Werken bij het NIOO

Voor dit project zoeken we  een aantal studenten (MBO/HBO/MSc allemaal mogelijk) om mee te draaien in de veldcampagne en bodemmonsters te verzamelen door heel het land.

Where biodiversity loss has on average been halted in nature reserves, biodiversity of rural areas keeps declining. The larger aim of this project (Living Lab B7) is to enhance biodiversity in the rural part of The Flower Bulb Region.

Where biodiversity loss has on average been halted in nature reserves, biodiversity of rural areas keeps declining. The larger aim of this project (Living Lab B7) is to enhance biodiversity in the rural part of The Flower Bulb Region.

Where biodiversity loss has on average been halted in nature reserves, biodiversity of rural areas keeps declining. The larger aim of this project (project Living Lab B7) is to enhance biodiversity in the rural part of The Flower Bulb Region.

Suitable for Master students for at least six months

Suitable for Master students for at least six months

Rapid evolutionary adaptation is increasingly considered as an important mechanism allowing animals to adapt to a rapidly changing world. Our research has shown that rotifers, a type of very common freshwater zooplankton, are able to adapt to poor food quality or enhanced salt concentrations in not more than a few months. At this moment, we investigate how rotifers cope with combinations of stressors. More specifically, we run evolution experiments in the laboratory exposing populations to the metal Cu and high temperatures, with the aim to study how adaptation to one stressor impedes or enhances the response to the other stressor.

Woodland expansion in arid environments occurs episodically during wet years. Recent research indicates that tree seedling growth rate and survival is crucial to explain the differences across ecosystems and that soil microorganisms likely play a crucial role.

Hyperparasitoids are insects that develop on, or in another parasitoid species. Secondary hyperparasitoids attack primary parasitoid hosts (usually their cocoons) that have already emerged from the secondary herbivore host. In spite of their potential importance in affecting the dynamics of plant-herbivore-parasitoid systems (over three trophic levels), little is still known about the biology and life-history of secondary hyperparasitoids (in the fourth trophic level).

Parasitoid wasps are known to exhibit two strategies for exploiting host resources during development. The first is for the parasitoid larvae to consume the entire host (such as a caterpillar) before pupation. However, some parasitoids consume only a small fraction of the host during development. In this case, the mature parasitoid larvae emerge through the sides of the still-living host and pupate on, or next to it. In some instances, the caterpillar may remain alive for up to two weeks after parasitoid pupation and remain very close to the parasitoid cocoons.

Evidence is accumulating that epigenetic mechanisms can affect heritable phenotypic traits and thus, may play a role in plant adaptation. However, little is known about the magnitude and relevance of functional epi-allelic variation in natural plant populations.

Host-plant suitability and quality for herbivore (and possibly natural enemy) development is determined by the presence of sufficient levels of nutrients and concentrations of adverse metabolites such as specific secondary plant compounds and digestibility reducers. In nature, these characteristics are dynamic and can change within individual plants over the course of a growing season. Many species of multivoltine insects (insects have more than one generation per year) are known to attack short-lived annual plants i.e. plants that are present for only 1or 2 months in the field. These short-lived plants may germinate and grow at different times and/or locations during the growing season. In this situation, each herbivore generation is faced with the challenge of leaving the natal patch to find and lay eggs on a different plant species that may be growing some distance from where they themselves developed. At the same time, the quality of the different food plant species on which they feed and grow over the spring and summer seasons may also be highly variable.

Pathogens can be categorised as bacteria, viruses, protozoa and helminths (Awuah, 2006). The most common pathogen found in wastewater is Salmonella. However, there are many other pathogens harmful to human health, such as E. coli, Pseudomonas, Shigella, Vibrio, Mycobacterium, Clostridium, Leptospira, Yersinia, Giardia, Cryptosporidium, intestinal worms, Norwalk virus and rotavirus (Marsalek et al., 2002).

Before the advent of molecular genetic techniques, zooplankton taxa were believed to be not exceedingly rich in species. Many species were also assumed to have a wide biogeographic distribution pattern. Recently, however, it has become more and more obvious that cryptic species (i.e. species that can not be morphologically distinguished) are actually rather common and that earlier biodiversity assessments have largely underestimated the number of species. This opens a lot of interesting avenues for evolutionary and ecological research, with questions such as: How long ago have these species come to existence? Did they evolve in sympatry or allopatry? Is there still hybridization going on? And to what extend do such species (and possibly their hybrids) differ from each other ecologically?

Als planten worden aangevallen door bovengrondse insecten, worden bij een aantal plantensoorten stoffen vrijgemaakt die de parasitoiden van de insecten aantrekken. Er is vrijwel niets bekend of eenzelfde soort fenomeen (aantrekking van antagonisten als reactie op wortelaantasting door nematoden, insecten, of schimmels) zich ook in de bodem voordoet. Het is ook niet bekend of de inductie van een reactie van een plant op een insect bovengronds een effect heeft op een wortelherbivoor (nematode, insect).

Light pollution is increasingly recognised as one of the strongest anthropogenic factors that can impact ecosystems. At the NIOO-KNAW, we investigate the impact of light on nocturnal species, such as bats, amphibians, mice and mustelids. We try to understand their response to the colour composition of light, and the ligth intensity

Om voedselwebben te onderzoeken, worden twee benaderingen naast elkaar toegepast: computermodellen en modelecosystemen (voedselwebjes). De belangrijkste experimentele ecosystemen die gebruikt worden zijn zogenaamde chemostaten: vaten van 1,6 liter waarin het plankton zich bevindt en die een continue aanvoer van verse voedingsstoffen hebben. Verder hebben we ook de beschikking over de Limnotrons (zie afbeelding), van zo'n 1000 liter, die meer worden gebruikt om grootschaliger processen te betuderen. Tijdens experimenten worden regelmatig monsters genomen uit beide typen modelecosytemen om veranderingen te volgen in de planktongemeenschap (bijv. aantallen, mate van verdediging) en abiotische variabelen (bijv. pH of nutriënten).

Een groot deel van de potentiële reproductie van planten in natuurlijke populaties gaat verloren door toedoen van pathogenen en herbivoren. Twee anjerachtigen, Silene alba en S. dioica worden in ons land bijvoorbeeld geïnfecteerd door de brandschimmel Ustilago violacea, die de vruchtbeginsels van geïnfecteerde bloemen aborteert, en de helmhokjes gebruikt om haar eigen sporen in te produceren.

Secundaire plantenstoffen kunnen een rol spelen bij afweer tegen zowel herbivoren als fytopathogene schimmels. In natuurlijke populaties wordt vaak een grote mate van genetische variatie in (constitutieve) gehaltes aan secundaire plantenstoffen gevonden. Een algemeen aanvaarde verklaring hiervoor is dat er kosten verbonden zijn aan deze vorm van afweer: waardgenotypen met hoge gehaltes hebben een selectief voordeel bij hoge selectiedruk door herbivoren, maar genotypen met lage gehaltes, d.w.z. lage kosten, bij een lage selectiedruk.

A study on the effects of stoichiometric constraints on rotifer populations