**3.2 Importance of grasslands for grazing animals**

Grasslands can be classified as natural and improved grasslands. Natural grasslands are dominated by native grass species mixtures that occur naturally, while improved grasslands are developed by seeding and vegetative propagation of selected grass species [20]. Grasses form a basal diet for both livestock and wildlife animals that make livestock production in the traditional sector and the most protected areas for wildlife to rely on [21]. This situation leads to Livestock-wildlife competition that operates through two sets of processes within the social-ecological systems and economic processes that influence Livestock and wildlife-based enterprises as sources of income for people and the nation, respectively [20]. The authors considered that ecological processes affect the relative efficiencies of livestock and wildlife species in utilizing grasslands' feed and water resources. As a result, the contribution of livestock enterprises to people's livelihood generally exceeds the contribution of wildlife conservation to the livelihood of people within the same area [22]. Further studies show that economic processes result typically in agricultural returns to outcompete wildlife returns and the patchwork of land use within rangelands intensifies towards

#### *Interaction of Grassland Ecosystem with Livelihood and Wildlife Sustainability: Tanzanian… DOI: http://dx.doi.org/10.5772/intechopen.101343*

croplands and fragmented rangelands [22, 23]. This scenario corroborates observations made in the grasslands of Tanzania, as shown in **Figure 7**.

Population trends in **Figure 7** indicate that livestock increased continuously from 1995, possibly due to an increase in demand for livestock products that resulted from the increase in the human population. It has been reported that there is a close relationship between increases in cattle and growth in the human population that result from the need for livestock products to cater to the growing human population [26]. However, livestock in grasslands increases typically at the expense of wildlife [26]. Many studies show that markets, technology, and infrastructure development, the position of a rangeland/grassland on its production possibility frontier (PPF), changes with agricultural production becoming specialized, driving down the possibilities for wildlife production [27–31]. The overall population trend of grazers in the grasslands of Tanzania indicates a steady increase in the population [32]. This implies an increase in grazing pressure in grasslands that entails the need for close monitoring of the grasslands of Tanzania for sustainable livestock and wildlife production [8].

Frequent and severe droughts in many parts of Tanzania are being felt with their associated consequences on food production and water scarcity, leading to food shortages and insecurity, water scarcity, hunger, and it provides poor forage for animals [33]. Prolonged drought is a significant driver of grassland ecosystems and is likely to lead to increased wildfires and loss of wetland habitats that are critical habitats for migratory bird species and species migration and habitat shifts [34]. An increase in temperatures, reduced rainfall, and drought is already being observed in some regions of Tanzania [35]. In particular, the northern part of Tanzania-central Serengeti grassland is projected to become even drier in this century [36]. In wetter areas, forests are likely to encroach on existing grasslands. In contrast, deserts are projected to expand in extent and move upward in elevation in increasingly arid areas, causing "desertification" of arid grassland ecosystems. Such a process will greatly affect the productivity of the grasslands ecosystem, impacting animal welfare [35, 36].

### *3.2.1 Natural grasslands*

Survival of wildlife in protected areas and livestock production in the traditional sector in Tanzania rely on grasslands dominated by native grass species. The native grass species provide a basal diet for both wildlife and livestock herbivores. Native

#### **Figure 7.**

*Large Herbivore Units (LHU) population for livestock and wildlife in grasslands of Tanzania (source: Authors' computation based on TZFAOSTAT\_data [24, 25]).*

grass species inherently vary in biomass and nutrient contents they supply to the grazing animals. This compels wildlife and livestock to select certain grass species when grazing to meet their energy and nutrient requirements [37]. For a grass species to be consumed by grazing animals, it must belong to edible plant species (i.e., not harmful). Among edible plant species, some species are highly desirable, desirable, and less desirable. Plant species that are not edible are termed undesirable plants in terms of grazing animals' feeding value [37]. The natural grasslands of Tanzania are mainly composed of desirable and highly desirable grass species (**Figure 8**). This composition supports the survival of large numbers of grazing wildlife and livestock in the country.

Nutritive value of grasses in natural grasslands vitiates in quality rapidly across months within a year (**Figure 9**). This makes it rather difficult for natural grassland to support the high productivity of grazing animals throughout the year. High grazing animal production and products follow periods of high quantity and quality of grasses in grasslands [39]. In other words, there is natural synchronization of the reproduction cycle such that most of the calving occurs during periods of high quantity and quality of grasses in natural grasslands [39].

#### *3.2.2 Improved grasslands*

Improved grasslands in Tanzania are classified according to usages, such as pasture production farms for haymaking and grazing farms for dairy production. These farms are seeded with improved grass species: *Chloris gayana*, *Cenchrus ciliaris*, *Pennisetum purpureum*, *Panicum maximum*, *Setaria sphacelata*, *Tripsacum laxum* and improved varieties of Brachiaria species. In some cases, leguminous species are over-sowed in grass farms to improve the quality of hay. Common leguminous species mixed with grass include *Desmodium uncinatum*, *Centrosema pubescens*, *Macroptilium atropurpureum*, *Stylosanthes guianensis*, *S. guianensis*, *Pueraria phaseoloides*, *Clitoria ternatea* and *Calopogonium mucunoides*.

A considerable amount of work for improved grassland was carried out in Tanzania at Kongwa Pasture Research Centre with large-scale sowing of *C. ciliaris* under large-scale management [40–42]. Material initially selected in Tanzania was much more widespread use outside the country: common cultivars of tropical

#### **Figure 8**

*The desirability of grass species in western Serengeti natural grassland. Source: Authors' computation based on Kavana et al. [38].*

*Interaction of Grassland Ecosystem with Livelihood and Wildlife Sustainability: Tanzanian… DOI: http://dx.doi.org/10.5772/intechopen.101343*

#### **Figure 9.**

*Quantity and quality of grasses in Ugalla ecosystem's natural grasslands. Source: Authors computation from unpublished research data.*

pasture plants developed from Tanzanian material in Australia include *C. ciliaris* "Biloela", *C. gayana* 'Callide' and *Neonotonia wightii* 'Clarence' [43]. Mixing grasses with legumes is considered to increase dry matter production of grass. The highest dry matter yield of *C. ciliaris* was observed in a mixture with *Phaseolus atropurpureus*, *S. guianensis* and *C. pubescens* [44].

### **3.3 Contribution of grasslands to the livelihood of rural communities**

A direct result of the contribution of grassland to the livelihood of people and the national economy in Tanzania is that local people rely mainly on grassland for the production of livestock products. The trend of meat production from grasslands (**Figure 10**) shows that meat production increased at a decreasing rate, and the value of meat produced from grasslands increased progressively. This indicates that livestock keeping in grasslands is a lucrative business that contributes to rural people's economy. However, the contribution of meat produced from grassland to the total meat produced by grazing livestock showed a declining trend. This could be attributed to the decline in the potential of Tanzania's grassland of Tanzania to support large herds of grazing animals. The potential of grasslands to support grazing animals is affected by environmental fluctuations and increased human activities [45, 46]. Human population increase resulted in the expansion of cultivated land at the expense of grassland, and the need for animal products led to the keeping of large herds of livestock [26]. This situation causes shrinkage of grassland and overgrazing, reducing grassland's potential to support grazing animals in the country.

Grasslands contribute more than 60% of milk produced in Tanzania, and the value of milk produced increased steadily (**Figure 11**), contributing more than 2500 billion TZS to people's economy. However, the contribution of grassland to the total milk produced in Tanzania has been slightly increasing year after year [47]. This might be caused by improvement in urban dairy farming and probably deterioration of grasslands in terms of quantity and quality of feed resources availability in communal grasslands that need to be evaluated.

#### **Figure 10.**

*Quantity and value of meat produced from grasslands and other places of Tanzania. Source: Authors' computation based on livestock and fisheries basic data and Tanzania in figures 2016 documents.*

#### **Figure 11.**

*Contribution of grassland to milk production and economy of people in Tanzania. Source: Authors' computation based on Tanzania in figures document [47].*

#### **3.4 Challenges on the sustainability of grasslands**

Agriculture poses a significant challenge for the sustainability of grasslands in Tanzania. Current agriculture production is hinged on the expansion of monocropping farms to increase food production for the growing human population. In many cases, the expansion of crop farms is done at the expense of grasslands. Land clearing and cultivation for crop production re-structure and disrupts a previously stabilized grassland ecosystem. The disturbed ecosystem due to cultivation immediately begins succession where annual grasses and forbs adapted to bare land conditions and disturbed soil invade the site and become established. This situation results in changes in plant species composition of the grassland.

Grasslands are the main grazing areas for livestock where most of the grazing lands in the country are communally managed. Poor livestock grazing management results in soil compaction due to the effects of animal trampling, leading to poor water infiltration. Removal of plants due to many grazing livestock in communal

### *Interaction of Grassland Ecosystem with Livelihood and Wildlife Sustainability: Tanzanian… DOI: http://dx.doi.org/10.5772/intechopen.101343*

lands causes bare land (**Figure 12**). In combination with poor water, infiltration causes surface water runoff during the rainy season that erodes soil.

Soil erosion of bare land during the rainy season removes top fertile soil resulting in low soil fertility. Poor soil fertility causes the establishment of a limited number of plant species resulting in low plant composition on grassland. Low plant species composition leads to low above-ground biomass production that causes an insufficient feed resource base for grazing animals.

A high number of grazing animals in a shrinking grassland with an insufficient feed resource base in terms of quantity and quality results in high utilization pressure by grazing animals. High grazing pressure exerted on highly desirable and desirable grass decreases the potential of grassland to support grazing animals.

Effects of climate change on the grasslands of Tanzania could be manifested in relation to the variability of temperature and precipitation [8]. Climate change projections indicate that western parts of the country, central, north, Lake Victoria basin, eastern parts of Lake Nyasa, south-western and north-eastern highlands are projected to feature increased minimum temperature [48]. An increase in temperature is associated with an increase in the photosynthetic rate of plants under optimum soil moisture. Projections of precipitation indicate that Coastal regions, parts of north-eastern highlands, northern areas, western and southern parts of the Lake Victoria basin will experience an increase in annual rainfall. This implies that most of the grasslands of Tanzania are expected to increase Net Primary Production (NPP) of grass biomass. Therefore, the main limitations for the sustainability of most grasslands of Tanzania will be extensive crop cultivation and livestock population grazing.
