Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation proc...Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation process and these mammals are subject to lethal control.However,whether the negative impact of small mammals is solely a result of population size or also a result of activity and behavior has not been tested.In this study,we use plateau pika as a model to compare population size,core area of colony,and the number of burrow entrances and latrines between lightly and severely degraded grassland.We test whether the alleged contribution of pika to grassland degradation is a result of increased population size or increased burrowing activities of individuals in response to lower food abundance.We found that grassland degradation resulted in lower plant species richness,plant height,and biomass.Furthermore,the overall population size of pika was not significantly affected by location in lightly and severely degraded grassland.However,pika core areas in severely grassland degradation were significantly larger and had significantly higher densities of burrows and latrines.Our study provides convincing evidence that habitat-induced changes in the behavior of small,burrowing mammals,such as pika,can exacerbate grassland degradation.This finding has significant implications for managing small mammals and restoring degraded grassland ecosystems.展开更多
以加州扁鸟蛤(Clinocardium californiense)为实验对象,研究了底质厚度和含沙量对其潜沙行为以及碱性磷酸酶(AKP)、琥珀酸脱氢酶(SDH)和乳酸脱氢酶(LDH)活性的影响。底质厚度设0、1.5、3.0、4.5和6.0 cm 5个梯度,含沙量设0、25%、50%、...以加州扁鸟蛤(Clinocardium californiense)为实验对象,研究了底质厚度和含沙量对其潜沙行为以及碱性磷酸酶(AKP)、琥珀酸脱氢酶(SDH)和乳酸脱氢酶(LDH)活性的影响。底质厚度设0、1.5、3.0、4.5和6.0 cm 5个梯度,含沙量设0、25%、50%、75%和100%5个梯度,每个梯度设3个重复。在海水盐度30、温度17℃条件下,观察记录每组加州扁鸟蛤的存活率和潜沙率,测定内脏组织团中呼吸代谢酶的活性。结果发现:随着含沙量和底质厚度的增加,加州扁鸟蛤的存活率升高,潜沙率也与之呈正相关。AKP活性随含沙量升高逐渐降低,在含沙量为75%时酶活性达到最高;随着底质厚度的增加,酶活性先升高后降低,在厚度为3 cm时酶活性最高。SDH活性随着含沙量升高而升高并趋于稳定,在含沙量75%、100%时酶活性最高;底质厚度的增加与SDH活性的关系也呈先升后降趋势。LDH活性的变化规律则与AKP和SDH相反,即含沙量的增加会促使酶活性平稳下降,且在75%时至最低值;底质厚度的增加则促使酶活性逐渐升高并趋于稳定,且在6 cm时达到稳定。本研究可为加州扁鸟蛤野生种质资源的保护和人工育苗提供参考资料。[中国渔业质量与标准,2019,9(2):24-31]展开更多
The present study describes the habitats, life cycle, larvae growth, burrowing behavior and terrestrial adaptation of Spadefoot toads in Israel based on observations and data collected during more than 30 years in nor...The present study describes the habitats, life cycle, larvae growth, burrowing behavior and terrestrial adaptation of Spadefoot toads in Israel based on observations and data collected during more than 30 years in northern Israel. The distribution area in Israel is from the north in the Upper Galilee and Golan Heights (annual rainfall range of 500 - 1000 mm) to the southern coastal plain (annual rainfall of about 250 mm). Among the 51 different breeding places of amphibians, only ponds where water was available for a few months were used by Spadefoot toads and metamorphosed populations were found around these ponds. The larvae underwent metamorphosis during the summer and autumn in northern Israel, and during the spring in central and southern Israel. A negative correlation exists between the percentage of toads burrowing and soil moisture levels, with greater burrowing behavior occurring under dry conditions. The plasma concentration increased during burrowing by electrolytes and urea accumulations. The burrowing behavior helped Spadefoot toads survive in this area at the southern border of its distribution.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32192461).
文摘Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation process and these mammals are subject to lethal control.However,whether the negative impact of small mammals is solely a result of population size or also a result of activity and behavior has not been tested.In this study,we use plateau pika as a model to compare population size,core area of colony,and the number of burrow entrances and latrines between lightly and severely degraded grassland.We test whether the alleged contribution of pika to grassland degradation is a result of increased population size or increased burrowing activities of individuals in response to lower food abundance.We found that grassland degradation resulted in lower plant species richness,plant height,and biomass.Furthermore,the overall population size of pika was not significantly affected by location in lightly and severely degraded grassland.However,pika core areas in severely grassland degradation were significantly larger and had significantly higher densities of burrows and latrines.Our study provides convincing evidence that habitat-induced changes in the behavior of small,burrowing mammals,such as pika,can exacerbate grassland degradation.This finding has significant implications for managing small mammals and restoring degraded grassland ecosystems.
文摘The present study describes the habitats, life cycle, larvae growth, burrowing behavior and terrestrial adaptation of Spadefoot toads in Israel based on observations and data collected during more than 30 years in northern Israel. The distribution area in Israel is from the north in the Upper Galilee and Golan Heights (annual rainfall range of 500 - 1000 mm) to the southern coastal plain (annual rainfall of about 250 mm). Among the 51 different breeding places of amphibians, only ponds where water was available for a few months were used by Spadefoot toads and metamorphosed populations were found around these ponds. The larvae underwent metamorphosis during the summer and autumn in northern Israel, and during the spring in central and southern Israel. A negative correlation exists between the percentage of toads burrowing and soil moisture levels, with greater burrowing behavior occurring under dry conditions. The plasma concentration increased during burrowing by electrolytes and urea accumulations. The burrowing behavior helped Spadefoot toads survive in this area at the southern border of its distribution.
