Ecology

Population Growth

https://en.wikipedia.org/wiki/Logistic_map

Keystone Species Concept

https://en.wikipedia.org/wiki/Keystone_species#cite_note-paine1969-1

HHMI documentary: https://www.theserengetirules.com/

Mass Effect

Zonneveld (1995) "Vicinism and mass effect" https://onlinelibrary.wiley.com/doi/pdf/10.2307/3236244

Abstract: The term vicinism (neighbourship), first published in a phytosociological context by Nordhagen, refers to the occurrence of plant species in a less favourable environment ‐outside their sociological (ecological) amplitude — as a result of the continuous supply of propagules from neighbouring areas. In recent studies on this subject the term mass effect has been used for what seems to be the same phenomenon. This is unfortunate since this term was introduced much earlier to indicate the ability of plants which are able to grow in dense stands in order to change the local environment to the benefit of themselves — physically, chemically or mechanically‐ by developing a dense vegetation cover. Examples of this mass effect are mainly found in extreme environments such as salt marshes and lake shores. The occurrence of both vicinism and mass effect indicates that competition is not the only biological factor important in selection. Vicinism also contributes to connectivity, a major topic in landscape ecology. Both vicinism and connectivity as synecological concepts in their original meaning deserve more attention from ecologists.

Kunin (1998) "Biodiversity at the edge: A test of the importance of spatial “mass effects” in the Rothamsted Park Grass experiments" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC18177/

Abstract: The coexistence of many plant species competing for a few resources is one of the central puzzles of community ecology. One explanation is that different species may be competitively superior in different microhabitats. Many species could then coexist within each piece of a mosaic landscape by what has been termed “mass effects,” because subpopulations in areas with negative growth rates would be supplemented by propagules from areas with reproductive surpluses. If mass effects are important, plant species diversity should increase near habitat boundaries, especially where habitat differences are moderate. In the first experimental test of this prediction, plants were censused on 54 transects within the long-established Rothamsted Park Grass plots. Very few showed significant declines in species richness with distance from subplot boundaries. Nonetheless, the regression coefficients were negative much more often than expected by chance, suggesting that weak mass effects operated. The effect was strongest where neighboring subplots differed greatly, with no evidence of the predicted decline where differences were extreme. Detailed analyses of transects with apparent mass effects revealed few species that behaved as predicted. This study serves both to provide evidence of the existence of mass effects and to question their importance in the maintenance of local plant diversity in this system.