MORPHOLOGICAL DEFORMATION IN PRESERVED SPECIMENS OF THE DEEP-SEA OCTOPUS GRANELEDONE

Although morphology of firm-bodied shallow-water octopuses resistspreservation-linked deformation, preservation and handling of deep-seaspecimens of Graneledone are hypothesized to deform specimensby accelerating fluid loss from mantle and arm tissues. Principalcomponents analysis finds that seven of 39 North Pacific specimensof the genus are exceptionally narrow; the remaining specimensshow considerable morphological variation, independent of timein preservation. Five exceptionally narrow specimens, including someparatypes of G. pacifica, were collected and preserved by thesame trawling study; a single unrecorded factor in their common preservationhistory may have caused their deformation. The high morphologicalvariation among the remaining specimens, seemingly unique amongoctopodids, may reflect factors as subtle as how the specimenwas stored in the jar. Two types of change with time in preservationare documented. The mantle wall of formalin-fixed specimensthins unpredictably after storage for 30 months in 70% ethanol,consistent with deformation in preservation. Skin tubercles onthe dorsal mantle, important taxonomic characters, become more prominentduring the first decade in preservation. To maximize the informationspecimens with fluid-rich tissues convey and to identify thesources of deformation, the full preservation history and measurementsmade prior to dissection should be permanently recorded. (Received 25 April 2000; accepted 25 July 2000)     

Evaluation of assisted colonization strategies under global change for a rare,fire‐dependent plant

As a clear consensus is emerging that habitat for many species will dramatically reduce or shift with climate change, attention is turning to adaptation strategies to address these impacts. Assisted colonization is one such strategy that has been predominantly discussed in terms of the costs of introducing potential competitors into new communities and the benefits of reducing extinction risk. However, the success or failure of assisted colonization will depend on a range of population‐level factors that have not yet been quantitatively evaluated – the quality of the recipient habitat, the number and life stages of translocated individuals, the establishment of translocated individuals in their new habitat and whether the recipient habitat is subject to ongoing threats all will play an important role in population persistence. In this article, we do not take one side or the other in the debate over whether assisted colonization is worthwhile. Rather, we focus on the likelihood that assisted colonization will promote population persistence in the face of climate‐induced distribution changes and altered fire regimes for a rare endemic species. We link a population model with species distribution models to investigate expected changes in populations with climate change, the impact of altered fire regimes on population persistence and how much assisted colonization is necessary to minimize risk of decline in populations of Tecate cypress, a rare endemic tree in the California Floristic Province, a biodiversity hotspot. We show that assisted colonization may be a risk‐minimizing adaptation strategy when there are large source populations that are declining dramatically due to habitat contractions, multiple nearby sites predicted to contain suitable habitat, minimal natural dispersal, high rates of establishment of translocated populations and the absence of nonclimatic threats such as altered disturbance regimes. However, when serious ongoing threats exist, assisted colonization is ineffective.     

THE APPLICATION OF TWO FREE-CHOICE PROFILE METHODS TO INVESTIGATE THE SENSORY CHARACTERISTICS OF CHOCOLATE

The concept of free-choice profiling allows untrained assessors to participate in sensory profiling. However, it is sometimes the case that such individuals are unable to describe what they perceive when the samples are presented in the isolation of the sensory testing booths. This paper reports an experiment to compare the usual free-choice profile procedure, with a more structured approach based on Kelly's repertory grid method. Generalized Procrustes analysis was used to analyse the data. The sample configurations obtained from both approaches were very similar, as were the interpretations of the main perceptual dimensions.     

Surface nitrogen and plankton in Skaha Lake, British Columbia (Canada)

This study (1970–71) of an oligotrophic lake subject to cultural enrichment indicates the presence of complex interrelations between plankton and nitrogen levels in surface waters. Generally inorganic nitrogen was high in the winter (0.4–0.5 ppm) and Iow in summer (less than 0-1 ppm). However, in late July and August a large increase in nitrogen (1.5 ppm) was recorded. This correlated with the Gloeotrichia echinulata J. E. Smith ex P. Richt. bloom (Cyanophyceae) and the increase in nitrogen fixation, or nitrogenase activity (measured as acetylene reduction). It was calculated that the cyanophyte bloom could have contributed a minimum of 2350 kg nitrogen to the lake in August 1970 which is c. 62% of the nitrate-nitrogen occurring at any time.