مباحث کلاسی ارزیابی و اندازه گیری مراتع (2)

 

مباحث کلاسی اکولوژی (4)

Food Web Terminology

Trophic level: level at which an animal feeds

Producer: autotroph = make food from nutrients in environment

Primary consumer: heterotroph = herbivore = eats producers

Secondary consumer: heterotroph = carnivore = eats animals that eat plants

Tertiary consumer: heterotroph = carnivore = eats other carnivores

Decomposers: microbes and fungi = “eat” dead organisms

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 Ecological pyramids

The standing crop, productivity, number of organisms, etc. of an ecosystem can be conveniently depicted using “pyramids”, where the size of each compartment represents the amount of the item in each trophic level of a food chain.

Note that the complexities of the interactions in a food web are not shown in a pyramid; but, pyramids are often useful conceptual devices--they give one a sense of the overall form of the trophic structure of an ecosystem.

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 Pyramid of energy

A pyramid of energy depicts the energy flow, or productivity, of each trophic level. 

Due to the Laws of Thermodynamics, each higher level must be smaller than lower levels, due to loss of some energy as heat (via respiration) within each level.

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 Pyramid of numbers

A pyramid of numbers indicates the number of individuals in each trophic level.

Since the size of individuals may vary widely and may not indicate the productivity of that individual, pyramids of numbers say little or nothing about the amount of energy moving through the ecosystem.

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 Pyramid of standing crop

A pyramid of standing crop indicates how much biomass is present in each trophic level at any one time. 

As for pyramids of numbers, a pyramid of standing crop may not well reflect the flow of energy through the system, due to different sizes and growth rates of organisms.

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 Inverted pyramids

A pyramid of standing crop (or of numbers) may be inverted, i.e., a higher trophic level may have a larger standing crop than a lower trophic level. 

This can occur if the lower trophic level has a high rate of turnover of small individuals (and high rate of productivity), such that the First and Second Laws of Thermodynamics are not violated.

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 Pyramid of yearly biomass production

If the biomass produced by a trophic level is summed over a year (or the appropriate complete cycle period), then the pyramid of  total biomass produced must resemble the pyramid of energy flow, since biomass can be equated to energy.

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چهارمین همایش ملی مرتع و مرتعداری (5 تا 7 آبان 1388)

 

مباحث کلاسی اکولوژی (3)

Clumped

Clumped dispersion has population occurring in patches.

Increased concentration of resources leads to clumping.

Defense against predators.

e.g. schools of fish.

Uniform

Even spacing of individuals within the population.

Diminishes competition.

Often seen with plants, they secrete chemicals that prevent germination and growth of individuals that may compete for resources.

Random

Spacing is varied and unpredictable.

Occurs in the absence of strong attraction (concentrated resources) or strong repulsion (avoidance of competition) between individuals.

This form of dispersal is rare.

 

A. Population - consists of all of the individuals of a species that live together in one place at one time.  

B. Focus of population ecology: Factors that  influence: Population size- Growth rate- Density- Structure.

C. In POPULATION: Not concerned with individuals- Populations , same area, same time- Population ecology,  looks at the dynamics of populations that are similar between species.

D. Population density:  number of individuals of a given species in a specific area at a given time.

E. Range:  geographic area or limit of a population.

F. When does population growth? When more individuals are born than die.

r  (intrinsic rate of increase) = birth rate - death rate

Evolutionary events occur because of the relationships between an organismic unit and their environment.

 Evolution more specifically refers to a change in gene frequencies or descent with modification.

مباحث کلاسی اکولوژی (2)

1.  Distribution of Organisms: Physiological, Population, Community, Evolutionary, Behavioral.

2.  Abundance of Organisms: Population, Community, Evolutionary, Behavioral.

3.  Distribution and Abundance at the Community Level: Community, Ecosystem, Landscape.

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Biosphere: part of Earth that supports life, including the top portion of Earth's crust, the atmosphere, and all the water on Earth's surface.

Biotic: living.

A biotic: non-living.

Organism: one of  any living thing.

Population: all the organisms that belong to the same species living in a community.

Community: all the populations of different species that live in an ecosystem.

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What is Biogegraphy?

Study of patterns of distribution of plants and animals in time and space together with the factors causing those patterns.

Zoogeography: Biogeography of animals.

Transitions in Biogeography

•       Descriptive (distribution) =>

•       Historical (fossil patterns, molecular) =>

•       Ecological (environmental analysis) =>

•       Predictive (development of theories)

Historical Biogeography: spatial and temporal distribution of animals based on historical events-interested in origins and relationships among biotas.

Ecological Biogeography: study of dispersal of animals, looks at mechanisms which maintain or change dispersal patterns-dynamics of biotas as ecological units.

Biogeography is the science that attempts to document and understand spatial and temporal patterns of biodiversity. It is a synthetic science, at the confluence of biology, geography, earth sciences, evolutionary theory, systematics, paleontology, climatology, and even molecular biology. 

مباحث کلاسی اکولوژی (1)

What Do Ecologists Study?

Response of organisms to the physical environment.

Interactions between species.

Limits to the number of individuals in an environment.

Controls on the rate of energy and material flows with a system.

The spatial and temporal scales on which process occur.

Consequences of adaptation to organism distributions and interactions.

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Define Ecology

study of the interactions that take place among organisms and their environment

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 Describe each of the following terms:

Biosphere

Biotic

Abiotic

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Ecological Organization via Krebs

“…the scientific study of the interactions that determine the distribution and abundance of organisms.”     (Krebs, 2001) 

مباحث کلاسی ارزیابی و اندازه گیری مراتع (1)

جدول: شماره، رنگ و كد استاندارد براي برخي از پوشش‌هاي گياهي

شماره	نوع تيپ پوشش گياهي	رنگ	كد Dixon
1	اراضي با پوشش گياهي از گراسها (غير از چمنزار)	زرد	353
2w	چمنزار مرطوب	نارنجي	334
2d	چمنزار خشك	نارنجي	324
3	پهن‌برگان چند ساله	قرمز لاكي	2/1 – 321
4	گياهان نيمه بوته‌اي خشبي مثل درمنه	قهوه‌اي	343
5	گياهان پهن برگ توأم با درختچه	سبز زيتوني	325
6	جنگلهاي سوزني برگ	سبز روشن	2/1 – 354
7t	جنگلهاي متراكم	سبز آبي	2/1 – 320
7	ساير انواع پوشش درختي	سبز آبي	2/1 – 320
8	اراضي عاري از پوشش مثل شنزارها و نمك‌زارها	بدون رنگ	---
9	اراضي با اجتماعات سرو كوهي	سبز چمني	2/1 – 325
10	درختان پهن برگ	قرمز صورتي	322
18	گياهان يكساله	قرمز آجري	---
20	اراضي زراعتي	قرمز	349
---	سطح آبها	آبي آسماني	320

 

شكل: نمونه‌اي از نقشه اداره مرتع

 

کتاب شناسایی گیاهان مرتعی ایران

 

معرفی کتاب

سياست‌هاي مرتعداري در ايران (گردآوري و تأليف: نگهدار اسكندري، عسگر عليزاده، فاطمه مهدوي- انتشارات موسسه تحقیقات جنگلها و مراتع کشور) (دانلود فهرست) 

محاسبه تولید (تمرین کلاسی درس ارزیابی و اندازه گیری مراتع)

- در مرتعی با استفاده از پلات ۲*۱ و با استفاده از روش آدلاید نمونه برداری شده است. در صورتی که مساحت کل مرتع ۱۲۵ هکتار باشد تولید در هر هکتار . کل سطح مرتع را به دست آورید.

بوته مرجع (۱): عدد آدلاید: ۴ و وزن واقعی ۳۵ گرم- بوته مرجع (۲): عدد آدلاید ۵ و وزن واقعی ۵۱ گرم- بوته مرجع (۳): عدد آدلاید ۲ و وزن واقعی ۱۵ گرم- بوته مرجع (۴): عدد آدلاید: ۱ و وزن واقعی ۹ گرم- بوته مرجع (۵): عدد آدلاید: ۶ و وزن واقعی ۵۵ گرم

وزن دسته علوفه واحد ۷ گرم

عدد آدلاید در پلات‌ها عبارت است از: ۶-۹-۸-۵-۲-۳-۷-۴-۳-۵-۳-۲-۲-۶-۸-۵-۴-۱-۳-۷-۵-۴-۶-۹-۱-۲-۳