Expansion of Canopy-Forming Willows Over the Twentieth Century on Herschel Island, Yukon Territory, Canada

Canopy-forming shrubs are reported to be increasing at sites around the circumpolar Arctic. Our results indicate expansion in canopy cover and height of willows on Herschel Island located at 70° north on the western Arctic coast of the Yukon Territory. We examined historic photographs, repeated vegetation surveys, and conducted monitoring of long-term plots and found evidence of increases of each of the dominant canopy-forming willow species (Salix richardsonii, Salix glauca and Salix pulchra), during the twentieth century. A simple model of patch initiation indicates that the majority of willow patches for each of these species became established between 1910 and 1960, with stem ages and maximum growth rates indicating that some patches could have established as late as the 1980s. Collectively, these results suggest that willow species are increasing in canopy cover and height on Herschel Island. We did not find evidence that expansion of willow patches is currently limited by herbivory, disease, or growing conditions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13280-011-0168-y) contains supplementary material, which is available to authorized users

An introduction to Dangerous ideas in zoology

Dangerous ideas are those that challenge the status quo, ignore political correctness or, if followed, lead to an unsettling series of consequences (Pinker 2006). As practising zoologists, our ongoing concern relates to the long-term survival of our native wildlife across all land tenures and the marine environment, and protecting natural areas in perpetuity. We hoped that a day of dangerous zoological ideas would stimulate fresh thinking and discussion about how to meet the challenges in using science to help conserve wildlife in the 21st century. While we as editors have a view on what comprises a dangerous idea (and a solid zoological idea), we were most reluctant to circumscribe our speakers and their papers. As a consequence, the papers in this volume reveal a remarkable take on what is dangerous, or at least what is considered dangerous and by whom. Some authors pose dangerous new ideas to solve difficult zoological challenges, others highlighted dangers in the misinterpretation of science and make a call for change, while others revealed hidden dangers in zoological ideas that are popular with the public but are yet to be fully thought through. Collectively the papers in this volume reveal that within the discipline of zoology, the battleground of ideas is awash with tough contests. Here though, our focus is on understanding and conserving our native fauna and, to that end, the Royal Zoological Society of NSW is keen to be dangerous in a world locked more into economic growth than an appreciation of our natural heritage and how to conserve it

Zoology on the table: the science, sustainability and politics of eating animals

Short Surve

Noise with memory as a model of lemming cycles

87.23.Cc Population dynamics and ecological pattern formation, 02.50.Ey Stochastic processes, 05.40.Ca Noise,

Changes in abundance and reproductive activity of small arid zone murid rodents on an active cattle station in central Australia

Context. Boom and bust population cycles are characteristic of many arid-zone rodents, but it is unknown to what extent these dynamics might be influenced by the presence of invasive rodents, such as the house mouse (Mus musculus) in Australia. Aim. To determine whether the presence of M. musculus can have negative consequences on the population abundance and reproduction of two old Australian endemic rodents (the spinifex hopping mouse, Notomys alexis, and sandy inland mouse, Pseudomys hermannsburgensis). Methods. The study took place on the sand dunes of a cattle station in central Australia. Population abundance was estimated as the number of individuals caught in small mammal traps, and female reproductive condition by external examination and, in a few cases, euthanasia and inspection of the reproductive tract. Key results. Two synchronous periods of high abundance of N. alexis and M. musculus occurred several months after significant rainfall events, whereas the abundance of P. hermannsburgensis was consistently low.Noreproduction took place in N. alexis or M. musculus when populations had reached high abundance. During low-rainfall periods, M. musculus was not detected on the sand dunes, and the two endemic species were sparsely distributed, with reproduction occasionally being evident. Conclusions. During dry periods, M. musculus contracted back to refuges around the homestead and, after significant rainfall, it expanded onto the sand dunes and became abundant at the same time as did N. alexis. In contrast, and unlike in areas where M. musculus was generally rare, P. hermannsburgensis always remained at a low abundance. These patterns suggest that in areas of the natural environment close to human-modified sites, populations of at least one species of an old endemic rodent are supressed by the presence of M. musculus. Reproduction did not occur in the old endemics at times of high M. musculus abundance, but did take place in spring/early summer, even in some dry years. Implications. The spread of M. musculus into the Australian arid zone may have had negative impacts on the population dynamics of P. hermannsburgensis. These findings suggest that the presence of human settlements has resulted in refuges for house mice, which periodically spread out into the natural environment during ‘boom’ times and adversely affect the natural population cycle of ecologically similar species such as P. hermannsburgensis.W. G. Breed, C. M. Leigh and M. F. Bree