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A strategy to assess river restoration success 总被引:6,自引:0,他引:6
SHARON WOOLSEY FLORENCE CAPELLI TOM GONSER EDUARD HOEHN MARKUS HOSTMANN BERIT JUNKER ACHIM PAETZOLD CHRISTIAN ROULIER STEFFEN SCHWEIZER SCOTT D. TIEGS KLEMENT TOCKNER CHRISTINE WEBER ARMIN PETER 《Freshwater Biology》2007,52(4):752-769
1. Elaborate restoration attempts are underway worldwide to return human‐impacted rivers to more natural conditions. Assessing the outcome of river restoration projects is vital for adaptive management, evaluating project efficiency, optimising future programmes and gaining public acceptance. An important reason why assessment is often omitted is lack of appropriate guidelines. 2. Here we present guidelines for assessing river restoration success. They are based on a total of 49 indicators and 13 specific objectives elaborated for the restoration of low‐ to mid‐order rivers in Switzerland. Most of these objectives relate to ecological attributes of rivers, but socio‐economic aspects are also considered. 3. A strategy is proposed according to which a set of indicators is selected from the total of 49 indicators to ensure that indicators match restoration objectives and measures, and that the required effort for survey and analysis of indicators is appropriate to the project budget. 4. Indicator values are determined according to methods described in detailed method sheets. Restoration success is evaluated by comparing indicator values before and after restoration measures have been undertaken. To this end, values are first standardised on a dimensionless scale ranging from 0 to 1, then averaged across different indicators for a given project objective, and finally assigned to one of five overall success categories. 5. To illustrate the application of this scheme, a case study on the Thur River, Switzerland, is presented. Seven indicators were selected to meet a total of five project objectives. The project was successful in achieving ‘provision of high recreational value’, ‘lateral connectivity’ and ‘vertical connectivity’ but failed to meet the objectives ‘morphological and hydraulic variability’ and ‘near natural abundance and diversity of fauna’. Results from this assessment allowed us to identify potential deficits and gaps in the restoration project. To gain information on the sensitivity of the assessment scheme would require a set of complementary indicators for each restoration objective. 相似文献
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DENIS BARABÉ CHRISTIAN LACROIX MATHIEU CHOUTEAU MARC GIBERNAU 《Botanical journal of the Linnean Society. Linnean Society of London》2004,146(2):181-190
This study presents a survey of the species of the Araceae where extracellular production of calcium oxalate crystals has been observed and discusses the patterns of production of the crystals in different genera. For all Araceae studied using SEM, the oxalate crystals exuding on the epidermal surface correspond to extended aggregate/druses or crystal sand and the oxalate crystals mixed with pollen correspond to raphides or styloids (prismatic crystals). The type of crystals associated with pollen varies among genera. However, the presence of crystals associated with pollen is a specific rather than a generic characteristic. Our results show that the presence of raphides mixed with pollen seems to be a widespread phenomenon in the aroid family. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 181–190. 相似文献
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CHRISTIAN C. EMIG 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1981,14(2):151-156
Some traditional concepts on lingulid paleoecology are reviewed and discussed in regard to new data on the ecology of Recent lingulid brachiopods. Fossilization in life-position occurs under several ecological conditions, e.g. dessication or emersion of the substratum, prolonged increase in salinity, perhaps very rapid sedimentation, extreme changes in temperature, and fossilization of flat-lying shells occurs under prolonged reduction in salinity, storms, natural death. Catastrophic environmental changes cause the fossilization of lingulids. Such events may affect one or more ecological features which may have a direct or indirect effect on the lingulid biology. At this time, the biotype does not correspond to the habitual one, and the survival and behavior of the lingulids depend on the severity of the environmental changes and on the tolerance of the animals to the latter. 相似文献
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CHRISTIAN C. EMIG 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1984,17(2):115-123
Log-probability curves of grain-size distribution have been analysed of sediments collected in three previously described localities occupied by either Lingula anatina or L. reevei (Brachiopoda, Inarticulata). The grain-size population transported by saltation (average about 92–223 μm), generally associated with traction load population, determines Lingula distribution. The two preferential substrates of both studied species (density > 100 individuals/m-2 ) are compact and stable sediments under moderate water currents: either coarse sands and gravels clogged by fine and very fine sands, or fine, very fine and clay sands (saltation populations more than 60%). As soon as the suspension population and/or traction increase in the sediment to the detriment of the saltation population, the density of Lingula decreases rapidly. Nevertheless, if grain-size distribution and populations have a primordial function for Lingula , other ecological features (i.e. the environmental fauna, high occurrence of digging species, the available nutrients) will affect the distribution and sometimes become prevailing. The absence of important changes in the shell shape of Lingula since its origin suggests that the grain-size requirements remained about the same. 相似文献
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CHRISTIAN PETER KLINGENBERG 《Biological reviews of the Cambridge Philosophical Society》1998,73(1):79-123
The connection between development and evolution has become the focus of an increasing amount of research in recent years, and heterochrony has long been a key concept in this relation. Heterochrony is defined as evolutionary change in rates and timing of developmental processes; the dimension of time is therefore an essential part in studies of heterochrony. Over the past two decades, evolutionary biologists have used several methodological frameworks to analyse heterochrony, which differ substantially in the way they characterize evolutionary changes in ontogenies and in the resulting classification, although they mostly use the same terms. This review examines how these methods compare ancestral and descendant ontogenies, emphasizing their differences and the potential for contradictory results from analyses using different frameworks. One of the two principal methods uses a clock as a graphical display for comparisons of size, shape and age at a particular ontogenic stage, whereas the other characterizes a developmental process by its time of onset, rate, and time of cessation. The literature on human heterochrony provides particularly clear examples of how these differences produce apparent contradictions when applied to the same problem. Developmental biologists recently have extended the concept of heterochrony to the earliest stages of development and have applied it at the cellular and molecular scale. This extension brought considerations of developmental mechanisms and genetics into the study of heterochrony, which previously was based primarily on phenomenological characterizations of morphological change in ontogeny. Allometry is the pattern of covariation among several morphological traits or between measures of size and shape; unlike heterochrony, allometry does not deal with time explicitly. Two main approaches to the study of allometry are distinguished, which differ in the way they characterize organismal form. One approach defines shape as proportions among measurements, based on considerations of geometric similarity, whereas the other focuses on the covariation among measurements in ontogeny and evolution. Both are related conceptually and through the use of similar algebra. In addition, there are close connections between heterochrony and changes in allometric growth trajectories, although there is no one-to-one correspondence. These relationships and outline links between different analytical frameworks are discussed. 相似文献