Knowledge Resource Center for Ecological Environment in Arid Area
| 两种麻蜥对温湿度和食物改变的生活史响应 | |
| 其他题名 | Life history response to changes in thermal, hydric and food conditions in two Eremias lizards |
| 汪洋 | |
| 出版年 | 2017 |
| 学位类型 | 博士 |
| 导师 | 杜卫国 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 由人类活动引起的全球变暖对生物多样性的威胁涵盖了从基因到整个生态系统的各个层面。目前许多尝试预测未来生态系统对气候变暖响应的研究都聚焦在与温度相关的气候因子改变上。除了温度上升外，全球变暖对环境因子的改变还包括热浪和降水的频次、强度和持续时间的改变。更重要的是，全球变暖还可能通过对紧密关联物种生物学和生态学特征的差异化影响食物网关系。在荒漠地区，土壤湿度降低限制了蒸发冷却效应，导致夏季温度剧烈升高，使该区域面临最为严峻的高温和干旱前景，可能严重威胁该区域生物的生存与繁衍，乃至生态系统的平衡。蜥蜴是荒漠地区的主要脊椎动物类群，也是区域食物链的重要组成部分。作为外温动物，蜥蜴的多数生理功能和生活史特征都依赖于外界环境条件，因而对环境变化异常敏感。因此，本研究通过实验操纵温度，湿度和食物因子，探讨荒漠地区两种蜥蜴[密点麻蜥(Eremias multiocellata)和丽斑麻蜥(Eremias argus)]的母体繁殖、胚胎发育和后代表型对环境改变的响应。得到以下结果：高温显著影响密点麻蜥的怀仔期，繁殖输出和幼体性别比例，但对幼体表型没有影响。此外，高温对母体繁殖的作用受降水量的影响。干旱不仅会降低母体繁殖输出和产后身体状态，还加剧高温对幼体存活率以及后代性比的影响。在半干旱种群中，干旱降低母体的水摄入量，进而显著降低丽斑麻蜥母体的免疫功能，使其更易受寄生虫感染； 而干旱种群母体水摄入量降低后免疫力下降则较小。同时，在干旱条件下，母体增加窝卵数、降低卵重，并提高卵的水汽传导率变化范围。这可能有助于胚胎通过改变卵的通透性以更好地利用环境中的水分并避免失水，但并不会明显减轻低湿度孵化条件对半干旱种群孵化率和幼体存活率带来的负面影响。低湿度下孵化将对丽斑麻蜥(Eremias argus)的胚胎孵化率，幼体形态和存活率造成显著负面影响。干旱条件孵化会显著降低半干旱种群幼体的孵化率存活率等适合度相关指标，而对干旱种群所影响较小。这提示我们，半干旱种群由于相比干旱种群对干旱更高的敏感性，气候变暖带来的区域性干旱前景响应将对它们造成更为严重的影响。食物缺乏显著恶化密点麻蜥繁殖母体的身体状态和免疫功能。食物限制会促使密点麻蜥减少窝仔数，并使后代在同样食物处理下体重增加更快，存活率提高。然而，代间传递的幼体补偿生长效应与功能表现表现出明显的权衡，这些幼体体重增加更快，但运动能力却显著下降，这有可能会提高幼体在捕食和天敌回避过程中的风险。 随着气候变暖，未来荒漠地区生态系统将面临高强度和持续时间更长的热浪，降水和土壤湿度的减少以及食物匮乏。我们的结果显示，上述环境因子变化将影响本区域蜥蜴物种的繁殖过程，使之面临严峻挑战。作为该区域的主要脊椎动物类群和食物链的重要组成部分，荒漠蜥蜴种群的减少甚至灭绝将会极大地降低该区域的生物多样性和生态系统稳定性。在未来的研究中我们应开展多环境因子改变对生态系统结构，组成和功能影响的研究将有助于我们更准确地预测和解释未来生态系统对环境变化的响应模式。 |
| 英文摘要 | Anthropogenic global warming (AGW) represents a major threat to biodiversity at all levels of organization. Much current ecological research attempts to predict the future responses of ecosystems to focusing on temperature-related effects of AGW. However, besides temperature rising per se, attendant changes with global warming are also included effects such as changes in the frequency, intensity and duration of heat waves and precipitation events. Most importantly, AGW may unravel food webs by differentially affecting the biology and ecology of species involved in intimate interactions, where reciprocal selection forces are often strong. Changes in regional temperature and water cycle in response to the warming over the 21st century will not be uniform. In many mid-latitude and subtropical arid regions, mean precipitation will likely decrease. Deficits in soil moisture can lead to more frequent and severe hot summer temperatures in arid regions, where evaporative cooling is limited by available moisture. Which will put the ecosystem of arid region in danger of substantially temperature rising and drought spell. Additionally, reduced precipitation suppressed NPP (net primary productivity) and NEE (net ecosystem exchange）, which will negatively affect biodiversity and population demography of all trophic level trough food chain in of arid region. In this study, we experimentally manipulated the environmental factors, including temperature, humidity and food availability to mimic the changes which had been predicted to be locally occurring in future and investigated the effects on female reproduction and offspring traits in arid region lizards. Which provide a model system to study the effects of changes in environmental factors above on reproductive traits of izards for the following reasons. First, ectothermic animals like lizards are sensitive to climatic changes because most of their physiological function are determined by ambient environment. Second, reproduction which directly affect the fitness of individual and hence the population dynamics is essential part of life history because it is the most vulnerable stage of life account for the narrowest threshold to environmental factors and immediate impact on population demography. Third, the lizards are the main fauna of the arid region and the main component of the local food web, the decrease or even disappearance of lizard populations due to climate warming would lower the regional biodiversity. And several meaningful results have been discovered by our study as follow:High temperatures significantly affected the gestation period and reproductive output of females and the offspring sex ratio in multi-ocellated racerunners（Eremias multiocellata）which was proven a（Temperature-dependent sexual determination， TSD）species, but had little impact on offspring body size and mass. More interestingly, the effect of high temperatures on female reproductive output was not consistent between two consecutive years that differed in precipitation. Low precipitation may not only worsen the body condition of postpartum females but also aggravate the impact of climate warming on lizards and negatively affect the survival of lizards and sex ratio of offspring for those TSD species in the desert steppe.Low incubational humidity had negative influences on hatching success of eggs, phenotypic traits and survival rate of offspring in Mongolian racerunner (Eremias argus）. All impacts of low humidity on lizards were more substantial for arid steppe population, while lizards from arid desert population were not significantly affected by the range of humidity treatment in our study. Which indicated that climate warming could be responded differently among populations by wide distributed species on account of their diverged resistance to the same extent of change in environmental factors.Water restriction significantly worsens the immune function of females in E. argus during reproduction. As a result, females in low water availability treatment suffered from parasites more severely and had higher long-term mortality than those in high water availability treatment. Females in water restriction treatment laid more but smaller eggs, which had wider range of water vapor conductance. However, those strategies won’t mitigate the negative effect of low incubational humidity on hatching rate and survival rate of offspring. Again, we found that females and offspring of arid desert population were less affected by water restriction or low incubational humidity. Food scarce significantly worsen the body condition and immune function of postpartum females in E. multiocellata. Females in food restriction treatment had less but bigger offspring. Food restriction will induce apparent maternal effect on the neonates which drove them to grow heavier and hence increased survival rate in the same food supplement. However, this trans-generation compensatory growth had obvious side effect that will lower the locomotion performance in those offspring. Which could increase the risk of mortality in prey foraging and predation escaping.Our results provide evidence that the attendant changes with climate warming in mid-latitude arid region, such as increased duration and intensity of heat waves, decreased precipitation and soil moisture and consequently suppressed NPP, NEE and potential food availability, will determine the life history of lizards, and suggest that the future climate changes in arid regions, will likely impose severe pressure on lizards. Since which was the main fauna of the arid region and the main component of the local food web, the decrease or even disappearance of lizard populations would lower the biodiversity and stability of regional ecosystem. Therefore, ectothermic animals like lizards which habituated in vulnerable ecotone to climate warming like arid regions should receive more attention in future studies. In addition, effects of multiple environmental changes on ecosystem structure, composition and function should be taken into consideration for investigations which attempt to achieve accurate anticipatory and explanatory predictions to the future responses of ecosystems. |
| 中文关键词 | 气候变暖 ; 热浪 ; 干旱 ; 食物缺乏 ; 爬行动物 ; 生活史响应 |
| 英文关键词 | Global warming Heat wave Drought Food shortage Reptile Life history response |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院动物研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287884 |
| 推荐引用方式 GB/T 7714 | 汪洋. 两种麻蜥对温湿度和食物改变的生活史响应[D]. 中国科学院大学,2017. |
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