59
O.W. Van Auken and J.K. Bush, Invasion of Woody Legumes, SpringerBriefs in Ecology 4,
DOI 10.1007/978-1-4614-7199-8_9, © Springer Science+Business Media New York 2013
After examining what we have brought together here and what is presented in other
places in the published literature, it appears that understanding woody legume communities, including savannas and woodlands, is a diffi cult task. The results of a
number of experiments that are yet to be done are needed to fully understand these
woody legume communities and what will happen to them in a warmer, high CO 2
world. There seem to be many physical, chemical, and biotic factors involved. It
will probably be more diffi cult to manage these communities because many of these
savannas and woodlands were most likely grasslands at some time in the relatively
recent past. Consequently, understanding the interactions of the C 4 grasses and the
various woody legumes should be added to the mix of what is required to understand these communities. Thus, the task is complicated, but it is even more diffi cult
when relatively short-term temporal modifi cations (successional changes) and
small-scale spatial variability are added as factors that may further obscure the
understanding of long-term effects such as global climate transformations.
The invasion, or more correctly encroachment, of woody legumes into warm
season grasslands has happened all over the world. The grasslands can be various
types and seem to range from having moderate rainfall to dry-semiarid and arid;
thus, there seems to be a rainfall gradient involved. This process involving the
woody legumes really seems to be secondary succession, but not quite the classical
eastern North American farmland abandonment start of secondary succession.
Farmland abandonment could be the start and is in some cases, but usually one or
another species of woody legume encroaches (establishes) in the grassland and then
expands its population because of heavy and constant grazing and lack of fi re. The
environmental conditions present in past grasslands have changed; consequently
present-day grasslands are very different from what they were, and future grasslands will continue to adjust to the new conditions. A grassland community goes
through secondary succession after heavily grazing and no fi re. Changes seem to be
from grassland, to shrub land, to legume savanna, to legume woodland, and then to
possibly another type of nonlegume woodland or some other type of nonlegume
community. The last or later community in many cases seems undefi ned or unknown
Chapter 9
The Future
O.W. Van Auken and J.K. Bush, Invasion of Woody Legumes, SpringerBriefs in Ecology 4,
DOI 10.1007/978-1-4614-7199-8_9, © Springer Science+Business Media New York 2013
After examining what we have brought together here and what is presented in other
places in the published literature, it appears that understanding woody legume communities, including savannas and woodlands, is a diffi cult task. The results of a
number of experiments that are yet to be done are needed to fully understand these
woody legume communities and what will happen to them in a warmer, high CO 2
world. There seem to be many physical, chemical, and biotic factors involved. It
will probably be more diffi cult to manage these communities because many of these
savannas and woodlands were most likely grasslands at some time in the relatively
recent past. Consequently, understanding the interactions of the C 4 grasses and the
various woody legumes should be added to the mix of what is required to understand these communities. Thus, the task is complicated, but it is even more diffi cult
when relatively short-term temporal modifi cations (successional changes) and
small-scale spatial variability are added as factors that may further obscure the
understanding of long-term effects such as global climate transformations.
The invasion, or more correctly encroachment, of woody legumes into warm
season grasslands has happened all over the world. The grasslands can be various
types and seem to range from having moderate rainfall to dry-semiarid and arid;
thus, there seems to be a rainfall gradient involved. This process involving the
woody legumes really seems to be secondary succession, but not quite the classical
eastern North American farmland abandonment start of secondary succession.
Farmland abandonment could be the start and is in some cases, but usually one or
another species of woody legume encroaches (establishes) in the grassland and then
expands its population because of heavy and constant grazing and lack of fi re. The
environmental conditions present in past grasslands have changed; consequently
present-day grasslands are very different from what they were, and future grasslands will continue to adjust to the new conditions. A grassland community goes
through secondary succession after heavily grazing and no fi re. Changes seem to be
from grassland, to shrub land, to legume savanna, to legume woodland, and then to
possibly another type of nonlegume woodland or some other type of nonlegume
community. The last or later community in many cases seems undefi ned or unknown
Chapter 9
The Future