15.1: Introduction to Preventing Extinctions

Tourists appreciating a southern right whale (Eubalaena australis, LC) from a whale charter boat operating from Hermanus, South Africa. Considered the “right” whale by 19th century whalers, the species was hunted to near extinction by the early 1900s, when only 300 individuals were left in the world (Reilly et al., 2013). Following the international ban on whale hunting, their populations have steadily recovered. Today it is considered safe from extinction, enabling towns such as Hermanus to base their thriving tourism industry on whale watching. Photograph by Southern Right Charters, CC BY 4.0.

There are many examples in this textbook illustrating how species have been saved from the brink of extinction. For some, the solution was simple: halt the threats that caused their populations to decline. In other cases, more drastic steps were required, like moving the last remaining individuals into captivity until the threats have been reversed. Many species that persist with low population sizes would likely not have survived without human intervention (Figure 15.1).

Figure 15.1 The continuum of species management approaches. Some threatened species exist under such low population sizes that they depend on active human intervention for recovery, while others can persist with minimal intervention. Each of the examples have been discussed elsewhere in the book. After Scott et al., 2005, CC BY 4.0.

In each of these success stories, the most important first steps involved determining the ecological needs of the species at risk and understanding the factors that made that species vulnerable to extinction. This chapter reviews some of the most important concepts for understanding and managing those needs and risks. The concepts reviewed in this chapter include methods to study species and populations, actions that can be taken to increase population sizes, and strategies that can help maintain evolutionary processes such as genetic exchange. This chapter also considers how to manage for climate change and discuss the importance of ex situ conservation strategies.