Variation in food web structure has been linked to a variety of trophic level
and productivity patterns associated with freshwater communities (Carpenter et al.
"This increase can be propagated to higher trophic level
fish consumed by humans, resulting in increased human exposure to MeHg (methylmercury)," the researchers wrote.
Therefore, the intensity and frequency of rainfall events in the General Sampaio Reservoir during 2010 and 2011 cannot be classified as a high-intensity disturbance, but that might promote gradual changes in the trophic level
. These results confirm the hypothesis of Scheffer (2003) who stated that in the absence of disturbances (such as very low annual rainfall), limnological variables are minimally changed over the year.
By examining it, the scientists can determine what is called the "trophic level
" of each haddock, or its place within the food web hierarchy.
The authors assume high accuracy for theoretical predictors like molecular clocks and assignments of trophic level
. Vendian faunas are related to Cambrian faunas on wholly theoretical grounds, which may strike readers as the sort of "just-so story" maligned in older works.
Stable isotope data support the lipid evidence, and suggest that the majority of the 101 charred deposits, analysed from across Japan, were derived from high trophic level
The demise of one species or trophic level
(which contains organisms performing the same function in the food chain), leads to changes in others in a rapid sequence that is difficult to foresee.
[Note: Adding a representation of energy loss at each trophic level
, while important conceptually, would make the models unwieldy and confusing.]
(especially weedicides which were frequently used in wheat fields) than prey/pest species, because they directly depend on producers (wheat or weed plants) at the first or lowest trophic level
of the wheat agro-ecosystem.
Loss of larger cladoceran species can reduce grazing pressure on lower trophic level
phytoplankton which can induce algal blooms that may eventually disrupt the function of the ecosystem (Moss et al.
Variation in the whales' trophic level
(position in the food chain) was examined by using mass spectrometry to measure nitrogen isotopes in skin samples; enrichment of an animal's tissue nitrogen is known to occur as the animal eats higher on the food chain.
Leaf litter and deadfall have two primary functions related to small predators: (1) allowing them to acquire prey that live therein while (2) providing escape cover to avoid being preyed upon by species at a higher trophic level
, such as snakes, felids, and avian predators.