Traditional Water Meadows: A Sustainable Management Type for the Future?

Traditional meadow irrigation techniques were once widespread throughout Europe and served as a method of grassland intensification before the era of mineral fertilization. Close to Landau (Palatinate), Germany, there are several hectares of traditionally irrigated water meadows that are irrigated twice a year in parts since the medieval age or irrigation has been reinitiated since the 1990. In a research project “WasserWiesenWerte”, we analyzed the ecological and socio-economic value of meadow irrigation. We compared extensively to semi-intensively used meadows with fertilizer application between 0 and 80 kg N/ha per year which were either irrigated or nonirrigated. The results were very motivating. Biomass production is increased by about one-third with irrigation. At the same time, several species groups did not decrease in frequency and diversity in the meadows under irrigation. In contrast, some especially rare species seemed to even profit. Ditch structures turned out to be especially important refuges for sensible meadow species and added a large quantity of additional species to the landscape diversity. We propose that the revitalization of traditional irrigation techniques should be considered when extensively managed grassland—especially hay meadows—are prone to either intensification or abandonment

Historical Irrigated Meadows at the River Queich, Rhineland-Palatinate

For centuries the meadows at the river Queich in southern Rhineland-Palatinate were irrigated to enhance the quantity and quality of hay. With the introduction of fertili-zers irrigation was stopped in most areas but partly reactivated within the last few years. Today we find a small-scaled mosaic of (non-) irrigated and (un-) fertilized meadows. The Institute for Environmental Sciences Landau at the University of Koblenz - Landau conducts interdisciplinary research on the meadows to investigate the effects of irrigation and the interactions between the involved terrestrial and aquatic systems

Local adaptations to frost in marginal and central populations of the dominant forest tree Fagus sylvatica L. as affected by temperature and extreme drought in common garden experiments

Local adaptations to environmental conditions are of high ecological importance as they determine distribution ranges and likely affect species responses to climate change. Increased environmental stress (warming, extreme drought) due to climate change in combination with decreased genetic mixing due to isolation may lead to stronger local adaptations of geographically marginal than central populations. We experimentally observed local adaptations of three marginal and four central populations of Fagus sylvaticaL., the dominant native forest tree, to frost over winter and in spring (late frost). We determined frost hardiness of buds and roots by the relative electrolyte leakage in two common garden experiments. The experiment at the cold site included a continuous warming treatment; the experiment at the warm site included a preceding summer drought manipulation. In both experiments, we found evidence for local adaptation to frost, with stronger signs of local adaptation in marginal populations. Winter frost killed many of the potted individuals at the cold site, with higher survival in the warming treatment and in those populations originating from colder environments. However, we found no difference in winter frost tolerance of buds among populations, implying that bud survival was not the main cue for mortality. Bud late frost tolerance in April differed between populations at the warm site, mainly because of phenological differences in bud break. Increased spring frost tolerance of plants which had experienced drought stress in the preceding summer could also be explained by shifts in phenology. Stronger local adaptations to climate in geographically marginal than central populations imply the potential for adaptation to climate at range edges. In times of climate change, however, it needs to be tested whether locally adapted populations at range margins can successfully adapt further to changing conditions

Invasion of a Legume Ecosystem Engineer in a Cold Biome Alters Plant Biodiversity

Plant ecosystem engineers are widely used to combat land degradation. However, the ability of those plants to modulate limiting abiotic and biotic resources of other species can cause damage to ecosystems in which they become invasive. Here, we use Lupinus nootkatensis as example to estimate and project the hazardous potential of nitrogen fixing herbaceous plants in a sub-polar oceanic climate. L. nootkatensis was introduced to Iceland in the 1940s to address erosion problems and foster reforestation, but subsequently became a high-latitude invader. In a local field survey, we quantified the impact of L. nootkatensis invasion at three different cover levels (0, 10–50, and 51–100%) upon native plant diversity, richness, and community composition of heath-, wood-, and grasslands using a pairwise comparison design and comparisons of means. Afterward, we scaled impacts up to the ecosystem and landscape level by relating occurrences of L. nootkatensis to environmental and human-mediated variables across Iceland using a species distribution model. Plant diversity was significantly deteriorated under high lupine cover levels of the heath- and woodland, but not in the grassland. Plant species richness of the most diverse habitat, the heathland, linearly decreased with lupine cover level. The abundance of small rosettes, cushion plants, orchids, and small woody long-lived plants of the heath declined with invader presence, while the abundance of late successional species and widespread nitrophilous ruderals in wood- and grasslands increased. Distribution modeling revealed 13.3% of Iceland’s land surface area to be suitable lupine habitat. Until 2061–2080, this area will more than double and expand significantly into the Central Highlands due to human mediation and increasingly favorable climatic conditions. Species-rich habitats showed a loss of plant species diversity and richness as well as a change in community composition even in low lupine cover classes. The future increase of suitable lupine habitat might lead to the displacement of cold-adapted native plant species and will certainly challenge conservation as well as restoration of ecosystems in the cold climate of Iceland, but also elsewhere. Lupine invasion speeds up succession, which may be additive with climate change effects, and accelerates ecological change in cold biomes

Lack of hard-seeded species in pre-fire and post-fire seed banks in the region of Murcia (south-eastern Spain)

Permanent seed banks are thought to be of essential importance for the reproductive success of many obligate seeder species during early post-fire succession. To evaluate the role of seed banks for post-fire regeneration in SE Spain, seed bank analyses were carried out on recently burnt sites and in long-unburnt areas in two climatically different regions of the province of Murcia, using the seedling emergence method as well as the physical separation technique. We found great variability in the number of seeds between sites and expositions. Lowest seed numbers were found in the mountains while locally very dense seed banks of > 3500 seeds/m2 in the upper two cm of soil were present at the coast. Species of Poaceae, Asteraceae as well as annual species such as Asterolinum linum- tellatum prevailed whereas hard-seeded species known to occur frequently in post-fire Mediterranean vegetation (e.g. Cistaceae, Fabaceae or Convolvulaceae) were sparse or absent in the seed bank. We conclude that the hard-seeded species are not a self-evident compound of the species composition during post-fire succession of long-unburnt sites in south-eastern Spain

Flower strip networks offer promising long term effects on pollinator species richness in intensively cultivated agricultural areas

Abstract Background Intensively cultivated agricultural landscapes often suffer from substantial pollinator losses, which may be leading to decreasing pollination services for crops and wild flowering plants. Conservation measures that are easy to implement and accepted by farmers are needed to halt a further loss of pollinators in large areas under intensive agricultural management. Here we report the results of a replicated long-term study involving networks of mostly perennial flower strips covering 10% of a conventionally managed agricultural landscape in southwestern Germany. Results We demonstrate the considerable success of these measures for wild bee and butterfly species richness over an observation period of 5 years. Overall species richness of bees and butterflies but also the numbers of specialist bee species clearly increased in the ecological enhancement areas as compared to the control areas without ecological enhancement measures. A three to five-fold increase in species richness was found after more than 2 years of enhancement of the areas with flower strips. Oligolectic bee species increased significantly only after the third year. Conclusions In our long-term field experiment we used a large variety of seed mixtures and temporal variation in seeding time, ensured continuity of the flower-strips by using perennial seed mixtures and distributed the measures over c. 10% of the landscape. This led to an increase in pollinator abundance, suggesting that these measures may be instrumental for the successful support of pollinators. These measures may ensure the availability of a network of diverse habitats and foraging resources for pollinators throughout the year, as well as nesting sites for many species. The measures are applied in-field and are suitable for application in areas under intensive agriculture. We propose that flower strip networks should be implemented much more in the upcoming CAP (common agricultural policy) reform in the European Union and promoted more by advisory services for farmers

High plasticity in germination and establishment success in the dominant forest tree Fagus sylvatica

Abstract Aim Distribution ranges of temperate tree species are shifting poleward and upslope into cooler environments due to global warming. Successful regeneration is crucial for population persistence and range expansion. Thus, we aimed to identify environmental variables that affect germination and seedling establishment of Europe's dominant forest tree, to compare the importance of plasticity and genetic variation for regeneration, and to evaluate the regeneration potential at and beyond the southern and northern distribution margins. Location Europe. Time period 2016–2018. Major taxa studied European beech (Fagus sylvatica (L.)). Methods We investigated how germination, establishment and juvenile survival change across a reciprocal transplantation experiment using over 9,000 seeds of beech from 7 populations from its southern to its northern distribution range margins. Results Germination and establishment at the seedling stage were highly plastic in response to environmental conditions. Germination success increased with warmer and declined with colder air temperature, whereas establishment and survival were hampered under warmer and drier conditions. Germination differed among populations and was positively influenced by seed weight. However, there was no evidence of local adaptation in any trait. Main conclusions The high plasticity in the early life‐history traits found irrespective of seed origin may allow for short‐term acclimatization. However, our results also indicate that this plasticity might not be sufficient to ensure the regeneration of beech in the future due to the low survival found under dry and hot conditions. The future climatic conditions in parts of the distribution centre and at the rear edge might thus become limiting for natural regeneration, as the likelihood of extreme heat and drought events will increase. By contrast, at the cold distribution margin, the high plasticity in the early life‐history traits may allow for increasing germination success with increasing temperatures and may thus facilitate natural regeneration in the future

High plasticity in germination and establishment success in the dominant forest tree Fagus sylvatica across Europe

Abstract Aim Distribution ranges of temperate tree species are shifting poleward and upslope into cooler environments due to global warming. Successful regeneration is crucial for population persistence and range expansion. Thus, we aimed to identify environmental variables that affect germination and seedling establishment of Europe's dominant forest tree, to compare the importance of plasticity and genetic variation for regeneration, and to evaluate the regeneration potential at and beyond the southern and northern distribution margins. Location Europe. Time period 2016–2018. Major taxa studied European beech (Fagus sylvatica (L.)). Methods We investigated how germination, establishment and juvenile survival change across a reciprocal transplantation experiment using over 9,000 seeds of beech from 7 populations from its southern to its northern distribution range margins. Results Germination and establishment at the seedling stage were highly plastic in response to environmental conditions. Germination success increased with warmer and declined with colder air temperature, whereas establishment and survival were hampered under warmer and drier conditions. Germination differed among populations and was positively influenced by seed weight. However, there was no evidence of local adaptation in any trait. Main conclusions The high plasticity in the early life‐history traits found irrespective of seed origin may allow for short‐term acclimatization. However, our results also indicate that this plasticity might not be sufficient to ensure the regeneration of beech in the future due to the low survival found under dry and hot conditions. The future climatic conditions in parts of the distribution centre and at the rear edge might thus become limiting for natural regeneration, as the likelihood of extreme heat and drought events will increase. By contrast, at the cold distribution margin, the high plasticity in the early life‐history traits may allow for increasing germination success with increasing temperatures and may thus facilitate natural regeneration in the future