Has ecology grown up?

Figures & data

Figure 1. The scientific method according to Peters (1991).

Table 1. List of ecological principles proposed by Grubb (1989) and the present author’s comments.

	Principle	Comment
1.	A population must meet limitation of resources if not limited by predation, disease or other deleterious environmental factors (Malthus 1798).	Seldom cited by ecologists but often implied (Turchin 2001)
2.	One biotype will replace another under a given set of conditions if it has a greater fecundity or lesser mortality (Darwin 1859).	Self-evident? But the set of conditions is never constant.
3.	Two biotypes which are not permanently subject to rarefaction by some third party or other environmental factor can co-exist indefinitely only if they have different niches or are subject to greater intraspecific competition than interspecific (Gause 1934).	Species do co-exist in the same location for long periods i.e. they have the same habitat niche but they may differ in life form niche, phenological niche or regeneration niche (see Grubb 1977 and papers on Hubbell’s unified neutral theory e.g. McGill 2003)
4.	A prey and its predator can only co-exist in a heterogeneous environment (Huffaker 1958).	Based on one microcosm experiment (albeit an elegant one). Every environment is heterogeneous, so there are far-reaching implications of this principle.
5.	Density-dependent effects may (i) stabilise population size (ii) produce cycles, or (iii) produce chaos depending on the extent of non-linearity of the relation between Nt and Nt-1 (May 1974).	Important mathematical derivation; an ultimate cause of ecological dynamics.
6.	Available energy decreases at each stage of predation (Lindeman 1942).	Follows from the First Law of Thermodynamics.

Figure 2. The diffusion of ecology and ecologists into related areas of activity.

Figure 3. Citation trends obtained for articles published in 1990, using the search words ‘genome’ (open circles) and ‘ecology (closed circles). The search included all journals on the Web of Science (core collection).

Figure 4. Trends of citations for ‘ecology’ papers published in a basket of five top ecological journals in 1990 (closed circles), 2000 (open circles) and 2010 (closed triangles). The journals used in the search were Ecology, Functional Ecology, Journal of Animal Ecology, Journal of Ecology and Oikos.

Figure 5. The incidence of articles containing certain key words, obtained by searching the Web of Science for 1990 (black bars) and 2018 (grey bars). The journals are: JE, Journal of Ecology; OIK, Oikos; ECO, Ecology; JAE, Journal of Animal Ecology; FE, Functional Ecology.

Figure 6. Free-Air CO₂ Enrichment experiment (FACE) on mature oak forest (160-year-old Quercus robur). There are six 30 m-wide rings of fumigation-masts, three control and three elevated CO₂. In the centre of the picture is a meteorological and CO₂ observation tower. Birmingham Institute of Forest Research (BIFOR), University of Birmingham. Photographic credit: Norbury Estate.

Figure 7. Distribution of CO₂ flux sites 2018 (Burba 2019).

Figure 8. Percentage of all articles in Nature or Science that contain the words ‘ecology’ (black bars) or ‘genome’ (grey bars) from 1961 to 2018.

Box 1. CO₂ and Biosphere 2

A huge closed structure known as Biosphere 2 was built in the Arizona desert between 1987 and 1991, originally intended to see whether volunteer human inhabitants could co-exist with nature in a closed ‘bubble’. It was to be the model for future colonisation of planets outside of the Earth. Planted up using local soil, it contained desert, rainforest, savanna, thorn-scrub, mangrove–marsh, coral reef–ocean ecosystems and agriculture. The ecosystems were coarse approximations of real ecosystems but better than others had done before. The tropical section was stocked with numerous species, on the advice of the Director of the Royal Botanic Gardens, Kew. However, the project failed. Technical, psychological and management issues prevented the human-orientated work from being completed. There were some useful outputs: insights had been gained into the biogeochemistry of soil and important lessons were learned regarding the establishment of closed systems for the exploration and colonisation of space. Then, with new management and fresh perspectives, the facility was put to use in a more focused way to address questions relating broadly to climate change (Marino and Odum 1999). Later the new Research Director saw the facility as an ideal tool for up-scaling research at the small scale (often leaves) to the ecosystem (Osmond et al. 2004). The project went on to produce some 290 publications, covering a range of climate-change phenomena including, for example, the impact of drought on the emissions of volatiles (Pegoraro et al. 2007) and the impact of elevated CO2 on tropical rain forest (Lin et al. 1999). In Lin’s study the CO2 uptake by the rain forest was greatly enhanced in a short-term experiment. However, these ecosystems were still being judged as ‘artificial’ and true replication was not possible (as the traditional funding agencies were quick to point out). Moreover, Biosphere 2 lacked herbivores and levels of UV radiation were near-zero. Some ecologists viewed these ecosystems as merely man-made caricatures of nature.

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