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The article presents a response to a comment to the article "The Inappropriate Use of Crop Transpiration Coefficients (Kc) to Estimate Evapotranspiration in Arid Ecosystems: A Review." The authors asserted that the objective of the article is to critically examine the Kc method in general perspective. The authors specifically cited that the comments to the article were based on two published papers. And that the common problems in these two papers are overestimating the role of groundwater, assuming that vegetation responds linearly to changes in depth to water, and presuming that higher water tables represent unstressed environments for plants. The concerns of the authors on the oversimplification involved in the Kc method are discussed.

Desert tourism has grown steadily in several regions of the world, due to a post-modern fascination with remoteness, barrenness, silence and solitude. This paper evaluates the trend towards tourism development in South Africa's arid Karoo region. It utilises several methodologies – analysis of discourse, demand and supply – to track the changing profile of tourism in the Great Karoo. The paper concludes that the reputation of the Karoo has shifted profoundly from being hostile, dangerous and boring to being attractive, enticing and spiritual. At the same time, tourists are increasingly expressing favourable opinions of the Karoo as a destination, while accommodation facilities are growing apace. The overview also finds that tourism services in some Karoo towns are developing at a much faster rate than others, so the tourism performance is uneven. A survey of tourists in the Karoo found that the arid environment and small-town ambience offer significant attractions, and Karoo guest houses have a positive outlook for the future. These findings suggest that the Great Karoo is indeed in the process of becoming a tourism destination. [ABSTRACT FROM AUTHOR]

This paper reviews the significant developments in water management that have occurred in Zaragoza, Spain in recent years. Action to achieve more sustainable water management was initiated by a local nongovernmental organisation (Ecodes) persuading and assisting the municipality to improve its delivery performance. Key successes, made by all sectors of the community, include the reduction of water use in the City by 1600 ML/year since 1995 despite significant population growth. The sustainability of the campaign is assessed within a recently devised PESTER framework which systematically addresses the key political, economic, social, technical, environmental and regulatory factors. This highlighted that a workable tariff system has now been achieved which is arguably fair to all, and that a balance has been achieved between local and nationally applicable water law. The main conclusion is that in order to achieve significant progress, it is vital to harmonise the energies, finances and above all commitment of all the main stakeholders. [ABSTRACT FROM AUTHOR]

In the present paper we studied the life history traits related to seed germination of Stipa tenacissima, a key species in semiarid environments of western Mediterranean areas. S. tenacissima is a perennial tussock grass, which has traditionally been considered to expand mainly by vegetative propagation with little or no sexual reproduction. We analysed seed longevity as well as the type of seed dormancy and the role of the seed covers from seeds collected from different populations in SE Spain. We also studied the variation in seed germinability among populations, individuals, and years and the ability of seeds of S. tenacissima to form soil seed banks. There was significant variation in seed germination among individuals, populations and years. Lemma and palea were the main factor controlling these differences since their removal promoted higher and faster germination and eliminated the differences in germination parameters among populations. However, the control of dormancy by lemma and palea was independent of their weight, suggesting that their chemical nature plays a more important role than does size in controlling seed germination. Mechanical scarification treatments (via abrasion with sand) did not affect seed germination. The decay in seed germinability two years after seed collection and the low density of viable seeds in soils one year after seed dispersal indicated that S. tenacissima forms transient soil seed banks. [ABSTRACT FROM AUTHOR]

This long - term rehabilitation experiment is located near Menzel Habib, in the arid zone of southern Tunisia in a site with unambiguously degraded vegetation and soil, caused by a decades - old practice of overexploitation (grazing and plow agriculture). The fundamental premise is that by reintroducing an appropriate combination of native perennial plants, a simplified version of a previously occurring vegetation (and ecosystem) could be reinstated that would utilize the sparse and irregular water resources available in an efficient and complementary fashion, while also showing considerable resistance and resilience to moderate livestock grazing. The long - term goal is, on the basis of such a simplified system, to progressively achieve, through additional reintroductions and other manipulations, a state similar to that of the "ecosystem of reference," an example of which is provided in the nearby Bou Hedma National Park. In this paper we report various aspects of the experiment related to germination and establishment of four supposed keystone species (Rhanterium suaveolens, Plantago albicans, Stipa lagascae, and Cenchrus ciliaris) sown in field conditions, and compared to the ecosystem of reference for a number of parameters related to the structure and functioning of the ecosystems under study. Over a 4 - year period, distinct changes in the desired direction were observed in the experimental plots, and positive effects of controlled grazing were also recorded. [ABSTRACT FROM AUTHOR]

Remote sensingmonitoring of regional ecological quality has advanced significantly with the rapid developments of remote sensing technology. At present, remote sensing ecological index (RSEI) has been widely used in ecological status monitoring. However, RSEI was proposed for urban environments, and the rationality and accuracy of its applicability to desert-dominated arid region ecosystems need to be demonstrated. Therefore, in this study, we incorporated desertification monitoring index (DMI) and salinity monitoring index (SMI) to RSEI and developed the modified remote sensing ecological index (MRSEI) for arid regions. Moreover, we analyzed the stability of MRSEI in ecological status monitoring for arid regions. The MRSEI was then used to evaluate the ecological quality of Inner Mongolia from 2000 to 2020 and exploring its causes. The results show that (1) Although the evaluation results of RSEI and MRSEI are more consistent in areas with high ecological status grades, the MRSEI results are more cautious and reliable in extreme conditions (e.g., desertification, salinization) than the RSEI. (2) Approximately 87.66% of ecological quality have improved or remain stable from 2000 to 2020, but the remaining areas (accounting for 12.34% of the whole area) are still under degraded conditions. This demonstrates that although local governments have made some progress in ecological conservation, the areas that are fluctuating or degraded still require protection or management. (3) In Inner Mongolia, the ecological quality which drove by precipitation (P) & temperature (T) accounting for 26.67% of the study area, population density (D) and GDP per capita (G) affected 13.23% of regional ecological quality. Overall, this research is crucial for evaluating spatial and temporal changes in arid region ecology and establishing conservation strategies. [ABSTRACT FROM AUTHOR]

Urbanization has brought about dramatic changes in the urban environment in China and its associated human population and transportation systems in recent years. However, urbanization in the oases of arid regions of China has been little studied and remains poorly understood. This paper aims to analyze spatiotemporal changes in an urban landscape along major vehicular road transects and compare the relationship between urban growth and transportation in Jiuquan, an oasis city in an arid region of China. We integrated remote sensing images, landscape metrics, and urban-rural gradient analysis to address these questions. The results showed that major vehicular roads stimulated Jiuquan's urban expansion, especially with regard to built-up land containing urban green land areas. Oasis urbanization not only increased landscape fragmentation and structural complexity, but also followed a linear branching, leapfrogging growth pattern characterized by “axial clumps” extending from downtown into rural areas along the road network. The primary source of urban land was not agricultural land, but unused land. These results also indicated that the transect approach implemented along representative roads was effective for studying the urbanization of oasis cities. Such an approach could be applied to master planning in similar oasis cities throughout arid China. [ABSTRACT FROM AUTHOR]

This paper investigates how Borana pastoralists of southern Ethiopia have adapted resource use and livestock mobility practices amid multiple constraints including rising population, loss of rangeland to other pastoral communities and changing access rights, among others. This study uses an innovative multi-scalar methodology to understand how herders' grazing management decisions are made within a context of communal regulations governing access to resources. Grazing itinaries specifying the grazing units used during the past year were established for 91 cattle herds and daily mobility was recorded through 12 months of GPS data monitoring of three herds in three zones within the Borana rangelands. The results revealed communal reorganisation of the grazing areas into units with designated periods of access. Despite the reorganization, herd mobility is severely limited, but to different degrees. In the zones facing most constraints, herd mobility is restricted to the grazing areas within proximity of the respective herder's settlement. However in all the areas, movement outside the herd owners' zone of residence is only practiced as escape mobility, ‘ baqa’ (to flee); instead of the formerly common ‘ godanna’ (to move). These constraints impede fundamental herd mobility needed to meet livestock nutrient requirements, which then affects resilience of the pastoral system. [ABSTRACT FROM AUTHOR]

In semiarid landscapes, the linkage between runoff and vegetation is a particularly close one. In this paper we report on the results of a long-term and multiple-scale study of interactions between runoff, erosion, and vegetation in a piñon-juniper woodland in New Mexico. We use our results to address three knowledge gaps: (1) the temporal scaling relationships between precipitation and runoff; (2) the effects of spatial scale on runoff and erosion, as influenced by vegetation; and (3) the influence of disturbance on these relationships. On the basis of our results, we tested three assumptions that represent current thinking in these areas (as evidenced, for example, by explicit or implicit assumptions embedded in commonly used models). The first assumption, that aggregated precipitation can be used as a surrogate for total runoff in semiarid environments, was not verified by our findings. We found that when runoff is generated mainly by overland flow in these systems, aggregated precipitation amounts alone (by year, season, or individual event) are a poor predictor of runoff amounts. The second assumption, that at the hillslope and smaller scales runoff and erosion are independent of spatial scale, was likewise not verified. We found that the redistribution of water and sediment within the hillslope was substantial and that there was a strong and nonlinear reduction in unit-area runoff and erosion with increasing scale (our scales were slope lengths ranging from I m to 105 m). The third assumption, that disturbance-related increases in runoff and erosion remain constant with time, was partially verified. We found that for low-slope-gradient sites, disturbance led to accelerated runoff and erosion, and these conditions may persist for a decade or longer. On the basis of our findings, we further suggest that (a) disturbance alters the effects of scale on runoff and erosion in a predictable way—scale relationships in degraded areas will be... [ABSTRACT FROM AUTHOR]

The article comments on the research "The Inappropriate Use of Crop Transpiration Coefficients (Kc) to Estimate Evapotranspiration in Arid Ecosystems: A Review." The premise behind the claim of inappropriate use of crop transpiration coefficient is based on a combination of misinterpretation of published results and unfamiliarity with key aspects of hydrologic-vegetation coupling at the scales of interest for water resource management. The coefficients were developed with the full realization they were areal estimates that provide a rationale framework for generalizing results. The authors asserted that it would be difficult to envision successful modeling of phreatophytic systems without recognizing relationships between plant vigor, potential evaporation, soil water, and groundwater.

This article is a Commentary on Larter et al., 215: 97–112. [ABSTRACT FROM AUTHOR]

1 Spatially periodic vegetation patterns are well known in arid and semi-arid regions around the world. 2 Mathematical models have been developed that attribute this phenomenon to a symmetry-breaking instability. Such models are based on the interplay between competitive and facilitative influences that the vegetation exerts on its own dynamics when it is constrained by arid conditions, but evidence for these predictions is still lacking. Moreover, not all models can account for the development of regularly spaced spots of bare ground in the absence of a soil prepattern. 3 We applied Fourier analysis to high-resolution, remotely sensed data taken at either end of a 40-year interval in southern Niger. Statistical comparisons based on this textural characterization gave us broad-scale evidence that the decrease in rainfall over recent decades in the sub-Saharan Sahel has been accompanied by a detectable shift from homogeneous vegetation cover to spotted patterns marked by a spatial frequency of about 20 cycles km−1. 4 Wood cutting and grazing by domestic animals have led to a much more marked transition in unprotected areas than in a protected reserve. 5 Field measurements demonstrated that the dominant spatial frequency was endogenous rather than reflecting the spatial variation of any pre-existing heterogeneity in soil properties. 6 All these results support the use of models that can account for periodic vegetation patterns without invoking substrate heterogeneity or anisotropy, and provide new elements for further developments, refinements and tests. 7 This study underlines the potential of studying vegetation pattern properties for monitoring climatic and human impacts on the extensive fragile areas bordering hot deserts. Explicit consideration of vegetation self-patterning may also improve our understanding of vegetation and climate interactions in arid areas. [ABSTRACT FROM AUTHOR]