Biodiversity science has overtaken traditional ecological science in an important way that bears some discussion. Biodiversity science seeks as its main goal to protect species from declining to extinction. It overlaps traditional population and community ecology partly by concentrating on iconic species that are declining in abundance and thus trying to prevent species loss, but the major focus of biodiversity science is on the species composition of communities and ecosystems and trying to understand what factors are driving deleterious changes. This task is difficult to complete currently because of a shortage of research time, person-power and money, so we are driven to select relatively few ecosystems to concentrate our conservation efforts upon. If we cannot do everything for all species, we must choose what to do at the present time, and this releases a cascade of discussions and arguments about what species are ‘flagship’, “umbrella”, or “keystone” in any particular community or ecosystem (Barua 2011).

Now we can go in two directions. We can take the simplest route and say that all species are of equal importance, so the objective of biodiversity science becomes ‘occupancy” – is species X still existing in ecosystem Y? Occupancy can be established in a variety of ways from simple visual sightings, traps, cameras, e-DNA, to electronic sound recording devices. Occupancy for species in a particular ecosystem is a useful parameter for biodiversity studies but it is alpha-level ecology for understanding community or ecosystem dynamics. Determining occupancy every month, year, or decade will provide a start in community and ecosystem understanding but in order to achieve its goal as a science it needs population and community ecology to measure and understand the dynamics underlying occupancy, and this is the more complicated route that we can take. The defining science for this second level of understanding comes from dynamics, both population and community dynamics.

Population dynamics is necessary for determining if a particular species is declining in numbers or biomass, and what the causes are of the observed trends. We are led into demography, the measurement of births, deaths, and movements in animals and the equivalent parameters in plants. But now we run into the most serious problem of determining what parameters are the causal agents of declines in abundance and what procedures will alleviate species declines. If we have many species in our community or ecosystem, the requirements for research are extravagant, given the current workers and dollars currently available for environmental science. All ecologists want to protect biodiversity but how might we best achieve that goal?

We fall back at this point into simple general procedures for biodiversity conservation like designation of national parks or protected areas with the hope that the biodiversity of the designated area will not decline. We do not have the person-power to have frequent occupancy surveys for any national park, much less to have the investigations of why an iconic species is declining in an area. At present we must fall back on ‘umbrella species’ or ‘flagship species’ (Simberloff 1998). There is an extensive literature on this approach to biodiversity conservation and recent reviews, some critical (Tälle et al. 2023), others somewhat more positive (Sumbh and Hof 2022, Clark-Wolf et al. 2024), combining this approach with food web structure (Wang and Zhou 2023).   

Complicating the whole issue of protecting biodiversity is the issue of cryptic species, undescribed species, and rare species that are capable of taxonomic and ecological resolution but only at a large cost and a long timeframe to achieve results (Cheng et al. 2024). Once we are successful in protecting our communities and ecosystems, we immediately face the demographic issue of what affects the abundance of all the species of interest, and then the social and political issue of the funds available for conservation of these species. We need to bring the approaches of biodiversity science and classical demographic ecology together to achieve conservation goals. We can do this only by recognizing that knowing occupancy is not enough to achieve conservation success, and we need to follow up with population and community ecology within the context of food webs so that we can understand trends in abundance and finally propose possible actions for conservation management. We have much to do.

Barua, M. (2011) Mobilizing metaphors: the popular use of keystone, flagship and umbrella species concepts. Biodiversity and Conservation, 20, 1427-1440.doi:10.1007/s10531-011-0035-y.

Cheng, R., Luo, A., Orr, M., Ge, D., Houu, Z.e., Qu, Y., Guo, B., Zhang, F., Sha, Z., Zhao, Z., Wang, M., Shi, X., Han, H., Zhou, Q., Li, Y., Liu, X., Shao, C., Zhang, A., Zhou, X. & Zhu, C. (2024) Cryptic diversity begets challenges and opportunities in biodiversity research. Integrative Zoology, (in press). doi: 10.1111/1749-4877.12809.

Clark-Wolf, T.J., Holt, K.A., Johansson, E., Nisi, A.C., Rafiq, K., West, L., Boersma, P.D., Hazen, E.L., Moore, S.E. & Abrahms, B. (2024) The capacity of sentinel species to detect changes in environmental conditions and ecosystem structure. Journal of Applied Ecology, (in press). doi: 10.1111/1365-2664.14669.

Simberloff, D. (1998) Flagships, umbrellas, and keystones: is single-species management passe in the landscape era? Biological Conservation, 83, 247-257.doi: 10.1016/S0006-3207(97)00081-5.

Sumbh, O. & Hof, A.R. (2022) Can pikas hold the umbrella? Understanding the current and future umbrella potential of keystone species Pika (Ochotona spp.). Global Ecology and Conservation, 38, e02247.doi: 10.1016/j.gecco.2022.e02247.

Tälle, M., Ranius, T. & Öckinger, E. (2023) The usefulness of surrogates in biodiversity conservation: A synthesis. Biological Conservation, 288; e110384. doi: 10.1016/j.biocon.2023.110384.

Wang, Q., Li, X.C. & Zhou, X.H. (2023) New shortcut for conservation: The combination management strategy of “keystone species” plus “umbrella species” based on food web structure. Biological Conservation, 286, 110265.doi: 10.1016/j.biocon.2023.110265.