Stratification is the layering of habitats within an ecosystem with the presence of distinctive physical and biological boundaries between the strata (layers). For example, in a temperate deciduous forest, you typically have 5 vertical layers: the canopy layer, the sapling layer, the shrub layer, the herbaceous layer, and the moss layer. Similarly, the stratification of a lake typically has three distinct layers: the Epilimnion (top layer), the Metalimnion (middle layer; may change depth during the day), and the Hypolimnion (the bottom layer). As such, ecosystem stratification is dependent on the ecosystem (e.g., the stratification of a forest is different than the stratification of a lake). Furthermore, ecosystem stratification does not only occur vertically, but can occur horizontally within an ecosystem as well.

Jeff--thank a lot for your valuable explanation. it is clear and very helpful. Thanks

the strata of ecosystem representative of the ecosystem structure that can be seen vertically or horizontally . for forest ecosystem-Vertical strata commonly refers to vegetation stratification as mentioned by Sir Jeff-- or overstorey-understorey layering, it also can be stratified as autotrophic (photosynthetic/produces) zone -heterotrophic zone (non-photosynthetic/consumer and decomposer) ; at the forest floor is also divided into necromass (woody debris-litterfall) layer, partially decomposed layer, humus layer, and so on. Each layer represent type of habitat, therefore the more complex is the strata the more species diversity found within the area. The complexity of strata also facilitate niche and resource partitioning diversity. Horizontally, the strata is representative of spatial distribution: opening, canopy, and edges.

Jeff and Sulstiyowati, thanks both of you a lot.

I also approached my friend who work on this field and he explained as follows:

"Strata is Groups or units defined by statistical classification, in the case of bioclimatic stratification the units are homogeneous units of ecological (plant) and climate data. Stratification does not result in recognizable biomes or ecosystem types, rather strata partition variation in independent variables for statistical inference." Thus, what do you think about this explanation? It is a bit hard to understand for me.

Dear Vanna, as you understand already that an ecosystem is a result of structure, processes, and function where the biochemical cycles and energy flow are connected each other. So it is a dynamic complex system involved many components both biotic and abiotic. Dont be confused, as an system there are many point of views or approaches to figure out the strata of ecosystem. The important thing is what do you want to study at certain ecosystem. Let say forest succession, so the changes of vegetation structure vertically or horizontally are important data or information; if do you want to get information of food web, the trophic or food levels (where biotic components involved) are important information; do you want to study abiotic strata so you will deal with variability of temperature, sunlight penetration, air moisture, or so on horizontally or vertically or toposequence within the ecosystem; do you want to get information of forest floor you could dig up a soil pedon and see the horizon layers (including physical, chemical, or biophysical characteristics); and so on. So what do you like to study now?? your objectives or target outputs should be coherence with your methodology or approaches. I hope it will helpful and not make you more confused