Martin Schnittler

Ecology and world distribution of Barbeyella minutissima(Myxomycetes).

On the basis of all accessible records from the literature and our own field observations and collections, the ecology of the rare myxomycete Barbeyella minutissima is described. Analysis of these data, derived mainly from the Northern Ammergauer Alps (Germany) and the Appalachian Mountains (USA: West Virginia, North Carolina), permit the microhabitat requirements of this myxomycete and its ecological associations with other myxomycetes and bryophytes to be elucidated in some detail. Barbeyella minutissima appears to have a distribution centred in montane spruce-fir forests, where it is regularly associated with three other species of myxomycetes - Colloderma oculatum, Lamproderma columbinum, and Lepidoderma tigrinum. Several leafy liverworts are associated with Barbeyella. Particularly noteworthy is Nowellia curvifolia, which seems to be an indicator organism for this myxomycete. A world distribution map of Barbeyella minutissima is provided, along with conclusions relating to the putative range of the species.

Ecology and Distribution of Myxomycetes

Abstract In this chapter, the results obtained from recent studies of myxomycete ecology are discussed, with special emphasis on their distribution patterns in particular habitats, the relationships that exist between myxomycetes and other organisms and the effect of disturbance events on myxomycete communities. It is important to note that most of the available data are based on collections of fruiting bodies, which probably represent (in a literal sense) only the tip of the iceberg because it is possible that these reflect only a minor fraction of the real diversity of myxomycetes in a particular habitat. Therefore, it appears unlikely that a single method will be universally applicable for assessing myxomycete diversity in all habitats and on all substrates. The approaches, techniques, and their potential limitations are discussed herein, along with recent advances (e.g., moist chamber cultures, environmental PCR, metagenomics and barcoding attempts) that have been applied to studies of myxomycete ecology and will undoubtedly increase our understanding of myxomycete communities in the future.

Biogeographical Patterns in Myxomycetes

Abstract This chapter discusses the adaptations of myxomycetes relating to spore dispersal, which is the key to understand distribution patterns in this group of protists. Several groups of protists form spores—small, spherical, durable cells released from fruiting bodies. Judged by the number of species, myxomycetes are the most successful group. Fruiting bodies in myxomycetes are primarily stalked to allow spores to dry out and become airborne. Compound fruiting bodies are a second evolutionary tendency to achieve spore release by means of animal vectors and appear parallel in several taxa. Since fruiting bodies are formed only under optimum conditions, species may have larger distribution ranges than indicated by fruiting bodies. In contrast, many morphospecies may be complexes of cryptic species, and these may have narrower ecological niches and thus narrower distribution ranges. In addition, molecular studies of widely distributed morphospecies provide evidence for limited gene flow within regional populations. As such, myxomycetes seem to follow the moderate endemicity model more than the ubiquist model of microbial distribution. Molecular investigations, such as barcoding, provide novel tools to differentiate species and may link the two separate species concepts in the group, the morpho- and the biospecies concept. Most likely, the number of described myxomycete morphospecies will increase steadily. Although field studies in myxomycetes have been carried out for more than 200xa0years, survey intensity is still very different for different regions of the world and for the methods used (direct observations versus moist chamber cultures). The existing data indicate that species diversity patterns in myxomycetes do not follow the “decreasing latitude—increasing diversity” trend that holds true for macroscopic organisms, with an apparent hot spot in southern temperate zones, especially broadleaved deciduous forests. The surprisingly distinct and diverse assemblages of myxomycetes in deserts point to precipitation as one of the major factors to explain these patterns.