After coming across two interesting journal papers I thought they would make excellent case studies for my students. Let me introduce, and share, them with you.
The first case study deals with indicator species and the nitrogen cycle.
The paper by Aguillaume et al. (2017) is an observational study that collected data on lichen species and atmospheric ammonia concentrations around a cattle farm in Catalunya:
'A study was carried out in a holm-oak forest in NE Spain, 65 km away from Barcelona, and close to the Montseny Mountains. The forest surrounds a barn of ∼130 beef cattle, permanently housed in an area of 1500 m2. Air NH3 (ammonia) samples, and lichen samples on trees were taken at different distances from the barn to see the effect of nitrogen eutrophication on the surrounding environment.'
I've taken the graphical data from the paper and proposed questions to the students so they can interpret the findings.
Find the case study here.
The second case study deals with life strategies and energy investment.
It's about life strategies of plants, and the choices they make depending on their context. Should plants invest more in reproduction, growth, or maintenance. Should they invest in leaves, stem of flower? Well that depends on the context.
I like this topic, but I also like the study because the data is presented in an accessible way. The paper by Abrahamson and Gadgil (1973) observed the investment of Solidago species (Goldenrods) in leaf, stem, and flower, by measuring their biomass. They followed populations of the plants over before and during the flowering season in three different contexts:
Early successional: high mortality rate, but the plants did not grow densely enough to shade each other appreciably.
Mid successional: Moist meadow site, with dense growth of shrubs which shaded each other appreciably.
Late successional: Least disturbed with a low mortality rate, and tree climax species dominating. The plants were appreciably shaded by the trees, but they were sparse and did not shade each other.
Can the students predict which strategies would be favoured in different environments?
Can they interpret the data to find out?
Find the case study here.
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References
Aguillaume, L., et al. 2017. "The Critical Levels of Atmospheric Ammonia
in a Mediterranean Holm-Oak Forest in North-Eastern Spain." Water Air Soil Pollut 228: 93.
Abrahamson, W., and Gadgil, M. 1973. "Growth Form and Reproductive Effort in Goldenrods (Solidago, Compositae)." The American Naturalist 107 (957).