穿龙薯蓣种群濒危机制的连续时间马尔可夫过程分析

依据吉林省三岔子林业局、松江河林业局, 黑龙江省帽儿山林场、凉水保护区实验地资料, 建立了穿龙薯蓣种群濒危机制的CTM(Continuous Time Markov Approach)模型。运用该模型进行了穿龙薯蓣种群随海拔高度的演化趋势预测和自然、人为因素影响程度的对比分析。研究结果表明:2700~2 900 m 区间穿龙薯蓣种群密度相对稳定, 长势相对良好, 其它地段较差。受自然和人为因素的影响, 穿龙薯蓣种群总体濒危, 但影响因子周期长短不一, 有些因子可以人为控制、有些则是自然发生的。根据研究结果提出了相应的濒危保护措施。     

东灵山辽东栎群落演替的连续时间马尔可夫过程研究

采用连续时间马尔可夫方法研究了北京东灵山辽东栎群落的演替过程,在综合考虑影响因子、物种构成和年龄分布等因素的基础上,建立了辽东栎群落演替的马尔可夫模型,模拟出了辽东栎群落演替的主要趋势。     

Critical thermal tolerance polygons of tropical marine fishes from Sulawesi,Indonesia

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Replicate thermal tolerance polygons were created using critical thermal methodology (CTM) and statistically compared.     

Physiological tolerance to hyperthermia and hypoxia and effects on species richness and distribution of rockpool fishes of Loggerhead Key, Dry Tortugas National Park

Rockpools on Loggerhead Key in the Dry Tortugas National Park experience cyclic tidal changes in water quality and physical dimension resulting in ichthyofaunal assemblages that differ markedly from the adjacent coral reef. Within the beach rock formations and areas transitioning to the nearby reef, we observed 45 fish species; however, only four species - schoolmaster, Lutjanus apodus, French grunt, Haemulon flavolineatum, cocoa damsel, Pomacentrus variabilis, and frillfin goby, Bathygobius soporator - were found in all rockpools. All fishes were transient juveniles except for frillfin goby, which was a pool resident. High temperature tolerance, (Critical Thermal Maxima), and low oxygen tolerance, (Critical Oxygen Minima) for schoolmaster, French grunt, cocoa damsel, and frillfin goby were 40.9, 36.2, 37.6, 40.9 °C and 0.56, 0.77, 0.50, and 0.27 mg/L, respectively. All four species demonstrated thermal and hypoxia tolerance values similar to those published for species traditionally noted as abiotic specialists. Although fish distribution patterns in rockpools were likely influenced by structural complexity and spatial limitations, the relationship between pool morphology and species richness was weak, suggesting that physiological tolerance to high temperature and low oxygen among reef fishes may be more influential in determining which species inhabit the rockpools. Harsh thermal and oxic conditions that cannot be exploited by less tolerant species may be beneficial for some Loggerhead Key reef fishes in providing refuge from predators, foraging grounds, or potential nursery areas.