Klantmanagers en hun Logica's

Bij de gemeenten beslissen klantmanagers over de toegang tot uitkeringen, over mogelijke sancties en de deelname aan een re-integratietrajecten. Zij zijn de frontline professionals die binnen hun discretionaire ruimte beslissingen nemen over de uitvoer van de participatiewet. De autonomie van deze professionals wordt begrensd door de logica’s van de markt en de bureaucratie. Hun handelen kan worden geduid vanuit het spanningsveld tussen deze logica’s. Door decentralisaties zijn verantwoordelijkheden voor de re-integratie van bijstandsgerechtigden verplaatst van de rijksoverheid naar gemeenten. Met het opgaan van delen van de Wet Werk en Bijstand en de Wajong in deze Participatiewet verandert de rol van de klantmanager en daarmee ook de opgave van hen om bijstandsgerechtigden aan een betaalde baan te helpen. In de semigestructureerde interviews zijn 14 klantmanagers van een grote gemeente gevraagd te verhalen over hun opvattingen over arbeid, hun positie, bijstandsgerechtigden en hun ervaringen met de participatiewet. De klantmanagers redeneren veelal vanuit een professionele logica en formuleren daarbij nadrukkelijk doelen, die op het welzijn van bijstandsgerechtigden zijn gericht, en die breder liggen dan de toeleiding naar betaald werk. De handelingsruimte wordt begrensd door de participatiewet maar zij geven aan de grenzen ervan zoveel mogelijk op te zoeken wanneer zij dit zinvol achten. Bij het handelen baseren zij zich veelal op individuele ervaringen uit het verleden en ze geven aan horizontale sturing te missen

Het Amsterdamse Experiment rondom de Bijstand

Het Amsterdams Experiment rondom de Bijstand In 2017 voldeed de gemeente Amsterdam niet aan alle voorwaarden van het Ministerie van VWS om aan te sluiten bij het landelijke experiment rondom de bijstand ihkv de Participatiewet. Amsterdam besloot haar eigen experiment op te zetten. Amsterdam telt circa 40.000 bijstandsgerechtigden. Ondanks de aantrekkende arbeidsmarkt wordt deze groep niet kleiner. Amsterdam wil onderzoeken of ze haar huidige beleid kan aanpassen in de hoop dat meer bijstandsgerechtigden –duurzaam- de stap naar (deeltijd) werk durven en kunnen zetten. Het Amsterdam Experiment rond de bijstand is in 2018 gestart en wordt onderzocht door de HvA ism de UvA. De algemene onderzoeksvraag is onder welke condities mensen in de bijstand optimaal kunnen participeren. Doel is inzicht krijgen in de effecten van beleid in termen van financiële (betaald werk) en maatschappelijke (onbetaald werk, welbevinden) participatie. Gedurende vier jaar worden 750 deelnemers geïnterviewd, zodat kan worden gekeken of hun situatie verandert. Afgelopen jaar zijn deelnemers geïnterviewd voor een nulmeting. Op basis van deze nulmeting hebben we een indruk van (a) de mate van het financieel en maatschappelijk participeren van de deelnemers bij aanvang van het experiment en (b) hun opvattingen en attitudes ten aanzien van de bijstand en de instituties waar zij mee te maken hebben. Dit artikel behandelt eerst de start en opzet van het experiment. Vervolgens schetsen we met de nulmeting een aantal kenmerken van de groep bijstandsgerechtigden. Om grip te krijgen op de diversiteit van de onderzoeksgroep maken we gebruik van een clustering van ‘typen’ bijstandsgerechtigden

Biomanipulation in shallow lakes in The Netherlands: an evaluation of 18 case studies

Eighteen shallow lakes in The Netherlands were subjected to biomanipulation, i.e. drastic reduction of the fish stock, for the purpose of lake restoration. The morphology and the nutrient level of the lakes differed, as did the measures applied. In some lakes biomanipulation was accompanied by reduction of the phosphorus loading. In all but two lakes, the Secchi disk transparency increased after the fish removal. Eight lakes (no phosphorus loading reduction, except for one lake) showed a strong and quick response to the measures: the bottom of the lake became visible (`lake bottom view'') and there was a massive development of submerged macrophytes. In eight other lakes the water transparency increased, but lake bottom view was not obtained. In the biomanipulated lakes the decrease in total phosphorus and chlorophyll aand the increase in Secchi disk transparency were significantly stronger than the general trend occurring in Dutch lakes where no measures had been taken. The improvement in the Secchi depth and chlorophyll awas also stronger than in lakes where only the phosphorus load was reduced. The critical factor for obtaining clear water was the extent of the fish reduction in winter. Significant effects were observed only after >75% fish reduction. Success seems to require substantial fish manipulation. In such strongly biomanipulated lakes, wind resuspension of the sediment never prevented the water from becoming clear. No conclusion can be drawn with respect to the possible negative impact of cyanobacteria or Neomysison grazing by Daphniaand consequently on water clarity. In all lakes where there had been a high density of cyanobacteria or years with a high density of Neomysisother factors such as insufficient fishery may explain why lake bottom view was not obtained. In all lakes with additional phosphorus loading reduction the fish stock has been reduced less drastically (15–60%). In these lakes the effects on transparency were less pronounced than in the lakes with > 75% fish removal. Daphniagrazing seems responsible for spring clearing in all clear lakes but one. In three lakes the reduction of benthivorous fish also increased the transparency. The factors that determine water clarity in summer are less obvious. In most clear lakes a low algal biomass coincided with a macrophyte coverage of more than 25% of the lake surface area. However, it was not clear what mechanism caused the low algal biomass in summer, although inorganic nitrogen concentrations were regularly found to be very low. Daphniagrazing in open water seemed to be of little importance for suppressing the algal biomass in summer. Although in most lakes the total phosphorus concentration decreased after the biomanipulation, the dissolved phosphorus concentration remained too high to cause phosphorus limitation of the algal growth. In four out of six clear lakes for which there are long-term data the transparency decreased again after 4 years. In one lake with lower nutrient levels the Secchi disk transparency increased over the years. However, the number of lakes with low nutrient levels is too small for conclusions to be drawn regarding the impact of nutrient levels on the stability of the clear water state

Resilience of alternative stable states during the recovery of shallow lakes from eutrophication: Lake Veluwe as a case study

In this paper we analyze a long-term dataset on the recovery from eutrophication of Lake Veluwe (The Netherlands). Clear hysteresis was observed in a number of ecosystem variables: the route to recovery differed significantly from the route that led to loss of clear water. The macrophyte dominated state disappeared in the late 1960s at TP above 0.20 mg l−1, whereas its return occurred at less than 0.10 mg TP l−1. Several regime shifts resulting in the occurrence of three alternative stable states were observed over a period of 30 years. The turbid state showed resistance to change, despite a strong and prompt reduction in Chl-a following reduction of external P-loading. The most important component that determined hysteresis in the return to clear water was not internal P-loading, but a high level of nonalgal light attenuation (through sediment resuspension) maintained by the interaction between wind and benthivorous fish. Although Chara was able to re-colonize the most shallow parts of the lake, recovery stalled and for a number of years clear (above charophyte beds) and turbid (deeper parts of the lake) water co-existed, as a separate alternative state on route to full recovery. Lake-wide clear water was re-established after bream density had been reduced substantially. This allowed a return of zebra mussels to the lake, whose high filtration capacity helped in maintaining clear water. In this study, we were able to identify the main drivers of hysteresis and regime shifts, although formal demonstration of cause and effect was not possible on the basis of field data alone. We argue that resilience of the present clear water state of Lake Veluwe very much depends on sizable populations of a few keystone species, especially Chara (stoneworts) and Dreissena (zebra mussels), and that careful management of these species is equally important as control of nutrients. Lake management should strive to maintain and strengthen resilience of the ecosystem, and this should offer protection against a renewed collapse of the clear state.

Quantification of allochthonous nutrient input into freshwater bodies by herbivorous waterbirds

1. Waterbirds are considered to import large quantities of nutrients to freshwater bodies but quantification of these loadings remains problematic. We developed two general models to calculate such allochthonous nutrient inputs considering food intake, foraging behaviour and digestive performance of waterbirds feeding in terrestrial habitats: an intake model (IM), mainly based on an allometric relationship for energy requirements and a dropping model (DM), based on allometric relationships for defaecation.2. Reviewed data of nitrogen (N) and phosphorus (P) content of herbivorous food varied according to diet type (foliage, seeds and roots), season and fertilization. For model parameterization average foliage diet contained 38.20 mg N g&minus;1 and 3.21 mg P g&minus;1 (dry weight), whereas mean faeces composition was 45.02 mg N g&minus;1 and 6.18 mg P g&minus;1.3. Daily allochthonous nutrient input increased with body mass ranging from 0.29 g N and 0.03 g P in teals Anas crecca to 5.69 g N and 0.57 g P in mute swans Cygnus olor. Results from IM differed from those of DM from ducks to swans by 63&ndash;108% for N and by &minus;4 to 23% for P. Model uncertainty was lowest for the IM and mainly caused by variation in estimates of food retention time (RT). In DM food RT and dropping mass determined model uncertainty in similar extent.4. Exemplarily applying the models to Dutch wetlands resulted in mean annual contribution of herbivorous waterbirds to allochthonous nutrient loading of 382.8 &plusmn; 167.1 tonnes N a&minus;1and 34.7 &plusmn; 2.3 tonnes P a&minus;1, respectively, which corresponds to annual surface-water loadings of 1.07 kg N ha&minus;1 and 0.10 kg P ha&minus;1.5. There was a distinct seasonal pattern with peak loadings in January, when bird abundances were highest. Lowest inputs were in August, when bird abundance and nutrient content in food was low and birds foraged less in terrestrial habitats. Three-quarters of all nutrient input was contributed by greater white-fronted goose Anser albifrons, greylag goose Anser anser, wigeon Anas penelope and barnacle goose Branta leucopsis alone.6. We provide general, easy to use calculation methods for the estimation of allochthonous nutrient inputs by waterbirds, which are applicable to a range of waterbird species, a variety of potential diets and feeding behaviours, and across spatial scales. Such tools may greatly assist in the planning and execution of management actions for wetland nutrient budgets.<br /

The impact of climate change on lakes in the Netherlands: a review

Climate change will alter freshwater ecosystems but specific effects will vary among regions and the type of water body. Here, we give an integrative review of the observed and predicted impacts of climate change on shallow lakes in the Netherlands and put these impacts in an international perspective. Most of these lakes are man-made and have preset water levels and poorly developed littoral zones. Relevant climatic factors for these ecosystems are temperature, ice-cover and wind. Secondary factors affected by climate include nutrient loading, residence time and water levels. We reviewed the relevant literature in order to assess the impact of climate change on these lakes. We focussed on six management objectives as bioindicators for the functioning of these ecosystems: target species, nuisance species, invading species, transparency, carrying capacity and biodiversity. We conclude that climate change will likely (i) reduce the numbers of several target species of birds; (ii) favour and stabilize cyanobacterial dominance in phytoplankton communities; (iii) cause more serious incidents of botulism among waterfowl and enhance the spreading of mosquito borne diseases; (iv) benefit invaders originating from the Ponto-Caspian region; (v) stabilize turbid, phytoplankton-dominated systems, thus counteracting restoration measures; (vi) destabilize macrophyte-dominated clear-water lakes; (vii) increase the carrying capacity of primary producers, especially phytoplankton, thus mimicking eutrophication; (viii) affect higher trophic levels as a result of enhanced primary production; (ix) have a negative impact on biodiversity which is linked to the clear water state; (x) affect biodiversity by changing the disturbance regime. Water managers can counteract these developments by reduction of nutrient loading, development of the littoral zone, compartmentalization of lakes and fisheries management