Global Patterns of Aquatic Food Chain Length
Craig Kelling, Chris Bieganek, Logan Mullen, and Trevor Cyphers
1.) What could some of the ways in which food chain length plays a role in regulating
biogeochemical fluxes, fisheries productivity, or contaminants bioaccumulation in top
predators be?
2.) In your opinion, does either the productivity hypothesis or the productive space
hypothesis do a better job of predicting productivity of an ecosystem?
3.) Tests of broad-scale patterns of food chain length have concluded that marine pelagic
ecosystems have the longest food chain lengths, and stream food chains are the shortest;
any ideas as to why this may be?
4.) Tukey – Kramer comparison tests indicated a difference in food chain length between
lakes and streams and streams and marine, but not between lakes and marine, why might
this be?
5.) Why might food chain length increase in ecosystems closer to the poles?
6.) Why would using stable isotopes provide better information for connectance webs or
food chain length in general?
7.) Given that tropical areas are more productive, why do you think lake and stream food
chains were longer at high latitudes when compared to the tropics?
8.) Why are marine food chains longer on average than both streams and lakes?
9.) What makes long food chains less stable?
10.) Highly resolved webs and poorly resolved webs may overestimate and underestimate
FCL for a given ecosystem. What would be an appropriate method for choosing the
importance of food web links in this manner?
11.) The paper discusses the effects of boundaries on food chain length. Can you describe
any additional scenarios in which the boundaries established for an ecosystem effect the
food chain length observed?
12.) Patterns of food chain length may result from multiple interacting factors. This
makes it difficult to identify a single determinant of food chain length. What do you
believe are the major factors involved with this issue?