張楊家豪 Chia-Hao Chang-Yang
國立中山大學生物科學系
Department of Biological Sciences, NSYSU
changyang@mail.nsysu.edu.tw
高中生物科學資優培育計畫
物種多樣性的維持機制
台灣的植物區系界
台灣為全北域(Holarctic region)與古熱帶域 (Paleotropic)的交會處
(Takhtajan, 1986, Floristic Regions of the World)
http://www.geocities.com/jacobzhu/taigeol.htm
沉積岩
氣候分區
溫量指數
Warmth Index (溫量指數,Kira 1945) = Sum of (TM-5) when TM is above 5℃ TM: Monthly Mean Temperature
台灣生態特色
位置
介於熱帶與亞熱帶
兩大植物區系交會處
鄰近歐亞大陸的島嶼
平面
夏、冬雨差異 (西南季風 + 東北季風)
地質多樣化
將近60%的面積為森林
立體
錯綜複雜的地形
海拔變異大
人為與自然干擾強
很高的生態系多樣性、物種多樣性
台灣的植物概況
蕨類植物
37科 (全世界65科) 145屬 630種
裸子植物
8科 (全世界11科) 17屬 28種
被子植物
190科 (全世界291科) 1257屬 3681種
合計共235科 1419屬 4339種
(4077原生種 + 262歸化種)
海拔與及特有率之關係
台灣的特有種計有1069種,特有率為26.2%。特有種的比率隨著海
拔的升高由低海拔地區的17.6% 逐步上升至亞高山帶的59.2%。在
緯度上,特有率則由北部往南部遞增。
台灣多樣的植被帶
Lin, H.-Y., Li, C.-F., Chen, T.-Y., Hsieh, C.-F., Wang, G., Wang, T. & Hu, J.-M. (In press) Climate-based approach for modeling the distribution of montane forest vegetation in Taiwan. Applied Vegetation Science. doi: 10.1111/avsc.12485
Altitudinal diversity gradient in
Taiwan
Pasoh Forest Reserve
2°58’47”N, 102°18’29”E
Latitudinal gradient in biodiversity
Francis, Anthony P. & Currie, David J. (2003) A globally consistent
richness‐climate relationship for angiosperms. The American Naturalist, 161, 523-536. doi: 10.1086/368223
Latitudinal gradient in biodiversity
Species–area curve
Reptile and amphibian in Antilles
(MacArthur and Wilson 1967)
Plant species in Great Britain (Rosenzweig 1995)
Habitat diversity increases with area
Isopod data from the Aegean Islands (Hortal et al. 2009)
Theory of island biogeography
MacArthur and Wilson (1967)
Species–Abundance Distribution
(SAD)
R. A. Fisher (1890-1962) F. W. Preston (1896-1989)Preston, F. W. (1948) The commonness, and rarity, of species.
Niche apportionment models
(Broken-stick model)
Species–Abundance Distribution
(SAD)
Neutral Theory
Steve Hubbell
Latitudinal gradient in biodiversity
Francis, Anthony P. & Currie, David J. (2003) A globally consistent
richness‐climate relationship for angiosperms. The American Naturalist, 161, 523-536. doi: 10.1086/368223
Ecological hypothesis:
Climate and species richness
Ecological hypothesis:
Historical hypothesis:
The time-integrated area hypothesis
Evolutionary hypothesis:
Rates of diversification
Evolutionary hypothesis?
Angiosperm speciation cools down in the
tropics
The paradox of the plankton
Modern Coexistence Theory
Peter Chesson (2000)
• Unstable coexistence
– Species coexist for a long
time due to slow rates of
competitive exclusion
– Species will eventually
disappear
• Equalizing mechanisms
– Reduce fitness difference
– Hubbell’s neutral theory
• Stable coexistence
– Species recover from low
density
– No long-term trends in
species density
• Stabilizing mechanisms
– Fluctuation independent
• Niche partitioning • Density dependence– Fluctuation dependent
• Storage effect • Intermediate Disturbance HypothesisCanopy gaps: Patch dynamics
• A forest can be thought of as a set of patches of
widely varying sizes that have experienced
Neutral theory: assumptions
(Hubbell & Foster 1986)
• Zero-sum game: constant
total abundance
• All individuals & species
have an equal probability
of colonizing new sites
• Constant and fixed
Neutral theory
• Competition in a local community
– A random walk to single-species dominance
Ecological drift
• Population sizes of species fluctuate due to
stochastic events, and this fluctuation may
cause the disappearance of certain species
from a community
Neutral theory
• Competition in a local community
– A random walk to single-species dominance
• Ecological drift
– High abundance + low mortality rates
• Dominant species take very long time to out-compete other
species
• Local communities connect with a much larger
metacommunity
– Species immigration from the metacommunity
– New species in the metacommunity arise via
Testing the predictions of
the neutral theory
Testing the predictions of
the neutral theory
The value of the neutral theory
• Enormously influential
• Mathematically elegant and tractable
• Real communities represent a continuum of
niche and neutral interactions
• Emphasis how dispersal and regional species
pool may determine local community structure
Storage effect
Chesson & Warner (1981)
Storage effect
• Environmental variation includes
– Resource availability, rainfall, temperature, predation levels
• Species-specific environmental responses
– Asynchronization among species
• A relatively long-lived life stage
– Annual plants with long-lived seeds
– Zooplankton with diapausing (resting) eggs
• Covariance between environment and competition
Adler, P. B., J. HilleRisLambers, P. C. Kyriakidis, Q. Guan, and J. M. Levine. 2006. Climate variability has a stabilizing effect on the coexistence of prairie grasses. Proceedings of the National Academy of Sciences 103:12793.
Adler, P. B., J. HilleRisLambers, P. C. Kyriakidis, Q. Guan, and J. M. Levine. 2006. Climate variability has a stabilizing effect on the coexistence of prairie grasses. Proceedings of the National Academy of Sciences 103:12793.
Latitudinal gradient of forest diversity
explained by storage effects
Usinowicz, J., C.-H. Chang-Yang, Y.-Y. Chen, J. S. Clark, C. Fletcher, N. C. Garwood, Z. Hao, J. Johnstone, Y. Lin, M. R. Metz, T. Masaki, T. Nakashizuka, I.-F. Sun, R. Valencia, Y. Wang, J. K.
Zimmerman, A. R. Ives, and S. J. Wright. 2017. Temporal coexistence mechanisms contribute to the latitudinal gradient in forest diversity. Nature 550:105–108.
Latitudinal gradient of forest diversity
explained by storage effects
Intermediate Disturbance Hypothesis
Bongers, F., L. Poorter, W. D. Hawthorne, and D. Sheil. 2009. The intermediate disturbance hypothesis applies to tropical forests, but disturbance contributes little to tree diversity. Ecology Letters 12:798-805.