Warmer, wetter climate would impair California grasslands
17-year experiment finds present climate near optimal for plant growth
September 6, 2016
Scientists said data from one of the world’s longest-running climate-change experiments show that California grasslands will become less productive if the temperature or precipitation increases substantially above average conditions from the past 40 years.
Results from one of the longest-running and most extensive experiments to examine how climate change will affect agricultural productivity show that California grasslands will become less productive if the temperature or precipitation increases substantially above average conditions from the past 40 years.
Pressures from grazers hastens ecosystem collapse from drought
Experiments show grazing pressures compound drought stress, delay recovery
January 11, 2017
Ecosystem collapse from extreme drought can be significantly hastened by pressures placed on drought-weakened vegetation by grazers and fungal pathogens, a new study finds. The study’s experimental evidence shows that the natural enemies of plants play a major role in lowering resilience to drought and preventing recovery afterward. The finding may be applicable to a wide range of ecosystems now threatened by climate-intensified drought, including marshes, mangroves, forests and grasslands.
A new study by scientists at Duke University and Beijing Normal University may hold the answer why.
The researchers found that these tipping points can happen much sooner than current models predict because of the added pressures placed on drought-weakened plants by grazing animals and fungal pathogens.
“Our work provides the first real-world experimental evidence that these natural enemies of plants can play a dramatic role in lowering ecosystems’ tipping point by killing drought-weakened vegetation and preventing plants from recovering,” said Brian R. Silliman, Rachel Carson Associate Professor of Marine Conservation Biology at Duke’s Nicholas School of the Environment.
Ecologists have long known that drought can stimulate this type of attack on plants, he said, but they mostly discounted it as a secondary stress and not a main cause of ecosystem collapse.
“What we found is the opposite,” Silliman said. “Grazers have a strong compounding effect. This means these ecosystems are far more vulnerable to drought than the current models predict. With grazers present, they can handle much less drought stress.”
Sourcing fodder poses a big headache to many dairy farmers. Brachiaria, a grass repatriated to Africa from Brazil, is good for grazing, can be baled as hay, and increases milk production.
Brachiaria grass is indigenous to Africa, but has been growing wild until recently. It was taken to other parts of the world, including Australia and South America, where it was improved to get superior varieties, some of which arc now being promoted in Kenya.
Rural households in Uzbekistan customarily invest into livestock as a secure way of savings. Surroundings of settlements and accessible watering points are normally used as grazing areas. However, unsystematic and excessive load on rangelands has led to strong processes of land degradation and put pressure on rangeland resources.
Rangelands in Uzbekistan are one of the most important life-supporting natural ecosystems. They occupy about half the country, nearly 25 million hectares, the bulk of which is located in the north – large parts of Karakalpakstan, Navoi and Bukhara regions, as well as south – Kashkadarya region. 80% of rangelands are located in deserts, with average annual precipitation of 100 mm, mainly used for karakul sheep, camel and goat breeding. Karakul sheep, the most well-suited for desert rangelands, make up about 4.5 to 5 million heads, mainly bred by ‘shirkats’ (collective farms) and households.
Like the entire region of Central Asia, Uzbekistan’s livestock production faces a number of challenges, despite support from the government and attention paid to improving production of livestock. Constraining factors are mainly limited resources of pasture and arable land for fodder production, whose state is further exacerbated by erratic rainfall and increasing summer temperatures in recent years. Increased demand for meat products due to population growth and income of urban residents indicate the need to consider a more environmentally conservationist approach for feed and livestock systems.
To address challenges like climate change and land degradation, ICARDA-led Knowledge Management in CACILM II project organized a round table on 18 March 2016, wherein rangelands experts, officials, members of parliament, farmers and local populations attended to discuss the state and prospects of rangelands development in Uzbekistan.
Restoring rangelands: A Namibian dream to come true
Namibia’s intention to restore its valuable rangelands at a whopping cost of some N$30 billion over the next 20 years is regarded by many observers as a groundbreaking project, which has earned the respect of role players at international podiums.
It is also viewed as an example of a government committed to the rehabilitation of degraded land and water bodies – to be at declining rates of degradation by 2030.
Chief rangeland researcher of the Namibia Rangeland Management Policy and Strategy (NRMPS), Leon Lubbe, updated attendants on the project at the recently held NNFU’s Leadership Seminar in Otjiwarongo.
He said the project was implemented in 2012 and is committed to the promotion and maintenance of the welfare of the people by adopting policies aimed at maintaining ecosystems, essential ecological processes and biological diversity, and utilizing living natural resources on a sustainable basis for the benefit of all Namibians, according to Act 95 (1) of the constitution.
Some 70 percent of the population is dependent on its rangelands for their well-being. The current poor state of Namibia’s rangelands is due to soil erosion, overgrazing, bush encroachment and a drastic decline of carrying capacity of the land.
This situation negatively Influences the livelihoods of a large portion of the Namibian nation, profitability of livestock farming and the whole economy in general (a possible N$1.4 billion/annum is lost).
It is expected that there will be a 30 percent drop in the production of course grains by 2030 in southern Africa and this highlights the important role of livestock in future.
Lubbe highlighted that measurements need to be taken to achieve the goals of the project, saying all the guiding principles of sound rangeland management will have to be implemented to secure success.
A study that evaluate the changing nature of pastoralists’ institutional arrangements in response to socio-economic and ecological changes over a period of 10 years, and assessed how these changing arrangements are contributing to value of ecosystem services benefits, shows that co-management is now a significant feature of current institutional arrangements in northern Kenya.
Three types of institutional arrangements including elders only, group ranch committees and community conservancy boards were reviewed. Results showed that management of the rangelands has changed over time and co-management is now positively influencing the economic benefits communities derive from these ecosystems and is enabling pastoralists to diversify their livelihoods as part of enhancing their resilience.
The study was carried out in Isiolo, Laikipia and Samburu.
Fred Segor, principal secretary in Kenya’s State Department of Livestock in the Ministry of Agriculture, Livestock and Fisheries and member of the board of trustees of the Kenya-based International Livestock Research Institute (ILRI), recently announced that a large government-sponsored livestock insurance scheme would begin being implemented this October in Wajir, Turkana and Marsabit at a cost of Kshs80.9 million (about USD800,000).
Fred Segor said the cover would be escalated to cover 14 of Kenya’s northern counties, targeting 5,000 households in the short term, to help them cope with recurring drought.
William Ruto, deputy president of Kenya, lauded this pastoral insurance initiative, noting that it was a culmination of intense research by the Kenya Ministry of Agriculture, the World Bank and ILRI to compensate farmers who buy insurance cover against the effects of drought.
Ruto pledged a further KShs200 million from the government towards the cover to hasten its expansion to all 14 counties of northern Kenya: Mandera, Wajir, Marsabit, Turkana, West Pokot, Baringo, Laikipia, Isiolo, Samburu,Garissa, Tana River, Lamu, Kajiado and Narok.
The new Kenya Livestock Insurance Program (KLIP) is essentially a scaling-up of an insurance product of ILRI’s, known as the Index-Based Livestock Insurance (IBLI), made possible through ILRI’s partnership with the World Bank Group and the Government of Kenya.
On Monday 20 July 2015, in a meeting organised by the International Livestock Research Institute (ILRI) together with other partners in the livestock sector in Tanzania, President Dr Jakaya Mrisho Kikwete launched the Tanzania’s Livestock Modernization Initiative (TLMI). The Initiative had been prepared during an intensive week-long meeting of livestock experts drawn from Tanzania and abroad.
During the meeting, a strong component of the discussions, also reflected in the TLMI itself, was the issue of rangeland. More than 70% of Tanzania’s approximate 25.8 million cattle and other livestock are bred and managed in Tanzania’s rangeland. However, the Ministry of Lands in Tanzania records that only about 1.28 million hectares or 2.1% of the 60 million hectares of rangelands is protected as grazing in village land use plans. The rest of the grazing areas rely on informal agreements and the weakening capacity of local rangeland users and customary institutions to protect them.
Crop farming is prioritized over livestock despite questions over resulting land use change in both economic and environmental terms. An economic valuation of pastoralism in the Usangu Plain in 2007 showed that if all values were taken into account, the contribution of the livestock subsector to GDP would likely be higher than that of agriculture (See a report by Mdoe and Mnenwa 2007). Yet, conversion of rangelands to irrigated and other crop agriculture in the Usangu Plain continues. Across Tanzania large-scale agricultural schemes, often illegal and haphazard encroachment by farmers, poorly planned infrastructural development contribute to the fragmentation, loss and degradation of rangelands, and the blocking of livestock routes.
Prairie Dog Decline Reduces the Supply of Ecosystem Services and Leads to Desertification of Semiarid Grasslands
Anthropogenic impacts on North American grasslands, a highly endangered ecosystem, have led to declines of prairie dogs, a keystone species, over 98% of their historical range. While impacts of this loss on maintenance of grassland biodiversity have been widely documented, much less is known about the consequences on the supply of ecosystem services.
Here we assessed the effect of prairie dogs in the supply of five ecosystem services by comparing grasslands currently occupied by prairie dogs, grasslands devoid of prairie dogs, and areas that used to be occupied by prairie dogs that are currently dominated by mesquite scrub.
Groundwater recharge, regulation of soil erosion, regulation of soil productive potential, soil carbon storage and forage availability were consistently quantitatively or qualitatively higher in prairie dog grasslands relative to grasslands or mesquite scrub.
Our findings indicate a severe loss of ecosystem services associated to the absence of prairie dogs. These findings suggest that contrary to a much publicize perception, especially in the US, prairie dogs are fundamental in maintaining grasslands and their decline have strong negative impacts in human well – being through the loss of ecosystem services.
Black-Tailed Prairie Dogs, Cattle, and the Conservation of North America’s Arid Grasslands
Prairie dogs (Cynomys spp.) have been eliminated from over 95% of their historic range in large part from direct eradication campaigns to reduce their purported competition withcattle for forage. Despite the longstanding importance of this issue to grassland management and conservation, the ecological interactions between cattle and prairie dogs have not been well examined. We address this issue through two complementary experiments to determine if cattle and prairie dogs form a mutualistic grazing association similar to that between prairie dogs and American bison. Our experimental results show that cattle preferentially graze along prairie dog colony edges and use their colony centers for resting, resembling the mutualistic relationship prairie dogs have with American bison. Our results also show that prairie dog colonies are not only an important component of the grassland mosaic for maintaining biodiversity, but also provide benefits to cattle, thereby challenging the long-standing view of prairie dogs as an undesirable pest species in grasslands.
The edge of an experimental sheep grazing exclusion zone (to the right) within Al Talila Reserve, Palmyra, photographed in March 2008 in the midst of an intense drought period. Sheep quasi uncontrolled grazing was allowed to the left of the fence. Grazing of reintroduced native antelopes at low densities had been allowed within the exclusion zone for a period of 10 years. Photo: Gianluca Serra.
Over-grazing and desertification in the Syrian steppe are the root causes of war
by Gianluca Serra
Civil war in Syria is the result of the desertification of the ecologically fragile Syrian steppe, writes Gianluca Serra – a process that began in 1958 when the former Bedouin commons were opened up to unrestricted grazing. That led to a wider ecological, hydrological and agricultural collapse, and then to a ‘rural intifada’ of farmers and nomads no longer able to support themselves.
A major role in this unfolding disaster was played by affluent urban investors who threw thousands of livestock into the steppe turning the grazing into a large-scale, totally unsustainable, industrial practice.
There is much interest in cultivating C4 perennial plants in northern climates where there is an abundance of land and a potential large market for biofuels. C4 feedstocks can exhibit superior yields to C3 alternatives during the long warm days of summer at high latitude, but their summer success depends on an ability to tolerate deep winter cold, spring frosts, and early growth-season chill.
Here, we review cold tolerance limits in C4perennial grasses. Dozens of C4 species are known from high latitudes to 63 °N and elevations up to 5200 m, demonstrating that C4 plants can adapt to cold climates. Of the three leading C4 grasses being considered for bioenergy production in cold climates—Miscanthus spp., switchgrass (Panicum virgatum), and prairie cordgrass (Spartina pectinata)—all are tolerant of cool temperatures (10–15 °C), but only cordgrass tolerates hard spring frosts. All three species overwinter as dormant rhizomes. In the productive Miscanthus×giganteus hybrids, exposure to temperatures below –3 °C to –7 °C will kill overwintering rhizomes, while for upland switchgrass and cordgrass, rhizomes survive exposure to temperatures above –20 °C to –24 °C. Cordgrass emerges earlier than switchgrass andM. giganteus genotypes, but lacks the Miscanthus growth potential once warmer days of late spring arrive. To enable C4-based bioenergy production in colder climates, breeding priorities should emphasize improved cold tolerance of M.×giganteus, and enhanced productivity of switchgrass and cordgrass. This should be feasible in the near future, because wild populations of each species exhibit a diverse range of cold tolerance and growth capabilities.
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