Biomedical subjects

Frank Berendse

Publications and source records attributed to Frank Berendse.

4 recordsLinked to original sources

PubMed2006

The interplay between shifts in biomass allocation and costs of reproduction in four grassland perennials under simulated successional change.

When perennial herbs face the risk of being outcompeted in the course of succession, they are hypothesized to either increase their biomass allocation to flowers and seeds or to invest more in vegetative growth. We tested these hypotheses in a 3-year garden experiment with four perennials (Hypochaeris radicata, Cirsium dissectum, Succisa pratensis and Centaurea jacea) by growing them in the midst of a tall tussock-forming grass (Molinia caerulea) that may successionally replace them in their natural habitat. In all species except for the short-lived H. radicata, costs of sexual reproduction were significant over the 3 years, since continuous bud removal enhanced total biomass or rosette number. To mimic succession we added nutrients, which resulted in a tripled grass biomass and higher death rates in the shorter-lived species. The simulated succession resulted also in a number of coupled growth responses in the survivors: enhanced plant size as well as elevated seed production. The latter was partly due to larger plant sizes, but mostly due to higher reproductive allocation, which in turn could be partly explained by lower relative somatic costs and by lower root-shoot ratios in the high-nutrient plots. Our results suggest that perennial plants can increase both their persistence and their colonization ability by simultaneously increasing their vegetative size and reproductive allocation in response to enhanced competition and nutrient influxes. These responses can be very important for the survival of a species in a metapopulation context.

Asteraceae↗

PubMed2005

Diversity-productivity relationships: initial effects, long-term patterns, and underlying mechanisms.

A common pattern emerging from studies on the relationship between plant diversity and ecosystem functioning is that productivity increases with diversity. Most of these studies have been carried out in perennial grasslands, but many lasted only two growing seasons or reported data from a single year. Especially for perennial plant communities, however, the long-term effects of diversity are important. The question whether interactions between few species or among many species lead to increased productivity remained largely unanswered. So far, the main mechanism addressed is the increased input of nitrogen by nitrogen-fixing legumes. We report that other mechanisms can also generate strong increases of productivity with diversity. Results from 4 consecutive years of a plant diversity experiment without legumes show that a positive relationship between plant species richness and productivity emerged in the second year and strengthened with time. We show that increased nutrient use efficiency at high species richness is an important underlying mechanism. This mechanism had not been discussed in earlier studies. Furthermore, our results suggest that complementary nutrient uptake in space and time is important. Together, these mechanisms sustain consistently high productivity at high diversity.

Biodiversity↗

PubMed2004

Declining biodiversity in agricultural landscapes and the effectiveness of agri-environment schemes.

Agricultural intensification, greatly accelerated as a result of the EU Common Agricultural Policy (CAP), has led to drastic reductions in the populations of many wild plant and animal species that used to be characteristic of farmland. In 1992, the EU provided the member states with its Agri-environment Regulation 2078/92 to help member states reverse these developments by means of agri-environment schemes. The question is: will the implementation of these schemes be sufficient to restore the biological diversity on farmland? Most studies that have examined the effectiveness of agri-environment schemes have focussed on farmland birds in Great Britain and The Netherlands. So far, the positive effects appear to be limited. Continuous evaluation and adaptation of these schemes is needed to enable the biodiversity on farmland to recover from the EU's former policy.

Agriculture↗

PubMed2003

Phylogeny and taxonomy of root-inhabiting Cryptosporiopsis species, and C. rhizophila sp. nov., a fungus inhabiting roots of several Ericaceae.

Three Cryptosporiopsis species have thus far been isolated from roots of woody plants. A fourth species, which was recently isolated from roots of Calluna vulgaris, Erica tetralix, Vaccinium vitis-idaea, and V. myrtillus in The Netherlands, is described here as new. Sporulation on the natural substratum has not been observed and the morphological description of this fungus is therefore based on characters expressed on oatmeal and malt extract agars. The phenotypic characters indicated a close relationship with the other root-inhabiting species of Cryptosporiopsis and species of the associated teleomorph genus Pezicula. This relationship was confirmed by phylogenetic analyses using sequence data of the 5.8S nuclear rDNA and flanking internal transcribed spacers. In order to facilitate recognition of this possibly under-recognized category of root inhabitants, a key to the root-inhabiting Cryptosporiopsis species based on characters in vitro is given.

Ascomycota↗