Anticipating climate Change
Grasslands currently store approximately 34% of the worlds terrestrial
carbon, making these ecosystems important carbon sinks and play a
critical role in climate change mitigation (Contant, 2010). Carbon
sequestration is achieved by grassland vegetation holding organic carbon
within their roots, therefore higher sequestration is found in less
disturbed grasslands with long lived perennial grasses that develop
dense root systems (Acharya et al ., 2012). This suggests that
long term management of grasslands will likely provide greater climate
regulation. Carbon sequestration has been observed to improve with good
management techniques, particularly the addition of nitrogen fixing
plants (De Deyn et al ., 2011), addition of fertilizers and lime
(Acharya et al ., 2012) and withholding excessive grazing (Ezeet al ., 2018). Further, grasslands are essential for human food
security and provide an income for approximately 1.3 billion people
around the world (Suttie et al ., 2005). Livestock grazing
utilizes 80% of the total agricultural land and contributes to 40% of
global agricultural production (Suttie et al ., 2005). It is
predicted that demands for animal-based proteins and dairy are only
going to increase as a result of projected population growth (O’Mara,
2012), making functioning grasslands critical for providing adequate
nutritional resources.
Accelerated climate change adds a further element of complexity for
managing restoration projects into the future. It is expected that for
every 1OC increase in air temperature, there will be a
1.5OC increase in soil temperature (Ooi et al .,
2011), which may also cause disruptions to the seedbanks of many plant
species. Temperature has proven to be an important environmental factor
for breaking seed dormancy and these increased temperatures could
influence these important physiological processes (Ooi, 2012; Prosottoet al ., 2014). Further, atmospheric CO2 has
steadily risen from 325ppm recorded in 1970 to 405ppm in 2017 (Lindsay,
2018), and this is expected to approximately double by the end of this
century (IPCC, 2019). Enhanced atmospheric CO2 can
result in higher saturation of CO2, potentially reducing
photorespiration in C3 plants, even under a warmer
climate. This increased physiological efficiency has been demonstrated
to alter dynamics between C3 and C4plants (Dukes, 2000). As a result of these physiological improvements,
such as increased water-use efficiency (Varga et al ., 2015),
plants can allocate more resources to growth and fecundity and these
changes have also been observed to be more pronounce in weeds than
natives or crops (Marble et al ., 2015). Changes in extreme
weather patterns is expected to increase as a result of human induced
climate change. Compared to pre-industrial data, changes in the
intensity and pattern of rainfall events are already being noticed
(Power et al ., 2017). Changes in rainfall have direct
consequences on the intensity and frequency of fire, drought and flood
events (Ooi, 2012). As these factors play an important role in shaping
the vegetation of ecosystems and agroecosystems, new challenges for
managing native and weed competition dynamics can be expected.