An impact assessment of alien invasive plants in South Africa generally dispersed by native avian species

Invasive alien plant species have been identified as a major threat to biodiversity and the relationship with native avian dispersers may increase their invasion potential. The impact of invasive plant species needs to be quantified using comparable assessment tools across different habitats and species to allocate limited resources to high-priority species. Here, we used the Generic Impact Scoring System (GISS) to assess the impacts of 16 fleshy-fruited alien invasive plant species in South Africa generally dispersed by native avian species. The results showed that fleshy-fruited invasive species have both environmental and socio-economic impacts. The cumulated impact scores for lantana (Lantana camara) and the tree of heaven (Ailanthus altissima) were the highest, with scores of 42 and 32, respectively. Some species, such as white mulberry (Morus alba), camphor tree (Cinnamomum camphora), American bramble (Rubus cuneifolius) and Brazilian pepper tree (Schinus terebinthifolius), had low overall impact scores of 8, 18, 14 and 16, respectively, but scored the maximum impact of 5 for certain mechanisms. Environmental impacts of fleshy-fruited invasive plant species had a high impact magnitude through effects on the ecosystem and vegetation. Socio-economic impacts were mainly through effects on forest production, agriculture and human health. Species with large crop sizes, small seeds and fruit sizes had higher environmental and socio-economic impact magnitude. The information generated in this study is important for guiding resource allocation and preventing the uncontrolled introduction of invasive species in South Africa. The impact of the fleshy-fruited invasive species transcended sectors and, therefore, effective management of invasive species will require the collaboration of multiple and inter-sectoral stakeholders in South Africa.https://neobiota.pensoft.nethj2022Mammal Research InstituteZoology and Entomolog

Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas

Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and observed, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, and DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria, and Eukarya in different combinations were detected for each layer. Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine species were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin of fracture fluids is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing

Non-native small mammal species in the South African pet trade

Non-native small mammals are amongst the most popular species traded as pets around the world. Some of these mammals have become invasive through various pet trade releases and escapees in most countries. In South Africa, several nonnative small mammals have been introduced for pet trade purposes. We assessed the sale of non-native small mammals in South Africa from September 2018 to 2019 to determine their abundance and degree of trade online and in pet shops. A total of seven websites were recorded selling 2,681 individuals representing 24 species belonging to seven taxonomic orders. For physical pet shops, 19,391 individuals representing 16 species and seven orders were recorded from 122 pet shops. Rodents and primates were the most dominant groups in both online and pet shops. The most common small mammal species traded were the Norwegian rat Rattus norvegicus, the guinea pig Cavia porcellus, the European rabbit Oryctolagus cuniculus and the house mouse Mus musculus. Prices ranged from ZAR9.00 to ZAR12,000.00, with rodents offered at relatively low prices. The most abundant species traded were relatively cheap when compared with the least abundant species and CITES species were more expensive than non-CITES species. Species with high abundances traded at low prices and have a history of invasion through pet trade releases and escapes pose an invasion risk in South Africa. Therefore, their trade should be strictly regulated

Occurrence record of and possible invasion by scarlet sage (Salvia coccinea Buc’hoz ex Etl.) in South Africa

The scarlet sage, Salvia coccinea, was first detected in Northern Province, South Africa in 1905, in what is now Limpopo Province. However, its presence and suitability in South Africa remains undocumented. We conducted vegetation surveys to determine the actual distribution and to incorporate species distribution modelling in order to determine the potential distribution of this species. Twelve populations were documented from different localities. The species distribution model was successful in predicting areas that are climatically suitable for this species to survive in South Africa. The wide distribution and high density suggest a long residency time. Thus we conclude that its recent invasion of the wild has most probably originated in gardens

Population estimates of non-native rose-ringed parakeets Psittacula krameri (Scopoli, 1769) in the Durban Metropole, KwaZulu-Natal Province, South Africa

Rose-ringed parakeetsPsittacula krameriare one of the most widely distributed urban avian invader species present in similar to 35 countries with population sizes increasing. These parakeets were introduced to South Africa as part of the pet trade, and feral populations have established in several urban areas since and are of concern. We, therefore, conducted monthly surveys between August 2018 - December 2019 in the greater Durban Metropole, KwaZulu-Natal Province, to determine their population size and roosting sites. In addition, we recorded bird species that communally roosted with rose-ringed parakeets, and tree species characteristics that they used for roosting. We identified five main roost site areas with an overall mean (+/- SD) monthly population size of 1 783.3 +/- 505.2 rose-ringed parakeets. There was an increase in rose-ringed parakeet numbers, particularly in August and December after their breeding. Most rose-ringed parakeets were recorded in the north, with fewer in the south of the metropole; and many were located around shopping centres and parks. A total of seven bird species communally shared roost sites with rose-ringed parakeets, with the non-native common mynaAcridotheres tristisbeing the species that frequently shared roosts with parakeets. Three tree species were used as roosts, with the Natal mahoganyTrichilia emeticaand the giant palmRaphia australis, so being the preferred roost tree species. The results showed variations in the measured tree traits and the number of individual parakeets roosting per tree species. The population size of non-native rose-ringed parakeets showed persistent growth, and it is, therefore, suggested that control measures for this species are introduced before its population expands further

Exotic gastropods for sale: an assessment of land and aquatic snails in the South African pet trade

Gastropods are amongst the most popular of the Mollusca in the pet trade, with globalisation being the main contributing factor facilitating their establishment globally. Although it is known that gastropods are kept as pets in South Africa, relatively little has been documented on the trade for this group. Physical pet stores selling gastropod species were surveyed seasonally in South Africa, aiming to determine 1) the types of species sold, including their trade popularity, trade volume, and the biogeographic realms they originated from, and 2) seasonal variations in gastropod species traded. Six gastropod species were recorded in the South African pet stores with three known invasives (Achatina fulica, A. immaculata, and Pomacea canaliculata). Of these species, the African giant snail A. fulica and the channeled golden apple snail P. canaliculata were the species with higher trade popularity throughout the year. The trade of the other species fluctuated with seasons among pet stores and provinces. Gastropod species sampled in this study originated from four biogeographic realms, with two species from the Afrotropical and Neotropical realms, and one each from the Indomalayan and the Palaearctic. The number of gastropod individuals observed in this study was relatively large; as a result, they may pose a potential risk of invasion should they be released or escape captivity. The pet trade industry at a national level needs to be regularly monitored and the policies on selling invasive non-native species should be implemented to avoid the introduction and establishment of potential invaders

Impact assessment of seven alien invasive bird species already introduced to South Africa

Globally, various avian species have been introduced accidentally and deliberately by humans through different pathways. Some of these species were able to establish, multiply, and become invasive. In this study, we identified areas that are climatically suitable for seven introduced invasive bird species and assessed the environmental and socio-economic impacts associated with the selected bird species in South Africa. We used present distribution records to predict potential climatic suitability distributions and used the Generic Impact Scoring Scheme to assess the impacts associated with seven invasive bird species in South Africa. We found that all the seven species were climatically suitable to South Africa and Passer domesticus, Sturnus vulgaris, and Anas platyrhynchos each had relatively large climatic suitability distributions. The climatic suitability for all the species was within their occurrence ranges in and outside South Africa. For impact assessments, we found that all seven selected species had impacts, with A. platyrhynchos, Acridotheres tristis, Columba livia, and Psittacula krameri having the highest overall impacts respectively. The socio-economic impact ranked higher than environmental impact for all species. The socio-economic impacts were frequently through agricultural production and human infrastructure, while the environmental impact was mostly through impacts of birds on other animals and competition. These need to be incorporated in decision-making and eradication plans for these alien invasive birds in South Africa

Survey of non-native small mammals traded in South Africa

The sale of live non-native animals has become a social norm and is of global concern. The pet trade industry has become one of the main pathways where non-native small mammals are introduced worldwide. We conducted a questionnaire survey in South African pet shops from September 2018 to September 2019 to gain insights into non-native small mammalian species trade in South Africa. We also investigated whether the pet shop owners were aware of the South African National Environmental Management: Biodiversity Act (NEM: BA; No. 10 of 2004), which regulates and provides management and conservation of the country's biodiversity. A total of 111 pet shop owners/managers responded to the survey, with 26.6% of the owners reporting the sale of birds, 25.1% of fish and 22.5% of mammals. A total of 16 non-native small mammalian species were reported sold, with European rabbits (Oryctolagus cuniculus), Norwegian rats (Rattus norvegicus) and house mice (Mus musculus) being the most commonly sold pets. We found that breeders, animal rescues and pet shops were the major suppliers of small mammal pets, and in terms of the regulation, most respondents (67.8%) were aware of NEM: BA. However, despite the knowledge of the regulations, some of the traded species pose a serious invasion threat. As a result, we recommend increased regulation, monitoring and public awareness to prevent the potential negative impacts associated with non-native mammal species in South Africa.DSI-NRF Centre of Excellence for Invasion Biology, University of Stellenbosch (ZA); Ford Wildlife Foundation (ZA); University of KwaZulu-Natal (ZA); National Research Foundation (ZA).http://www.wileyonlinelibrary.com/journal/aje2023-03-30hj2022Mammal Research InstituteZoology and Entomolog

Online and pet stores as sources of trade for reptiles in South Africa

The ever-increasing human population, globalisation, and desire to keep pets have resulted in the translocation of many species into non-native environments. As a result, some of the non-native reptile species have been introduced to South Africa through the pet trade. However, little is known about the extent of trade in reptiles via online and physical pet stores in South Africa and their potential climatically suitable areas. We assessed the physical pet store and online trade of reptiles in South Africa. We found 69 physical pet stores and 18 online advertising websites selling 1,912 individuals of 66 species and 859 individuals of 50 reptile species, respectively. In total, we found 88 unique species representing 18 families from both sources, of which 86.4% were non-native species and 32 species were CITES-listed. Snakes were the most dominant (76.1%) traded group. Ball python Python regius (n = 601), corn snake Pantherophis guttatus (n = 553) and central bearded dragon Pogona vitticeps (n = 419) were the most-traded reptiles. Prices ranged from ZAR100.00 to ZAR6,000.00, with sharp-nosed viper Deinagkistrodon acutus acutus being the most expensive species. For present distributions, the red-eared slider Trachemys scripta elegans, P. guttatus, and Western diamondback rattlesnake Crotalus atrox had the largest predicted climatic suitability. The future predictions for the latter two species were predicted to increase while red-eared slider suitability shifted. Most popular species were available in large volumes, sold at relatively low prices and had high climatic suitability, representing a high potential invasion risk. We, therefore, propose that the existing pet trade regulations should be revised to include a more restricted trade on the trade of endangered, non-CITES listed and potential invasive pet species.The National Research Foundation (NRF) (ZA), the University of KwaZulu-Natal (ZA), and the DSI-NRF Centre of Excellence for Invasion Biology, University of Stellenbosch (ZA).https://www.elsevier.com/locate/jnc2023-03-03hj2022Mammal Research InstituteZoology and Entomolog

Genetic identification of freely traded synanthropic invasive murid rodents in pet shops in Gauteng Province, South Africa

Although synanthropic invasive murid rodents are freely traded in pet shops in South Africa, their taxonomic identities, however, remain largely unknown. Twenty-four murid rodents were sampled from pet shops in four of the five municipalities in Gauteng Province, South Africa for genetic identification using mitochondrial cytochrome b (mtDNA) sequence data. Distance-based Neighbour-Joining (NJ), character-based maximum likelihood (ML) and model-based Bayesian inference (BI) were used to infer the relationship between the pet murid rodents. Brown rats (Rattus norvegicus) and house mice (Mus musculus) were the most dominant species in the pet shops. The results demonstrated that pet shop owners lacked the taxonomic expertise to identify murid rodent species they trade in. For example, the juveniles of brown rats were misidentified as adults of the house mouse. The murid rodents sampled in the current study were genetically affiliated to both wild and laboratory strains of R. norvegicus and M. musculus. The results of the BI showed that the pet murid rodents were in the terminal clades as those of conspecifics in NCBI GenBank reference sequences. The molecular data used in the current study may be useful for developing national policies and regulations for synanthropic invasive murid rodents in the pet trade industry in South Africa