Karl Patterson Schmidt

Four anguillid eel species occur in the western Indian Ocean rivers of Africa: Anguilla bengalensis, Anguilla bicolor, Anguilla marmorata and Anguilla mossambica. These catadromous fishes face multiple stressors, including habitat alteration and deterioration, barriers to migration, pollution and the adverse impacts of alien species, but knowledge of eel species occurrence, abundance and ecology in Africa remains poor.This study investigated the present and historical distribution of anguillid eels and the potential associated drivers of declines at the southern extremities of their ranges in South Africa. Data analysed included sampling conducted in KwaZulu–Natal and Eastern Cape between 2015 and 2020, and secondary data extracted from databases, museums and local management agencies.The median extent of inland penetration increased as follows: 22 km for A. bicolor, 29 km for A. marmorata, 94 km for A. bengalensis and 293 km for A. mossambica. The median altitude followed a similar pattern.Extent of occurrence analyses were carried out at the regional level in KwaZulu–Natal. The sampling data on present distribution (2015–2020), compared with historical data, suggests declines in the extents of occurrence of the four eel species in KwaZulu–Natal, ranging between 31 and 48% in the last 30 years and between 35 and 82% since the 1950s.With increasing human threats in the region, especially from watercourse modification and water abstraction, further declines for these species are expected. Conservation measures recommended include the maintenance or restoration of the ecological connectivity of important rivers and the implementation of freshwater protected areas. Although eels are at present not widely exploited in South Africa, there is a need for fisheries regulations to manage sustainable commercial exploitation.

Environmental niche models (ENMs) are commonly used to inform management of invasive species, but invasive species often violate two key assumptions of ENMs which assert that species’ ecological niches are stable in space and time, and that organisms are in equilibrium with their environment. The Am…

Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolat…

Emergent infectious disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) represents one of the major causes of biodiversity loss in amphibians. While Bd has affected amphibians worldwide, Bsal remains restricted to Asia and Europe, b…

Spatial patterns of biodiversity are inextricably linked to their collection methods, yet no synthesis of bias patterns or their consequences exists. As such, views of organismal distribution and the ecosystems they make up may be incorrect, undermining countless ecological and evolutionary studies.…

Aim: Future climate changes may affect species distribution and their genetic diversity, hampering species adaptation to a new climate or tracking the suitable conditions. Amphibians have high sensitivity to environmental degradation and changes in temperature and humidity. Thus, the expected climat…

A key assumption in species distribution modeling (SDM) with presence‐background (PB) methods is that sampling of occurrence localities is unbiased and that any sampling bias is proportional to the background distribution of environmental covariates. This assumption is rarely met when SDM practition…

Factors driving the spatial configuration of centres of endemism have long been a topic of broad interest and debate. Due to different eco‐evolutionary processes, these highly biodiverse areas may harbour different amounts of ancient and recently diverged organisms (paleo‐ and neo‐endemism, respecti…

Aim: To review the conservation status of Headwater catfish Ictalurus lupus (Girard,1859) in the United States, including quantifying environmental correlates with range contraction and hybridization and introgression with Channel catfish Ictalurus punctatus (Rafinesque, 1818) to inform conservatio…

Mexican islands are one of the most diverse territories in the world and consequently their conservation should be a national and international priority. Three main threats to islands’ diversity have been detected: invasive species, land use change and climate change. Most studies have been focused on invasive species and land use change. Actually, as far as we know, this work is the first approach to evaluate climate change impacts on the biodiversity of islands in Mexico. We had two main goals: to list the vertebrate species that have been registered in Mexican islands and to model the possible impacts of climate change in the distri- bution of islands’ vertebrates. To evaluate climate change impacts, we used the ecological niche modeling that relates geographic occurrences with environmental variables to create a bioclimatic profile that can be projected in other time and other geographic areas. In our results we obtained a list of species registered in Mexican islands that increased in more than twice the number of species acknowledged by the Mexican government and the ecological niche modeling of 54 vertebrate species. We found that the species list effort was very important, because knowing which species exist is the first step to preserve them. In terms of eco- logical niche modeling, we modeled mammals, reptiles and amphibians. From these three groups, reptiles were the group with greatest losses and more species in the top-ten vulnerable list. If we considered a no dispersion scenario, all evaluated species presented losses regarding their current potential distribution area. If the full dispersion scenario was taken into account, the net change value resulted positive for the majority of the species evaluated, consequently if no barriers exist and the dispersion ability is good enough, changes in climatic conditions might not be an important threat. However, this is not the case for most species eval- uated. Areas with a higher number of species (richest areas) do show changes in the future with shifts to the east and north of the country. Finally, we could find significant differences between times and scenarios in terms of suitable area losses. Greatest losses can be found in the long term RCP 8.5 Wm–2 in comparison to the long term RCP 4.5 Wm–2, meaning that the direction that humanity takes in terms of climate change will have consequences on island biodiversity. In this work, we did not take into account the sea level rise, which is expected to have important impacts on islands species.