The transmission ecology of Tahyna orthobunyavirus in Austria as revealed by longitudinal mosquito sampling and blood meal analysis in floodplain habitats

Background Tahyna orthobunyavirus (TAHV) is a mosquito-borne virus that may cause mild flu-like symptoms or neurological symptoms in humans. It is historically associated with floodplain habitats in Central Europe, and the mammalophilic floodwater mosquito, Aedes vexans, is thought to be the principal vector. There are few contemporary reports of TAHV transmission ecology within mosquitoes or their vertebrate hosts, and virus infections are rarely reported (and probably seldom diagnosed). The objectives of this study were to survey the mosquito population for TAHV in three floodwater habitats and describe host usage by the predominant floodwater mosquito species to potentially define TAHV transmission at these foci. Methods We performed longitudinal mosquito sampling along three major rivers in eastern Austria to characterize the mosquito community in floodplain habitats, and tested for the presence of TAHV in pools of mosquitoes. We characterized TAHV rescued from mosquito pool homogenate by sequencing. We surveyed mosquito host selection by analyzing mosquito blood meals. Results We identified TAHV in two pools of Ae. vexans captured along the Leitha River. This mosquito, and other floodwater mosquitoes, used large mammals (red deer, roe deer, wild boar) as their hosts. The sequence of the rescued virus was remarkably similar to other TAHV isolates from the region, dating back to the first isolate of TAHV in 1958. Conclusions In general, we confirmed that TAHV is most likely being transmitted by Ae. vexans, although the precise contribution of vertebrate-amplifying hosts to the ecological maintenance of the virus is unclear. The pattern of host selection matches the estimated exposure of the same large mammal species in the region to TAHV based on a recent serosurvey, but hares were also hosts at the site where TAHV was detected. We also confirm humans as hosts of two floodwater mosquito species, providing a potential mechanism for spillover of TAHV or other mosquito-borne viruses. Graphical Abstract

Shift towards Opportunistic Life-History of Sleeper in Response to Population Decline over Multi-Decadal Overfishing

Understanding long-term changes in life-history traits is central to assessing and managing freshwater fisheries. In this study, we explored how life-history traits have shifted in association with long-term change in population status for a native fish species (freshwater sleeper, Odontobutis sinensis, a by-catch species of shrimp traps) in the middle Yangtze lakes, China. We assessed the life-history traits of the species from Honghu Lake in 2016, where abundance had been dramatically lower following about 60 years of high fishing pressure, and made comparisons to similar data from Liangzi Lake (1957), when fishing intensity was low and abundance was high, and Bao’an Lake (1993–1994), when about 10 years of intense exploitation had occurred and abundance had greatly declined. Modern Honghu Lake sleeper exhibit life-history traits that are substantially more opportunistic compared to both of the historical populations. Modern fish were larger at age-1 and had significantly faster growth rates, a higher prevalence of sexually mature individuals and increased fecundities. Fish from the historical samples were larger and had higher age class diversity and delayed sexual maturation. Combined, the data suggest that faster growth towards early sexual maturation and reduced body sizes are associated with destabilized populations and ecosystems. Similar life-history patterns are common in other declined fish populations under exploitation. Recovering historic fish life-history dynamics requires conservation management policies aimed at reducing harvest and improving floodplain habitats.

Crop wild relative materials from field research in the Yakutsk vicinity in 2020

The N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) is working on replenishing seed and herbarium collections of cultivated plants and their wild relatives through collection missions in various regions of Russia. The collections are replenished with both live specimens (plantlets, runners, cuttings, bulbs, seeds, etc.), and with herbarium specimens of crop wild relatives (CWR). The Republic of Sakha (Yakutia) is characterized by a variety of natural conditions and resources, while many territories are difficult to reach by transport. Collection missions were carried out by VIR in the territory of Yakutia from 1972 to 1990. Field research in the territory of the republic is relevant to this day.In 2020, field research in the area of the projected bridge crossing over the Lena River near the city of Yakutsk resulted in collecting 18 samples of wild relatives of fruit, vegetable, essential oil, oil and fiber, forage legume, and cereals crops (live plants and seeds), as well as 45 CWR herbarium specimens. CWR (species of currants, onions, horseradish, water sorrel, tarragon wormwood, etc.) were found in floodplain habitats and on river banks, some were collected in ruderal biotopes, near settlements, less often in forest phytocenoses, and on steppe meadow slopes. All the samples were included in VIR collections. The phytocenoses from which CWR were collected, were comprehensively described.

Temperature dynamics in Klamath River off-channel floodplain restoration sites depend on location within the watershed

The mid-Klamath River is heavily impacted by altered streamflow and warm water temperatures, which contribute to the decline of native salmonids. In an effort to restore critical salmonid habitat, the Karuk Tribe, National Forest Service, and Mid-Klamath Watershed Council have created a variety of off-channel floodplain ponds that provide habitat for juvenile Coho Salmon (Oncorhynchus kisutch) and other juvenile salmonids such as Steelhead (O. mykiss). One purpose of these ponds is to provide cool water refuges for juvenile salmonids during high summer water temperatures. However, no studies have quantified how these ponds vary in temperature regimes across the river floodplain. In July 2020, we placed 30 temperature sensors in 9 off-channel ponds and 2 creeks (Seiad Creek and Horse Creek) in the mid-Klamath floodplain. We used a multivariate auto-regressive state space (MARSS) models to determine the number and spatial arrangement of distinct thermal regimes in floodplain ponds and tributaries. We found that pond temperatures have lower daily maximums and fluctuate less than tributary temperatures. We also found that Seiad Creek, Seiad Creek ponds, Horse Creek, and Horse Creek ponds all have different patterns of temperature change throughout the summer. Historical data (2010-2019) for Alexander and Stender Ponds showed that over time, daily fluctuations in pond water temperature became less drastic. This pattern was also observed by MKWC in their reports on Alexander and Stender Ponds (MKWC 2020; Wickman et al. 2020). More stable water temperatures in the ponds contrast to creek temperatures, which continue to fluctuate widely on a daily basis during summer. Fish monitoring data from MKWC show that coho growth rates are higher in these two ponds, which suggests that coho experience a metabolic benefit from more stable water temperatures (MKWC 2020; Wickman et al. 2020). Overall, our analysis provides deeper insight into the thermal benefits of floodplain habitats and off-channel ponds on the mid-Klamath River, and informs the future collection of fish data that will reveal more precise information about how floodplains benefit salmonids.

Importance of woodland patches as hibernacula for gartersnakes in a prairie river floodplain of central Nebraska

Gartersnakes are common inhabitants along prairie rivers in the Great Plains, but little information is known about hibernacula among diverse floodplain habitats. We radio-tracked Common Gartersnakes (Thamnophis sirtalis) and Plains Gartersnakes (Thamnophis radix) to hibernacula on islands in a braided river system subject to frequent environmental changes along the Platte River in central Nebraska. We further examined capture rates of gartersnakes in floodplain woodland patches from June to November to examine seasonal use of this habitat. In early and mid-September, movements of snakes with transmitters were in grasslands. From late September to mid-October, the farthest movements were documented, and snakes moved from grasslands into woodland patches. From late October to January, movements were minimal in and around hibernacula in wooded or formerly wooded habitats. Capture rates of gartersnakes in woodland trapping arrays also increased in October and November, further demonstrating woodland use during times when snakes travel to and reside at hibernacula. Although grasslands comprised most of the prairie islands at the study area, observations suggested that the limited woodlands on these islands are important for gartersnakes prior to and during hibernation along the Platte River in central Nebraska. Areas with large trees, such as Plains Cottonwoods (Populus deltoides), appeared to provide overwintering sites. In central Nebraska, riparian woodlands continue to be cleared to enhance habitat for endangered and threatened species such as Whooping Cranes (Grus americana), but some of these islands originally contained trees prior to European settlement. Conservation of at least some woodland habitats appears important for overwintering gartersnakes in central Nebraska.

Range Expansion of the Cleptoparasitic Orchid Bee Aglae caerulea in the Pantanal of Mato Grosso, Brazil

In the present study, a new occurrence of Aglae caerulea Lepeletier & Audinet-Serville is reported within a few km of the seasonal flooded plain limits of the Pantanal in the Paraguay basin, reinforcing the idea that this species coexists with its hostess Eulaema nigrita, one of the most common species catalogued in several habitats surveyed in the biome. After 18 months of sampling and no A. caerulea male attracted to the baits, methyl cinnamate was added to the set of fragrances available in the field. During four weeks in May and one week in June 2018, a total of 11 males of A. caerulea were attracted to the new bait in the gallery forest of São Vicente Range. With this most recent record, we expand the ranges of occurrence to the north-eastern border of the Pantanal of Barão de Melgaço, in Mato Grosso, Brazil. Future expeditions in the Pantanal of Mato Grosso and Mato Grosso do Sul should record this cleptoparasitic species from southern to western Paraguay river basin, to reduce the biogeographical gaps in this peculiar tribe of corbiculate bees. The cleptoparasitic species A. caerulea may be recorded when adequate field studies and collections are made from the seasonal floodplain habitats to karstic habitats (dry forests) along the Pantanal border.

Ancient Egyptian mummified shrews (Mammalia: Eulipotyphla: Soricidae) and mice (Rodentia: Muridae) from the Spanish Mission to Dra Abu el-Naga, and their implications for environmental change in the Nile valley during the past two millennia

Excavation of Ptolemaic Period (ca. 309–30 BC) strata within Theban Tombs 11, 12, -399-, and UE194A by the Spanish Mission to Dra Abu el-Naga (also known as the Djehuty Project), on the west bank of the Nile River opposite Luxor, Egypt, yielded remains of at least 175 individual small mammals that include four species of shrews (Eulipotypha: Soricidae) and two species of rodents (Rodentia: Muridae). Two of the shrews (Crocidura fulvastra and Crocidura pasha) no longer occur in Egypt, and one species (Crocidura olivieri) is known in the country only from a disjunct population inhabiting the Nile delta and the Fayum. Although deposited in the tombs by humans as part of religious ceremonies, these animals probably derived originally from local wild populations. The coexistence of this diverse array of shrew species as part of the mammal community near Luxor indicates greater availability of moist floodplain habitats than occur there at present. These were probably made possible by a greater flow of the Nile, as indicated by geomorphological and palynological evidence. The mammal fauna recovered by the Spanish Mission provides a unique snapshot of the native Ptolemaic community during this time period, and it permits us to gauge community turnover in the Nile valley of Upper Egypt during the last 2000 years. It also serves as a relevant example for understanding the extinction and extirpation of mammal species as effects of future environmental changes predicted by current climatic models.

The importance of environmental differences in the structuring of rotifer functional diversity

A dynamic change in environmental conditions among floodplain habitats with different geomorphology might be a significant trigger in determining rotifer functional diversity. The aim of the study was to test the importance of environmental differences between several waterbody types, their positions within the floodplain and supporting microcrustacean communities in the structuring of rotifer functional feeding guilds. The study was conducted in Kopački rit floodplain during 2008 at five sites (two lakes, two channels and the main river). ANOSIM showed a significant difference in spatial distribution among rotifer feeding guilds. Redundancy analyses indicated biotic variables to significantly influence rotifer functional diversity in lake systems while in channel environments and the main riverbed guild representation was mainly influenced by limnological variables. Individual guild abundance changed relative to the site position within the floodplain as well, where the increased distance from the main riverbed resulted in increased rotifer numbers, and a different proportion of microfilter-feeders and macrofilter-feeders was recorded. The multiple linear regression showed a significant relation of macrofilter-feeder rotifers with microcrustaceans pointing to notable exploitative competition among these groups. The results highlight the ecological importance of all types of natural floodplain habitats necessary for preserving and maintaining the rotifer diversity.