The Shifting of Ecological Restoration Benchmarks and Their Social Impacts: Digging Deeper into Pleistocene Re‐wilding

Current and projected rates of species loss prompt us to look for innovative conservation efforts. One such proposal is that large areas of North America be re‐wilded with old world species that descended from Pleistocene mega‐fauna. We argue that this approach overlooks many important ecological, evolutionary, cultural, and economic issues and detracts from conservation efforts by adding another arbitrary restoration benchmark. Our objectives are to specifically address the shifting benchmark for ecological restoration, explore the social dimensions of Pleistocene re‐wilding, which have been largely overlooked, and discuss why we think Pleistocene re‐wilding is not a proactive approach for conservation. This is not intended as a critique of innovative approaches. Instead it is an argument that human and ecological factors need to be considered in depth before any restoration initiative can be practically implemented. Proactive approaches should consider historical conditions while managing based on the present, should plan for the future, and should allow adaptation to changing conditions. We support the strategy to restore ecological interactions using species that coevolved with these interactions, bearing in mind the complexities of the socio‐ecological dimensions of any management action.     

The response to disturbance chemicals and predator odours of juvenile and adult signal crayfish Pacifastacus leniusculus (Dana)

Many species of crayfish have been shown to use disturbance chemicals to detect the presence of predators and other dangers, yet there have been no investigations in adults or juveniles of Pacifastacus leniusculus, a key species, particularly for invasive species study. Juveniles and adults were exposed to conditioned water from stressed and damaged conspecific males. Both responded to these odours, but did not respond to water from stressed or damaged males with blocked nephropores. Urine from stressed and damaged males also elicited a significant response, which was much stronger than that of conditioned water. Odours from urine and water of damaged individuals induced a greater response than stress odours. We propose that chemicals released by stressed or damaged Pa. leniusculus are the same substance, but quantities released in the urine vary in context-specific circumstances. Predator-odour conditioned water from Perca fluviatilis elicited no response, but conditioned Anguilla anguilla water stimulated significant responses in juveniles and adults. Juveniles exhibited the strongest responses to all odours. These results show that Pa. leniusculus utilises both conspecific and heterospecific sources of info-chemicals to assess risk in the environment, which may contribute to its success as an invasive species and give it a competitive advantage.     

The conversion of S-adenosyl-l-methionine to stipitatic acid by extracts of Penicillium stipitatum

Cell-free extracts prepared from acetone powders of Penicillium stipitatum contain an enzyme system converting [¹⁴CH₃]-S-adenosyl-l-methionine to radioactive stipitatic acid; the estimated molecular weight is 105 000. The incorporated radio-activity is located at C-7 of the tropolone ring. Addition of putative acceptor compounds had little or no influence on tropolone synthesis. Methylation appears to be an early step in tropolone biosynthesis in this organism.