Introduction
Temperate grasslands once covered almost 9 million
km2, which is equivalent to about 8% of the earth’s
surface (IUCN, 2013). They include the Prairies of North America, the
Pampas of South America, the South African Veldts, the Tussock
grasslands of Australia and New Zealand, and the Steppes of Eurasia
(Table 1). These biomes are often species rich (Faber-Langendoen &
Josse, 2010), providing natural habitat for many plants, animals and
soil biota. In addition, these grasslands offer invaluable ecosystem
services such as high-quality forage for herbivores (Boval & Dixon,
2012), harbour pollinators for crops and native species (Bendel et
al ., 2019), provide significant levels of carbon sequestration (Ezeet al ., 2018), and are places for many recreational and cultural
activities (Gomez-Limon & de Lucio, 1995). They also afford many other
environment stabilizing services, such as soil erosion control and
mitigation of flood waters (Sankaran & Anderson, 2009).
Given the significance and contribution of this ecosystem, they’re
currently one of the most altered ecosystems in the world (Suttieet al ., 2005), warranting immediate action to restore these
beneficial services. Estimates suggest that 70% of these ecosystems
were altered or degraded before 1950, and a further 14% by 1990 (Hassanet al ., 2005). This decline in ecosystem health is directly
attributed to rapid population growth and subsequent urban expansion
(Williams et al ., 2005), as well as the concomitant conversion of
these fertile ecological systems into sites for agriculture,
particularly for cropping systems and livestock grazing (Martin et
al ., 2005; Prober et al ., 2005; Bartolome et al ., 2009;
Sankaran & Anderson, 2009). While increased protection of the remaining
intact system is critical, it is not enough to ensure the future
resilience and functionality of these systems. Therefore, this paper
reviews restoration methods, both active and passive, that reduce
invasive plant biomass within global degraded temperate grasslands to
promote the return of natives and subsequent ecosystem functionality at
a landscape scale.