Langfristige Rohstoffsicherung in der Supply Chain Biogas: Status Quo und Potenziale vertraglicher Zusammenarbeit

Im Zuge des Ausbaus der Biogaserzeugung steigt die Nachfrage nach landwirtschaftlicher Biomasse. Besonders die vermehrt auf den Biogasmarkt tretenden außerlandwirtschaftlichen Biogasbetreiber stehen vor der Herausforderung, ihren Substratbedarf abzusichern. Eine Analyse der Struktur und Entwicklungen entlang der Supply Chain Biogas verdeutlicht die Notwendigkeit zur vertraglichen Zusammenarbeit als Form der koordinierten Rohstoffbeschaffung. Da Biomasseabnehmer i. d. R. nur über wenige Erfahrungen mit Landwirten als Vertragspartnern verfügen, wurden sowohl deren generelle vertragliche Einstellungen als auch deren spezielle Präferenzen hinsichtlich konkreter Inhalte von Biomasselieferverträgen analysiert. Eine Befragung von 209 landwirtschaftlichen Betriebsleitern gibt über beides Aufschluss. Landwirte beurteilen vertragliche Kooperationen infolge differenzierter Freiheitsund Risikopräferenz unterschiedlich. Vertragslieferanten zeichnen sich durch eine geringe Freiheitspräferenz, hohe Risikoaversion und vertikale Orientierung aus. Hinsichtlich der Vertragsinhalte favorisieren sie überwiegend kurzfristige Verträge mit marktorientierter Preisanpassung. Für potenzielle Biomasseerzeuger sind neben einem hohen Preisniveau ferner die landwirtschaftliche und regionale Orientierung des Abnehmers bei Vertragsüberlegungen relevant. Es werden sowohl theoretische Implikationen als auch Empfehlungen hinsichtlich der Akquise von Biomasselieferanten und der Ausgestaltung von Vertragsangeboten gegeben

Beyond the closed-forest paradigm: Cross-scale vegetation structure in temperate Europe before the late-Quaternary megafauna extinctions

The Last Interglacial (∼129,000–116,000 years ago) provides key insights into temperate European vegetation dynamics before significant anthropogenic impacts. Using LOVE (Local Vegetation Estimates) and REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) models, this study reconstructs vegetation patterns across local (∼9 km²) and regional (∼100 km²) scales. Local landscapes presented a heterogeneous mosaic, with averages of 17 % open vegetation, 21 % closed forests, and 63 % light woodlands, reflecting high fine-scale heterogeneity. Importantly, weak local-regional correlations highlight the importance of localised drivers. Longitude and, to a lesser extent, precipitation explained some variation in local vegetation openness, but heterogeneity remained unexplained, emphasising the role of disturbance regimes. Shannon diversity and evenness varied widely, indicating a mix of species-rich and more uniform habitats and reflecting diverse ecological dynamics. Beta diversity showed high spatial turnover, suggesting composition was shaped by localised factors rather than uniform climatic drivers. Frequently represented genera, such as Artemisia, Helianthemum, Erica, Filipendula, and Plantago, indicate diverse open and semi-open habitats, shaped by disturbances and hydrological variability. Weak climatic correlations and dominance of disturbance-adapted taxa suggest active disturbance-shaped vegetation. Large herbivorous mammals (megafauna) likely maintained vegetation openness through grazing and browsing; there is limited evidence for frequent fire activities in this period. These findings challenge the closed forest paradigm for interglacials, revealing substantial openness and heterogeneity. This scale-explicit evidence of Last Interglacial vegetation complexity offers insights into the biodiversity and ecological functionality of pre-anthropogenic ecosystems, with implications for modern conservation and rewilding, particularly in maintaining diversity through disturbance and megafaunal interactions

Terrestrial biosphere changes over the last 120 kyr

A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and used with simulations from the HadCM3 and FAMOUS climate models and the BIOME4 vegetation model to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Simulated biome distributions using BIOME4 driven by HadCM3 and FAMOUS at the global scale over time generally agree well with those inferred from pollen data. Global average areas of grassland and dry shrubland, desert, and tundra biomes show large-scale increases during the Last Glacial Maximum, between ca. 64 and 74 ka BP and cool substages of Marine Isotope Stage 5, at the expense of the tropical forest, warm-temperate forest, and temperate forest biomes. These changes are reflected in BIOME4 simulations of global net primary productivity, showing good agreement between the two models. Such changes are likely to affect terrestrial carbon storage, which in turn influences the stable carbon isotopic composition of seawater as terrestrial carbon is depleted in 13C

Modelling silicon supply during the Last Interglacial (MIS 5e) at Lake Baikal

Limnological reconstructions of primary productivity have demonstrated its response over Quaternary timescales to drivers such as climate change, landscape evolution and lake ontogeny. In particular, sediments from Lake Baikal, Siberia, provide a valuable uninterrupted and continuous sequence of biogenic silica (BSi) records, which document orbital and sub-orbital frequencies of regional climate change. We here extend these records via the application of stable isotope analysis of silica in diatom opal (δ30Sidiatom) from sediments covering the Last Interglacial cycle (Marine Isotope Stage [MIS] 5e; c. 130 to 115 ka BP) as a means to test the hypothesis that it was more productive than the Holocene. δ30Sidiatom data for the Last Interglacial range between +1.29 to +1.78‰, with highest values between c. 127 to 124 ka BP (+1.57 to +1.78‰). Results show that diatom dissolved silicon (DSi) utilisation, was significantly higher (p=0.001) during MIS 5e than the current interglacial, which reflects increased diatom productivity over this time (concomitant with high diatom biovolume accumulation rates [BVAR] and warmer pollen-inferred vegetation reconstructions). Diatom BVAR are used, in tandem with δ30Sidiatom data, to model DSi supply to Lake Baikal surface waters, which shows that highest delivery was between c. 123 to 120 ka BP (reaching peak supply at c. 120 ka BP). When constrained by sedimentary mineralogical archives of catchment weathering indices (e.g. the Hydrolysis Index), data highlight the small degree of weathering intensity and therefore representation that catchment-weathering DSi sources had, over the duration of MIS 5e. Changes to DSi supply are therefore attributed to variations in within-lake conditions (e.g. turbulent mixing) over the period, where periods of both high productivity and modelled-DSi supply (e.g. strong convective mixing) account for the decreasing trend in δ30Sidiatom compositions (after c. 124 ka BP)

Vegetation and climate variability during the Last Interglacial evidenced in the pollen record from Lake Baikal

A high-resolution pollen record from the core sediments collected in the northern part of Lake Baikal represents the latest stage of the Taz (Saale) Glaciation, Kazantsevo (Eemian) Interglacial (namely the Last Interglacial), and the earliest stage of the Zyryanka (Weichselian) Glaciation. According to the palaeomagnetic-based age model applied to the core, the Last Interglacial in the Lake Baikal record lasted about 10.6 kyrs from 128 kyr to 117.4 kyr BP, being more or less synchronous with the Marine Isotope Stage 5e. The reconstructed changes in the south Siberian vegetation and climate are following. A major spread of shrub alder (Duschekia fruticosa = Alnus fruticosa) and shrub birches (Betula sect. Nanae/Fruticosae) in the study area was a characteristic feature during the late glacial phase of the Taz Glaciation. Boreal trees e.g. spruce (Picea obovata) and birch (Betula sect. Albae) started to play an important role in the regional vegetation with the onset of the interglacial conditions. Optimal conditions for Abies sibirica-Picea obovata taiga development occurred ca. 126.3 kyr BP. The maximum spread of birch forest-steppe communities took place at the low altitudes ca. 126.5-125.5 kyr BP and Pinus sylvestris started to form forests in the northern Baikal area after ca. 124.4 kyr BP. Re-expansion of the steppe communities, as well as shrubby alder and willow communities and the disappearance of forest vegetation occurred at about 117.4 kyr BP, suggesting the end of the interglacial succession. The changes in the pollen assemblages recorded in the sediments from northern Baikal point to a certain instability of the interglacial climate. Three phases of climate deterioration have been distinguished: 126-125.5, 121.5-120, and 119.5-119 kyr BP. The penultimate cooling signal may be correlated with the cool oscillation recorded in European pollen records. However, such far distant correlation requires more careful investigation

Paléoenvironnement et paléoclimat de l’Oligocène inférieur de la périphérie orientale de la mer du Nord, d’après des études palynologiques à haute résolution du forage Grabówka PIG-1, Nord de la Pologne

Les études palynologiques à haute résolution des strates de l’Oligocène inférieur du forage Grabówka PIG-1 des périphéries orientales de la mer du Nord (golfe polonais) ont révélé la présence de 165 espèces fossiles de sporomorphes (grains de pollen et spores), de nombreux palynomorphes marins (par exemple des kystes de dinoflagellés), des algues d’eaux douces et saumâtres, ainsi que des restes fongiques (y compris des microsclérotes endophytes bruns septés des racines des plantes). La composition de l’assemblage palynologique, comprenant les espèces fossiles Boehlensipollis hohli Krutzsch et Aglaoreidia cyclops Erdtman, confirme l’âge Oligocène inférieur des strates. La présence de nombreux kystes de dinoflagellés tout au long de la succession Grabówka PIG-1 indique clairement son dépôt dans un environnement marin peu profond, proche du rivage. Les résultats de l’analyse sporo-­pollinique indiquent la présence d’une végétation luxuriante avec de nombreux éléments thermophiles (y compris des membres des familles pantropicales Meliaceae Jussieu et Sapotaceae Jussieu ainsi que les familles subtropicales-tropicales Arecaceae Berchtold &amp; J.Presl, Schizaeaceae Kaulfman, Cyatheaceae Kaulfman et/ou Gleicheniaceae C.Presl) dans les terres voisines. Les forêts mésophytiques mixtes, les forêts de zones humides (marécageuses ou riveraines), les tourbières arbustives et la végétation d’eau douce/marais dominaient. Le climat était subtropical et humide. L’ensemble de la succession palynologique correspond à la 5e couche de lignite de Czempiń, corrélée à la 5e couche de Lusace dans le Sud-Est de l’Allemagne, qui constitue un horizon de corrélation important pour l’Oligocène inférieur en Europe centrale. Les résultats fournissent de nouvelles informations sur la végétation et les changements paléoclimatiques des latitudes moyennes au cours de la transition « greenhouse/icehouse » de l’Oligocène inférieur.High-resolution palynological studies of the lower Oligocene strata from the Grabówka PIG-1 borehole from the eastern peripheries of the North Sea (Polish Gulf) revealed the presence of 165 fossil-species of sporomorphs (pollen grains and spores), numerous marine palynomorphs (e.g. dinoflagellate cysts), freshwater and brackish algae, plus fungal remains (including microsclerotia of dark septate endophytes inhabiting roots of plants). The composition of the palynological assemblage, including the fossil-species Boehlensipollis hohli Krutzsch and Aglaoreidia cyclops Erdtman, confirms the early Oligocene age of the strata. The presence of numerous dinoflagellate cysts throughout the Grabówka PIG-1 succession clearly indicates its deposition in a shallow marine, near-shore environment. The results of the spore-pollen analysis indicate the presence of lush vegetation with numerous thermophilous elements (including members of the pantropical families Meliaceae Jussieu and Sapotaceae Jussieu as well as the subtropical-tropical families Arecaceae Berchtold &amp; J.Presl, Schizaeaceae Kaulfman, ­Cyatheaceae Kaulfman and/or Gleicheniaceae C.Presl) in the neighbouring land area. Mixed mesophytic forests, wetland (swamp or riparian) forests, shrub bogs, and freshwater/marsh vegetation dominated there. The climate was subtropical and humid. The entire palynological succession corresponds to the 5th Czempiń group of lignite seams, correlated with the 5th Lusatian seam in south-eastern Germany, which is an important correlation horizon for the lower Oligocene in Central Europe. The results provide new insights into the vegetation and palaeoclimate changes in mid-latitudes during the early Oligocene greenhouse/icehouse transition.</p

Farmers' decision behaviour regarding investments in biogas production

Farmers' decision behaviour regarding investments in biogas production Among the renewable energies, biogas production has expanded greatly in the German agricultural sector in the last few years. For farmers, the improved financial incentives and legal framework give rise to attractive investment opportunities. To estimate more accurately farmers' willingness to invest, the decision-making process is crucial. This paper examines the factors which determine farmers' decision behaviour regarding investments in biogas production. Based on a survey the results have shown that the social environment and the perceived intensity of competition between farmers are most relevant for their investment decision. The most important conclusion relates to the forecast of future expansion potential of agricultural biogas production. This would need to be extended to include social patterns of farmers' investment confidence in order to be able to make reliable predictions