[] These models are then tested in the laboratory and the field. Usually ecosystem studiesproduced detailed analyses of nutritional or climatic requirements ofparticular communities. The end of the drought caused an increase in vegetation, and particularly pinon nut production. Ecosystems are dynamic entities that are subject to a variety of abiotic and biotic disturbances. Only the energy that is directly assimilated into an animal’s consumable mass will be transferred to the next level when that animal is eaten. It remains the case thatthese questions can often easily be answered using traditionalmathematical models: an ounce of algebra may well be worth a ton ofcomputer simulation. This trivial and obvious ecological factcannot be explicitly represented using the standard resources of anyGIS package (that is, it cannot be represented without writing specialprograms). A detrital food web consists of a base of organisms that feed on decaying organic matter (dead organisms), called decomposers or detritivores. But this choice of representation hasits costs: the mode of representation which is at the core of GISmakes it “natural” to represent systems in such a way thatcertain types of relationships tend to get lost, or at least relegatedto the background, while others receive emphasis. Resilience is the speed at which an ecosystem recovers to equilibrium after being disturbed. Such testing allows scientists to make sure that the values predicted by the model are similar to Figure 1.4 Ecologists use data

Ecologists can make predictions using ecological models. Withinspatial ecology these were represented as entities having spatialrelations with each other, besides the traditional ecologicalrelations defined by their interactions.
f, observe. On theone hand, it is obviously environmental because floods are preciselythe type of mechanism by which environmental stochasticity isexpressed. External factors, such as climate and the parent material that forms the soil, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. While the resource inputs are generally controlled by external processes, the availability of these resources within the ecosystem is controlled by internal factors such as decomposition, root competition, or shading. Some ecologists study ecosystems using controlled experimental systems, while some study entire ecosystems in their natural state; others use both approaches.

t. Producers release carbon dioxide into the atmosphere during the process of photosynthesis. At each trophic level, most of the energy is lost through biological processes such as respiration or finding food. These simulations are considered to be the most accurate and predictive of ecosystem dynamics.Scientists use the data generated by these experimental studies to develop ecosystem models that demonstrate the structure and dynamics of ecosystems.

f, condenses. A major limitation to these approaches is that removing individual organisms from their natural ecosystem or altering a natural ecosystem through partitioning may change the dynamics of the ecosystem. Centralphilosophical problems include explication of relevant notions ofecological diversity and stability the relation between diversity andstability. Thus any defense of reductionism in ecology basedon IBMs must be very limited.The science of ecology studies interactions between individualorganisms and their environments, including interactions with bothconspecifics and members of other species. From one year to another, ecosystems experience variation in their biotic and abiotic environments. Ultimately, as willbe discussed below in some detail, whether this is a case ofdemographic or environmental stochasticity depends on how it ismodeled. Holistic Ecosystem Model. Consequently,classification is not theoretically innocent. A drought, an especially cold winter, and a pest outbreak all constitute short-term variability in environmental conditions. More attention willbe paid to stochastic models which raise much more interestingphilosophical issues that have not been adequately explored.Nevertheless, what is somewhat philosophically troubling about the useof GIS in ecology is the conceptualization and representation ofgeographical information as: (a) a linked set of places, linked in thesense that the places must maintain fully precise adjacency relations;but (b) an unlinked set of attributes (for instance, the presence orabsence of species or other biological features).