生態(tài)保護(hù)和維持生物多樣性越來(lái)越受到公眾的關(guān)注。水生態(tài)系統(tǒng)是生態(tài)保護(hù)和維持生態(tài)多樣性的重要領(lǐng)域。由于經(jīng)濟(jì)社會(huì)發(fā)展,污染物排放增加,造成水生態(tài)系統(tǒng)失衡,危及水生態(tài)系統(tǒng)平衡和生物多樣性。生態(tài)保護(hù)和維持生物多樣性是全球生態(tài)保護(hù)研究面臨的緊迫問(wèn)題。定量研究某一生態(tài)系統(tǒng)中特定物種的種內(nèi)競(jìng)爭(zhēng)表型改變和環(huán)境變化條件下物種生存繁衍是維持生態(tài)系統(tǒng)中的生物多樣性的重要領(lǐng)域;相關(guān)的科學(xué)研究對(duì)水生態(tài)系統(tǒng)的修復(fù)與保護(hù)維持生物多樣性具有重要的意義。本文研究對(duì)象是一種以鰓呼吸的淡水螺,隸屬于平吻螺科,廣泛分布于美國(guó)東南部。淡水螺作為水生態(tài)系統(tǒng)中初級(jí)消費(fèi)者之一,對(duì)于生態(tài)食物網(wǎng)的能量傳遞以及水生態(tài)系統(tǒng)穩(wěn)定有著至關(guān)重要的作用。特別是在水體富營(yíng)養(yǎng)化中,有害藻類(lèi)爆發(fā)會(huì)導(dǎo)致底棲生物的食物以及棲息地改變,改變其生活史以及表型變化,從而影響其生存;改變淡水螺食物網(wǎng)結(jié)構(gòu),對(duì)于其生物種群以及整個(gè)水生態(tài)系統(tǒng)穩(wěn)定性都將造成影響。淡水螺食物供給水平是淡水螺種內(nèi)競(jìng)爭(zhēng)表型改變、體型變化的重要因素,特別是在高密度種群中。食物的變化不僅會(huì)使淡水螺種內(nèi)競(jìng)爭(zhēng)表型和體型改變,也會(huì)改變某些營(yíng)養(yǎng)元素在淡水螺不同器官中的吸收和流動(dòng),從而影響淡水螺物種的生存和繁衍...

【文章頁(yè)數(shù)】：64 頁(yè)

【學(xué)位級(jí)別】：碩士

【文章目錄】：
摘要
abstract
Chapter1.Introduction
    1.1 Interspecific competition and intraspecific competition of aquatic system
        1.1.1 natural competition introduction
        1.1.2 intraspecific competition dominant
    1.2 Freshwater snail competition
        1.2.1 consequence of freshwater snails’competition
        1.2.2 interspecific competition and intraspecific competition research cases of freshwater snails
        1.2.3 freshwater snails’competition mechanism from nutrient assimilation analysis
        1.2.4 Knowledge gap between previous studies and my research
    1.3 Isotope analysis and gastrointestinal tract content for species
        1.3.1 isotope analysis development and apply
        1.3.2 process and difficulties of isotope analysis in biotic samples
        1.3.3 gastrointestinal tract content apply
    1.4 Research significance and objectives
        1.4.1 significance for aquatic ecosystem
        1.4.2 objective of the field study
        1.4.3 objective of the lab control feeding
        1.4.4 objective of the isotope analysis
Chapter2.Methods
    2.1 Study area
    2.2 Study species
    2.3 Field study of freshwater snails with gradient density change
    2.4 Lab cultured experiment
    2.5 Stable isotope carbon and nitrogen process
        2.5.1 overall idea of stable isotope analysis
        2.5.2 pretreatment and key steps of stable isotope analysis
        2.5.3 models and calculation for stable isotope analysis
Chapter3.Result
    3.1 Field experiment
        3.1.1 abiotic parameters of the creek
        3.1.2 phenotype alterations and AFDM response to gradient freshwater snails’density change
        3.1.3 final individuals in14 experiment units(immigration)
        3.1.4 guts content in field freshwater snails’samples
    3.2 Lab culture phenotype result
        3.2.1 phenotype change in50 sampling days consequence
        3.2.2 correlations of length and weight in three groups
    3.3 Isotope analysis for carbon and nitrogen of freshwater snails’samples
        3.3.1 stable isotope nitrogen and carbon in freshwater snails’gonads and muscle
        3.3.2 transmitting rate(assimilation rate)of the body parts with different treatment..
Chapter4.Discussion
    4.1 Field result discussion
        4.1.1 phenotype change with increasing density
        4.1.2 AFDM(food quantity)response to increasing density
        4.1.3 conclusion to prove the hypothesis
        4.1.4 optimal freshwater snails’population density
        4.1.5 shortcoming for the field study
    4.2 Lab food control feed study
        4.2.1 our chosen food type and actual freshwater snails’guts food content
        4.2.2 nitrogen and carbon assimilation difference
        4.2.3 freshwater snails’life strategy response to food type change
        4.2.4 phenotype change to carbon and nitrogen turnover rate of the muscle parts
    4.3 Reliability of lab experiment analysis in our study
        4.3.1 isotope analysis errors
        4.3.2 gastrointestinal tract content errors
    4.4 Future study research
        4.4.1 perfection about my study
        4.4.2 my study involved with water pollution studies
Chapter5.Conclusion
Reference
Acknowledgement



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