Ecology Curriculum Manual - an overview

The aim of this collaborative activity is to devise a globally applicable curriculum for teaching ecological science (Ecology with a capital E) in higher education. The reasoning is provided elsewhere (REF to Dormann & Mello 2022), but the important bit for this page is that we need to define what goes in, and what stays out. We need to transparently state purpose and logic of our guidelines, how to contribute to the Ecology Curriculum itself. That is the task of this EC Manual.

Principles of putting together the Ecology Curriculum

Ecology textbooks are thick. This is partly because the range of ecological topics is vast, and partly because Ecology is taught through examples and case studies. A curriculum will have to strip this to a bare minimum, following the following principles:

• Clarity is of paramount importance. Define, and use consistently, all relevant terms. (Diversity, to name one example, typically means species richness, which in fact typically means species density. Such lack of clarity should be avoided, even if it means using “uncommon” language. Understanding is key, not words.)
• Laws are more important than patterns. (If more solar radiation leads, in some long causal chain of events, to more species, then the much-observed latitudinal gradient in species richness is “merely” a consequence of the “energy principle”. It is the principle that should be taught, and illustrated by the pattern.)
• The better understood should have precedence over the less understood.
• Aggregated, higher-level state variables are easier to understand and predict than lower-level ones.(Plant biomass per km² can be well predicted from precipitation and temperature, but plant species identity cannot, as it is contiguous on the species pool of the region.)
• Global principles are more relevant than local phenomena and anecdotes. (Darwin’s hawk moth pollinating a long-spurred orchid is a textbook extreme, but is highly non-representative of both pollination specialisation and coevolution. It is thus not relevant for the curriculum.)
• Elements included should be evidence-based, not folklore. (“Invasional meltdown” (Simberloff & Van Holle 1999) is a very catchy phrase and idea, but evidence does not support it as a general feature of introduced species (e.g. Yin et al. 2022).)
• The motivation of science is to understand processes in nature. Motivation by problems is engineering. (While individuals may be personally motivated by applied questions, such as conservation, this is not the motivation for science and hence Ecology in general. Also processes and patterns of no applied value are valid targets of ecological research.)
• Purely theoretical approaches should be relegated to optional classes, unless they are required to understand core elements. (The consequences of functional response of type III for predator-prey dynamics offer little qualitatively new insights of type II. So why teach them as core element?)
• Applied case studies should be relegated to optional classes, unless as illustration of underlying processes. (Ecological applications may be very important, e.g. in conservation, agroecology or forestry, but for teaching they would be either motivation or illustration. If a proposed treatment works but cannot be linked back to ecological laws, then what are students to learn from this?)
• Language should be value-free and measured. (Particularly conservation topics may use hyperbolic terms, such as “climate crisis” or “alien species”. That is not the language of science, and should be kept to a minimum.)
• Kill your darlings. (Keep text concise and succinct. Avoid reminiscing rambling and historical excursion.)
• Use British English. In particular, punctuation serves to improve readability, no matter what the rules are. (It’s like driving on the right or left hand side; there is no right or wrong, but everybody should do the same. BE is taught in more countries than AE, but probably more publications are in AE than in BE.)

Decisions on the level of student courses

BSc = undergraduate or MSc = graduate?

Quality assurance of contributed links to courses and material

Open in spirit, but also open in licence?

Making sure that contributed material can be used freely by everyone.

Glossary & Definitions

• abundance: absolute quantification of items: number of individuals, biomass, cover
• concept
• diversity: abundance-weighted species density (richness per area)
• evidence-based
• folklore
• law: a statement about a mechanism that is mostly true
• nature: the immediately experiencable part of the entire living and lifeless universe; thus nature includes humans;
• pattern
• principle
• state variable

References

Colyvan, M., & Ginzburg, L. R. (2003). Laws of nature and laws of ecology. Oikos, 101(3), 649–653. link

Dodds, W. K. (2009). Laws, Theories, and Patterns in Ecology. University of California Press, Berkeley.

Hutchinson, G. E. (1978). An Introduction to Population Ecology. Yale Univ. Press.

Lawton, J. H. (1999). Are there general laws in ecology? Oikos, 84(2), 177–192.

O’Hara, R. B. (2005). The anarchist’s guide to ecological theory. Or, we don’t need no stinkin’ laws. Oikos, 110(2), 390–393. link

Odum, E. P. (1953). Fundamentals of Ecology. Saunders.

Simberloff, D., & Von Holle, B. (1999). Positive interactions of nonindigenous species: Invasional meltdown? Biological Invasions, 1, 21–32.

Travassos-Britto, B., Pardini, R., El-Hani, C. N., & Prado, P. I. (2021). Towards a pragmatic view of theories in ecology. Oikos, 130(6), 821–830. link

Vellend, M. (2016). The Theory of Ecological Communities (Vol. 57). Princeton University Press. link

Yin, D., Meiners, S. J., Ni, M., Ye, Q., He, F., & Cadotte, M. W. (2022). Positive interactions of native species melt invasional meltdown over long-term plant succession. Ecology Letters, 25(12), 2584–2596. link

Theory

Even when relaxing the definition of “law” to allow minor deviations (following Dodds 2009), the question remains, whether Ecology has laws, and whether they are needed. Even if “we don’t need no stinking laws” (O’Hara 2005) for ecological science, we here argue that they serve one important point:

1. Didactically, laws structure the teaching of ecological theory. Introducing them, one by one, will make it easier for the teacher to build up a coherent curriculum, align case studies and methods, define spatial and temporal scales.
2. (The same applies to ecological research, which is of no immediate concern here.)

Ecological laws, or if you prefer: principles, were defined by different ecologists in the past, in particular with an ecosystem perspective (Odum 1953), a population perspective (Hutchinson 1978), to acknowledge their insufficiency as guidance for Ecology (Lawton 1999, O’Hara 2005), or as starting points and elements for deducing ecological theory (Dobbs 2009, Vellend 2016). The literature discussing these different points is diverse and confusing (and possibly confused: Colyvan & Ginsburg 2003; Travasso-Britto et al. 2021).

For the development of a curriculum, it may be useful to start somewhere and move on from there, following the guiding principles articulated in the introduction. With a more pragmatic definition of “law” (Colyvan & Ginsburg 2003), one can start with the 35 laws¹ proposed by Dobbs (2009). These are organised along a somewhat arbitrary but intuitive gradient of strictness and scale:

Foundations:

1. Laws from physics, chemistry and mathematics
2. Evolution and natural selection
3. Dominance of Homo sapiens

Fundamental biological laws:

1. Biological composition
2. System openness
3. Recycling rates

Physiological constraints of organisms:

1. All organisms die.
2. Energy requirement
3. Nutrient cycling requirement
4. Maximum metabolic rates
5. Water requirement
6. Temperature optimum

Behaviour of organisms:

1. Sensory integration
2. Predictability of behaviour

Fundamental properties of populations:

1. Conservation of individuals
2. Exponential growth
3. Limits to growth
4. Population stability not determinant
5. Extinction probability

Laws that arise from evolution

1. Biotic/abiotic interactions
2. Evolution affects ecology
3. Specialisation
4. Irreversibility of extinction

Variability and organisms

1. All organisms are unique
2. Population, resource and habitat heterogeneity
3. Scaling

Biotic and abiotic interactions of organisms

1. Species interact
2. All types of reciprocal interactions are possible
3. Diversity of interspecific interactions
4. Variance of interspecific interactions
5. Competitive exclusion
6. Linkage of interactions
7. Nonpropagation of interaction chains
8. Heterogeneity increases diversity
9. Diversity positively correlated with area

Additionally, Dobbs (2009) proposed some “candidate laws”:

1. All organisms have diseases (viral or otherwise).
2. Organisms will evolve the ability to tolerate, and likely metabolise, unique organic compounds
3. Non-equilibrium nature of life leads to non-equilibrium conditions in ecological systems
4. The law of failure (of other laws)
5. Consumer-resource oscillations as a law of populations

And he lists some law-like principles and generalisations that are mostly useful, if not laws: Liebig’s Law of the Minimum; Occam’s Razor; Shelford’s Law of Tolerance (or niche optimum); Costly traits have adaptive value; Allee effect; self-limitation of populations; occurrence of biomass pyramids; law of exergy (or ecosystem development towards maximum energy storage/dissipation); the Earth’s organisms evolved towards climate regulation (Gaia).

Classics

Methods

A rather fundamental distinction in methods is between those used to generate information (measuring, manipulating, experimenting, collecting, counting) and those extracting information from data (in silico methods, including statistics, computation, processing, calibrating, correcting).

For both types, a curriculum should focus on those methods that are relevant for addressing ecological questions, rather than biological, taxonomic or economic ones.

Measuring

Measuring abiotic conditions (temperature, pH, wind speed, salinity, pollutant concentrations, …) is a crucial element of ecological measuring, too, but not the target of an Ecology curriculum.

• Size of pool of target: mostly densities of organisms (vulgo: abundances in a given area, biomass, cover), but also pool sizes of resources (N, P, H2O, etc.): distance sampling, point counts, remote sensing, nesting aids, couter counter, …
• Identification of species (keys) and individuals (e.g. camera trapping)
• Densities of species (vulgo: species richness, diversity)
• Strength of flux: e.g. frequency of interaction, number of affected individuals, biomass fluxes in ecosystems

In Silico

As before, this is not about statistics, but about computer-based methods specific to ecology. Maths, statistics and programming are useful skills in many disciplines and should augment ecological teaching, too.

• controling for incomplete sampling (species richness estimation, rarefactioning, phylogenetic autocorrelation)
• estimating densities, population sizes, growth rates and alike from measurements
• analysing monitoring data (patch-occupancy models; state-space models)
• simulating growth, interactions, mortality, migration of hypothetical communities
• simulating fluxes across compartments of hypothetical ecosystems