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131.
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133.
sustainability, but the most meaningful definition is set within an evolutionary framework. Mechanistic and evolutionary frameworks for sustainable
development are discussed. Evolution and adaptation are characteristics of complex adaptive systems, and a new understanding
of sustainable development can be gleaned by using the complex adaptive systems framework. This approach to sustainable development
issues implicitly requires proactive involvement by the public. This paper supports that bottom-up participation needs to
be nurtured. Appropriate processes to enable participation need to be designed and implemented. 相似文献
134.
J. B. Graham 《Marine Biology》1973,23(1):83-91
The physiological adaptations for terrestrial life of the rockskipper Mnierpes macrocephalus (Günther) have been examined and compared with other amphibious species. The rockskipper lives on steep rocky shores in the eastern tropical Pacific Ocean, and makes brief terrestrial excursions for orientation, feeding, and to avoid wave action and predators. The rockskipper spends a large portion of its time, and can live perfectly well, submerged in water. The duration of this species' daytime terrestrial sojourns rarely exceeds 30 min. While on land, the rockskipper respires aerially, through its gills and skin, at the same rate it normally respires in water. When exposed to sunlight without water, the rockskipper's body temperature increases rapidly. A small amount of water, however, enables the rockskipper to remain cool, apparently by dissipating absorbed heat through evaporative cooling of the gills and skin. Evaporative water-loss from respiratory surfaces is a major factor limiting terrestrial excursions of the rockskipper. 相似文献
135.
136.
Foraging areas of king penguins from Macquarie Island in relation to a marine protected area 总被引:1,自引:0,他引:1
Twenty-three king penguins (Aptenodytes patagonicus) from Macquarie Island were tracked by satellite during the late incubation period in 1998–1999 to determine the overlap
of the foraging zone of king penguins with an area to be declared a marine protected area (MPA) near the island. While all
penguins left the colony in an easterly direction and traveled clockwise back to the island, three penguins foraged in the
northern parts of the general foraging area and stayed north of 56°S. The remaining 20 penguins ventured south and most crossed
59°S before returning to the island. The total foraging area was estimated to be 156,000 km2 with 36,500 km2 being most important (where penguins spent >150 hr in total). North-foraging penguins reached on average 331 ± 24 km from
the colony compared to 530 ± 76 km for the south-foraging penguins. The latter traveled an average total distance of 1313
± 176 km, while the northern foragers averaged 963 ± 166 km. Not only did the penguins spend the majority of their foraging
time within the boundaries of the proposed MPA, they also foraged chiefly within the boundaries of a highly protected zone.
Thus, the MPA is likely to encompass the foraging zone of king penguins, at least during incubation. 相似文献
137.
The determination of reproductive status and the reconstruction of individual reproductive histories are central to many ecological
studies. In cetaceans, it has been assumed that ovarian scars accumulate with age and provide a lifetime record of female
reproductive history. If ovarian scars persist, the number of scars should increase with age after puberty. To test this,
we examined age, reproductive status and ovarian scars from 187 short-beaked common dolphins (Delphinus delphis) from the eastern North Atlantic. The number of Corpus Albicans (CA) present in ovaries did not increase with age after age
at sexual maturity (ASM), suggesting that ovarian scars are not persistent and that their number at any one time would be
a function of rates of ovulation and healing, the latter being defined here as the resorption or disintegration of CA tissue.
Since female mammals stop ovulating when pregnant, inferences about healing rates could be made by using pregnant females.
Pregnant females had ca. 40% fewer scars than non-pregnant females. This suggests that most CAs would heal quickly, with a
half-life of less than 1 year, although larger scars may persist longer. Therefore, counting CAs would have limited potential
for reconstructing individual reproductive lifetime histories in the common dolphin. A reassessment of the use of ovarian
scars to reconstruct individual life reproductive histories in cetaceans is suggested. 相似文献
138.
Increasing pressures on ecosystems through global climate and other land-use changes require predictive models of their consequences for vital processes such as soil carbon and nitrogen cycling. These environmental changes will undoubtedly affect soil fauna. There is sufficient evidence that soil fauna have significant effects on all of the pools and fluxes in these cycles, and soil fauna mineralize more N than microbes in some habitats. It is therefore essential that their role in the C and N cycle be understood. Here we introduce a new framework that attempts to reconcile our current understanding of the role of soil fauna within the C and N cycle with biogeochemical models and soil food web models. Using a simple stoichiometric approach to integrate our understanding of N mineralization and immobilization with the C:N ratio of substrates and faunal life history characteristics, as used in food web studies, we consider two mechanisms through which soil fauna can directly affect N cycling. First, fauna that are efficient assimilators of C and that have prey with similar C:N ratios as themselves, are likely to contribute directly to the mineral N pool. Second, fauna that are inefficient assimilators of C and that have prey with higher C:N ratios than themselves are likely to contribute most to the dissolved organic matter (DOM) pool. Different groups of fauna are likely to contribute to these two pathways. Protists and bacteria-feeding nematodes are more likely to be important for N mineralization through grazing on microbial biomass, while the effects of enchytraeids and fungal-feeding microarthropods are most likely to be important for DOM production. The model is consistent with experimental evidence and, despite its simplicity, provides a new framework in which the effects of soil fauna on pools and fluxes can be understood. Further, the model highlights our gaps in knowledge, not only for effects of soil fauna on processes, but also for understanding of the soil C and N cycle in general. 相似文献
139.
H. Manjari Jayathilake Graham W. Prescott L. Roman Carrasco Madhu Rao William S. Symes 《Ambio》2021,50(1):215
Analysing the drivers of deforestation and forest degradation in conservation landscapes can provide crucial information for conservation management. While rates of forest loss can be measured through remote sensing, on the ground information is needed to confirm the commodities and actors behind deforestation. We administered a questionnaire to Wildlife Conservation Society’s landscape managers to assess the deforestation drivers in 28 tropical conservation landscapes. Commercial and subsistence agriculture were the main drivers of deforestation, followed by settlement expansion and infrastructure development. Rice, rubber, cassava and maize were the crops most frequently cited as drivers of deforestation in these emblematic conservation landscapes. Landscape managers expected deforestation trends to continue at similar or greater magnitude in the future, calling for urgent measures to mitigate these trends.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01325-9) contains supplementary material, which is available to authorized users. 相似文献
140.