Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2034040
Aenea Saanya, A. Massawe, R. Makundi
Threats to ecosystems are ever increasing from different drivers mostly being linked to anthropogenic activities. This has brought about various measures to restore/protect the wildlife in these areas. Considering the background of most protected areas in East Africa, small mammals have been given least attention, compared with large mammals, although they play a fundamental role in maintaining ecosystem health. It is therefore necessary to understand how small mammals are distributed in any given ecosystem as a baseline information to enable holistic and informed management. We investigated the diversity and distribution of small mammals in the Selous ecosystem, Tanzania. Two methods were used; Capture Mark Recapture (CMR) using grids of 70 m × 70 m and random placement of havahart traps in the selected habitats. Between July 2018 and June 2020, a total of 887 individuals belonging to 20 species were captured in 28 224 trap nights with 3% trap success. The small mammal species captured consisted of rodents (91.8%), Macroscelidea (3.9%), Carnivores (2.4%) Eulipotyphla (1.6%), and Primates (0.3%). Acomys ngurui (36%) and Aethomys chrysophilus (17%) were the most captured species, whereas Atilax paludinosus (0.23%), Helogale pervula (0.23%), Rattus rattus (0.23%) and Galerella sanguinea (0.11%) were the least contributing species. Acomys ngurui and Lemniscomys rosalia were the most distributed species occurring in all four habitats, whereas Cricetomys ansorgei, Rattus rattus, Mungos mungo and Genetta genetta had low occurrence. Grammomys selousi is reported for the first time in the northern part of the Rufiji River. Acomys ngurui abundance differed significantly (χ2 = 12, df = 3, p = 0.007) between the four habitats being higher in the seasonal riverine forest and across seasons (χ2 = 6, df = 2, p = 0.049), with more individuals occurring in the wet season. The Sable Forest habitat had the highest species diversity (H′ = 2.065) and the lowest diversity (H′ = 1.506) was recorded in perennial riverine forest/thickets. The highest species diversity (H′ = 1.65) was recorded in the dry season and the lowest diversity in the wet season (H′ = 1.445). Most small mammals were associated with seasonal riverine forest than other habitats. Overall, the results from this study show that, the park is rich in small mammal fauna. Therefore, considerations in updating the General Management Plan (GMP) and other plans to include the small mammals in the park management actions is recommended.
{"title":"Small Mammal Species Diversity and Distribution in the Selous Ecosystem, Tanzania","authors":"Aenea Saanya, A. Massawe, R. Makundi","doi":"10.1080/15627020.2022.2034040","DOIUrl":"https://doi.org/10.1080/15627020.2022.2034040","url":null,"abstract":"Threats to ecosystems are ever increasing from different drivers mostly being linked to anthropogenic activities. This has brought about various measures to restore/protect the wildlife in these areas. Considering the background of most protected areas in East Africa, small mammals have been given least attention, compared with large mammals, although they play a fundamental role in maintaining ecosystem health. It is therefore necessary to understand how small mammals are distributed in any given ecosystem as a baseline information to enable holistic and informed management. We investigated the diversity and distribution of small mammals in the Selous ecosystem, Tanzania. Two methods were used; Capture Mark Recapture (CMR) using grids of 70 m × 70 m and random placement of havahart traps in the selected habitats. Between July 2018 and June 2020, a total of 887 individuals belonging to 20 species were captured in 28 224 trap nights with 3% trap success. The small mammal species captured consisted of rodents (91.8%), Macroscelidea (3.9%), Carnivores (2.4%) Eulipotyphla (1.6%), and Primates (0.3%). Acomys ngurui (36%) and Aethomys chrysophilus (17%) were the most captured species, whereas Atilax paludinosus (0.23%), Helogale pervula (0.23%), Rattus rattus (0.23%) and Galerella sanguinea (0.11%) were the least contributing species. Acomys ngurui and Lemniscomys rosalia were the most distributed species occurring in all four habitats, whereas Cricetomys ansorgei, Rattus rattus, Mungos mungo and Genetta genetta had low occurrence. Grammomys selousi is reported for the first time in the northern part of the Rufiji River. Acomys ngurui abundance differed significantly (χ2 = 12, df = 3, p = 0.007) between the four habitats being higher in the seasonal riverine forest and across seasons (χ2 = 6, df = 2, p = 0.049), with more individuals occurring in the wet season. The Sable Forest habitat had the highest species diversity (H′ = 2.065) and the lowest diversity (H′ = 1.506) was recorded in perennial riverine forest/thickets. The highest species diversity (H′ = 1.65) was recorded in the dry season and the lowest diversity in the wet season (H′ = 1.445). Most small mammals were associated with seasonal riverine forest than other habitats. Overall, the results from this study show that, the park is rich in small mammal fauna. Therefore, considerations in updating the General Management Plan (GMP) and other plans to include the small mammals in the park management actions is recommended.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44028475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2051737
Eshetu Esatu, Abebayehu Desalegn Hailemariam
The common bushbuck (Tragelaphus scriptus decula) is a widely distributed antelope species in Africa that utilises a variety of habitat types. A study was conducted on the population status and diurnal activity pattern of T. s. decula in Maze National Park, Ethiopia, from January to July 2020 during the wet and dry seasons. Data were collected using randomly sampled blocks covering a total area of 34 km2. The data were analysed using descriptive statistics and compared with Chi-square and one-way ANOVA tests. The average population size throughout both the wet and the dry season was 21 ± 8, of which 10.5 ± 3.5, 4.0 ± 2.0 and 6.5 ± 2.5 were adults, subadults and juveniles. There was a significant difference ( χ2 = 3.4, df = 4, p < 0.05) in the T. s. decula population between the two seasons. The sex ratio of adult males to adult females was 0.56:1 and 0.75:1 in the dry and the wet seasons, respectively, indicating a population predominated by females. The mean group size was x̄ = 2.16 and 2.00 for the dry and wet seasons, respectively. The riverine forest had the greatest number of individuals and hence highest density and population distribution per square kilometre; however, distribution between the habitats did not vary significantly (F = 2.71, df = 4, p = 0.16). The overall density of the population was very low in the sampled blocks, with the population density not exceeding one per 1.7 km2. The dominant activity pattern of T. s. decula was feeding followed by resting and running/fighting. Even though its population was predominantly female, a good indicator for future breeding success, the low numbers and density of common T. s. decula due to the high impact of illegal hunting and predation, especially of subadults, indicates a vulnerable population requiring enhanced conservation efforts.
普通羚羊(Tragelaphus scriptus decula)是非洲广泛分布的羚羊物种,利用各种栖息地类型。在埃塞俄比亚Maze国家公园,对2020年1 - 7月旱季和湿季的地盲蝽(T. s. decula)种群状况和日活动模式进行了研究。数据收集采用随机抽样的块,覆盖总面积为34平方公里。资料分析采用描述性统计,比较采用卡方检验和单因素方差分析。干湿季节平均种群数为21±8只,其中成虫、亚成虫和幼虫分别为10.5±3.5、4.0±2.0和6.5±2.5只。两季间小蠹蛾种群数量差异有统计学意义(χ2 = 3.4, df = 4, p < 0.05)。干季和湿季成虫雌雄性别比分别为0.56:1和0.75:1,以雌虫为主。干季和湿季平均种群大小分别为x′= 2.16和2.00。河流森林的个体数量最多,因此每平方公里的密度和种群分布最高;不同生境间的分布差异不显著(F = 2.71, df = 4, p = 0.16)。样本区总体人口密度很低,每1.7 km2人口密度不超过1人。斑胸衣绦虫的主要活动模式是进食后休息,再跑/斗。尽管它的种群以雌性为主,这是未来繁殖成功的一个很好的指标,但由于非法狩猎和捕食的严重影响,特别是对亚成虫的影响,普通斑胸虫的数量和密度都很低,这表明它是一个脆弱的种群,需要加强保护工作。
{"title":"Preliminary Assessment of the Population Status and Diurnal Activity Pattern of Common Bushbuck (Tragelaphus scriptus decula Rüppell, 1835) in Maze National Park, Ethiopia","authors":"Eshetu Esatu, Abebayehu Desalegn Hailemariam","doi":"10.1080/15627020.2022.2051737","DOIUrl":"https://doi.org/10.1080/15627020.2022.2051737","url":null,"abstract":"The common bushbuck (Tragelaphus scriptus decula) is a widely distributed antelope species in Africa that utilises a variety of habitat types. A study was conducted on the population status and diurnal activity pattern of T. s. decula in Maze National Park, Ethiopia, from January to July 2020 during the wet and dry seasons. Data were collected using randomly sampled blocks covering a total area of 34 km2. The data were analysed using descriptive statistics and compared with Chi-square and one-way ANOVA tests. The average population size throughout both the wet and the dry season was 21 ± 8, of which 10.5 ± 3.5, 4.0 ± 2.0 and 6.5 ± 2.5 were adults, subadults and juveniles. There was a significant difference ( χ2 = 3.4, df = 4, p < 0.05) in the T. s. decula population between the two seasons. The sex ratio of adult males to adult females was 0.56:1 and 0.75:1 in the dry and the wet seasons, respectively, indicating a population predominated by females. The mean group size was x̄ = 2.16 and 2.00 for the dry and wet seasons, respectively. The riverine forest had the greatest number of individuals and hence highest density and population distribution per square kilometre; however, distribution between the habitats did not vary significantly (F = 2.71, df = 4, p = 0.16). The overall density of the population was very low in the sampled blocks, with the population density not exceeding one per 1.7 km2. The dominant activity pattern of T. s. decula was feeding followed by resting and running/fighting. Even though its population was predominantly female, a good indicator for future breeding success, the low numbers and density of common T. s. decula due to the high impact of illegal hunting and predation, especially of subadults, indicates a vulnerable population requiring enhanced conservation efforts.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44066785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2021.2016073
N. Mashele, Lindy J. Thompson, C. Downs
Raptors have crucial functions, both ecologically and as environmental indicators. Currently, many raptor species worldwide are threatened, and the potential loss of functional groups will yield dire consequences. We identified the trends and causes of raptor admissions to the Moholoholo Wildlife Rehabilitation Centre, Limpopo province, South Africa, using information from the case files of 629 individual raptors from 44 species that were admitted between 1996 (month unspecified) and February 2018. The most frequently admitted raptor species were the Western Barn Owl Tyto alba (n = 130), Spotted Eagle-owl Bubo africanus (n = 81) and White-backed Vulture Gyps africanus (n = 53). Raptors came from as far away as Ghana, although most of the birds were from Limpopo and Mpumalanga provinces, South Africa. In 48% of cases (n = 304), the causes of injuries were not documented. Of the 252 cases in which the causes of injury were recorded, the most frequent causes of injury (for all raptor species combined) were poisoning (23%, n = 59), followed by motor vehicle collisions (17%, n = 43), falls from nests (10%, n = 25), and collisions with fences (8%, n = 20). For the 516 individuals for which the outcome was known, the most common outcome was ‘release’ (37%, n = 193). Our results highlight the impact of poisoning on raptors and underpin the need for increased public education about the ecological and cultural importance of raptors, and the threats that raptors face.
{"title":"Trends in the Admission of Raptors to the Moholoholo Wildlife Rehabilitation Centre, Limpopo Province, South Africa","authors":"N. Mashele, Lindy J. Thompson, C. Downs","doi":"10.1080/15627020.2021.2016073","DOIUrl":"https://doi.org/10.1080/15627020.2021.2016073","url":null,"abstract":"Raptors have crucial functions, both ecologically and as environmental indicators. Currently, many raptor species worldwide are threatened, and the potential loss of functional groups will yield dire consequences. We identified the trends and causes of raptor admissions to the Moholoholo Wildlife Rehabilitation Centre, Limpopo province, South Africa, using information from the case files of 629 individual raptors from 44 species that were admitted between 1996 (month unspecified) and February 2018. The most frequently admitted raptor species were the Western Barn Owl Tyto alba (n = 130), Spotted Eagle-owl Bubo africanus (n = 81) and White-backed Vulture Gyps africanus (n = 53). Raptors came from as far away as Ghana, although most of the birds were from Limpopo and Mpumalanga provinces, South Africa. In 48% of cases (n = 304), the causes of injuries were not documented. Of the 252 cases in which the causes of injury were recorded, the most frequent causes of injury (for all raptor species combined) were poisoning (23%, n = 59), followed by motor vehicle collisions (17%, n = 43), falls from nests (10%, n = 25), and collisions with fences (8%, n = 20). For the 516 individuals for which the outcome was known, the most common outcome was ‘release’ (37%, n = 193). Our results highlight the impact of poisoning on raptors and underpin the need for increased public education about the ecological and cultural importance of raptors, and the threats that raptors face.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47100577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2057818
Alexander Edward Botha, A. Bruns, A. le Roux
An animal's ability to traverse a landscape and utilise available resources is vital for its survival. The movement patterns of an animal provide insight into space use, activity patterns and ecological requirements that are imperative for successful farming and wildlife management practices. Home ranges are often used as a measurement of space use, which provides a quantitative value of an animal's movement patterns in relation to various biological factors. A factor that is often overlooked in the analysis of movement patterns is the effect of moon phase, despite its known impact on the activity and hunting success of nocturnal predators. We live-trapped, radio-collared and monitored five black-backed jackals (Canis mesomelas) in the Golden Gate Highlands National Park, South Africa, between 2018 and 2019 to determine the impact of various environmental factors on movement patterns. Annual home ranges varied between individuals, were larger in subadults and overlapped between three jackals. Space use and travel velocity suggested a crepuscular activity pattern with a reliance on nocturnal activity and limited diurnal activity. Individual space use suggested variation between moon phases, although overall variation was negligible. Jackals travelled farther during new moon, compared with full moon, with the most notable difference between 23:00 and 04:00. Our results suggest that jackal behaviour does not align with the predation risk hypothesis. Space use and travel velocities varied between seasons, possibly because of differences in activity during mating and pupping periods. Our study confirms the flexibility in jackal space use and suggests a possible relationship with moon phase. To properly understand movement patterns at an individual and population level, we encourage additional research about jackals and various environmental factors via multidisciplinary collaborations.
{"title":"The Spatial Ecology of Black-Backed Jackals (Canis mesomelas) in a Protected Mountainous Grassland Area","authors":"Alexander Edward Botha, A. Bruns, A. le Roux","doi":"10.1080/15627020.2022.2057818","DOIUrl":"https://doi.org/10.1080/15627020.2022.2057818","url":null,"abstract":"An animal's ability to traverse a landscape and utilise available resources is vital for its survival. The movement patterns of an animal provide insight into space use, activity patterns and ecological requirements that are imperative for successful farming and wildlife management practices. Home ranges are often used as a measurement of space use, which provides a quantitative value of an animal's movement patterns in relation to various biological factors. A factor that is often overlooked in the analysis of movement patterns is the effect of moon phase, despite its known impact on the activity and hunting success of nocturnal predators. We live-trapped, radio-collared and monitored five black-backed jackals (Canis mesomelas) in the Golden Gate Highlands National Park, South Africa, between 2018 and 2019 to determine the impact of various environmental factors on movement patterns. Annual home ranges varied between individuals, were larger in subadults and overlapped between three jackals. Space use and travel velocity suggested a crepuscular activity pattern with a reliance on nocturnal activity and limited diurnal activity. Individual space use suggested variation between moon phases, although overall variation was negligible. Jackals travelled farther during new moon, compared with full moon, with the most notable difference between 23:00 and 04:00. Our results suggest that jackal behaviour does not align with the predation risk hypothesis. Space use and travel velocities varied between seasons, possibly because of differences in activity during mating and pupping periods. Our study confirms the flexibility in jackal space use and suggests a possible relationship with moon phase. To properly understand movement patterns at an individual and population level, we encourage additional research about jackals and various environmental factors via multidisciplinary collaborations.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44121322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2047104
Jessica Seath, C. Shackleton
Invasive alien species are regarded as the second greatest threat to biodiversity globally. Yet, at a local scale their effects may vary, underlying the requirement for more local-scale studies across taxa and settings. Here we consider the effects of an alien invasive tree (Acacia dealbata, 5–8 m tall) on avifaunal numbers, richness and diversity in A. dealbata patches of three sizes relative to adjacent montane grasslands. Analysis of historical aerial photographs showed that A. dealbata first occurred in the area in the late 1930s/early 1940s and has continued to spread, despite some efforts by the landowner to keep it in check. It now covers approximately 11% of the site. This has provided habitat for a number of bird species more characteristic of wooded vegetation types. The number, richness and diversity of birds were greater in A. dealbata patches than the adjacent grasslands of equivalent size. These measures increased with increasing patch size, but more rapidly for A. dealbata patches than grassland ones. Only six of the 48 species of birds recorded were common between the two vegetation types. The most common feeding guild in the A. dealbata patches was insectivores, whereas in the grasslands it was omnivores. Although the invasion of A. dealbata has added to the habitat diversity of the area, thereby facilitating increased avifaunal diversity, if it continues to spread, then the populations and perhaps richness of grassland birds are likely to be negatively affected.
{"title":"Comparative Avifaunal Richness and Diversity in Invasive Acacia dealbata Patches and Adjacent Montane Grasslands","authors":"Jessica Seath, C. Shackleton","doi":"10.1080/15627020.2022.2047104","DOIUrl":"https://doi.org/10.1080/15627020.2022.2047104","url":null,"abstract":"Invasive alien species are regarded as the second greatest threat to biodiversity globally. Yet, at a local scale their effects may vary, underlying the requirement for more local-scale studies across taxa and settings. Here we consider the effects of an alien invasive tree (Acacia dealbata, 5–8 m tall) on avifaunal numbers, richness and diversity in A. dealbata patches of three sizes relative to adjacent montane grasslands. Analysis of historical aerial photographs showed that A. dealbata first occurred in the area in the late 1930s/early 1940s and has continued to spread, despite some efforts by the landowner to keep it in check. It now covers approximately 11% of the site. This has provided habitat for a number of bird species more characteristic of wooded vegetation types. The number, richness and diversity of birds were greater in A. dealbata patches than the adjacent grasslands of equivalent size. These measures increased with increasing patch size, but more rapidly for A. dealbata patches than grassland ones. Only six of the 48 species of birds recorded were common between the two vegetation types. The most common feeding guild in the A. dealbata patches was insectivores, whereas in the grasslands it was omnivores. Although the invasion of A. dealbata has added to the habitat diversity of the area, thereby facilitating increased avifaunal diversity, if it continues to spread, then the populations and perhaps richness of grassland birds are likely to be negatively affected.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49023643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2046155
S. Penny, M. Withey, Rachel L. White, D. Scott, Lynne M. MacTavish, A. Pernetta
In many social species physical attributes correlate with dominance rankings and influence the outcomes of dyadic interactions. We investigated the processes that affect white rhinoceros' social behaviour in response to a reduction in horn size asymmetries within a group of subadult individuals. We monitored agonistic social interactions and the orderliness of social rankings between six free ranging rhinoceroses before and after they underwent a second dehorning procedure. We used a modified version of Landau's h′ to measure linearity, a score of steepness to measure power asymmetry, and a measure of triangle transitivity to assess relationships in the presence of null dyads. Agonistic social interactions were significantly greater after the monitored dehorning procedure. Hierarchies possessed significant steepness and transitivity prior to the procedure, but not after. Linearity was non-significant and rank order did not correspond with changes in horn size or age. Our results provide the first evidence of a dominance hierarchy among free-ranging white rhinoceroses outside of reproductive competition, but indicate that physical attributes alone do not explain social rankings. Rhinoceroses transitioned to a more egalitarian dominance structure than a despotic one after the procedure, but dominance ranks were only weakly differentiated within the group. Although a reduction in horn asymmetries may increase agonistic behaviours via psychosocial or behavioural changes, drier climatic conditions cannot be ruled out as the causative factor and because the subadult group stayed together, rather than dispersing, any increased fitness costs are likely to be minimal and outweighed by the benefits of group membership.
{"title":"Changes in Social Dominance in a Group of Subadult White Rhinoceroses (Ceratotherium simum) after Dehorning","authors":"S. Penny, M. Withey, Rachel L. White, D. Scott, Lynne M. MacTavish, A. Pernetta","doi":"10.1080/15627020.2022.2046155","DOIUrl":"https://doi.org/10.1080/15627020.2022.2046155","url":null,"abstract":"In many social species physical attributes correlate with dominance rankings and influence the outcomes of dyadic interactions. We investigated the processes that affect white rhinoceros' social behaviour in response to a reduction in horn size asymmetries within a group of subadult individuals. We monitored agonistic social interactions and the orderliness of social rankings between six free ranging rhinoceroses before and after they underwent a second dehorning procedure. We used a modified version of Landau's h′ to measure linearity, a score of steepness to measure power asymmetry, and a measure of triangle transitivity to assess relationships in the presence of null dyads. Agonistic social interactions were significantly greater after the monitored dehorning procedure. Hierarchies possessed significant steepness and transitivity prior to the procedure, but not after. Linearity was non-significant and rank order did not correspond with changes in horn size or age. Our results provide the first evidence of a dominance hierarchy among free-ranging white rhinoceroses outside of reproductive competition, but indicate that physical attributes alone do not explain social rankings. Rhinoceroses transitioned to a more egalitarian dominance structure than a despotic one after the procedure, but dominance ranks were only weakly differentiated within the group. Although a reduction in horn asymmetries may increase agonistic behaviours via psychosocial or behavioural changes, drier climatic conditions cannot be ruled out as the causative factor and because the subadult group stayed together, rather than dispersing, any increased fitness costs are likely to be minimal and outweighed by the benefits of group membership.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45927146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2053883
G. Kerley, Sophie Monsarrat
Human activities have affected animals’ behaviour, distribution and population structure and this effect is predicted to increase in the future. Considerable effort is therefore being focussed on understanding and predicting such future changes in response to anthropogenic pressures, this to better conserve and restore populations and species. However, there is a risk that scientists and practitioners fail to recognise the extent of past human effects on biodiversity and use the situation they are familiar with as a baseline and a measure against which to assess current or future biodiversity changes. This failure to recognise past changes is known as the shifting baseline syndrome (Pauly 1995). We propose that when models (descriptive, quantitative or conceptual) describing niche features, such as distribution, habitat use, dietary resources or behaviour, are developed using data collected in a system (communities, species or populations) that has already undergone shifted baselines, such models should be referred to as ‘shifted models’. Here we define such shifted models and demonstrate associated shortcomings, focusing on the particular example of shifted environmental niche models in a recently published study on African elephants Loxodonta africana (Dejene et al. 2021).
人类活动影响了动物的行为、分布和种群结构,预计这种影响将在未来增加。因此,相当多的努力集中在了解和预测这种未来变化以应对人为压力,以便更好地保护和恢复种群和物种。然而,有一种风险是科学家和实践者没有认识到过去人类对生物多样性影响的程度,并且没有使用他们所熟悉的情况作为基线和衡量来评估当前或未来的生物多样性变化。这种无法识别过去变化的现象被称为基线转移综合征(Pauly 1995)。我们建议,当描述生态位特征(如分布、栖息地利用、饮食资源或行为)的模型(描述性、定量或概念性)是利用一个系统(群落、物种或种群)中收集的数据开发的,这些数据已经经历了基线的转移,这样的模型应该被称为“转移模型”。在这里,我们定义了这种转移模型,并展示了相关的缺点,重点关注最近发表的一项关于非洲象Loxodonta africana的研究中转移环境生态位模型的具体例子(Dejene et al. 2021)。
{"title":"Shifted Models Cannot be Used for Predicting Responses of Biodiversity to Global Change: The African Elephant as an Example","authors":"G. Kerley, Sophie Monsarrat","doi":"10.1080/15627020.2022.2053883","DOIUrl":"https://doi.org/10.1080/15627020.2022.2053883","url":null,"abstract":"Human activities have affected animals’ behaviour, distribution and population structure and this effect is predicted to increase in the future. Considerable effort is therefore being focussed on understanding and predicting such future changes in response to anthropogenic pressures, this to better conserve and restore populations and species. However, there is a risk that scientists and practitioners fail to recognise the extent of past human effects on biodiversity and use the situation they are familiar with as a baseline and a measure against which to assess current or future biodiversity changes. This failure to recognise past changes is known as the shifting baseline syndrome (Pauly 1995). We propose that when models (descriptive, quantitative or conceptual) describing niche features, such as distribution, habitat use, dietary resources or behaviour, are developed using data collected in a system (communities, species or populations) that has already undergone shifted baselines, such models should be referred to as ‘shifted models’. Here we define such shifted models and demonstrate associated shortcomings, focusing on the particular example of shifted environmental niche models in a recently published study on African elephants Loxodonta africana (Dejene et al. 2021).","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47701922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2035254
R. Foster, A. Childs, B. Mann, W. Potts
The South African spearfishery targets a variety of data-deficient species, which are consequently poorly managed. This study aimed to describe the age and growth of one of these species, the Cape knifejaw, Oplegnathus conwayi, which is endemic to the southern and eastern coasts of South Africa. Monthly biological samples were collected through research spearfishing (n = 170) and augmented by recreational spearfishers' catches (n = 135). The results indicated that the O. conwayi population sex ratio was skewed towards males (1M:0.6F). The length- and age-frequency distributions were similar between sexes. Oplegnathus conwayi is a relatively slow-growing species, with a maximum-recorded age of 27 years. No significant differences were observed between male and female growth, with the overall population growth curve being best described as L(t) = 697.15(1 – e–0.06(t–6.30)). The slow growth observed in this species is characteristic of a species that is vulnerable to overexploitation, and accordingly a precautionary approach to future management is recommended.
{"title":"Age and Growth of the Cape Knifejaw Oplegnathus conwayi, an Endemic South African Teleost","authors":"R. Foster, A. Childs, B. Mann, W. Potts","doi":"10.1080/15627020.2022.2035254","DOIUrl":"https://doi.org/10.1080/15627020.2022.2035254","url":null,"abstract":"The South African spearfishery targets a variety of data-deficient species, which are consequently poorly managed. This study aimed to describe the age and growth of one of these species, the Cape knifejaw, Oplegnathus conwayi, which is endemic to the southern and eastern coasts of South Africa. Monthly biological samples were collected through research spearfishing (n = 170) and augmented by recreational spearfishers' catches (n = 135). The results indicated that the O. conwayi population sex ratio was skewed towards males (1M:0.6F). The length- and age-frequency distributions were similar between sexes. Oplegnathus conwayi is a relatively slow-growing species, with a maximum-recorded age of 27 years. No significant differences were observed between male and female growth, with the overall population growth curve being best described as L(t) = 697.15(1 – e–0.06(t–6.30)). The slow growth observed in this species is characteristic of a species that is vulnerable to overexploitation, and accordingly a precautionary approach to future management is recommended.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44849823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/15627020.2022.2063424
A. McKechnie, N. Mzilikazi, D. Levesque, S. Welman
{"title":"In Memory of Barry Gordon Lovegrove","authors":"A. McKechnie, N. Mzilikazi, D. Levesque, S. Welman","doi":"10.1080/15627020.2022.2063424","DOIUrl":"https://doi.org/10.1080/15627020.2022.2063424","url":null,"abstract":"","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47635640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-02DOI: 10.1080/15627020.2021.2000341
J. Gane, C. Downs, Benjamin Harris, Mark Brown
Increasing beach sediment loss from erosion and high levels of crab Ocypode spp. predation are threatening turtle nests and nesting habitat. The 900 m long beach on Cousine Island, Seychelles, supports a nesting population of approximately 70–130 hawksbill turtle Eretmochelys imbricata nests each season. Seasonal and storm-related erosion and accretion cycles on Cousine Island have the potential of destroying 50% or more of all turtle egg clutches on the island in a single nesting season. Observed crab predation rates had reached 90–100% in preferred nesting beach zones in previous years. This has resulted in intensive management measures to minimise turtle egg and nest losses. We investigated the distribution and population density of ghost crabs and the morphology of the beach across the different beach area zones and across the turtle-nesting season during 2014–2015. Crab burrow numbers varied between beach zone areas and across the season and were highest on the backshore. Crab density correlated negatively with available beach area, and we found that crab density increased in the presence of turtle nests. When examining beach dynamics, we found them to be cyclical and found the nesting beach prone to higher levels of erosion than accretion with significant changes in beach width throughout the season. The mean vertical beach elevation drop on Cousine Island was higher than what hawksbill turtles have been reported to prefer. We suggest the continuation of beach elevation monitoring and management to use the beach morphology data to assist with hawksbill turtle nest translocations to minimise nest losses and maximise hatchling recruitment success.
{"title":"Beach Profiling and Ghost Crab Densities on a Hawksbill Turtle Nesting Beach in the Seychelles","authors":"J. Gane, C. Downs, Benjamin Harris, Mark Brown","doi":"10.1080/15627020.2021.2000341","DOIUrl":"https://doi.org/10.1080/15627020.2021.2000341","url":null,"abstract":"Increasing beach sediment loss from erosion and high levels of crab Ocypode spp. predation are threatening turtle nests and nesting habitat. The 900 m long beach on Cousine Island, Seychelles, supports a nesting population of approximately 70–130 hawksbill turtle Eretmochelys imbricata nests each season. Seasonal and storm-related erosion and accretion cycles on Cousine Island have the potential of destroying 50% or more of all turtle egg clutches on the island in a single nesting season. Observed crab predation rates had reached 90–100% in preferred nesting beach zones in previous years. This has resulted in intensive management measures to minimise turtle egg and nest losses. We investigated the distribution and population density of ghost crabs and the morphology of the beach across the different beach area zones and across the turtle-nesting season during 2014–2015. Crab burrow numbers varied between beach zone areas and across the season and were highest on the backshore. Crab density correlated negatively with available beach area, and we found that crab density increased in the presence of turtle nests. When examining beach dynamics, we found them to be cyclical and found the nesting beach prone to higher levels of erosion than accretion with significant changes in beach width throughout the season. The mean vertical beach elevation drop on Cousine Island was higher than what hawksbill turtles have been reported to prefer. We suggest the continuation of beach elevation monitoring and management to use the beach morphology data to assist with hawksbill turtle nest translocations to minimise nest losses and maximise hatchling recruitment success.","PeriodicalId":55548,"journal":{"name":"African Zoology","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41749011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}