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Learned vocal signals of birds provide one of the most comprehensive sources of evidence for culture in animals. Such vocal signals often vary spatially and temporally. Signal variation can be driven by direct factors such as cultural drift and selection or by indirect factors such as changes in the environment, which may affect morphology and therefore acoustic capability. In this study we analysed flight and excitement calls of several call types of the Red Crossbill Loxia curvirostra and other crossbill species. Calls were recorded between 1962 and 2019 across the Palaearctic region. We measured acoustic similarity within flight and excitement calls and modelled the size of the effect attributed to temporal and geographical distance. Geographical distance between different sampling locations explained less call variation compared with temporal distance, and temporal variation within the excitement calls was smaller than in the flight calls. We conclude that calls of most call types of Red, Scottish and Parrot Crossbill are an example of cultural evolution. We suggest that excitement calls are less modifiable because they can serve better in dangerous situations when they are stable in time and space. In addition, we found no clear support for increasing or decreasing flight call similarity of call types while or after being in contact, as found in another study from North America. The reasons for the cultural evolution in calls of Palaearctic crossbills remain unclear. [ABSTRACT FROM AUTHOR]

Restoration of degraded peatland ecosystems (by rewetting) is undertaken to bring back key ecosystem services. However, the restoration process can have a range of ecohydrological effects, due to the associated physical and biogeochemical disturbance. In the case of northern peatlands drained by large and deep ditches, the rewetting effects are relatively unknown. The raised bog Grande plée Bleue (1,500 ha) is one of the largest pristine bogs in the St‐Lawrence lowlands in North America; however, it contained an old (>60 years), 750 m long, 3.5 m deep, and 8 m wide ditch. Rewetting of the area affected by the ditch was carried out by the construction of six dams at 40 cm elevation intervals and felling of all trees (with diameter at breast height >10 cm) within 30 m. Water table was restored to levels similar to intact bog reference sites, only at elevation differences up to 17 cm from the nearest lower dam, while rewetting did not affect pore‐water chemistry. Five to 6 years post‐rewetting, the cover of both pioneer mosses, and late successional mosses (Sphagnum) had not changed significantly compared with pre‐rewetting. This may have been due to the presence of dense shrub cover. For more effective ecohydrological restoration, dams should be spaced at smaller elevation intervals (e.g., every 20 cm of elevation or less), to allow recovery of water table along the entire length of the ditch, and vegetation introduction using the moss layer transfer technique may accelerate Sphagnum recruitment, especially in the few first metres from the ditch. [ABSTRACT FROM AUTHOR]

Peatland restoration in North America ( NA) was initiated approximately 25 years ago on peat-extracted bogs. Recent advances in peatland restoration in NA have expanded the original concepts and methodology. Restoration efforts in NA now include restoring peatlands from many diverse types of disturbances (e.g. roads, agriculture, grazing, erosion, forestry, and petrol industry infrastructure impacts) and occur in a greater array of peatland types (e.g. fens and swamps). Because fens are groundwater and surface flow driven, techniques to restore the hydrology of fens are generally more complicated than bogs. Restoring a greater variety of peatland types on a large-scale basis (>10 ha) commands new techniques for reestablishing a broader array of plants other than Sphagnum spp., including non- Sphagnum mosses, sedges, nonericaceous shrubs, and trees. The rationale for restoring peatlands has expanded to include legal requirements, wetland mitigation and banking, climate mitigation, water quality, and as part of responsible ecosystem management for industry or society. In the past 25 years, peatland restoration in NA has evolved from (1) trial and error to a more empirically based scientific approach, (2) small site-specific experiments to landscape-scale restoration (e.g. hydrological connectivity, ecological fragmentation), and (3) individual stakeholder (academic) to multiple stakeholders across jurisdictional boundaries (private, local, and regional governmental agencies, NGOs, and so on). However, many research gaps still exist that must be addressed to enhance our ability to restore peatlands successfully. [ABSTRACT FROM AUTHOR]

Ecological gradients have always been a central theme of plant ecology. Yet, very little is known on the bog-lagg-mineral land gradient. Improved knowledge of this gradient is important to the understanding of wetland plant ecology and wetland delineation alike. In this study, the relation between vegetation composition and peat thickness is analysed in 20 raised bogs of eastern Canada using split moving window dissimilarity analysis. Four different transition types are identified: (1) an abrupt transition without an ecotonal community; (2) a narrow transition with a lagg-swamp ecotonal community (most common transition type); (3) a narrow transition with two ecotonal communities (a lagg-fen and a lagg-swamp); and (4) a broad transition with a large wetland adjacent to the bog. Laggs that could be defined as separate habitat (type 1) occured, on average, on peat soil over 30 cm thick (defined as > 30 % dry mass of organic matter), making the lagg an integral part of the peatland complex. Other unique features of the lagg are: (1) a very densely structured habitat where trees, shrubs, herbs and Sphagnum mosses are abundant; (2) soils characterised by relatively high contents of total nitrogen and total phosphorus, but a particularly low N:P ratio (8.7 ± 2.5); and (3) a relatively high water table, which fluctuates substantially (from −33 to +10 cm in site A; from −12 to +10 in site B). [ABSTRACT FROM AUTHOR]

ABSTRACT Fens represent a large array of ecosystem services, including the highest biodiversity found among wetlands, hydrological services, water purification and carbon sequestration. Land-use change and drainage has severely damaged or annihilated these services in many parts of North America and Europe; restoration plans are urgently needed at the landscape level. We review the major constraints on the restoration of rich fens and fen water bodies in agricultural areas in Europe and disturbed landscapes in North America: ( i) habitat quality problems: drought, eutrophication, acidification, and toxicity, and ( ii) recolonization problems: species pools, ecosystem fragmentation and connectivity, genetic variability, and invasive species; and here provide possible solutions. We discuss both positive and negative consequences of restoration measures, and their causes. The restoration of wetland ecosystem functioning and services has, for a long time, been based on a trial-and-error approach. By presenting research and practice on the restoration of rich fen ecosystems within agricultural areas, we demonstrate the importance of biogeochemical and ecological knowledge at different spatial scales for the management and restoration of biodiversity, water quality, carbon sequestration and other ecosystem services, especially in a changing climate. We define target processes that enable scientists, nature managers, water managers and policy makers to choose between different measures and to predict restoration prospects for different types of deteriorated fens and their starting conditions. [ABSTRACT FROM AUTHOR]

Fen bryophytes are an important component of natural fens and should be included in fen restoration projects. The goal of this study was to examine the regeneration capabilities of nine bryophytes common to moderate-rich and poor fens in North America. A greenhouse experiment was carried out to examine the limitations and optima for the regeneration of fen bryophytes under different light and water regimes. A field experiment tested these same bryophytes in the presence of three potential nurse-plants. In the greenhouse experiment, the presence of shade increased regeneration success for eight out of nine species. A high water level was ideal for the regeneration of the majority of species tested. In the field experiment, Sphagnum species had the highest regeneration, and all species had higher regeneration under a dense canopy of herbaceous plants. Fen bryophytes show good potential for use in restoration projects because the tested bryophytes regenerated well from fragments. [ABSTRACT FROM AUTHOR]

Cloudberry (Rubus chamaemorus L.) cultivation is receiving increasing attention as a means of revitalising regional economy and rehabilitating cutover peatlands. The study reported here investigated the necessary soil physical and hydrological conditions, the compatibility of cloudberry cultivation with restoration of mined peatlands, and the performance of newly commercialised Norwegian cultivars in North America. Terraces at two levels were landscaped in peatland after vacuum extraction of peat to create different growing conditions in terms of hydrology and soil properties, then planted with two Norwegian cultivars (Fjordgull and Fjellgull) and two local (east Canadian) clones of cloudberry in a randomised block experiment. After three years, both the clones and the cultivars grown on the lower terrace had more leaves per m² due to lower soil bulk density combined with higher average water level. Mulching, inherent to restoration, reduced the number of leaves produced during the year following planting. The Fjordgull cultivar had a higher survival rate than Fjellgull and local clones. Overall, the number of living rhizomes decreased over the years following planting. These results suggest that soil properties (bulk density and porosity) significantly influence cloudberry establishment and growth. Rhizomes should be planted two or three years after peatland restoration to avoid the initial negative effects of the mulch. [ABSTRACT FROM AUTHOR]

Question: Which restoration measures (reintroduction techniques, reintroduction timing and fertilization) best enable the establishment of fen species on North American cut-away peatlands? Location: Rivière-du-Loup peatland, southern Québec, Canada. Methods: In total, eight treatments which tested a combination of two reintroduction techniques, two reintroduction timings and the use of phosphorus fertilization were tested in a field experiment within a completely randomized block design. Results: Sphagnum transfer, a reintroduction technique commonly used for bog restoration in North America, was effective for establishing Sphagnum and Carex species. The hay transfer method, commonly used for fen restoration in Europe, was much less successful, probably due to questionable viability of reintroduced seeds. The treatments which included light phosphorus fertilization, had a higher Carex cover after three growing seasons. The timing of the reintroductions had no impact on the success of vegetation establishment. However, vegetation reintroduction should be carried out in the spring while the ground is still frozen to minimize other ecological impacts. Conclusions: The success of the diaspore reintroduction technique on small-scale units indicates that a large-scale restoration of fens using this technique is feasible. [ABSTRACT FROM AUTHOR]

Sphagnum dominated peatlands do not rehabilitate well after being cutover (mined) for peat and some action needs to be taken in order to restore these sites within a human generation. Peatland restoration is recent and has seen significant advances in the 1990s. A new approach addressing the North American context has been developed and is presented in this paper. The short-term goal of this approach is to establish a plant cover composed of peat bog species and to restore a water regime characteristic of peatland ecosystems. The long-term objective is to return the cutover areas to functional peat accumulating ecosystems. The approach developed for peatland restoration in North America involves the following steps: 1) field preparation, 2) diaspore collection, 3) diaspore introduction, 4) diaspore protection, and 5) fertilization. Field preparation aims at providing suitable hydrological conditions for diaspores through creation of microtopography and water retention basins, re-shaping cutover fields and blocking ditches. It is site specific because it depends largely on local conditions. The second step is the collection of the top 10 centimetres of the living vegetation in a natural bog as a source of diaspores. It is recommended to use a ratio of surface collected to surface restored between 1: 10 and 1: 15 in order to minimize the impact on natural bogs and to insure rapid plant establishment in less than four years. Diaspores are then spread as a thin layer on the bare peat surfaces to be restored. It has been demonstrated that too scant or too thick a layer decreases plant establishment success. Diaspores are then covered by a straw mulch applied at a rate of 3 000 kg ha-1 which provides improved water availability and temperature conditions. Finally, phosphorus fertilization favours more rapid substrate colonization by vascular plants, which have been shown to help stabilize the bare peat surface and act as nurse plants to the Sphagnum mosses. [ABSTRACT FROM AUTHOR]