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Most of the predatory mites belong to the order Mesostigmata, although not all mesostigmatic mites are predators. Quite a number of species are parasites and some feed on fungal material. Mesostigmata occur in a wide variety of habitats. Agricultural areas have been sampled extensively in the Netherlands, both on soil dwelling as well as on vegetation dwelling species. A number of more natural habitats are undersampled and more species for the Netherlands may be expected there. The current checklist contains 458 species, which are listed with their synonyms and occurrence records for the country. Some mesostigmatid mites are used in biological control and an additional table with native and non-native species admitted for this use is presented.

Ecological intensification aims to enhance important ecosystem processes that contribute to the delivery of the ecosystem services that underpin agricultural production allowing us to reduce our reliance on synthetic inputs. The potential of ecological intensification will depend on many factors, among the most important of which are off-field management and landscape context. These factors, and importantly the interaction between them, are likely to vary across regions and countries.Identifying off-field management approaches that are successful in enhancing ecosystem services will require assessing a range of strategies. The empirical work carried out in task 3.2 provided Original data on the effectiveness of three off-field interventions (hedgerow, set- aside and flower strips) onthe delivery of biocontrol and yield in winter cereals across different European countries. For hedgerows we found that the quality of the hedgerow (flower diversity) generally increased biodiversity of several beneficial groups of insects (e.g. butterflies, tachinids, carabids, spiders), while the delivery of ecosystems services such as pollination and pest control tended to respond more tolandscape factors (proportion of hedgerows or semi-natural habitats in general in the surrounding).For set-aside we found that this intervention increased locally the biodiversity of several beneficial insect groups (literature) but the spillover to winter wheat fields was small with no apparent benefit on the delivery of aphid biocontrol. Finally, we found that wildflower strips helped to reduce aphid pests in winter wheat fields, which, in turn, enhanced crop yield. However, this potential may only be reached in case strips are properly managed, in a way that optimizes floral diversity, and may only be relevant in agricultural landscapes with a low availability of habitat area for natural enemies.Irrespective of the intensity of the agricultural systems, the two most promising interventions to foster biocontrol and support yield in winter wheats are hedgerows and flower strips, but their effect appeared to be stronger in landscapes with low cover of existing semi-natural habitats.

Mossmites are small micro-arthropods which live in the soil. In a number of ongoing Alterra proejcts and checks of the Plant Disease Control Unit nine mossmite species have been recorded which were not yet included in the recently published Dutch checklist, nor in the supplements. The total number of mossmites species in The Netherlands is now 336. More species are to be expected in underexplored areas and habitats, some of which are to be investigated in the near future

Bestudering van materiaal uit enkele Alterra-projecten leverde negen soorten mosmijten op die nog niet waren opgenomen in de recent gepubliceerde Nederlandse naamlijst. Het totaal aantal soorten voor Nederland komt hiermee op 327.

Agricultural intensification is one of the main drivers of farmland bird declines, but effects on birds may be confounded with those of climate change. Here we examine the effects of intensification and climate change on a grassland breeding wader, the Black-tailed Godwit Limosa l. limosa, in the Netherlands. Population decline has been linked to poor chick survival which, in turn, has been linked to available foraging habitat. Foraging habitat of the nidifugous chicks consists of uncut grasslands that provide cover and arthropod prey. Conservation measures such as agri-environment schemes aim to increase the availability of chick foraging habitat but have not yet been successful in halting the decline. Field observations show that since the early 1980s, farmers advanced their first seasonal mowing or grazing date by 15 days, whereas Godwits did not advance their hatching date. Ringing data indicate that between 1945 and 1975 hatching dates advanced by about 2 weeks in parallel with the advancement of median mowing dates. Surprisingly, temperature sums at median mowing and hatching dates suggest that while the agricultural advancement before 1980 was largely due to agricultural intensification, after 1980 it was largely due to climate change. Examining arthropod abundance in a range of differently managed grasslands revealed that chick food abundance was little affected but that food accessibility in intensively used tall swards may be problematic for chicks. Our results suggest that, compared with 25 years ago, nowadays (1) a much higher proportion of clutches and chicks are exposed to agricultural activities, (2) there is little foraging habitat left when chicks hatch and (3) because of climate change, the vegetation in the remaining foraging habitat is taller and denser and therefore of lower quality. This indicates that for agri-environment schemes to make a difference, they should not only be implemented in a larger percentage of the breeding area than the current maxima of 20–30% but they should also include measures that create more open, accessible swards.

Agricultural intensification is one of the main drivers of farmland bird declines, but effects on birds may be confounded with those of climate change. Here we examine the effects of intensification and climate change on a grassland breeding wader, the Black-tailed Godwit Limosa l. limosa, in the Netherlands. Population decline has been linked to poor chick survival which, in turn, has been linked to available foraging habitat. Foraging habitat of the nidifugous chicks consists of uncut grasslands that provide cover and arthropod prey. Conservation measures such as agri-environment schemes aim to increase the availability of chick foraging habitat but have not yet been successful in halting the decline. Field observations show that since the early 1980s, farmers advanced their first seasonal mowing or grazing date by 15 days, whereas Godwits did not advance their hatching date. Ringing data indicate that between 1945 and 1975 hatching dates advanced by about 2 weeks in parallel with the advancement of median mowing dates. Surprisingly, temperature sums at median mowing and hatching dates suggest that while the agricultural advancement before 1980 was largely due to agricultural intensification, after 1980 it was largely due to climate change. Examining arthropod abundance in a range of differently managed grasslands revealed that chick food abundance was little affected but that food accessibility in intensively used tall swards may be problematic for chicks. Our results suggest that, compared with 25 years ago, nowadays (1) a much higher proportion of clutches and chicks are exposed to agricultural activities, (2) there is little foraging habitat left when chicks hatch and (3) because of climate change, the vegetation in the remaining foraging habitat is taller and denser and therefore of lower quality. This indicates that for agri-environment schemes to make a difference, they should not only be implemented in a larger percentage of the breeding area than the current maxima of 20–30% but they should also include measures that create more open, accessible swards

From 2000 to 2004, ticks were collected by dragging a blanket in four habitat areas in The Netherlands: dunes, heather, forest, and a city park. Tick densities were calculated, and infection with Borrelia burgdorferi and Anaplasma and Ehrlichia species was investigated by reverse line blot analysis. The lowest tick density was observed in the heather area (1 to 8/100 m2). In the oak forest and city park, the tick densities ranged from 26 to 45/100 m2. The highest tick density was found in the dune area (139 to 551/100 m2). The infection rates varied significantly for the four study areas and years, ranging from 0.8 to 11. 5% for Borrelia spp. and 1 to 16% for Ehrlichia or Anaplasma (Ehrlichia/Anaplasma) spp. Borrelia infection rates were highest in the dunes, followed by the forest, the city park, and heather area. In contrast, Ehrlichia/Anaplasma was found most often in the forest and less often in the city park. The following Borrelia species were found: Borrelia sensu lato strains not identified to the species level (2.5%), B. afzelii (2.5%), B. valaisiana (0.9%), B. burgdorferi sensu stricto (0.13%), and B. garinii (0.13%). For Ehrlichia/Anaplasma species, Ehrlichia and Anaplasma spp. not identified to the species level (2.5%), Anaplasma schotti variant (3.5%), Anaplasma phagocytophilum variant (0.3%), and Ehrlichia canis (0.19%) were found. E. canis is reported for the first time in ticks in The Netherlands in this study. Borrelia lusitaniae, Ehrlichia chaffeensis, and the human granylocytic anaplasmosis agent were not detected. About 1.6% of the ticks were infected with both Borrelia and Ehrlichia/Anaplasma, which was higher than the frequency predicted from the individual infection rates, suggesting hosts with multiple infections or a possible selective advantage of coinfection.