Invasive carps are ecologically and economically problematic fish species in many large river basins in the United States and pose a threat to aquatic ecosystems throughout much of North America. Four species of invasive carps: black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis), are particularly concerning for native ecosystems because they occupy and disrupt a variety of food and habitat niches. In response, natural resource agencies are developing integrated pest management (IPM) plans to mitigate invasive carps. Control tools are one key component within a successful IPM program and have been a focal point for development by governmental agencies and academic researchers. For example, behavioural deterrents and barriers that block migratory pathways could limit carps range expansion into new areas, while efficient removal methods could suppress established carp populations. However, control tools are sometimes limited in practice due to uncertainty with deployment, efficacy and availability. This review provides an overview of several emerging modelling approaches and control technologies that could inform and support future invasive carp IPM programs.
Livestock depredation can be devastating to both farmers and the species considered responsible if they are subsequently persecuted. Many proposed conflict solutions are limited in their uptake because they may be short-term, localised, expensive or species-specific. Livestock guarding dogs have been a successful solution in many parts of the world, however recommended imported breeds are generally expensive or inaccessible to many rural farmers. In this study, we report on a program placing local Tswana dogs with farmers in Botswana as a tool to reduce livestock loss. Seventy-five farmers who experienced high conflict from carnivores in both rangelands and wildlife areas were selected to receive a Tswana puppy. Puppies were monitored regularly to determine their performance, survival and owner attitudes toward wildlife. From initial baseline reports of goat losses before farmers received a puppy, loss declined by at least 85% over the following three years. Farmers were very satisfied with the performance of their livestock guarding dog and attitudes toward protection and tolerance of wildlife improved after one year of receiving a puppy. Our study suggests locally bred Tswana dogs are an effective solution for livestock at risk to depredation, particularly for rural farmers and development of community-led programs can be further used to reduce conflict.
In a recent study, we showed how local-scale climate change impacts (increased temperature, reduced rainfall, shifts in peak rainfall) affected the hydrology of a channelised lowland European river (reduced flow, reduction in flood events, increased siltation, macrophyte growth), allowing native fish species to recolonise the bankside zone and reduce the density of invasive round goby Neogobius melanostomus by effectively removing its preferred habitat, rip-rap bank stabilisation. Here, we report on a follow-on study whereby stretches of the newly vegetated bank were stripped back to clean rip-rap to assess whether presence/absence of rip-rap was the major factor affecting non-gobiid, tubenose goby Proterorhinus semilunaris and round goby abundance. Our results confirmed rip-rap as a major factor increasing round goby abundance, and hence invasion success, on European rivers, while vegetated banks saw an increase in the abundance and diversity of non-gobiid species. While tubenose gobies showed no preference for habitat type, their numbers were significantly reduced in rip-rap colonised by larger and more aggressive round gobies. We discuss our results in light of recent artificial bank restoration measures undertaken on the Danube and Rhine and the potential role of round goby as a flagship species for cost-effective, large scale river bank restoration projects with multiple ecosystem benefits.