Climate as a determinant of dung beetle response to native forest replacement by cattle pastures in South America

Anthropogenic disturbance in natural ecosystems reduces the number of species in biological communities and homogenizes their composition across different regions. Climate is one of the main abiotic determinants of species distributions and different factors were proposed as the main climatic drivers. Here we explored the role of regional climate on the local response of dung beetle assemblages to the replacement of native forest by cattle pastures in South America by simultaneously contrasting three climatic hypotheses: energy, seasonality and heterogeneity. We compiled a database by searching published studies comparing dung beetle richness and composition between both native forests and cattle pastures. We calculated the proportional difference in species richness and composition between habitat types. As explanatory variables, we used seven abiotic variables grouped into the three climatic hypotheses. Energy/Productivity: mean annual temperature (°C/year) and total annual precipitation (mm/year). Seasonality: annual thermal amplitude (°C/year), the average coefficient of variation of monthly precipitation and the coefficient of average monthly variation in temperature. Heterogeneity: coefficient of variation of mean annual temperature, coefficient of variation of mean annual precipitation. Using regression analyses and a model selection procedure, we found differences in species richness between native forests and cattle pastures were explained by the coefficient of variation of mean annual precipitation, whereas changes in species composition were explained by total annual precipitation and the coefficient of variation of mean annual precipitation. The response of dung beetle assemblages to livestock grazing in South American forests was associated with precipitation variation. The heterogeneity hypothesis better explained changes in species richness following forest replacement by cattle pastures, while both energy/productivity and heterogeneity hypotheses explained the changes in species composition.     

家畜吸血蝇的初步调查

1981年在福建省三明福建农学院牧场和河南省汝南县牛,马体上调查采集得吸血蝇5种。两地均以厩螯蝇为优势种,分别占93.4%和81.6%,气温16.5-31℃条件下,南螯蝇卵期2天,幼虫期19天,蛹期11天,螯蝇成蝇一天中以下午活动最频繁。一只厩螯蝇平均每次可吸血19.3mg。吸饱血后体重增加2.322倍。在河南省汝南县兽医院临床所见,吸血蝇对家畜危害病例有贫血,骚扰、过敏性皮炎等。应用敌敌畏杀灭吸血蝇成蝇效果好,但因毒性高,在畜舍内使用易发生中毒事故。     

Below‐ground biomass and productivity of a grazed site and a neighbouring ungrazed exclosure in a grassland in central Argentina

Abstract We estimated the below‐ground net plant productivity (BNPP) of different biomass components in an intensively and continuously 45‐ha grazed site and in a neighbouring exclosure ungrazed for 16 years for a natural mountain grassland in central Argentina. We measured approximately twice as much dead below‐ground biomass in the grazed site as in the ungrazed site, with a strong concentration of total below‐ground biomass towards the upper 10 cm of the soil layer in both sites. The main contribution to total live biomass was accounted for by very fine (<0.5 mm) and fine roots (0.5–1.0 mm) both at the grazed (79%) and at the ungrazed (81%) sites. We measured more dead biomass for almost all root components, more live biomass of rhizomes, tap roots and bulbs, and less live biomass of thicker roots (>1 mm) in the grazed site. The seasonal variation of total live below‐ground biomass mainly reflected climate, with the growing season being limited to the warmer and wetter portion of the year, but such variation was higher in the grazed site. Using different methods of estimation of BNPP, we estimated maximum values of 1241 and 723 g m^?2 year^?1 for the grazed and ungrazed sites, respectively. We estimated that very fine root productivity was almost twice as high at the grazed site as at the ungrazed one, despite the fact that both sites had similar total live biomass, and root turnover rate was twofold at the grazed site.     

Qualification and assessment of work organisation in livestock farms

Farmers have to cope with both society and market pressures in their working practices, as well as with the enlargement of farms, off-farm opportunities and profound changes in the workforce. Expectations in terms of working duration and rhythms are increasingly expressed by farmers, meaning that working conditions and the efficiency of work organisation are critical issues nowadays. The bibliography shows that work organisation is mainly discussed by social scientists, but that livestock scientists make a significant contribution to the debate. Indeed, technical changes modify working calendars, priorities between tasks and interchangeability among workers; technical adaptations are levers to solving problems of work with equipment, buildings and the workforce. We present here French approaches to work organisation that take into account livestock management and its implications in work organisation. The 'Work Assessment' method represents the work organisation and evaluates work durations and time flexibility for farmers. The ATELAGE model describes and qualifies work organisation with its various regulations and time scales, integrating the other activities - economic or private - that farmers can carry on. Three principles underpin them: not all workers are interchangeable; tasks have different temporal characteristics (rhythms, postponement, etc.); and the year is a succession of work periods that differ in their daily form of organisation. We illustrate with concrete examples how these approaches contribute to helping and guiding farmers in their thoughts about change.     

Expansion of human settlement in Kenya's Maasai Mara: what future for pastoralism and wildlife?

Aim Wildlife and pastoral peoples have lived side‐by‐side in the Mara ecosystem of south‐western Kenya for at least 2000 years. Recent changes in human population and landuse are jeopardizing this co‐existence. The aim of the study is to determine the viability of pastoralism and wildlife conservation in Maasai ranches around the Maasai Mara National Reserve (MMNR). Location A study area of 2250 km² was selected in the northern part of the Serengeti‐Mara ecosystem, encompassing group ranches adjoining the MMNR. Emphasis is placed on Koyake Group Ranch, a rangeland area owned by Maasai pastoralists, and one of Kenya's major wildlife tourism areas. Methods Maasai settlement patterns, vegetation, livestock numbers and wildlife numbers were analysed over a 50‐year period. Settlement distributions and vegetation changes were determined from aerial photography and aerial surveys of 1950, 1961, 1967, 1974, 1983 and 1999. Livestock and wildlife numbers were determined from re‐analysis of systematic reconnaissance flights conducted by the Kenya Government from 1977 to 2000, and from ground counts in 2002. Corroborating data on livestock numbers were obtained from aerial photography of Maasai settlements in 2001. Trends in livestock were related to rainfall, and to vegetation production as indicated by the seasonal Normalized Difference Vegetation Index. With these data sets, per capita livestock holdings were determined for the period 1980–2000, a period of fluctuating rainfall and primary production. Results For the first half of the twentieth century, the Mara was infested with tsetse‐flies, and the Maasai were confined to the Lemek Valley area to the north of the MMNR. During the early 1960s, active tsetse‐control measures by both government and the Maasai led to the destruction of woodlands across the Mara and the retreat of tsetse flies. The Maasai were then able to expand their settlement area south towards MMNR. Meanwhile, wildebeest (Connochaetes taurinus) from the increasing Serengeti population began to spill into the Mara rangelands each dry season, leading to direct competition between livestock and wildlife. Group ranches were established in the area in 1970 to formalize land tenure for the Maasai. By the late 1980s, with rapid population growth, new settlement areas had been established at Talek and other parts adjacent to the MMNR. Over the period 1983–99, the number of Maasai bomas in Koyake has increased at 6.4% per annum (pa), and the human population at 4.4% pa. Over the same period, cattle numbers on Koyake varied from 20,000 to 45,000 (average 25,000), in relation to total rainfall received over the previous 2 years. The rangelands of the Mara cannot support a greater cattle population under current pastoral practices. Conclusions With the rapid increase in human settlement in the Mara, and with imminent land privatization, it is probable that wildlife populations on Koyake will decline significantly in the next 3–5 years. Per capita livestock holdings on the ranch have now fallen to three livestock units/reference adult, well below minimum pastoral subsistence requirements. During the 1980s and 90s the Maasai diversified their livelihoods to generate revenues from tourism, small‐scale agriculture and land‐leases for mechanized cultivation. However, there is a massive imbalance in tourism incomes in favour of a small elite. In 1999 the membership of Koyake voted to subdivide the ranch into individual holdings. In 2003 the subdivision survey allocated plots of 60 ha average size to 1020 ranch members. This land privatization may result in increased cultivation and fencing, the exclusion of wildlife, and the decline of tourism as a revenue generator. This unique pastoral/wildlife system will shortly be lost unless land holdings can be managed to maintain the free movement of livestock and wildlife.     

Political Change and Factors Limiting Numbers of Wild and Domestic Ungulates in Kazakhstan

We examine factors regulating numbers of domestic livestock and saiga antelopes during the major periods of Kazakhstan's history. In the pre-Soviet period livestock migrations were relatively unrestricted and covered huge distances. Little winter feed or veterinary care was provided for domestic livestock and numbers were regulated largely by winter snow or ice cover. Drought affected fecundity but did not cause large-scale mortality. During the Soviet period the provision of winter feed shielded domestic livestock from winter mortality while hunting controls allowed saiga numbers to recover from overhunting. Livestock and saiga numbers during this period were high and there is evidence that productivity was affected. However, there were no crashes in livestock numbers linked to high densities, probably because rainfall variability is relatively low and catastrophic droughts are rare. Today livestock numbers in Kazakhstan have crashed because of the withdrawal of state support and the use of animals as currency. The collapse of the state also meant the end of hunting controls and increased poverty, which has lead to widespread saiga poaching and dramatic population declines.     

Are cattle,sheep, and goats endangered species?

For about 10 000 years, farmers have been managing cattle, sheep, and goats in a sustainable way, leading to animals that are well adapted to the local conditions. About 200 years ago, the situation started to change dramatically, with the rise of the concept of breed. All animals from the same breed began to be selected for the same phenotypic characteristics, and reproduction among breeds was seriously reduced. This corresponded to a strong fragmentation of the initial populations. A few decades ago, the selection pressures were increased again in order to further improve productivity, without enough emphasis on the preservation of the overall genetic diversity. The efficiency of modern selection methods successfully increased the production, but with a dramatic loss of genetic variability. Many industrial breeds now suffer from inbreeding, with effective population sizes falling below 50. With the development of these industrial breeds came economic pressure on farmers to abandon their traditional breeds, and many of these have recently become extinct as a result. This means that genetic resources in cattle, sheep, and goats are highly endangered, particularly in developed countries. It is therefore important to take measures that promote a sustainable management of these genetic resources; first, by in situ preservation of endangered breeds; second, by using selection programmes to restore the genetic diversity of industrial breeds; and finally, by protecting the wild relatives that might provide useful genetic resources.     

Livestock damage and wolf presence

Depredation on livestock and wolf pack Canis lupus distribution was investigated in the province of Arezzo, Tuscany, from 1998 to 2001. Although livestock was uniformly distributed, damage level and distribution were focused in the mountainous area inhabited by wolf packs hence there were huge differences between areas with and without wolves. In the whole province a few farms were persistently affected by predation (6%), and they reported 38% of the total attacks and 37% of the total losses. Surplus killing phenomena involved only sheep and goat farms, affecting 18% of the total. Thirty-five attacks (14% of the total attacks) reported 536 kills (44% of the total livestock killed in the whole province of Arezzo). During the period 1998–2001, compensation costs in the province averaged 86 863 Euros (range: 68 805–99 318 Euros). In the same period, no farmer requested prevention funding from the Tuscan region. During the study period wolf population was stable: wolf packs were distributed on 47% of the whole province (1504 km²), with a density estimated at 2.9±0.7 wolves 100 km⁻².     

Habitat choice of Grevy's zebras (Equus grevyi) in Laikipia, Kenya

Characterizing habitat choice is essential for endangered species conservation. For the endangered Grevy's zebra ( Equus grevyi ), as with many widely ranging vertebrates, human activities may be an important factor affecting space use. Grevy's zebras are grazing ungulates inhabiting the savannahs of central-northern Kenya and Ethiopia. Past research on their social organization indicates that reproductive status shapes associations and movements. Here, we examine how habitat use varies across four reproductive classes: lactating and nonlactating females, bachelors and territorial males. We also test whether Grevy's zebra avoid locations close to active livestock corrals, or bomas . We find that forage quality, forage quantity and habitat openness of locations used by Grevy's zebra vary significantly depending on individual reproductive state. Lactating females and bachelors use areas with green, short grass and medium-dense bush more frequently than nonlactating females or territorial males. We hypothesize that lactating females trade off forage quantity and safety to access nutrients in growing grass. Across reproductive classes, Grevy's zebra choose locations further from active bomas than if they used the area randomly. Our results suggest that Grevy's zebra may require a range of vegetation characteristics for different reproductive classes. Further, they may need areas free from competition or disturbance by livestock.