We analyze morphometrics from a sample of 276 White-winged Black Tern(Chlidonias leucopterus) caught in north-west Australia on 4 March 2011. An estimated 40000 terns were present — the largest concentration of this ...We analyze morphometrics from a sample of 276 White-winged Black Tern(Chlidonias leucopterus) caught in north-west Australia on 4 March 2011. An estimated 40000 terns were present — the largest concentration of this species yet reported from Australia. When comparing juveniles with adults, only wing length and body mass differed significantly; however, juveniles were still easily recognized by plumage and wing molt as late as March. There was little evidence of any dramatic weight gain in adults before their northward migration. No morphological characteristic distinguishing sex was found. We confirmed that terns caught in this study did not appear to differ morphologically from those of the western palearctic populations. We describe wing molt based on data from 354 individuals captured and banded in Australia over 28 years. Wing molt proceeds in much the same way as found in other small terns.展开更多
We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on dem...We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on demographics and movement patterns. The population＇s age-group composition was 58% adults, 25% sub-adults, 9% juveniles, 5% calves and 3% unidentified with a female-male sex ratio of 2：1. Population density was found to be significantly different between the two sub-populations （Dinsho Sanctuary and Gaysay/Adelay）. A significant difference was found for age-group composition across the two sub-populations except adult females, sub-adult males and calves. The Dinsho sub-population was an isolated group. Separation and containment of the mountain nyala population could have negatively affected their ability to search for habitat requirements and mates from distant areas. The population varied between 830-908 individuals （95% CI）, a reduction of 45% from earlier reports. However, the mean population density increased due to contraction of the species＇ habitat range. We observed a population decrease of 2%-5% per year over the course of our study. Many of the assessed demographic parameters did not significantly change over the three years. This suggests that the decrease in nyala population was not due to random variations in reproduction. Anthropogenic factors such as competition with livestock for forage, habitat encroachment and poaching by the local people might have been partly responsible for the depleted population in our study areas [Current Zoology 56 （6）： 660q569, 2010].展开更多
Human activities in the Lake Naivasha catchments pose serious ecological threats to sustainable freshwater ecosystem management. The future hangs on the balance of economic exploitation and sustainable watershed conse...Human activities in the Lake Naivasha catchments pose serious ecological threats to sustainable freshwater ecosystem management. The future hangs on the balance of economic exploitation and sustainable watershed conservation. Water abstraction volumes, embedded water/virtual water and chemical analysis of wastewater discharges were assessed. Dissolved oxygen, temperature, Secchi disc depth, benthic organisms＇ population and pesticides used in the farms were determined. The study found that abstraction exceeds safe water yield, farms have also encroached on the riparian lands and connected to the lake through canals allowing effluents to flow directly to the lake. Benthic community populations are low at points where discharge canals enter the lake, indicating inflow of materials are toxic. Canal samples show high contaminant levels of actions for sustainable exploitation of the resource is essential. compared to other sites. Wise use of the resource and implementation The determination of ecological and water footprints are recommend.展开更多
The present paper refers to some data regarding zoobenthic communities from one of northern lagoon of the Danube delta, known as Musura bay （ROSCI0065, coded as coastal lagoon ＊ 1150）. Faunal composition is influen...The present paper refers to some data regarding zoobenthic communities from one of northern lagoon of the Danube delta, known as Musura bay （ROSCI0065, coded as coastal lagoon ＊ 1150）. Faunal composition is influenced by the mixture of waters from the Danube and the marine coastal zone. According to monitored areas, there are dominant freshwater or marine invertebrates forming populations that live in the sediments. The aim of this paper is to offer a view of the endopsammic and endopelitic benthic communities from Musura bay, during two years of observations （2013 and 2014） and analyze the seasonal dynamics of invertebrates＇ populations. Based on quantitative samples collected from infralittoral zone, the paper presents the qualitative structure and a quantitative analyze （abundance, constancy--F%, dominance--D% and Wo%） of invertebrate populations from all taxa （belonging to Foraminifera, Nematoda, Gasteropoda, Oligochaeta, Polychaeta, Ostracoda, Copepoda, Cumacea, Amphipoda and Chironomidae etc.） found in the researched zones, in connection with variation of local ecological conditions. Some considerations regarding the role of invertebrates＇ populations as food resources for lagoon fishes are done,展开更多
The hemimetabolous preliminary studies on the life cycle of Indocnemis orang is here reported for the first time, being completed in 6 instars for a minimum duration of 69 days. It can be classified as a stenotopic s...The hemimetabolous preliminary studies on the life cycle of Indocnemis orang is here reported for the first time, being completed in 6 instars for a minimum duration of 69 days. It can be classified as a stenotopic species being sensitive to biotope requirements but having tolerance towards fluctuating water qualities during its developmental process. The need for caution in the interpretation of bioindicator species for habitat assessment and biomonitoring is here both indicated and discussed.展开更多
Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throu...Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germin- ation and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns （Quercus spp.） on Santa Cruz Island. We use a large behavioral data set on the birds＇ behavior in combination with seedling surveys and spatial analysis to determine whether 1） island scrub jays disproportionally cache seeds in specific habitat types, and 2） whether the preferred habitat type is suitable for oak regeneration. Our results show that the jays nonrandomly cache acorns across the landscape; they use chaparral and coastal sage scrub disproportionally while avoiding open and grassy areas. The areas used most often for caching were also the areas with the highest oak seedling densities. We discuss the potential role of these findings for the recovery of Santa Cruz Island＇s oak habitat since the 1980s.展开更多
Populations of the endangered mountain nyala Tragelaphus buxtoni are significantly threatened by the loss of critical habitat. Population estimates are tentative, and information on the species＇ distribution and avai...Populations of the endangered mountain nyala Tragelaphus buxtoni are significantly threatened by the loss of critical habitat. Population estimates are tentative, and information on the species＇ distribution and available habitat is required for for-mulating immediate management and conservation strategies. To support management decisions and conservation priorities, we integrated information from a number of small-scale observational studies, interviews and reports from multiple sources to define habitat parameters and create a habitat quality model for mountain nyala in the Bale Mountains. For our analysis, we used the FunConn model, an expertise-based model that considers spatial relationships （i.e., patch size, distance） between the species and vegetation type, topography and disturbance to create a habitat quality surface. The habitat quality model showed that approxi- mately 18,610 km^2 （82.7% of our study area） is unsuitable or poor habitat for the mountain nyala, while 2,857 km^2 （12.7%） and 1,026 km^2 （4.6%） was ranked as good or optimal habitat, respectively. Our results not only reflected human induced habitat deg-radation, but also revealed an extensive area of intact habitat on the remote slopes of the Bale Mountain＇s southern and southeast- ern escarpments. This study provides an example of the roles that expert knowledge can still play in modem geospatial modeling of wildlife habitat. New geospatial tools, such as the FunConn model, are readily available to wildlife managers and allow them to perform spatial analyses with minimal software, data and training requirements. This approach may be especially useful for species that are obscure to science or when field surveys are not practical .展开更多
文摘We analyze morphometrics from a sample of 276 White-winged Black Tern(Chlidonias leucopterus) caught in north-west Australia on 4 March 2011. An estimated 40000 terns were present — the largest concentration of this species yet reported from Australia. When comparing juveniles with adults, only wing length and body mass differed significantly; however, juveniles were still easily recognized by plumage and wing molt as late as March. There was little evidence of any dramatic weight gain in adults before their northward migration. No morphological characteristic distinguishing sex was found. We confirmed that terns caught in this study did not appear to differ morphologically from those of the western palearctic populations. We describe wing molt based on data from 354 individuals captured and banded in Australia over 28 years. Wing molt proceeds in much the same way as found in other small terns.
文摘We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on demographics and movement patterns. The population＇s age-group composition was 58% adults, 25% sub-adults, 9% juveniles, 5% calves and 3% unidentified with a female-male sex ratio of 2：1. Population density was found to be significantly different between the two sub-populations （Dinsho Sanctuary and Gaysay/Adelay）. A significant difference was found for age-group composition across the two sub-populations except adult females, sub-adult males and calves. The Dinsho sub-population was an isolated group. Separation and containment of the mountain nyala population could have negatively affected their ability to search for habitat requirements and mates from distant areas. The population varied between 830-908 individuals （95% CI）, a reduction of 45% from earlier reports. However, the mean population density increased due to contraction of the species＇ habitat range. We observed a population decrease of 2%-5% per year over the course of our study. Many of the assessed demographic parameters did not significantly change over the three years. This suggests that the decrease in nyala population was not due to random variations in reproduction. Anthropogenic factors such as competition with livestock for forage, habitat encroachment and poaching by the local people might have been partly responsible for the depleted population in our study areas [Current Zoology 56 （6）： 660q569, 2010].
文摘Human activities in the Lake Naivasha catchments pose serious ecological threats to sustainable freshwater ecosystem management. The future hangs on the balance of economic exploitation and sustainable watershed conservation. Water abstraction volumes, embedded water/virtual water and chemical analysis of wastewater discharges were assessed. Dissolved oxygen, temperature, Secchi disc depth, benthic organisms＇ population and pesticides used in the farms were determined. The study found that abstraction exceeds safe water yield, farms have also encroached on the riparian lands and connected to the lake through canals allowing effluents to flow directly to the lake. Benthic community populations are low at points where discharge canals enter the lake, indicating inflow of materials are toxic. Canal samples show high contaminant levels of actions for sustainable exploitation of the resource is essential. compared to other sites. Wise use of the resource and implementation The determination of ecological and water footprints are recommend.
文摘The present paper refers to some data regarding zoobenthic communities from one of northern lagoon of the Danube delta, known as Musura bay （ROSCI0065, coded as coastal lagoon ＊ 1150）. Faunal composition is influenced by the mixture of waters from the Danube and the marine coastal zone. According to monitored areas, there are dominant freshwater or marine invertebrates forming populations that live in the sediments. The aim of this paper is to offer a view of the endopsammic and endopelitic benthic communities from Musura bay, during two years of observations （2013 and 2014） and analyze the seasonal dynamics of invertebrates＇ populations. Based on quantitative samples collected from infralittoral zone, the paper presents the qualitative structure and a quantitative analyze （abundance, constancy--F%, dominance--D% and Wo%） of invertebrate populations from all taxa （belonging to Foraminifera, Nematoda, Gasteropoda, Oligochaeta, Polychaeta, Ostracoda, Copepoda, Cumacea, Amphipoda and Chironomidae etc.） found in the researched zones, in connection with variation of local ecological conditions. Some considerations regarding the role of invertebrates＇ populations as food resources for lagoon fishes are done,
文摘The hemimetabolous preliminary studies on the life cycle of Indocnemis orang is here reported for the first time, being completed in 6 instars for a minimum duration of 69 days. It can be classified as a stenotopic species being sensitive to biotope requirements but having tolerance towards fluctuating water qualities during its developmental process. The need for caution in the interpretation of bioindicator species for habitat assessment and biomonitoring is here both indicated and discussed.
文摘Scatter hoarding by corvids （crows, jays, magpies, and nutcrackers） provides seed dispersal for many large-seeded plants, including oaks and pines. When hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. In the context of habitat restoration, such disproportional storing of seeds in areas suitable for germin- ation and establishment can accelerate expansion and recovery of large-seeded tree populations and their associated ecosystems. Here, we investigate the spatial preferences of island scrub jays Aphelocoma insularis during scatter hoarding of acorns （Quercus spp.） on Santa Cruz Island. We use a large behavioral data set on the birds＇ behavior in combination with seedling surveys and spatial analysis to determine whether 1） island scrub jays disproportionally cache seeds in specific habitat types, and 2） whether the preferred habitat type is suitable for oak regeneration. Our results show that the jays nonrandomly cache acorns across the landscape; they use chaparral and coastal sage scrub disproportionally while avoiding open and grassy areas. The areas used most often for caching were also the areas with the highest oak seedling densities. We discuss the potential role of these findings for the recovery of Santa Cruz Island＇s oak habitat since the 1980s.
文摘Populations of the endangered mountain nyala Tragelaphus buxtoni are significantly threatened by the loss of critical habitat. Population estimates are tentative, and information on the species＇ distribution and available habitat is required for for-mulating immediate management and conservation strategies. To support management decisions and conservation priorities, we integrated information from a number of small-scale observational studies, interviews and reports from multiple sources to define habitat parameters and create a habitat quality model for mountain nyala in the Bale Mountains. For our analysis, we used the FunConn model, an expertise-based model that considers spatial relationships （i.e., patch size, distance） between the species and vegetation type, topography and disturbance to create a habitat quality surface. The habitat quality model showed that approxi- mately 18,610 km^2 （82.7% of our study area） is unsuitable or poor habitat for the mountain nyala, while 2,857 km^2 （12.7%） and 1,026 km^2 （4.6%） was ranked as good or optimal habitat, respectively. Our results not only reflected human induced habitat deg-radation, but also revealed an extensive area of intact habitat on the remote slopes of the Bale Mountain＇s southern and southeast- ern escarpments. This study provides an example of the roles that expert knowledge can still play in modem geospatial modeling of wildlife habitat. New geospatial tools, such as the FunConn model, are readily available to wildlife managers and allow them to perform spatial analyses with minimal software, data and training requirements. This approach may be especially useful for species that are obscure to science or when field surveys are not practical .
