Data were generated to investigate the influence of bed roughness on the dynamics of large sand-bed rivers like the South Saskatchewan, Canada. The influence of roughness was investigated by using a numerical model to simulate the evolution of the river bed for a hypothetical sand-bed river modelled on the South Saskatchewan. The model generated information on the evolving river bed topography, water depth, flow velocities and sediment transport rates, over a period of 28 years...

Parasites can negatively affect the reproductive success of hosts. Placental species may be particularly susceptible, because parasite-induced stress during pregnancy could potentially influence embryo development. Here we examine the consequences of a trematode infestation (black spot disease, BSD) for fetal development and adult behavior in 19 natural populations of the placental live-bearing fish species Poeciliopsis retropinna (Poeciliidae) in Costa Rica. First, we observed substantial variation in parasite infestation among populations which correlated with a number...

This dataset describes hourly time series of discharge and suspended sediment flux at four sites in the Vietnamese Mekong Delta (Chau Doc, Tan Chau, Can Tho and My Thaun) for the period 2005 – 2015. This data was calculated from historic Acoustic Doppler Current Profiler (aDcp)data obtained as part of routine flood monitoring conducted by the Vietnamese Hydrological Agency. The data were collated by the authors. The data were processed to back out sediment fluxes...

The leaf economics spectrum (LES) describes consistent correlations among a variety of leaf traits that reflect a gradient from conservative to acquisitive plant strategies. So far, whether the LES holds in wetland plants at a global scale has been unclear. Using data on 365 wetland species from 151 studies, we find that wetland plants in general show a shift within trait space along the same common slope as observed in non-wetland plants, with lower leaf...

The placenta is a complex life-history trait that is ubiquitous across the tree of life. Theory proposes that the placenta evolves in response to high performance-demanding conditions by shifting maternal investment from pre- to post-fertilization, thereby reducing a female’s reproductive burden during pregnancy. We test this hypothesis by studying populations of the fish species Poeciliopsis retropinna in Costa Rica. We found substantial variation in the degree of placentation among natural populations associated with predation risk:...

1. Environmental DNA (eDNA) metabarcoding has revolutionised biomonitoring in both marine and freshwater ecosystems. However, for semi-aquatic and terrestrial animals, the application of this technique remains relatively untested. 2. We first assess the efficiency of eDNA metabarcoding in detecting semi-aquatic and terrestrial mammals in natural lotic ecosystems in the UK by comparing sequence data recovered from water and sediment samples to the mammalian communities expected from historical data. Secondly, using occupancy modelling we compared the...

Invasive freshwater fish systems are known to readily hybridize with indigenous congeneric species, driving loss of unique and irreplaceable genetic resources. Here we reveal that newly discovered (2013-2016) evolutionarily significant populations of Korogwe tilapia (Oreochromis korogwe) from southern Tanzania are threatened by hybridization with the larger invasive Nile tilapia (Oreochromis niloticus). We use a combination of morphology, microsatellite allele frequencies and whole genome sequences to show that O. korogwe from southern lakes (Nambawala, Rutamba and...

Male alternative reproductive strategies are found in some species of most major animal taxa, but are especially widespread in fishes. Mature males of the shortfin molly, Poecilia gillii, display extensive variation in size and morphology. We devised a field test of a priori hypotheses regarding the interrelationships between male size, colouration, morphology, and mating tactics. Males did not occur in discrete size classes, but instead occurred in a size and morphological continuum. Large males exhibited...

The final 10 Myr of the Paleozoic saw two of the biggest biologic crises in Earth history: the Middle Permian extinction (often termed the Guadalupian-Lopingian extinction, GLE) that was followed 7–8 Myr later by Earth’s most catastrophic loss of diversity, the Permian-Triassic mass extinction (PTME). These crises are not only manifest as sharp decreases in biodiversity and - particularly for the PTME - total ecosystem collapse, but they also drove major changes in biological morphological...

The early detection of invasive non-native species (INNS) is important for informing management actions. Established monitoring methods require the collection or observation of specimens, which is unlikely at the beginning of an invasion when densities are likely to be low. Environmental DNA (eDNA) analysis is a highly promising technique for the detection of INNS – particularly during the early stages of an invasion. Here, we compared the use of traditional kick-net sampling with two eDNA...