Rainwater harvesting for restoring degraded dry agro-pastoral ecosystems: a conceptual review of opportunities and constraints in a changing climate

Water resources in dry environments are becoming scarcer, especially under the changing climate. In response, rainwater harvesting (RWH) is being reemphasized with calls to revive the practice. Ancient knowledge on RWH — mainly the collection through runoff, storage, and use of rainwater for various purposes — is still relevant, especially for dry environments. However, many old practices and technologies may not be suitable or feasible for the present and future. Little has been done to modernize and (or) develop new practices and technologies based on ancient indigenous knowledge. Modernizing old practices or developing new ones and using them in integrated rangelands restoration packages with enabling policy environment can unlock their potential in many water-scarce regions of the world. This paper reviews the state-of-the-art of micro-catchment rainwater harvesting (MIRWH) in dry environments and discusses the opportunities available and the major obstacles faced in using it to restore degraded agro-pastoral ecosystems and support their sustainability. The review highlights the knowledge behind it, the practices developed over the years, and their relevance to today and the future. The paper indicates areas of modernization that can make it more feasible for the future of the dry environments, especially their role in mitigating and adapting to climate change. Conventional and passive approaches to restoring/rehabilitating degraded dry agro-pastoral ecosystems are either too slow to show an obvious impact or not progressing satisfactorily. One main reason is that, because of land degradation, the majority of rain falling on such ecosystems and needed for revegetation is lost with little benefit being gained. Adopting a more progressive intervention to alter the processes of degradation and move towards new system equilibrium is required. MIRWH can enable a large portion of this otherwise lost rainwater to be stored in the soil, and, if used in an integrated packages including suitable plant species and sound grazing management, it may support meaningful vegetation growth and help system restoration. The Badia Benchmark project, implemented by ICARDA in Jordan and Syria, has demonstrated the potential for adoption at large scale in similar environments. This case study illustrates the potential and the constraints of this practice.

Molecular systematics of the South American rodent Calomys laucha (Cricetidae: Sigmodontinae), a reservoir of the Laguna Negra hantavirus

The small vesper mouse (Calomys laucha (Fischer, 1814)) (Cricetidae: Sigmodontinae) ranges widely in Brazil, Uruguay, Paraguay, Argentina, and Bolivia. The species is the reservoir of the Laguna Negra hantavirus (LNV) in Paraguay but not in Argentina, where it is one of the most abundant rodents in agro-pastoral ecosystems. To answer the question if the nominal species C. laucha constitutes a single genetic unit or if it presents genetic discontinuities that may relate to hosting LNV, we sequenced the cytochrome b (cyt b) gene of specimens from throughout the range of the distribution of the species. Phylogenetic analyses revealed two well-supported clades. Twenty-two sequences from Argentina, Paraguay, and Bolivia grouped in clade A, but three sequences from Uruguay and Brazil clustered in a quite divergent clade B. The genetic distance between the two groups is 5.75%. No significant differences between Argentinean, Paraguayan, and Bolivian specimens assigned to C. laucha were detected. The restricted distribution of LNV associated to C. laucha in central Paraguay could be explained by a “natural nidality” phenomenon.

Consequences of nutrition during gestation, and the challenge to better understand and enhance livestock productivity and efficiency in pastoral ecosystems

The major economic costs to ruminant livestock producers of meat are associated with the breeding herd, which is an important target for improving productivity and efficiency at pasture. There is increasing interest in how to manage breeding females and their offspring to either minimise the consequences of adverse environmental effects or to enhance productivity and efficiency of offspring. This paper briefly reviews influences on fetal growth including the placenta, and reports results of our studies on factors including chronic, severe nutritional restriction during pregnancy and/or lactation within pasture-based systems on postnatal productivity of beef cattle. Cattle severely growth restricted early in life can have reduced weight for age to market weight, but with little or no alteration to normal allometric growth patterns of carcass tissues or beef quality, at least within pasture-based systems. The extent to which Bill McClymont’s vision of improving productivity and efficiency through improved understanding of the interactions between livestock, plants and soils can be realised is limited by our capacity to generate, in a timely manner, objective data on animal performance including intake and feed use efficiency within pastoral ecosystems. The capacity to improve productivity and efficiency, most notably for the breeding herd, within pastoral ecosystems will be enhanced by the development of wireless sensor networks and methods to manage and develop applications from ‘big data’. These applications of wireless sensor networks will include measurement of pasture intake, which is the input trait that underpins livestock production efficiency. Consistent with Bill McClymont’s vision, consumption of pasture by ruminants represents the point in the grazing ecosystem where livestock interface with plants and soils, and thus measurement of pasture intake should be a high priority for future research on productivity and efficiency.