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21.
Will Allen Ockie Bosch Margaret Kilvington Don Harley and Ian Brown 《Natural resources forum》2001,25(3):225-233
Adaptive, or 'learning by doing', approaches are often advocated as a means of providing increased understanding within natural resource management. However, a number of organisational and social issues need to be resolved if these approaches are to be used successfully. A case study in the South Island high country of New Zealand is used to review what is needed to support an ongoing community-based monitoring and adaptive management programme. First, the case study is described, paying attention to the social context of the resource management problem. The results of a workshop that explored this problem are then outlined, along with a proposed information flow suggested by participants. Requirements for future steps to resolve these problems (such as information protocols and a multi-stakeholder information system) are discussed. Finally, some broad lessons are drawn from this exercise that could help others developing similar approaches. 相似文献
22.
Magne Friberg Namphung Vongvanich Anna-Karin Borg-Karlson Darrell J Kemp Sami Merilaita Christer Wiklund 《Behavioral ecology and sociobiology》2008,62(6):873-886
Animal courtship rituals are important for species recognition, and a variety of cues might be utilized to recognize conspecific
mates. In this paper, we investigate different species-recognition mechanisms between two sympatric butterfly sister species:
the wood white (Leptidea sinapis) and Real’s wood white (Leptidea reali). We show that males of both species frequently court heterospecific females both under laboratory and field conditions.
The long-lasting elaborate courtships impose energetic costs, since the second courtship of males that were introduced to
two subsequent conspecific females lasted on average only one fourth as long as the first courtship. In this paper, we demonstrate
that premating reproductive isolation is dependent on female unwillingness to accept heterospecific mates. We studied female
and male courtship behavior, chemical signaling, and the morphology of the sexually dimorphic antennae, one of the few male
traits visible for females during courtship. We found no differences in ultraviolet (UV) reflectance and only small differences
in longer wavelengths and brightness, significant between-species differences, but strongly overlapping distributions of male
L. sinapis and L. reali antennal morphology and chemical signals and minor differences in courtship behavior. The lack of clear-cut between-species
differences further explains the lack of male species recognition, and the overall similarity might have caused the long-lasting
elaborate courtships, if females need prolonged male courtships to distinguish between con- and heterospecific suitors. 相似文献
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Population structure and energetics of the shallow-water antarctic sea star Odontaster validus in contrasting habitats 总被引:4,自引:0,他引:4
Individuals and populations of Odontaster validus Koehler differed markedly among different habitats, as revealed in a study from October 1984 through January 1986 in McMurdo Sound, Antarctica. At McMurdo Station, individual sizes (wet weight) and population biomass (g wet wt m-2 and kJ m-2) decreased significantly with increasing depth. Individuals from shallow (10 to 20 m) habitats were in superior nutritional condition to those from deeper water (30 and 165 m), as shown by higher gonad and pyloric cecum indexes, and by higher lipid and energetic levels in the pyloric ceca. Moreover, gonadal output (reproductive output) was higher in shallow-water individuals. Higher levels of chlorophyll in the pyloric ceca and richer yellow to red coloration of the body wall in the shallow-water individuals indicate that they utilize the higher levels of primary production at shallow depths. At East Cape Armitage, where nearly permanent, thick, snow-covered ice most of the year resulted in very low levels of benthic primary production, the lowdensity sea stars were all very small and nutritionally similar to the deep-water individuals at McMurdo Station. At Cape Evans, where the generally snow-free sea-ice that broke up in mid-summer resulted in a luxurient benthic cover of diatoms and macroalgae, the sea stars were smaller than at McMurdo Station at comparable depths, but population densities were higher, resulting in 4 to 9 times greater biomass. Growth rates of sea stars fed in the laboratory were very low, especially compared to laboratory-reared temperate and tropical species; well-fed individuals need about 9 yr to reach 30 g wet weight, near the mean size of shallowwater individuals at McMurdo Station. No growth was detected in individuals caged at McMurdo Station for one year, suggesting even lower growth rates in the field. The stable size-frequency distributions at the different sites and depths throughout the year-long study suggest highly stable populations with low temporal variability in recruitment, migration and mortality. These data indicate that individuals and populations of O. validus quantitatively and qualitatively reflect the general level of productivity of a habitat. Differences noted in size, coloration, nutrition, and reproductive effort may be the result of long-term integration of local levels of primary production. These ubiquitous sea stars may serve as a biotic indicator of productivity in localized habitats around the continental shelf of Antarctica. 相似文献
26.
Fisher's theory of sex allocation predicts that, in a panmictic population, parental investment will be equally distributed between male and female progeny. Most studies on parental investment in nesting solitary bees and wasps use offspring or provision weight as estimators of parental investment and do not corroborate Fisher's theory. The measurement of parental investment may be confounded by several factors. First, the use of offspring or provision size does not account for seasonal variation in foraging costs associated with aging of nesting females. Second, provision or offspring size do not reflect parental investment associated with nest construction. In this two-year study we measured parental investment in a solitary bee. We calculated sex allocation using both provision weight and foraging time as parental investment estimators. Investment in pollen-nectar provisions decreased, while investment in mud structures (nest construction) increased, as the nesting period progressed. Overall investment in provisions per nest was ∼25 times higher than investment in mud. Pollen-nectar foraging trips became longer as the season progressed, but mud trip duration did not vary. Due to weather differences between years, more offspring per female were produced in the first year, but progeny sex ratio and mean offspring size of both sexes were similar between years. Mortality did not differ between sexes. As predicted by Fisher's theory, production cost ratios did not differ from 1 in either year, irrespective of the currency used to estimate parental investment (provision weight or foraging time). Our results strongly support Fisher's theory. 相似文献
27.
Although contemporary animal contest theory emphasises the importance of physical asymmetries in resolving disputes, such
asymmetries do not obviously settle fights in all groups. Territorial male butterflies, for example, compete via elaborate
non-contact aerial interactions in which success is determined by relative persistence. Prior research suggests that the resolution
of these contests is not clearly related to physical variables such as body size or energy reserves. However, given that the
contests involve elaborate aerial manoeuvres, one long-standing suggestion is that asymmetries in flight performance, and
thus flight morphology, may be important. We addressed this hypothesis via a manipulative investigation into the biophysical
correlates of contest success in the speckled wood butterfly, Pararge aegeria. This species possesses the ability for significant adaptive phenotypic plasticity in relevant flight morphological parameters.
We took advantage of this plasticity to rear 90 individuals of markedly varying flight morphologies, which we then pitted
against each other in a semi-controlled experimental fashion. Multiple logistic and lognormal analyses provided little evidence
for the relevance of morphological parameters, including relative flight musculature, wing loading and wing aspect ratio (wing
length relative to area), to the outcome and/or duration of experimental contests. Instead, we found a positive effect of
age upon contest success. Given that ability for high acceleration is strongly linked to variation in these morphological
parameters, our findings suggest that flight performance is not a strong determinant of resource-holding potential in this
notably territorial butterfly. 相似文献
28.
Clones of cultivated amniotic fluid cells that have distinct morphologic and growth characteristics (F, AF and E-type) were examined by one-dimensional SDS polyacrylamide gel electrophoresis (SDS-PAGE) and by two-dimensional electrophoresis employing isoelectric focusing and SDS-PAGE (IEF-PAGE). No qualitative differences in band pattern were observed in SDS-PAGE between the various amniotic fluid cell types, but consistent quantitative differences in the ratios of four bands of presumed filamentous proteins provided good distinction between amniotic fluid cells and postnatal skin fibroblast-like cells. By adding separation on the basis of electrical charge to that of molecular size (IEF-PAGE), we observed reproducible qualitative differences in the protein spot patterns between F and both AF and E-type amniotic fluid cells. At least eight discrete proteins appear not to be synthesized by prenatal F-type cells in comparison with their isogenic AF and E counterparts under identical culture conditions. The two-dimensional electrophoretic patterns thus confirm that F and AF amniotic cells, in spite of their morphologic and growth kinetic similarities, are developmentally distinct cell types that retain their differentiated states in culture. 相似文献
29.
Katrin Bieger Jeffrey G. Arnold Hendrik Rathjens Michael J. White David D. Bosch Peter M. Allen 《Journal of the American Water Resources Association》2019,55(3):578-590
In recent years, watershed modelers have put increasing emphasis on capturing the interaction of landscape hydrologic processes instead of focusing on streamflow at the watershed outlet alone. Understanding the hydrologic connectivity between landscape elements is important to explain the hydrologic response of a watershed to rainfall events. The Soil and Water Assessment Tool+ (SWAT+) is a new version of SWAT with improved runoff routing capabilities. Subbasins may be divided into landscape units (LSUs), e.g., upland areas and floodplains, and flow can be routed between these LSUs. We ran three scenarios representing different extents of connectivity between uplands, floodplains, and streams. In the first and second scenarios, the ratio of channelized flow from the upland to the stream and sheet flow from the upland to the floodplain was 70/30 and 30/70, respectively, for all upland/floodplain pairs. In the third scenario, the ratio was calculated for each upland/floodplain pair based on the upland/floodplain area ratio. Results indicate differences in streamflow were small, but the relative importance of flow components and upland areas and floodplains as sources of surface runoff changed. Also, the soil moisture in the floodplains was impacted. The third scenario was found to provide more realistic results than the other two. A realistic representation of connectivity in watershed models has important implications for the identification of pollution sources and sinks. 相似文献
30.