Effectiveness of agri-environmental management on pollinators is moderated more by ecological contrast than by landscape structure or land-use intensity
Marja, Riho ; Kleijn, David ; Tscharntke, Teja ; Klein, Alexandra Maria ; Frank, Thomas ; Batáry, Péter - \ 2019
Ecology Letters 22 (2019)9. - ISSN 1461-023X - p. 1493 - 1500.
Agri-environmental schemes - bees - biodiversity - butterflies - ecosystem services - flower strips - hoverflies - land-use intensity - meta-analysis
Agri-environment management (AEM) started in the 1980s in Europe to mitigate biodiversity decline, but the effectiveness of AEM has been questioned. We hypothesize that this is caused by a lack of a large enough ecological contrast between AEM and non-treated control sites. The effectiveness of AEM may be moderated by landscape structure and land-use intensity. Here, we examined the influence of local ecological contrast, landscape structure and regional land-use intensity on AEM effectiveness in a meta-analysis of 62 European pollinator studies. We found that ecological contrast was most important in determining the effectiveness of AEM, but landscape structure and regional land-use intensity played also a role. In conclusion, the most successful way to enhance AEM effectiveness for pollinators is to implement measures that result in a large ecological improvement at a local scale, which exhibit a strong contrast to conventional practices in simple landscapes of intensive land-use regions.
Evolution of plant growth and defense in a continental introduction
Agrawal, A.A. ; Hastings, A.P. ; Bradburd, G.S. ; Woods, E.C. ; Züst, T. ; Harvey, J.A. ; Bukovinszki, T. - \ 2015
adaptation - coevolution - ecology - chemical - trade offs - butterflies - plant
Substantial research has addressed adaptation of nonnative biota to novel environments, yet surprisingly little work has integrated population genetic structure and the mechanisms underlying phenotypic differentiation in ecologically important traits. We report on studies of the common milkweed Asclepias syriaca, which was introduced from North America to Europe over the past 400 years and which lacks most of its specialized herbivores in the introduced range. Using 10 populations from each continent grown in a common environment, we identified several growth and defense traits that have diverged, despite low neutral genetic differentiation between continents. We next developed a Bayesian modeling approach to account for relationships between molecular and phenotypic differences, confirming that continental trait differentiation was greater than expected from neutral genetic differentiation. We found evidence that growth-related traits adaptively diverged within and between continents. Inducible defenses triggered by monarch butterfly herbivory were substantially reduced in European populations, and this reduction in inducibility was concordant with altered phytohormonal dynamics, reduced plant growth, and a trade-off with constitutive investment. Freedom from the community of native and specialized herbivores may have favored constitutive over induced defense. Our replicated analysis of plant growth and defense, including phenotypically plastic traits, suggests adaptive evolution following a continental introduction.
Transboundary ecological networks as an adaptation strategy to climate change: The example of the Dutch - German border
Rüter, S. ; Vos, C.C. ; Eupen, M. van; Rühmkorf, H. - \ 2014
Basic and Applied Ecology 15 (2014)8. - ISSN 1439-1791 - p. 639 - 650.
maculinea-teleius - conservation - range - butterflies - impacts - biodiversity - landscapes - models - scale - recommendations
Establishing ecological networks across national boundaries is essential for species to adapt to shifts in future suitable climate zones. This paper presents a method to assess whether the existing ecological network in the Dutch – German border region is “climate proof”. Using distribution data and climate envelope models for 846 species in Europe (mammals, birds, reptiles, amphibians and butterflies) we identified 216 species with climate-induced range shifts in the border region. A range expansion is predicted for 99 species and the ranges of 117 species are predicted to contract. The spatial cohesion of the ecological network was analysed for selected species that vary in habitat requirements and colonisation ability (forest species: Brenthis daphne, Dendrocopos medius; wetland species: Maculinea teleius, Lutra lutra). The assessment shows that optimising transboundary networks and developing corridors seems a suitable adaptation strategy for the forest species and for L. lutra. For the immobile butterfly M. teleius, the present habitat network is too weak and translocation into future suitable climate space seems to be a more appropriate adaptation measure. Our results underline that due to climate change landscape planning and management should not only focus on areas where target species occur today. The presented method can identify strongholds and bottlenecks in transboundary ecological networks and incorporate demands of climate adaptation into spatial planning which forms the basis for taking measures at a more detailed level.
Synergistic effects of direct and indirect defences on herbivore egg survival in a wild crucifer
Fatouros, N.E. ; Pineda, A. ; Huigens, M.E. ; Broekgaarden, C. ; Shimwela, M.M. ; Figueroa Candia, I.A. ; Verbaarschot, P. ; Bukovinszky, T. - \ 2014
Proceedings of the Royal Society. B: Biological Sciences 281 (2014)1789. - ISSN 0962-8452 - 9 p.
furcifera horvath homoptera - plant defense - trade-offs - antiherbivore defenses - natural enemies - fitness costs - brassica-rapa - resistance - oviposition - butterflies
Evolutionary theory of plant defences against herbivores predicts a trade-off between direct (anti-herbivore traits) and indirect defences (attraction of carnivores) when carnivore fitness is reduced. Such a trade-off is expected in plant species that kill herbivore eggs by exhibiting a hypersensitive response (HR)-like necrosis, which should then negatively affect carnivores. We used the black mustard (Brassica nigra) to investigate how this potentially lethal direct trait affects preferences and/or performances of specialist cabbage white butterflies (Pieris spp.), and their natural enemies, tiny egg parasitoid wasps (Trichogramma spp.). Both within and between black mustard populations, we observed variation in the expression of Pieris egg-induced HR. Butterfly eggs on plants with HR-like necrosis suffered lower hatching rates and higher parasitism than eggs that did not induce the trait. In addition, Trichogramma wasps were attracted to volatiles of egg-induced plants that also expressed HR, and this attraction depended on the Trichogramma strain used. Consequently, HR did not have a negative effect on egg parasitoid survival. We conclude that even within a system where plants deploy lethal direct defences, such defences may still act with indirect defences in a synergistic manner to reduce herbivore pressure.
A tritrophic approach to the preference-performance hypothesis involving an exotic and a native plant
Fortuna, T.F.M. ; Woelke, J.B. ; Hordijk, C.A. ; Jansen, J.J. ; Dam, N.M. van; Vet, L.E.M. ; Harvey, J.A. - \ 2013
Biological Invasions 15 (2013)11. - ISSN 1387-3547 - p. 2387 - 2401.
parasitoids cotesia-glomerata - phytophagous insects - oviposition preference - invasive plant - c-rubecula - specialist herbivore - bunias orientalis - natural enemies - host - butterflies
Exotic plants often generate physical and chemical changes in native plant communities where they become established. A major challenge is to understand how novel plants may affect trophic interactions in their new habitats, and how native herbivores and their natural enemies might respond to them. We compared the oviposition preference and offspring performance of the crucifer specialist, Pieris brassicae, on an exotic plant, Bunias orientalis, and on a related native plant, Sinapis arvensis. Additionally, we studied the response of the parasitoid, Cotesia glomerata to herbivore-induced plant volatiles (HIPV) and determined the volatile blend composition to elucidate which compound(s) might be involved in parasitoid attraction. On both host plants we also compared the parasitism rate of P. brassicae by C. glomerata. Female butterflies preferred to oviposit on the native plant and their offspring survival and performance was higher on the native plant compared to the exotic. Although, headspace analysis revealed qualitative and quantitative differences in the volatile blends of both plant species, C. glomerata did not discriminate between the HIPV blends in flight-tent bioassays. Nevertheless, parasitism rate of P. brassicae larvae was higher on the native plant under semi-field conditions. Overall, P. brassicae oviposition preference may be more influenced by bottom-up effects of the host plant on larval performance than by top-down pressure exerted by its parasitoid. The potential for dietary breadth expansion of P. brassicae to include the exotic B. orientalis and the role of top-down processes played by parasitoids in shaping herbivore host shifts are further discussed
Mitochondrial DNA signature for range-wide populations of Bicyclus anynana suggests a rapid expansion from recent refugia
Jong, M.A. de; Wahlberg, N. ; Eijk, M. van; Brakefield, P.M. ; Zwaan, B.J. - \ 2011
PLoS ONE 6 (2011)6. - ISSN 1932-6203 - 5 p.
lepidoptera - butterflies - plasticity - biology - systematics - haplotypes - neutrality - evolution - selection - markers
This study investigates the genetic diversity, population structure and demographic history of the afrotropical butterfly Bicyclus anynana using mitochondrial DNA (mtDNA). Samples from six wild populations covering most of the species range from Uganda to South Africa were compared for the cytochrome c oxidase subunit gene (COI). Molecular diversity indices show overall high mtDNA diversity for the populations, but low nucleotide divergence between haplotypes. Our results indicate relatively little geographic population structure among the southern populations, especially given the extensive distributional range and an expectation of limited gene flow between populations. We implemented neutrality tests to assess signatures of recent historical demographic events. Tajima's D test and Fu's FS test both suggested recent population growth for the populations. The results were only significant for the southernmost populations when applying Tajima's D, but Fu's FS indicated significant deviations from neutrality for all populations except the one closest to the equator. Based on our own findings and those from pollen and vegetation studies, we hypothesize that the species range of B. anynana was reduced to equatorial refugia during the last glacial period, and that the species expanded southwards during the past 10.000 years. These results provide crucial background information for studies of phenotypic and molecular adaptation in wild populations of B. anynana
Optimizing grassland management for flower-visiting insects in roadside verges
Noordijk, J. ; Schaffers, A.P. ; Delille, K. ; Sykora, K.V. - \ 2009
Biological Conservation 142 (2009)10. - ISSN 0006-3207 - p. 2097 - 2103.
calcareous grasslands - conservation management - pollinator diversity - species-diversity - plant-communities - butterflies - vegetation - responses - biodiversity - landscapes
The decline of flower-visiting insects is a threat to ecological processes and to the services these insects provide. Roadside verges in the Netherlands span approximately 80,000 km and are often covered with semi-natural grasslands. As such, they also provide a suitable habitat for many insects, but this has received little attention so far. We investigated the effects of different management treatments on flower-visiting insects. We studied flower visitation in a 3 years old experimental set-up with five mowing treatments each replicated five times. Management types were: no management and mowing once or twice per year with and without the removal of hay, representing common forms of management and neglect. During an entire growing season, both flowers (number of species and inflorescences) as well as insects (total abundance and actual flower visits) were investigated. Mowing twice per year with removal of hay showed highest values for all measured variables and this effect persisted throughout the growing season. The early summer cut proved to be very important for insect feeding opportunities, due to the re-flowering of plants later in the growing season. Flower abundance showed high correlations with both plant species richness and the number of insect visits. Although overall, mowing twice a year with hay removal was the most beneficial treatment for flower-visiting insects, these plots were entirely devoid of flowers for some period right after mowing, indicating that a rotational scheme might further promote insect diversity and abundance
A new hidden species of the Cymothoe caenis-complex (Lepidoptera: Nymphalidae) from western Africa
Velzen, R. van; Larsen, T.B. ; Bakker, F.T. - \ 2009
Zootaxa 2197 (2009). - ISSN 1175-5326 - p. 53 - 63.
dna barcodes - rain-forest - butterflies
Butterflies of the Afrotropical genus Cymothoe are characterised by sexual dimorphism. Females of the most common species of the genus, Cymothoe caenis Drury, occur in many different forms in the equatorial zone, while only a single form is present west of the Niger Delta in Nigeria, raising the question as to whether the two populations need taxonomic recognition. We present molecular and genitalic evidence that the western populations of C. caenis s.l. comprise a distinct species: Cymothoe druryi sp. nov.
Adapting landscapes to climate change: examples of climate-proof ecosystem networks and priority adaptation zones
Vos, C.C. ; Berry, P. ; Opdam, P. ; Baveco, H. ; Nijhof, B.S.J. ; O'Hanley, J. ; Bell, C. ; Kuipers, H. - \ 2008
Journal of Applied Ecology 45 (2008)6. - ISSN 0021-8901 - p. 1722 - 1731.
klimaatverandering - soortendiversiteit - habitatverbindingszones - natura 2000 - dispersie - modellen - climatic change - species diversity - habitat corridors - natura 2000 - dispersion - models - change impacts - habitat fragmentation - species distributions - land-use - biodiversity - conservation - dispersal - butterflies - decline - policy
1. Climate change has been inducing range shifts for many species as they follow their suitable climate space and further shifts are projected. Whether species will be able to colonize regions where climate conditions become suitable, so-called 'new climate space', depends on species traits and habitat fragmentation. 2. By combining bioclimate envelope models with dispersal models, we identified areas where the spatial cohesion of the ecosystem pattern is expected to be insufficient to allow colonization of new climate space. 3. For each of three ecosystem types, three species were selected that showed a shift in suitable climate space and differed in habitat fragmentation sensitivity. 4. For the 2020 and 2050 time slices, the amount of climatically suitable habitat in northwest Europe diminished for all studied species. Additionally, significant portions of new suitable habitat could not be colonized because of isolation. Together, this will result in a decline in the amount of suitable habitat protected in Natura 2000 sites. 5. We develop several adaptation strategies to combat this problem: (i) link isolated habitat that is within a new suitable climate zone to the nearest climate-proof network; (ii) increase colonizing capacity in the overlap zone, the part of a network that remains suitable in successive time frames; (iii) optimize sustainable networks in climate refugia, the part of a species' range where the climate remains stable. 6. Synthesis and applications. Following the method described in this study, we can identify those sites across Europe where ecosystem patterns are not cohesive enough to accommodate species' responses to climate change. The best locations for climate corridors where improving connectivity is most urgent and potential gain is highest can then be pinpointed.
Interacting effects of landscape context and habitat quality on flower visiting insects in agricultural landscapes
Kleijn, D. ; Langevelde, F. van - \ 2006
Basic and Applied Ecology 7 (2006)3. - ISSN 1439-1791 - p. 201 - 214.
agri-environment schemes - field boundaries - bumble-bees - fragmented landscape - species richness - biodiversity - butterflies - scale - conservation - communities
Landscape context and habitat quality may have pronounced effects on the diversity of flower visiting insects. We investigated whether the effects of landscape context and habitat quality on flower visiting insects interact in agricultural landscapes in the Netherlands. Landscape context was expressed as the area of semi-natural habitats or the density of linear landscape features, and was quantified at spatial scales ranging from 250 to 2000 m. Habitat quality was determined as flower abundance. Species richness and abundance of hoverflies and bees were determined along 16 stream banks experiencing similar environmental conditions but situated in areas with contrasting landscape context. Only flower abundance and the area of semi-natural habitats within 500¿1000 m were significantly related to species richness of hoverflies and bees and these factors had interacting effects on both species groups. Our results suggest that the regional area of semi-natural habitats had a positive effect on hoverfly species richness when flower abundance was relatively high, but not when flower abundance was low. Moreover, flower abundance had positive effects on hoverfly species richness only in areas with relatively many semi-natural habitats. Contrastingly, flower abundance had a more positive effect on bee species richness in landscapes with few semi-natural habitats compared to landscapes with more semi-natural habitats. Our results suggest that the importance of landscape context for the species richness of flower visiting insects depends upon the quality of the habitat patches
Developing indicators for European birds
Gregory, R.D. ; Strien, A. van; Vorisek, P. ; Meyling, A.W.G. ; Noble, D.G. ; Foppen, R.P.B. ; Gibbons, D.W. - \ 2005
Philosophical Transactions of the Royal Society B. Biological sciences 360 (2005)1454. - ISSN 0962-8436 - p. 269 - 288.
amphibian population declines - lowland farmland birds - agricultural intensification - survival rates - trends - biodiversity - britain - abundance - butterflies - extinction
The global pledge to deliver `a significant reduction in the current rate of biodiversity loss by 2010¿ is echoed in a number of regional and national level targets. There is broad consensus, however, that in the absence of conservation action, biodiversity will continue to be lost at a rate unprecedented in the recent era. Remarkably, we lack a basic system to measure progress towards these targets and, in particular, we lack standard measures of biodiversity and procedures to construct and assess summary statistics. Here, we develop a simple classification of biodiversity indicators to assist their development and clarify purpose. We use European birds, as example taxa, to show how robust indicators can be constructed and how they can be interpreted. We have developed statistical methods to calculate supranational, multi-species indices using population data from national annual breeding bird surveys in Europe. Skilled volunteers using standardized field methods undertake data collection where methods and survey designs differ slightly across countries. Survey plots tend to be widely distributed at a national level, covering many bird species and habitats with reasonable representation. National species' indices are calculated using log-linear regression, which allows for plot turnover. Supranational species' indices are constructed by combining the national species' indices weighted by national population sizes of each species. Supranational, multi-species indicators are calculated by averaging the resulting indices. We show that common farmland birds in Europe have declined steeply over the last two decades, whereas woodland birds have not. Evidence elsewhere shows that the main driver of farmland bird declines is increased agricultural intensification. We argue that the farmland bird indicator is a useful surrogate for trends in other elements of biodiversity in this habitat
Gap crossing decisions by reed warblers (Acrocephalus scirpaceus) in agricultural landscapes
Bosschieter, L. ; Goedhart, P.W. - \ 2005
Landscape Ecology 20 (2005)4. - ISSN 0921-2973 - p. 455 - 468.
breeding dispersal - habitat corridors - small mammals - forest birds - movements - connectivity - arundinaceus - butterflies - patterns - patches
To meet the need for research on the requirements for corridors for marshland birds, this study set out to quantify gap crossing decisions made by reed warblers moving through the landscape. In three experiments, reed warblers were released into landscape situations with different gap sizes and their movement towards reed patches fringing a watercourse were monitored. In all experiments, most birds flew over the smallest gap towards the nearest reed patch. In the experiment with two gap sizes, the probability of crossing a gap was a function of the ratio between distances to the reed patches. In the experiment with increasing gap sizes, most birds crossed the smaller gaps frequently. Near the bigger gaps, birds did not cross the gaps; instead, they only crossed the watercourse repeatedly. In the third experiment with more realistic landscape configurations.. the birds preferred nearby non-reed landscape elements to more distant reed patches. It is concluded that reed warblers were reluctant to cross gaps wider than 50 m. The results suggest that the presence and size of gaps in reed patches affect reed warblers' local gap-crossing decisions: when given a choice, the birds prefer to cross the smallest gap. Furthermore, reed warblers may be directed towards suitable marshlands by creating corridors of reed vegetation with gaps no wider than 50 m. The surrounding agricultural landscape and the presence of trees and ditches could decrease the reluctance to cross gaps in corridors.