第 II 部分：种群生态学 ( Population Ecology)

第 5 章 Population Distribution and abundance 种群分布与数量

Population 种群： A group of individuals of a single species inhabiting a specific area. 居住在特定区域的某种生物所有个体 )

Environment limits the geographic distribution of species

On small scales, individuals within populations are distributed in patterns that may be random, regular, or clumped

On large scales, individuals within populations are clumped

Population density declines with increasing organism size

9.1 Distribution Limits

（ 1 ） Kangaroo Distributions and Climate

红袋鼠

灰袋鼠大袋鼠

澳洲三种袋鼠的分布与气候的关系

Environment limits the geographic distribution of species

During the last glacial period, C. longilabris lived far south of its present range limits. Then with climate warming and the retreat of the glaciers, the beetles followed their preferred climate northward and up in elevation into the mountains of western NM.

C. longilabris confined to cool environments

(2) A Tiger Beetle of Cold Climates

（续）Physiological ecology:

Water loss rates ( 水分散失率 ), metabolic rates ( 代谢速率 )

Body temperature preference

( 体温偏好 ) , et al. The studies show that

environmental limits may be

stable for long periods of

time and across an extensive

geographic range Uniform temperature preference across an extensive geographic range

分开一万年

（ 3 ） Distributions of plants along a moisture-temperature gradient （梯度）

The distribution of four Encelia species in southwestern North America

无毛被 , 反射约 15％

略被毛 ,反射约 26

％

The humidity declines, but temperature increases

夏季叶密被毛 , 反射约 40 ％ 叶面光滑

（续）

Light absorption by leaves of Encelia

Though they have

different densities

of pubescent

leaves, they have

similar leaf

temperatures.

How can that be?

E. farinose and E. frutescens are overlapped in distribution.

（续）Losing heat by transpiration( 蒸腾降温 ) needs more water

Temperature regulation and distributions of E. farinosa and E. frutescens

Smooth leaves

(4) Distributions of Barnacles ( 藤壶 ) along an intertidal( 潮间） exposure gradient

Why does Chtham

alus stay at higher

levels if it survives

well at the lower?

Distributions of two barnacle ( 藤壶） species within the inter-tidal zone

?

（续）

Chthamalus survives very well in the lower zone. But why not?

Vulnerability to Desiccation( 干燥） ? Yes. But it is enough?

上潮间带藤壶的死亡率

larvae adults

9.2 Patterns on Small Scales

On small scales, individuals within populations are distributed in patterns that may be random, regular, or clumped

Small scale ： areas over which there is little environmental change significant to the organism under study.

Large scale: areas over which there is substantial environmental change.

Scale !

(1) Three distribution patterns on small scales

随机 均匀 聚集

（ a ） Distribution of tropical bee colonies ( 蜜蜂群）

Bees: Stingless bees (Trigonalydae) in tropical dry forest

in Cost Rica

Habits: Feeding pollen and nectar; nesting on trees; some

species are highly aggressive and foraging in groups, while

others are not.

question ： Is there a relationship between aggressiveness and

colony distribution pattern ?

Research methods: (i) Mapping distributions of trees

suitable for nesting, and then (ii) mapping nests.

Results:

(b) Distribution of desert shrubs 荒漠灌木的空间分布

Are local population of the creosote ( 木馏油 )distributed regularly?

Regular, Random, Clumped, or Both?

（续）Phillips & MacMahon (1981):

续Methods: Competition belowground? Excavating( 挖 ) ro

ots, and then mapping them. Conclusion: The competition influences the distribution.

Creosote bush root distributions: hypothetical versus actual root overlap (1994)

Most of species are

distributed in

small areas, while

only a few in large

areas.

(1) Geographic range sizes

9.3 Distribution on large scales

(2) Range size and abundance

A positive relationship

J. Damuth （ 19

81 ） : 307 herbiv

orous mammals f

rom as small as 1

0g in a small mice

to as large as 106

g rhino,

Body size and population density of herbivorous ( 植食性） mammals （哺乳动物）

Negative correlation

9.4 Organism size and population density

(1) Animal size and density

Animal size and population density

（ i ） overall pattern: negative correlation between S and D

（ ii ） Aquatic invertebrates tend to have higher densities than terrestrial invertebrates.

(iii) Mammals tend to have higher densities than birds

White （ 1985 ） found

a similar relationship b

etween plant size and d

ensity in plants as that i

n animals.

Plant size and population density

浮萍 红树

（ 2 ） Plant size and Density

The value of such relationships?

9.5 Factors that Limit Distributions限制分布的因素

Temperature, Moisture, and Other Physical Factors

Dispersal Habitat Selection

Interrelations with other species

Distribution

9.6 Methods for Analyzing Distributions

（ 1 ） Transplant ( 移植 ) Experiments

Liebig’s Law of the Minimum ( 李比希最小因子定律）： the

rate of any biological process is limited by the factor in least a

mount relative to requirements. 低于某生物需要的最小量的任何特定因子，是决定该种生物生存和分布的关键因素。

移植存活

实际分布区

潜在分布区

（ 2 ） Physiological Ecology

Shelford’s Law of Tolerance (Shelford 耐受性定律）： The distr

ibution of a species will be controlled by that environmental fact

or for which the organism has the narrowest range of tolerance.

物种的分布范围受忍耐性最窄的环境因子限制

（ 3 ） Adaptation 适应性

(i) A process of genetic change in a population

whereby, as a result of natural selection, the average

state of a character becomes improved with

reference to a specific function, or

whereby a population is thought to have become

better suited to some feature of its environment.

(ii) Also, an adaptation: a feature that has become

prevalent in a population because of a selective

advantage conveyed by that feature in the improvement

in some function.

剪谷颖

（ 4 ） Habitat Selection 生境选择

寻觅寄主 找到寄主

评价寄主

产卵

卵和幼虫发育爬出幼虫结茧

羽化

交配

迁徙鸟的生境选择

Applications: Rarity and Extinction( 稀有和绝灭 )

Geographic range:

Habitat tolerance:

Local population size:

extensive restricted

broad narrow

Large small

7 combinations – rarity; 1 combination - common

Three factors ?

Most common Rarest

思考题

1. 假设你在沙漠中发现了一种新蜥蜴，如何描述它的生境？如何研究其生境范围？

2. 环境结构（如土壤类型和土壤湿度的分布）对植物的分布格局有何影响？植物间的相互作用是如何影响其分布格局的？

3. 有 2 种植物，一种是以种籽繁殖的，种籽随风传播；另一种无性繁殖，靠枝蔓发芽繁殖。这两种繁殖方式对其分布格局有何影响？

课堂作业选择 2 个坐标图，概括出其所表达的结果或结论。