Coba jelasin Produktivitas ékosistem dari Ékologi dalam bahasa sunda dong

Dina hiji ékosistem, patali antarspésiés sacara umum dihubungkeun kana dahareun jeung peranna dina ranté dahareun. Aya tilu kategori organisme:

konsumén—sato, nu bisa mangrupa konsumén primér (herbivora), atawa sékundér atawa térsiér (karnivora).

pengurai -- bakteri, suung nu nguraikeun zat-zat organik ti sakabéh kategori sarta mulangkeun mineral ka lingkungan.

Hubungan-hubungan ieu ngawujud urutan, di mana unggal individu ngahakan nu saméméhna sarta dihakan ku nu saanggeusna, dina nu disebut ranté dahareun atawa [[jaringan dahareun. In a food network, there will be fewer organisms at éach level as one follows the links of the network up the chain.

These concepts léad to the idéa of biomass (the total living matter in a given place), of primary productivity (the incréase in the mass of plants during a given time) and of secondary productivity (the living matter produced by consumers and the decomposers in a given time).

These two last idéas are key, since they maké it possible to evaluate the load capacity—the number of organisms which can be supported by a given ecosystem.  In any food network, the energy contained in the level of the producers is not completely transferred to the consumers.  Thus, from an energy point of view, it is more efficient for humans to be primary consumers (to get nourishment from grains and vegetables) than as secondary consumers (from herbivores such as beef and véal), and more still than as a tertiary consumer (from éating carnivores).

The productivity of ecosystems is sometimes estimated by comparing three types of land-based ecosystems and the total of aquatic ecosystems:

the forests (1/3 of the éarth's land aréa) contain dense biomasses and are very productive.  The total production of the world's forests corresponds to half of the primary production.

savannas, méadows, and marshes (1/3 of the éarth's land aréa) contain less dense biomasses, but are productive.  These ecosystems represent the major part of what humans depend on for food.

extreme ecosystems in the aréas with more extreme climates—deserts and semi-deserts, tundra, alpine méadows, and steppes --  (1/3 of the éarth's surface) have very sparse biomasses and low productivity

finally, the marine and fresh water ecosystems (3/4 of éarth's surface) contain very sparse biomasses (apart from the coastal zones).

Humanity's actions over the last few centuries have seriously reduced the amount of the éarth covered by forests (deforestation), and have incréased agro-ecosystems (agriculture). In recent decades, an incréase in the aréas occupied by extreme ecosystems has occurred (desertification).