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Longitudinal studies are fundamental in the assessment of the effect of environmental factors on tick population dynamics. In this study, we use data from a 10-year study in 11 different locations in the Netherlands to gauge the effects of climatic and habitat factors on the temporal and spatial variation in questing tick activity. Marked differences in the total number of ticks were found between locations and between years. We investigated which climatic and habitat factors might explain this variation. No effects of climatic factors on the total number of ticks per year were observed, but we found a clear effect of temperature on the onset of tick activity. In addition, we found positive associations between (1) humus layer thickness and densities of all three stages, (2) moss and blackberry abundance and larval densities, and (3) blueberry abundance and densities of larva and nymphs. We conclude that climatic variables do not have a straightforward association with tick density in the Netherlands, but that winter and spring temperatures influence the onset of tick activity. Habitats with apparently similar vegetation types can still differ in tick population densities, indicating that local composition of vegetation and especially of wildlife is likely to contribute considerably to the spatial variation in tick densities.

Background The incidence of Lyme borreliosis varies over time and space through as yet incompletely understood mechanisms. In Europe, Lyme borreliosis is caused by infection with a Borrelia burgdorferi (s.l.) genospecies, which is primarily transmitted by a bite of Ixodes ricinus nymphs. The aim of this study was to investigate the spatial and temporal variation in nymphal infection prevalence of B. burgdorferi (s.l.) (NIP), density of questing nymphs (DON) and the resulting density of infected nymphs (DIN). Methods We investigated the infection rates in I. ricinus nymphs that were collected monthly between 2009 and 2016 in 12 locations in the Netherlands. Using generalized linear mixed models, we explored how the NIP, DON and DIN varied during the seasons, between years and between locations. We also determined the genospecies of the Borrelia infections and investigated whether the genospecies composition differed between locations. Results The overall NIP was 14.7%. A seasonal pattern in infection prevalence was observed, with higher estimated prevalences in the summer than in the spring and autumn. This, combined with higher nymphal densities in summer, resulted in a pronounced summer peak in the estimated DIN. Over the 7.5-year study period, a significant decrease in infection prevalence was found, as well as a significant increase in nymphal density. These two effects appear to cancel each other out; the density of infected nymphs, which is the product of NIP × DON, showed no significant trend over years. Mean infection prevalence (NIP, averaged over all years and all months) varied considerably between locations, ranging from 5 to 26%. Borrelia genospecies composition differed between locations: in some locations almost all infections consisted of B. afzelii, whereas other locations had more diverse genospecies compositions. Conclusion In the Netherlands, the summer peak in DIN is a result of peaks in both NIP and DON. No significant trend in DIN was observed over the years of the study, and variations in DIN between locations were mostly a result of the variation in DON. There were considerable differences in acarological risk between areas in terms of infection prevalence and densities of ticks as well as in Borrelia genospecies composition. Graphical Abstract

Background As part of malaria prevention and control efforts, the distribution and density of malaria mosquitoes requires continuous monitoring. Resources for long-term surveillance of malaria vectors, however, are often limited. The aim of the research was to evaluate the value of citizen science in providing insight into potential malaria vector hotspots and other malaria relevant information, and to determine predictors of malaria vector abundance in a region where routine mosquito monitoring has not been established to support vector surveillance. Methods A 1-year citizen science programme for malaria mosquito surveillance was implemented in five villages of the Ruhuha sector in Bugesera district, Rwanda. In total, 112 volunteer citizens were enrolled and reported monthly data on mosquitoes collected in their peridomestic environment using handmade carbon-dioxide baited traps. Additionally, they reported mosquito nuisance experienced as well as the number of confirmed malaria cases in their household. Results In total, 3793 female mosquitoes were collected, of which 10.8% were anophelines. For the entire period, 16% of the volunteers reported having at least one confirmed malaria case per month, but this varied by village and month. During the study year 66% of the households reported at least one malaria case. From a sector perspective, a higher mosquito and malaria vector abundance was observed in the two villages in the south of the study area. The findings revealed significant positive correlations among nuisance reported and confirmed malaria cases, and also between total number of Culicidae and confirmed malaria cases, but not between the numbers of the malaria vector Anopheles gambiae and malaria cases. At the sector level, of thirteen geographical risk factors considered for inclusion in multiple regression, distance to the river network and elevation played a role in explaining mosquito and malaria mosquito abundance. Conclusions The study demonstrates that a citizen science approach can contribute to mosquito monitoring, and can help to identify areas that, in view of limited resources for control, are at higher risk of malaria.

Background Many countries, including Rwanda, have mosquito monitoring programmes in place to support decision making in the fight against malaria. However, these programmes can be costly, and require technical (entomological) expertise. Involving citizens in data collection can greatly support such activities, but this has not yet been thoroughly investigated in a rural African context. Methods Prior to the implementation of such a citizen-science approach, a household entomological survey was conducted in October–November 2017 and repeated one year later in Busoro and Ruhuha sectors, in southern and eastern province of Rwanda, respectively. The goal was to evaluate the perception of mosquito nuisance reported by citizens as a potential indicator for malaria vector hotspots. Firstly, mosquito abundance and species composition were determined using Centers for Disease Control and Prevention (CDC) light traps inside the houses. Secondly, household members were interviewed about malaria risk factors and their perceived level of mosquito nuisance. Results Tiled roofs, walls made of mud and wood, as well as the number of occupants in the house were predictors for the number of mosquitoes (Culicidae) in the houses, while the presence of eaves plus walls made of mud and wood were predictors for malaria vector abundance. Perception of mosquito nuisance reported indoors tended to be significantly correlated with the number of Anopheles gambiae sensu lato (s.l.) and Culicidae collected indoors, but this varied across years and sectors. At the village level, nuisance also significantly correlated with An. gambiae s.l. and total mosquito density, but only in 2018 while not in 2017. Conclusions Perception of mosquito nuisance denoted in a questionnaire survey could be used as a global indicator of malaria vector hotspots. Hence, involving citizens in such activities can complement malaria vector surveillance and control.

Malaria remains a major threat to public health. Long-Lasting Insecticide-treated Nets (LLINs) and Indoor Residual Spraying (IRS) have been widely adopted as important malaria prevention and control interventions and have contributed to significant reduction in malaria incidence. However, recently malaria resurgence has been reported in different countries, including Rwanda, indicating that current attempts to control and eliminate malaria may be failing due to environmental changes and changes in human behaviour. Engaging citizens in malaria prevention and control would help them to identify and prioritize their own health concerns and be able to make appropriate decisions. A citizen science approach to monitor ecological changes by providing timely information is likely to support more effective and consistent use of malaria prevention and control interventions. However, the application of citizen science in malaria prevention and control has lagged behind when comparing with areas of disease diagnosis and treatment. In addition, the determinants of participation in such a citizen science program have not been fully analyzed. This paper presents a conceptual model of likely determinants of participation in connective action (sharing and exchange of malaria-related information), effective and consistent use of malaria preventive and control measures (LLINs and IRS) and collective action (participating in public goods for malaria prevention). The model will guide future research on behavioural and contextual factors and may enhance the effective and consistent use of malaria preventive and control interventions.

Despite the implementation of a number of interventions aimed at controlling malaria, Rwanda is experiencing a countrywide resurgence of simple malaria cases over the past five years. To support malaria control, mosquito surveillance activities, such as systematic reporting of the distribution, the diversity and the infectivity rate of malaria vectors throughout the country, have been undertaken. However, mosquito monitoring programmes are not carried out to monitor the impact of all vector control interventions or to determine the distribution of mosquito species in all areas, especially in the remote regions of the country. With a target of reducing malaria mortality by 2020, implementation of mosquito surveillance in those regions is urgently needed as well. In this paper, a Citizen science approach as a capacity resource for malaria vector monitoring for the Rwandan National Malaria Control Programme is presented. The ultimate aim is to complement existing mosquito surveillance currently in place by providing key information on the spatio-temporal distribution of mosquito nuisance and malaria vectors. This will contribute to an insight into the ecology of malaria vectors and thereby to a better understanding of malaria transmission patterns in Rwanda.

A longitudinal investigation on tick populations and their Borrelia infections in the Netherlands was undertaken between 2006 and 2011 with the aim to assess spatial and temporal patterns of the acarological risk in forested sites across the country and to assess variations in Borrelia genospecies diversity. Ticks were collected monthly in 11 sites and nymphs were examined for Borrelia infections. Tick populations expressed strong seasonal variations, with consistent and significant differences in mean tick densities between sites. Borrelia infections were present in all study sites, with a site-specific mean prevalence per month ranging from 7% to 26%. Prevalence was location-dependent and was not associated with tick densities. Mean Borrelia prevalence was lowest in January (4%), gradually increasing to reach a maximum (24%) in August. Borrelia afzelii represented 70% of all infections, with Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia valaisiana represented with 4%, 8%, and 10%, respectively. The density of infected nymphs and the proportional distribution of the four Borrelia genospecies, were significantly different between sites. The results show a consistent and significant spatial and temporal difference in acarological risk across the Netherlands.

Phenological responses of butterflies to temperature have been demonstrated in several European countries by using data from standardized butterfly monitoring schemes. Recently, phenological networks have enabled volunteers to record phenological observations at project websites. In this study, the quality of the first appearance data of butterflies from the Dutch phenological network ‘De Natuurkalender’ was examined and these data were then used to analyze trends in butterfly appearance between 2001 and 2013, the effects of climatic factors on appearance of butterflies as well as the phenological interaction of one butterfly species, Anthocharis cardamines, and its two major host plants. Although phenological networks are relatively unstructured, this study shows that data from De Natuurkalender were highly comparable to more standardized data collected by the Dutch Butterfly Monitoring Scheme. No trend in first appearance of any butterfly species was found during the time period 2001–2013. The first appearance dates of most butterflies showed, however, a clear relationship with spring temperature. Higher temperatures, especially in March and April, advanced the first appearance of butterflies. Therefore, with climatic warming in the future, earlier appearance of butterflies is expected. Although climate warming is a potential threat for phenological mismatches between different trophic levels, this study shows a similar temperature response of A. cardamines and its main host plants in the Netherlands. However, as only few phenological interactions between species are examined, further research including rarer monophagous butterfly species and their host plants is needed.

Good health and human wellbeing is one of the sustainable development goals. To achieve this goal, many efforts are required to control infectious diseases including malaria which remains a major public health concern in Rwanda. Surveillance of mosquitoes is critical to control the disease, but surveillance rarely includes the participation of citizens. A citizen science approach (CSA) has been applied for mosquito surveillance in developed countries, but it is unknown whether it is feasible in rural African contexts. In this paper, the technical and social components of such a program are described. Participatory design workshops were conducted in Ruhuha, Rwanda. Community members can decide on the technical tools for collecting and reporting mosquito species, mosquito nuisance, and confirmed malaria cases. Community members set up a social structure to gather observations by nominating representatives to collect the reports and send them to the researchers. These results demonstrate that co-designing a citizen science program (CSP) with citizens allows for decision on what to use in reporting observations. The decisions that the citizens took demonstrated that they have context-specific knowledge and skills, and showed that implementing a CSP in a rural area is feasible.

Background Malaria preventive measures, including long-lasting insecticide-treated bet nets (LLINs), indoor residual spraying (IRS), and controlling mosquito breeding sites, are key measures to achieve malaria elimination. Still, compliance with these recommended measures remains a major challenge. By applying a novel and comprehensive model for determinants of malaria prevention behaviour, this study tests how individual perceptions influence the intentions to use malaria preventive measures and explores strategies that stimulate their consistent use. Methods The study was carried out in the sectors of Ruhuha and Busoro, Rwanda during October and November 2017, and these were conducted into two phases. Phase one involved a questionnaire survey (N = 742), whereas Phase two employed a qualitative approach that included nine focus group discussions, seven key informant interviews, and three in-depth interviews. Results The findings of the quantitative study showed that participants very often use LLINs (66.6%), accept IRS (73.9%), and drain stagnant water in case of presence (62%). The intentions to use malaria preventive measures were consistently driven by perceived severity, perceived self-efficacy, perceived response efficacy, and subjective norms, and hindered by perceived barriers. The intentions were also positively associated with the actual use of LLINs, acceptance of IRS, and drainage of stagnant water. There is no evidence that either not having enough LLINs (ownership of at least one bed net in the household, here referred to as availability) or having sufficient LLINs (having one LLIN per two people in the household, here referred to as accessibility) moderated the relationship between behavioural intentions and actual use of LLINs. The qualitative study indicated that participants believed malaria risk to be high and perceived a high mosquito density. They also believed that repetitive malaria episodes are caused by the perceived low effectiveness of anti-malaria medications. Lack of LLINs increased the perceived added value of LLINs, and together with the increased malaria burden increased the perceived response efficacy. Participants highlighted the need to continuously mobilize and engage community members especially those who do not use LLINs when having one, and those who do not accept the spraying activities. Conclusion Malaria prevention interventions should target individual perceptions to enhance consistent use of malaria preventive measures. Three strategies to improve consistent use and acceptance of these measures are highlighted: (1) ensure access to LLINs and regular spraying activities, (2) community mobilization and (3) citizen engagement in malaria prevention activities.

In the scientific community, the importance of communication to society is often underestimated. Scientists and scientific organisations often lack the skills to organise such communication effectively. The Dutch citizen science phenology network Nature's Calendar has been successful in communicating to the general public via numerous newspaper articles, television appearances, presentations, websites and social media. We refer to these publications as societal publications. Due to active communication to mass media, we frequently reach millions of people. This communication helped us to involve thousands of volunteers in recording the timing of phenological events like the start of flowering, leaf unfolding and bird migration, but also several health-related events like hay fever symptoms and tick bites. In this paper, we analyse and present our experiences with the Nature's Calendar project regarding societal publications. Based on this analysis, we explain the importance of societal publications for citizen science projects and scientists in general, and we show how scientists can increase the news worthiness of scientific information and what factors and activities can increase the chances of media paying attention to this news. We show that societal publications help phenological networks by facilitating the recruitment, retention and instruction of observers. Furthermore, they stimulate the generation of new ideas and partners that lead to an increase in knowledge, awareness and behavioural change of the general public or specific stakeholders. They make projects, and scientists involved, better known to the public and increase their credibility and authority. Societal publications can catalyse the production of new publications, thereby enforcing the previous mentioned points.

Background Tick populations and tick-borne infections have steadily increased since the mid-1990s posing an ever-increasing risk to public health. Yet, modelling tick dynamics remains challenging because of the lack of data and knowledge on this complex phenomenon. Here we present an approach to model and map tick dynamics using volunteered data. This approach is illustrated with 9 years of data collected by a group of trained volunteers who sampled active questing ticks (AQT) on a monthly basis and for 15 locations in the Netherlands. We aimed at finding the main environmental drivers of AQT at multiple time-scales, and to devise daily AQT maps at the national level for 2014. Method Tick dynamics is a complex ecological problem driven by biotic (e.g. pathogens, wildlife, humans) and abiotic (e.g. weather, landscape) factors. We enriched the volunteered AQT collection with six types of weather variables (aggregated at 11 temporal scales), three types of satellite-derived vegetation indices, land cover, and mast years. Then, we applied a feature engineering process to derive a set of 101 features to characterize the conditions that yielded a particular count of AQT on a date and location. To devise models predicting the AQT, we use a time-aware Random Forest regression method, which is suitable to find non-linear relationships in complex ecological problems, and provides an estimation of the most important features to predict the AQT. Results We trained a model capable of fitting AQT with reduced statistical metrics. The multi-temporal study on the feature importance indicates that variables linked to water levels in the atmosphere (i.e. evapotranspiration, relative humidity) consistently showed a higher explanatory power than previous works using temperature. As a product of this study, we are able of mapping daily tick dynamics at the national level. Conclusions This study paves the way towards the design of new applications in the fields of environmental research, nature management, and public health. It also illustrates how Citizen Science initiatives produce geospatial data collections that can support scientific analysis, thus enabling the monitoring of complex environmental phenomena.

To the Editor: Borrelia miyamotoi is a relatively novel tickborne relapsing fever spirochete, and is a different species than B. burgdorferi sensu lato, the causative pathogen of Lyme borreliosis (1). B. miyamotoi was first isolated in 1995 from Ixodes persulcatus ticks in Japan, after which it was detected in ticks in North America, Europe, and Russia (1,2). B. miyamotoi infections among humans were first reported in Russia in 2011 (3), and in 2013 in the United States (4). Recently, the first patient infected with B. miyamotoi was reported in the Netherlands (5). Conditions reported to be associated with B. miyamotoi infection were systemic, including malaise and fever, meningoencephalitis, and neurologic symptoms. Because of the nature of these manifestations and because regular diagnostic tests for B. burgdorferi will most probably not detect B. miyamotoi infections (3,5), B. miyamotoi infections may remain undiagnosed. Nevertheless, the relationship between B. miyamotoi infection and illness is not very well established; the case-patients reported, including the patient in the Netherlands, were usually hospitalized, severely ill, and often immunocompromised (3–5). The extent to which B. miyamotoi causes infection and disease in immunocompetent persons is unknown. As a first step to indicate the population at risk for infection, we investigated human exposure to B. miyamotoi in the Netherlands. To do this, we assessed the B. miyamotoi infection rate of ticks that had bitten humans. Earlier studies included ticks collected through flagging an area (1,2); our study provides specific information about the infection rate of ticks feeding on humans. The ticks were collected from persons who reported their tick bites on the website http://www.tekenradar.nl. After removal of the ticks from the skin, the ticks were submitted to the National Institute of Public Health and the Environment. For 1,040 ticks gathered during April–June 2012, we determined tick species, stage of development, and gender by microscopic examination. We defined the degree of engorgement in 4 categories from unengorged (score 0) to fully engorged (score 3), as visually determined. To isolate DNA, we boiled the ticks with engorgement scores of 0­–1 in ammonium hydroxide (6); for ticks with engorgement scores of 2–3, we used the QIAGEN (Valencia, CA . USA) blood and tissue DNA-extraction kit (7). We used a B. miyamotoi–specific real-time PCR based on the flagellin gene for detection of the bacteria (5). Quantitative PCR-positive tick lysates were tested with a conventional PCR, which amplifies a fragment of glycerophosphodiester phosphodiesterase (glpQ) gene, to confirm the outcome (5). These PCR products were sequenced and were identical to B. miyamotoi sequences filed in GenBank ({"type":"entrez-nucleotide","attrs":{"text":"AB824855","term_id":"565410772","term_text":"AB824855"}}AB824855). We determined the presence of B. burgdorferi DNA with a duplex quantitative PCR using fragments of the outer membrane protein A gene and the flagellin B gene as targets (7). All 1,040 ticks were identified as Ixodes ricinus, the most common tick that transmits B. burgdorferi in northern Europe (8). We detected B. miyamotoi DNA in 37 ticks (3.6%) using real-time PCR targeting the flagellin gene, which was confirmed for 32 ticks (3.1%) in the conventional PCR targeting the glpQ gene. (Technical Appendix Table). In 9 of the 37 ticks positive for B. miyamotoi, B. burgdorferi was also detected. Similar to B. burgdorferi, the risk of transmission of B. miyamotoi is likely to become higher if ticks become engorged with blood; 23 of the 37 (62.2%) B. miyamotoi–infected ticks were somewhat engorged (score 1–3) and thus had such an increased risk for transmission. All glpQ sequences of the detected B. miyamotoi isolates were identical to the sequence detected in the sample from the patient reported in the Netherlands this year by Hovius et al. (5). B. burgdorferi DNA was detected in 190 ticks (18.3%) compared with 11.8% detected in a study that included ticks collected through flagging (9). Figure shows that ticks included in the study were submitted from all parts of the country; B. miyamotoi– and B. burgdorferi–positive ticks were found in almost every region. Of the ≈1 million tick bites per year in the Netherlands (10), an estimated 36,000 were by ticks that were infected with B. miyamotoi, and 183,000 were by ticks infected with B. burgdorferi. This substantial human exposure to B. miyamotoi and the reported cases in Russia, the United States, and, recently, the Netherlands (3–5) raises the question to what extent exposure to B. miyamotoi leads to human disease in the general population? These results call for the development of sensitive and specific serologic and molecular tests for B. miyamotoi to identify possible patients, which will lead to a better understanding of the clinical spectrum of B. miyamotoi–induced disease. Figure Locations of ticks collected through the website http://www.tekenradar.nl in the Netherlands during summer 2012,. Ticks included in the study were submitted from all parts of the country; ticks positive for Borrelia miyamotoi and B. burgdorferi were found ... Technical Appendix: Infection rates of Ixodes ricinus ticks with Borrelia miyamotoi and B. burgdorferi Click here to view.(17K, pdf)

Introduction: On average 23% of the European population suffers from allergic rhinitis of which pollen is a major cause. Hay fever symptom forecasts can help these patients to adapt their behaviour and to take their medication in time. We developed the LUMC hay fever forecast for grass pollen allergic patients based on local weather parameters (de Weger et al. Int J Biometeorol 2013). In this study we analysed to what extent symptom scores collected by the citizen science platform www.Allergieradar.nl (de Weger et al. Allergy 2014) are correctly predicted by the LUMC hay fever forecast. Methods: The Netherlands was divided into five regions based on similar weather conditions in order to construct region-specific hay fever forecasts. During the grass pollen season of 2014 daily symptom scores were registered by participants of Allergieradar and were grouped per region. Using multiple regression analysis, we assessed to what extent the forecasted symptom scores were related to the number of daily entries, the mean symptom scores and the interaction between the latter two. Results: The number of daily entries and registered symptom severity submitted per day via Allergieradar.nl were positively correlated with the forecasted symptom scores. The full model, including the interaction of the number of daily entries and the mean registered symptom score, explained variance of 76%. Conclusion: The LUMC hay fever forecast is for 76% in line with the symptom scores combined with the number of entries from the citizen science based internet platform Allergieradar. Therefore, hay fever symptoms experienced in allergic rhinitis patients are well predicted by the LUMC hay fever forecast.

Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-analysis has so far examined the possible lack of evidence for changes or shifts at sites where no temperature change is observed. We used an enormous systematic phenological network data set of more than 125 000 observational series of 542 plant and 19 animal species in 21 European countries (1971–2000). Our results showed that 78% of all leafing, flowering and fruiting records advanced (30% significantly) and only 3% were significantly delayed, whereas the signal of leaf colouring/fall is ambiguous. We conclude that previously published results of phenological changes were not biased by reporting or publication predisposition: the average advance of spring/summer was 2.5 days decade � 1 in Europe. Our analysis of 254 mean national time series undoubtedly demonstrates that species’ phenology is responsive to temperature of the preceding

The analysis of changes in the timing of life cycle-events of organisms (phenology) has been able to contribute significantly to the assessment of potential impacts of climate change on ecology. These phenological responses of species to changes in climate are likely to have significant relevance for socio-economic issues such as agriculture, forestry and human health and have proven able to play a role in raising environmental awareness and education on climate change. This paper presents the European Phenology Network (EPN), which aims to increase the efficiency, added value and use of phenological monitoring and research, and to promote the practical use of phenological data in assessing the impact of global (climate) change and possible adaptation measures. The paper demonstrates that many disciplines have to deal with changes in the timing of life-cycle events in response to climate change and that many different user groups are involved. Furthermore, it shows how EPN addresses issues such as (1) raising public awareness and education, (2) the integration and co-operation of existing observing systems, (3) integration and access to phenological information and (4) communication.

13 páginas, 5 figuras, The recent emergence in Europe of invasive mosquitoes and mosquito-borne disease associated with both invasive and native mosquito species has prompted intensified mosquito vector research in most European countries. Central to the efforts are mosquito monitoring and surveillance activities in order to assess the current species occurrence, distribution and, when possible, abundance, in order to permit the early detection of invasive species and the spread of competent vectors. As active mosquito collection, e.g. by trapping adults, dipping preimaginal developmental stages or ovitrapping, is usually cost-, time- and labour-intensive and can cover only small parts of a country, passive data collection approaches are gradually being integrated into monitoring programmes. Thus, scientists in several EU member states have recently initiated programmes for mosquito data collection and analysis that make use of sources other than targeted mosquito collection. While some of them extract mosquito distribution data from zoological databases established in other contexts, community-based approaches built upon the recognition, reporting, collection and submission of mosquito specimens by citizens are becoming more and more popular and increasingly support scientific research. Based on such reports and submissions, new populations, extended or new distribution areas and temporal activity patterns of invasive and native mosquito species were found. In all cases, extensive media work and communication with the participating individuals or groups was fundamental for success. The presented projects demonstrate that passive approaches are powerful tools to survey the mosquito fauna in order to supplement active mosquito surveillance strategies and render them more focused. Their ability to continuously produce biological data permits the early recognition of changes in the mosquito fauna that may have an impact on biting nuisance and the risk of pathogen transmission associated with mosquitoes. International coordination to explore synergies and increase efficiency of passive surveillance programmes across borders needs to be established., This research was supported by Science and Technology Support Program of Sichuan Province (Grant No. 2015SZ0201), Special Fund for Agroscientific Research in the Public Interest (Grant No. 201203062) and Chang-jiang Scholars and the Innovative Research Team in University (Grant No. IRT0848).

We determined whether climate change in the Netherlands has caused phenological changes since 1868. We analysed over 150,000 plant phenological observations of 320 plant species, obtained by four volunteer networks and one series collected by Mr. Braaksma. With the network data, we compared the timing of life cycle events in three different periods: 1894–1932 (Period 1), 1940–1968 (Period 2) and 2001–2010 (Period 3). For the Braaksma series, we compared the periods 1953–1968 (Period A) with 1969–1992 (Period B). We conclude that until the beginning of the 1990s, there have been no significant changes in the timing of life cycle events. The timing of life cycle events in Period 3 showed an average advance of flowering, leaf unfolding and fruit ripening of 14 days compared with Period 1 and 13 days compared with Period 2. Some species have advanced up to over 35 days. Autumn events occurred up to an average of 7 days later in Period 3 compared to earlier periods. This study shows that, based on network data, changes in climate explain on average 66 % of the variation in timing of phenological events from year to year. For the Braaksma data, this is 38 %. The expected future changes in climate will undoubtedly result in a further lengthening of the growing season. We believe that phenological networks, supported by thousands of volunteers, are needed to quantify, analyse, predict and communicate these phenological changes so various sectors in society can adapt to these changes and prevent significant socio-economic impacts.

Background Between 1994 and 2009, a threefold increase has been observed in consultations of general practitioners for tick bites and Lyme disease in The Netherlands. The objective of this study was to determine whether an increase in the number of questing ticks infected with B. burgdorferi sensu lato is a potential cause of the rise in Lyme disease incidence. Methods Historic data on land usage, temperature and wildlife populations were collected and analyzed together with data from two longitudinal field studies on density of questing ticks. Effective population sizes of Borrelia burgdorferi s.l. were calculated. Results Long-term trend analyses indicated that the length of the annual tick questing season increased as well as the surface area of tick-suitable habitats in The Netherlands. The overall abundances of feeding and reproductive hosts also increased. Mathematical analysis of the data from the field studies demonstrated an increase in mean densities/activities of questing ticks, particularly of larvae between 2006 and 2009. No increase in infection rate of ticks with Borrelia burgdorferi sensu lato was found. Population genetic analysis of the collected Borrelia species points to an increase in B. afzelii and B. garinii populations. Conclusions Together, these findings indicate an increase in the total number of Borrelia-infected ticks, providing circumstantial evidence for an increase in the risk of acquiring a bite of a tick infected with B. burgdorferi s.l. Due to the high spatiotemporal variation of tick densities/activities, long-term longitudinal studies on population dynamics of I. ricinus are necessary to observe significant trends.

Climate change may induce alterations in the start and duration of the pollen season. Future changes in climate are likely to significantly advance the start of the pollen season and change the pollen concentration in the atmosphere. These changes may have consequences for the use and costs of medication for allergic rhinitis (AR). The aim of the study presented here was to investigate the effects of changes in the pollen concentration on medication dispensing and medication costs. Weekly pharmacy dispensing data on medication for hay fever and the associated costs were modeled using weekly pollen counts for different species during the period 2001–2005. Both the pollen counts and the pharmacy data have been collected from the Netherlands. The majority of the annually dispensed AR-medication appeared not to be directly related to pollen counts and was dispensed outside the pollen season. However, the large weekly variation in AR medication dispersion and costs could be attributed to a substantial degree to grass, Birch and Alder pollen concentration in the atmosphere. This significant impact of weekly pollen counts on the variation in medication dispensing suggests the importance of changes in pollen concentration in determining the incidence of symptoms. Climate change induced changing pollen seasons will make it more difficult for patients and health professionals to anticipate the need for AR medication.

Climate change possibly affects public health in the Netherlands, including changes in (a) temperature-related effects, heat stress and air pollution, (b) allergies, (c) vector borne infectious disease, and (d) food- and waterborne infectious disease. Due to many prevailing uncertainties, opinions differ regarding the exact size of the expected health risks and the speed at which these might occur, as well as regarding to what degree society would need to or could adapt to these potential health effects. Thus, the gaps in our knowledge are substantial. Scientists and experts are clearly concerned about the limited amount of attention being paid to health effects of climate change in the Netherlands. In response, a proposal for a research programme 'Klimaatverandering en Gezondheid' ('Climate change and health') has been developed over the past year.

In this chapter I provided a qualitative overview of how phenological changes will strongly influence human well-being through changes in primary production sectors depending on natural productivity, including agriculture, forestry and fisheries, and the public health sector. Farmers, commercial enterprises, patients, doctors and policy makers have to adapt pro-actively to cope with, prevent or reduce potential negative impacts. Adaptation should be relatively easy in most cases because people have to ‘only’ change the timing of their activities. However, pro-active adaptation is currently often unfeasible because stakeholders do not know what phenological changes will happen where and when. They also are not aware of the ecological and socio-economic consequences of such phenological changes. They seem to miss a sense of urgency to act. Furthermore, they miss an understanding on whether, how and when to respond in order to prevent (further) negative impacts or to benefit from the emerging changes.

An important issue in the debate about the use and conservation of natural ecosystems is the degree to which these ecosystems and their functions should be considered 'critical'. This paper presents some guidelines to determine the criticality of natural capital, based on two main criteria. The first criterion is the 'importance' of natural ecosystems (ecological, socio-cultural and economic) and the second is the degree of 'threat' based on the quantity and quality of the (remaining) natural areas in a given region. It is argued that the two criteria are complementary and need to be taken into account simultaneously when determining the criticality of natural capital. Finally, the paper presents and discusses some possibilities for the development of a (critical) natural capital index for Europe. (C) 2002 Elsevier Science B.V. All rights reserved.

In the last decade it has become clear that the timing of many phenological processes, like the start of flowering and leaf unfolding in spring, have changed. The increase in temperature is believed to be the main cause. The earlier start of flowering will have consequences for the start of the pollen season, and thus for the start of the hay fever season. Millions of people world-wide will therefore experience the impact of climate change in their daily lives during spring and summer. In this paper we analyse the relation between climate parameters, especially temperature, and the start of the pollen season in the western part of the Netherlands based on daily pollen counts of the Leiden University Medical Centre and temperature measurements from 1969 till 2000 by the Royal Netherlands Meteorological Institute in De Bill. The results indicate that there is a strong correlation between temperature and start of the pollen season. An advance of the start of the pollen season of 3 to 22 days has been observed. The potential future changes in the start of the pollen season under climate change scenarios are also discussed. Copyright (C) 2002 Royal Meteorological Society.

Although the effects of climate change on biodiversity are increasingly evident by the shifts in species ranges across taxonomical groups, the underlying mechanisms affecting individual species are still poorly understood. The power of climate envelopes to predict future ranges has been seriously questioned in recent studies. Amongst others, an improved understanding of the effects of current weather on population trends is required. We analysed the relation between butterfly abundance and the weather experienced during the life cycle for successive years using data collected within the framework of the Dutch Butterfly Monitoring Scheme for 40 species over a 15-year period and corresponding climate data. Both average and extreme temperature and precipitation events were identified, and multiple regression was applied to explain annual changes in population indices. Significant weather effects were obtained for 39 species, with the most frequent effects associated with temperature. However, positive density-dependence suggested climatic independent trends in at least 12 species. Validation of the short-term predictions revealed a good potential for climate-based predictions of population trends in 20 species. Nevertheless, data from the warm and dry year of 2003 indicate that negative effects of climatic extremes are generally underestimated for habitat specialists in drought-susceptible habitats, whereas generalists remain unaffected. Further climatic warming is expected to influence the trends of 13 species, leading to an improvement for nine species, but a continued decline in the majority of species. Expectations from climate envelope models overestimate the positive effects of climate change in northwestern Europe. Our results underline the challenge to include population trends in predicting range shifts in response to climate change. Electronic supplementary material The online version of this article (doi:10.1007/s00442-011-2007-z) contains supplementary material, which is available to authorized users.