News


2017, October 2

LIBERATION results:
Exploring the relationships between landscape complexity, wild bee species richness and reproduction, and pollination services along a complexity gradient in the Netherlands 

Pollinator communities exhibit variable responses to changing landscape composition. A general expectation is that a decreasing cover of semi-natural habitats negatively affects pollinator reproduction, population size and pollination services, but few studies have investigated the simultaneous effects of landscape complexity on different aspects of pollinator communities and functioning.
In 20 agricultural landscape plots the size of an average Dutch farm, we studied how changing landscape
complexity affected wild bee abundance, species richness and reproduction. To measure pollination, we placed potted strawberry plants as phytometers in landscapes. Landscape complexity was characterized as the area of semi-natural habitats. In addition, we estimated floral resource abundance in each landscape plot. We expected that i) bee species richness, reproduction and pollination would be positively related to area of semi-natural habitats and flower abundance, and that ii) species richness and reproduction would be positively related to pollination.
An increase in semi-natural habitats in landscapes increased both the abundance of cavity-nesting bees colonizing trap nests, and the growth rates of experimental Bombus terrestris L. colonies, but not the species richness of wild bees measured by pan traps. There was only a tendency for higher pollination levels of strawberry plants with higher cover of semi-natural habitats. There was no relationship between species richness and bee reproduction in a landscape and the pollination services. Estimated flower abundance in landscape had a positive effect on bumblebee colony growth only and not on the other variables.
Our results suggest that, by improving habitat quality on their farms through establishing more semi-natural habitats or enhancing the flower availability in semi-natural habitats, farmers can promote reproduction of a number of functionally important bee species and the pollination services they provide. Bee species richness, however, seems to be more difficult to enhance and requires more than just creating more of the same type of habitats or flowers.


2017, August 10

LIBERATION results:
Pollination benefits are maximized at intermediate nutrient levels

Yield production in flowering crops depends on both nutrient availability and pollination, but their relative roles and potential interactions are poorly understood. We measured pollination benefits to yield in sunflower, combining a gradient in insect pollination (0, 25, 50, 100%) with a continuous gradient in nitrogen (N) fertilization (from 0 to 150 kg N ha−1) in an experiment under realistic soil field conditions. We found that pollination benefits to yield were maximized at intermediate levels of N availability, bolstering yield by approximately 25% compared with complete pollinator exclusion. Interestingly, we found little decrease in yield when insect visits were reduced by 50%, indicating that the incremental contribution of pollination by insects to yield is greater when the baseline pollination service provision is very low. Our findings provide strong evidence for interactive, nonlinear effects of pollination and resource availability on seed production. Our results support ecological intensification as a promising strategy for sustainable management of agroecosystems. In particular, we found optimal level of pollination to potentially compensate for lower N applications.



2017, August 10

LIBERATION results:
The benefits of hedgerows for pollinators and natural enemies depends on hedge quality and landscape context

Ecological intensification advocates the harnessing of regulating and supporting ecosystem services to promote more sustainable food production, and this relies on effective management of non-cropped habitats. Hedgerows are an important component of the landscape in many farming systems across the world, management of which provides a potential mechanism to enhance ecological intensification. Here we investigate the value of hedgerows in Southern England as a source of functionally important taxa, and how hedgerow quality and local landscape composition impact on their potential contribution to sustainable agriculture in arable landscapes. We show that hedgerows are a source habitat for many natural enemies which spill over into neighbouring fields, and that hedgerows provide a valuable forage resource and corridor for movement of pollinators. Hedgerow quality affects these benefits and continuous unbroken hedgerows, with a high diversity of woody species, are more valuable for the provision of bumblebees and Linyphiid spiders, while the presence of trees within the hedgerow supports Lycosid spiders. Floral resources, beyond the woody hedgerow species themselves, are also a key forage resource for hoverflies. The impact of these hedgerows on invertebrate abundance is moderated by local landscape, and hedgerows are a more valuable forage resource for pollinators in more intensely managed landscapes. Our study shows that in order to support abundant and a broad range of natural enemies and pollinators in agricultural landscapes, both hedgerows and local semi-natural habitats need to be protected and managed. The benefit of hedgerows, as a habitat for functionally important taxa depends on hedgerow quality and management practices such as avoiding gaps, high hedge species diversity and maintaining an abundant understory of plants, can improve their value for ecological intensification.

Reference: Garratt, M.P.D., Senapathi, D., Coston, D.J., Mortimer, S.R. & Potts, S.G. (2017)
The benefits of hedgerows for pollinators and natural enemies depends on hedge quality and landscape context. Agriculture, Ecosystems and Environment, 247, 363–370.


2017, July 18


LIBERATION featured on EU website (click on title to read the article):


LIBERATION results:
High cover of hedgerows in the landscape supports multiple ecosystem services in Mediterranean cereal fields

Field-margin diversification through conservation and restoration of hedgerows is becoming a prominent intervention for promoting biodiversity and associated ecosystem services in intensive agricultural landscapes. However, how increasing cover of hedgerows in the landscape can affect ecosystem services has rarely been considered.
Here, we assessed the effect of increased field-margin complexity at the local scale and increasing cover of hedgerows in the landscape on the provision of pest control, weed control and potential pollination. Locally, three types of field margin were compared as follows: (i) standard grass margin, (ii) simple hedgerow and (iii) complex hedgerow, along two independent gradients of hedgerow cover and arable land cover in the landscape. We performed an exclusion experiment to measure biological control of cereal aphids and assessed natural enemy and pest abundance in the field. We sampled plant weed communities and performed a phytometer experiment to test the effects of pollinators on plant reproductive success.
At the local scale, planting a new hedgerow or improving its structural complexity and vegetation diversity did not enhance the delivery of ecosystem services in the neighbouring field.
However, high cover of hedgerows in the landscape enhanced aphid parasitism (from 12 to 18%) and potential pollination (visitation rate and seed set increased up to 70%) irrespective of local margin quality. The cover of arable land in the landscape reduced the abundance of plant-dwelling predators and weed diversity, but did not affect the delivery of the investigated ecosystem services.
Synthesis and applications: Our results highlight the key importance of the surrounding landscape context, rather than local factors, to the delivery of ecosystem services. This suggests a need for new policies that pay particular attention to the conservation of hedgerows at large scales for promoting multiple ecosystem services in agroecosystems. Specifically, hedgerows can serve to develop a network of ecological corridors that can facilitate the movement of beneficial organisms, such as pollinators and natural enemies in the agricultural matrix. Such interventions may be a ‘low cost – high benefit solution’, since farmers can create or conserve high-quality habitats taking little or no land from crop production and without the need to change their crop management.




2017, June 06

LIBERATION results:
Arthropod Pest Control for UK Oilseed Rape 
Comparing Insecticide Efficacies, Side Effects
and Alternatives

Oilseed rape (Brassica napus) is an important combinable break crop in the UK, which is largely protected from arthropod pests by insecticidal chemicals. Despite ongoing debate regarding the use of neonicotinoids, the dominant seed treatment ingredients used for this crop, there is little publicly available data comparing the efficacy of insecticides in controlling key arthropod pests or comparing the impacts on non-target species and the wider environment. To provide an insight into these matters, a UK-wide expert survey targeting agronomists and entomologists was conducted from March to June 2015. Based on the opinions of 90 respondents, an average of 20% yield loss caused by the key arthropod pests was expected to have occurred in the absence of insecticide treatments. Relatively older chemical groups were perceived to have lower efficacy for target pests than newer ones, partly due to the development of insecticide resistance. Without neonicotinoid seed treatments, a lack of good control for cabbage stem flea beetle was perceived. Wide spectrum foliar insecticide sprays were perceived to have significantly greater negative impacts than seed treatments on users' health, natural enemies, pollinators, soil and water, and many foliar active ingredients have had potential risks for non-target arthropod species in UK oilseed rape fields for the past 25 years. Overall, 72% of respondents opposed the neonicotinoid restriction, while 10% supported it. Opposition and support of the restriction were largely based on concerns for pollinators and the wider environment, highlighting the uncertainty over the side effects of neonicotinoid use. More people from the government and research institutes leaned towards neutrality over the issue, compared to those directly involved in growing the crop. Neonicotinoid restriction was expected to result in greater effort and expenditure on pest control and lower production (0±1 t/ha less). Alternatives for future oilseed rape protection were then discussed.




2016, November 21

LIBERATION results:
Soil compaction and insect pollination modify impacts of croprotation on nitrogen fixation and yield.

Pollination and biological nitrogen fixation are key ecosystem services, but their contribution to agricultural production mightbe influenced by simplified crop rotation and soil compaction, two factors known to limit yield. In a greenhouse experiment,we investigated the combined effect of crop rotation, soil compaction, and insect pollination on yield formation and on thecontribution of biological fixation to nitrogen acquisition of faba bean. Seed yield was reduced under high soil compaction, andunder ley rotation management and it was enhanced by insect pollination. For plants grown in soil from the ley rotation, insectpollination increased individual seed weight by 50% suggesting a contribution to seed quality by pollination for crop grown insoils where nutrients are limiting yield. Crop monoculture and high soil compaction interactively reduced the contribution ofnitrogen fixation by 30%, suggesting that soil compaction exacerbates the negative effect of monoculture on nitrogen fixation.Overall the results revealed that interactive effects of management factors do affect nutrient acquisition. We provide evidencethat reduced soil quality affect the capacity of legumes to deliver key ecosystem services to the agroecosystem.




2016, October 4

LIBERATION results:
Can above-ground ecosystem services compensate 
for reduced fertilizer input and soil organic matter in 
annual crops?


1. Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop yield.
2. We exposed potted plants to all combinations of high and low levels of soil organic matter (SOM) and fertilizer supply, and placed all treatments at a variety of field sites representing a gradient in pollinator visitation rate and pest exposure. We determined the relative contribution of pollinators and pests, SOM and fertilizer supply to yield. We also tested whether SOM can moderate effects of fertilizer on yield and whether soil conditions influence the relationship between above-ground conditions and yield.
3. Increases in pollinator visitation rate and decreases in pest pressure enhanced yield more than increase in fertilizer supply. Although higher SOM content resulted in plants with more biomass and flowers, under our experimental conditions SOM neither enhanced yield, nor influenced effects of fertilizer, pollinators or pests on yield.
4. The relationships between yield, pollinator visitation rate and pest pressure did not depend on the level of fertilization, suggesting that the effects of fertilizer application and aboveground (dis)services on yield were additive. In contrast, pollinator visitation rate was more strongly related to yield at low pest pressure than at high pest pressure indicating trade-offs between above-ground services and disservices.
5. Synthesis and applications. Our results show that it is possible to increase oilseed rape yield by enhancing pollination, irrespective of supplying mineral fertilizer. Moreover, the fact that belowground
conditions did not alter the effect of above-ground conditions suggests that farmers may obtain even higher yields by maximizing both above-ground ecosystem services and external inputs. Further studies are needed to understand at which point the positive relationships between pollinator visitation and yield, as well as between fertilizer and yield, will level off. Considering above-ground and below-ground services and inputs in agro-ecosystems in conjunction is crucial in order to optimize external inputs for crop yield from an economic and ecological perspective.




2016, September 1

Soil management shapes ecosystem 
service provision and trade-offs in 
agricultural landscapes.

Agroecosystems are principally managed to maximize food provisioning 
even if they receive a large array of supporting and regulating ecosystem 
services (ESs). Hence, comprehensive studies investigating the effects of 
local management and landscape composition on the provision of and 
trade-offs between multiple ESs are urgently needed.We explored the effects 
of conservation tillage, nitrogen fertilization and landscape composition 
on six ESs (crop production, disease control, soil fertility, water quality 
regulation, weed and pest control) in winter cereals. Conservation tillage 
enhanced soil fertility and pest control, decreased water quality regulation 
and weed control, without affecting crop production and disease control. 
Fertilization only influenced crop production by increasing grain yield. 
Landscape intensification reduced the provision of disease and pest control. 
We also found tillage and landscape composition to interactively affect water
quality regulation and weed control. Under N fertilization, conventional 
tillage resulted in more trade-offs between ESs than conservation tillage. 
Our results demonstrate that soil management and landscape composition 
affect the provision of several ESs and that soil management potentially 
shapes the trade-offs between them.




2016, May 26

LIBERATION project featured in Horizon magazine:
‘Ecological intensification’ swaps pesticides for biodiversity.

While farmers often turn to pesticides and herbicides to get as much produce as possible from their land, there’s something new on the menu that could employ nature’s own resources instead.




2016, April 22

Policy Entry Points for Enabling Ecological Intensification and the EU Common Agriculture Policy (CAP)

The purpose of this document is to look at policy entry points for ecological intensification in the European Union’s Common Agricultural Policy (CAP) and other policies instruments at the national (Member States) and sub-national levels. The document explores also relevant challenges and barriers to building supporting policies for ecological intensification, and outlines a number of recommendations for those stakeholders that are its target audience – LIBERATION partner organizations, farmers and farming communities, policymakers working within the CAP and the private sector.
The key conclusions from the analysis of policy entry points at the EU, national and sub-national levels are that:
    - While the CAP was not specifically designed to target ecological intensification, a number of field and farm-level measures that could respond to stronger prioritization on environmental impacts in agricultural production may already qualify under the AEM payment schemes or are potentially applicable under cross-compliance with the Statutory Management Requirements (SMRs);
    - Above all, the challenge that most affect implementation of ecological intensification measures is the limited information available in terms of yield performance, profitability and reduced costs of inputs with respect to conventional approaches.





2016, April 12

Large‑scale pollination experiment demonstrates the importance 
of insect pollination in winter oilseed rape.

Insect pollination, despite its potential to contribute 
substantially to crop production, is not an integrated 
part of agronomic planning. A major reason for this are 
knowledge gaps in the contribution of pollinators to yield, 
which partly result from difficulties in determining areabased 
estimates of yield effects from insect pollination 
under field conditions. We have experimentally manipulated 
honey bee Apis mellifera densities at 43 oilseed rape 
Brassica napus fields over 2 years in Scandinavia. Honey 
bee hives were placed in 22 fields; an additional 21 fields 
without large apiaries in the surrounding landscape were 
selected as controls. Depending on the pollination system 
in the parental generation, the B. napus cultivars in the crop 
fields are classified as either open-pollinated or first-generation 
hybrids, with both types being open-pollinated in 
the generation of plants cultivated in the fields. Three cultivars 
of each type were grown. We measured the activity 
of flower-visiting insects during flowering and estimated 
yields by harvesting with small combine harvesters. The addition of honey bee hives to the fields dramatically increased abundance of flower-visiting honey bees in those fields. Honey bees affected yield, but the effect depended on cultivar type (p = 0.04). Post-hoc analysis revealed that open-pollinated cultivars, but not hybrid cultivars, had 11% higher yields in fields with added honey bees than those grown in the control fields (p = 0.07). To our knowledge, this is the first whole-field study in replicated landscapes to assess the benefit of insect pollination in oilseed rape. Our results demonstrate that honey bees have the potential to increase oilseed rape yields, thereby emphasizing the importance of pollinator management for optimal cultivation of oilseed rape.



2016, January 27

LIBERATION results:
The role of food retailers in improving resilience in global food supply.

We urgently need a more resilient food supply system that is robust enough to absorb and recover 
quickly from shocks, and to continuously provide food in the face of significant threats. The simplified global food supply chain we currently rely upon exacerbates threats to supply and is unstable. Much attention has been given to how producers can maximise yield, but less attention has been given to other stakeholders in the supply chain. Increasingly, transnational food retailers (supermarkets) occupy a critical point in the chain, which makes them highly sensitive to variability in supply, and able to en- courage change of practice across large areas. We contend that the concentration in the chain down to a few retailers in each country provides an opportunity to increase resilience of future supply given ap- propriate, scale-dependent interventions. We make ten recommendations aimed at reducing variability in supply that can be driven by retailers (although some of the interventions will be implemented by producers). Importantly, resilience in our food supply requires the restoration and expansion of eco
system services at the landscape-scale.



2015, November 26

LIBERATION results:
Pollinator conservation — the difference between 
managing for pollination services and preserving 
pollinator diversity.

Our review looks at pollinator conservation and highlights the 
differences in approach between managing for pollination 
services and preserving pollinator diversity. We argue that
ecosystem service management does not equal biodiversity 
conservation, and that maintaining species diversity is crucial in 
providing ecosystem resilience in the face of future
environmental change. Management and policy measures 
therefore need to focus on species not just in human dominated 
landscapes but need to benefit wider diversity of species 
including those in specialised habitats. We argue that only by 
adopting a holistic ecosystem approach we can ensure the 
conservation and sustainable use of biodiversity and
ecosystem services in the long-term.




2015, October 16

LIBERATION results:
The role of agri-environment schemes in 
conservation and environmental management.

Over half of the European landscape is under agricultural management and has been formillennia.
Many species and ecosystems of conservation concern in Europe depend on agricultural management and
are showing ongoing declines. Agri-environment schemes (AES) are designed partly to address this. They are a 
major source of nature conservation funding within the European Union (EU) and the highest conservation 
expenditure in Europe.We reviewed the structure of current AES across Europe. Since a 2003 review questioned 
the overall effectiveness of AES for biodiversity, there has been a plethora of case studies and meta-analyses 
examining their effectiveness. Most syntheses demonstrate general increases in farmland biodiversity in 
response to AES, with the size of the effect depending on the structure and management of the surrounding 
landscape. This is important in the light of successive EU enlargement and ongoing reforms of AES. We 
examined the change in effect size over time by merging the data sets of 3 recent meta-analyses and found 
that schemes implemented after revision of the EU’s agri-environmental programs in 2007 were not more 
effective than schemes implemented before revision. Furthermore, schemes aimed at areas out of production 
(such as field margins and hedgerows) are more effective at enhancing species richness than those aimed 
at productive areas (such as arable crops or grasslands). Outstanding research questions include whether 
AES enhance ecosystem services, whether they are more effective in agriculturally marginal areas than in 
intensively farmed areas, whether they are more or less cost-effective for farmland biodiversity than protected 
areas, and how much their effectiveness is influenced by farmer training and advice? The general lesson 
from the European experience is that AES can be effective for conserving wildlife on farmland, but they are
expensive and need to be carefully designed and targeted.



2015, October 16

LIBERATION results:
Trait matching of flower visitors and crops predicts fruit set better than trait diversity.

Summary
1. Understanding the relationships among trait diversity, species diversity, and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most functions, particularly for crop pollination, where interacting partners did not necessarily co-evolve.
2. Worldwide, we collected data on traits of flower visitors and crops, visitation rates to crop flowers per insect species, and fruit set in 469 fields of 33 crop systems. Through hierarchical mixed-effects models we tested whether flower-visitor trait diversity and/or trait matching between flower visitors and crops improve the prediction of crop fruit set (functioning) beyond flower-visitor species diversity and abundance.
3. Flower-visitor trait diversity was positively related to fruit set, but surprisingly did not explain more variation than flower-visitor species diversity.
4. The best prediction of fruit set was obtained by matching traits of flower visitors (body size and mouthpart length) and crops (nectar accessibility of flowers) in addition to flower-visitor abundance, species richness, and species evenness. Fruit set increased with species richness, and more so in assemblages with high evenness, indicating that additional species of flower visitors contribute more to crop pollination when species abundances are similar.
5. Synthesis and applications. Despite contrasting floral traits for crops worldwide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower-visitor species.



2015, October 8

Wildlife-friendly farming increases crop 
yield: evidence for ecological 
intensification.

Ecological intensification has been promoted as a means to achieve environmentally sustainable increases in crop yields by enhancing ecosystem functions that regulate and support production. There is, however, little direct evidence of yield benefits from ecological intensification on commercial farms growing globally important foodstuffs (grains, oilseeds and pulses). We replicated two treatments removing 3 or 8% of land at the field edge from production to create wildlife habitat in 50–60 ha patches over a 900 ha commercial arable farm in central England, and compared these to a business as usual control (no land removed). In the control fields, crop yields were reduced by as much as 38% at the field edge. Habitat
creation in these lower yielding areas led to increased yield in the cropped areas of the fields, and this positive effect became more pronounced over 6 years. As a consequence, yields at the field scale were maintained—and, indeed, enhanced for some crops—despite the loss of cropland for habitat creation. These results suggested that over a 5-year crop rotation, there would be no adverse impact on overall yield in terms of monetary value or nutritional energy. This study provides a clear demonstration that wildlife-friendly management which supports ecosystem services is compatible with, and can even increase, crop yields.



2015, September 3

LIBERATION results:
Modeling pollinating bee visitation rates in heterogeneous landscapes from foraging theory.

Pollination by bees is important for food production. Recent concerns about the declines of both domestic and wild bees, calls for measures to promote wild pollinator populations in farmland. However, to be able to efficiently promote and prioritize between measures that benefit pollinators, such as modified land use, agri-environment schemes, or specific conservation measures, it is important to have a tool that accurately predicts how bees use landscapes and respond to such measures. In this paper we compare an existing model for predicting pollination (the “Lonsdorf model”), with an extension of a general model for habitat use of central place foragers (the “CPF model”). The Lonsdorf model has been shown to perform relatively well in simple landscapes, but not in complex landscapes. We hypothesized that this was because it lacks a behavioral component, assuming instead that bees in essence diffuse out from the nest into the landscape. By adding a behavioral component, the CPF model in contrast assumes that bees only use those parts of the landscape that enhances their fitness, completely avoiding foraging in other parts of the landscape. Because foraging is directed toward the most rewarding foraging habitat patches as determined by quality and distance, foraging habitat will include a wide range of forage qualities close to the nest, but a much narrower range farther away. We generate predictions for both simple and complex hypothetical landscapes, to illustrate the effect of including the behavioral rule, and for real landscapes. In the real landscapes the models give similar predictions for visitation rates in simple landscapes, but more different predictions in heterogeneous landscapes. We also analyze the consequences of introducing hedgerows near a mass-flowering crop field under each model. The Lonsdorf model predicts that any habitat improvement will enhance pollination of the crop. In contrast, the CPF model predicts that the hedgerow must provide good nesting sites, and not just foraging opportunities, for it to benefit pollination of the crop, because good forage quality alone may drain bees away from the field. Our model can be used to optimize pollinator mitigation measures in real landscapes.



2015, July 7

LIBERATION results:
Organic farming enhances parasitoid diversity at the 
local and landscape scales.

Summary
1. The magnitude of the benefits derived from organic farming within contrasting managed landscapes remains unclear and, in particular, the potential scale-dependent response of insect parasitoids is relatively unexplored. Identifying the scale at which parasitoids are affected by organic farming will be an important step to enhance their conservation.
2. We sampled tachinid parasitoids at the centre and margin of arable and grassland fields on paired organic and conventional farms located in landscapes with different proportions of organic land. A total of 192 fields were sampled in two biogeographical regions of the UK.
3. We found that the positive effect of organic farming on tachinid parasitoid diversity can be observed at multiple spatial scales. At the local scale, we found higher abundance and species richness of tachinid parasitoids on organic than on conventional farms and on field marginsthan on field centres. At the landscape scale, the diversity of tachinids was higher in landscapes with higher proportions of organic land. At both scales, the positive effect of organic farming was clear for arable fields, while it was almost neutral for grasslands.
4. Synthesis and applications. Any attempt to enhance parasitoid diversity in agricultural landscapes needs to consider the local management in relation to the habitat type, location within the field and agricultural management in the surrounding landscape. To restore parasitoid diversity, the promotion of organic agriculture should aim to increase both the total extent of organic farming and the connectivity of individual farms. As the benefits of organic farming to biodiversity clearly spread beyond individual farm boundaries, any assessment of organic farming should consider these positive externalities.



2015, June 29

LIBERATION results:
Landscape composition affects parasitoid spillover.

The intensification of agriculture has led to a severe simplification of agricultural landscapes, resulting in
a marked reduction in the diversity of insect natural enemies. However, how this simplification shapes
the movement of insect parasitoids between crop and non-crop habitats (i.e., spillover) is still unclear. We examined the potential spillover of tachinid parasitoids from semi-natural habitats into apple orchards
across different landscapes. We sampled commercial apple orchards localized in three landscape types
(forest-, grassland- or apple-dominated landscapes) to first evaluate if landscape composition affects the
local species richness in apple orchards. Second, we tested whether the contribution of forest and
grassland habitats to the local tachinid community composition of apple orchards changes according to
landscape composition. We found that landscape composition did not affect local tachinid species
richness in apple orchards, while it affected the species spillover. Independently of the landscape, we
found highly nested communities of tachinids between apple orchards and forest habitats suggesting a
strong spillover of tachinids between these habitats. In contrast, tachinids in apple orchards were nested
with grassland habitats only in landscapes dominated by apple orchards. Our results have important
implications for the conservation of insect parasitoids in agricultural landscapes, as the spillover of
species in the crop can be affected by the type and the area of semi-natural habitats in the surrounding
landscape.



2015, June 17

LIBERATION results:
Delivery of crop pollination services is an insufficient argument for wild pollinator conservation.

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these 
ecosystem services have become a key argument for biodiversity conservation. However, it is unclear 
how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show 
that, while the contribution of wild bees to crop production is significant, service delivery is restricted to 
a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting 
wild bee communities are dominated by a small number of common species, and threatened species 
are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many 
are easily enhanced by simple conservation measures, suggesting that cost-effective management 
strategies to promote crop pollination should target a different set of species than management 
strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires 
more than just ecosystem-service-based arguments.

Reference: David Kleijn, Rachael Winfree, Ignasi Bartomeus, Luísa G Carvalheiro, Mickaël Henry, Rufus Isaacs, Alexandra-Maria Klein, Claire Kremen, Leithen K M'Gonigle, Romina Rader, Taylor H Ricketts, Neal M Williams, Nancy Lee Adamson, John S Ascher, András Báldi,  Péter Batáry, Faye Benjamin, Jacobus C Biesmeijer, Eleanor J Blitzer, Riccardo Bommarco, Mariëtte R Brand, Vincent Bretagnolle, Lindsey Button, Daniel P Cariveau, Rémy Chifflet, Jonathan F Colville, Bryan N Danforth, Elizabeth Elle, Michael P.D. Garratt, Felix Herzog, Andrea Holzschuh, Brad G Howlett, Frank Jauker, Shalene Jha, Eva Knop, Kristin M Krewenka, Violette Le Féon, Yael Mandelik, Emily A May, Mia G Park, Gideon Pisanty, Menno Reemer, Verena Riedinger, Orianne Rollin, Maj Rundlöf, Hillary S Sardiñas, Jeroen Scheper, Amber R Sciligo, Henrik G Smith, Ingolf Steffan-Dewenter, Robbin Thorp, Teja Tscharntke, Jort Verhulst, Blandina F Viana, Bernard E Vaissière, Ruan Veldtman, Catrin Westphal & Simon G Potts (2015) Delivery of crop pollination services is an insufficient argument for wild pollinator conservation. Nature Communications 6, Article number: 7414 doi:10.1038/ncomms8414

Direct access:


2015, April 16

LIBERATION results:
Crop management modifies the benefits of insect pollination in oilseed rape.

In a factorial field plot experiment, high and low levels of inorganic nitrogen and of insect pollinators
visiting the crop were manipulated and their combined effects on oilseed rape yield were quantified. A
third factor was also included, testing whether different cultivars responded differently to the tested
factors. Insect pollination was required to reach high yield and seed quality (oil content). Final benefits of
pollination service were, however, greatly modified by cultivar, where the seed yield of the openpollinated cultivar largely depended on insect pollination whereas the two hybrid cultivars did not. A
near significant interaction between nitrogen input and insect pollination was also found, i.e. benefits to
crop yield from insect pollination seemed to increase with decreased nitrogen levels. The differential
response of the three cultivars suggested opportunities to use cultivars that are less dependent on insect
pollination in landscapes where this service has been deteriorated. Increased access of nitrogen seems to
partly compensate yield losses from poor insect pollination. Integrating conservation, environmental and
agronomic sciences is therefore crucial to sustain agriculture productions through optimized management of agronomic inputs and biodiversity-based ecosystem services.



2015, January 12

LIBERATION results:
Testing scale-dependent effects of semi-natural habitats on farmland biodiversity.

The effectiveness of conservation interventions for maximizing biodiversity benefits from agri-environment schemes (AESs) is expected to depend on the quantity of semi-natural habitats in the surrounding landscape. To verify this hypothesis, we developed a hierarchical sampling design to assess the effects of field boundary type and cover of semi-natural habitats in the landscape at two nested spatial scales. We sampled three types of field boundaries with increasing structural complexity (grass margin - simple hedgerow - complex hedgerow) in paired landscapes with presence or absence of semi-natural habitats (radius 0.5 km), that in turn, were nested within 15 areas with different proportions of semi-natural habitats at a larger spatial scale (10 × 10 km). Overall, 90 field boundaries were sampled across a Mediterranean region (NE Italy). We considered species richness response across three different taxonomic groups: vascular plants, butterflies, and tachinid flies. No interactions between type of field boundary and surrounding landscape were found at either 0.5 and 10 km indicating that the quality of field boundary had the same effect irrespective of the cover of semi-natural habitats. At the local scale, extended-width grass margins yielded higher plant species richness, while hedgerows yielded higher species richness of butterflies and tachinids. At the 0.5 km landscape scale, the effect of the proportion of semi-natural habitats was neutral for plants and tachinids, while butterflies were positively related to the proportion of forest. At the 10 km landscape scale, only butterflies responded positively to the proportion of semi-natural habitats. Our study confirmed the importance of testing multiple scales when considering species from different taxa and with different mobility. We showed that the quality of field boundaries at the local scale was an important factor in enhancing farmland biodiversity. For butterflies, AESs should focus particular attention on preservation of forest patches in agricultural landscapes within 0.5 km as well as the conservation of semi-natural habitats at a wider landscape scale.



2014, December 11

Diversification practices reduce organic 
to conventional yield gap.

Agriculture today places great strains on biodiversity, soils, water and the 
atmosphere, and these strains will be exacerbated if current trends in population 
growth, meat and energy consumption, and food waste continue. 
Thus, farming systems that are both highly productive and minimize environmental 
harms are critically needed. How organic agriculture may contribute to 
world food production has been subject to vigorous debate over the past 
decade. Here, we revisit this topic comparing organic and conventional 
yields with a new meta-dataset three times larger than previously used (115 
studies containing more than 1000 observations) and a new hierarchical 
analytical framework that can better account for the heterogeneity and structure 
in the data. We find organic yields are only 19.2% (+3.7%) lower than 
conventional yields, a smaller yield gap than previous estimates. More importantly, 
we find entirely different effects of crop types and management 
practices on the yield gap compared with previous studies. For example, we 
found no significant differences in yields for leguminous versus non-leguminous 
crops, perennials versus annuals or developed versus developing 
countries. Instead, we found the novel result that two agricultural diversification 
practices, multi-cropping and crop rotations, substantially reduce the 
yield gap (to 9+4% and 8+5%, respectively) when the methods were 
applied in only organic systems. These promising results, based on robust 
analysis of a larger meta-dataset, suggest that appropriate investment in agroecological 
research to improve organic management systems could greatly 
reduce or eliminate the yield gap for some crops or regions.



2014, November 28
 
Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands.
 
Growing concern about bee declines and associated loss of pollination services has increased the urgency to identify the underlying causes. So far, the identification of the key drivers of decline of bee populations has largely been based on speculation. We assessed the relative importance of a range of proposed factors responsible for wild bee decline and show that loss of preferred host plant species is one of the main factors associated with the decline of bee populations in The Netherlands. Interestingly, species foraging on crop plant families have stable or increasing populations. These results indicate that mitigation strategies for loss of wild bees will only be effective if they target the specific host plants of declining bee species.
 
 

2014, June 5
 
EU agricultural reform fails on biodiversity.
 
In December 2013, the European Union (EU) enacted the reformed Common Agricultural Policy (CAP) for 2014–2020, allocating almost 40% of the EU's budget and influencing management of half of its terrestrial area. Many EU politicians are announcing the new CAP as “greener,” but the new environmental prescriptions are so diluted that they are unlikely to benefit biodiversity. Individual Member States (MSs), however, can still use flexibility granted by the new CAP to design national plans to protect farmland habitats and species and to ensure long-term provision of ecosystem services.
 
 

2014, April 4

Glossary of terms on ecosystem services in agriculture published by FAO.

If you have any questions about terminology used in the debate on ecological intensification you can look it up here:


 2014, April 3
 
LIBERATION Community of Practice on Ecological Intensification launched.
 
As part of the Liberation project the FAO, with its partner the Platform for Agrobiodiversity Research (PAR) have recently launched the Community of Practice on Ecological Intensification. The information-sharing platform aims to animate a community of practice amongst specialists in fields relevant to ecological intensification. You are warmly invited to visit the website: http://agrobiodiversityplatform.org/liberation/
 

2014, January 6

Pollination is known to improve yields of many crops, but comprehensive benefits, including crop quality and market value, remain unknown. Klatt et al. (2014) set up a field experiment with nine strawberry varieties and assessed the influence of self, wind en bee pollination on strawberry fruits, using exclusion treatments. The showed bee pollination to improve fruit quantity as well as quality (shape, colour, firmness, sugar-acid ratio) and thereby market value. Bee pollination resulted in longer shelf life, reducing fruit loss by at least 11%. These results demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.

Reference: Klatt BK, Holzschuh A, Westphal C, Clough Y, Smit I, Pawelzik E, Tscharntke T. (2014). Bee pollination improves crop quality, shelf life and commercial value. Proc. R. Soc. B. 281: 20132440.


2013, September 19

As part of the reform of the common agricultural policy the European Commission proposed to make more diverse crop rotations conditional for receiving agricultural subsidies. Subsequent negotiations significantly watered down these proposals but a recent meta-analyses suggests that the original proposal would have been a step in the right direction from the perspective of farming efficiency as well as biodiversity. “Adding one or more crops in rotation to a monoculture increased total soil carbon by 3.6% and total nitrogen by 5.3%. When rotations included a cover crop (i.e. crops that are not harvested but produced to enrich the soil and capture inorganic nitrogen), total carbon increased by 8.5% and total nitrogen 12.8%.” The authors conclude that “Crop rotations, especially those that include cover crops, sustain soil quality and productivity by enhancing soil C, N and microbial biomass, making them a cornerstone for sustainable agroecosystems.”

Reference: McDaniel,M.D.  Tiemann, L.K. & Grandy A.S. (2014). In press. Does agriculturalcrop diversity enhance soil microbial biomass and organic matter dynamics? A meta-analysis. Ecological Applications. http://dx.doi.org/10.1890/13-0616.1


2013, September 10

“Biodiversity counteracts potential adverse effects of climate change on pollination service delivery. Climate change might negatively affect agricultural production by causing a mismatch between the flowering time of insect-pollinated crops and the flight period of pollinating insects. A recent study on apple found that high levels of biodiversity buffer the negative effects of species-specific phenological shifts and maintain pollination synchrony at the community level in this crop. This was caused by complementarity among bee species’ activity periods.”

Reference: Bartomeus, I., Park, M.G., Gibbs, J., Danforth, B.N., Lakso, A.N. & Winfree, R. (2014). Biodiversity ensures plant–pollinator phenological synchrony against climate change. Ecology Letters, doi: 10.1111/ele.12170.


2013, July 11

Long-term Postdoc vacancy in Ecology


2013, July 4

“Despite the widespread concern about the fate of pollinators and the ecosystem services they deliver, we still have surprisingly scarce scientific data on the magnitude of pollinator declines and its actual contribution to crop pollination and food security. Using recently published data Bartomeus and Winfree show that bee species that are currently delivering most of the ecosystem services (i.e. crop pollination) are not among the species showing declining trends, but rather appear to thrive in human-dominated landscapes.”

Reference: Bartomeus I, Winfree R. (2013). Pollinator declines: reconciling scales and implications for ecosystem services. F1000Research 2013, 2:146


2013, June 6 

“How can we  meet the rising demands for agricultural products but avoid large-scale environmental degradation of the countryside? A new paper presenting the framework of ecological intensification highlights potential strategies avenues and points avenues worth exploring. The basic principle is to mobilize ecosystem services such as nutrient cycling, pollination and pest control to augment and/or substitute conventional practices. The paper furthermore identifies knowledge gaps that prevent rapid adoption of this approach by  the farming community. Many of these knowledge gaps will be addressed in the LIBERATION project.”

Reference: Bommarco, R., Kleijn, D. & Potts, S.G. (2013). Ecologicalintensification: harnessing ecosystem services for food security. Trends in Ecology & Evolution, 28, 230-238.