower temperature. Furthermore, increasing fragment size had a strong negative effect on spider species richness of non-invaded sites, but no effect in invaded sites. Especially, grassland specialist spiders were more sensitive to fragment size than generalists, whereas generalist spider species rather profited from invasion. Although milkweed invades natural areas, we did not identify strong negative effects of its presence on the diversity of the grassland biota. However, the supportive effect of milkweed on a few generalist species homogenises the communities. The rate of invasion might increase with increasing fragmentation, therefore we recommend eliminating invasive plants from small habitat fragments to preserve the native biota. Focusing also on generalist species and revealing the indirect effects of invasions are essential for understanding the invasion mechanisms and would support restoration efforts.

Anthropocene trajectories of high alpine vegetation on Mont-Blanc nunataks

ABSTRACT Climate warming causes dramatic glacier retreat and intense vegetation changes in alpine regions. High-elevation nunataks, that is bedrock islands protruding from glaciers with uppermost flowering plants, are no exception. Yet the consequences of climate change on nunatak vegetation remain relatively unexplored. Here, we report findings from a re-visit of historical plant surveys carried out on six nunataks situated between 2180 m a.s.l. and 3509 m a.s.l. amidst the glaciers of the Mont-Blanc range (France). We compared vegetation surveys conducted in 2020 to those made 150 years before, and performed remote sensing analyses to depict changes in vegetation productivity during recent decades. We report an increase in plant species richness for the lowest and least isolated nunataks, which contributed to a strong signal of vegetation greening over the last 35 years. This trend was due to the upward migration of competitive species, but also due to species colonization from neighboring high alpine areas into recently unglaciated microsites. We also highlight striking ecological trajectories that have been little discussed so far, such as stable vegetation composition in the highest and most isolated nunataks, an increase of plant species associated with non-permanent snow-cover and water run-off, an increase of graminoids at lower elevations, and of phanerophytes at higher elevations. We argue that high alpine vegetation changes are not driven by the sole upward migration of lowland competitive species, and that careful monitoring of ongoing ecological changes over broad elevation gradients is necessary to better understand the rapid transformation of high alpine landscapes.

Increasing plant species richness by seeding has marginal effects on ecosystem functioning in agricultural grasslands

Abstract Experimental evidence shows that grassland plant diversity enhances ecosystem functioning. Yet, the transfer of results from controlled biodiversity experiments to naturally assembled ‘real world’ ecosystems remains challenging due to environmental variation among sites, confounding biodiversity ecosystem functioning relations in observational studies. To bridge the gap between classical biodiversity‐ecosystem functioning experiments and observational studies of naturally assembled and managed ecosystems, we created regionally replicated, within‐site gradients of species richness by seeding across agricultural grasslands differing in land‐use intensity (LUI) and abiotic site conditions. Within each of 73 grassland sites, we established a full‐factorial experiment with high‐diversity seeding and topsoil disturbance and measured 12 ecosystem functions related to productivity, and carbon and nutrient cycling after 4 years. We then analysed the effects of plant diversity (seeded richness as well as realized richness), functional community composition, land use and abiotic conditions on the ecosystem functions within (local scale) as well as among grassland sites (landscape scale). Despite the successful creation of a within‐site gradient in plant diversity (average increase in species richness in seeding treatments by 10%–35%), we found that only one to two of the 12 ecosystem functions responded to realized species richness, resulting in more closed nitrogen cycles in more diverse plant communities. Similar results were found when analysing the effect of the seeding treatment instead of realized species richness. Among sites, ecosystem functioning was mostly driven by environmental conditions and LUI. Also here, the only functions related to plant species richness were those associated with a more closed nitrogen cycle under increased diversity. The minor effects of species enrichment we found suggest that the functionally‐relevant niche space is largely saturated in naturally assembled grasslands, and that competitive, high‐functioning species are already present. Synthesis: While nature conservation and cultural ecosystem services can certainly benefit from plant species enrichment, our study indicates that restoration of plant diversity in naturally assembled communities may deliver only relatively weak increases in ecosystem functioning, such as a more closed nitrogen cycle, within the extensively to moderate intensively managed agricultural grasslands of our study.

Developing perennial wildflower strips for use in Mediterranean orchard systems.

To support sustainable food production and the delivery of ecosystem services through ecological intensification, wildflower strips have become a popular strategy. Despite their success in temperate orchard systems, they remain understudied in Mediterranean ecosystems, which poses a significant barrier to uptake. In order to further promote their adoption, seed mixes must be optimised for commercial orchard systems and for the Mediterranean climate. Plant species should be selected for their consistent performance, whilst the availability of resources for ecosystem service providers determines the quality of the wildflower strip. In this study, the suitability of 12 native perennial forbs and two tussock-forming grass species for wildflower strips in commercial Citrus orchards was assessed over a 3-year period. Distinct resources for natural enemies according to the different plant growth stages were used an indicator of wildflower strip quality. The wildflower strips were managed under two different cutting strategies: (i) standard management, in which wildflower strips were cut once annually in February, and (ii) active management, in which wildflower strips were cut two additional times each year. The establishment and success of the sown species were compared. The influence of wildflower strips and their management on plant species richness, community structure, and the provision of resources was compared with a control treatment, in which alleyways were managed conventionally by cutting any naturally occurring vegetation to a height of ≤5 cm, four to five times annual. For the first time, the performance of native perennial plant species has been assessed in Mediterranean orchard systems and a seed mix developed for targeting pest regulation services. The wildflower strips were successful in increasing plant species richness and the available resources expected to support natural enemies. However, only wildflower strips managed with cutting once annually enhanced vegetation cover relative to the control, whilst extending the flowering period. This study therefore provides crucial tools for the further development of sustainable approaches to food production in Mediterranean orchard systems.

Impacts of Climate Change and Human Activities on Plant Species α-Diversity across the Tibetan Grasslands

Plant species α-diversity is closely correlated with ecosystem structures and functions. However, whether climate change and human activities will reduce plant species α-diversity remains controversial. In this study, potential (i.e., potential species richness: SRp, Shannonp, Simpsonp and Pieloup) and actual plant species α-diversity (i.e., actual species richness: SRa, Shannona, Simpsona and Pieloua) during 2000–2020 were quantified based on random forests in grasslands on the Tibetan Plateau. Overall, climate change had positive influences on potential plant species α-diversity across all the grassland systems. However, more than one-third areas showed decreasing trends for potential plant species α-diversity. Climate change increased the SRp at rates of 0.0060 and 0.0025 yr−1 in alpine steppes and alpine meadows, respectively. Temperature change predominated the variations of Shannonp and Simpsonp, and radiation change predominated the variations of SRp and Pieloup. Geography position, local temperature, precipitation and radiation conditions regulated the impacts of climate change on potential species α-diversity. On average, human activities caused 1% plant species loss but elevated the Shannon, Simpson and Pielou by 26%, 4% and 5%, respectively. There were 46.51%, 81.08%, 61.26% and 61.10% areas showing positive effects of human activities on plant species richness, Shannon, Simpson and Pielou, respectively. There were less than 48% areas showing increasing trends of human activities’ impacts on plant species α-diversity. Human activities increased plant species richness by 2% in alpine meadows but decreased plant species richness by 1% in alpine steppes. Accordingly, both the impacts of climate change and human activities on plant species α-diversity were not always negative and varied with space and grassland types. The study warned that both climate change and human activities may not cause as much species loss as expected. This study also cautioned that the impacts of radiation change on plant species α-diversity should be at least put on the same level as the impacts of climate warming and precipitation change on plant α-diversity.

Understory plant growth forms respond independently to combined natural and anthropogenic disturbances

Natural disturbances can maintain forest diversity by creating a heterogeneous resource landscape, which can contribute to coexistence of early- and late-successional species. However, almost all forested ecosystems are also subject to multiple anthropogenic stressors, which could inhibit plant diversity and forest recovery after natural disturbances. Here, we present the first large-scale replicated field experiment testing the interactions among two natural and two anthropogenic disturbances in a mature secondary temperate forest. Specifically, we test the extent to which: 1. a natural windthrow (tornado), 2. deer browsing, 3. salvage logging, a common forestry practice to generate revenue after natural disturbances, and 4. mechanical removal of the understory, drive subsequent plant community assembly, diversity, and abundance. Our results have two clear messages. First, the combined disturbances, especially salvage logging, increased plant species richness and abundance; we found 65 more species in 0.1 ha of the disturbed areas versus the same area of reference forest. Second, we found that it was critical to analyze plant growth forms separately; each major plant growth form responded to the disturbances differently. Surprisingly, salvage logging, browsing, and vegetation removal had negligible effects on the diversity and abundance of tree seedlings or saplings. In contrast, salvaging increased herb richness by 30% (six extra species per 36 m2 plot), and shrubs were twice as abundant in salvaged versus unsalvaged plots. The combined disturbances created unique plant communities in comparison to adjacent undisturbed reference sites, but plant growth forms differed in which combination of disturbances shifted community composition the most. We did not find that non-native invasive species substantially increased in abundance in response to the disturbances, nor were invasive species unique to the salvaged areas. Together, our results demonstrate that a patchwork of combined natural and anthropogenic disturbances can promote plant diversity in a human-modified temperate forest. In particular, the combination of a natural wind disturbance and salvage logging benefited native herbaceous species, the plant group that represents the vast majority of vascular plant species (∼80%) in temperate forests across the world.

The relative effectiveness of different grassland restoration methods: A systematic literature search and meta‐analysis

Abstract Active grassland restoration has gained importance in mitigating the dramatic decline of farmnland biodiversity. While there is evidence that such operations are generally effective in promoting plant diversity, little is known about the effectiveness of the different methods applied. Restoration methods can differ in intensity of seed bed preparation, seed source and method of seed application. In this systematic literature search and meta‐analysis, we screened the literature for studies of the restoration of mesic grasslands in temperate Europe. We focused on active restoration experiments that included a treatment and lasted for more than 3 years. We evaluated the influence of restoration factors on plant species richness relative to non‐restored controls. We found 187 articles that investigated the outcome of operations aimed at actively restoring mesic temperate grasslands. Most articles focused on plants, with only 9.6% dealing with other organisms (e.g. beetles, pollinating insects). Many papers had to be excluded due to incomplete data, too short study duration and/or lack of an adequate control. This resulted in 13 articles fulfilling our criteria for inclusion, yielding a total of 56 data points for the meta‐analysis. Restoration actions increased plant species richness by, on average, 17.4%, compared to controls. The seed source explained a significant amount of variation in plant species richness: seeds originating from a speciose donor grassland had a positive effect. This effect was even enhanced when combined with a commercial seed mix, whereas commercial seed mixes alone had no significant effect. We did not observe any effect of other factors, such as the type of seed bed preparation or the seed application method. A seed‐source obtained from species‐rich grasslands seems to be key to efficient grassland restoration in mesic grasslands of temperate Europe. Even though seeds from a speciose donor grassland should be preferred over commercial seeds, associating natural and commercial seed mixes increases plant species richness. This systematic literature search further revealed two major research gaps in grassland restoration ecology: a deficit in long‐term investigations as well as a deficit in studies focusing on non‐plant organisms.

Contrasting effects of species richness on soil pollutant removal in herbaceous plant communities: the importance of individual species

Many studies have shown that increasing species diversity generally increases ecosystem functioning, but few have evaluated the role of species diversity in soil pollutant removal, especially for organic pollutants. We test the hypothesis that increasing plant diversity can enhance soil pollutant removal. To test the hypothesis, we conducted two experiments: one for removal of cadmium and the other for removal of cypermethrin from the soil. In both experiments, plants were grown in monocultures, four‐ and eight‐species mixtures in soils contaminated with the pollutants. Contaminated soils without plants were also included as controls. Our results showed that the efficiency of cadmium removal from the soil decreased with increasing plant species richness. The negative effect of diversity on cadmium removal was largely attributed to species underyielding in plant mixtures. In contrast, the efficiency of cypermethrin removal from soils increased with increasing plant species richness. The positive effect of diversity on cypermethrin removal was likely due to the presence of Taraxacum mongolicum which had the lowest biomass but the highest removal efficiency. Our results suggest that species diversity may regulate pollutant remediation, and this is pollutant‐dependent. Moreover, the performance of individual species can strongly influence the direction and magnitude of the diversity effect on soil pollutant removal. These species should be treated with cautious in the remediation of contaminated soils.

The key to temperate savanna restoration is to increase plant species richness reasonably

Changes in species composition and diversity-productivity relationships during vegetation succession are of great significance for the restoration of degraded grasslands. However, the human intervention of grassland restoration mostly considers the single ecological (diversity) or production (biomass) function of grasslands, and does not fully consider the relationships between the two to improve the restoration effects. In this study, three vegetation types (desert grassland, sandy grassland and temperate savanna) were considered to simulate the three stages of restoration of degraded temperate savanna (early, middle and late restoration). Changes in species composition, diversity, and diversity-productivity relationships during the temperate savanna restoration were explored through spatiotemporal substitution. The results showed that with the progress of succession, xerophytes decreased significantly, mesophytes and hygrophytes increased, C4 plants decreased gradually, and C3 plants increased. The change of species richness was the main reason for community differences in the process of community succession, and species replacement mainly occurred between communities in the early and middle stages of succession. Species richness increased significantly from early to late stage of restoration. Latitude was significantly negatively correlated with species diversity. In the process of vegetation restoration, the impact of species richness, Pielou’s evenness, and β-diversity on biomass gradually developed positively and continued to increase, while the Simpson index showed the opposite effect. This study provides references for the restoration of temperate savanna and emphasizes the ecological and productive functions of the grassland should be taken into account in the restoration strategy.

Ant and plant diversity respond differently to seed‐based prairie restoration

Recovering biodiversity is a common goal of restoration, yet outcomes for animal communities are highly variable. A major reason for this variability may be that active restoration efforts typically target plant communities, with the assumption that animal communities will passively recover in turn. However, this assumption remains largely unvalidated experimentally making it unclear how plant‐focused restoration strategies influence animal communities. We evaluated how the diversity of seed mixes used to restore tallgrass prairies (a common plant‐focused technique) influenced the recovery of ant community diversity and composition. Our study took place within a large‐scale restoration experiment in southwest Michigan, where 12 former agricultural fields are being restored to tallgrass prairie by sowing seeds of prairie plant species native to our region. Half of each field was seeded with 12 prairie species and the other half with 72 prairie species. Sites restored with high diversity seed mixes increased plant species richness, but did not consistently influence ant richness or community composition. Instead, ant species richness and composition were related to an interaction between realized plant species richness (which was only partly structured by seeding treatments) and environmental structure. Specifically, ant richness increased more with higher realized plant richness when vegetation cover was lower and soil‐surface temperatures were higher. Our findings illustrate how plant and animal communities can respond differently to plant‐focused restoration efforts. Despite this, plant community restoration can structure animal community responses, in concert with environmental factors. Layering additional restoration strategies onto existing plant‐focused approaches may further benefit biodiversity across taxa.

Plant diversity effects on herbivory are related to soil biodiversity and plant chemistry

Abstract Insect herbivory is a key process in ecosystem functioning. While theory predicts that plant diversity modulates herbivory, the mechanistic links remain unclear. We postulated that the plant metabolome mechanistically links plant diversity and herbivory. In late summer and in spring, we assessed individual plant above‐ground herbivory rates and metabolomes of seven plant species in experimental plant communities varying in plant species diversity and resource acquisition strategies. In the same communities, we also measured plant individual biomass as well as soil microbial and nematode community composition. Herbivory rates decreased with increasing plant species richness. Path modelling revealed that plant species richness and community resource acquisition strategy correlated with soil community composition. In particular, changes in nematode community composition were related to plant metabolome composition and thereby herbivory rates. Synthesis. These results suggest that soil community composition plays an important role in reducing herbivory rates with increasing plant diversity by changing plant metabolomes.

The activity of a subterranean small mammal alters Afroalpine vegetation patterns and is positively affected by livestock grazing

Subterranean rodents can act as ecosystem engineers by shaping the landscape due to soil perturbation and herbivory. At the same time, their burrow density is affected by environmental conditions, vegetation and anthropogenic factors. Disentangling this complex interplay between subterranean rodents and their environment remains challenging. In our study, we analysed the interplay of abiotic conditions, vegetation patterns and human land-use and the burrow density of the giant root-rat (GRR; Tachyoryctes macrocephalus), a subterranean rodent endemic to the Afroalpine ecosystem of the Bale Mountains in south-east Ethiopia. Specifically, we examined the effects of GRR on plant species richness and vegetation cover and vice-versa, and how these reciprocal effects might be modulated by temperature, habitat wetness and grazing. Our results showed that increasing GRR burrow density led to decreased vegetation cover, and that effects of GRR on vegetation cover were slightly stronger than vice-versa. Considering the reciprocal causation models, we found that increasing plant species richness led to increased GRR burrow density, while GRR burrow density decreased as vegetation cover increased. Increases in habitat wetness and livestock grazing intensity also directly led to increased GRR burrow density. Our results stress the importance of subterranean ecosystem engineers on vegetation and highlight the vulnerability of these complex interactions to human activity.

How do patch burnings affect ant communities and seed removal in a subtropical grassland?

Disturbances modify local abiotic properties, habitat structure and resource availability, shaping community assembly and ecological interactions. Open ecosystems have an evolutionary relationship with fire. We evaluated the effects of patch burnings on grassland ant communities and patterns of seed removal. We established 14 plots of 10 m2 in pairs in a disturbance-suppressed grassland in South Brazil. A random plot of each pair was burned, and another plot was the control. We accessed ant communities with pitfall-traps and sweeping net, and seed removal with seed traps in all plots prior the experimental fires, and then on three occasions following fires. We recorded 57 ant species belonging to 29 genera. Ant species composition did not significantly vary between treatments neither did ant body size. We detected significantly positive fire effects on ant richness after 1 month and 12 months, mediated by the increase in plant species richness in burned plots. Mean seed removal rates were increased in burned plots after 1 month. We showed that prescribed patch burnings in fire-prone grasslands promoted ant richness, and their foraging activity. Our study may serve as a basis for conservation decisions, showing the importance of maintenance of disturbances in grasslands.

A cross-sectional analysis on the effects of biodiversity and green space on mental well-being in Wales.

ObjectiveA growing body of evidence suggests that biodiversity and greenspaces are positively associated with mental well-being. However, studies have been undertaken over small spatial scales and population-scale evidence is lacking. This study aimed to investigate associations between parks, biodiversity and mental well-being for individuals living in Wales in 2018/2019.
 ApproachThis cross-sectional study linked GIS derived data, socio-demographic and survey datasets to analyse how mental well-being varied with biodiversity per greenspace for individuals living in Wales for each Lower Super Output Area (LSOA). Mental well-being was defined using the Warwick-Edinburgh Mental Well-being Scale (WEMWBS). All records of bird, butterfly and plant species in 2018 were downloaded from the National Biodiversity Network Atlas Wales. Greenspace measures were acquired from Ordnance Survey. Associations between greenspace, biodiversity and mental well-being were investigated using Generalised Additive Models to allow for non-linear relationships.
 ResultsThe size of the cohort was 10,441, the average age was 55 (s.d. 18.6), 55.2% were female and 94.4% were White British. This study found that greenspace area (m2), the total number of species, number of bird and number of plant species (all per m2 greenspace) had positive statistically significant relationships with mental well-being. After adjustment for socio-demographic factors, the number of plant species (per m2 greenspace) remained a significant predictor of mental well-being, with a positive linear relationship. There was no statistically significant relationship between the number of butterfly species per m2 greenspace and mental well-being in unadjusted or adjusted models. Furthermore, socio-demographic factors explained most of the variation in mental well-being.
 ConclusionThis study adds further evidence to the benefits of biodiverse environments on mental well-being through nature connectedness. Specifically, people living in an LSOA with more plant species per m2 greenspace report better mental well-being. Environmental interventions should consider increasing plant species richness which may benefit mental well-being.

Effects of crop type and production method on arable biodiversity in boreal farmland

Crop choice affects biodiversity within fields due to crop-specific characteristics and management practices. However, there is a lack of studies systematically comparing the biodiversity value of different crops across multiple taxa. This study empirically compared the diversity of plants, pollinators, predatory arthropods, and multi-taxa diversity between seven crop types and long-term environmental fallows in boreal farmland. The effects of crop production method (organic vs. conventional) on biodiversity were also examined. Biodiversity data were collected in 78 fields in Southern Finland. The studied species groups differed in their preferences for crop types and fallows, but none of them was particularly associated to spring cereal (oat), the dominant arable crop in the boreal farmland. Environmental fallows had the highest plant species richness and butterfly abundance, whereas faba bean and oilseed crop fields attracted high numbers of bumblebees. Carabid beetles were most abundant in winter cereal (rye) fields, and spiders in perennial crop types. Multi-taxa diversity was highest in fallows and lowest in spring cereal (oat), ley and cabbage fields. Organic production increased plant species richness across crop types. Hoverflies responded to the interaction of production method and crop type, being most abundant in organically managed faba bean fields. The other species groups and multi-taxa diversity were not affected by the production method. High arable land cover in the surrounding landscape had negative effect on butterflies, solitary bees and carabid beetles within fields. Our results suggest that diversifying cropping systems to include more insect-pollinated crops, winter cereals and pastures, and increasing the area of environmental fallows while maintaining landscape heterogeneity would enhance resource provision for a variety of organism groups in boreal agricultural landscapes.

A multi-site experiment to test biocontrol effects of wildflower strips in different French climate zones

Sowing of wildflower strips has been integrated in agri-environment schemes of several European countries. Their beneficial effects on natural enemies of pest insects are well documented but (1) the desired spill-over into crop fields has not always been demonstrated, and (2) the need to adapt sown mixtures to regional climatic differences has been rarely addressed.We set up a multi-site experiment in different French climatic regions to compare effects of a wildflower strip with a grass mixture and spontaneous vegetation. The design included five regions, three to five fields per region and the three strip treatments being repeated in each field. We tested strip treatment effects on vegetation (plant species richness, plant and flower cover) and on natural enemies (hoverflies, ladybirds, aphid predation). In a subset, we further analysed the spill-over into winter wheat fields including natural enemies and pest insects (cereal aphids, leaf beetles).The wildflower strip mixture developed well in all regions and increased plant species richness and flower cover compared with grass strips and spontaneous vegetation. We found a corresponding higher hoverfly abundance and aphid predation in wildflower strips that were consistent in all regions, whereas ladybird abundance was not affected. A significantly higher hoverfly abundance, aphid predation and aphid parasitism in wheat fields close to wildflower strips indicated a spill-over. No corresponding margin treatment effects were observed for aphid and leaf beetle abundance in the field. A multivariate analysis comparing the influence of climate and vegetation parameters showed that floral cover better explained variation in natural enemy abundance and predation than climate. Our results demonstrated that similar mixtures of native plants can be used over large climatic gradients to improve biocontrol. Further research is needed to improve spill-over into crop fields and to obtain consistently strong effects in different climate zones.