Development and evaluation of a system for tracking wildlife by satellite
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The narrow-leaved cattail wetland known as Dyke Marsh formally became a land holding of George Washington Memorial Parkway (GWMP, a unit of the national park system) in 1959, along with a congressional directive to honor a newly-let 30-year commercial sand and gravel dredge-mining lease at the site. Dredging continued until 1974 when Public Law 93-251 called for the National Park Service and the United States Army Corps of Engineers to “implement restoration of the historical and ecological values of Dyke Marsh.” By that time, about 83 acres of the marsh remained, and no congressional funding accompanied the passage of the law to effect any immediate conservation or restoration. Decades of dredge mining had severely altered the surface area of Dyke Marsh, the extent of its tidal creek system, and the shallow river bottom of the Potomac River abutting the marsh. Further, mining destabilized the marsh, causing persistent erosion, shoreline retreat, and tidal channel widening after mining ceased. Erosion has continued unchecked until the present; approximately 50 acres of the original marsh are now estimated to remain. The specific cause of persistent erosion had been unknown prior to this collaborative study but previously was assumed to be due to flooding by the Potomac River.
Lisbon Bottom consists of approximately 875 ha of river bottom along the Missouri River in Howard County, Missouri, from approximately river mile (RM) 213 to RM 219. As used in this report, the Lisbon Bottom area also includes the main channel of the Missouri River adjacent to the Lisbon Bottom and portions of the adjacent flood plain in Saline County, Missouri. Before regulation and structuring of the Missouri River, riverine areas like Lisbon Bottom were shifting mosaics of dynamic habitat patches that were created and maintained by hydrologic and geomorphic processes. Flow regulation, navigation structures, and bank-stabilization projects isolated Lisbon Bottom from the river by decreasing the magnitude and frequency with which hydrologic and geomorphic processes could alter habitat characteristics. The flood of 1993 breached agricultural levees around Lisbon Bottom, thereby reestablishing a connection to the Missouri River. Although still affected by flow regulation and the requirement to maintain navigation in the main channel, Lisbon Bottom presents the opportunity to study ecosystem processes and dynamic geomorphology in a setting that more closely mimics the natural riverine system than any other site on the navigable Lower Missouri River. The purpose of this chapter is to describe the physical setting and processes that structure the riverine ecosystem of Lisbon Bottom and similar areas of the Lower Missouri River. The description compiles available information on temporal and spatial changes at the site, including the history of channel changes and hydrology.
Coastal ecosystems in the eastern U.S. have been severely altered by processes associated with human development, including drainage of coastal wetlands, changes in hydrology that alter sediment and freshwater delivery to the coast, land clearing, agricultural and forestry activity, and the construction of seawalls and other structures that “harden” the coast. Sea-level rise and the changing frequency of extreme events associated with climate change are now further degrading the capacity of those ecological and social systems to remain resilient in the face of disturbance, largely through the degradation and loss of land and habitat. The goal was to develop a problem framing that would broadly reflect the type, scale and scope of SLR-adaptation decisions faced by refuges in general, and that could be used by individual refuges to help understand how their specific problems fit into a larger context of SLR planning and implementation. We worked with refuge managers in developing a common frame of reference for some shared SLR-related management problems, while also facilitating communication about these problems with other refuges and with surrounding jurisdictions.
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Natural history and field ecology are essential building blocks for successful conservation and management of herpetofauna. Thus, natural history and field ecology merit major infusions of funding and increased recognition of their importance in science and management. Others have stated matters well: (1) Academic training in natural history should receive high priority; (2) we need to integrate our work across disciplines (from molecules to communities), and use all of our knowledge toward common goals; (3) natural history is not dead but today is a flourishing enterprise; and (4) mutual respect and collaboration between disciplines best serve our own mental health as well as the future of natural history. We need to merge the best natural history, field ecological data, and biological questions with the latest advances in other fields of inquiry if we are to advance science and solve key environmental issues. It takes a scientific community and many concerned parties to save a species, let alone an ecosystem. We must connect these dots to see the big picture.
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From the time that western civilization established itself on the North American continent until very recent years, little thought was given to the diseases, or other forms of loss, in game. In the process of bringing civilization and the incidental domestic arts and trades to the United States it appears to have been the policy to establish domestic farm stock on the land just as abundantly as the carrying capacity of land would tolerate. And judged by the low quality of many of our present farm animals, it is evident that in many cases the land was, and is now, overstocked and undermanaged. In traveling over this country one is impressed by the lack of uniformity, imperfect physical development, and poor state of nutrition of much of the domestic livestock. It would appear that the wild animals unhampered by fencing and other restraint such as controlled mating, feed selection, and enforced habitat in contaminated or polluted environment, have a better chance for perfect growth and complete development to a size and proportion normal for those species. While all of the factors mentioned produce a definitely deleterious result on the welfare of animal life, that of contaminated or polluted environment is by no means the least. The stunting action of disease on the growth of the young is too well known to admit of controversy. The impairment of function of vital organs due to minute cellular changes resulting from sub-acute or chronic infections prevents normal growth. Through centuries of enforced survival in densely congested pastures, pens, and stables, a certain degree of acquired resistance to many diseases has been built up in farm stock. If it were not so, very few barnyard animals would ever survive the conditions generally seen in our agricultural districts. Manure heaps, quantities of partly spoiled feed, and decaying masses of vegetation and refuse have come to be regarded as a natural part of the barnyard scene.
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