9 results on '"Van der Kolk, Henk"'
Search Results
2. GPS tracking data of Eurasian oystercatchers (Haematopus ostralegus) from the Netherlands and Belgium.
- Author
-
van der Kolk, Henk-Jan, Desmet, Peter, Oosterbeek, Kees, Allen, Andrew M., Baptist, Martin J., Bom, Roeland A., Davidson, Sarah C., de Jong, Jan, de Kroon, Hans, Dijkstra, Bert, Dillerop, Rinus, Dokter, Adriaan M., Frauendorf, Magali, Milotić, Tanja, Rakhimberdiev, Eldar, Shamoun-Baranes, Judy, Spanoghe, Geert, van de Pol, Martijn, Van Ryckegem, Gunther, and Vanoverbeke, Joost
- Subjects
- *
WINTER , *ACCELERATION measurements , *INFORMATION storage & retrieval systems , *ANIMAL mechanics , *BIODIVERSITY , *HABITATS - Abstract
We describe six datasets that contain GPS and accelerometer data of 202 Eurasian oystercatchers (Haematopus ostralegus) spanning the period 2008–2021. Birds were equipped with GPS trackers in breeding and wintering areas in the Netherlands and Belgium. We used GPS trackers from the University of Amsterdam Bird Tracking System (UvA-BiTS) for several study purposes, including the study of space use during the breeding season, habitat use and foraging behaviour in the winter season, and impacts of human disturbance. To enable broader usage, all data have now been made open access. Combined, the datasets contain 6.0 million GPS positions, 164 million acceleration measurements and 7.0 million classified behaviour events (i.e., flying, walking, foraging, preening, and inactive). The datasets are deposited on the research repository Zenodo, but are also accessible on Movebank and as down-sampled occurrence datasets on the Global Biodiversity Information Facility (GBIF) and Ocean Biodiversity Information System (OBIS). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. A new Psammina species with exceptionally long conidial arms, with a key to the ten known species of the genus.
- Author
-
van der Kolk, Henk-Jan, Earland-Bennett, Peter M., and Hawksworth, David L.
- Subjects
- *
SPECIES , *ARM , *DNA , *SYNONYMS , *LICHENS - Abstract
The algicolous and lichenicolous species Psammina filamentosa is described from the Netherlands and the UK, and is characterized by long (generally over 50 μm) and somewhat tapered conidial arms. Psammina filamentosa is compared with other Psammina specimens found in the same habitat, growing on algae or lichens on the dry side of trees and stones. Psammina filamentosa, P. inflata and P. stipitata differ in the dimensions of their conidial arms. Psammina simplex, however, may be a synonym of P. stipitata, and a DNA study is needed to determine whether it is a distinct species or developing material of P. stipitata. Psammina inflata is also reported as new for the Netherlands. A new worldwide key to the 10 species of Psammina currently known is provided, including three species described from plant material. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Using a phenological network to assess weather influences on first appearance of butterflies in the Netherlands.
- Author
-
van der Kolk, Henk-Jan, WallisDeVries, Michiel F., and van Vliet, Arnold J.H.
- Subjects
- *
PHENOLOGY , *BUTTERFLIES , *HOST plants , *EFFECT of temperature on animals , *FOOD chains - Abstract
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. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
5. Electoral System Change In The Netherlands: The Road From PR To PR.
- Author
-
Van der Kolk, Henk
- Subjects
- *
ELECTIONS , *REPRESENTATIVE government , *COMPULSORY voting , *PRACTICAL politics , *DECISION making - Abstract
Using the model of Benoit (2004) we describe and explain the change and persistence of the Dutch electoral system between 1897 and 2005. We focus on the introduction of proportional representation in 1917, the attempts to further increase the threshold between 1950 and 1980, the abolishment of compulsory voting in 1970, the attempt to introduce a district system with large multi-member districts in 1970, and finally the attempt in 2005 to introduce a mixed system with multi-member districts. We systematically use ex ante perceived consequences of an alternative electoral system with regard to changes in the distribution of seats to understand the preferences of political parties with regard this alternative system. We will show that many (stated) preferences of political parties with regard to electoral systems change can indeed be understood once we assume parties to be seat-maximizers. Some preferences, however, cannot be explained by this assumption. In addition many potential changes in the Dutch electoral law appear to have no consequences for the distribution of seats at all. This means the model of Benoit is unable to explain or predict a large set of potential changes in an electoral system. In addition we shall show that electoral law change and other policy areas and tightly connected. This makes preferences with regard to electoral systems and the decision-making procedures only part of an explanation of decision-making about electoral systems. Electoral systems are simply part of politics and therefore less predictable than is assumed by Benoit. ..PAT.-Conference Proceeding [ABSTRACT FROM AUTHOR]
- Published
- 2005
6. Problems and participation: an explanation of citizen-initiated contacts using a problem-oriented approach.
- Author
-
Van der Kolk, Henk and Lelieveldt, Herman
- Subjects
- *
SOCIAL status , *MASS mobilization , *PARTICIPATION , *NEIGHBORHOODS , *SOCIAL groups - Abstract
Research on the relationship between socioeconomic status (SES) and the mobilization of political and administrative officials through ?citizen-initiated contacts? (or ?particularized contacts?), has produced conflicting results. Some have found a positive relationship between these two variables, others have found a negative, parabolic or a negligible relationship. A number of conceptual and methodological problems may have contributed to these conflicting results. In this study, we examine the effects of SES and other individual level characteristics on citizen-initiated contacting in a way that avoids many of these problems. It does so by focusing on the mobilization of officials by individual citizens in response to various neighborhood problems using a ?problem-oriented approach? to the study of participation. The analysis is restricted to individuals who perceive a particular neighborhood situation as problematic: which problems do and which problems don?t result in citizen initiated contacts? Characteristics of the perceived problem, of the individual perceiving the problem and of the neighborhood in which the individual lives are taken as predictors. The data are collected in a large face-to-face survey among citizens in a medium sized city in the Netherlands. In this survey 557 citizens from different neighborhoods were interviewed mentioning 1516 problems ranging from heavy traffic to noisy neighbors. The data are analyzed using multi-level analysis since perceived problems are nested within individuals. According to the data, it is the type of problem (individual instead of collective) and the social involvement of those perceiving the problem, that determine whether a problem leads to an action or not. The other characteristics of individuals do not contribute significantly to the explanation of action. While at first sight it seems that biases in problem conversion do not exist if one uses this problem-oriented approach, we subsequently show that many individual level variables do have a significant impact on the number of problems residents experience, which gives us a more precise understanding of the problem-participation nexus than the conventional action-oriented approach. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
7. ELECTORAL SYSTEM CHANGE IN THE NETHERLANDS: THE ROAD FROM PR TO PR (1917-2006).
- Author
-
van der Kolk, Henk
- Subjects
- *
ELECTIONS , *ELECTION monitoring , *ELECTORAL coalitions , *PRACTICAL politics , *VOTING & society , *DUTCH people - Abstract
The article summarizes significant changes and failure attempts to change the electoral system of The Netherlands since 1917. Outlines of related models depicting electoral change and stability as well as the rational choice being the current dominant theory were discussed. It also explains the change and persistence of the Dutch electoral system between 1917 and 2005, the failure attempts to increase the threshold between 1950 to 1980, and the abolition of compulsory voting in 1970.
- Published
- 2007
- Full Text
- View/download PDF
8. Colour-ring wear and loss effects in citizen science mark-resighting studies.
- Author
-
Allen, Andrew M., Ens, Bruno J., van de Pol, Martijn, van der Jeugd, Henk, Frauendorf, Magali, van der Kolk, Henk-Jan, Oosterbeek, Kees, Nienhuis, Jeroen, and Jongejans, Eelke
- Subjects
CITIZEN science ,SCIENTISTS ,BIRD migration ,REMANUFACTURING ,ACQUISITION of data ,PROBABILITY theory - Abstract
Background: Ring wear and loss may have important consequences for mark-recapture studies that aim to estimate survival trends. Our study quantifies the rates of wear and loss from a long-running colour-ringing project of the Eurasian Oystercatcher (Haematopus ostralegus) in the Netherlands. Methods: Our analysis included 8909 colour-ringed oystercatchers with 118,071 resightings, predominantly ringed and observed by citizen scientists. We quantified how ring wear and loss may vary with ring colour and age, and how this may impact resighting probabilities. We then determined how ring loss may impact survival estimates and resighting probabilities of mark-recapture models by simulating four scenarios of how citizen scientists may resight and report birds with lost colour rings. Results: Annual rates of colour ring loss averaged 2.5% compared with 1% for ring wear, but lost rings also had a higher reporting probability (31.2%) than worn rings (10.3%). Lost rings may not directly impact survival estimates since 50% of oystercatchers with lost rings could still be uniquely identified. Ring wear and loss rapidly increased between 10 and 15 years after ringing. Rates of ring loss were comparable amongst ring colours, but the wear rate appeared higher for red and white rings compared to other colours. Rates of ring wear and loss varied significantly amongst different regions in our study, which were characterised as having different habitat features. Differential rates of ring wear may have important implications for studies conducted over large geographical scales or of multiple species. Conclusions: Based on simulations of ring loss in our population, estimates of apparent survival may be 0.3–1.2% lower whilst the impact of ring wear was deemed even lower. We developed a table of recommendations containing advice for ring fitting, data collection, study design, and mark-recapture analyses, so that future colour-ringing studies can benefit from our experiences in collecting and analysing data of ring wear and loss through citizen science. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
9. Connecting foraging and roosting areas reveals how food stocks explain shorebird numbers.
- Author
-
Bakker, Wiene, Ens, Bruno J., Dokter, Adriaan, van der Kolk, Henk-Jan, Rappoldt, Kees, van de Pol, Martijn, Troost, Karin, van der Veer, Henk W., Bijleveld, Allert I., van der Meer, Jaap, Oosterbeek, Kees, Jongejans, Eelke, and Allen, Andrew M.
- Subjects
- *
TIDAL basins , *ROOSTING , *SHORE birds , *BIOINDICATORS , *ECOSYSTEM health , *SHELLFISH - Abstract
Shorebird populations, especially those feeding on shellfish, have strongly declined in recent decades and identifying the drivers of these declines is important for conservation. Changing food stocks are thought to be a key driver of these declines and may also explain why trends have not been uniform across Europe's largest estuary. We therefore investigated how winter population trends of Eurasian oystercatchers (Haematopus ostralegus) were linked to food availability in the Dutch Wadden Sea. Our analysis incorporated two spatial scales, a smaller scale focused on roost counting areas and food available to birds in these areas and a larger spatial scale of tidal basins. A novelty in our study is that we quantify the connectivity between roosting and foraging areas, identified from GPS tracking data. This allowed us to estimate food available to roosting birds and thus how food availability may explain local population trends. At the smaller spatial scale of roost counting areas, there was no clear relationship between available food and the number of roosting oystercatchers, indicating that other factors may drive population fluctuations at finer spatial scales. At the scale of tidal basins, however, there was a significant relationship between population trends and available food, especially cockle Cerastoderma edule ,. Mortality and recruitment alone could not account for the large fluctuations in bird counts, suggesting that the site choice of wintering migratory oystercatchers may primarily drive these large fluctuations. Furthermore, the relationship between oystercatcher abundance and benthic food stocks, suggests winter shorebird counts could act as ecological indicators of ecosystem health, informing about the winter status of food stocks at a spatial scale of tidal basins. • Understanding the link between predators and prey is important for conservation. • We estimated available prey biomass in foraging areas of GPS-tracked shorebirds. • We relate available prey biomass to population trends at shorebird roosting areas. • A significant positive relationship was found at the scale of tidal basins. • Estimating benthic prey biomass in foraging areas may assist population assessments. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.