Maintenance of plant species diversity on dairy farms.

LEI Universiteit LeidenEnvironmental Biology - ol

Graadmeters voor de natuur

Twee jaar geleden publiceerden wij in Landschap een voorstel voor vier graadmeters voor het landelijke natuurbeleid (Ten Brink et al, 2001): de Natuurwaarde, de EHS- doelrealisatie graadmeter, de Soortgroep Trend Index en de Rode Lijst Indicator. Daarop zijn reacties gekomen van Wamelink (2002), Musters et al (2002), Vermaat et al (2003) en - meer zijdelings - Barendregt en Dagevos (2003). We gaan hier in op enkele hoofdpunten van de kritiek

The 2006 national Red list of mammals of the Netherlands and a IUCN Regional Red List.

Conservation Biology - ol

Achtergronddocument Nulmeting Effectindicatoren Monitor Agenda Vitaal Platteland

De Monitor AVP is een systeem waarin eenduidige gegevens worden opgenomen voor monitoring van effecten, resultaten en prestaties van de beleidsdoelstellingen opgenomen in de Agenda Vitaal Platteland (AVP) van het ministerie van Landbouw, Natuur en Voedselkwaliteit (LNV). Dit document geeft de resultaten en achtergrondinformatie van de nulmeting en de methoden van de metingen van de afzonderlijke effectindicatoren van de Monitor AVP. De effectindicatoren zijn bedoeld om de maatschappelijke effecten van de Agenda Vitaal Platteland inzichtelijk te maken. Dit achtergronddocument is opgesteld om de continuïteit voor toekomstige herhalingsmetingen te waarborgen

No evidence of the effect of extreme weather events on annual occurrence of four groups of ectothermic species

Weather extremes may have strong effects on biodiversity, as known from theoretical and modelling studies. Predicted negative effects of increased weather variation are found only for a few species, mostly plants and birds in empirical studies. Therefore, we investigated correlations between weather variability and patterns in occupancy, local colonisations and local extinctions (metapopulation metrics) across four groups of ectotherms: Odonata, Orthoptera, Lepidoptera, and Reptilia. We analysed data of 134 species on a 1×1 km-grid base, collected in the last 20 years from the Netherlands, combining standardised data and opportunistic data. We applied dynamic site-occupancy models and used the results as input for analyses of (i) trends in distribution patterns, (ii) the effect of temperature on colonisation and persistence probability, and (iii) the effect of years with extreme weather on all the three metapopulation metrics. All groups, except butterflies, showed more positive than negative trends in metapopulation metrics. We did not find evidence that the probability of colonisation or persistence increases with temperature nor that extreme weather events are reflected in higher extinction risks. We could not prove that weather extremes have visible and consistent negative effects on ectothermic species in temperate northern hemisphere. These findings do not confirm the general prediction that increased weather variability imperils biodiversity. We conclude that weather extremes might not be ecologically relevant for the majority of species. Populations might be buffered against weather variation (e.g. by habitat heterogeneity), or other factors might be masking the effects (e.g. availability and quality of habitat). Consequently, we postulate that weather extremes have less, or different, impact in real world metapopulations than theory and models suggest

Effects of Natura 2000 on nontarget bird and butterfly species based on citizen science data

ABSTRACT The European Union's Natura 2000 (N2000), is one of the largest international networks of protected areas. One of its aims is to secure the status of a pre-determined set of (targeted) bird and butterfly species. However, also non-target species may benefit from N2000. We evaluated how the terrestrial component of this network relates to the abundance of non-targeted, more common bird and butterfly species using data from long-term volunteer-based monitoring programs in 9,602 sites for birds and 2,001 sites for butterflies. In almost half of the 155 bird species assessed, and particularly among woodland specialists, abundance increased with the proportion of N2000 sites in the landscape. The corresponding positive relationship was found for 27 of the 104 butterfly species, although most of these species were generalists. These positive relationships disappeared for most of the species when land-cover covariates were taken into account, hinting that land-cover is a primary factor defining the positive effects of the N2000 network. The increase in abundance with N2000 was correlated with the specialization index for bird species, but not for butterfly species. Although the N2000 network supports higher abundance of a large spectrum of species, the low number of specialist butterfly species showing a positive association stresses the need to implement management plan improving the quality of habitats of N2000 areas potentially harboring openland butterfly specialists. For a better understanding of the processes involved, we advocate for a standardized collection of data on N2000 sites. Article impact statement: Across Europe the abundance of a majority of nontarget birds and a quarter of nontarget butterflies increased with Natura 2000 coverage. This article is protected by copyright. All rights reservedpeerReviewe