Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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The wild life of tick-borne pathogens
Hofmeester, Tim R. - \ 2016
University. Promotor(en): Herbert Prins, co-promotor(en): Sip van Wieren. - Wageningen : Wageningen University - ISBN 9789462579699 - 224
ixodes ricinus - metastigmata - life cycle - tickborne diseases - disease vectors - mammals - birds - hosts - population ecology - tick infestations - host parasite relationships - levenscyclus - ziekten overgebracht door teken - vectoren, ziekten - zoogdieren - vogels - gastheren (dieren, mensen, planten) - populatie-ecologie - tekenbesmettingen - gastheer parasiet relaties

Diseases that are transmitted by arthropod vectors from animal hosts to humans – so called zoonotic vector-borne diseases – have increased in incidence in the last decades. In North America and Europe, tick-borne pathogens cause the majority of vector-borne diseases, including Lyme borreliosis and tick-borne encephalitis. The pathogens causing these diseases are transmitted by tick species within the Ixodes ricinus complex. These are generalist ticks that have a multi-year lifecycle with three active stages, larva, nymph and adult. Each stage passively waits for a vertebrate host by questing in the vegetation. Once a host is encountered these ticks feed on the host for several days sucking blood, after which they detach and moult to the next stage or lay eggs. Although these ticks spend the majority of their life in the vegetation, the availability of hosts is an important determinant of tick densities.

In Europe, the Sheep tick (Ixodes ricinus) is the most important vector for tick-borne pathogens. These pathogens include Borrelia burgdorferi sensu lato (s.l.), the causative agent of Lyme borreliosis, Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis, Borrelia miyamotoi, the causative agent of acute febrile illness and Candidatus Neoehrlichia mikurensis, the causative agent of neoehrlichiosis. There are several genospecies within the B. burgdorferi s.l. complex, among which B. afzelii, B. bavariensis, B. garinii, B. lusitaniae, B. spielmanii, and B. valaisiana are found in questing ticks and patients in the Netherlands. All of these pathogens are maintained and amplified by vertebrate hosts. Host species differ in their ability to transmit the different pathogens (reservoir competence), as well as in their competence for ticks. Therefore, it has been hypothesized that changes in vertebrate assemblage composition can change tick-borne pathogen dynamics and thereby tick-borne disease risk, where a decrease in host species diversity might lead to an increased disease risk, the so-called dilution effect of host species richness hypothesis.

In his thesis, Tim Hofmeester describes his research on the role of different vertebrate host species in maintaining I. ricinus populations and in infecting I. ricinus larvae with different tick-borne pathogens. By performing a systematic review, Hofmeester found that for both mammals and birds, there was a positive correlation between host body mass and tick burden for the different stages. Nymphal burden was positively correlated with infection prevalence with B. burgdorferi s.l. in hosts, which was again positively correlated with the average number of larvae that got infected with B. burgdorferi s.l. while feeding on a host. He also showed that the majority of I. ricinus individuals of the three stages (larva, nymph and adult) feed on only a few vertebrate host species (rodents, thrushes and deer, respectively). Using camera traps, Hofmeester showed that the presence of deer, such as Roe deer and Red deer, was a more important determinant of I. ricinus density than the number of deer available to ticks in twenty forested areas in the Netherlands. Ixodes ricinus densities were significantly reduced after two years of excluding deer by fencing four 0.75 ha forest plots in a forest near Apeldoorn, the Netherlands. Therefore, tick-borne disease risk can be reduced by placing fences around small forested areas with a high recreational pressure.

Hofmeester showed that tick burdens on rodents were higher in areas with large numbers of deer, while they were lower in areas with large numbers of carnivores. These differences in tick burden on rodents between areas were strongly correlated to the number of questing nymphs in the vegetation that were infected with tick-borne pathogens that are transmitted by rodents. This implies that changes in vertebrate assemblage can lead to cascading effects on rodent-transmitted tick-borne disease risk, via larval burden on rodents. Furthermore, Hofmeester found that the percentage of ticks infected with a specific pathogen was correlated to the number of animals in an area that could transmit this pathogen, while this percentage decreased with the number of animals that could not transmit this pathogen. These parameters were, however, not correlated to species richness, something that was expected based on the dilution effect of species richness hypothesis. Therefore, there is no support for a dilution effect of species richness on tick-borne pathogens in the Netherlands.

In his synthesis, Hofmeester presents a mathematical model in which the importance of spatial behaviour of hosts for tick-borne pathogens is shown and he proclaims the need for the integration of the field of behavioural ecology into disease ecology to better understand the effect of changes in vertebrate assemblages on pathogen prevalence and ultimately, disease risk. The data presented in this thesis show that it is not host diversity but the presence, abundance and behaviour of specific host species that drives tick-borne pathogen dynamics (identity effect). Vertebrate species change their behaviour in the presence or absence of predators and competitors. Hofmeester shows that this, theoretically, can have a major influence on the density of infected nymphs in the vegetation. Therefore, behavioural changes of reservoir-competent hosts should be taken into account when modelling the effect of changes in vertebrate assemblage composition on tick-borne disease risk.

The behaviour of vertebrate species in Europe is changing, as multiple species have adapted to human-dominated and fragmented landscapes. The adaptation of small mammals, thrushes and deer to fragmented landscapes might be one of the driving factors behind the increase in tick-borne disease incidence in Europe. A further adaptation of important host species to urbanized landscapes might be expected as these are the safest areas for vertebrate species trying to avoid predation. This might result in an increase in population density of reservoir-competent host species in urban areas with a corresponding increase in tick-borne pathogen prevalence and therefore, tick-borne disease risk.

Concluding, our world is changing and as a consequence vertebrate assemblages are also changing. This may lead to changes in I. ricinus density and infection prevalence with tick-borne pathogens. From the studies presented in his thesis Hofmeester concludes that the abundance and behaviour of several host species (e.g., Bank vole, Blackbird, Red deer, Red fox, Roe deer, and Wood mouse) determines tick-borne disease risk. Therefore, studying the drivers of animal abundance and behaviour related to ticks and pathogens will be the next step in better understanding and describing tick-borne disease risk. The ecology of tick-borne pathogens is very complex and targeting vertebrate hosts for intervention strategies will be both inefficient and costly due to the intricate interplay between multiple vertebrate host species. Therefore, Hofmeester concludes that prevention of tick bites is the best way to reduce tick-borne disease incidence.

Maintenance of Borrelia burgdorferi s.l. diversity in enzootic cycles
Swart-Coipan, Elena - \ 2016
University. Promotor(en): Willem Takken; Herbert Prins, co-promotor(en): H. Sprong. - Wageningen : Wageningen University - ISBN 9789462579576 - 180
borrelia burgdorferi - life cycle - tickborne diseases - metastigmata - ixodes ricinus - disease vectors - rodents - mammals - genetic analysis - multilocus sequence typing - lyme disease - levenscyclus - ziekten overgebracht door teken - vectoren, ziekten - knaagdieren - zoogdieren - genetische analyse - multi-locus sequentie typering - lyme-ziekte

Lyme borreliosis is the most prevalent vector-borne disease in the temperate regions of the northern hemisphere. The bacteria that cause it are members of the Borrelia burgdorferi sensu lato complex, a group of spirochaetes which are transmitted by hard ticks of the Ixodes ricinus complex. In several European countries, including The Netherlands, the incidence of Lyme borreliosis has been on the rise for the last decades. The acarological risk of human infection with Borrelia burgdorferi s.l. has been defined as the density of infected questing nymphs. This definition assumes that the distribution of the various genospecies of Borrelia in Lyme borreliosis is reflected in their distribution in questing ticks; furthermore, it assumes that all Borrelia genospecies are considered equally hazardous for humans. In order to define effective intervention strategies for controlling the disease, more insight in the transmission dynamics of tick-borne pathogens, both between animals and ticks, but also from ticks to humans is needed. As part of a Dutch research programme – “Shooting the messenger” – this PhD thesis focussed on linking the transmission cycles of Lyme spirochaetes to the different clinical manifestations of Lyme borreliosis. To that end, I explored aspects of the ecology and molecular adaptations of B. burgdorferi s.l. at various scales, from complex to genospecies level.

The ecological adaptations of B. burgdorferi s.l. are underpinned by a complex genomic structure and gene expression, with large genetic variation among and within the genospecies. In Chapter 3, we prove that the 5S-23S rDNA intergenic spacer (IGS) is a suitable molecular marker for identification of B. burgdorferi s.l. to genospecies level, but also to characterize the genetic diversity at intragenospecies level and to detect genetic differentiation among the subpopulations of Borrelia. Consequently, we used this marker in combination with other genetic markers, in the studies addressing the genetic diversity of Borrelia in small mammals and humans.

The main transmission route of these bacteria is the interstadial one, from larvae to nymphs and from nymphs to adult ticks. Larvae of I. ricinus can become infected during a blood meal from an infected host and during a blood meal in the vicinity of an infected nymph feeding on a host, a process known as co-feeding. The infected engorged larvae then moult into infected nymphs, which can transmit the spirochaetes to new hosts. The same process is repeated in the next developmental stage – nymph to adult. Thus, the maintenance of the bacteria in enzootic cycles is dependent on various species of vertebrates and the ticks that feed on them. In order to identify the main vertebrate hosts responsible for the maintenance of B. burgdorferi in enzootic cycles, but also for feeding I. ricinus ticks, we conducted a meta-analysis on literature data (Chapter 2). Our quantification method suggests that only a few host species, which are amongst the most widespread species in the environment (rodents, thrushes and deer), feed the majority of I. ricinus individuals and that rodents infect the majority of I. ricinus larvae with B. burgdorferi s.l.. The increase in distribution and abundance of these species, could be one of the main causes for the increase in Lyme borreliosis incidence in Europe in recent decades.

While at genospecies level, there is host specificity, with B. afzelii associated with rodents and B. garinii with birds, we wanted to see if the same holds true at intragenospecies level, for the various genotypes of Borrelia. Chapter 4 focuses on the rodents, which were identified in the literature meta-analysis as being the main hosts for I. ricinus larvae as well as for Borrelia afzelii. We tested the multiple niche polymorphisms hypothesis, using IGS, dbpA and ospC as molecular markers for typing B. afzelii genotypes in fed larvae collected from rodents in various areas in The Netherlands. Despite the high genetic diversity within B. afzelii, there was no difference between wood mice and bank voles in the number and types of B. afzelii haplotypes they transmit. Additionally, we compared the quantitative role of bank voles and wood mice in B. afzelii and Neoehrlichia mikurensis maintenance, another emerging tick-borne pathogen in Europe. Neoehrlichia mikurensis prevalence was positively associated with B. afzelii. Mathematical models including tick burden and infection prevalence indicated that bank voles are better amplifiers of these two bacteria than wood mice. Our study suggests that wood mice and bank voles differ in their contribution to the dynamics of B. afzelii, and possibly other TBP, in questing ticks but not in their contribution to the genetic diversity of these microorganisms.

The density of the vertebrate hosts and the feeding preferences of the ticks should determine the prevalence of B. burgdorferi s.l. genospecies in questing ticks. We address this topic in Chapter 5, by testing 5,570 questing I. ricinus nymphs from 22 different areas in The Netherlands. We found an overall prevalence of 11.8% for B. burgdorferi s.l., with large and consistent variations among the various locations. As expected based on the results of Chapter 2, Borrelia afzelii was predominant (6.7 % of the questing ticks) among the B. burgdorferi s.l. genospecies. It was followed by B. garinii/B. bavariensis (1.5 %), B. valaisiana (1.2 %), and B. burgdorferi sensu stricto (0.2 %). We noticed that, over the usual range of questing ticks’ densities, the density of infected ticks is increasing with the overall density of questing ticks, and a downward trend might be observed only for questing tick densities of over 200/100 m2. This indicates that the density of questing nymphs is the main driver of the acarological risk of human exposure to B. burgdorferi s.l.

We also screened for the presence of other tick-borne pathogens that have previously been detected in questing ticks in The Netherlands: Rickettsia helvetica, Anaplasma phagocytophilum, Neoehrlichia mikurensis and several Babesia spp. (Chapter 5). To test whether these pathogens might share similar enzootic cycles we looked for patterns of coinfection and seasonal dynamics of infection in questing I. ricinus nymphs. One-third of the Borrelia-positive ticks were infected with at least one other pathogen. Coinfection of B. afzelii with N. mikurensis and with Babesia spp. occurred significantly more often than single infections, indicating the existence of mutual reservoir hosts. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of their coinfections with B. burgdorferi s.l. underline the need to consider them when evaluating the risks of infection and subsequently the risk of disease following a tick bite.

Chapter 6 addresses the pathogenicity of B. burgdorferi s.l. genospecies and genotypes for humans, using the eight multilocus sequence typing scheme housekeeping genes (MLST) and IGS as molecular markers. The frequency of the Borrelia spp. in humans is compared to the frequency in questing ticks to assess the infectivity of the various genospecies and genotypes. The fraction of STs that were isolated from human samples was significantly higher for the genospecies that are known to be maintained in enzootic cycles by mammals (B. afzelii, B. bavariensis, and spielmanii) than for genospecies that are maintained by birds (B. garinii and B. valaisiana) or lizards (B. lusitaniae). Just as in questing ticks, B. afzelii was the most prevalent Borrelia in in human Lyme borreliosis. Borrelia afzelii was associated with acrodermatitis chronica atrophicans, while B. garinii and B. bavariensis were associated with neuroborreliosis. Despite its high incidence in ticks and erythema migrans, in terms of disease burden (as measured by disability-adjusted life year), B. afzelii is of least concern for public health. Other Borrelia spirochaetes that are rarely found in questing I. ricinus ticks, such as B. bavariensis, seem to be responsible for most of the neuroborreliosis cases – a more severe clinical symptom of Lyme borreliosis. This implies that the prevalence of B. burgdorferi s.l. in questing ticks does not necessarily reflect the incidence of human Lyme borreliosis. We found six multilocus sequence types that were significantly associated with clinical manifestations in humans and five IGS haplotypes that were associated with the human Lyme borreliosis cases. While IGS could perform just as well as the housekeeping genes in the MLST scheme for predicting the infectivity of B. burgdorferi s.l., the advantage of MLST is that it can also capture the differential invasiveness of the various STs.

In this thesis, I have identified the most important vertebrate hosts for maintenance of B. burgdorferi s.l. in enzootic cycles. I have also shown that their density is reflected in the prevalence of B. burgdorferi s.l. in questing ticks. The comparative study of questing ticks and Lyme borreliosis indicated that some of the Borrelia genospecies have similar prevalences in the two sources. The findings in my thesis indicate, thus, that there is a link between the density of suitable hosts for ticks and Borrelia spp., the density of infected ticks and the distribution of the B. burgdorferi s.l. genospecies in Lyme borreliosis. There are exceptions, however, that cannot be explained by this simple thread line. Such a situation is the perceived association of B. bavariensis with rodents that is not reflected by its extremely low prevalence in questing ticks. Furthermore, this low prevalence cannot explain the overrepresentation of B. bavariensis in Lyme borreliosis. As result of the study of pathogenicity of the various Borrelia genospecies and genotypes, I suggest the separate hazard assignment for the Borrelia genospecies; this, in combination with the exposure (prevalence in questing ticks) would allow for individual genospecies/genotypes risk assessment. The findings in this thesis stress the importance of both ecological and clinical studies for addressing the public health issue of Lyme borreliosis.

BioScore 2 - Plants & Mammals : background and pre-processing of distribution data
Hennekens, S.M. ; Hendriks, J.M. ; Ozinga, W.A. ; Schaminee, J.H.J. ; Santini, L. - \ 2015
Wageningen : Statutory Research Tasks Unit for Nature & the Environment (WOt-technical report 50) - 221 p.
plants - mammals - biogeography - regression analysis - models - biodiversity - data collection - habitats - planten - zoogdieren - biogeografie - regressieanalyse - modellen - biodiversiteit - gegevens verzamelen
This report highlights the background and pre-processing of the distribution of plant species, habitats and mammal species. For plants a selection of about 900 taxa has been made, based on 45 Annex I habitat types, which represent a substantial part of European natural and semi-natural vegetation. For animals all species existing in Europe have been taken into account. The data covers more or less all EU28 countries and is pre-processed in three steps to feed the BioScore 2 model. In the first step for each species or habitat type a climate/soil model has been created by using Boosted Regression Models (GBM). On the basis of these models presence/absence maps are derived to define the distribution range of the species/habitat types. In the second step additional knowledge was brought in to further specify the potential habitat within the distribution range, by laying an explicit mask over it, selecting only those land use types (land cover classes) suitable for the occurrence of the habitat type or species. In the third step the effect of human-induced pressures on habitat quality and species occurrence/abundance within the suitable habitats in the calculated distribution ranges was taken into account. The dose-effect relations were calculated on the basis of Generalized Linear Models (GLM). All outcomes of the three steps have been further used by the Netherlands Environmental Assessment Agency (PBL) to set up the BioScore 2 model.
Gunstige referentiewaarden voor populatieomvang en verspreidingsgebied van soorten van bijlage II, IV en V van de Habitatrichtlijn
Ottburg, F.G.W.A. ; Swaay, C.A.M. van - \ 2014
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu, Wageningen UR (WOt-rapport 124)
amphibia - lepidoptera - vissen - zoogdieren - ongewervelde dieren - mossen - korstmossen - reptielen - populatiebiologie - habitatrichtlijn - fishes - mammals - invertebrates - mosses - lichens - reptiles - population biology - habitats directive
This report presents the Favourable Reference Values for population size and range for the species listed in Annexes II, IV and V of the EU Habitats Directive. These reference values are used to assess the conservation status of species as required by Article 17 of the Habitats Directive. They were determined according to a protocol (checklist) and based on scientific information. Where the required scientific information was not readily available, expert judgement was used to fill the gaps. When determining the reference values, experts on each of the species groups were enlisted from the various voluntary conservation organisations, IMARES Wageningen UR (Texel and IJmuiden) and Alterra Wageningen UR. In addition, two extra questions were answered on how these reference values can be maintained or achieved, and the potential influence of climate warming.
Using Minimum Area Requirements (MAR) for assemblages of mammal and bird species in global biodiversity assessments
Verboom, J. ; Snep, R.P.H. ; Stouten, J. ; Pouwels, R. ; Pe’er, G. ; Goedhart, P.W. ; Adrichem, M.H.C. van; Alkemade, J.R.M. ; Jones-Walters, L.M. - \ 2014
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-paper 33) - 22
habitatfragmentatie - biodiversiteit - fauna - zoogdieren - vogels - landschapsecologie - habitat fragmentation - biodiversity - mammals - birds - landscape ecology
Habitat loss, fragmentation and degradation are important factors in the decline of biodiversity worldwide. It is important to be able to evaluate the success of policies at different levels, including, increasingly, the global level. Whilst attention has been given to the development of predictive models that focus on individual species within biogeographic regions or smaller areas, however, to assess the impact of land-use change and policy measures on biodiversity at global level, there is an urgent need for generic tools (models, algorithms, databases). In this paper we test the potential of a generic tool, as part of the GLOBIO model, for assessing the impact of habitat loss and fragmentation. It combines existing data for the minimum viable populations of terrestrial bird and mammal species with knowledge of individual area requirements to derive estimates of their minimum area requirements (MAR). This approach focuses on comparing the minimum area requirements (MAR) to the natural habitat areas, assuming that below a certain threshold populations are no longer viable and the species assembly will eventually be reduced. The relationship between nature area and percentage of species meeting Minimum Area Requirements appears to be log-linear between 10 km2 and 10 000 km2 for conservation priority species and has the form Y=-15.45 + 28.61* LOG(AREA). Our results suggest that many existing parks and reserves might be too small for the long-term viability of species that they are meant to preserve. Applying this relationship to a global land cover dataset reveals that substantial proportions of mammal and bird species occur in areas that fail to cover sufficient space to support long term viable populations. This applies even at current state, especially for those areas of the globe where rapid urbanisation and agricultural expansion have taken place and are anticipated to proceed.
Nederlandse biodiversiteit : Hoe belangrijk is het stedelijk gebied?
Lahr, J. ; Lammertsma, D.R. ; Bijlsma, R.J. ; Weeda, E.J. ; Buij, R. ; Snep, R.P.H. - \ 2014
Landschap : tijdschrift voor Landschapsecologie en Milieukunde 31 (2014)4. - ISSN 0169-6300 - p. 195 - 203.
stedelijke ecologie - soortendiversiteit - vogels - vegetatie - zoogdieren - insecten - habitats - stedelijke gebieden - urban ecology - species diversity - birds - vegetation - mammals - insects - urban areas
Veel soorten in Nederland vinden in de stad een geschikt leefmilieu, maar hoeveel soorten zijn werkelijk afhankelijk van het stedelijk gebied? Om deze vraag te beantwoorden is een steekproef uit het Nederlands Soortenregister voorgelegd aan een aantal taxonomische-en ecologische deskundigen. Zij hebben de getrokken soorten beoordeeld op hun afhankelijkheid van het stedelijk gebied voor de instandhouding van de populatie. Daarnaast is dat belang voo alle soorten van de Vogel- en Habitatrichtlijn afzonderlijk bepaald.
Onderzoek naar inheemse wilde fauna, verslag over 2013
Tulden, P.W. van - \ 2014
Lelystad : Central Veterinary Institute (Rapport / Central Veterinairy Institute 14/CVI0014) - 31
fauna - wild - vogels - vissen - zoogdieren - toxicologie - pathologie - doodsoorzaken - monitoring - wildlife - birds - fishes - mammals - toxicology - pathology - causes of death
Met betrekking tot een aantal opgedragen Wettelijke Onderzoekstaken (WOT) treedt het Central Veterinairy Institute op als Nationaal Referentie Laboratorium (NRL) voor aangifteplichtige virale, parasitaire, protozoaire en bacteriële ziekten, TSE’s en antimicrobiële resistentie. Dit verslag geeft een overzicht van onderzoek aan de dieren, die opgestuurd zijn naar het CVT. Enkele cijfers: 137 inzendingen in het kader van het wettelijke wilde fauna onderzoek. Maar ook 188 kadavers, 6 levende watervogels en 27 monsters verdacht materiaal. De kadavers zijn te verdelen in 65 roofvogels, 70 watervogels, 13 overige vogels, 26 zoogdieren en 14 vissen. Hier kon van 115 van de 188 kadavers de doodsoorzaak worden achterhaald. De meest vastgestelde doodsoorzaken zijn trauma, vergiftiging, uitputting, afschot en botulisme, afhankelijk van de diercategorie.
Dosssier : Wolven
Jansen, G.J. ; Groot Bruinderink, G.W.T.A. ; Jansman, H.A.H. - \ 2014
Wageningen : Wageningen UR
fauna - zoogdieren - migratie - lupus vulgaris - wildbeheer - wetenschappelijk onderzoek - oost-nederland - wolven - mammals - migration - wildlife management - scientific research - east netherlands - wolves
Overzicht van onderzoek naar de mogelijke komst van de wolf naar Nederland.
Infrastructurele knelpunten voor de otter : overzicht van verkeersknelpunten met mate van urgentie voor het nemen van mitigerende maatregelen
Kuiters, A.T. ; Lammertsma, D.R. - \ 2014
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2513) - 69
lutra lutra - migratie - zoogdieren - habitatfragmentatie - wegen - verkeersongevallen - habitats - inventarisaties - migration - mammals - habitat fragmentation - roads - traffic accidents - inventories
De afgelopen jaren zijn op veel plaatsen mitigerende maatregelen genomen om leefgebieden veiliger te maken voor de otter en de kans op verkeersslachtoffers te beperken. Echter, het aantal verkeersslachtoffers neemt ieder jaar toe, deels omdat bestaande voorzieningen in leefgebieden tekort schieten, deels omdat de otter zich aan het verspreiden is naar nieuwe leefgebieden. Om het aantal slachtoffers terug te dringen is het dringend noodzakelijk om op korte termijn verdere maatregelen te nemen. Op verzoek van het ministerie van EZ is een inventarisatie gemaakt van alle verkeersknelpunten binnen en tussen de huidige otterleefgebieden (situatie voorjaar 2013), zijn deze geprioriteerd en zijn oplossingsrichtingen beschreven.
Aerial surveys of marine mammals and other fauna around Aruba, Curacao and Bonaire, November 2013
Geelhoed, S.C.V. ; Janinhoff, N. ; Verdaat, J.P. ; Bemmelen, R.S.A. van; Scheidat, M. - \ 2014
Den Burg : IMARES (Report / IMARES Wageningen UR C012/14) - 22
luchtkarteringen - fauna - zoogdieren - inventarisaties - mariene gebieden - caribisch gebied - aerial surveys - mammals - inventories - marine areas - caribbean
In November 2013 aerial surveys were conducted for the first time in the Exclusive Economic Zone of Aruba, Curaçao and Bonaire to evaluate aerial surveys as a tool for marine mammal surveys in these waters, and to assess the distribution and abundance of marine mammals. A secondary aim of these surveys was to collect data on the occurrence of other megafauna (e.g. sharks, rays, turtles) and seabirds. Marine mammals were assessed using distance sampling methods; for other species a strip transect method was applied.
Meer teken in de natuur : een goed teken?
Sprong, H. ; Takken, W. - \ 2013
Zoogdier 24 (2013)2. - ISSN 0925-1006 - p. 1 - 4.
tekenbesmettingen - natuurgebieden - fauna - gastheer parasiet relaties - zoogdieren - tick infestations - natural areas - host parasite relationships - mammals
Veel natuurliefhebbers weten dat teken de ziekte van Lyme kunnen overbrengen. Dat zoogdieren daarbij een dubbele rol spelen, is veel minder bekend. Toename van de ziekte heeft gezorgd voor meer onderzoek naar de ziekte en de teken. Wat weten we nu over de overdracht van die ziekte, de rol van zoogdieren hierin en de impact van meer natuur in Nederland
Schadeveroorzakende zoogdiersoorten in Nederland : inzicht in de betrouwbaarheid van aantalsbepalingen
Groot Bruinderink, G.W.T.A. ; Goedhart, P.W. ; Lammertsma, D.R. ; Dekker, J.J.A. - \ 2013
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2426)
fauna - inventarisaties - zoogdieren - schadelijke dieren - hoefdieren - monitoring - tellen - methodologie - gegevensanalyse - nederland - inventories - mammals - noxious animals - ungulates - counting - methodology - data analysis - netherlands
Het Faunafonds heeft Alterra gevraagd voorstellen te doen om de kwaliteit van de gehanteerde schattingen van populaties van zoogdieren te bestuderen en waar gewenst en waar mogelijk te verbeteren. Bijzondere aandacht wordt gevraagd voor de methode 'Integrated Population Monitoring' (IPM). De aandacht gaat hierbij uit naar ree, edelhert, wild zwijn en damhert. Er wordt ingegaan op gedragskenmerken die het resultaat van een telling kunnen beinvloeden en op nationaal en internationaal gangbare telmethodieken. Het rapport kan worden gezien als een eerste aanzet voor het ontwikkelen en toepassen van 'state-space models' en 'integrated population models' (IPM) op gegevens van hoefdieren. Dit blijkt in principe mogelijk, ook rekening houdend met sterfte door afschot en verkeer. Het verkrijgen van betere gegevens om de modellen beter te voeden vereist meerjarig ecologisch onderzoek.
Monitoring harbour porpoise abundance and distribution in Dutch waters
Geelhoed, S.C.V. ; Scheidat, M. - \ 2013
Den Burg : IMARES (Report / IMARES Wageningen UR C162/13) - 39
phocoena - zoogdieren - noordzee - monitoring - mammals - north sea
European legislation (Habitats Directive and Marine Strategy Framework Directive) requires monitoring of harbour porpoise (Phocoena phocoena) abundance and distribution, as well as changes thereof, in Dutch North Sea waters. The primary objective of the monitoring in The Netherlands is to report on the status of harbour porpoise in Dutch waters every six years, and determine a trend over 12 years.
Monitoring van gewone en grijze zeehonden in de Nederlandse Waddenzee 2002-2012
Brasseur, S.M.J.M. ; Cremer, J.S.M. ; Dijkman, E.M. ; Verdaat, J.P. - \ 2013
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 352) - 31
zeehonden - zoogdieren - fauna - monitoring - waddenzee - seals - mammals - wadden sea
De jaarlijkse monitoring van de gewone (Phoca vitulina) en de grijze zeehonden (Halichoerus grypus) in de Waddenzee dient ter ondersteuning van het (internationaal) beheer van en het beleid voor de zeehondenpopulaties. Deze tellingen worden sinds 1960 door IMARES uitgevoerd in opdracht van het ministerie van Economische Zaken. In 2012 werden in de Internationale Waddenzee 26,220 dieren geteld(de gehele Waddenzee populatie). Na correctie voor dieren die in het water zouden zijn tijdens de telvluchten wordt de populatie geschat op 38,500 dieren. In Nederland werden rond 6500 volwassen en iets minder dan 1500 pups op de zandplaten geteld. Sinds 2000 worden ook de grijze zeehonden per vliegtuig geteld. Maximaal werden er tijdens de reguliere monitoring in 2012 3059 grijze zeehonden op de ligplaatsen in de Waddenzee geteld. In de geboorteperiode (december 2011) werden 288 pups geteld. Dit is meer dan 75% van alle grijze zeehonden in de Waddenzee
The numbers game in wildlife conservation: changeability and framing of large mammal numbers in Zimbabwe
Gandiwa, E. - \ 2013
University. Promotor(en): Herbert Prins; Cees Leeuwis, co-promotor(en): Ignas Heitkonig. - S.l. : s.n. - ISBN 9789461737465 - 204
wildbescherming - zoogdieren - jachtdieren - populatiedynamica - populatie-ecologie - populatiebiologie - jagen - wild - zimbabwe - wildlife conservation - mammals - game animals - population dynamics - population ecology - population biology - hunting - wildlife

Wildlife conservation in terrestrial ecosystems requires an understanding of processes influencing population sizes. Top-down and bottom-up processes are important in large herbivore population dynamics, with strength of these processes varying spatially and temporally. However, up until recently the role of human-induced top-down and bottom-up controls have received little attention. This is despite the fact that almost all terrestrial ecosystems are influenced by human activities thereby likely altering the natural control of animal populations. Therefore, in this thesis, the role of natural and human-induced controls in influencing large herbivore populations and how human controls (i.e., policy instruments, incentives and provisions) influence human activities and wildlife conservation in a semi-arid African savanna ecosystem are investigated. This study primarily focuses on Gonarezhou National Park (hereafter, Gonarezhou), Zimbabwe and adjacent areas. Zimbabwe experienced an economic crisis and political instability between 2000 and 2008 following the land reforms that started in 2000 which were widely covered in the mass media.

The results indicated a weak synchrony in rainfall and drought occurrence (natural bottom-up process) in areas within the same “climatic” region, and variable responses of large herbivore species to the 1992 severe drought with most large herbivore species’ populations declining following the 1992 drought and increasing thereafter. Therefore, droughts are important in influencing large herbivore populations in semi-arid ecosystems. Furthermore, the results showed variation in the intensity of illegal hunting (top-down human control) which was associated with variation in law enforcement efforts in Gonarezhou. Law enforcement efforts in Gonarezhou were strengthened in 2004 following the employment of additional patrol rangers which resulted in increased park coverage and a decline in recorded illegal activities. Thus, the results show that political instability and economic collapse does not necessarily lead to increased illegal hunting in situations where policy instruments, such as laws, are enforced.

A higher perceived effectiveness of Communal Areas Management Programme for Indigenous Resources (CAMPFIRE - a community-based program that allows local people living in communal areas near protected areas in Zimbabwe to financially benefit from using the wildlife resources within their area) was partly associated with a decline in human-wildlife conflicts. In addition, local communities with higher perceived effectiveness of CAMPFIRE programs partly had more favourable attitudes towards problematic wild animals. Moreover, the results showed that in the 1990s, the majority of newspaper articles highlighted that wildlife conservation in Zimbabwe was largely successful. However, following the land reforms that occurred in 2000, the international media lost interest in wildlife conservation in Zimbabwe, as evidenced by a sharp decline in published articles. Also, the frames changed in the international media with the “political unrest and land reform” blame frame becoming more dominant, and nature conservation was portrayed more negatively. The change in media frames shows that there was a spill-over effect from the political domain into wildlife conservation following Zimbabwe’s land reforms in 2000.

Overall, this study provides new insights on the processes influencing large herbivore population dynamics in human-dominated semi-arid savanna ecosystems which consist of diverse wildlife management regimes and also illuminates the importance of media framing and (mis-)representation of wildlife conservation issues following political instability, crisis or societal unrest. With these findings, it is concluded that natural bottom-up processes (e.g., droughts) influence large herbivore population dynamics whereas policy instruments, incentives, provisions and societal frames mainly have a top-down effect on wild large herbivore populations in savanna ecosystems.

Zoogdiersoorten die geschikt zijn als gezelschapsdier = Mammal species suitable as companion animal
Koene, P. ; Ipema, A.H. ; Mol, R.M. de - \ 2013
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 701) - 86
zoogdieren - dierenwelzijn - diergedrag - diergezondheid - huisvesting, dieren - huisdieren - gezelschapsdieren - dierlijke productie - mammals - animal welfare - animal behaviour - animal health - animal housing - domestic animals - pets - animal production
Are all mammal species suitable to be kept as companion animal? Literature about behaviour, health and welfare of 90 mammal species is analysed and suitability is assessed by scientists and stakeholders. The results is a starting list of suitable species and a method to assess suitability in future.
De amerikaanse nerts in Nederland
Dekker, J.J.A. - \ 2012
Nijmegen : Zoogdiervereniging - ISBN 9789079924318 - 33
pelsdieren - zoogdieren - invasieve exoten - zoögeografie - risicoschatting - nederland - furbearing animals - mammals - invasive species - zoogeography - risk assessment - netherlands
De Amerikaanse nerts Neovison vison is een Noord-Amerikaanse marterachtige die sinds 1920 in Europa als pelsdier wordt gehouden en sinds 1958 in het wild in Nederland voorkomt. Deze studie behandelt de verspreiding, voortplanting, dieet en herkomst van de in het wild levende Amerikaanse nertsen in Nederland. Daarnaast is een korte risicoanalyse voor Nederland gemaakt door raadplegen van literatuur. De nerts komt in Nederland vooral voor rond fokkerijen. De grootste afstand tussen waarnemingslocatie en fokkerij was 45 km. Het aantal in het wild waargenomen dieren is vele malen lager dan de aantallen die als bevrijd gerapporteerd worden.
Enquete positieflijst : leeuw als huisdier?
Livestock Research, - \ 2012
Wageningen : Wageningen UR Livestock Research
dierenwelzijn - leeuwen - huisdieren - gezelschapsdieren - behoeftenbepaling - zoogdieren - huisvesting, dieren - diergedrag - animal welfare - lions - domestic animals - pets - needs assessment - mammals - animal housing - animal behaviour
Leeuwen stellen eisen aan hun omgeving. Zijn leeuwen geschikt als huisdier? Wageningen UR verzamelt in opdracht van het ministerie van EL&I informatie over zoogdieren om te kunnen bepalen of ze gemakkelijk of juist moeilijk als huisdier gehouden kunnen worden. Met die informatie wordt een zogenaamde positieflijst samengesteld. De overheid bepaald mede op basis van die positieflijst welke dieren gehouden mogen worden.
Enquete positieflijst : wrattenzwijn als huisdier?
Livestock Research, - \ 2012
Wageningen : Wageningen UR Livestock Research
dierenwelzijn - huisdieren - gezelschapsdieren - behoeftenbepaling - zoogdieren - huisvesting, dieren - diergedrag - phacochoerus aethiopicus - animal welfare - domestic animals - pets - needs assessment - mammals - animal housing - animal behaviour
Wrattenzwijnen stellen eisen aan hun omgeving. Zijn wrattenzwijnen geschikt als huisdier? Wageningen UR verzamelt in opdracht van het ministerie van EL&I informatie over zoogdieren om te kunnen bepalen of ze gemakkelijk of juist moeilijk als huisdier gehouden kunnen worden. Met die informatie wordt een zogenaamde positieflijst samengesteld. De overheid bepaald mede op basis van die positieflijst welke dieren gehouden mogen worden.
Enquete positieflijst : wallabie als huisdier?
Livestock Research, - \ 2012
Wageningen : Wageningen UR Livestock Research
dierenwelzijn - wallabies - huisdieren - gezelschapsdieren - behoeftenbepaling - zoogdieren - huisvesting, dieren - diergedrag - animal welfare - domestic animals - pets - needs assessment - mammals - animal housing - animal behaviour
Wallabies stellen eisen aan hun omgeving. Zijn wallabies geschikt als huisdier? Wageningen UR verzamelt in opdracht van het ministerie van EL&I informatie over zoogdieren om te kunnen bepalen of ze gemakkelijk of juist moeilijk als huisdier gehouden kunnen worden. Met die informatie wordt een zogenaamde positieflijst samengesteld. De overheid bepaald mede op basis van die positieflijst welke dieren gehouden mogen worden.
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