A study of diel and seasonal patterns of loss of commercial lychee fruits to vertebrate frugivores: implications for mitigating a human-wildlife conflict.

Human-wildlife conflict is a growing threat to biodiversity, primarily involving damage to agricultural production. In Mauritius, the threatened Mascarene endemic Mauritian flying fox (Pteropus niger) has been subjected to five annual mass-culling campaigns since 2015, which failed their crop protection goals while raising the species' extinction risk. We evaluated seven non-lethal potential deterrent methods to mitigate flying fox as well as bird damage to ripening fruits in lychee orchards. This study was conducted in close collaboration with local small- and large-scale fruit growers, who occasionally influenced the number and spatial arrangement of trees assigned to treatments and controls. We estimated expected fruit yield per tree before ripening, collected fallen fruits weekly over the four-week fruiting season and categorized them by damage agent. At five control sites, flying foxes damaged 0-88% (mean = 43%) of fruits on unprotected lychee trees. Two sites likely experienced high nocturnal human disturbance, which may have skewed flying fox damage on the control trees; excluding these sites, damage averaged 66%. The lowest flying fox damage occurred when trees were covered by netting or parallel cords (<1%), followed by a nocturnal sound-light system (4%), a nocturnal sprinkler system (11%), local traditional nocturnal smoke and lights (19%), flags positioned above the trees (25%) and flags saturated with repellent odours and placed above the trees (38%). Bird damage was less than that from flying foxes (1-12%, mean = 6%) and similar in most treatments, including netting due to holes in the nets. Testing the sound-light system in one mango orchard resulted in a reduction of flying fox damage from 60% to 20%, but an increase in bird damage from 1% to 16%. Overall, we provide evidence that various non-lethal crop protection methods are effective, although to varying degrees. In comparison, mass-culling campaigns failed to improve overall fruit production. In addition to the benefits of netting, which can carry relatively high upfront costs, this study highlights the potential value of the sound-light and sprinkler systems.

Introduced species may pose one of the biggest threats to biodiversity conservation. Today, monitoring their status, distribution and abundance constitutes an important part of ecological and conservation studies throughout the world. In the Afrotropical Region (sub-Saharan Africa), avian introductions have attracted the attention of many researchers, but there is a lack of a comprehensive review of this subject on a continental scale. The presented paper constitutes an attempt to overview the status, distribution, threats and control measures of birds introduced to sub-Saharan Africa in the last 200 years. This review lists 146 bird species introduced to sub-Saharan Africa. Only 49 (33.6%) of them have developed viable populations and only 7 (4.8%) became invasive species, namely Passer domesticus, Sturnus vulgaris, Acridotheres tristis, Corvus splendens, Columba livia var. domestica, Psittacula krameri and Pycnonotus jocosus. Data on distribution of most introduced species are provided, together with information on the place and year of their first introductions. For Passer domesticus and Columba livia var. domestica, data on population densities are also provided from several southern African towns. The most speciose groups of introduced species were parrots (Psittaciformes), comprising 33.6% (including Psittacidae: 13.7%; and Psittaculidae: 15.1%); Anatidae: 12.3%; Phasianidae: 11.0%; and Passeriformes: 30.1%. Most avian introductions in sub-Saharan Africa took place in Southern Africa (mainly the Cape Town, Durban and Johannesburg areas) and in Madagascar and the surrounding islands (mostly Mauritius, Reunion and Seychelles). Most introduced species which have developed viable populations originate from the Afrotropical, Oriental and Palearctic regions (altogether 78%), with only 2% from the New World. The proportions among the introduced species which have not established viable populations are quite different: 29% from the New World and only 60% from the Afrotropical, Oriental and Palearctic regions. The main factors affecting successful avian introductions and introduction pathways have been identified. A review of the control measures undertaken in sub-Saharan Africa (mainly in small oceanic islands) is outlined for the following species: Passer domesticus, Acridotheres tristis, Corvus splendens, Pycnonotus jocosus, Foudia madagascariensis, Psittacula krameri and Agapornis roseicollis.

The introduction of alien species may pose an enormous threat to indigenous flora and fauna. Among introduced animals, probably the most destructive to the natural environment are mammals. This is true at least in regard to the Afrotropical Region (sub-Saharan Africa). This review attempts to summarize our knowledge on alien mammals in this region and their impact on indigenous vertebrate fauna. This review includes 56 mammal species, belonging to 20 families, introduced to sub-Saharan Africa over the last 2000 years. Most are representatives of the following orders: Artiodactyla, Carnivora, and Primates. Most species introduced to sub-Saharan Africa originated from the Oriental (n = 20) and Palearctic (n = 19) regions. Two species, Mus musculus and Rattus rattus, were introduced before 1400 (probably as early as 800 AD), while three others were introduced between 1401 and 1700. The first half of the 17th century saw the highest number (n = 10) of introduced species. Between 1651 and 1850, only two species were introduced; in the following 175 years (1851–2025), as many as 24 species were introduced. Ten of the introduced mammal species, namely Sus scrofa, Capra hircus, Rattus rattus, R. norvegicus, Mus musculus, Felis catus, Canis familiaris, Viverricula indica, Urva auropunctata, and Maccaca fuscicularis, have become invasive species. A total of 39 mammal species were relocated (mainly for hunting purposes) within sub-Saharan Africa. Most of them were representatives of the family Bovidae (76.9%). Relocations are not considered introductions. Based on published records of the impacts of alien mammals on the vertebrate fauna of sub-Saharan Africa, the following mechanisms may be distinguished: predation, competition, hybridization, transmission of diseases and parasites, and habitat destruction (grazing, herbivory, browsing). Most vertebrate species (79.4%) were affected through direct predation, predation and habitat destruction (7.1%), or predation and competition (1.4%). Alien mammals have caused habitat destruction for only 10 species (7.1%). Other effects (competition and genetic pollution) were marginal (3.5%). At least 144 vertebrate species, representing 52 families, have been affected by alien mammals in sub-Saharan Africa: 3 amphibians, 23 reptiles, 89 birds, and 29 mammals. As a result of mammal introductions, 65 species in sub-Saharan Africa have become globally extinct, 45 are considered threatened (listed in the RDB), and 31 other species are in decline, although not included in the RDB. Most extinct birds were affected by introduced rats, mice, feral cats, and dogs. In continental Africa, only seven vertebrate species have been negatively affected by alien mammals. All other affected vertebrates occur on islands. An especially high rate of extinction has been recorded in the Mascarene Islands. In comparison with alien birds in sub-Saharan Africa, the number of introduced mammal species is much lower, but their negative impact on vertebrate fauna is significantly greater.

Nest-site competition between invasive and native cavity nesting birds and its implication for conservation

Some alien birds have as severe an impact as the most effectual alien mammals in Europe

Population Studies on different agricultural and other bird species were carried out at Students farm, College farm, Agri biodiversity park, and Agricultural Research Institute farm areas of Professor Jayashankar Telangana State Agricultural University (PJTSAU) Campus in semiarid region of Telangana state covering an area of about 36 Sq.km. for a period of eleven years (2012 to 2023). Population diversity of 92 species of different birds, and their distribution within the university campus farm areas were recorded. Important among them are 9 species namely: Blue rock pigeon (Columba livia), Spotted dove (Streptopelia chinensis), Rose ringed parakeet (Psittacula krameri),Common myna (Acridotheres tristis), House crow (Corvus splendens), House sparrow (Passer domesticus), Baya weaver bird (Ploceus philippinus), White throated munia (Lonchura malabarica), and Peafowl (Pavo cristatus) which depredate experimental field crops among them only few birds such as: Rose ringed parakeets, House crows, House sparrows, Pigeons, Baya weavers, Peafowls and Munias were serious bird pests to major agricultural and horticultural crops. The University farm areas were found to be the most preferred habitat for many of these birds, it could be due to availability of food, breeding, roosting and resting sites in abundance because of more agricultural croplands and agro forestry trees.

Human–wildlife conflicts (HWC) arising from fruit bats eating commercial fruits is a worsening problem worldwide and is epitomized by the Mauritian flying fox (Pteropus niger), a species threatened with extinction yet repeatedly mass-culled since 2015. Non-lethal solutions for dealing with this HWC are needed, which are rooted in the evidence available. In this study, we tracked the movements of 12 flying fox individuals over two years in order to document the animal’s movement ecology, with a view to deriving recommendations to alleviate the ensuing HWC. We found that flying foxes prefer to forage and roost in forested areas located at elevations < 250 m. However, during the fruiting season of commercial trees, the animals tended to roost closer to and forage more often on commercial fruits during the early hours of the night. These findings have several implications for the improvement of commercial fruit protection, which should in turn alleviate HWC, notably through informing management to take into consideration the spatio-temporal expression of flying fox foraging.

Aim: To determine seroprevalence and haematological parameters of some wild and semidomesticated birds naturally infected with avian pox virus (APV). Methods: A total of 160 birds belonging to 12 species were used for the study. Serum samples obtained from these birds were analyzed for antibodies to Avian Pox Virus (APV) using agar gel precipitation test. Natt-Herricks methods and thin blood smear technique were used for the haematological analysis. Results: APV serum antibody positivity was 90%, 100%, 80%, 100%, 70%, 80%, 90%, 70%, 100%, 90%, 80% and 80% for Speckled pigeons, domestic pigeons and Mourning collar dove, Laughing dove, Village weaver, Cut throat fire finch, Cattle egret, Helmeted guinea fowl, Rose-ringed parakeets, African silver billed, Senegal parrots and Red-billed quelea, respectively. The highest PCV of 51.0&plusmn;4.0%, Hb concentration of 16.7 &plusmn; 0.8 g/dl and T.P (5.3 &plusmn; 0.2 g/dl) were obtained from Rose-ringed parakeet, African silver billed and Laughing dove respectively. The mean range values for PCV, Hb, MCV, MCH, MCHC and TP of all the birds in this study were between 28.0 &plusmn; 2.3 to 51.0 &plusmn; 4.0 %, 3.8 &plusmn; 0.4 to 16.4 &plusmn; 0.8 g/dl and 2.07 &plusmn; 2.02 to 5.3 &plusmn; 0.2 g/dl respectively. Also, the mean range values for mean corpuscular volume (MCV),mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) of all the birds were between 78.9 &plusmn; 4.2 to 138.0 &plusmn; 22.3 fl, 28.2 &plusmn; 2.5 to 49.1 &plusmn; 7.9 pg, 78.9 &plusmn; 4.2 to 138.0 &plusmn; 22.3 fl, 28.2 &plusmn; 2.5 to 49.1 &plusmn; 7.9 pg and 31. 6 &plusmn; 1.19 to 37.7 &plusmn; 1.7 g/dl and 31. 6 &plusmn; 1.19 to 37.7 &plusmn; 1.7 g/dl, respectively. Conclusion: Avian pox virus is present in some wild and semi-domesticated birds in Zaria and could spread to commercial poultry. Key words: Seroprevalence, Haematology, Wild birds.

The purpose of this study was to determine reference interval intraocular pressure (IOP) values in 8 different species of companion birds. One hundred and nineteen companion birds (238 eyes) from a captive colony were examined: 21 pigeons (Columba livia; 18%), 17 African grey parrots (Psittacus erithacus; 14%), 22 common mynahs (Acridotheres tristis; 18%), 24 cockatiels (Nymphicus hollandicus; 20%), 12 zebra finches (Taeniopygia guttata; 10%), 9 budgerigars (Melopsittacus undulatus; 8%), 6 domestic canaries (Serinus canaria domestica; 5%), and 8 ring-necked parakeets (Psittacula krameri; 7%). Intraocular pressure was measured by rebound tonometry (TonoVet) avoiding induced, undesired pressure on the head, neck, or eyes. Mean IOP values varied by species. Mean (± SD) IOP values determined for each species were pigeon (5.42 ± 2.06 mm Hg), African grey parrot (4.93 ± 1.91 mm Hg), common mynah (6.22 ± 2.04 mm Hg), cockatiel (5.08 ± 1.76 mm Hg), zebra finch (5.90 ± 2.11 mm Hg), budgerigar (5.88 ± 2.31mm Hg), canary (5.83 ± 1.60 mm Hg), and ring-necked parakeet (6.25 ± 1.75 mm Hg). No statistically significant differences were found in IOP values between right and left eyes for the species studied (P > .22), with the exception of the ring-necked parakeet (P = .001). The results of this study provide representative IOP values measured using rebound tonometry in 8 different species of companion birds.

Flying foxes play keystone ecological roles in plant reproduction. Yet, they face numerous threats, including persecution for eating commercial fruits. This human-wildlife conflict has recently escalated to culling campaigns of a threatened flying fox on Mauritius. Finding non-lethal solutions to this human-wildlife conflict on the island is therefore extremely important. We hypothesized that invasive alien plants may reduce native fruit availability through competition and that weeding alien plants could improve the native foraging habitat quality of flying foxes – in turn, reducing their consumption of commercially important fruits. We compared native fruit production and foraging intensity of the Mauritian flying fox (Pteropus niger) in forests weeded of alien plants a decade previously and adjacent non-weeded forests. Fruits and ejecta were collected weekly during five months under 144 randomly chosen native trees of two canopy species whose fruits are eaten by flying foxes. Intraspecific variations in tree and fruit traits were used to examine flying fox foraging preference. Native fruit production was significantly higher in weeded forests for both tree species, and this was matched by higher flying fox foraging intensity. Flying foxes preferred large trees and fed predominantly on large and ripe fruits. The predominant consumption of ripe fruits emphasizes the importance of flying foxes as seed dispersers. Our results indicate that alien plant invasion substantially reduces native fruit production and that weeded forests provide a much better habitat for flying foxes. Our findings lend support to invasive alien plant control as a management strategy in mitigating such human-wildlife conflicts.

A bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. European Starling (Sturnus vulgaris), Common Myna (Acridotheres tristis) and Red-vented Bulbul (Pycnonotus cafer) have been included on the list of '100 of the World's Worst Invasive Alien Species', a subset of the Global Invasive Species Database. The 'Delivering Alien Invasive Species Inventories for Europe' project has selected Canada Goose (Branta canadensis), Ruddy Duck (Oxyura jamaicensis), Rose-ringed Parakeet (Psittacula krameri) and Sacred Ibis (Threskiornis aethiopicus) as among 100 of the worst invasive species in Europe. For each of these alien bird species, the geographic range (native and introduced range), the introduction pathway, the general impacts and the management methods are presented.

Mass-culling of a threatened island flying fox species failed to increase fruit growers’ profits and revealed gaps to be addressed for effective conservation

Disproportionately large ecological role of a recently mass-culled flying fox in native forests of an oceanic island

Rose-ringed parakeets Psittacula krameri are one of the most widely distributed urban avian invader species present in ~ 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 myna Acridotheres tristis being the species that frequently shared roosts with parakeets. Three tree species were used as roosts, with the Natal mahogany Trichilia emetica and the giant palm Raphia 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.

Because of its use as a nuclear materials production area, the 800-km 2 sagebrush steppe of the Columbia River Plain in Washington State has functioned as a quasi-natural area protected from livestock grazing and agricultural development since 1944. Alien vegetation and animals have invaded the eastern Washington region in the past century and are currently represented in the Columbia River Plain. Investigations were undertaken to evaluate the distribution of alien species, particularly vegetation, and their relationships to other flora and fauna in this region. Recently disturbed areas were dominated by the alien annuals Russian thistle Salsola kali, tumble mustard Sisymbrium altissimum, prickly lettuce Lactuca serriola, and bur ragweed Ambrosia acanthicarpa. Old-field habitats were composed almost entirely of the alien annual cheatgrass Bromus tectorum. Alien vegetation also comprised a portion of the flora in habitats that had not been disturbed or grazed by cattle in the past. Cheatgrass and spring whitlow-grass Draba verna were able to set seed in undisturbed habitats, whereas Russian thistle and tumble mustard seldom did. These two species continue as components of undisturbed habitat primarily through seed dispersal from disturbed sites. Old-field habitats support a depauperate fauna compared to undisturbed sagebrush steppe vegetation. Shrub-nesting birds such as the sage sparrow Amphispiza belli were absent from old fields, and even ground-nesting species were found in abnormally low densities. Old fields supported relatively few mammal species, in part as a result of poor food supplies. Alien birds, the rock dove Columba livia and the European starling Sturnus vulgaris, visited undisturbed habitat, but did not nest there. No alien mammals were found in undisturbed sagebrush steppe vegetation; the only alien mammals found in the area, the house mouse Mus musculus and Norway rat Rattus norvegicus, being limited to riparian areas and the vicinity of buildings. Alien taxa are likely to remain a component of any quasi-natural area in the sagebrush steppe ecoregion. Human disturbance need not be spatially extensive to maintain alien plants within undisturbed communities. Successional patterns after land disturbance produce conditions unfavorable for native fauna, but have not enhanced the distribution of alien fauna.