Summary• The contribution of arbuscular mycorrhizas (AM) to plant community structure and diversity is reported here in an annual herbland in southern Australia.• Mycorrhizal colonization was reduced in field plots by applying the fungicide benomyl as a soil drench. The mycorrhiza-responsiveness of plant species was assessed in intact soil cores containing the indigenous AM fungi and in a pot experiment using an isolate of Glomus mosseae .• Glasshouse experiments showed that Medicago minima, Vittadinia gracilis and Velleia arguta were highly mycorrhiza-responsive, Salvia verbenaca became colonized but exhibited no growth response to AM, and Carrichtera annua remained uncolonized. There was no change in plant species richness in mycorrhizasuppressed field plots but diversity increased owing to an increase in evenness. Treatment had no effect on community productivity and therefore there was no relationship between mycorrhizal effects on diversity and productivity.• Mycorrhizal responsiveness was not a good predictor of species response to suppression of AM in the field. The mycorrhiza-responsive species V. gracilis and V. arguta were not affected by reduced mycorrhizal colonization in fungicide-treated plots, suggesting that competition from the mycorrhiza-responsive dominant M. minima offset the benefits of mycorrhizal association for these species.

Conservation monitoring in Australia has assumed increasing importance in recent years, as societal pressure to actively manage environmental problems has risen. More resources than ever before are being channelled to the task of documenting environmental change.Yet the field remains crippled by a pervasive lack of rigour in analysing, reporting and responding to the results of data collected. Millions of dollars are currently being wasted on monitoring programmes that have no realistic chance of detecting changes in the variables of interest. This is partly because detecting change in ecological systems is a genuinely difficult technical and logistical challenge. However, the failure to plan, fund and execute sophisticated analyses of monitoring data and then to use the results to improve monitoring methods, can also be attributed to the failure of professional ecologists, conservation practitioners and bureaucrats to work effectively together. In this paper, we offer constructive advice about how all parties involved can help to change this situation. We use three case studies of recent monitoring projects from our own experience to illustrate ways in which the disconnect between science and bureaucracy can be bridged and some obstacles to collecting and analysing ecologically meaningful data sets can be overcome. We urge a continuing discussion on this issue and hope to stimulate a change in the culture of conservation monitoring in Australia.

The GEMAS (geochemical mapping of agricultural soil) project collected 2108 Ap horizon soil samples from regularly ploughed fields in 33 European countries, covering 5.6 million km2. The <2 mm fraction of these samples was analysed for 53 elements by ICP-MS and ICP-AES, following a HNO3/HCl/H2O (modified aqua regia) digestion. Results are used here to establish the geochemical background variation and threshold values, derived statistically from the data set, in order to identify unusually high element concentrations for these elements in the Ap samples. Potentially toxic elements (PTEs),

SummaryThis paper reports the successful isolation and preliminary characterisation of a mutant of Lycopersicon esculentum Mill. with highly reduced vesicular-arbuscular (VA) mycorrhizal colonization. The mutation is recessive and has been designated rmc. Colonization by G. mosseae is characterised by poor development of external mycelium and a few abnormal appressoria. Vesicles were never formed by this fungus in association with the mutant. Gi. margarita formed large amounts of external mycelium, complex branched structures and occasional auxiliary cells. Small amounts of internal colonization also occurred. Laser scanning confocal microscopy (LSCM) gave a clear picture of the differences in development of G. intraradices and Gi. margarita in mutant and wild-type roots and confirmed that the fungus is restricted to the root surface of the mutants. The amenability of tomato for molecular genetic characterisation should enable us to map and clone the mutated gene, and thus identify one of the biochemical bases for inability to establish a normal mycorrhizal symbiosis. The mutant represents a key advance in molecular research on VA mycorrhizal symbiosis.

Conservation tenders are being used as a policy mechanism to deliver environmental benefits through changes in land, water and biodiversity management. While these mechanisms can potentially be more efficient than other agri-environmental and payment for ecosystem service schemes, a key limitation in practice is that participation rates from eligible landholders are often low, limiting both efficiency and effectiveness. In this paper we document and review potential causes of low participation in two categories: those that treat participation as an adoption issue focused on searching for the landholder, farm or practice characteristics that limit participation; and those that treat it as an auction design issue, looking for the different auction, contract or transaction cost elements that limit landholder interest in participation. We then model how landholders make choices to engage and bid in a tender, making three important contributions to the literature on this topic. First, we document the low participation rates in conservation tenders, mostly across developed countries, an issue that has received little attention to date. Second, we explain that a decision to participate in a conservation tender involves three simultaneous decisions about whether to change a management practice, whether to be involved in a public or private program with contractual obligations, and how to set a price or bid. Third, we explain that there are a number of factors that affect each stage of the decision process with some, such as landholder attitudes and risk considerations, relevant to all three. Our findings suggest that decisions to participate in a conservation tender are more complex than simple adoption decisions, involving optimisation challenges over a number of potentially offsetting factors.