J. Isselstein

Plant Biodiversity and Ethnobotany of Borana Pastoralists in Southern Oromia, Ethiopia

A survey of plant biodiversity and ethnobotanical studies was conducted in southern Ethiopia using an integrated approach of botanical collections, group discussions, interviews and questionnaires. Species richness, growth forms and uses of native wild plants are described. Borana pastoralists distinguished and named 86% of the plant species identified. A total of 327 plant species distributed among 197 genera and 69 families are documented: 40% are trees/shrubs, 30% forbs (non-woody plants other than grasses and sedges), 16% grasses, 10% climbers, 2% sedges and 2% succulents. Based on richness of species and usefulness, the most important families are Poaceae, Fabaceae, Lamiaceae and Asteraceae. Two hundred forty-eight species (76%) are used by Borana pastoralists, out of which 42% have multiple uses. Indigenous knowledge of pastoralists on use and management of their plant resources is a valuable source of information for conservation and sustainable utilization of the plant biodiversity and, hence, conservation based on indigenous knowledge is recommended.

Future consequences and challenges for dairy cow production systems arising from climate change in Central Europe - a review

It is well documented that global warming is unequivocal. Dairy production systems are considered as important sources of greenhouse gas emissions; however, little is known about the sensitivity and vulnerability of these production systems themselves to climate warming. This review brings different aspects of dairy cow production in Central Europe into focus, with a holistic approach to emphasize potential future consequences and challenges arising from climate change. With the current understanding of the effects of climate change, it is expected that yield of forage per hectare will be influenced positively, whereas quality will mainly depend on water availability and soil characteristics. Thus, the botanical composition of future grassland should include species that are able to withstand the changing conditions (e.g. lucerne and birds foot trefoil). Changes in nutrient concentration of forage plants, elevated heat loads and altered feeding patterns of animals may influence rumen physiology. Several promising nutritional strategies are available to lower potential negative impacts of climate change on dairy cow nutrition and performance. Adjustment of feeding and drinking regimes, diet composition and additive supplementation can contribute to the maintenance of adequate dairy cow nutrition and performance. Provision of adequate shade and cooling will reduce the direct effects of heat stress. As estimated genetic parameters are promising, heat stress tolerance as a functional trait may be included into breeding programmes. Indirect effects of global warming on the health and welfare of animals seem to be more complicated and thus are less predictable. As the epidemiology of certain gastrointestinal nematodes and liver fluke is favourably influenced by increased temperature and humidity, relations between climate change and disease dynamics should be followed closely. Under current conditions, climate change associated economic impacts are estimated to be neutral if some form of adaptation is integrated. Therefore, it is essential to establish and adopt mitigation strategies covering available tools from management, nutrition, health and plant and animal breeding to cope with the future consequences of climate change on dairy farming.

Seedling recruitment on agriculturally improved mesic grassland: the influence of disturbance and management schemes

Abstract Question: Are the recruitment patterns of deliberately introduced wildflower species influenced by cutting frequencies and disturbance treatments? To what extent do these different treatments affect productivity and sward structure of an agriculturally improved grassland? Location: A mesic lowland grassland near Göttingen, Lower Saxony, Germany. Methods: Recruitment success of eight sown wildflower species was studied in a permanent grassland treated by a factorial combination of different pre-sowing cutting intervals (1, 3 or 9 wk), post-sowing cutting intervals (1, 3 or 9 wk) and disturbance (control, harrowing, removal of sward). Seedling emergence and survival, biomass production and sward structure were followed over two years. Results: For most species seedling emergence was highest in the harrowing treatment. The complete sward removal did not further increase seedling emergence. Seedling survival was strongly influenced by the post-sowing cutting frequency with highest mortality in the 9 wk cutting interval compared to one and 3 wk cutting intervals. Annual dry matter yield varied between 4.4, 5.9 and 9.4 t.ha−1 in the 1, 3 and 9 wk pre-sowing cutting treatment, respectively. In June, when the seeds were sown, the tiller number of the 1 wk cut plots was twice as high as for the 9 wk cut plots and five times higher than in the harrowing treatment. Conclusions: Disturbance by harrowing provided the optimal environmental cues to trigger germination, whereas seedling survival was facilitated by increased light penetration due to frequent cutting. The investigation revealed the overriding importance of frequent standing crop removal in the early phase of seedling establishment on agriculturally improved grassland. Nomenclature: Oberdorfer (1994).

Rewards for ecological goods—requirements and perspectives for agricultural land use

Abstract This paper focuses on the possibilities to reward ecological goods and services of agriculture. Ecological goods in agriculture are achieved by various types of agricultural land use either creating resources or buffering resource consumption. From an economic point of view, positive consequences will result from rewarding the agricultural sector for the production of ecological goods according to market principles. A rewarding system can be developed according to market principles when results instead of actions are rewarded, producer and consumer surpluses are created, demand can be expressed and supply can be provided. Ecological goods are public goods, therefore the expression of demand is up to the community. However, the purchasing of such ecological goods is up to the authority administrating public finances. Establishing regional markets is necessary, since regional differences are evident. Principally, the price of an ecological good should be determined by its value to the public, not by the cost of production. With respect to the various ecological goods achieved by the agricultural sector, the contribution of agricultural land use to biodiversity, and more specifically to plant biodiversity seems to be the most appropriate for a market-orientated rewarding system. A framework for establishing such a market is outlined in this paper. Deviation from standard economic principles regarding prices for ecological goods are considered to be necessary during an introductory period. Finally based on both, ecological and economical considerations, and regarding the intrinsic and extrinsic characteristics of “plant biodiversity connected with agricultural land use”, it seems worth the effort to further examine and develop this concept.

Phytodiversity of temperate permanent grasslands: ecosystem services for agriculture and livestock management for diversity conservation

Plant diversity has been reported to increase productivity. Farming practices aiming at conserving or increasing plant diversity are, however, usually less profitable than conventional ones. In this review, we aim to find reasons for this discrepancy, discuss ecosystem services of grassland phytodiversity that are useful for farmers, and ways of livestock management most beneficial for diversity. Under agricultural conditions, a clear effect of species richness on a site’s primary or secondary production has not yet been demonstrated. Reasons could be that species numbers in permanent grassland are above the threshold of five species found effective in experimental plots or that the conditions are more in equilibrium with management than in weeded experimental plots. Other diversity effects on production stability, nutrient and water retention or product quality might convince farmers to increase diversity. However, these should be tested in agricultural situations, as most research has again been carried out in experimental plots. To enhance phytodiversity, grazing has been found superior over mowing, as selective grazing, treading and excreta deposition increase the heterogeneity of a sward and thus the niches available. Especially rotational grazing with intermediate intensity may be advantageous for phytodiversity. However, complex interactions between environmental conditions, sward composition, management and livestock behaviour make it difficult to forecast grazing effects. Thus, ecological and agricultural researchers should cooperate more, e.g. either in interdisciplinary projects or by hiring researchers from the respective other profession and thus diversifying research groups, in order to integrate agricultural management into biodiversity research and biodiversity measurements into agricultural research to advance our understanding of how to make conservation and enhancement of grassland phytodiversity both feasible and sustainable.

The effects of a ration change from a total mixed ration to pasture on health and production of dairy cows

In pasture-based dairy production systems, dairy cows often receive a silage- and concentrate-based ration [total mixed ration (TMR)] during wintertime and are gradually introduced to fresh herbage in spring. The present study aimed to investigate how the transition to this new nutritional situation influenced different production and health indicators. A 10-wk trial was performed in spring 2014, including 60 dairy cows of the German Holstein breed (166±23 d in milk, 23.5±3.7 kg of milk/d; means ± SD). The cows were divided into a pasture and a confinement group (PG and CG, respectively). The CG stayed on a TMR-based diet (35% corn silage, 35% grass silage, 30% concentrate; DM basis), whereas the PG was gradually transitioned from a TMR- to a pasture-based ration (wk 1=TMR-only, wk 2=3 h/d on pasture, wk 3 and 4=12 h/d on pasture, wk 5-10=pasture-only). A continuous grazing system was implemented on a ryegrass dominated pasture and temperature humidity indices were assessed based on continuous recording of temperature and humidity indoors as well as outdoors. Dry matter intake (DMI) from TMR, milk production, body weight (BW), and body condition score decreased as soon as the PG had partial access to pasture. Milk production and BW decreased even further in the first week on a full grazing ration, but thereafter BW increased again and milk production stabilized. The DMI estimation using the n-alkane method in wk 7 and 9 revealed an increase in DMI from pasture between the 2 time points and indicates an adaptation of grazing behavior and metabolism over several weeks. Increased serum β-hydroxybutyrate and fatty acids concentrations at several time points, as well as a continuous body condition score decrease during the whole course of the trial, indicate an energy deficit in the PG. A significant correlation between serum glucose concentrations and the temperature humidity indices was observed. An increase in serum and milk urea concentrations as well as an increase in the urine total N to creatinine ratio occurred in the PG. To assess possible negative effects of the ration change on metabolic and liver health, different clinical chemistry variables and complete blood counts were assessed. No biologically relevant changes were observed for serum albumin, total protein, cholesterol, aspartate transaminase, γ-glutamyltransferase, and glutamate dehydrogenase concentrations, as well as for white and red blood cell counts.

Effects of herbicide application to control sward composition in different management variants

Abstract Herbicide application on permanent grassland to reduce weeds and improve forage quality is common agricultural practice. However, it still remains unclear how long it takes for the herbicide-disturbed swards to recover in terms of yield and forage quality. In a removal experiment in the Solling Uplands (Germany), the sward composition of permanent grassland had been manipulated by herbicides in order to obtain either relatively pure grass swards or swards with comparatively large amounts of forbs and legumes, in addition to untreated control swards. The short-term resilience of these sward types was examined under a gradient of management intensity regulated by both cutting regime and fertilizer supply. In the next growing season, the yield did not differ among any of the three sward types regardless of the management regime. All disturbed swards showed a complete recovery in terms of biomass. Yield was only influenced by functional sward characteristics across all disturbance treatments; the growth form of the dominant species determined the yield in fertilized plots. For the variation in forage quality (crude protein, water-soluble carbohydrates and fibre content), the functional group identity of the remaining vegetation was important, but management had a much larger influence than vegetation.

Phosphorus, Plant Biodiversity and Climate Change

Phosphorus (P) is a major plant nutrient. Its increasing use as a fertilizer has helped to raise crop and fodder production. However, the global reserves and resources of P are finite, demanding an efficient use of P. Under natural conditions, it is often in limited supply. Plants have developed adaptations to small soil P concentrations. Increased P levels can have unwanted side effects like eutrophication and algal blooms. Besides, P concentrations in the soil have often been found to be negatively correlated with plant diversity. For sustainable agriculture, it is essential to understand (1) adaptations of plants to small P concentrations in soils to maintain production with decreasing P reserves, (2) influences of P on phytodiversity to minimize unwanted effects, and (3) future developments of P and phytodiversity in relation to climate change to adjust agricultural practices.

Isotopic composition of soil, vegetation or cattle hair no suitable indicator of nitrogen balances in permanent pasture

Stable isotope signatures of cattle tail switch hair or meadow vegetation have been found to be related to nitrogen (N) surpluses of whole farms and of meadows, respectively. Permanent pastures are more patchy in terms of nutrient inputs and outputs and N balances for the whole plot do not necessarily give correct impressions of losses. We here investigated correlations between isotopic signatures and N balances calculated for different spatial and temporal scales in permanent pastures. N concentrations and δ15N values of cattle tail switch hair, vegetation and soil samples were measured in an experiment with different grazing intensities started in 2002. Results were compared to soil surface balances calculated for the whole plot or for plot areas affected by either dung, urine, grazing without excreta input, or the pasture area without dung pats. There were no significant correlations between plant or cattle hair isotopic signatures and any of the balances. N fixation probably influenced vegetation signatures, making the isotopic values less dependent on soil and more on atmospheric N. The cattle preferred short mixed vegetation with more legume biomass, which also influenced the 15N values of their hair. The 15N signatures of soil samples were the best indicators of partial N balances in these heterogeneous pastures, probably because soil values are most directly influenced by N inputs and outputs. Still, soil signatures only explained between 15 and 35% of the variation in balance results. Thus, none of the tested parameters can be used as a reliable indicator of N balance results in this heterogeneous system with small differences in budgets among treatments and potentially small plot-scale N losses.

Nitrogen excretion of adult sheep fed silages made of a mixed sward or of pure unfertilised grass alone and in combination with barley

Four adult rumen-fistulated wether sheep were fed silages combined with barley. The silages consisted of 48% grasses, 28% legumes and 24% other forbs (GCF) or of pure grass (G). The swards received no mineral fertiliser. The dry matter (DM) and fibre contents were lower in GCF than in G. Crude protein content of DM in GCF and G were 145 g/kg and 102 g/kg respectively. DM content as ash, lipids and non-fibrous carbohydrates were rather similar in both silages. About 40g DM were offered per kg BW0.75 and day either as silage alone or as a mixture of silage and barley (60:40). Faecal N excretion was greater with GCF than with G. The proportion of faecal bacterial and endogenous debris N reached 75 and 73% when GCF or G was fed, respectively. Undigested dietary N represented about 20%, and water soluble N accounted for 5–6% of faecal N. GCF caused more urinary N than G. Barley reduced urinary N excretion when supplemented to GCF. No dietary influence on urinary non-urea nitrogenous compounds was shown. GCF caused higher urinary urea N excretion than G and barley reduced this fraction when replacing part of GCF. Based on the urinary urea N proportions, it is concluded that N intake exceeded N requirement for any of the four diets fed. Dietary supplementation of ruminally fermentable carbohydrates can reduce urinary N excretion and this improves the efficiency of utilisation of N in N-unfertilised biodiverse grassland/ruminant farming systems.