Ecological intensification: bridging the gap between science and practice

There is worldwide concern about the environmental costs of conventional intensification of agriculture. Growing evidence suggests that ecological intensification of mainstream farming can safeguard food production, with accompanying environmental benefits; however, the approach is rarely adopted by farmers. Our review of the evidence for replacing external inputs with ecosystem services shows that scientists tend to focus on processes (e.g., pollination) rather than outcomes (e.g., profits), and express benefits at spatio-temporal scales that are not always relevant to farmers. This results in mismatches in perceived benefits of ecological intensification between scientists and farmers, which hinders its uptake. We provide recommendations for overcoming these mismatches and highlight important additional factors driving uptake of nature-based management practices, such as social acceptability of farming

Shrubs and Degraded Permafrost Pave the Way for Tree Establishment in Subarctic Peatlands

Arctic and subarctic ecosystems are changing rapidly in species composition and functioning as they warm twice as fast as the global average. It has been suggested that tree-less boreal landscapes may shift abruptly to tree-dominated states as climate warms. Yet, we insufficiently understand the conditions and mechanisms underlying tree establishment in the subarctic and arctic regions to anticipate how climate change may further affect ecosystem structure and functioning. We conducted a field experiment to assess the role of permafrost presence, micro-topography and shrub canopy on tree establishment in almost tree-less subarctic peatlands of northern Finland. We introduced seeds and seedlings of four tree-line species and monitored seedling survival and environmental conditions for six growing seasons. Our results show that once seedlings have emerged, the absence of permafrost can enhance early tree seedling survival, but shrub cover is the most important driver of subsequent tree seedling survival in subarctic peatlands. Tree seedling survival was twice as high under an intact shrub canopy than in open conditions after shrub canopy removal. Under unclipped control conditions, seedling survival was positively associated with dense shrub canopies for half of the tree species studied. These strong positive interactions between shrubs and trees may facilitate the transition from today's treeless subarctic landscapes towards tree-dominated states. Our results suggest that climate warming may accelerate this vegetation shift as permafrost is lost, and shrubs further expand across the subarctic.Peer reviewe

Pathways towards a sustainable future envisioned by early-career conservation researchers

Scientists have warned decision-makers about the severe consequences of the global environmental crisis since the 1970s. Yet ecological degradation continues and little has been done to address climate change. We investigated early-career conservation researchers' (ECR) perspectives on, and prioritization of, actions furthering sustainability. We conducted a survey (n = 67) and an interactive workshop (n = 35) for ECR attendees of the 5th European Congress of Conservation Biology (2018). Building on these data and discussions, we identified ongoing and forthcoming advances in conservation science. These include increased transdisciplinarity, science communication, advocacy in conservation, and adoption of a transformation-oriented social–ecological systems approach to research. The respondents and participants had diverse perspectives on how to achieve sustainability. Reformist actions were emphasized as paving the way for more radical changes in the economic system and societal values linked to the environment and inequality. Our findings suggest that achieving sustainability requires a strategy that (1) incorporates the multiplicity of people's views, (2) places a greater value on nature, and (3) encourages systemic transformation across political, social, educational, and economic realms on multiple levels. We introduce a framework for ECRs to inspire their research and practice within conservation science to achieve real change in protecting biological diversity.</p

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved

Data for: Insect pollination is the weakest link in the production of a hybrid seed crop

Data on stem circumference, nectar production, pollinator visitation rates and marketable seed yield of three genetic lines of leek hybrid seed production under conventional and reduced treatments of fertilisation, irrigation and pollination

Towards ecological intensification : the relative importance of wild pollinators as an agricultural input in seed production

The importance of wild pollinators compared to conventional agricultural management is undervalued, suggests the PhD thesis of Thijs Fijen of Wageningen University. A study in commercial leek seed production fields shows that wild pollinators contribute as much to crop yield as plant quality. Honeybees, placed next to flowering leek fields specifically for pollination, do not contribute much to crop yield. Experimental work confirmed these findings: a 50% reduction in pollination leads to much larger reductions in seed yield than similar reductions in fertilizer applications or irrigation. Surprisingly, a 50% reduction in fertilisation resulted in equally high, or higher crop yields. These results may explain the international trend that crop yields of insect-pollinated crops increase less fast as those of wind-pollinated crops. The research of Fijen furthermore shows that both crop pollination and pollinator biodiversity in agricultural landscapes can be promoted by better protection of semi-natural habitats such as flower-rich road sides and nature areas.</p

Mass-migrating bumblebees : An overlooked phenomenon with potential far-reaching implications for bumblebee conservation

Bumblebees are one of the most commonly studied pollinators, but they are declining in large parts of their distribution. Whether bumblebees can cope with anthropogenic disturbances such as climate change and habitat loss depends largely on their dispersal capacity. While bumblebee queen dispersal is estimated to be only a few kilometres, bird migration sites have documented mass-migration events with peak migration of 70 bumblebee queens per minute, indicating that bumblebees can migrate over larger distances than previously thought. The open-access database trektellen.org contains 10 daily counts of >1,000 migrating queens past single points in the Netherlands, and one in the United Kingdom (total bumblebee records 65,430; range 1–11,142 individuals), mostly in early spring. Such mass-migration events are poorly documented in the scientific literature, and usually when describing migrations of other insects such as syrphids and social wasps. Most common European bumblebee species were documented to migrate. Bumblebees were observed flying at sea, coming from sea and flying towards the sea, showing that they can cross large water bodies. The wind direction might have helped to concentrate migration at landscape bottlenecks. On 1 day, bumblebee mass-migration was documented on two sites located 200 km apart. Together with the concentrated and directional flight this suggests that they can migrate for several hundreds of kilometres. Because most mass-migration events occur in spring, large-scale shortage in suitable nesting sites may be the trigger for mass-migration (e.g. due to high queen survival or low vole numbers). Future studies should test whether this is the case, or whether bumblebees show annual seasonal migration. Synthesis and applications. Much remains unclear about bumblebee migration, but it may have large consequences for the conservation of bumblebees and the ecosystem services they provide. For example, bumblebees in highly disturbed areas like agricultural landscapes may be continuously supplemented by queens from far-away productive natural areas. This suggests that large-scale conservation initiatives are required to maintain viable populations of common and endangered species. Structured observations and modern-day technology, like isotope analyses or radar monitoring, may shed light on the drivers and consequences of the overlooked phenomenon of bumblebee migration.</p

How to efficiently obtain accurate estimates of flower visitation rates by pollinators

Regional declines in insect pollinators have raised concerns about crop pollination. Many pollinator studies use visitation rate (pollinators/time) as a proxy for the quality of crop pollination. Visitation rate estimates are based on observation durations that vary significantly between studies. How observation duration relates to the accuracy of the visitation rate estimate is, however, unknown. We studied this relationship using six day-long observations (06:00. h-19:00. h) in leek-seed production fields (totalling 78. h). We analysed beyond which point in time observing longer did not significantly improve the accuracy of the visitation rate estimate (minimum observation duration). We furthermore explored the relationship between the minimum observation duration and visitation rate, time of day and temperature. We found that the minimum observation duration (mean. ±. SD: 24. ±. 11.9. min) was significantly related to visitation rate, where the observation time required to obtain accurate estimates decreased with increasing visitation rate. Minimum observation duration varied greatly between days and between fields but not within days. Within days, the visitation rates differed significantly only between the hour-intervals 06:00. h-07:00. h (lowest visitation rate) and 09:00. h-11:00. h (highest rate). Minimum observation duration decreased up to around 22. °C beyond which it remained fairly stable. Surprisingly, even after three day-long observations on the same plant we found new pollinator species visiting the flowers, suggesting that species-richness estimates based on plant observations alone probably underestimate true species richness. Because especially between-day variation in visitation rate on single plants can be large, reliable estimates of the pollinator visitation rate during the plant's flowering time require observations on multiple days. Standardising the number of pollinators rather than the time to observe (standardised pollinator timing approach: time to n-pollinator visits) may provide more consistent accurate assessments of visitation rate, especially for studies that use gradients in visitation rates to examine the contribution of pollinators to crop pollination

Mass-migrating bumblebees: an overlooked phenomenon with potential far-reaching implications for bumblebee conservation

1. Bumblebees are one of the most commonly studied pollinators, but they are declining in large parts of their distribution. Whether bumblebees can cope with anthropogenic disturbances such as climate change and habitat loss depends largely on their dispersal capacity. While bumblebee queen dispersal is estimated to be only a few kilometres, bird migration sites have documented mass-migration events with peak migration of 70 bumblebee queens per minute, indicating that bumblebees can migrate over larger distances than previously thought. 2. The open-access database trektellen.org contains ten daily counts of &gt;1000 migrating queens past single points in the Netherlands, and one in the UK (total bumblebee records 65,430; range 1-11,142 individuals), mostly in early spring. Such mass-migration events are poorly documented in the scientific literature, and usually when describing migrations of other insects such as syrphids and social wasps. 3. Most common European bumblebee species were documented to migrate. Bumblebees were observed flying at sea, coming from sea, and flying towards the sea, showing that they can cross large water bodies. The wind direction might have helped to concentrate migration at landscape bottlenecks. On one day, bumblebee mass-migration was documented on two sites located 200 kilometres apart. Together with the concentrated and directional flight this suggests that they can migrate for several hundreds of kilometres. 4. Because most mass-migration events occur in spring, large scale shortage in suitable nesting sites may be the trigger for mass-migration (e.g. due to high queen survival or low vole numbers). Future studies should test whether this is the case, or whether bumblebees show annual seasonal migration. 5. Synthesis and applications. Much remains unclear about bumblebee migration, but it may have large consequences for the conservation of bumblebees and the ecosystem services they provide. For example, bumblebees in highly disturbed areas like agricultural landscapes may be continuously supplemented by queens from far-away productive natural areas. This suggests that large-scale conservation initiatives are required to maintain viable populations of common and endangered species. Structured observations and modern-day technology, like isotope analyses or radar monitoring, may shed light on the drivers and consequences of the overlooked phenomenon of bumblebee migration