Pyrenean Pastoralists’ Ecological Knowledge: Documentation and Application to Natural Resource Management and Adaptation

Pastoral production systems in the Spanish Pyrenees have changed dramatically in recent decades, leading to the loss of traditional ecological knowledge (TEK). We documented TEK of pastoralists from two valleys in the western Central Pyrenees of Aragón and explored its potential applications to resource management and adaptation. Pyrenean pastoralists possess extensive knowledge of relationships between terrain, climate, vegetation and animal nutrition and behavior. TEK could contribute to sustainable stewardship and facilitate adaptation by informing pasture monitoring; providing traditional practices to manage mountain vegetation; and preserving knowledge of extensive livestock production strategies, such as transhumance. Institutional barriers to applying TEK include weak economic cooperation among stockmen, their dependence on EU subsidies, and lack of voice in regional government decisions about local resources. A more collaborative, place-based stewardship of the Central Pyrenees might begin with direct involvement of pastoralists in designing monitoring of pasture conditions and vegetation type changes.     

Pastoralist Decision-Making on the Tibetan Plateau

Despite a growing body of research about rangeland degradation and the effects of policies implemented to address it on the Tibetan Plateau, little in-depth research has been conducted on how pastoralists make decisions. Based on qualitative research in Gouli Township, Qinghai province, China, we analyze the context in which Tibetan herders make decisions, and their decisions about livestock and pastures. We refute three fundamental assumptions upon which current policy is premised: that pastoralists aim to increase livestock numbers without limit; that, blindly following tradition, they do not actively manage livestock and rangelands; and that they lack environmental knowledge. We demonstrate that pastoralists carefully assess limits to livestock holdings based on land and labor availability; that they increasingly manage their livestock and rangelands through contracting; and that herding knowledge is a form of embodied practical skill. We further discuss points of convergence and contradiction between herders’ observations and results of a vegetation analysis.     

Livestock Transfers, Risk Management, and Human Careers in a West African Pastoral System

Pastoralists employ different strategies to minimize the risk of losing their livelihood due to drought, disease, and other disasters. Livestock transfers have been considered critical because they provide not only a safety net during disasters but also contribute to the resilience of pastoral societies by allowing pastoralists to rebuild their herds after disasters. I examine whether and how livestock transfers serve as risk management strategies in a comparative, ethnographic study of three pastoralist communities in the Far North Region of Cameroon. The findings show that livestock transfers contribute to short-term survival of households but not long-term viability of family herds. Here I argue for a more holistic, anthropological approach that considers the social and cultural aspects of strategic decisions that individual pastoralists make when they engage in these transfers.     

Herd composition in an Aymara community of the Peruvian Altiplano: A linear programming problem

A model of herd management is presented for Aymara alpaca herders in the south central Andes. Linear programming methods and subjective utility values are used to model how pastoralists choose the size of their herd and the species they raise. These decisions are modeled in light of the land and labor resources available to pastoralists, and the products Andean herders must derive from their herds (meat, wool, and dung). The model predicts typical herd size in the community of Chinchillape, and has implications for social and economic changes seen in the Andes today. Specifically, pastoralists in Chinchillape are pursuing maximizing strategies, optimizing herd value by concentrating on alpacas, and decreasing the proportion of llamas in their herd in response to expanding transportation systems. Finally, results of the models indicate that sheep are a very poor option for Andean herders. This explains the reluctance of indigenous herders to adopt sheep herding in some areas of the Andes.     

川西北草原土壤及冷暖季牧草微量元素含量比较

改善土壤的理化环境及提高牧草的营养水平必须了解草地土壤及牧草微量元素的分布与含量。试验从川西北草地的亚高山丘原草甸、亚高山平坝草甸和沼泽平坝草甸采集土样和冷暖季草样。土样采集深度范围是0～10cm,10～20cm,20～30cm。应用火焰原子吸收光谱法测定了草样中铜、铁、锰、锌和钴的含量和土样中这些元素的有效态含量,应用氟离子选择电极法测定了土样中的氟离子浓度和草样中的氟含量。土壤pH高低顺序为草甸土>冲积土>泥炭草甸土,pH随土壤深度变深而下降;土壤和牧草的钴含量都处于缺乏状态,分别为0.64mg/kg和0.26mg/kg。牧草铁和锰含量都高于正常水平,铁为414.51～565.06mg/kg,锰为138.68～247.09mg/kg.     

Comparative Metabolite Fingerprinting of the Rumen System during Colonisation of Three Forage Grass (Lolium perenne L.) Varieties

The rumen microbiota enable ruminants to degrade complex ligno-cellulosic compounds to produce high quality protein for human consumption. However, enteric fermentation by domestic ruminants generates negative by-products: greenhouse gases (methane) and environmental nitrogen pollution. The current lack of cultured isolates representative of the totality of rumen microbial species creates an information gap about the in vivo function of the rumen microbiota and limits our ability to apply predictive biology for improvement of feed for ruminants. In this work we took a whole ecosystem approach to understanding how the metabolism of the microbial population responds to introduction of its substrate. Fourier Transform Infra Red (FTIR) spectroscopy-based metabolite fingerprinting was used to discriminate differences in the plant-microbial interactome of the rumen when using three forage grass varieties (Lolium perenne L. cv AberDart, AberMagic and Premium) as substrates for microbial colonisation and fermentation. Specific examination of spectral regions associated with fatty acids, amides, sugars and alkanes indicated that although the three forages were apparently similar by traditional nutritional analysis, patterns of metabolite flux within the plant-microbial interactome were distinct and plant genotype dependent. Thus, the utilisation pattern of forage nutrients by the rumen microbiota can be influenced by subtleties determined by forage genotypes. These data suggest that our interactomic approach represents an important means to improve forages and ultimately the livestock environment.     

Cattle and pastoralism: Survival and production in arid lands

Traditional subsistence pastoralists in East Africa tend to keep large herds, milk cattle in preference to eating them, and subject them to long foraging treks. Such practices are widely considered ill-suited to arid lands and are believed to arise because cattle are raised more for social prestige than food production. Whether this is true can only be judged by considering the responses of cattle to arid zones and, given the herder's goals and options, his management practices. In considering these factors, we show that indigenous East African cattle demonstrate energy-sparing capabilities during drought. Pastoralists can therefore herd cattle at great distances from water at little more cost than animals on the normal maintenance diet and watered more frequently. The physiological response of cattle to drought, the ecological constraints imposed by livestock and wildlife competition, and the energetic efficiency of mixed milk and meat pastoralism explain why herders traditionally select their characteristic management practices.     

Knowledge of Bovine Tuberculosis,Cattle Husbandry and Dairy Practices amongst Pastoralists and Small-Scale Dairy Farmers in Cameroon

Background

Control of bovine tuberculosis (bTB) and zoonotic tuberculosis (zTB) has relied upon surveillance and slaughter of infected cattle, milk pasteurisation and public health education. In Cameroon, like many other sub-Saharan African countries, there is limited understanding of current cattle husbandry or milk processing practices or livestock keepers awareness of bTB. This paper describes husbandry and milk processing practices within different Cameroonian cattle keeping communities and bTB awareness in comparison to other infectious diseases.

Study design

A population based cross-sectional sample of herdsmen and a questionnaire were used to gather data from pastoralists and dairy farmers in the North West Region and Vina Division of Cameroon.

Results

Pastoralists were predominately male Fulanis who had kept cattle for over a decade. Dairy farmers were non-Fulani and nearly half were female. Pastoralists went on transhumance with their cattle and came into contact with other herds and potential wildlife reservoirs of bTB. Dairy farmers housed their cattle and had little contact with other herds or wildlife. Pastoralists were aware of bTB and other infectious diseases such as foot-and-mouth disease and fasciolosis. These pastoralists were also able to identify clinical signs of these diseases. A similar proportion of dairy farmers were aware of bTB but fewer were aware of foot-and-mouth and fasciolosis. In general, dairy farmers were unable to identify any clinical signs for any of these diseases. Importantly most pastoralists and dairy farmers were unaware that bTB could be transmitted to people by consuming milk.

Conclusions

Current cattle husbandry practices make the control of bTB in cattle challenging especially in mobile pastoralist herds. Routine test and slaughter control in dairy herds would be tractable but would have profound impact on dairy farmer livelihoods. Prevention of transmission in milk offers the best approach for human risk mitigation in Cameroon but requires strategies that improved risk awareness amongst producers and consumers.     

Changing Access to Labor,Pastures, and Knowledge: The Extensification of Grazing Management in Sudano-Sahelian West Africa

The broader ecological and social contexts within which livestock husbandry of Sudano-Sahelian West Africa operates have changed significantly over the past thirty years. This study concerns how: (1) these broader trends have affected the quantity and quality of labor investments into livestock herding; and (2) the ecological and animal nutritional implications of observed variation in labor investments into herding. The study was conducted in a 500 km² area of western Niger using a combination of qualitative interviews of herders and herd managers, household composition surveys, herd composition monitoring, grazing management monitoring and georeferenced vegetation and livestock grazing itinerary data. Statistical analyses were performed using a two-staged approach: (1) analysis of the factors affecting the allocation of labor to herding at the level of the managing household; and (2) analysis of the effect of herd characteristics, season, microgeography and herders’ social position on herders’ effort and the nutritional and ecological impacts of these efforts. The results of these analyses support the conclusion that the changing regional context of livestock husbandry leads to a reduction in labor (quantity and quality) investment or an “extensification” of herding with significant implications for livestock productivity and the environment.

The Distribution of Grazing Pressure in Relation to Vegetation Resources in Semi-arid West Africa: The Role of Herding

In semi-arid West Africa, livestock are increasingly managed by sedentary producers in close proximity to expanding cropped lands. To evaluate the agricultural and environmental implications of this trend, a study was conducted to investigate the effect of grazing management on the spatial distribution of grazing pressure, the forage provided animals during the grazing period, and local herd-forage ratios across three agropastoral landscapes characterized by varying cultivation pressure. During the 19-month study period, data on herbaceous vegetation, livestock populations, and grazing itineraries were collected. These data were referenced to land units averaging 70 ha in area. Using this approach, each of 3,819 grazing itineraries was characterized as to: 1. the sum of the products of the palatable forage mass of a particular land unit and the time spent grazing by the herd within that unit (FAT, expressed in kg-hours ha⁻¹); and 2. the average palatable herbaceous forage mass encountered by livestock across the itinerary weighted by the time spent in the land units crossed (FA, expressed in kg ha⁻¹). The spatial dispersion of livestock grazing around human settlements was found to decline with a reduction in herding labor investment (herded>herd-release>free pasture). Multiple regression analyses of itinerary data demonstrate that both FAT and FA also decline with a reduction in herding labor investment. Herded and herd-release managed livestock were offered more palatable forage and grazed areas of higher forage availability than free-pastured animals. This supports arguments that as the investment of time and effort into herding declines, feed supply to livestock will decline and the potential for grazing-induced environmental change will increase.     

Condensed Tannins' Effect on White-Tailed Deer Forage Digestibility in Mississippi

Abstract: Condensed tannins (CT) can reduce digestibility of forages for white-tailed deer (Odocoileus virginianus), potentially confounding estimates of diet quality and nutritional carrying capacity. We collected 143 spring and 142 summer samples of 8 important deer forage species from 22 properties in Mississippi, USA, and tested for CT content using a modified butanol-HCl assay. Three species (partridge pea [Chamaecrista fasciculata], southern dewberry [Rubus trivialis], and roundleaf greenbrier [Smilax rotundifolia]) contained CT, ranging from 0.11% to 6.46% dry weight. Summer CT concentration was greater than in spring for 2 species. We ranked soil samples from least to most fertile using 8 chemical characteristics and found a positive correlation between fertility and CT concentration for 1 species and no correlation for 2 species. We tested effects of CT concentration on in vitro dry matter disappearance (IVDMD) and in vitro protein digestibility using samples of partridge pea and roundleaf greenbrier and rumen fluid from 3 free-ranging deer. Average IVDMD was reduced 1.9% for each 1% increase in CT concentration. In vitro protein digestibility was reduced 2.5% for each 1% increase in CT concentration. Assuming that our methods reflect the effects of CT on in vivo digestibility, maximum loss of available crude protein (CP) in our samples was 3.0 g/100 g dry-weight forage, and only 13 of the 112 CT-containing forage samples (12%) would have decreased available CP by >1 g/100 g dry-weight forage. Deer consuming equal portions of sampled forages would lose <1% of dietary CP to CT. Comparisons of foraging area quality using crude protein estimates should be unaffected by CT under reasonable restrictions of similar habitat types, soil fertility, and time. Given the ability of deer to forage selectively and the abundance of alternative forages in Mississippi, the potential for CT to substantially affect spring or summer diet quality of deer appears minimal.     

Landscape nutritional patterns and cattle distribution in rangeland pastures

On rangelands, uneven or unmanaged livestock distribution can adversely affect plant community composition, riparian function, or displace wildlife. These issues have historic precedents and are still a challenge for those managing rangelands. A thorough understanding of the mechanisms governing livestock distribution can help land and livestock managers avoid or ameliorate many deleterious effects. To that end, this research tested hypotheses that grazing cattle seek nutritionally superior portions of rangeland pastures. Global positioning system (GPS) collars were used to track cattle movement and activity in three, 800+ ha pastures where the spatial distribution of standing crop, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and forage digestibility (in situ dry matter disappearance (ISDMD)) were mapped in late spring. Four of five analyses implied grazing cattle spatially responded to forage quantity/quality attributes. Analyses indicated cattle favored higher than average CP (P = 0.006) and ISDMD (P = 0.078), and lower than average NDF (P = 0.003) and standing crop (P = 0.069) locales. No significant effect (P = 0.954) occurred with ADF analyses. Correlations among those variables imply cattle may simultaneously respond to more than one nutritional attribute as they select foraging locales. Stepwise regression, however, relating grazing distribution to geophysical and forage quantity/quality characteristics were extremely poor predictors of where cattle grazed. Listed in order of entry, the model implied elevation above or below stock water, horizontal distance to stock water, forage CP content, and degree of slope were the site specific attributes most associated with cattle distribution. We speculate that cattle interactions with landscape level nutritional dynamics may at least partially explain seasonal changes in distribution and forage use by cattle across the landscape. These findings should help land and livestock managers understand, explain, and manipulate livestock distribution on their holdings.     

Knowledge of Mange among Masai Pastoralists in Kenya

Background

Pastoralists in low-income countries usually live in close proximity to their animals and thus represent an important repository of information about livestock disease. Since wild and domestic animals often mix freely whilst grazing, pastoralists are also able to observe first-hand the diseases that are present in wildlife and as such are key informants in disease outbreaks in sylvatic animals. We report here the findings of the first study of the knowledge and role of Masai pastoralists in mange in wildlife and livestock in Masai Mara, Kenya.

Methodology/Principal Findings

In this paper we describe the knowledge of mange accrued by 56 Masai pastoralists in Kenya and how they respond to it in both wildlife and livestock. In total, 52 (93%) pastoralists had a clear idea of the clinical appearance of mange, 13 (23%) understood its aetiology and 37 (66%) knew that mites were the causal agent. Thirty-nine (69%) believed that mange cross-infection between domestic and wild animals occurs, while 48 (85%) had observed mange in domestic animals including sheep (77%), goats (57%), dogs (24%) and cattle (14%). The pastoralists had also observed wild animals infected with mange, above all lions (19%), gazelles (14%), cheetahs (12%) and wildebeests (2%). In 68% of cases Masai pastoralists treat mange infection or apply control measures, most commonly via the topical use of acaricides (29%) and/or the reporting of the outbreak to the veterinary authorities (21%). In the period 2007–2011, Kenya Wildlife Service received 24 warnings of 59 wild animals with mange-like lesions from the Masai Mara pastoralist community. The reported species were cheetah, lion, wild dog, Thomson’s gazelle and wildebeest.

Conclusion

Masai pastoralists have good knowledge of mange epidemiology and treatment. Their observations and the treatments they apply are valuable in the control of this disease in both wild and domestic animals.     

The effect of livestock production system and concentrate level on carcass traits and meat quality of foals slaughtered at 18 months of age

This trial was conducted to study the effect of livestock production system (freedom extensive system (FES) v. semi extensive system (SES)) and amount of finishing feed (1.5 v. 3.0 kg of commercial feed) in SES on carcass characteristics, meat quality and nutritional value of meat foal slaughtered at 18 months of age. For this study, a total of 49 foals (21 from FES and 28 from SES) were used. The obtained results showed that SES had a positive influence on carcass characteristic because these foals showed the best values for live weight, carcass weight, dressing percentage, perimeter of leg (PL) and carcass compactness index. On the other hand, finishing feeding also had a significant (P<0.05) effect on PL and lean thickness, as the highest values were obtained in foals finished with 3 kg of commercial fodder. The physico-chemical properties were significantly affected by the livestock production system with the exception of ashes content (P>0.05). Foals finished in SES increased in 408% the intramuscular fat content (0.23 v. 1.17%, for foals reared in FES and SES, respectively). On the other hand, L*-value and a*-value were significantly (P<0.01) affected by livestock production system, as foals from the FES group had a more intense redder color (higher CIE a*-value) and higher lightness (higher CIE L*-value) compared with those from the SES group. Finally, meat nutritional value was significantly affected by livestock production system, as foals from an extensive production system on wood pasture could be considered as healthier in relation to their fatty acid profiles (low n-6/n-3 ratio and high hypocholesterolemic/hypercholesterolemic ratio) as a result of the beneficial grass intake on meat fatty acid profile.     

Sows’ preferences for different forage mixtures offered as fresh or dry forage in relation to botanical and chemical composition

Providing forage to feed-restricted pregnant sows may improve their welfare by reducing their high feeding motivation. The aim of this study was to determine sows’ preferences for four forage mixtures cultivated in Canada. Forage mixtures were compared when offered either fresh or dry. The four forage mixtures were composed of different proportions and species of legumes (alfalfa (Alf) or red clover (Clo)) and grasses (tall fescue (F) and/or timothy (T)): (1) Alf-F, (2) Alf-F-T, (3) Clo-T and (4) Clo-F-T. Voluntary intake was measured, and preference tests were carried out for two experiments: one in spring for fresh forages ( n = 8) and the other in autumn for hays ( n = 8) with different sows housed in individual pens and fed a concentrated diet meeting their nutritional requirements for maintenance and foetal growth. Voluntary intake was measured by offering each forage mixture separately (one forage mixture/day) during 90 min according to a 4 × 4 Latin square design replicated four times. During preference tests, all six combinations of two forage mixtures were offered once (one combination/day) for 45 min to each sow. Individual forage intake was measured, and feeding behaviour was observed. Forages were analysed for botanical and chemical composition. Difference in voluntary intake among the four forage mixtures was determined using a variance analysis followed by Tukey tests for post hoc comparisons. In preference tests, differences between the two forage mixtures offered were determined using a paired Student’s t test, and the most ingested forage mixture was considered the preferred one. Results from both experiments revealed clear preferences for some forage mixtures when offered either fresh or dry. Forage mixtures with a greater proportion of legumes (AlfT and CloT) were preferred over forage mixtures with a higher proportion of grasses (AlfFT and CloFT). The AlfFT and CloFT forage mixtures contained at least 30% of fescue; therefore, the greater preference for the AlfT and CloT forage mixtures could also be due to the absence of fescue. Sows preferred forages with low DM and NDF concentrations and high CP and non-structural carbohydrates concentrations. Based on results from previous studies, the preferences seen in the present study are most likely due to the greater proportion of legumes, although an effect of tall fescue in preference cannot be excluded. Therefore, offering forages with a high proportion of legumes would be a good strategy to maximise both fresh and dry forage intake in pregnant sows.     

Comparison of muscle fatty acid composition and lipid stability in lambs stall-fed or pasture-fed alfalfa with or without sainfoin pellet supplementation

Currently, consumers are increasingly interested in obtaining high-quality and healthy lamb meat. Compared to grain-based diets, dietary forage legumes such as alfalfa and condensed tannin (CT)-rich sainfoin increase the levels of polyunsaturated fatty acids (PUFAs) that are beneficial for health in lamb meat thanks to their high content in PUFA and/or their impact on ruminal biohydrogenation. However, they can therefore adversely affect its oxidative stability. Thus, the impact of dietary forage legumes on lamb longissimus thoracis (LT) muscle FA composition and their stability to peroxidation was studied in 36 Romane lambs grazing alfalfa (AF; n = 12) or alfalfa plus daily supplementation with CT-rich sainfoin pellets (AS; n = 12; 15 g DM/kg BW, 42 g CT/kg DM) or stall-fed concentrate and grass hay indoors (SI; n = 12). Lambs were slaughtered at a mean age of 162 ± 8.0 days after an average experimental period of 101 ± 8.1 days. Forage legumes-grazing lambs outperformed SI lambs in LT nutritional quality, with more conjugated linoleic acids and n-3 PUFAs, especially 18:3n-3, eicosapentaenoic and docosahexaenoic acids (P < 0.001), and thus lower n-6 PUFA/n-3 PUFA and 18:2 n-6/18:3 n-3 ratios (P < 0.001). Peroxidizability index was higher (P < 0.001) in LT muscle of forage legumes-grazing lambs. Concurrently, two endogenous antioxidant enzyme activities, superoxide dismutase and glutathione peroxidase, were, respectively, similar and lower (P < 0.001) for forage legumes-grazing compared with SI lambs. A lower vitamin E level in SI lambs compared with forage legumes-grazing lambs (1.0 v. 3.8 mg/g, P < 0.001) could explain that malondialdehyde content, a marker of lipid oxidation intensity, was 0.63 µg/g in SI after 8 days in aerobic packaging conditions, whereas it remaining steady at 0.16 µg/g in forage legumes-grazing lambs. Dietary forage alfalfa thus improved FA composition of lamb LT muscle and their stability to oxidation when compared to SI lambs. However, supplementation of alfalfa-grazing lambs with CT-rich sainfoin pellets did not affect the nutritional quality of LT muscle FAs.     

Degraded soil increases the performance of a dominant grass, <Emphasis Type="Italic">Andropogon gerardii</Emphasis> (Big bluestem)

Dominant grasses can suppress subordinate species in grassland restorations. Examining factors that influence performance of a dominant grass when interacting with subordinate forbs may provide insights for maintaining plant community diversity. The objective of our study was to determine how soils of different restoration ages and functionally different forbs influence the performance (using biomass and tillering rate as proxies) of a dominant grass: Andropogon gerardii. Sites included a cultivated field and two restored prairies (4 or 16 years after restoration) at Konza Prairie (NE Kansas). We hypothesized A. gerardii performance would be greater in more degraded soils and when interacting with legumes. Soil structure, nutrient status, and microbial biomass were measured in soil that was used to conduct the plant interaction study. Andropogon gerardii performance was measured during an 18-week greenhouse experiment using the relative yield index calculated from net absolute tillering rate and final biomass measurements in three soil restoration age treatments combined with four interacting forb treatments. Restoration improved soil structure, reduced plant-available nutrients, and increased microbial biomass. Relative yield index values of A. gerardii were greater with non-legumes than legumes. Andropogon gerardii performed best in degraded soils, which may explain the difficulty in restoring tallgrass prairie diversity in long-term cultivated soil. Results from this study suggest practices that promote soil aggregation and fungal biomass, coupled with including a high abundance of legumes in seed mixes could reduce dominance of A. gerardii and likely increase plant diversity in tallgrass prairie restorations.     

Bioconcentration of some macrominerals in soil,forage and buffalo hair continuum: A case study on pasture irrigated with sewage water

The present study aimed to evaluate the bioaccumulation of some macrominerals in grazing buffaloes fed forage irrigated with sewage water or canal water. In particular, the transfer of sodium (Na), magnesium (Mg), potassium (K) and calcium (Ca) from soil to plant and in turn to animals was evaluated under sub-tropical environmental conditions. Samples of soil, forage and buffalo hair were collected and digested by wet method. Sodium and K concentrations were significantly higher in the soil but lower in the forages; however, Mg and Ca concentrations in both soil and forages were higher. The correlation between soil, forage and hair showed an imbalanced flow of Na, Mg and K and a balanced flow of Ca from soil to forage and then to animals. Based on the findings, the highest rates of transfer of minerals were found for sewage water treatment, whereas lowest rates were found for canal water treatment, except for Na. As the transfer of minerals depends on their bioavailability, the highest values may be due to the high rates of mineral uptake by plants. Thus, the high transfer rate of some elements by plants could become toxic in future causing detrimental effect to grazing livestock.     

How pastoralism changes savanna vegetation: impact of old pastoral settlements on plant diversity and abundance in south-western Kenya

For centuries, pastoralists have influenced savanna ecology through their construction of settlements, traditional movement patterns in search of forage, water and safety for their livestock. Construction of settlements initiates localised changes in the vegetation due to clearance of vegetation at construction and collection of construction materials. During the occupation period a lot of dung is deposited in and around settlements. When pastoral families abandon settlements and move away, they leave behind mud huts and livestock corrals surrounded by fences. These sites become nutrient-rich patches supporting a different abundance and diversity of plants and large mammals compared to the rest of the savanna. This study aimed to broaden our understanding of how pastoral land use influences plant diversity in East African savannas. Past work on the effects of settlements has been done in dry places (<600 mm rainfall) with relatively poor soils. To complement and extend these studies, we selected a contrasting site with high rainfall and rich soils in the Mara ecosystem of south-western Kenya. We sampled the occurrence of different plant species along transects radiating from 28 settlements abandoned by pastoralists and ranging in age from 2 months to 48 years on two different soil types. Mean plant species richness and abundance peaked at intermediate distances, 12.5 and 25 m from the edges of settlements. We recorded a total of 210 plant species during the study, 65 of which occurred only within the impact ring of the abandoned settlements. The effects of settlements on plants were stronger on shallow sandy soils than on deep clay soils. Our findings show that abandoned settlements were key sites for regeneration and replenishment of shrubs harvested by the Maasai, but support few other plants of biodiversity value. These unique habitat patches in the savanna ecosystem are under threat as pastoral Maasai become increasingly sedentary and as wildlife conservancies are established, thus reducing the number of abandoned settlements. In essence, the Maasai, by changing their traditional lifestyle, will reduce these nutrient hotspots and hence landscape heterogeneity and biodiversity.     

山地-绿洲“共轭型”生态牧场理念源起、概念框架与发展模式——以祁连山牧区为例

区域协调发展空间布局及耦合效应是国土空间治理现代化、区域生态保护和高质量发展绕不开的重要命题。本研究利用146户牧户访谈和21次管理部门调研资料,结合卫星遥感数据和文献资料,从“三生”(生产、生活、生态)视角爬梳祁连山草地畜牧业、河西走廊饲草种植业、牧户生计路径策略的历史源起和发展历程。在生态系统服务流理论指导下深入刻画了祁连山与河西走廊农牧耦合系统的空间联系,诠释了祁连山-河西走廊“共轭型”生态牧场概念框架与发展模式。研究认为：(1)2011年“草原生态奖补政策”实施以来祁连山地区植被覆盖度增加显著(P<0.05);传统牧业户、生态移民户的生计多样化指数分别是2.22和2.69,生计能力脆弱;外购草料、舍饲养殖、人工种草、异地借牧(秸秆补饲)、流转草原等是牧户落实草畜动态平衡的基础性生计策略,实现了祁连山草地畜牧业由超载过牧到“超载不过牧”的跨越式转型;(2)祁连山山地系统将生态系统服务(淡水资源供给)外溢至河西走廊绿洲系统以支撑饲草种植业发展,河西走廊饲草种植业提供优质饲草“反哺”祁连山草地畜牧业发展,二者构成了山地-绿洲“共轭空间”;借助外界物质能量输入路径的“虚拟草场”模...