The lesser kestrel Falco naumanni and the European roller Coracias garrulus are both avian species that require cavities to be able to nest. In their Portuguese stronghold they nest mostly in cavities in abandoned rural buildings and artificial nest sites. The buildings in which they nest are slowly collapsing, making artificial nest sites an increasing requirement. Both species are on their way to becoming conservation reliant (Gameiro et al., Reference Gameiro, Franco, Catry, Palmeirim and Catry2020).
In a series of influential papers the authors of Shepherding Nature laid out the concept of conservation reliance. In Shepherding Nature they expand their argument and provide the following definition of conservation reliance: ‘A species is conservation reliant if it is vulnerable to threats that persist and requires continued management intervention to prevent a decline toward extinction or to maintain a population’ (p. 3). The term is not binary but rather dynamic, changing with threats, conservation actions and the biology of the species. The concept has its roots in the 1994 version of IUCN's Red List but was dropped in 2001.
For too long the conservation community has operated under a little-examined assumption that somehow when a previously threatened species was fully conserved it would not require further conservation actions. And how wrong we have been. In the USA, for example, some four-fifths of the species listed as Threatened or Endangered under the Endangered Species Act are conservation reliant. Similar figures for other countries have not been calculated.
Shepherding Nature is a book with 11 chapters that details the circumstances, stories and strategies of conservation reliance. Its chapters cover existing threats, emerging threats, policy and law, and species conservation tools. Throughout the book are scattered some 11 ‘essays’: short case studies written by outside experts, some of which strongly carry the narrative forward and others less so. The well-known stories of the California condor, Hawaii's native forest birds and Kirtland's warbler provide both the basis and the powerful illustration of how and why conservation reliance comes about. The book finishes with a prioritization framework for action to conserve species. The book is mostly about the USA, the country where all authors reside; where it does cross national boundaries, it is largely to other English-speaking countries, particularly Australia and New Zealand.
In many ways the book is more about general species conservation than just conservation reliant species. Although this may have been necessary, it dilutes the power of the concept as it reviews a good deal of basic conservation biology that will be well known to many readers. Shepherding Nature is situated in the core of traditional species conservation and conservation biology. It pays only slight attention to the larger forces that suggest to many of us that traditional conservation and its traditional tools may not be enough to address the future of nature in a human-dominated world. A recent study by Ceballos and colleagues (Reference Ceballos, Ehrlich and Raven2020) shows that c. 94% of the populations of 77 mammal and bird species on the brink have been lost in the last century. Conservation reliance is here to stay. And in the end the challenge for humanity is to realize that we, ourselves, are a conservation reliant species.
