Reintroducing capercaillie (Tetrao urogallus) into southern Scotland: identification of minimum viable populations at potential release sites

Capercaillie (Tetrao urogallus) populations are declining in western parts of their range, including Scotland. It has been proposed that their numbers, and the extent of their range in Scotland be increased to reduce the risk of a second extinction in the UK. The feasibility of a reintroduction of capercaillie to coniferous plantations in southern Scotland was assessed by undertaking a population viability analysis. Following a review of capercaillie ecology and habitat requirements, VORTEX population simulation software was used to identify a minimum viable population (MVP). From this the minimum dynamic area of suitable habitat required in order to support such a MVP was then calculated. It was estimated that a minimum of 60 individuals would be required in approximately 5000ha of habitat in order for the population to have a >0.95 probability of surviving for 50 years. Supplementation of populations with two unrelated individuals every five years reduced the MVP to ten individuals. Further simulations were run in order to establish the sensitivity of the model to changes in three key parameters. Assessment of areas of suitable habitat identified two potential release sites, Wauchope and Newcastleton forests, in southern Scotland. Some practical considerations relating to management of a release population are outlined. It was concluded that an appropriately planned and resourced reintroduction was feasible.     

Is maximum sustainable yield independent of body size for mammals (and others)?

Summary Provided carrying capacity (K) for non-primate mammals scales with the –0.75 power of adult body weight (W), MSY (in weight) should be approximately one-sixth ofC, whereC is defined byK =CW ^–0.75.     

Equilibria and dynamics of selection at a diallelic autosomal locus in the Nagylaki-Crow continuous model of a monoecious population

Let birth rates and death rates be constant, birth rates positive, fertilities additive, and each birth rate not larger than twice any other birth rate. Global convergence to equilibria is proved for the model in the title. There is at most one polymorphic equilibrium or there are a continuum of equilibria. The phase portraits are given. If there is a polymorphic equilibrium, then the largest negatively invariant set in the state space is a continuous curve connecting the two fixation equilibria. This curve coincides with the Hardy-Weinberg manifold exactly when the death rate is additive. Disregarding extinction, the polymorphic equilibria are the same for the continuous model as for the corresponding discrete model exactly when the death rate is additive.     

Acoustic assessment of the number of pelagic fish in Lake Kinneret,Israel

The pelagic fish stock (mostly lavnun, Mirogrex terraesanctae) of Lake Kinneret was assessed using HADAS, a newly developed echo-counting analysis system. Total fish numbers (during Mar–Apr) were estimated to be 61 million in 1987, 218 million in 1988, 120 million in 1989, and 69 million in April 1990. The total fish number for March 1981 was recalculated from published data and estimated at 170 million. The decline in total numbers between 1988 and 1990 resulted primarily from a decrease in the relative abundance of the smallest size classes of fish. Since fish abundance apparently declined between 1981 and 1990, the decline in zooplankton standing stocks documented during these years cannot be attributed to higher fish predation caused by larger fish stocks. The HADAS estimates of lavnun population size are large enough to account for the known catch of lavnun.Contribution from Israel Oceanographic & Limnological Research, Ltd. This research was supported in part by the Israeli Water Commissioner, the Israeli Electric Company, and by a grant from the U.S. Agency for International Development.     

Meaning in Nature: Organic Manufacture?

The paper examines Marcello Barbieri’s (2007) Introduction to Biosemiotics. Highlighting debate within the biosemiotic community, it focuses on what the volume offers to those who explain human intellect in relation to what Turing called our ‘physical powers.’ In scrutinising the basis of world-modelling, parallels and contrasts are drawn with other work on embodied-embedded cognition. Models dominate biology. Is this a qualitative fact or does it point to biomechanisms? In evaluating the 18 contributions, it is suggested that the answers will shape the field. First, they will decide if biochemistry and explanatory reduction can be synergised by biosemantics. Second, they will show if our intellectual powers arise from biology. Does thinking use—not a language faculty—but what Marko? and colleagues call semiosis by the living? Resolution of such issues, it is suggested, can change how we view cognition. Above all, if the biomechanists win the day, cultural models can be regarded as extending natural meaning. On such a view, biomechanisms prompt us to act and perceive as we model our own natural models. This fits Craik’s vision: intellect gives us the alphanumerical ‘symbols’ that allow thoughts to have objective validity. For the biomechanist, this is explained—not by brains alone—but, rather, by acting under the constraints of historically extended sensoria.     

Estimation of density of gibbon groups by use of loud songs

The density of gibbon populations may be estimated by listening for the loud duetted songs of monogamous territorial groups. This method requires a correction factor which must be estimated from the frequency of singing of an adequate number of known study groups. The correction factor and its error were estimated for pileated gibbons (Hylobates pileatus) in Khao Soi Dao Wildlife Sanctuary in southeastern Thailand. Among 30 groups studied, 47% sang per day, on average, but the variation between days and the variation in singing frequency between groups were large. Weather conditions, especially windiness, explained some variation in singing. During an area-wide survey of groups in the sanctuary, unexplained variation in singing from day to day accounted for approximately half of the sample error of group density estimated from 1-day listening samples. Error due to day-to-day variability can be reduced by listening for more than one day at each site. Correction factors based on the cumulative proportion of groups heard during longer (2–5-day) sample periods of listening were closer to 1.0, therefore leaving less room for error and bias of the correction factor. © 1993 Wiley-Liss, Inc.     

Gene flow among Tetranychus urticae (Acari: Tetranychidae) populations in Greece

Polymorphism of four enzymatic loci has been examined in 27 populations of Tetranychus urticae in relation to their geographical distribution and to two ecological parameters: open field vs. greenhouse habitats, and species of the colonized host plant. Genetic differentiation was significantly correlated to geographical distance in both types of habitat. Mite density and distribution of infested plants appear to be important factors for the population structure of T. urticae . In open field, T. urticae specimens from citrus trees were genetically more similar to other 'citrus' samples collected in different localities than they were from mites collected in the same locality on other plant species.     

Algorithm of Regulatory Signal Recognition in DNA Sequences

An algorithm is proposed for extracting regulatory signals from DNA sequences. The algorithm complexity is nearly quadratic. The results of testing the algorithm on artificial and natural sequences are presented.     

Ultraviolet radiation, toxic chemicals and amphibian population declines

Abstract. As part of an overall ‘biodiversity crisis’, many amphibian populations are in decline throughout the world. Numerous factors have contributed to these declines, including habitat destruction, pathogens, increasing ultraviolet (UV) radiation, introduced non‐native species and contaminants. In this paper we review the contribution of increasing UV radiation and environmental contamination to the global decline of amphibian populations. Both UV radiation and environmental contaminants can affect amphibians at all life stages. Exposure to UV radiation and to certain contaminants can kill amphibians and induce sublethal affects in embryos, larvae and adults. Moreover, UV radiation and contaminants may interact with one another synergistically. Synergistic interactions of UV radiation with contaminants can enhance the detrimental effects of the contaminant and UV radiation.