Mechanisms linking plant diversity to large herbivore performance

There is established concern that loss of biodiversity will affect ecosystem productivity, nutrient cycling, carbon storage, stability and other properties^1,2^. Interactions between trophic levels are thought to link changes to biodiversity and ecosystem processes^3-6^. However, there is a lack of empirical studies linking plant diversity with altered trophic levels^7,8^, especially for large herbivores, the important but often neglected, controlling trophic level in terrestrial systems. Here we examine responses in performance of the large generalist herbivore to changes in plant diversity, using an indoor cafeteria trial and a field experiment. Our results show that increased plant diversity improves herbivore performance but it is depressed at highest plant diversity levels. We propose the Disturbance Selection Hypothesis for explaining plant diversity effects on primary consumers. Increasing the number of plant species in grassland, increases consumption and enhances nutrient intake (presumably improving animal fitness) by modifying nutrient balance, toxin dilution and taste modulation. High plant diversity simultaneously intensifies animal diet switching frequency, and weakens the herbivore's ability to select food, thereby increasing foraging cost and disturbing the herbivore's selection of forage. Thus, the consequence of plant diversity for large herbivore performance depends on the trade-off between the positive and negative effects. At highest plant diversity the positive effects weaken and negative effects strengthen. We suggest knowledge of the mechanisms is the means for understanding relationships between biodiversity and ecosystem functioning, and the management of large herbivores on rangelands used for conservation and grazing

Plant and Animal Responses to Different Grazing Regimes on a Meadow Steppe in Northeast China

Grazing by domestic herbivores is often considered to be an essential factor governing grassland vegetation and animal production (Hodgson and Illius 1996). During recent decades, there is increasing interest as a fundamental interaction between plant-animal interface, especially for the simultaneous or interactive responses of plants and animals to grassland grazing regimes (Liu et al., 2015), which benefits on improving the efficiency of grazing or grassland resource management. To achieve sustainable animal productivity and maintain the stability of grasslands, farmers or stakeholders need to employ optimal grazing strategies or regimes based on practical grassland vegetation and environments. Unfortunately, up to date it remains unclear what grazing regime will favour animal production, and mitigate the grassland degradation resulted from long-term free grazing in the eastern areas of the Eurasian Steppe. For this study, we conducted a five-year grazing experiment to test how grazing intensity (mediate and heavy) interact with resting to impact on the performance of plants and animals in a meadow steppe, and estimate the effects of designed grazing regime in this region

Between concrete and abstract: the Malaysian Chinese way of naming dishes

The Chinese pay considerable attention to the naming of dishes. While coming up with a well-prepared cuisine is considered as an artwork, giving it a suitable name is no different from adding the touch that brings a work of art to life. In naming a dish, the community utilizes its linguistic and non-linguistic resources. Dish names are hence a group of living fossils supporting the notion of language reflecting society. Using 1077 samples of dish names collected from Malaysian Chinese weddings and the lunar new year celebration, the present paper aims to investigate the concrete and abstract naming of Chinese dishes, and discuss the common cultural considerations underlying them. It was found that concrete naming deals with the tangible aspects of a dish by incorporating method of preparation, taste/aroma, appearance of dish, as well as container used; while abstract naming draws support from four-character idioms, legends/historical events, auspicious words, Chinese auspicious objects and legendary animals, and homophones, with cultural considerations playing a major if not the sole role in it

Large herbivores facilitate a dominant grassland forb via multiple indirect effects

While large herbivores are critically important components of terrestrial ecosystems and can have pronounced top-down effects on plants, our understanding of the underlying mechanisms driving these effects remains incomplete. Large herbivores can alter plant growth, reproduction, and abundance through direct effects (predominantly consumption) and through indirect effects via altered interactions with abiotic factors and other species. We know considerably less about these indirect effects than the direct effects. Here, we integrate medium- and small-scale field experiments to investigate how a large vertebrate herbivore, cattle (Bos taurus), affects the aboveground biomass of a dominant forb species, Artemisia scoparia, via diverse direct and indirect pathways in a temperate grassland in northeast China. Although cattle consumed this forb, its biomass increased significantly in response to grazing, due to multiple indirect positive effects that outweighed the direct negative effects of consumption. Cattle preferentially consumed the competing grass Leymus chinensis, and altered Artemisia microhabitats by reducing total plant cover and litter biomass and by increasing the abundance of co-occurring ant species (e.g., Formica spp. and Lasius spp.). This led to additional indirect positive effects on A. scoparia likely due to (1) increased light availability in understory layers and other limiting resources (e.g., soil nutrients and moisture) caused by removal of competitors and plant litter at the soil surface and (2) the changes in resource availability (e.g., soil nutrients and moisture) associated with ant colonies. Our results show that large herbivores can affect plant growth not only via direct consumption, but also via multiple indirect effects. Focusing on the causes and consequences of herbivore-induced indirect effects will not only help us to better understand the influence of these animals in ecological systems, but will also lead to more effective land management and conservation practices in the regions they inhabit

Between concrete and abstract: the Malaysian chinese way of naming dishes

The Chinese pay considerable attention to the naming of dishes. While coming up with a well-prepared cuisine is considered as an artwork, giving it a suitable name is no different from adding the touch that brings a work of art to life. In naming a dish, the community utilizes its linguistic and non-linguistic resources. Dish names are hence a group of living fossils supporting the notion of language reflecting society. Using 1077 samples of dish names collected from Malaysian Chinese weddings and the lunar new year celebration, the present paper aims to investigate the concrete and abstract naming of Chinese dishes, and discuss the common cultural considerations underlying them. It was found that concrete naming deals with the tangible aspects of a dish by incorporating method of preparation, taste/aroma, appearance of dish, as well as container used; while abstract naming draws support from four-character idioms, legends/historical events, auspicious words, Chinese auspicious objects and legendary animals, and homophones, with cultural considerations playing a major if not the sole role in it

Reciprocal facilitation between large herbivores and ants in a semi-arid grassland

While positive interactions have been well documented in plant and sessile benthic marine communities, their role in structuring mobile animal communities and underlying mechanisms has been less explored. Using field removal experiments, we demonstrated that a large vertebrate herbivore (cattle; Bos taurus) and a much smaller invertebrate (ants; Lasius spp.), the two dominant animal taxa in a semi-arid grassland in Northeast China, facilitate each other. Cattle grazing led to higher ant mound abundance compared with ungrazed sites, while the presence of ant mounds increased the foraging of cattle during the peak of the growing season. Mechanistically, these reciprocal positive effects were driven by habitat amelioration and resource (food) enhancement by cattle and ants (respectively). Cattle facilitated ants, probably by decreasing plant litter accumulation by herbivory and trampling, allowing more light to reach the soil surface leading to microclimatic conditions that favour ants. Ants facilitated cattle probably by increasing soil nutrients via bioturbation, increasing food (plant) biomass and quality (nitrogen content) for cattle. Our study demonstrates reciprocal facilitative interactions between two animal species from phylogenetically very distant taxa. Such reciprocal positive interactions may be more common in animal communities than so far assumed, and they should receive more attention to improve our understanding of species coexistence and animal community assembly.</p

Diversifying livestock promotes multidiversity and multifunctionality in managed grasslands

Increasing plant diversity can increase ecosystem functioning, stability, and services in both natural and managed grasslands, but the effects of herbivore diversity, and especially of livestock diversity, remain underexplored. Given that managed grazing is the most extensive land use worldwide, and that land managers can readily change livestock diversity, we experimentally tested how livestock diversification (sheep, cattle, or both) influenced multidiversity (the diversity of plants, insects, soil microbes, and nematodes) and ecosystem multifunctionality (including plant biomass production, plant leaf N and P, above-ground insect abundance, nutrient cycling, soil C stocks, water regulation, and plant-microbe symbiosis) in the world's largest remaining grassland. We also considered the potential dependence of ecosystem multifunctionality on multidiversity. We found that livestock diversification substantially increased ecosystem multifunctionality by increasing multidiversity. The link between multidiversity and ecosystem multifunctionality was always stronger than the link between single diversity components and functions. Our work provides insights into the importance of multitrophic diversity to maintain multifunctionality in managed ecosystems and suggests that diversifying livestock could promote both multidiversity and ecosystem multifunctionality in an increasingly managed world

Livestock overgrazing disrupts the positive associations between soil biodiversity and nitrogen availability

8 páginas.- 4 figuras.- 1 tabla.- 64 referencias.- Additional supporting information may be found online in the Supporting Information sectionLivestock overgrazing influences both microbial communities and nutrient cycling in terrestrial ecosystems. However, the role of overgrazing in regulating the relationship between soil biodiversity and nitrogen availability remains largely unexplored.We performed long-term grazing exclusion experiments across eight sites along precipitation gradient covering three major types of grassland in northern China to compare the linkage between soil microbial diversity and N availability in overgrazed versus non-grazed conditions.We found a significantly positive association between fungal diversity and soil available N in non-grazed grasslands. However, the positive association was absent in overgrazed environments. Bacterial diversity is not related to soil available N in either non-grazed or overgrazed grasslands. Moreover, in bacterial community, we found a positive link between the relative abundance of Actinobacteria with soil available N in non-grazed, but not overgrazed, grasslands. Instead we found the links between relative abundance of Bacteroidetes and Acidobacteria with soil available N in overgrazed grasslands, but not non-grazed, grasslands.Synthesis. Our work provides evidence that the relationships between microbial diversity and ecosystem functions are context-dependent, and so microbial community diversity is likely not the major driver of soil N mineralization in overgrazed grasslands. Our study suggests that high intensity anthropogenic activities in grasslands restrains the capacity of diverse soil microbial communities to sustain ecosystem function, and more broadly the capacity of entire ecosystems to maintain important ecosystem processes such as plant production. Our study also indicates that the fundamental microbial communities associated with N availability change with differing land management strategies (e.g. livestock grazing).National Natural Science Foundation of China, Grant/Award Number: 31772652, U1603235, 31660679 and 31770500; National Key Research and Development Program of China, Grant/Award Number: 2016YFC0500602; Program for Introducing Talents to Universities, Grant/Award Number: B16011; Ministry of Education Innovation Team Development Plan, Grant/Award Number: 2013-373; Innovative Team of Grassland Resources from the Ministry of Education of China, Grant/Award Number: IRT_17R59; Horizon 2020 Framework Program, Grant/Award Number: H2020-MSCA-IF-2016Peer reviewe

Livestock grazing impacts on plateau pika (Ochotona curzoniae) vary by species identity

Livestock and small burrowing mammals are potential ecosystem engineers and major drivers of ecosystem processes. Small mammals, often considered competitors with livestock, have been reported to increase in recent years and have been identified for their negative impacts on ecosystem services such as plant production and soil carbon sequestration. However, these increases and impacts by small mammals have rarely been studied with respect to how they may be influenced by livestock grazing. Here we experimentally manipulated large enclosures on the alpine grassland of Qinghai-Tibetan plateau, each with different livestock assemblages: yak (Bos grunniens), Tibetan sheep (Ovis aries), mixed populations of yak and sheep, and a control plot containing no livestock to study the potential impacts of livestock on the dominant small mammalian herbivore in the region, the plateau pikas (Ochotona curzoniae). We found that during the period of peak vegetative growth all pika populations in livestock experimental plots increased compared with those in the control plots. Additionally, pika populations and active pika burrow density increased more in experimental plots containing yaks compared with the sheep-only experimental plots. These results provide evidence that livestock grazing can increase the risk of pika outbreaks, which has led to this species being classified as a pest and subject to widespread control measures. We suggest explicitly incorporating livestock species identity in addition to grazing intensity and duration into management considerations to ensure maintenance of native biodiversity and long-term sustainability on the alpine grasslands of the Qinghai-Tibetan plateau.</p