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111.
Integrating conservation and development: incorporating vulnerability into biodiversity-assessment of areas 总被引:3,自引:0,他引:3
Protection of regional biodiversity requires that priority for protection of individual areas be based on both the contribution the area can make to representing overall biodiversity and the degree to which the area, in the absence of action, is vulnerable to loss of its biodiversity. Attempts to apply these criteria together largely have been ad hoc. A solution to this problem is presented for environmental surrogate data, based on environmental diversity (ED). ED uses a standard ecological continuum model to link environmental pattern to species-level biodiversity, so that a set of areas can be characterized by its relative expected biodiversity. This allows explicit incorporation of estimates of area-vulnerability, interpreted as the relative probability that any member species will not persist, into biodiversity assessments. The contribution of a given area to regional expected biodiversity is influenced not only by its own vulnerability value, but also by the vulnerability of other areas. Increasing the degree of protection of any area (reducing its vulnerability) will increase expected biodiversity: however, expected regional biodiversity sometimes may be maximized when limited resources for protection are directed to an area with lower vulnerability rather than to one with higher vulnerability.The allocation of land uses in a region need not be viewed as an all-or-nothing assignment of protection. The effect of a particular management regime on the biodiversity of a given area can be equated with some consequent degree of vulnerability; viewed positively, a management regime that offers some degree of biodiversity protection can make a measurable contribution to the protection of the biodiversity of a region. 相似文献
112.
本文系统地回顾了日本志留纪至三叠纪牙形刺研究的历史和现在的成果。志留纪牙形刺只有少数零星的报道,没有建立化石带;早泥盆世已建立了5个牙形刺组合,没有中、晚泥盆世的记录;石炭纪有8个牙形刺带,其中晚石炭世3个牙形刺带;二叠纪5个牙形刺带或动物群,其中,中、晚二叠世各1个带(动物群);三叠纪可划分出14个牙形刺带。 相似文献
113.
第四纪甲虫的研究在国外已开展多年,形成了一套完整的方法,而在我国几乎为一空白。第四纪甲虫研究方法一般包括如下几个步骤:野外采样,实验室分离,标本保存,标本鉴定,结果分析。第四纪甲虫研究的意义主要表现在如下三个方面:重建古气候、恢复昆虫地理史和第四纪考古。 相似文献
114.
Joachim Messing 《Molecular biotechnology》1996,5(1):39-47
DNA sequence and expression analyses have greatly benefited from using M13 and pUC derived cloning vectors and their polycloning
sites. A chronology of the original concepts and experiments is reviewed. 相似文献
115.
The populations of the urodele Salamandra salamandra in the Northern Iberian Peninsula exhibit very different coloration patterns and a remarkable range in reproductive modes (from giving birth to a large number of aquatic larvae to a parturition event of just a few fully metamorphosed, i.e. terrestrial, offspring). Electrophoretic study of geographic variation in allozymes shows that this extraordinary diversity, particularly in reproductive modes, is not accompanied by a genetic differentiation of similar magnitude. All the populations sampled along a transect crossing the Northern part of the Iberian Peninsula and encompassing the various reproductive strategies, as previously described, can be ascribed to a single species, because of small interpopulational genetic distances (ranging DNei from 0.05 to 0.199) and absence of fixed (diagnostic) alleles. A variety of phenetic and cladistic methods were used to elucidate the relationship among populations, based on allozyme data. These methods defined two well corroborated clusters: the first contains populations of salamanders with a blotched dorsal coloration pattern and characterized by parturition of aquatic larvae; the second group is composed of populations exhibiting a striped dorsal coloration pattern, smaller adult body size, and giving birth to fully metamorphosed terrestrial offspring. The latter group also encompasses some populations where mixed parturition events, which include both larvae and metamorphosed offspring, which have been recorded (Dopazo and Alberch, 1994). The absence of a correlation between genetic and geographic distance suggests that the mode of differentiation of the species is based on at least two successive events of isolation, radiation, and secondary contact between populations. Furthermore, the validity of the described “subspecies” is questioned by our data, which point out the need for a detailed systematic study of Salamandra from a global perspective. “Viviparity”, here meaning giving birth to fully metamorphosed offspring, originated once and occurs as intraspecific, and even as intrapopulational variation. Thus, we confirm a system where a major evolutionary innovation -the acquisition of independence from the aquatic media in the primitive amphibian complex life cycle-, can be studied at the microevolutionary, i.e., intra- and inter-populational level. 相似文献
116.
117.
Kazuhiro Kogame 《Phycological Research》1996,44(2):85-94
Morphology of field material and life history in culture were studied in Scytosiphon canaliculatus (Setchell et Gardner) comb. nov. from northern Japan. Erect gametophytes of S. canaliculatus are cylindrical, tubular, up to 7 mm wide and 40 cm long, and without regular constrictions. S. canaliculatus has pronounced anisogamy and ascocysts accompanied with plurilocular gametangia. The life history of S. canaliculatus showed an alternation between erect gametophytes and crustose prostrate sporophytes bearing unilocular sporangia. Since field sporophytes of S. canaliculatus were found to be identical with Hapterophycus canaliculatus Setchell et Gardner (Ralfsiaceae, Phaeophyceae), it is proposed to transfer H. canaliculatus to the genus Scytosiphon. In the field, gametophytes with plurilocular gametangia appeared in spring and disappeared in summer. Sporophytes with unilocular sporangia were collected in late autumn and winter. Unilocular sporangia were produced at 15°C in short-day culture conditions and unispores developed into erect gametophytes at 5–15°C. It is suggested that the seasonal Occurrence of gametophytes in the field is due to the seasonal formation of unilocular sporangia, which is regulated by temperature and photoperiod. 相似文献
118.
Klaus Hövemeyer 《Oecologia》1995,102(1):86-94
The food web centering on Allium ursinum (Liliaceae) in a beech forest (Germany) is described, and temporal variation of active trophic links is related to species' life cycles. The most important insect herbivores are Cheilosia fasciata (a larval leaf miner) and Portevinia maculata (a larva bulb miner) (Diptera: Syrphidae). Energy, carbon and nitrogen flow in the food chain (Allium-Cheilosia-Phygadeuon ursini) are investigated and analysed with respect to differences in resource allocation by the leaf miner and its hymenoptereous parasitoid. In C. fasciata nitrogen is likely to be the limiting resource, while growth in Phygadeuon ursini appears energy-limited. Larval feeding habits of C. fasciata and Portevinia maculata determined the timing of the species' life cycles and, as a consequence, appeared to preclude the existence of a pupal parasitoid in Portevinia maculata. Further details of life history traits are demonstrated and discussed. 相似文献
119.
Patricia C. Wright 《International journal of primatology》1995,16(5):835-854
I conducted the first long- term study of the life history patterns of Propithecus diadema edwardsi—Milne- Edward’s sifaka— in the rain forests of southeastern Madagascar, beginning in 1986. I report behavioral observations
on a total of 33 individuals from three groups over a 9- year span. We captured,marked, and released 21 individuals. Individual group size ranged from three to nine sifakas. Two breeding females lived in
groups I and II until 1993. A newly formed group (III) had one breeding female. Age at first reproduction is 4 years for females
and 5 years for males. Gestation length is 179 days (n =2). Most births occurred in June (n = 17), but infants were also born in May (n = 2) and July (n =2). Nine of 21 (43%) infants born died before the age of 1 year, and 15 (67%) died before the age of reproduction. One female
bred in her natal group after the death of the resident male and the immigration of an adult male. Another two females disappeared
at 4 and 5 years of age;they could have emigrated or died. All 5- to- 6- year- old males (n = 4) have emigrated from their natal groups to adjacent
groups. Two have committed infanticide. Five or more individuals were killed by Cryptoprocta ferox.Despite high mortality and offspring dispersal, the number of individuals in the two main groups remained nearly the same
over the 9- year study. 相似文献
120.
M. J. van Steenis K. A. M. H. El-Khawass 《Entomologia Experimentalis et Applicata》1995,76(2):121-131
Life table data forAphis gossypii Glover (Homoptera: Aphididae), an important pest in glasshouse cucumber crops, were studied at 20, 25 and 30°C on two cucumber
cultivars (Cucumis sativus L.) in controlled climate cabinets. The development time on the cucumber cv. ‘Sporu’ ranged from 4.8 days at 20°C to 3.2
days at 30°C. Immature mortality was approximately 20% and did not differ between temperatures. Most mortality occurred during
the first instar. Reproduction periods did not differ among temperatures, but at 25 and 30°C more nymphs were produced (65.9
and 69.8 nymphs/♀, respectively) than at 20°C (59,9 nymphs/♀) because of a higher daily reproduction. Intrinsic rate of increase
was greatest at 25°C (r
m
=0.556 day−1). At 20 and 30°C the intrinsic rate of increase was 0.426 and 0.510, respectively. On cv. ‘Aramon’, the development time
ofA. gossypii was approximately 20% longer at all temperatures. Immature mortality did not differ between the two cultivars. The intrinsic
rate of increase on cv. ‘Aramon’ was 15% smaller than on cv. ‘Sporu’. The use of cucumber cultivars partially resistant to
aphids is discussed in relation to biological control of cotton aphid in glasshouses. Development time and immature mortality
on leaves of the middle and upper leaf layer of glasshouse grown cucumber plants (cv. ‘Aramon’) were comparable to development
in the controlled climate cabinets. On the lower leaves immature mortality was much higher (approximately 82%) than on leaves
of the middle (24.0%) and upper leaf layer (24.5%). Reproduction was less on the lower leaf layer (45.9, 70.5 and 70.1 nymphs/♀
on leaves of the lower, middle and upper leaf layer, respectively).
Aphids, successfully parasitized byAphidius colemani Viereck (Hymenoptera: Braconidae) only reproduced when they were parasitized after the third instar. Fecundity was 0.1 to
0.9 and 10.5 to 13.3 nymphs/♀ for aphids parasitized in the fourth instar or as adults, respectively. Reproduction of aphids
that were stung but survived the attack was lower than for aphids not stung. Average longevity of these aphids was equal to
the longevity of aphids not stung byA. colemani. 相似文献