No abstract

Different responses of plants and herbivore insects to a gradient of vegetation height: an indicator of the vertebrate grazing intensity and successional age. Á Oikos 115: 401 Á412.Empirical studies have suggested that species richness of grassland insects usually decreases under grazing management. By contrast, grazing has been shown to increase the species density and richness of vascular plants, especially on productive soils. In order to test the suggested differences in response to management between plants and insects, we simultaneously studied species richness of vascular plants and their insect herbivores, butterflies and moths, in 68 semi-natural grasslands with varying grazing intensity and frequency in SW Finland. Species richness of plants and insects was for the first time related to a quantitative measure of disturbance intensity and successional age, mean vegetation height, by using generalized additive models (GAM). The effects of soil nutrients on vegetation height were accounted for by using phosphorus concentration as a productivity surrogate.The results showed that species richness of butterflies and moths peaked in taller vegetation compared with vascular plants, corresponding to a lower disturbance intensity and increasing time since abandonment. These patterns are discussed in the light of two hypotheses, the ''structural diversity hypothesis'' and ''dynamic equilibrium model'' of Huston, both suggesting a weaker disturbance tolerance of insects compared with plants. Butterflies and moths which are specialists in their larval host-plant use (monophagous and oligophagous species) preferred lower vegetation (higher disturbances) compared with generalists (polyphagous species), as predicted by Huston's model. This difference indicates a stronger relationship with plant species richness for specialist than for generalist butterflies and moths. Our results support the application of regionally and temporally varying grazing intensities in grassland conservation management.J. Pöyry (juha.poyry@ymparisto.fi),

A number of studies show contrasting results in how plant species with specific life‐history strategies respond to fragmentation, but a general analysis on whether traits affect plant species occurrences in relation to habitat area and isolation has not been performed. We used published data from forests and grasslands in north‐central Europe to analyse if there are general patterns of sensitivity to isolation and dependency of area for species using three traits: life‐span, clonality, and seed weight. We show that a larger share of all forest species was affected by habitat isolation and area as compared to grassland species. Persistence‐related traits, life‐span and clonality, were associated to habitat area and the dispersal and recruitment related trait, seed weight, to isolation in both forest and grassland patches. Occurrence of clonal plant species decreased with habitat area, opposite to non‐clonal plant species, and long‐lived plant species decreased with grassland area. The directions of these responses partly challenge some earlier views, suggesting that further decrease in habitat area will lead to a change in plant species community composition, towards relatively fewer clonal and long‐lived plants with large seeds in small forest patches and fewer clonal plants with small seeds in small grassland patches. It is likely that this altered community has been reached in many fragmented European landscapes consisting of small and isolated natural and semi‐natural patches, where many non‐clonal and short‐lived species have already disappeared. Our study based on a large‐scale dataset reveals general and useful insights concerning area and isolation effects on plant species composition that can improve the outcome of conservation and restoration efforts of plant communities in rural landscapes.

Livestock grazing (without modern fertilizers), mowing, and other traditional methods of animal husbandry are used in Europe for managing human‐made habitats such as seminatural grasslands. From a review of essential literature, I hypothesize that traditional animal husbandry partially compensates for the loss of natural processes that have been suppressed by humans. There is indirect evidence that livestock grazing and mowing have made possible the continued existence of many species threatened by the human overkill of megaherbivores and other large herbivores. Many species that were dependent on natural fires and floods may have benefited from grazing and mowing, which also may be effective tools for mitigating the negative effects of eutrophication. As partial surrogates, traditional grazing and mowing have obscured the importance of natural disturbances to European biodiversity. Thus, the end of traditional animal husbandry, together with the suppression of natural disturbances, may cause even more adverse effects to biodiversity than is generally recognized.

Recent molecular phylogenetic analyses and morphological studies have shown that it is necessary to revise the present morphology-based generic delineation of the lichen family Verrucariaceae in order to account for evolutionary relatedness between species. Consequently, several genera were recently described or resurrected, and others were re-circumscribed. As an additional step toward this generic revision, three new genera (Hydropunctaria, Parabagliettoa, Wahlenbergiella) and eleven new combinations are proposed here. A summary of the current taxonomic and morphological circumscription of all genera investigated so far is also presented. Several monophyletic groups are identified for which further taxonomical changes will be required, but for which taxon and gene sampling is presently viewed as insufficient. Clear morphological synapomorphies were found to be rare for newly delimited genera. In some cases (reduced morphology or plesiomorphism), even the combinations of slightly homoplasious phenotypic characters do not allow a clear morphological generic circumscription. Molecular features are envisioned as characters for delimiting these taxa.