共查询到20条相似文献,搜索用时 15 毫秒
1.
Suzanne K. Frost 《Ostrich》2013,84(3-4):111-116
Frost, S.K. 1990. Notes on the breeding behaviour of Marico and Pallid Flycatchers in the central Transvaal, South Africa. Ostrich 61:111-116. The breeding behaviour of Marico and Pallid Flycatchers (Melaenornis mariquensis and M. pallidus) was studied at the Nylsvley Nature Reserve, South Africa, between September 1980 and January 1981. The flycatchers are morphologically similar but occur in different although sometimes adjacent woodlands. The two species do not differ in their breeding seasons, nor in their clutch sizes. The incubation period, previously unrecorded for Pallid Flycatchers, is 14 days and the fledging period 17 days. Marico Flycatchers fed their chicks more frequently than Pallid Flycatchers and helpers were observed at two Marico Flycatcher nests. 相似文献
2.
E. A. Kukavskaya L. V. Buryak O. P. Kalenskaya D. S. Zarubin 《Contemporary Problems of Ecology》2017,10(1):62-70
Ground fuel loads and structure in dark-coniferous forests with the dominance of Siberian pine have been studied in the Central Siberian State Nature Biosphere Reserve located in the central-taiga zone of Central Siberia. The impacts of surface fires of various forms and severity on the living ground cover are examined. It is found that fires of low to moderate severity reduce ground fuel loads from 35–49 t/ha to 26–28 t/ha, while fires of moderate to high severity reduce them to 17–18 t/ha. Consumption of down woody debris varies from 3 to 29 t/ha, depending on the prefire fuel characteristics and fire form and severity. Steady fires spreading with the fire danger index PV-1 of 3919 ± 482 result in carbon emissions of 14.0 tC/ha from fires of low to moderate severity and 24.6 tC/ha from fires of moderate to high severity. The lowest carbon emissions (10.1 tC/ha) are noted for fast-moving fires spreading with PV-1 of 1167 ± 386. 相似文献
3.
Major R. C. Bolster M.B.O.U 《Ostrich》2013,84(1):15-20
Skead, D. M. 1974. Habitats and feeding preferences of birds on the S.A. Lombard Nature Reserve, Transvaal. Ostrich 45:15-21. The topography, climate and habitats of the S.A. Lombard Nature Reserve are described. The status of the 183 species recorded while the author was resident on the reserve, July 1964 to June 1967, was arranged into the various habitat types. It was found that 25% were residents while 65% of the residents occurred in the “Indifferent” category. Birds with a mixed diet predominated, 48,9%, while insect-eaters rated second, 35,8%. 相似文献
4.
Polystoma claudecombesi is described as a new species of the Polystomatidae (Monogenea) parasitic in the urinary bladder of the anuran host Rana angolensis. This parasite was collected at three localities in South Africa, namely Vernon Crookes Nature Reserve in Natal province,
Witsieshoek Mountain Resort in the north-eastern Orange Free State and Bovenste Oog in the province of Transvaal. It is the
largest African polystome described to date. Prevalence at Vernon Crookes Nature Reserve was 4.0% and 2.7% in two successive
years, with a mean intensity of 1.0 (n=25 and 36, respectively). One of the two R. angolensis from Witsieshoek was infected with 5 parasites. The diversity and distribution of southern African polystomes is also discussed. 相似文献
5.
Paul Ferrar 《Oecologia》1982,52(1):139-146
Summary Cellulose toilet roll baits were exposed in three different subhabitats at Nylsvley Reserve, northern Transvaal, and respective attacks by up to eight species of termites are described and illustrated. In broad-leaved savanna attack was principally by Microcerotermes, a slow feeder that attacked rolls throughout the year, finding about half the rolls exposed each season. In Acacia savanna attack was largely by Microtermes, a fast feeder active only at wetter times of year. In open, grassy areas there was relatively little attack, except sporadically by Macrotermes which consumed whole rolls within a day or two. Bush-fires delayed initial attack on rolls, perhaps because reduced surface litter gave less protection to soil. The amount of each roll eaten during the trials is shown in histograms; it was consistently greater in Acacia than in broad-leaved savanna. The soil-feeding termites Aganotermes and Promirotermes were attracted during the wet season to the undersides of rolls, perhaps as a source of organic-rich soil (or possibly of water). 相似文献
6.
《African Journal of Aquatic Science》2013,38(1):197-201
In late August 1998, a mechanical malfunction at the Nylstroom Sewage Treatment Works resulted in a massive quantity of untreated sewage flowing into the Klein Nyl River. Simultaneously, 5km upstream, a poly-aromatic hydrocarbon poison was simultaneously leaked into the same river from a 25 litre canister. These spills threatened the Nylsvley Nature Reserve, a newly acclaimed RAMSAR site, situated about 20km downstream of Nylstroom. The Limnological team of the Department of Zoology, University of the North, was asked to assist with the assessment of the effect of these spills, which resulted in a massive fish kill. A monitoring program was implemented in early September 1998 to assess the effect of these spills on the water quality of the receiving water body. The implications of the altered water quality on the aquatic biota are discussed. 相似文献
7.
Spatial and temporal variability in fire occurrence within the Las Bayas Forestry Reserve, Durango, Mexico 总被引:2,自引:0,他引:2
Patterns of fire occurrence within the Las Bayas Forestry Reserve, Mexico are analyzed in relation to variability in climate, topography, and human land-use. Significantly more fires with shorter fire return intervals occurred from 1900 to 1950 than from 1950 to 2001. However, the frequency of widespread fire years (25% filter) was unchanged over time, as widespread fires were synchronized by climatic extremes. Widespread fire years occurred during dry years that lagged wet years. Widespread fire years lagged the negative El Niño phase (wet winters) of the Southern Oscillation by 1 year, but were not synchronized by the positive, La Niña phase (dry winters) of the Southern Oscillation. The smaller, localized fires that occurred more frequently during the first half of the 20th century were attributed to changes in land tenure with the introduction of the ejido system in the early 1950s. Ejido management strategies lowered fire frequencies by suppressing fires and reducing anthropogenic fires. There were likely more ignitions prior to the arrival of the ejido system as fires were ignited by lightning and indigenous people. As the movement of indigenous peoples across the landscape has been restricted by changes in land tenure, numbers of human-ignited fires subsequently decreased post 1950. After 1950, fires occurred less frequently, were more synchronized, and more restricted to years of extreme climate. 相似文献
8.
Connie M. Anderson 《International journal of primatology》1981,2(4):285-310
Intertroop relations among four troops of the chacma baboon population on the Suikerbosrand Nature Reserve, southern Transvaal,
South Africa, were studied for 18 months using radiotelemetry. Encounters between troops occurred only rarely and were relatively
nonantagonistic in character. Dominance among the four troops was difficult to identify by means of behavior although differences
in range quality among the four were marked. The way in which intertroop relations affected the fitness of members of each
of the troops was, therefore, unclear. Transfer of individuals from one troop to another was easily accomplished by both males
and females and probably negated the effects of differential range quality on individual reproductive fitness. 相似文献
9.
《Ostrich》2013,84(3):591-608
Considering the frequent nature of fires and resultant drastic change in habitat following fire, research on the effects of fire on birds in the grasslands of South Africa is surprisingly scarce. For at least five months after burns we followed the changes in bird species composition, species richness and densities of two controlled burns and one accidental fire at the Barberspan Nature Reserve in grasslands that had not been burned or grazed in 10 years. Compared with the control areas, species richness and densities increased in the burned areas immediately following the burns, with more species and birds recruited to the burned areas than were lost. Immediate post-burn opportunists tended to be larger species, and the biomass increase mirrored the increases in species richness and densities in burned areas. Avian species richness, densities and biomass tended to return to the initial conditions after a number of months. Although the bird communities from two controlled-burns differed before the burns, they converged to a characteristic immediate post-burn composition. Five months after the burns however, the bird communities reflected a pre-burn composition. Indications were that birds in an area larger than that burned were affected. Mosaic burning, with shifting large and small patches, should be considered on a landscape scale. 相似文献
10.
Forest fires have environmental, social and economic impacts in many areas. Various factors related to territory directly influence both the number and the surface area of each fire. The link between different variables (climate, social and environmental) in the risk of fire and in the characteristics of fires is studied here through Partial Least Squares - Path Models. In addition, images from the Sentinel-2 sensor and geographic information systems are used to create a cartographic base of fires in the Transboundary Biosphere Reserve of Galicia and the Site of Community Importance of Xurés (Galicia) between 2015 and 2020. In all, seven variables are analyzed in this study area using the partial least squares-path modeling method: climate, topography, land use, type of environmental protection, the anthropogenic factor, fire defense, and fire data (severity and area). The parameters for each variable are used to obtain weights and thus determine the importance of each one. The areas where the problem of forest fires is greatest are those with the greatest environmental protection. Up to 31% of the surface area of the Natura 2000 Network was burned in the 6-year study period. Topography and land use are also shown to be relevant factors in the effects of forest fires in this territory. By contrast, higher population density and the development of infrastructures such as roads and water tanks mitigate the impact of fires. The problem of forest fires encompasses many variables that need to be studied. By contextualizing each study area as far as possible, specific measures to prevent and reduce damage can be drawn up. 相似文献
11.
R. J. Hobbs 《Plant Ecology》1984,57(2-3):129-136
Studies on a long-term experiment on Calluna-Eriophorum bog indicate that the length of time between management fires affects the post-fire development. A short rotation (every 10 years) results in increased dominance by Eriophorum spp. while a long rotation (every 20 years) results in greater abundance of Calluna vulgaris after fire. Variations in post-fires species abundances are related to pre-fire stand composition coupled with the patchy distribution of regeneration centers of rhizomatous species. The usefulness of burning this vegetation type in management for herbivore grazing is questioned.Nomenclature follows Tutin et al. (1964 80) for vascular plants. Smith (1978) for mosses, Watson (1981) for liverworts and Hawksworth, James & Coppins (1980) for lichens. Following common practice. Calluna vulgaris is referred to simply as Calluna.
Acknowledgements. I thank M. Raves and the Nature Conservancy Council for permission to work on Moor House National Nature Reserve and for the use of data from Reserve Records, V. J. Hobbs for field assistance, and Prof. C. H. Gimingham for help and advice during the study. I also thank all who worked at Moor House for creating a pleasant working environment. The long-term experiment was planned by Dr R. J. Elliot and analyzed initially by Dr G. I. Forrest. 相似文献
12.
R Musa 《African Journal of Aquatic Science》2018,43(1):59-69
The trophic status of the Ramsar-accredited Nyl River floodplain, which is stressed by sewage treatment effluents, and its ability to restore normal conditions, were assessed in 2014–2015 using diatoms as biological indicators. The Trophic Diatom Index, Specific Pollution Sensitivity Index and the Generic Diatom Index were used to characterise water quality under high and low flow conditions in 2014. An additional survey was conducted in May 2015, following an accidental sulphuric acid spill above the Sewage Treatment Works (STW). Significant linear correlations were identified between physico-chemical parameters and the indices, as well as between the three indices themselves, validating their use to infer water quality. Water quality deteriorated from the source of the Klein Nyl River, especially at the STW, but improved within the Nylsvley Nature Reserve wetland sampling site (NYL). 相似文献
13.
Tarboton, Warwick, 1984. Breeding of the Brubru Shrike. Ostrich 55:97-101. Brubru Shrikes occurred in pairs which occupied permanent territories 33–42 ha in size in the broadleaved woodlands at Nylsvley, Transvaal. They nested in early summer; both sexes shared equally in nest-building, incubation and brooding and feeding the young; incubation lasted 19 days (1) and the nestling period was 21–22 days (1). Vocalizations, including duet-tine, are described, and the species' phylogeny and its behaviour of deserting early nests and calling while incubating are discussed. 相似文献
14.
Charles J. Kilawe Omega E. Kaaya Christian P. Kolonel Samora A. Macrice Catherine P. Mshama Paulo J. Lyimo Cosmas J. Emily 《African Journal of Ecology》2021,59(1):204-215
The Eastern Arc Mountains are one of the most important ecosystems that conserve biodiversity in the world. These ecosystems are threatened by the increasing occurrence of wildfires. Nevertheless, there is inadequate information useful for the development of effective strategies to prevent or respond to future fires. This paper analyses the current extent of dry season fires, underlying causes and the effectiveness of the fire management strategy being implemented in and around the Uluguru Nature Forest Reserve (UNFR) between 2016 and 2021. Differenced Normalised Burn Ratio derived from Landsat satellite images was applied to determine the extent of burned areas, and focus group discussions were held to determine the underlying causes of fires and the extent of implementation of fire management strategies. About 2% (472 ha) of reserved UNFR and 5% (2,854 ha) of unreserved forests were burned in 2017. Some of the fires impacted on 60% (370 ha) of the grassy Lukwangule plateau, which is home to a fire‐sensitive endemic species. The underlying causes of fires varied spatially across the mountains but generally, fire escaping from farm preparation and hunting activities were found to be the most prevalent. On average, survey participants perceived that fire management strategy objectives were achieved by only 29% mainly constrained by a shortage of financial and human resources. Our findings suggest that ignitions and fire spread in UNFR could be prevented or controlled through sustainable funding of fire management activities and the effective engagement of local communities in the management of the reserve. 相似文献
15.
Chacha Werema 《African Journal of Ecology》2015,53(3):304-311
Fire is one of the main threats facing the long‐term survival of the forests in the Eastern Arc Mountains. Yet, our understanding of how it affects fauna, particularly birds, is still poor. A fire that originated on surrounding farmland burned approximately half of Kimboza Forest Reserve between 13 and 15 October 2010. To better understand how birds respond to fire, a short‐term study of understorey bird diversity and abundance in this forest reserve was conducted by comparing burned and unburned sites twenty months post‐fire. Capture rates were significantly higher at the unburned site compared to the burned site. Bird species diversity was also higher at the unburned site than at the burned site. Despite the brevity of the study, the results suggest that fire has negative effects on forest avifauna and forest fires need to be prevented at Kimboza Forest Reserve as they affect the distribution and diversity of understorey birds. 相似文献
16.
Sexual and associated patterns of behavior of lesser galagos (Galago moholi) were recorded during an 18-month study conducted at the Nylsvley Nature Reserve in South Africa. Animals were trapped and fitted with radio transmitter belts in order to monitor nocturnal activities during twice-yearly mating seasons. Most copulations occurred during the last week in May, while a subsidiary (post-partum) mating season occurred in late September-early October. Females came into estrus sequentially during the May season. Adult males exhibited increase in body weight and testes volume during the mating season, changes which were most pronounced among the larger males (> 226 g). Larger males also had the greatest mating success, initiating 88% of observed copulations. Sixty-seven percent of matings involved more than one male copulating with the same female during her estrus, which lasted 1-3 days. Mounts were prolonged (range 2-53 min, mean 9.0 min) and males copulated repeatedly (2-5 times) with the same partner during a single night. These observations of sexual behavior and of large relative testes size in free-ranging lesser galagos are consistent with the occurrence of a dispersed mating system involving sperm competition in this nocturnal prosimian species. 相似文献
17.
广西猫儿山自然保护区藓类植物区系研究 总被引:4,自引:1,他引:4
首次系统调查了猫儿山自然保护区的藓类植物区系。通过野外考察和室内鉴定,报道广西猫儿山藓类植物39科109属265种(含种下单位),其中广西新记录属6个,新记录种47个。其区系成分以东亚成分为主,占总种数的36.06%,其次为热带亚洲成分和北温带成分,具亚热带性质。将猫儿山自然保护区的藓类植物与四川峨眉山和云南大围山进行比较,结果显示其Gleason物种丰富度指数在三者间最低,Kroeber系数则指示出猫儿山与大围山藓类植物的属、种相似度略高于其与峨眉山的比较值。此外,区系谱的比较反映了猫儿山自然保护区藓类植物区系的东亚成分和其中的中国—日本成分在三者间最高。 相似文献
18.
Michael C. Stambaugh Richard P. Guyette Joseph Marschall 《Human ecology: an interdisciplinary journal》2013,41(5):749-758
The role of humans in historic fire regimes has received little quantitative attention. Here, we address this inadequacy by developing a fire history in northeastern Oklahoma on lands once occupied by the Cherokee Nation. A fire event chronology was reconstructed from 324 tree-ring dated fire scars occurring on 49 shortleaf pine (Pinus echinata) remnant trees. Fire event data were examined with the objective of determining the relative roles of humans and climate over the last four centuries. Variability in the fire regime appeared to be significantly influenced by human population density, culture, and drought. The mean fire interval (MFI) within the 1.2 km2 study area was 7.5 years from 1633 to 1731 and 2.8 years from 1732 to 1840. Population density of Native American groups including Cherokee was significantly correlated (r?=?0.84) with the number of fires per decade between 1680 and 1880. Coincident with the Removal of the Cherokee and other native peoples from the eastern United States and immigrations into northeast Oklahoma, the MFI decreased to 1.8 years. After 1925 fire intervals were considerably lengthened (MFI?=?16 years) due to fire suppression and decreased fire use until the recent prescribed burning by The Nature Conservancy. Many of the historic fire years that were previously shown to be synchronous across Missouri and Arkansas during drought years were also fire years at this site. Overall the frequency of fires was weakly associated with drought compared to human population density. 相似文献
19.
我国北方针叶林带是重要的森林资源储藏地,也是林火发生的重灾区,其自然火和人为火所占比例相当. 气象因子、地形特征、植被条件、人为基础设施等因素对人为火发生具有显著影响,国内目前应用空间分析技术对北方针叶林带人为火影响因子的研究还存在一定不确定性. 本文基于1974—2009年间人为火的空间地理坐标,结合研究地的气象因子、基础地理信息及矢量化林相图,应用ArcGIS 10.0中的空间分析工具和SPSS 19.0的逻辑斯蒂回归模型对影响人为火发生的主要驱动因子进行分析,并建立人为火发生的概率模型. 利用HADCM2模式下研究区域未来气象数据对塔河地区2015年人为火发生情况进行计算.结果表明: 距离铁路距离(x1)和平均相对湿度(x2)对研究区域人为火发生具有显著影响,并得到火险概率模型P=1/[1+e-(3.026-0.00011x1-0.047x2)]. 模型校验结果显示,模型的准确度可达到80%.林火发生预测结果表明,塔河地区2015年 4—6月、8月为人为火高发期,其中,4—5月的林火发生概率最高.从火险空间分布来看,高火险主要集中在塔河西部和西南部,铁路线路主要包含在此区域. 相似文献
20.
应用空间直观火行为模型模拟大的时空尺度上的林火蔓延过程成为林火管理、规划和科学分析的有效工具。FARSITE(Fire Area Simulator)是一个基于热物理、燃烧学和试验理论为一体的空间直观火行为模型,它集成了现有的地表火、树冠火、飞火和火加速等子模型。FARSITE能够利用GIS和RS提供的空间数据,模拟大时空尺度的林火蔓延,模拟结果能够以地图形式输出,反映林火行为的瞬时状态。本文介绍了FARSITE模型的基本原理、结构和运行机制,并将其应用到丰林自然保护区林火蔓延模拟,以期为国内林火管理和火行为模型的开发提供参考。 相似文献