Kleinbloemige salie (Salvia verbenaca L.) terug in Nederland

In the past Salvia verbenaca occurred as a native, albeit very rare plant in two parts of the Netherlands, viz. the southwestern province of Zeeland and the riverine area in the eastern province of Gelderland. Because it was not recorded anymore after 1948, it was considered extinct. Excluding the 1989 man-made locality in the north, it was rediscovered in 2000 on a dike along the Wester Scheldt, probably on the same spot where it was erroneously identified as Salvia pratensis in 1981. Also in the past such mistakes occurred for other localities in Zeeland

Das Rubetum taxandriae ass. nov. (Lonicero-Rubion silvatici, Lonicero-Rubetea plicati) : eine neue Brombeer-Assoziation im Gebiet der belgischen und niederländischen "Kempen"

Bramble scrubs are among the least known and understood vegetation types in Europe. In the Dutch National Vegetation Overview, three associations belonging to the Lonicero-Rubion silvatici were distinguished, viz. the Rubetum grati, Rubetum silvatici, and Rubetum pedemontani. During several vegetation mapping projects and Rubus excursions, a distinct type of bramble scrub was recorded repeatedly in the Campine in the province Noord-Brabant in the southern part of the Netherlands. In this paper, this scrub is described as a new association, the Rubetum taxandriae Haveman, de Ronde & Weeda, with R. taxandriae, R. campaniensis, and R. baronicus as character species, and R. insectifolius as regional character species. Variation, ecology and distribution of this new association are given and discussed, and two subassociations are distinguished. The differences with the Rubetum silvatici, to which this community was believed to belong, are discussed. Based on an earlier analysis of the centres of diversity of the genus Rubus in the Netherlands, it is supposed that the Rubetum silvatici in its circumscription in the Dutch National Vegetation Overview can be divided in more regionally distributed communities, partly as subassociations of the Rubetum silvatici, partly as independent associations.Brombeergebüsche gehören zu den am wenigsten bekannten Vegetationstypen in Europa. Bisher wurden drei Assoziationen für die Niederlande beschrieben: Rubetum grati, Rubetum silvatici und Rubetum pedemontani. Bei verschiedenen Kartierungsarbeiten und Exkursionen wurde in "De Kempen" in der Provinz Noord-Brabant im südlichen Teil der Niederlande mehrmals ein abweichendes Gebüsch beobachtet. Dieses Gebüsch wird hier als neue Assoziation: Rubetum taxandriae Haveman, de Ronde & Weeda beschrieben, mit R. taxandriae, R. campaniensis und R. baronicus als Kennarten und R. insectifolius als regionaler Kennart. Artenverbindung, Ökologie und Verbreitung werden erörtert, und zwei Subassoziationen werden beschrieben. Der Unterschied zum Rubetum silvatici wird diskutiert. Aufgrund einer früher publizierten Analyse von Diverzitätszentren der Gattung Rubus in den Niederlanden wird angenommen, dass das Rubetum silvatici dort in mehrere regional verbreitete Gebüschtypen aufgespalten werden kann, teilweise als Subassoziationen, teilweise vielleicht besser als eigene Assoziation

Habitat and management preference of Bromus racemosus L., a rare species in mesic meadows of Northwest Europe

Bromus racemosus L. is a rather rare grass species of moist meadows. It has strongly decreased in the course of the 20th century due to intensification of agricultural grassland management, and is therefore included in Red Lists of several European countries. Its winter annual life-cycle is remarkable for a species of permanent grasslands. The aim of this study is to determine the habitat preference and optimal management of B. racemosus in the Netherlands and surrounding countries. Vegetation, soil and hydrological data from 28 sites in the Netherlands have been compared with B. racemosus cover, and with vegetation data from surrounding countries. The results indicate that B. racemosus is characteristic of Molinio- Arrhenatheretea meadows with good mineralisation and aftermath grazing. The optimum lies in grasslands of the alliance Alopecurion pratensis (Deschampsion cespitosae), but the species ranges from wetter Calthion palustris meadows to drier Arrhenatherion elatioris and Cynosurion cristati grasslands. It prefers intermediate nutrient levels and hydrological conditions (mesic sites), but within this range the highest cover is found in relatively nutrient rich and dry sites. Because of the absence of a seedbank and a low dispersal capability, B. racemosus is vulnerable to changes in grassland management. A management of mowing after 15 June and aftermath grazing is most suitable, since it enables fruit ripening and the maintenance of an open sward, needed for germination and development. The risk of extinction is likely to be higher in flat polders than in floodplain sites with natural relief, where the species may shift between belts in different years.</p

Habitat- und Managementpräferenz von Bromus racemosus L., einer seltenen Art in mäßig nährstoffreichen Feuchtwiesen Nordwesteuropas

Bromus racemosus L. is a rather rare grass species of moist meadows. It has strongly decreased in the course of the 20th century due to intensification of agricultural grassland management, and is therefore included in Red Lists of several European countries. Its winter annual life-cycle is remarkable for a species of permanent grasslands. The aim of this study is to determine the habitat preference and optimal management of B. racemosus in the Netherlands and surrounding countries. Vegetation, soil and hydrological data from 28 sites in the Netherlands have been compared with B. racemosus cover, and with vegetation data from surrounding countries. The results indicate that B. racemosus is characteristic of Molinio-Arrhenatheretea meadows with good mineralisation and aftermath grazing. The optimum lies in grasslands of the alliance Alopecurion pratensis (Deschampsion cespitosae), but the species ranges from wetter Calthion palustris meadows to drier Arrhenatherion elatioris and Cynosurion cristati grasslands. It prefers intermediate nutrient levels and hydrological conditions (mesic sites), but within this range the highest cover is found in relatively nutrient rich and dry sites. Because of the absence of a seedbank and a low dispersal capability, B. racemosus is vulnerable to changes in grassland management. A management of mowing after 15 June and aftermath grazing is most suitable, since it enables fruit ripening and the maintenance of an open sward, needed for germination and development. The risk of extinction is likely to be higher in flat polders than in floodplain sites with natural relief, where the species may shift between belts in different years.Bromus racemosus L. ist eine ziemlich seltene Grasart der Feuchtwiesen. In den Niederlanden wird sie in zwei Unterarten unterteilt, subsp. racemosus und subsp. commutatus, die in anderen Ländern meist als separate Arten aufgefasst werden (SPALTON 2002). Die vorliegende Arbeit befasst sich hauptsächlich mit B. racemosus s.str. (= B. racemosus subsp. racemosus). Bromus racemosus gehört innerhalb der Gattung zu Bromus s.str., mit einjährigen, auf anthropogene Standorte beschränkte Arten (Anökophyten). Das Areal von B. racemosus umfasst weite Teile Europas. In vielen Ländern steht sie auf der Roten Liste, weil sie aufgrund der Intensivierung der Landwirtschaft in den letzten Jahrzehnten in starkem Rückgang begriffen ist. Ihr winterannueller Lebenszyklus ist bemerkenswert für eine Sippe des Dauergrünlands. Die Samen keimen sofort nach der Reifung, sobald sie feucht werden. Dies verhindert die Bildung einer Samenbank (LUTZ 1996, JENSEN 2004). Die vorliegende Studie soll das Wissen über die Habitat- und Managementpräferenz von B. racemosus in den Niederlanden und den benachbarten Gebieten vergrößern. Dazu wurden der Einfluss von abiotischen Bedingungen und der Grünlandbewirtschaftung auf ihre Abundanz und ihre syntaxonomische Position untersucht

Riempjes (Corrigiola litoralis L.) terug in het rivierengebied

Until the mid-20th century, Corrigiola litoralis was recorded from river banks in several parts of the Dutch riverine area where it mainly occurred along the River Meuse and the River Waal. For a few decades, the species appeared to have become extinct in this habitat due to river canalisation and intensive agriculture, but in recent years it has been found again on river sides. In 1999, a single specimen was observed on a gravel bank along the River Meuse. In the Nijmegen region, the species seems to have reclaimed its former area along the River Waal. After the re-emergence of active sandy levees due to nature rehabilitation projects and several flood events, the species has become gradually more numerous there since 1996. Hitherto, Corrigiola litoralis has occupied four floodplains in the Nijmegen region. The species shows a preference for sandy to gravely deposits located near the river which are subject to strong morphological dynamics due to erosion and sedimentation by water currents. The sites are open and fully exposed. The moisture content of the substrate varies from moist to very dry in summer. A further increase of the species along the River Waal and River Meuse (Grensmaas) is expected due to habitat improvement resulting from nature development projects. Possibly, the species will also profit from the ongoing climate change

Naamlijst en verspreidingsgegevens van de Nederlandse bramen (Rubus L. subgenus Rubus)

In Noordwest-Europa is de taxonomie van bramen (Rubus L. subgenus Rubus) goed op orde en de verspreiding van bramen in de verschillende landen goed bekend dankzij herbarium- en veldonderzoek vanaf de jaren 1970. De meeste soorten zijn gestabileerde apomicten die zonder bevruchting zaad vormen. De nakomelingen van een zich apomictisch voortplantende braam zijn hierdoor genetisch gelijk aan de moederplant. In Nederland dateert onderzoek aan bramen pas van na 1900 met een actieve periode na de Tweede Wereldoorlog. Dit resulteerde in 1956 in de Rubi Neerlandici door W. Beijerinck, een overzicht gebaseerd op de kunstmatig soortsopvatting van H. Sudre (Rubi Europae; 1908–1913). Het moderne, op typemateriaal en veldwerk gebaseerde onderzoek startte begin jaren 1970 en resulteerde in de decennia erna tot de herkenning en beschrijving van tal van nieuwe regionale soorten en nieuwe namen voor verkeerd geïnterpreteerde soorten. Door de meeste Europese bramendeskundigen wordt een soortsopvatting gehanteerd die inhoudt dat taxa met een areaaldiameter kleiner dan 50 km niet worden beschreven als soort. Deze opvatting wordt ook door ons gehanteerd. Op de naamlijst van Nederlandse bramen van het subgenus Rubus staan 191 soorten verdeeld over 4 secties: Rubus (Zwarte braam; ‘Rubus fruticosus agg.’; 147 soorten), Corylifolii Lindl. (Wasbraam; ‘Rubus corylifolius agg.’; 34 soorten), Caesii Lej. & Courtois (Dauwbraam; 2 soorten) en Subidaei (Focke) A.Beek (Purperbraam; 8 soorten). De laatste sectie omvat gestabiliseerde soorten met R. idaeus L. (Framboos) als voorouder. Nomenclatorische aspecten van de Nederlandse taxa en de beschrijving van enkele nieuwe wasbramen zijn in begeleidende artikelen ondergebracht. Alle taxa – secties, subsecties, series en soorten – zijn voorzien van Nederlandse namen. Aangezien areaalgrootte een belangrijke rol speelt in de taxonomie, is elke soort toegekend aan een areaalcategorie: W1 (zeer wijdverbreid; areaaldiameter >1500 km), W2 (wijdverbreid; idem 500–1500 km), R1 (bovenregionaal; idem 250–500 km) of R2 (regionaal; idem 50–250 km). Van de Nederlandse bramen hebben 97 soorten (51%) een regionale verspreiding; slechts 32 soorten (17%) zijn zeer wijdverbreid. Alle digitaal beschikbare verspreidingsgegevens van soorten uit het subgenus Rubus (excl. R. caesius L.) zijn samengebracht in een database, in totaal ruim 43.000 records waarvan 37.000 met een nauwkeurigheid op km-hokniveau of beter. Van alle soorten (excl. Rubus caesius) is de landelijke zeldzaamheid bepaald op grond van Rode Lijst-criteria. Bijna 80 soorten zijn landelijk zeer zeldzaam, 60 zeldzaam, 25 vrij zeldzaam en ongeveer 20 vrij algemeen of algemeen. Zeer algemene soorten ontbreken, wat niet alleen heeft te maken met het hoge aandeel regionale soorten, maar ook met het feit dat in de klei- en veengebieden zeer weinig bramen voorkomen. De regionale verspreiding wordt per soort gegeven als percentage van het aantal uurhokken per floradistrict. Hotspots van soortenrijkdom met meer dan 40 soorten per uurhok liggen in oude boslandschappen in het Rijk van Nijmegen, de Liemers, de Oude IJsselstreek en aangrenzende Veluwezoom en de omgeving van Winterswijk (Achterhoek), Epen-Vijlen (Zuid Limburg) en Oldenzaal (Twente). De regionale soorten dragen sterk bij aan de identiteit van de regio’s. De relatief grote landelijke soortenrijkdom met regionale hotspots onderstreept de ligging van ons land in het centrum van de (sub)atlantische bramendiversiteit in Europa. The taxonomy and distribution of brambles (Rubus L. subgenus Rubus) are well-known in northwestern Europe due to herbarium studies and extensive field work from the 1970s onwards. Most brambles are stabilized apomictic species that form fruits without prior fertilization. Therefore, offspring is genetically identical with the mother plant. In the Netherlands, the study of brambles did not start until 1900, with a relatively active period occuring after World War II. This resulted in the publication of Rubi Neerlandici by W. Beijerinck in 1956, an overview based on the artificial species circumscription of H. Sudre (Rubi Europae; 1908–1913). Modern research, based on the study of type material supplemented with field work began in the 1970s and lead to the recognition of several newly described regional species as well as new names for misapplied species. Most bramble experts in Europe agree on a species circumscription that includes a geographic constraint: taxa with a range less than 50 km in diameter are not described as species. We adhere to this view as well. The Dutch checklist of subgenus Rubus comprises 191 species in 4 sections: Rubus (‘Rubus fruticosus agg.’; 147 species), Corylifolii Lindl. (‘Rubus corylifolius agg.’; 34 species), Caesii Lej. & Courtois (2 species) and Subidaei (Focke) A.Beek (8 species). The latter section includes stabilized species with Rubus idaeus L. as an ancestor. Nomenclatural aspects of the Dutch taxa and the description of some new Corylifolii taxa are dealt with in accompanying papers. All taxa on the checklist are provided with Dutch names, including sections, subsections and series. Since range size is taxonomically important, this feature has been classified and assigned to each species as W1 (very widespread; range diameter >1500 km), W2 (widespread; 500–1500 km), R1 (supraregional; 250–500 km) or R2 (regional; 50–250 km). The Dutch checklist contains 97 regional species (51%); only 32 species (17%) are very widespread. All digitally available distribution data for species of Rubus subgenus Rubus (excluding Rubus caesius L.) have been merged into a database, currently comprising about 43,000 records, including 37,000 with an accuracy of one kilometer or better. National rarity of species (Rubus caesius excluded) has been coded according to Dutch Red List criteria based on the number of occupied 5×5 km-squares. Almost 80 species are nationally very rare, 60 rare, 25 rather rare and about 20 rather common or common. Very common species are absent from the section Rubus, which is not only caused by the large proportion of regional species, but also by the low frequency of brambles on clay and peat soils in the western and northern parts of the country. Regional occurrence is expressed as percentage occupied relative to the total number of 5×5 km-squares for each flora district. Hotspots of species richness with more than 40 species per 5×5 km-square occur in old woodland landscapes in physiogeographic gradients with sandy and loamy soils. The national species richness in a European context, the high numbers of regional species, and the occurrence of hotspots of bramble diversity emphasize the central position of the Netherlands within the (sub) atlantic range of brambles in Europe