Browsing by Author "Shivambu, Tinyiko Cavin."

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Aspects of the ecology of invasive rose-ringed parakeets (Psittacula krameri) in eThekwini Metropolitan, KwaZulu-Natal Province, South Africa.
(2021) Shivambu, Tinyiko Cavin.; Downs, Colleen Thelma.
Globally, the rose-ringed parakeet Psittacula krameri (Scopoli, 1769) has been cited as one of the world’s worst gregarious invasive parrot species, having established breeding colonies successfully outside its native distribution range. The rapid expansion of its breeding population has been considered a major threat to the economy, agricultural production, biodiversity, human health and social life. To date, the rose-ringed parakeet’s population has been reported in ca. 35 countries and the pet trade is the main introduction pathway of this species across the globe. In South Africa, rose-ringed parakeets were introduced as pets in the 1900s. Their breeding population has successfully established in several cities, particularly in Johannesburg and eThekwini Metropole. Although their population seems to be expanding at an alarming rate, little is currently known about their population size, breeding status, and feeding biology. This includes public knowledge and perception towards them as invasive species. Moreover, impacts (environmental and socio-economic) and areas that are at risk of becoming invaded by rose-ringed parakeets and other selected invasive bird species are unknown. This study conducted monthly surveys in the greater Durban (eThekwini) Metropole, KwaZulu-Natal Province, South Africa, from August 2018 to December 2019, to determine the rose-ringed parakeet’s population size, feeding biology and breeding status. A questionnaire survey was developed to determine the public knowledge and perception of parakeets. The species distribution modelling and Generic Impact Scoring Scheme were also used to investigate areas that are likely to be invaded and potential impacts (environmental and socio-economic) associated with rose-ringed parakeets, and other selected introduced bird species. A total of five major roost sites with an overall mean monthly population size of 1,783 rose-ringed parakeets were located. Most of these roost sites were found around urban (public) parks and shopping centres. Seven bird species were found sharing communal roosting sites with rose-ringed parakeets, with the common myna Acridotheres tristis recorded the most. We identified 72 nests within 39 breeding sites, with the first breeding season accounting for 53 active nests and the second breeding season with 59 active nests. Rose-ringed parakeets used four tree species for nesting, with white milkwood Sideroxylon inerme being the most preferred tree species (71%). The recorded rose-ringed parakeet fledglings ranged between 1 – 3 per nest, and their numbers differed significantly between the seasons. A total of 63 feeding sites were identified, with most of them in the urban built land-use cover type. Rose-ringed parakeets were observed feeding on 31 fruiting/flowering trees and one insect species, with fleshy fruits (58%) and flowers (19%) primarily relied on. For our survey questionnaire, a total of 312 participants responded to the survey, with 92.5% being familiar with parakeets. A large population of rose-ringed parakeets were seen in shopping centres (38.5%), suburbia (26.3%), and golf courses (19.6%). Most survey respondents (58.3%) indicated that they provide feeding stations for these parakeets, and 57.7% did not consider them pests. In terms of invasion risk, the rose-ringed parakeets were found to have large areas in South Africa with high climatic suitability, and their impacts were both socio-economic and environmental. Agricultural production was the main impact through socio-economic, while competition and impact on other animals were the main environmental impacts. In general, this study showed continuous growth in the rose-ringed parakeets’ numbers in eThekwini Metropole, indicating that their population is breeding at an average rate. Our study also showed that rose-ringed parakeets feed on various food items, suggesting that they are generalist-opportunistic feeders. As a result, this plasticity in feeding behaviour may likely enhance competitive interactions with other species, contribute to seed dispersal, and increase damage to crops. Parakeets are not perceived as pests by most of the respondents in the eThekwini Municipality. This positive perception may have been exacerbated by the public’s poor knowledge regarding their impacts on biodiversity, economy, human social life, and health. Therefore, we recommend introducing environmental education, which involves the engagement with the community members and eThekwini Municipality. This may assist in making an informed decision regarding the control of this species in the area. Monitoring of rose-ringed parakeet’s population size, breeding status, feeding biology, and movement patterns should continue so that adequate information can be acquired on their biology. In conclusion, our results highlight the importance of studying rose-ringed parakeet’s ecology, which provides reliable data that can be considered in decision-making, management and eradication plans for parakeets in South Africa.
Assessing the trade of reptile species in the South African pet trade.
(2021) Mantintsilili, Asekho.; Downs, Colleen Thelma.; Shivambu, Tinyiko Cavin.; Shivambu, Ndivhuwo.
Despite the negative impacts that the pet trade has on the native and non-native biodiversity, economy and human health, the research suggests that the demand for pets and the extent of trade in live animals as pets has increased dramatically over the years. As a result, many species, including reptiles, have been translocated and introduced into new or non-native environments. Some of these have established feral populations, become invasive and are causing significant environmental and socio-economic impacts on non-native environments. Reptiles are among the most popular groups of animals in the pet trade industry globally. Trade in pet reptiles in South Africa is large and one of the major pathways through which non-native species, including invasive species, are introduced into the country. Despite this, little is known about the dynamics of the wildlife trade in pet reptiles globally. To understand the dynamics of the global trade in pet reptiles, we carried out a comprehensive literature search to gather relevant information from reptile pet trade-based publications. We further compiled a list of traded pet reptiles from all South African physical pet stores and online advertising websites to determine which species are traded, pose an invasion risk and have potential environmental and socio-economic impacts. We found a total of 39 publications based on the reptile pet trade from 1994 – 2021 worldwide. Our analyses revealed that the research effort was not uniform globally, with the majority (63.6%) of all relevant studies originating from three continents (Asia, Europe, and North America). Moreover, the United States of America (North America) and Indonesia (Asia) produced the greatest research outputs (12.1% each) compared with other countries across the world. We found at least 1140 reptile species belonging to 60 families involved in the global pet trade, with invasive red-eared slider Trachemys scripta elegans being the most frequently studied species (number of studies = 23/39). Of the recorded species, at least 79 are invasive, 46 endangered, 29 critically endangered, while only 546 are CITES-listed. In terms of reptile species sold in South Africa, we recorded a total of 2771 individuals representing 88 unique reptiles, 69 from physical pet stores and 18 from online advertising websites. KwaZulu-Natal, Gauteng and Western Cape Provinces had the highest number of pet stores and online advertising websites; therefore, they subsequently recorded the highest number of pet reptiles compared with other provinces. Physical pet stores were found to have the highest number of species compared to online trade. Of the recorded species, 76 are nonnative, and 15 of these are invasive to South Africa. Moreover, only 32 pet reptiles are listed under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). For current distributions, 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. Some species, such as Burmese pythons Python bivittatus, showed low invasion risk based on climatic suitability. However, given their large body size, history of invasion and their popularity in the pet trade, they are most likely to escape or be released from captivity and become invasive. A total of 76 reptile species were assessed for environmental and socio-economic impacts using the Generic Impact Scoring System (GISS), Environmental Impact Classification for Alien Taxa (EICAT), and Socio-Economic Impact Classification for Alien Taxa (SEICAT). Using GISS, we found that 13 species had environmental impacts (E_GISS), while 11 species had socio-economic impacts (SE_GISS). For EICAT and SEICAT, 13 species had environmental impacts, and eight had socio-economic impacts, respectively. The most popular pet species, red-tailed boa Boa constrictor, green iguana Iguana iguana, P. bivittatus, T. elegans, and central bearded dragon Pogona vitticeps had impacts in all the three scoring schemes. The later species and corn snake (Pantherophis guttatus) scored the highest for all impact schemes. Species sold in high numbers, with large climatically suitability and potential impacts, are more likely to establish feral populations and become invasive should they escape or be released from captivity. We, therefore, recommended that the trade in pet reptiles should be constantly monitored to avoid new introductions and the implications that the pet trade may have to the country.
House Crow (Corvus splendens) eradication measures from eThekwini Municipality, KwaZulu-Natal, South Africa.
(2018) Nxele, Beka J.; Shivambu, Tinyiko Cavin.
Abstract available in PDF file.