Publications by authors named "Carl D Sayer"

Hybridization plays a pivotal role in evolution, influencing local adaptation and speciation. However, it can also reduce biodiversity, which is especially damaging when native and non-native species meet. Hybridization can threaten native species via competition (with vigorous hybrids), reproductive resource wastage and gene introgression.

View Article and Find Full Text PDF

Accurate hydrological data with high spatial resolution is important for flood risk and water resource management, particularly under the context of climate change. The cost of monitoring networks, as well as the characteristics of the hydrological environment itself, can be a barrier to meeting these data requirements, however. This study covers the design and testing of a low-cost, "build-it-yourself", instream water depth sensor providing an assessment of its potential in future hydrological monitoring projects.

View Article and Find Full Text PDF

Microplastics are a globally pervasive pollutant with the potential to directly impact species and accumulate in ecosystems. However, there remains a relative paucity of research addressing their accumulation in freshwater ecosystems and a near absence of work in crayfish, despite their high ecological and economic importance. This study investigated the presence of microplastics in the invasive signal crayfish along a stream urbanization gradient.

View Article and Find Full Text PDF

Since its inception, the theory of alternative equilibria in shallow lakes has evolved and been applied to an ever wider range of ecological and socioecological systems. The theory posits the existence of two alternative stable states or equilibria, which in shallow lakes are characterised by either clear water with abundant plants or turbid water where phytoplankton dominate. Here, we used data simulations and real-world data sets from Denmark and north-eastern USA (902 lakes in total) to examine the relationship between shallow lake phytoplankton biomass (chlorophyll-a) and nutrient concentrations across a range of timescales.

View Article and Find Full Text PDF

Fishes stocked for recreation and angling can damage freshwater habitats and negatively impact biodiversity. The pond-associated crucian carp (Carassius carassius) is rare across Europe and is stocked for conservation management in England, but its impacts on pond biota are understudied. Freshwater invertebrates contribute substantially to aquatic biodiversity, encompassing many rare and endemic species, but their small size and high abundance complicate their assessment.

View Article and Find Full Text PDF

Dramatic declines in diurnal pollinators have created great scientific interest in plant-pollinator relationships and associated pollination services. Existing literature, however, is generally focused on diurnal pollinating insect taxa, especially on Apidae (Hymenoptera) and Syrphidae (Diptera) pollinators, while nocturnal macro-moths that comprise extremely species-rich flower-visiting families have been largely neglected. Here, we report that in agricultural landscapes, macro-moths can provide unique, highly complex pollen transport links, making them vital components of overall wild plant-pollinator networks in agro-ecosystems.

View Article and Find Full Text PDF

Submerged macrophytes play a key role in north temperate shallow lakes by stabilizing clear-water conditions. Eutrophication has resulted in macrophyte loss and shifts to turbid conditions in many lakes. Considerable efforts have been devoted to shallow lake restoration in many countries, but long-term success depends on a stable recovery of submerged macrophytes.

View Article and Find Full Text PDF

A fundamental consideration for the conservation of a species is the extent of its native range, that is, regions naturally colonized. However, both natural processes and human-mediated introductions can drive species distribution shifts. Ruling out the human-mediated introduction of a species into a given region is vital for its conservation, but remains a significant challenge in most cases.

View Article and Find Full Text PDF

The conservation of threatened species must be underpinned by phylogeographic knowledge. This need is epitomized by the freshwater fish Carassius carassius, which is in decline across much of its European range. Restriction site-associated DNA sequencing (RADseq) is increasingly used for such applications; however, RADseq is expensive, and limitations on sample number must be weighed against the benefit of large numbers of markers.

View Article and Find Full Text PDF

Tributyltin (TBT) is an organotin compound used since the early 1960s as a biocide in boat antifouling paints. Its use has been linked to a host of negative effects in marine ecosystems including malformations and imposex in Mollusca and acute toxicity in many other aquatic animals. Yet, the consequences of TBT use in freshwaters are largely unknown.

View Article and Find Full Text PDF