An increase in livestock density increases forage nutritional value but decreases net primary production and annual forage nutritional yield in the alpine grassland of the Qinghai-Tibetan Plateau

Pasture biomass and quality are dependent on herbivore grazing andprecipitation, but the responses of vegetation to the interactive effects ofclimate and grazing regimes remain unclear. We conducted an eight-yearsheep grazing experiment with 4 stocking rates (0, 3.5, 5.5, and 7.5 sheep/ha) inan alpine meadow of the northeastern Tibetan Plateau. The above-ground netprimary productivity (ANPP) and forage nutritional value (FNV) of four dominantspecies (Poa annua, Kobresia humilis, Astragalus adsurgens and Potentillafruticosa) were measured during a wet year (360 mm rainfall) and a droughtyear (216 mm rainfall). The FNV was used as indicator of forage quality and wascalculated from the crude protein (CP) content, in vitro true dry matterdigestibility (IVTD), metabolic energy (ME) yield, and neutral detergent fiber(NDF) content of the plant. The stocking rate explained a minimum of 76% ofthe variations of ANPP, and the precipitation sub-additive effect for ANPPranged from 5% to 12%. The interaction of sheep stocking rate and precipitationaffected ANPP of the 4 species, except for P. fruticosa. The FNV of the pastureincreased with increasing grazing pressure, but ANPP and forage nutritionalyield (FNY) decreased. In calculating FNY, the increase in FNV did notcompensate for the decrease in ANPP. In non-grazed plots, the CP yielddeclined sharply (18%-55%) in response to drought, but there was no effecton ME yield. The interaction between stocking rate and precipitation affected forage quality of the 4 plant species differently. The grassland ANPP and FNYcould be maintained at a grazing intensity of 3.5 sheep/ha in wet and dry years.Our results highlight that stocking density affects pasture ANPP and FNV, and iscontingent on rainfal

Do Fleas Affect Energy Expenditure of Their Free-Living Hosts?

Parasites can cause energetically costly behavioural and immunological responses which potentially can reduce host fitness. However, although most laboratory studies indicate that the metabolic rate of the host increases with parasite infestation, this has never been shown in free-living host populations. In fact, studies thus far have shown no effect of parasitism on field metabolic rate (FMR).We tested the effect of parasites on the energy expenditure of a host by measuring FMR using doubly-labelled water in free-living Baluchistan gerbils (Gerbillus nanus) infested by naturally occurring fleas during winter, spring and summer. We showed for the first time that FMR of free-living G. nanus was significantly and positively correlated with parasite load in spring when parasite load was highest; this relationship approached significance in summer when parasite load was lowest but was insignificant in winter. Among seasons, winter FMRs were highest and summer FMRs were lowest in G. nanus.The lack of parasite effect on FMR in winter could be related to the fact that FMR rates were highest among seasons. In this season, thermoregulatory costs are high which may indicate that less energy could be allocated to defend against parasites or to compensate for other costly activities. The question about the cost of parasitism in nature is now one of the major themes in ecological physiology. Our study supports the hypothesis that parasites can elevate FMR of their hosts, at least under certain conditions. However, the effect is complex and factors such as season and parasite load are involved

Fish traders in artisanal fisheries on the Kenyan coast

Purpose – Marine fisheries are one of the few economic activities present everywhere along the Kenyan coastline. The local population is involved mainly in artisanal fishing which uses small non-motorized fishing crafts that stay close to shore. Some of the catch is destined for local consumption but most is for sale. The purpose of this paper is to question whether fish traders in artisanal fisheries along the Kenyan coast earn enough money from only fish trading to support a household. Design/methodology/approach – Fish traders were surveyed at two landing sites at each of five coastal tracts. Structured questionnaires, informal interviews and participatory observations were used in collecting data. Findings – Average income for the fish traders from only fish trading was Ksh 1,268 per week; only 20.3 percent of the households was at or above the poverty line. However, there was a large difference between male and female traders in earning. Men earned Ksh 1,693 per week and women Ksh 795 per week. The poverty line for households was reached by 30.8 percent of the male traders but only by 8.8 percent of the female traders. Originality/value – Livelihood diversification could greatly help improve the income. It was estimated that when earnings other than from fish trading (from the traders or someone else in the household) were added to that of fish trading, 27.4 percent of the households was at or above the poverty line. For men traders, it was 54 percent of the households but for women it was only 15 percent.Coastal regions, Fishing, Gender, Kenya, Trade