223(e) Consider how many species are required for a managed system
Identifying the required number of species is not straightforward. From a man-
agement perspective, fewer rather than more is an attractive proposition but, from
the animal’s perspective, a diversity of forages can stimulate appetite and feed
intake (Agreil et al. 2005 , Meuret and Provenza 2015a). In most cases, about two-
thirds of the diet of grazing herbivores is made of up 3–6 species, with a large num-
ber of species (depending on availability) making up the remainder. Many species
might only be consumed in small amounts, but they might still be important to the
nutrition and health of the animals, and the health of the landscape (Vercoe et al.
2009 ). Therefore, focusing on only the 3–6 species that dominate consumption
could compromise animal performance.
(f) Consider the spatial arrangement
The optimal spatial arrangement of perennial shrubs will depend on the local
situation, and could range from high density ‘block’ plantations to ‘alley farming’
systems with large inter-row spaces.
(g) Provide socio-economic instruments that facilitate implementation
A critical issue is that transformation of a production system is likely to be a big
step for managers for several reasons, including social pressures to stay with the
norm, potentially high up-front costs, and a lag in profitability whilst the system
(plants, animals, people) becomes established.
(h) Adaptive management, adequate monitoring, and capacity to modify design
elements
A versatile production system must, by definition, be able to respond to external
events, so it must not be viewed as ‘the solution’ but rather as one set of options that
can be integrated into current practices, monitored and adapted as required.
A grazing system that incorporates a range of functional plant types can take on
many forms, but a common description is silvopastoralism, in which shrubs and
trees are combined with herbaceous forages. These systems promote vertical and
horizontal diversity – ie, diversity by volume, not just area, and span a broad range
of environments worldwide. In tropical and equatorial regions of Latin America,
such as in Columbia and southern Mexico, innovative silvopastoral systems are
being adopted (Murgueitio and Ibrahim 2008 ; Hall et al. 2011 ; Balvanera et al.
2012 ), with a mix of pastures, shrubs, trees and herbage, and the outcome has been
an increase in the growth rate in cattle (Paciullo et al. 2011 ). Silvopastoral systems
can be adapted to dryland climates (Guerra and Pinto-Correia 2016 ), such as
Northern Australia, where leguminous Leucaena spp shrubs have been planted as
extra food for cattle (Dalzell et al. 2006 ). In addition, cattle and sheep have been
supplemented with tagasaste (Chamaecytisus palmensis Christ.) in low fertility,
sandy soils (Borens and Poppi 1990 ; Becholie et al. 2005 ; Assefa et al. 2008 ) and
saltbush (Atriplex spp.) in saline land (Norman et al. 2004 ; Barrett-Lennard and
Norman 2009 ; Masters et al. 2010 ). These shrub-based strategies give better results
Integrated and Innovative Livestock Production in Drylands