66 research outputs found
Gully afforestation as a historical land management choice : regional insights from SW Ethiopia using 1938-57 aerial photographs
Forest distribution and site quality in southern Lower Michigan, USA
ABSTRACT Aim The primary objectives of this research were to determine whether current forest patches in southern Lower Michigan are a proportionate sample of forest types present in the pre-settlement cover and, if not, to establish the degree to which certain types are over-or under-represented in the contemporary landscape. This determination is useful not only because any conservation policy designed to restore the present forest to pre-settlement biodiversity through preservation of existing stands requires an accurate understanding of the degree to which these stands in sum mirror past forest diversity, but also because it fills a gap in the existing ecological literature. Location The research was conducted within four counties in southern Lower Michigan, USA (Ionia, Livingston, Tuscola and Van Buren). Methods Soil survey data were used to characterize the range of site quality across the study area and the areal extent of each quality category. The geographic locations of all current forest patches in each county were then determined from land use maps and were overlaid on the site quality classification. This procedure yielded the observed distribution of forest relative to site quality. The expected areal extent of forest within each category of site quality on the landscape was determined by assuming a random distribution and multiplying the total area of forestland by the proportion of landscape within each category of site quality. This procedure calculated the expected distribution of forest in terms of site quality by dividing the total forestland among the landscape types, relative to how well represented the landscape types were. The observed and expected distributions were then compared both in terms of absolute difference and normalized difference. Results Overall results indicate that categories of site quality that support a large proportion of the present-day forest patches are generally composed of agriculturally inferior soil and are over-represented with forest. Surviving or reforested tracts are concentrated on inferior types of habitat. Main conclusions Results suggest that the present-day forest patches may not be a proportionate sample of the primeval forest. Rather, they are concentrated on agriculturally-inferior (coarse-textured, steeply-sloped, or poorly-drained) types of habitat. Unless these stands are for some unknown reason compositionally richer than their pre-settlement counterparts, these results suggest that the existing forest resource in southern Lower Michigan is an inferior (biased) sample of the primeval cover. Furthermore, because forest types associated with the most heavily-developed agricultural sites have apparently suffered the most loss of habitat, species more characteristic of these types may have experienced a greater decline in overall importance across the landscape. This study suggests that policy aimed at increasing the potential biodiversity of Land cover disturbance associated with the arrival of European settlers has left the Midwestern United States with a severely altered forest ecosystem The result today is a pattern of altered forest fragments, and plant scientists confront the challenge of determining how and to what degree they resemble the pre-settlement forest. Such a question is significant not only because of academic goals arising out of our need to know about our own environment, but also because conservation policy intended to restore forest biodiversity to pre-settlement levels needs to be informed by solid empirical understanding. Actually, two distinct kinds of questions about the relationship between present and former forests arise, one of which has dominated this area of research. It concerns the composition of the pre-settlement forests and the degree to which present forest remnants resemble them, and approaching it requires inventories not only of present forest resources but also of the prehistoric composition, which necessitates the development of scientific methods that allow us to reliably reconstruct the forests of the past. One way this reconstruction has been attempted is through inference based on fossil pollen deposits. Since the pioneering work of Von Post (1917) and Another way the composition of the historic forests can be estimated is through the use of 'witness trees' from land survey records, following the pioneering work of A second, less-frequently-asked set of questions about the degree of match-up between contemporary forests and their pre-settlement counterparts has to do with the proportion of different forest types across the contemporary landscape vs. the historic condition, and this relationship is the focus of our paper. Questions of this type are relevant to the issue of biodiversity on the total landscape (rather than in particular stands) and arise because evidence suggests that the decisions as to which forests early European settlers removed for agricultural pursuit were systematic rather than random. That is, because some kinds of habitats were (and remain) preferred for farming over others, these kinds were most frequently cleared may also be the last to be abandoned and reforested (as farming in parts of the Midwest has recently declined). From the standpoint of ecological interpretation of present-day forests, such a selective process of clearing would be important if it would affect the degree to which extant forests in aggregate mirror the pre-settlement condition. As intuitive as such an outcome seems, we are aware of no formal scientific treatment of the evidence for such systematic bias in the land-clearing process and/or its impact on the contemporary forest resource. This paper is our attempt to address this deficiency by determining the degree to which the current forest remnants in a portion of the Midwest (southern Lower Michigan) represent the pre-settlement forest, that is, whether they form a proportionate sample of these forests. As Keywords Pre-settlement forest, biodiversity, Michigan P. R. Scull and J. R. Harman 1504 Journal of Biogeography 31, 1503-1514, ÂȘ 2004 Blackwell Publishing Ltd unattractive for farming and the forest composition on those sites. If such a linkage could be established, then the resulting pattern of (both remnant and reforested) woodlots would be distributed non-randomly across all possible sites on a landscape, with a clear preference for agriculturally-inferior sites. We seek to determine whether such a pattern is objectively verifiable on the southern Michigan landscape by determining whether various categories of landscape types support both a larger and smaller proportion of the total forest area today than they did prior to European settlement. We think this question is significant because an answer to it might inform conservation strategies geared to enhancing total landscape (not stand) biodiversity. Obviously, the ideal restored (or preserved) forest resource (in terms of biodiversity) will be the one that most closely approximates the proportion of types present in their pre-settlement distribution. One that either over or under-represents the original mix of types would be an inauthentic reproduction. Unless we know both what proportion of the areal coverage of the original forest consisted of what type and to what degree the present cover is a proportionate sample of the various types in that original, programmes designed to promote the indiscriminate preservation of extant forest stands may end up contributing to the development of a contemporary forest cover skewed quite far from the original in terms of the proportion of its component types. BACKGROUN
Human parainfluenza virus serotypes differ in their kinetics of replication and cytokine secretion in human tracheobronchial airway epithelium
Human parainfluenza viruses (PIVs) cause acute respiratory illness in children, the elderly, and immunocompromised patients. PIV3 is a common cause of bronchiolitis and pneumonia, whereas PIV1 and 2 are frequent causes of upper respiratory tract illness and croup. To assess how PIV1, 2, and 3 differ with regard to replication and induction of type I interferons, interleukin-6, and relevant chemokines, we infected primary human airway epithelium (HAE) cultures from the same tissue donors and examined replication kinetics and cytokine secretion. PIV1 replicated to high titer yet did not induce cytokine secretion until late in infection, while PIV2 replicated less efficiently but induced an early cytokine peak. PIV3 replicated to high titer but induced a slower rise in cytokine secretion. The T cell chemoattractants CXCL10 and CXCL11 were the most abundant chemokines induced. Differences in replication and cytokine secretion might explain some of the differences in PIV serotype-specific pathogenesis and epidemiology
National mitigation potential from natural climate solutions in the tropics.
Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Agreement, confusion persists about the potential contribution of better land stewardship to meeting the Agreement's goal to hold global warming below 2°C. We assess cost-effective tropical country-level potential of natural climate solutions (NCS)-protection, improved management and restoration of ecosystems-to deliver climate mitigation linked with sustainable development goals (SDGs). We identify groups of countries with distinctive NCS portfolios, and we explore factors (governance, financial capacity) influencing the feasibility of unlocking national NCS potential. Cost-effective tropical NCS offers globally significant climate mitigation in the coming decades (6.56 Pg CO2e yr-1 at less than 100 US$ per Mg CO2e). In half of the tropical countries, cost-effective NCS could mitigate over half of national emissions. In more than a quarter of tropical countries, cost-effective NCS potential is greater than national emissions. We identify countries where, with international financing and political will, NCS can cost-effectively deliver the majority of enhanced NDCs while transforming national economies and contributing to SDGs. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'
The design and testing of a dual fiber textile matrix for accelerating surface hemostasis
The standard treatment for severe traumatic injury is frequently compression and application of gauze dressing to the site of hemorrhage. However, while able to rapidly absorb pools of shed blood, gauze fails to provide strong surface (topical) hemostasis. The result can be excess hemorrhage-related morbidity and mortality. We hypothesized that cost-effective materials (based on widespread availability of bulk fibers for other commercial uses) could be designed based on fundamental hemostatic principles to partially emulate the wicking properties of gauze while concurrently stimulating superior hemostasis. A panel of readily available textile fibers was screened for the ability to activate platelets and the intrinsic coagulation cascade in vitro. Type E continuous filament glass and a specialty rayon fiber were identified from the material panel as accelerators of hemostatic reactions and were custom woven to produce a dual fiber textile bandage. The glass component strongly activated platelets while the specialty rayon agglutinated red blood cells. In comparison with gauze in vitro, the dual fiber textile significantly enhanced the rate of thrombin generation, clot generation as measured by thromboelastography, adhesive protein adsorption and cellular attachment and activation. These results indicate that hemostatic textiles can be designed that mimic gauze in form but surpass gauze in ability to accelerate hemostatic reactions
Digital Soil Mapping: Approaches to Integrate Sensing Techniques to the Prediction of Key Soil Properties
Simultaneous measurement and modulation of multiple physiological parameters in the isolated heart using optical techniques
GEOG 245
Geography is defined traditionally as a discipline concerned with the spatial distribution and interactions of physical and societal processes. This theme is shared by all geographers and is reflected by the issues in which geographers engage. Although Geography may seem eclectic at first glance, its diversity and commonality combine in a powerful mix of knowledge, theory, and methodology well suited to address many of todayâs complex social and environmental problems. Rapid advances in information technology over the past decade have made it possible to ask new sets of questions and address problems in new and exciting ways. Most important for geographers has been the development of computerized geographic information systems (GIS)
GEOG 321
The objective of GEOG231 is to provide students with a general understanding of the processes and spatial distribution of the Earth\u27s primary physical systems and the ways in which humans interact with these systems. Course emphasis is divided into three areas: the energy â atmosphere system, waterweather and climate systems, and the earth â atmosphere interface. Students are introduced to the basic physical processes and interactions that operate within each of these categories, with special focus on the ways in which these factors relate to contemporary environmental problems. GEOG 231 serves as an excellent starting point for the wide variety of environmental courses offered at Colgate. Students who successfully complete this seminar will satisfy one half of their Natural Sciences and Mathematics area of inquiry requirement
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