A spatial ecological analysis of the reintroduction of the Eurasian beaver

As ‘nature’s ecological engineers’ beavers can intentionally modify their habitat by building structures. This ability can have wider environmental benefits, including benefits for other habitats and species. However, this ability to modify the environment can sometimes be destructive, bringing beavers into conflict with land managers and others. To understand the complex connections between Eurasian beavers and ecosystems, this study was based on R language analysis tool that used land cover types, river network distribution and observational record studies of Eurasian beavers to find their most preferred environmental resources and potential habitats. The results found that reintroduced Eurasian beavers have a high potential for settlement and dispersal in restored areas.

The “Secret Recipe” of Galápagos

Galápagos tortoises demonstrate the special “creative force” of evolution in the archipelago, having radiated into 15 species—each with a characteristic shell shape—within the last 3.2 million years. Formed over an active mid-ocean volcanic hotspot, Galápagos islands have also changed dramatically in the same period, providing new and diverse “petri dishes” for tortoise evolution. In these new homes, which are low, dry islands, where the tortoise’s main food is prickly pear cactus (which has concurrently evolved a protective treelike stature), tortoises evolved impressive new features, including saddlebacked shells and extra-long limbs. On all the islands where they occur, tortoises serve as “ecological engineers,” building suitable niches for themselves (and incidentally for other species). In the case of domed-shell tortoises, those niches include tortoise-maintained wallows, meadows, and migration trails. Heavily hunted in Galápagos history, most tortoise species are rebounding today, some from tortoises rediscovered in the novel places they had been carried by early mariners in their quest for food.

Abundance, Distribution, and Drivers of Microplastic Contamination in Urban River Environments

Given the persistence of microplastics in the environment and their potential toxicity to ecosystems, understanding of likely microplastic accumulation ‘hotspots’ in rivers is urgently needed. To contribute to this challenge, this paper reports results of a microplastic survey from a heavily urbanised catchment, the River Tame and four of its tributaries, which flows through the city of Birmingham, UK. All sediment sampled was found to contain microplastics with an average abundance of 165 particles kg−1. While urban areas generally have a greater abundance of microplastics as compared with rural, there is no simple relationship between microplastic numbers and population density or proximity to wastewater treatment sites. The greatest change in microplastic abundance was due to the presence of a lake along the course of the River Tame—i.e., flow velocities are reduced on entering the lake, which promotes the deposition of fine sediment and potentially microplastics. This suggests that the greatest concentrations of microplastics will not be found in-channel but rather on the floodplain and other low velocity environments such as meander cutoffs. We also identified a new mechanism of microplastic fixation in freshwater environments through ecological engineers, specifically caddisflies, that incorporated microplastics into their casing. These results highlight the need to explore further hydrodynamic and ecological impacts on microplastics fate and transport in rivers.

Abundance, Distribution and Drivers of Microplastic Contaminant in Urban River Environments

Given the persistence of microplastics in the environment and their potential toxicity to ecosystems, understanding of likely microplastic accumulation ‘hotspots’ in rivers is urgently needed. To contribute to this challenge, this paper reports results of a microplastic survey from a heavily urbanised catchment, the River Tame, which flows through the city of Birmingham, UK. All sediment sampled was found to contain microplastics with an average abundance of 165 particles kg-1. While urban areas generally have a greater abundance of microplastics as compared with rural, there is no simple relationship between microplastic numbers and population density or proximity to wastewater treatment sites. The greatest change in microplastic abundance was due to the presence of a lake along the course of the River Tame i.e. on entering the lake flow velocities are reduced which promotes the deposition of fine sediment and potentially microplastics. This suggests that the greatest concentrations of microplastics will not be found in-channel but rather on the floodplain and other low velocity environments such as meander cutoffs. We also identified a new mechanism of microplastic fixation in freshwater environments through ecological engineers, specifically caddisfly that incorporated microplastics into their casing. These results highlight the need to explore further hydrodynamic and ecological impacts on microplastics fate and transport in rivers.