植物种群资源竞争与共存的理论模型研究   总被引：1，自引：0，他引：1  

王锋刚  曾晓东 《气候与环境研究》2015,20(2):229-234

自然生态系统不同植物种群之间存在着广泛的竞争,且多种植物种群可以共存,即具有生物多样性。经典的资源竞争模型(莫诺模型)支持生态学上的"竞争排斥原理",不适用于阐释自然生态系统不同植物种群间的竞争与共存。根据植物生态系统的特点,引入植物种群的生长率随着物种个体大小/个体数增加而逐渐趋于饱和的性质,建立自抑制资源竞争模型。该模型与莫诺模型的本质区别在于,物种的临界可利用资源随种群密度增加而上升,从而可以达到不同物种间的平衡。数学分析及数值模拟结果表明,该模型可允许多物种稳定共存(即共存的物种种类数可以多于供给其生长的资源种类数),同时优势物种随资源供给率增加而依次变化。  相似文献   

The invasion of the intertidal canopy-forming alga Fucus serratus L. to southwestern Iceland: Possible community effects     

Agnar Ingólfsson 《Estuarine, Coastal and Shelf Science》2008

The intertidal serrated wrack, Fucus serratus L. (Fucales: Phaeophyceae), has become an abundant canopy-forming alga along a ca. 100 km stretch of shore in southwestern Iceland in the last century. Its distribution has not changed noticeably since a survey in 1975/1976. Many experimental studies have shown that canopy-forming algae can have profound effects on the community structure. Although such experiments involving F. serratus are few it was decided to test predictions from these experiments on a geographical scale by comparing community compositions within the area where F. serratus is a dominant algae (since at least 1975/1976) with an adjacent area of similar size where F. serratus is absent (with a single exception without consequences). The work is based on measurements on some 372 stations in the F. serratus area, termed region A, and 227 stations from the F. serratus-free area, termed region B. Percentage cover of algae and sessile invertebrates was estimated on 2 m² on each station and animals collected from 800 cm² from each station. The vertical distribution of F. serratus was most similar to that of Fucus distichus and the two species often grew intermingled on the lower part of the shore. F. serratus appeared to have reduced the cover of F. distichus in the lowermost part of the shore, while having little or no effect on other canopy-forming species. The low abundance of Semibalanus balanoides in the F. serratus area (region A) is in line with experiments showing detrimental effect on this barnacle by whiplash of F. serratus. In general algal grazers were more abundant in region A, consistent with the greater attractiveness of F. serratus than other canopy-forming species to grazers, although this may be partly explained by the abundance of understorey algae in region A.  相似文献   

当前遥感技术发展及产业化分析     

景贵飞 《地理信息世界》2007,5(3):6-16,23

目前,我国遥感技术的研究发展和产业化面临着巨大的需求和发展机遇,完善遥感技术体系的建设,实践科技发展三大战略,规范和提高遥感产品生产能力,将遥感技术发展成为一项工业,是遥感技术顺应新时代的战略选择。本文基于产业经济学原理和遥感技术本身特点,对遥感产业化提出了技术发展、产业化和市场竞争政策的建议。  相似文献   

Habitat Selection and Space Partitioning among two Mediterranean Blenniid Species   总被引：4，自引：0，他引：4  

Veronika H.  Koppel 《Marine Ecology》1988,9(4):329-346

Abstract. The utilization of the spatial resources of two syntopic blenniid species - Blennius cunevue and Blennius incognitas - has been investigated in silu and under laboratory conditions. Both species occupy bore holes of the mussel Lithophugu in the sublittoral zone. B. cunevue dominates the more shallow zone (= 0.68 m) and prefers smaller (= 12.76 mm diameter) and horizontal bore holes. B. incognitus inhabits the same depth range as B. cunevue but occupies larger bore holes (= 14.57 mm) in a deeper zone (= 0.86 m). Individuals of B. incognitus do not prefer a special inclination angle. The two blenniid species defend territories with different intraspecific sizes: the mean territory radius of B. cunevue is 6.87 mm, of B. incognitus = 10.95. Mechanisms to reduce competition include different activity rhythm, interspecific social dominance, and differences in territoriality. B. cunevue is the dominant species; its territories arc defended against conspecifics and against B. incognitus.  相似文献   

Polymorphic Zooids in Deitaic Species Populations of Conopeum seurati (CANU, 1928) (Bryozoa, Cheilostomata)     

Angelo  Poluzzi Bruno  Sabelli 《Marine Ecology》1985,6(3):265-284

Abstract. Deltaic populations of Conopeum seurati from diverse environmental settings have variable phenotypes related to strong competitive regimes and to dissolved oxygen minima. Under extremely stressful conditions, the poorly canalized phenotype of C. seurati displays new additional features such as kleistozooids ( kleistós = closed) and chaotic celleporoid layers. Kleistozooids are clearly distinguishable polymorphs characterized by the presence of a compact, imperforate frontal membrane and by a strongly reduced lumen of the "opesium". They commonly aggregate in clusters of regularly-arranged individuals that store a large quantity of proteic material. The inferred function of these cell-like structures is to supply nutrients for basic colony activities. Celleporoid layers are, possibly, a developmental relaxation of the colony of C. seurati for a more efficient use of space in competitive interactions.
Both celleporoid layers and kleistozooids reveal the magnitude of intracolony variability of a widespread opportunistic bryozoan species.  相似文献   

Resource Competition and Selective Grazing of Plankton in a Multispecies Pelagic Food Web Model*     

Roel Riegman  Bouwe R. Kuipers 《Marine Ecology》1994,15(2):153-164

Abstract. An idealized mathematical, multispecies model of the pelagic foodweb was used to explore the impact of resource competition, selective grazing, and species composition within each trophic level on the structure and functioning of a foodweb at a variety of light irradiance and nutrient levels. This concept is based on the general assumption that poorly edible species are poor competitors. The concept demonstrates that with increasing eutrophication, specialists in competition will be replaced by generalists and subsequently by poorly edible primary producers. Controlling factors not only determine the growth rate of primary producers but also select predators according to their ability to utilize the energy fixation of the system. Plankton community structure seems to adapt in such a way that the energy fixation rate of the system is optimized at a given set of nutrients and light. Red tides, dense algal blooms in shallow lakes and the varying results of biomanipulation in shallow lakes, can be explained by the concept of selective grazing. If this assumption is correct, the same ecosystem concept may be applicable for terrestrial ecosystems.  相似文献   

Prey consumption of Australasian gannets (Morus serrator) breeding in Port Phillip Bay, southeast Australia, and potential overlap with commercial fisheries     

Bunce  Ashley 《ICES Journal of Marine Science》2001,58(4):904-915

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Cultured Atlantic salmon in nature: a review of their ecology and interaction with wild fish   总被引：4，自引：0，他引：4  

Jonsson  Bror; Jonsson  Nina 《ICES Journal of Marine Science》2006,63(7):1162-1181

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Complementary (secondary) metabolites in a soft coral: sex-specific variability, inter-clonal variability, and competition   总被引：2，自引：0，他引：2  

Beatriz Fleury  John Coll  & Paul Sammarco 《Marine Ecology》2006,27(3):204-218

Sex‐specific interactions involving competition for space between the dioecious alcyonacean soft coral Sarcophyton glaucum and the scleractinian coral Acropora robusta were assessed experimentally on Bald Rock, central region of the Great Barrier Reef. To examine this, plus inter‐clonal responses, one male colony of S. glaucum, known to produce sarcophytoxide as its predominant complementary (secondary) metabolite, was sectioned, producing 10 clones. The same was done for a female colony. These two sets of clones were then relocated to grids and placed in contact with Acropora clones. Relocated and non‐relocated controls were also monitored. High levels of tissue necrosis were observed in the hard coral under contact conditions with both the male and female clones after 20 days. The development of a protective polysaccharide layer in the alcyonacean was also observed. Differences observed in the concentrations of complementary metabolites within the two different S. glaucum colonies were related to sex. Both under competition and non‐competition conditions, females exhibited significantly higher concentrations of sarcophytoxide than males, and this increased with time. Fatty ester concentration was also higher in females than males, varying significantly through time, and falling dramatically just after spawning. Fatty ester concentrations decreased linearly through time in the male clones. When involved in competition for space, females possessed higher concentrations of fatty esters than males, both at the site of contact and in non‐contact sites, again, decreasing after spawning. No significant changes in sarcophytoxide levels were noted in the parental colonies, but such changes were observed in fatty esters, with the female producing higher concentrations until after spawning. The use of these two variates in the form of a ratio (sarcophytoxide concentration:fatty ester concentration) yielded a variable Rho (ρ) which was a more sensitive indicator of biochemical change than either of its components alone. These two sets of compounds appeared to have a negative association through time and varied highly significantly between sexes. The diterpene sarcophytoxide may be considered an allelopathic or stress metabolite, while the lipids act as energy storage metabolites.  相似文献   

不同起始浓度对塔玛亚历山大藻和赤潮异弯藻种群竞争的影响   总被引：16，自引：0，他引：16  

董云伟  董双林  刘相义 《中国海洋大学学报(自然科学版)》2004,34(6):964-968

初步分析了起始浓度对塔玛亚历山大藻 (AlexandriumtamarenseBalech)和赤潮异弯藻 (HeterosigmaakashiwoHa da)种群增长的影响。在单种培养的情况下 ,A .tamarense与H .akashiwo的生长曲线可用逻辑斯谛增长模型拟合。不同起始浓度 ( 0 .2× 10 4,0 .5× 10 4,0 .8× 10 4cell/mL)对A .tamarense环境容纳量 (K)有明显的影响 ,随起始浓度的增加K有减小的趋势。H .akashiwo种群瞬时增长率 (r)随起始浓度增加而增加。按不同接种比例进行混合培养 ,不同起始浓度对 2种藻竞争的结果具有明显影响。当接种比例为A .tamarense∶H .akashiwo(A∶H) =1∶4时 ,H .akashiwo在竞争中占优势 ,而当A∶H =1∶1及A∶H =4∶1时 ,A .tamarense在竞争中占优势。竞争结果不仅受营养盐限制 ,克生物质对竞争结果亦具有重要影响。  相似文献