Carbon sequestration in Himalaya's alpine meadows: Mitigating cropping encroachment on pastures in Northern Pakistan

Rangelands store about 30% of the world’s carbon and support over 120 million pastoralists globally. Adjusting the management of remote alpine pastures bears a substantial climate change mitigation potential that can provide livelihood support for marginalized pastoralists through carbon payment. Landless pastoralists in Northern Pakistan seek higher income by cropping potatoes and peas over alpine pastures. However, tilling steep slopes without terracing exposes soil to erosion. Moreover, yields decline rapidly requiring increasing fertilizer inputs. Under these conditions, carbon payment could be a feasible option to compensate pastoralists for renouncing hazardous cropping while favoring pastoral activities. The study quantifies and compares C on cropped and grazed land. The hypothesis was that cropping on alpine pastures reduces former carbon storage. The study area located in the Naran valley of the Pakistani Himalayas receives an annual average of 819 mm of rain and 764 mm of snow. Average temperatures remain below 0°C from November to March while frost may occur all year round. A total of 72 soil core samples were collected discriminating land use (cropping, pasture), aspect (North, South), elevation (low 3000, middle 3100, and high 3200 m a.s.l.), and soil depth (shallow 0-10, deep 10-30 cm). Thirty six biomass samples were collected over the same independent variables (except for soil depth) using a 10x10x20 cm steal box inserted in the ground for each sample. Aboveground biomass and coarse roots were separated from the soil aggregate and oven-dried. Soil organic carbon (SOC) and biomass carbon (BC) were estimated through a potassium dichromate oxidation treatment. The samples were collected during the second week of October 2010 at the end of the grazing and cropping season and before the first snowfall. The data was statistically analyzed by means of a one-way analysis of variance. Results show that all variables taken separately have a significant effect on mean SOC [%]: crop/pasture 1.33/1.6, North/South 1.61/1.32, low/middle/high 1.09/1.62/1.68, shallow/deep 1.4/1.53. However, for BC, only land use has a significant effect with more than twice the amount of carbon in pastures [g m-2]: crop/pasture 127/318. These preliminary findings suggest that preventing the conversion of pastures into cropping fields in the Naran valley avoids an average loss of 12.2 t C ha-1 or 44.8 t CO2eq ha-1 representing a foreseeable compensation of 672 € ha-1 for the Naran landless pastoralists who would renounce cropping. The ongoing study shall provide a complete picture for carbon payment integrating key aspects such as the rate of cropping encroachment over pastures per year, the methane leakage from the system due to livestock enteric fermentation, the expected cropping income vs. livestock income and the transaction costs of implementing the mitigation project, certifying it, and verifying carbon credits. A net present value over an infinite time horizon for the mitigation scenario shall be estimated on an iterative simulation to consider weather and price uncertainties. The study will also provide an estimate of the minimum price of carbon at which pastoralists would consider engaging in the mitigation activity.

Seed availability in hay meadows: Land-use intensification promotes seed rain but not the persistent seed bank

Intensification of land use in semi-natural hay meadows has resulted in a decrease in species diversity. This is often thought to be caused by the reduced establishment of plant species due to high competition for light under conditions of increased productivity. Sowing experiments in grasslands have found reliable evidence that diversity can also be constrained by seed availability, implying that processes influencing the production and persistence of seeds may be important for the functioning of ecosystems. So far, the effects of land-use intensification on the seed rain and the persistence of seeds in the soil have been unclear. We selected six pairs of extensively managed (Festuco-Brometea) and intensively managed (Arrhenatheretalia) grassland with traditional late cutting regimes across Switzerland and covering an annual productivity gradient in the range 176–1211 gm−2. In each grassland community, we estimated seed rain and seed bank using eight pooled seed-trap or topsoil samples of 89 cm2 in each of six plots representing an area of c. 150 m2. The seed traps were established in spring 2010 and collected simultaneously with soil cores after an exposure of c. three months. We applied the emergence method in a cold frame over eight months to estimate density of viable seeds. With community productivity reflecting land-use intensification, the density and species richness in the seed rain increased, while mean seed size diminished and the proportions of persistent seeds and of species with persistent seeds in the topsoil declined. Stronger limitation of seeds in extensively managed semi-natural grasslands can explain the fact that such grasslands are not always richer in species than more intensively managed ones.

Delaying mowing and leaving uncut refuges boosts orthopterans in extensively managed meadows: Evidence drawn from field-scale experimentation

Semi-natural grasslands are widely recognized for their high ecological value. They often count among the most species-rich habitats, especially in traditional cultural landscapes. Maintaining and/or restoring them is a top priority, but nevertheless represents a real conservation challenge, especially regarding their invertebrate assemblages. The main goal of this study was to experimentally investigate the influence of four different mowing regimes on orthopteran communities and populations: (1) control meadow (C-meadow): mowing regime according to the Swiss regulations for extensively managed meadows declared as ecological compensation areas, i.e. first cut not before 15 June; (2) first cut not before 15 July (delayed treatment, D-meadow); (3) first cut not before 15 June and second cut not earlier than 8 weeks from the first cut (8W-meadow); (4) refuges left uncut on 10–20% of the meadow area (R-meadow). Data were collected two years after the introduction of these mowing treatments. Orthopteran densities from spring to early summer were five times higher in D-meadows, compared to C-meadows. In R-meadows, densities were, on average, twice as high as in C-meadows, while mean species richness was 23% higher in R-meadows than in C-meadows. Provided that farmers were given the appropriate financial incentives, the D- and R-meadow regimes could be relatively easy to implement within agri-environment schemes. Such meadows could deliver substantial benefits for functional biodiversity, including sustenance to many secondary consumers dependent on field invertebrates as staple food.

Reprint of "Seed availability in hay meadows: Land-use intensification promotes seed rain but not the persistent seed bank''

Intensification of land use in semi-natural hay meadows has resulted in a decrease in species diversity. This is often thought to be caused by the reduced establishment of plant species due to high competition for light under conditions of increased productivity. Sowing experiments in grasslands have found reliable evidence that diversity can also be constrained by seed availability, implying that processes influencing the production and persistence of seeds may be important for the functioning of ecosystems. So far, the effects of land-use intensification on the seed rain and the persistence of seeds in the soil have been unclear. We selected six pairs of extensively managed (Festuco-Brometea) and intensively managed (Arrhenatheretalia) grassland with traditional late cutting regimes across Switzerland and covering an annual productivity gradient in the range 176-1211 gm(-2). In each grassland community, we estimated seed rain and seed bank using eight pooled seed-trap or topsoil samples of 89 cm(2) in each of six plots representing an area of c. 150 m(2). The seed traps were established in spring 2010 and collected simultaneously with soil cores after an exposure of c. three months. We applied the emergence method in a cold frame over eight months to estimate density of viable seeds. With community productivity reflecting land-use intensification, the density and species richness in the seed rain increased, while mean seed size diminished and the proportions of persistent seeds and of species with persistent seeds in the topsoil declined. Stronger limitation of seeds in extensively managed semi-natural grasslands can explain the fact that such grasslands are not always richer in species than more intensively managed ones. (C) 2013 Elsevier B.V. All rights reserved.

Synthesis of Semi-Natural Grassland Vegetation of a Biogeographically Heterogeneous Area: Mesophilous Species-Rich Meadows in Switzerland

For a hundred years semi-natural species-rich meadow vegetation has been described from various areas of Switzerland. The first description dates from 1892 by Stebler and Schröter. In the present study, relevés of 65 semi-natural mesophilous meadow associations and communities reported by 26 authors, which were collected throughout the century, are summarized. An increasing number of descriptions dating from the 1980s and 1990s is included. A numerical classification of these 65 types resulted in four main groups of meadow-types. When compared with the existing literature of alliances a high correlation is found with the Polygono-Trisetion Br.-Bl. et R. Tx. ex Marshall 1947, the Arrhenatherion W. Koch 1926, the Agrostio-Festucion Puscaru et al. 1956, the Mesobromion Br.-Bl. et Moor 1938 em. Oberdorfer 1957, and with the Chrysopogonetum W. Koch 1943. The Agrostio-Festucion is characteristic for the montane belt in southern Switzerland and was until recently poorly known. This alliance is discussed in detail. Some classifications of meadow types by the original authors had to be rearranged for the present purpose. The present classification coincides well with the one Stebler and Schröter gave in 1892. Today, after a century of intensive changes in land use, their four main types are still valid.

Plant species decline due to abandonment of meadows cannot easily be reversed by mowing. A case study from the southern Alps

Abstract. We resumed mowing in two plots of ca. 100 m2 in an abandoned meadow dominated by Brachypodium pinnatum on the slope of Monte Generoso (Switzerland). We monitored species composition and hay yield using point quadrats and biomass samples. Species frequencies changed little during 10 yr (1988–1997) while hay yields showed large fluctuations according to mean relative humidity in April-June. We performed a seed-addition experiment to test whether the establishment of meadow species is limited by lack of diaspores or favourable microsites for germination and recruitment from the seed bank. We sowed ca. 12 000 seeds of 12 species originating from a nearby meadow individually in plots of a 4 × 6 unbalanced Latin square with four treatments, burning, mowing, mowing and removal of a layer of decayed organic matter, and a control. We monitored the fate of seedling individuals for 24 months. Seedlings of all species were established and survived for 12 months, 10 species survived during at least 24 months, some reached a reproductive stage. Species responded to different qualities of microsites provided by the different treatments thus required different regeneration niches. Spontaneous long-distance immigration was insignificant. We conclude that the former species composition of abandoned meadows cannot easily be restored by mowing alone because many plant species of meadows do not have persistent seed banks and immigration over distances of more than 25 m and successful establishment is very unlikely.

Does delaying the first mowing date benefit biodiversity in meadowland?

Background Meadows are regularly mown in order to provide fodder or litter for livestock and to prevent vegetation succession. However, the time of year at which meadows should be first mown in order to maximize biological diversity remains controversial and may vary with respect to context and focal taxa. We carried out a systematic review and meta-analysis on the effects of delaying the first mowing date upon plants and invertebrates in European meadowlands. Methods Following a CEE protocol, ISI Web of Science, Science Direct, JSTOR, Google and Google Scholar were searched. We recorded all studies that compared the species richness of plants, or the species richness or abundance of invertebrates, between grassland plots mown at a postponed date (treatment) vs plots mown earlier (control). In order to be included in the meta-analysis, compared plots had to be similar in all management respects, except the date of the first cut that was (mostly experimentally) manipulated. They were also to be located in the same meadow type. Meta-analyses applying Hedges’d statistic were performed. Results Plant species richness responded differently to the date to which mowing was postponed. Delaying mowing from spring to summer had a positive effect, while delaying either from spring to fall, or from early summer to later in the season had a negative effect. Invertebrates were expected to show a strong response to delayed mowing due to their dependence on sward structure, but only species richness showed a clearly significant positive response. Invertebrate abundance was positively influenced in only a few studies. Conclusions The present meta-analysis shows that in general delaying the first mowing date in European meadowlands has either positive or neutral effects on plant and invertebrate biodiversity (except for plant species richness when delaying from spring to fall or from early summer to later). Overall, there was also strong between-study heterogeneity, pointing to other major confounding factors, the elucidation of which requires further field experiments with both larger sample sizes and a distinction between taxon-specific and meadow-type-specific responses.

Globally dispersed Y chromosomal haplotypes in wild and domestic sheep

To date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. We present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine Y chromosome. Analysis of a single nucleotide polymorphism (oY1) in the SRY promoter region revealed that allele A-oY1 was present in all wild bighorn sheep (Ovis canadensis), two subspecies of thinhorn sheep (Ovis dalli), European Mouflon (Ovis musimon) and the Barbary (Ammontragis lervia). A-oY1 also had the highest frequency (71.4%) within 458 domestic sheep drawn from 65 breeds sampled from Africa, Asia, Australia, the Caribbean, Europe, the Middle East and Central Asia. Sequence analysis of a second locus, microsatellite SRYM18, revealed a compound repeat array displaying fixed differences, which identified bighorn and thinhorn sheep as distinct from the European Mouflon and domestic animals. Combined genotypic data identified 11 male-specific haplotypes that represented at least two separate lineages. Investigation of the geographical distribution of each haplotype revealed that one (H6) was both very common and widespread in the global sample of domestic breeds. The remaining haplotypes each displayed more restricted and informative distributions. For example, H5 was likely founded following the domestication of European breeds and was used to trace the recent transportation of animals to both the Caribbean and Australia. A high rate of Y chromosomal dispersal appears to have taken place during the development of domestic sheep as only 12.9% of the total observed variation was partitioned between major geographical regions.

The role of landuse and natural determinants for grassland vegetation composition in the Swiss Alps

The Alps provide a high habitat diversity for plant species, structured by broad- and fine-scale abiotic site conditions. In man-made grasslands, vegetation composition is additionally affected by the type of landuse. We recorded vegetation composition in 216 parcels of grassland in 12 municipalities representing an area of 170 x 70 km in the south-eastern part of the Swiss Alps. Each parcel was characterized by a combination of altitudinal level (valley, intermediate, alp). traditional landuse (mown. grazed), current management (mown, grazed, abandoned). and Fertilization (unfertilized, fertilized). For each parcel we also assessed the abiotic factors aspect, slope, pH value, and geographic coordinates, and for each municipality annual precipitation and its cultural tradition. We analysed vegetation composition using (i) variation partitioning in RDA. (ii) cover of graminoids. non-legume forbs, and legumes, and (iii) dominance and frequency of species. Species composition was determined by, in decreasing order of variation explained. landuse, broad-scale abiotic factors, fine-scale abiotic factors. and cultural tradition. Current socio-economically motivated landuse changes, such as grazing of unfertilized former meadows or their abandonment, strongly affect vegetation composition. In our study, the frequency of characteristic meadow species was significantly smaller in grazed and even smaller in abandoned parcels than in still mown ones, suggesting less severe consequences of grazing for vegetation composition than of abandonment. Therefore. low-intensity grazing and mowing every few years should be considered valuable conservation alternatives to abandonment. Furthermore. because each landuse type was characterized by different species. a high variety of landuse types should be promoted to preserve plant species diversity in Alpine grasslands. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.

Different Land Use Intensities in Grassland Ecosystems Drive Ecology of Microbial Communities Involved in Nitrogen Turnover in Soil

Understanding factors driving the ecology of N cycling microbial communities is of central importance for sustainable land use. In this study we report changes of abundance of denitrifiers, nitrifiers and nitrogen-fixing microorganisms (based on qPCR data for selected functional genes) in response to different land use intensity levels and the consequences for potential turnover rates. We investigated selected grassland sites being comparable with respect to soil type and climatic conditions, which have been continuously treated for many years as intensely used meadows (IM), intensely used mown pastures (IP) and extensively used pastures (EP), respectively. The obtained data were linked to above ground biodiversity pattern as well as water extractable fractions of nitrogen and carbon in soil. Shifts in land use intensity changed plant community composition from systems dominated by s-strategists in extensive managed grasslands to c-strategist dominated communities in intensive managed grasslands. Along the different types of land use intensity, the availability of inorganic nitrogen regulated the abundance of bacterial and archaeal ammonia oxidizers. In contrast, the amount of dissolved organic nitrogen determined the abundance of denitrifiers (nirS and nirK). The high abundance of nifH carrying bacteria at intensive managed sites gave evidence that the amounts of substrates as energy source outcompete the high availability of inorganic nitrogen in these sites. Overall, we revealed that abundance and function of microorganisms involved in key processes of inorganic N cycling (nitrification, denitrification and N fixation) might be independently regulated by different abiotic and biotic factors in response to land use intensity.

Phosphate release kinetics in calcareous grassland and forest soils in response to H+ addition

Phosphate release kinetics in soils are of global interest because sustainable plant nutrition with phosphate will be a major concern in the future. Dissolution of phosphate-containing minerals induced by a changing rhizosphere equilibrium through proton input is one important mechanism that releases phosphate into bioavailable forms. Our objectives were (i) to determine phosphate release kinetics during H+ addition in calcareous soils of the Schwäbische Alb, Germany, and to assess the influence of (ii) land-use type (grassland vs. forest) and (iii) management intensity on reactive phosphate pools and phosphate release rate constants during H+ addition. Phosphate release kinetics were characterized by a large fast-reacting phosphatepool, which could be attributed to poorly-crystalline calcium phosphates, and a small slow-reacting phosphate pool probably originating from carbonate-bearing hydroxylapatite. Both reactive phosphate pools—as well as total phosphate concentrations (TP) in soil—were greater in grassland than in forest soils. In organically fertilized grassland soils, concentrations of released phosphate were higher than in unfertilized soils, likely because organic fertilizers contain poorly-crystalline phosphate compounds which are further converted into sparingly soluble phosphate forms. Because of an enriched slow-reacting phosphate pool, mown pastures were characterized by a more continuous slow phosphate release reaction in contrast to clear biphasic phosphate release patterns in meadows. Consequently, managing phosphate release kinetics via management measures is a valuable tool to evaluate longer-term P availability in soil in the context of finite rock phosphate reserves on earth.

A model-data comparison of Holocene timberline changes in the Swiss Alps reveals past and future drivers of mountain forest dynamics

Mountain vegetation is strongly affected by temperature and is expected to shift upwards with climate change. Dynamic vegetation models are often used to assess the impact of climate on vegetation and model output can be compared with paleobotanical data as a reality check. Recent paleoecological studies have revealed regional variation in the upward shift of timberlines in the Northern and Central European Alps in response to rapid warming at the Younger Dryas/Preboreal transition ca. 11700years ago, probably caused by a climatic gradient across the Alps. This contrasts with previous studies that successfully simulated the early Holocene afforestation in the (warmer) Central Alps with a chironomid-inferred temperature reconstruction from the (colder) Northern Alps. We use LandClim, a dynamic landscape vegetation model to simulate mountain forests under different temperature, soil and precipitation scenarios around Iffigsee (2065m a.s.l.) a lake in the Northwestern Swiss Alps, and compare the model output with the paleobotanical records. The model clearly overestimates the upward shift of timberline in a climate scenario that applies chironomid-inferred July-temperature anomalies to all months. However, forest establishment at 9800 cal. BP at Iffigsee is successfully simulated with lower moisture availability and monthly temperatures corrected for stronger seasonality during the early Holocene. The model-data comparison reveals a contraction in the realized niche of Abies alba due to the prominent role of anthropogenic disturbance after ca. 5000 cal. BP, which has important implications for species distribution models (SDMs) that rely on equilibrium with climate and niche stability. Under future climate projections, LandClim indicates a rapid upward shift of mountain vegetation belts by ca. 500m and treeline positions of ca. 2500m a.s.l. by the end of this century. Resulting biodiversity losses in the alpine vegetation belt might be mitigated with low-impact pastoralism to preserve species-rich alpine meadows.

New results and new ice-borne finds from high-alpine passes in the Bernese Alps (Switzerland)

Archaeological finds from Schnidejoch (2756 m a.s.l.) and Lötschenpass (2690 m a.s.l.) cover the periods from the Early Neolithic to the Middle Ages (4800 BC - 1000 AD). The numerous finds from Schnidejoch discovered since 2003 can now be seen in relationship with Neolithic and Bronze Age settlements in the Rhone valley and together with the early use of alpine meadows and early transhumance. Finds of Early Bronze Age bows from Lötschenpass go back to the 1930ies. New finds of wooden objects and objects made from birch bark melted out from the ice in the summer of 2011. The lecture presents these new finds and an actualized view of Schnidejoch finds.