50 research outputs found
Three new tree-frogs from Panama and Bolivia
http://deepblue.lib.umich.edu/bitstream/2027.42/56646/1/OP207.pd
A new Gastrotheca from Venezuela
http://deepblue.lib.umich.edu/bitstream/2027.42/56546/1/OP107.pd
A new frog from British Guiana
http://deepblue.lib.umich.edu/bitstream/2027.42/56615/1/OP176.pd
Observations upon the habits of Ascaphus truei Stejneger
http://deepblue.lib.umich.edu/bitstream/2027.42/56523/1/OP084.pd
Observations on Typhlops from Puerto Rico and some of the adjacent islands
http://deepblue.lib.umich.edu/bitstream/2027.42/56746/1/OP307.pd
The reptiles and amphibians collected in northeastern Nevada by the Walker-Newcomb Expedition of the University of Michigan
http://deepblue.lib.umich.edu/bitstream/2027.42/56447/1/OP008.pd
Notes on a collection of amphibians and reptiles from eastern Nicaragua
http://deepblue.lib.umich.edu/bitstream/2027.42/56796/1/OP357.pd
Why do authoritarian regimes provide public goods? Policy communities, external shocks and ideas in Chinaâs rural social policy making
Recent research on authoritarian regimes argues that they provide public goods in order to prevent rebellion. This essay shows that the âthreat of rebellionâ alone cannot explain Chinese party-state policies to extend public goods to rural residents in the first decade of the twenty-first century. Drawing on theories of policy making, it argues that Chinaâs one-party regime extended public goods to the rural population under the influence of ideas and policy options generated by policy communities of officials, researchers, international organisations and other actors. The party-state centre adopted and implemented these ideas and policy options when they provided solutions to external shocks and supported economic development goals. Explanations of policies and their outcomes in authoritarian political systems need to include not only âdictatorsâ but also other actors, and the ideas they generate
Effects of soil warming and nitrogen foliar applications on bud burst of black spruce
Key message: In mature black spruce, bud burst process is anticipated by soil warming, while delayed by foliar applications of nitrogen; however, the effects depend on growth conditions at the site.
Abstract: The observation of phenological events can be used as biological indicator of environmental changes, especially from the perspective of climate change. In boreal forests, the onset of the bud burst is a key factor in the length of the growing season. With current climate change, the major factors limiting the growth of boreal trees (i.e., temperature and nitrogen availability) are changing and studies on mature trees are limited. The aim of this study was to investigate the effects of soil warming and increased nitrogen (N) deposition on bud burst of mature black spruce [Picea mariana (Mill.) BSP]. From 2008 onwards, an experimental manipulation of these environmental growth conditions was conducted in two stands (BER and SIM) at different altitudes in the boreal forest of Quebec, Canada. An increase in soil temperature (H treatment) and a canopy application of artificial rain enriched with nitrogen (N treatment) were performed. Observations of bud phenology were made during MayâJuly 2012 and 2013. In BER, H treatment caused an anticipation (estimated as 1â3 days); while N treatment, a delay (estimated as 1â2 days but only in 2012) in bud burst. No treatments effect was significant in SIM. It has been demonstrated that soil temperature and N availability can play an important role in affecting bud burst in black spruce but the effects of these environmental factors on growth are closely linked with site conditions