Author: John Thomas Curtis
Publisher: Univ of Wisconsin Press
Published: 1959-11-15
Total Pages: 718
ISBN-13: 9780299019402
DOWNLOAD EBOOK →One of the most important contributions in the field of plant ecology during the twentieth century, this definitive survey established the geographical limits, species compositions, and as much as possible of the environmental relations of the communities composing the vegetation of Wisconsin.
Author: Benjamin George Wagner
Publisher:
Published: 1951
Total Pages: 128
ISBN-13:
DOWNLOAD EBOOK →Author: Amy O. Alstad
Publisher:
Published: 2017
Total Pages: 230
ISBN-13:
DOWNLOAD EBOOK →Plant communities respond to a number of different ecological drivers, and understanding the relative effects of such drivers is critical to informing effective conservation and management in an era of pronounced global change. However, documenting patterns of change in communities is often hindered by the scarcity of historical data. In this dissertation, I use a unique, historical dataset on plant community composition in Wisconsin prairie remnants to document conspicuous shifts in these plant communities. I replicate survey methods used by the original researchers in 1950 and 1987 to survey 47 remnant grasslands for a third time, in 2012. To assess the role of ecological drivers, I contacted landowners and land managers to obtain records of fire at each site, and used historical and contemporary landscape imagery to quantify landscape connectivity and patch size. I relate these drivers to various plant community metrics to examine the relative impacts of each driver, and whether these roles have shifted over time. I use data on plant functional traits to test if these characteristics relate to gains or losses in species occurrences. I also conducted a fully randomized field experiment to ask whether seed size and site preparation method relate to establishment success. This historical dataset reveals substantial changes in community composition, and also demonstrates that the pace of change has increased. Annual rates of local colonization and extinction accelerated by 129% and 214% respectively between 1950-1987 and 1987-2012, despite the fact that the second interval is >30% longer. Two anthropogenic drivers, patch area and fire history, increased in importance between these periods, whereas soil moisture declined in importance over the same period. Frequently burned sites were more stable (i.e., diverged less) over time with respect to both functional and taxonomic dissimilarity. Although total species richness at each site remains similar, their floristic composition continues to diverge, reflecting local extirpations and colonizations of particular groups of species. Most colonization events represent non-native species, which have increased in relative proportion across all sites by more than 500% between 1950 and 2012. Gains in non-native species were accompanied by losses of native species, with short-statured and small-seeded species disappearing particularly quickly. Contemporary species richness in these remnant grasslands is positively related to patch size. I expected to find a similarly positive relationship between species richness and connectivity, but this prediction is only supported by frequently burned sites. Unburned sites demonstrate no relationship between connectivity and species richness. This pattern may be the result of leaf litter, which accumulates in unburned grasslands, and serves as a major barrier to seedling establishment. Indeed, in the seed addition experiment, rates of successful seedling establishment were 2.6 times higher in plots that were burned prior to planting compared to plots that were unburned. Fewer than one percent all of the seeds sown into our experimental plots were detected as established seedlings in the two seasons following seed addition, demonstrating that the seed to seedling transition is a major bottleneck for plants in this system. Overall, this dissertation contributes to our knowledge of patterns and drivers of long-term change in remnant plant communities, and helps inform effective management and conservation strategy.
Author:
Publisher:
Published: 1997
Total Pages: 92
ISBN-13:
DOWNLOAD EBOOK →This volume represents a first attempt at holistically classifying and mapping ecological regions across all three countries of the North American continent. A common analytical methodology is used to examine North American ecology at multiple scales, from large continental ecosystems to subdivisions of these that correlate more detailed physical and biological settings with human activities on two levels of successively smaller units. The volume begins with an overview of North America from an ecological perspective, concepts of ecological regionalization. This is followed by descriptions of the 15 broad ecological regions, including information on physical and biological setting and human activities. The final section presents case studies in applications of the ecological characterization methodology to environmental issues. The appendix includes a list of common and scientific names of selected species characteristic of the ecological regions.
Author:
Publisher:
Published: 2007-09
Total Pages: 140
ISBN-13:
DOWNLOAD EBOOK →Backpacker brings the outdoors straight to the reader's doorstep, inspiring and enabling them to go more places and enjoy nature more often. The authority on active adventure, Backpacker is the world's first GPS-enabled magazine, and the only magazine whose editors personally test the hiking trails, camping gear, and survival tips they publish. Backpacker's Editors' Choice Awards, an industry honor recognizing design, feature and product innovation, has become the gold standard against which all other outdoor-industry awards are measured.
Author: Daniel J Vogt
Publisher: CRC Press
Published: 1999-11-29
Total Pages: 400
ISBN-13: 1420049453
DOWNLOAD EBOOK →Forest certification has been widely accepted as a tool that would encourage industrial and non-industrial management of resources in an environmentally acceptable, socially beneficial and economically viable manner. Much has been written on certification yet five issues have been missing, which this book addresses: an analysis of the scientific ba