The effect of accidental burning on habitat conditions and species composition of Molinion caeruleae meadows

This study aimed to assess the effects of accidental burning on plant cover and habitat conditions in abandoned Molinion caeruleae meadows. Field studies were conducted in Kraków (Southern Poland) in the years 2017–2019 in two line transects, each with 10 permanent plots established in permanent study plots placed in accidentally burned and unburned patches. In the burned patch, the number of species, as well as Shannon-Wiener, Pielou and Simpson indicators achieved lower values. Moreover, the cover of numerous taxa affiliated with Molinion caeruleae changed remarkably, while taxa representing the alliances Calthion and Filipendulion disappeared. The considerable dominance of hemicryptophytes was observed in burned site, while in unburned place hemicryptophytes and geophytes were represented most abundantly. In the burned patch, anemochorous and autochorous species as well as small-seeded taxa dominated, while in the unburned patch autochorous species and medium-seeded taxa prevailed. The values of Ellenberg indicators in the burned patch achieved greater (light, soil reaction), lower (nitrogen, humidity) or similar (temperature, continentality) values to the unburned patch. The majority of soil properties in the burned and unburned patches were similar with the exception of the significantly greater content of potassium and lower content of magnesium in exchangeable form noticed in the burned patch. The performed investigations showed that, although the accidental fire activity inhibited the secondary succession in Molinion caeruleae meadows, burning cannot replace traditional mowing due to the reduction of species richness and disappearance of characteristic taxa.     

Ecology of spring-migrating Anatidae: a review

Spring migration is generally considered as a crucial period of the year for many birds, not the least due to its supposed importance for subsequent breeding success. By reviewing the existing literature for Anatidae (ducks, geese, and swans), we show that little is known about their ecology in spring, although some goose species are exceptions. Another general pattern is that the ecology of Anatidae at staging sites is particularly neglected. Existing studies tend to focus on questions dealing with acquisition of nutrient reserves, whereas almost nothing has been published about stopover habitats, time use, microhabitat use, foraging behaviour, food availability, food limitation, diet selection, and interspecific relationships. Besides summarising present knowledge, we identify taxonomic groups and topics for which gaps of knowledge appear the most evident, thereby also highlighting research needs for the future.     

Distinctive invertebrate assemblages in rockface seepages enhance lotic biodiversity in northern New Zealand

We measured water quality, recorded physical habitat characteristics and collected aquatic invertebrates from 17 rockface seeps, five springs and five streams in a geologically diverse region of New Zealand's North Island to investigate factors influencing invertebrate distribution and community composition within and among these habitats. A total of 147 aquatic invertebrate taxa was found; 84 taxa occurred in seepage samples and 53% of these were found only in those habitats, including several new species. Where paired stream-seepage comparisons could be made, seeps contributed on average 35% of new species to the total species pool. The invertebrate faunas of all habitats were dominated taxonomically by Trichoptera and Diptera, but seepages were relatively depauperate in Ephemeroptera and richer in Coleoptera taxa compared to streams and springs. Seepage faunas were dominated numerically by Mollusca, and had lower percent abundance of aquatic insects (23% overall) compared to springs (77%) and streams (93%). Seepages underlain by different geologies generally had distinct water quality signatures, with seeps draining greywacke, sandstone and volcanic rocks grouping close to their receiving streams in a Principal Component Analysis. Seepage invertebrate community composition reflected underlying geology and associated differences in water chemistry, as well as seepage size and cover by moss. Incorporation of seepage habitats into conservation planning and aquatic ecosystem protection, and maintenance of their function and connectivity with lotic and groundwater ecosystems are important considerations for freshwater biodiversity management. Maintenance of riparian plant cover over seepages should help sustain supplies of organic matter, moss cover and shade, providing habitat complexity and low water temperatures.     

Effectiveness of repeated autumn and spring fires for understorey restoration in weed‐invaded temperate eucalypt woodlands

Question. Can strategic burning, targeting differing ecological characteristics of native and exotic species, facilitate restoration of native understorey in weed‐invaded temperate grassy eucalypt woodlands? Location. Gippsland Plains, eastern Victoria, Australia. Methods. In a replicated, 5‐year experimental trial, the effects of repeated spring or autumn burning were evaluated for native and exotic plants in a representative, degraded Eucalyptus tereticornis grassy woodland. Treatments aimed to reduce seed banks and modify establishment conditions of exotic annual grasses, and to exhaust vegetative reserves of exotic perennial grasses. Treatments were applied to three grassland patch types, dominated by the native grass Austrodanthonia caespitosa, ubiquitous exotic annuals, or the common exotic perennial grass Paspalum dilatatum. Results. The dominant native grass Austrodanthonia caespitosa and native forbs were resilient to repeated fires, and target exotic annuals and perennials were suppressed differentially by autumn and spring fires. Exotic annuals were also suppressed by drought, reducing the overall treatment effects but indicating important opportunities for restoration. The initially sparse exotic geophyte Romulea rosea increased in cover with fire and the impact of this species on native forbs requires further investigation. There was minimal increase in diversity of subsidiary natives with fire, probably owing to lack of propagules. Conclusions. While fire is often considered to increase ecosystem invasibility, our study showed that strategic use of fire, informed by the relative responses of available native and exotic taxa, is potentially an effective step towards restoration of weed‐invaded temperate eucalypt woodlands.     

Interceptions of Nonindigenous Plant Pests at US Ports of Entry and Border Crossings Over a 17-year Period

Despite the substantial impacts of nonindigenous plant pests and weeds, relatively little is known about the pathways by which these organisms arrive in the U.S. One source of such information is the Port Information Network (PIN) database, maintained by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) since 1984. The PIN database is comprised of records of pests intercepted by APHIS personnel during inspections of travelers’ baggage, cargo, conveyances and related items arriving at U.S. ports of entry and border crossings. Each record typically includes the taxonomic identify of the pest, its country of origin, and information related to the commodity and interception site. We summarized more than 725,000 pest interceptions recorded in PIN from 1984 to 2000 to examine origins, interception sites and modes of transport for nonindigenous insects, mites, mollusks, nematodes, plant pathogens and weeds. Roughly 62% of intercepted pests were associated with baggage, 30% were associated with cargo and 7% were associated with plant propagative material. Pest interceptions occurred most commonly at airports (73%), U.S.-Mexico land border crossings (13%) and marine ports (9%). Insects dominated the database, comprising 73 to 84% of the records annually, with the orders Homoptera, Lepidoptera and Diptera collectively accounting for over 75% of the insect records. Plant pathogens, weeds and mollusks accounted for 13, 7 and 1.5% of all pest records, respectively, while mites and nematodes comprised less than 1% of the records. Pests were intercepted from at least 259 different locations. Common origins included Mexico, Central and South American countries, the Caribbean and Asia. Within specific commodity pathways, richness of the pest taxa generally increased linearly with the number of interceptions. Application of PIN data for statistically robust predictions is limited by nonrandom sampling protocols, but the data provide a valuable historical record of the array of nonindigenous organisms transported to the U.S. through international trade and travel.     

抑制剂及其组合对尿素15N在小麦土壤系统中的行为和归宿的影响

应用加有脲酶抑制剂(HQ)、硝化抑制剂(DCD)及其组合的标记尿素进行春小麦盆栽试验.结果表明,在生长季节结束时,小麦回收,土壤残留和损失的肥料N各占施入N量的17.65～23.69%、43.72～56.32%和19.99～36.77%.其中,与单施尿素相比,两种抑制剂配合使用处理的肥料N总回收率高16.78%,小麦回收高5.96%.施用氮肥对籽粒贡献最大,占吸收肥料N量43.3～62.0%.     

Flowering plant phenology and weather in Alberta,Canada

Plant phenology can be used for biomonitoring climate change. The flowering of certain temperate zone plant species occurs in response to accumulated heat. Networks of observers presently provide data on the timing of the growth of native and crop plants to Agro-meteorological Departments in Europe and the United States. In Alberta, a phenological survey which began in 1987 records flowering times for 15 native plants, with about 200 volunteers contributing observations annually. Six years of data have been summarized and correlated with temperature measurements. The Alberta phenological data can provide a key to sound decision-making in two ways: by providing proxy data on key variables to which vegetation responds, and by providing a model for transforming simple weather data into biologically meaningful zones.     

Timing of migration dates and detection of first wintering sites for the Turtle Dove in Northwest Africa

The identification of migration dates and wintering zones for migratory birds are key elements for the understanding of the Afro-Palearctic migration system. From 2015 to 2022, a large-scale survey of Turtle Doves Streptopelia turtur, a vulnerable species, was established in Northwest Africa, including Morocco, Algeria, and Tunisia. We monitored migration dates and wintering individuals using the line-transect method. We found that Turtle Doves arrived in the last week of March and left the North African region in mid-October. Compared with Morocco, Doves arrived significantly earlier in Algeria and Tunisia. Moreover, Doves were discovered wintering on nine Northwest African sites, from October to February, where individuals feed in groups. We found that the occurrence probability of wintering Turtle Doves decreased significantly with increasing temperature and rainfall. Birds wintered most often close to wetlands since the overwintering probability decreased with the increasing distance from the recording area to the nearest water body. These are the first and only detailed findings on the migration phenology of the globally vulnerable Turtle Dove in north western Africa.     

Combining historical agricultural and climate datasets sheds new light on early 20th century barley performance

Barley (Hordeum vulgare ssp. vulgare) is cultivated globally across a wide range of environments, both in highly productive agricultural systems and in subsistence agriculture and provides valuable feedstock for the animal feed and malting industries. However, as the climate changes there is an urgent need to identify adapted barley varieties that will consistently yield highly under increased environmental stresses. Our ability to predict future local climates is only as good as the skill of the climate model, however we can look back over 100 years with much greater certainty. Historical weather datasets are an excellent resource for identifying causes of historical yield variability. In this research we combined recently digitised historical weather data from the early 20th century with published Irish spring barley trials data for two heritage varieties: Archer and Goldthorpe, following an analysis first published by Student in 1923. Using linear mixed models, we show that interannual variation in observed spring barley yields can be partially explained by recorded weather variability, in particular July maximum temperature and rainfall, and August maximum temperature. We find that while Archer largely yields more highly, Goldthorpe is more stable under wetter growing conditions, highlighting the importance of considering growing climate in variety selection. Furthermore, this study demonstrates the benefits of access to historical trials and climatic data and the importance of incorporating climate data in modern day breeding programmes to improve climate resilience of future varieties.     

绿洲生态条件下春小麦蒸发蒸腾特征及其影响因子

 在河西走廊临泽绿洲北部试验区,对春小麦进行3种水分处理并同时观测了全生育期内的蒸发蒸腾(ET)及环境中各生态因子和植物生理指标。结果表明：当年全生育期内,春小麦ET在充分供水条件下为593mm;在中等供水条件下为365mm;在少量供水条件下为280mm。其日蒸散量分别为5.5mm,3.4mm和2.8mm。讨论了影响ET和植物蒸腾的各植物生理指标和环境因子,发现在植物诸指标与蒸腾相关程度的顺序为：叶片水势、气孔导度和叶温(充分供水)及叶片水势、叶温和气孔导度(水分胁迫)。在环境诸因子中与ET的相关程度顺序是：有效光合辐射、净辐射、20cm土温、大气饱和水汽压差,15cm土温、气温、10cm土温、土壤表面温度及5cm土温。