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1.
In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.  相似文献   

2.
Hexarthra bulgarica was found in 16 of the 37 high mountain lakes (over 2500 m) studied in the Sierra Nevada (Southern Spain). These populations resemble closely the subspecies H. b. canadensis. Data on the morphology and ecology of the Sierra Nevada populations are given, and these are compared to published information on the three other subspecies of H. bulgarica.Research supported by CAICYT Project No. 3069/83.  相似文献   

3.
The effects of pulsed acidification on invertebrate densities and drift, and water chemistry, in a high altitude Sierra Nevada stream were measured using artificial stream channels. Water was diverted from the Marble Fork of the Kaweah River, California, U.S.A., through twelve replicate channels; however, low flow in the summer of 1985 eliminated all but four of these channels. Channels were stocked with natural substrates and organisms from the Marble Fork of the Kaweah River. After a three week acclimation period, we simulated a low pH rain event by adding acid (H2SO4 and HNO3) to two of the channels, reducing pH to 5.0 for 6 hours. The other two channels acted as controls (pH 6.4). During acid additions, Baetis spp. drift in acidified channels was ca. 7 times higher than in control channels (F = 39.02, p < 0.025; data fourth root transformed, ANOVA), and the percentage of drifting baetids that was dead was significantly higher in acidified than control channels (46% vs. 0%, F = 29.86, p < 0.05; arcsine square root transformed data, ANOVA). Other taxa showed no significant drift responses, and benthic densities of all taxa showed no effects two days after acidification, probably owing to rapid recolonization by invertebrate drift in influent waters. Stream chemistry data are presented; heavy metal concentrations did not significantly increase in the 2 m stream channels.  相似文献   

4.
Morales-Baquero  R.  Cruz-Pizarro  L.  Carrillo  P. 《Hydrobiologia》1989,186(1):215-221
On the basis of periodic collections of rotifers from 29 lakes and ponds over 2500 m above sea level in the Sierra Nevada (Southern Spain), patterns of species richness, distribution and community composition were evaluated. Results allow us to distinguish communities which fall into two major lake types. One is defined by the presence of typically planktonic species as well as lower specific richness whereas the other includes communities of mainly benthic and periphytic species. Both lake types seem to be related to small differences in their physical and chemical characteristics. These relationships and the influence of littoral vegetation are discussed.Research supported by CAICYT Project n° 3069/83  相似文献   

5.
Effective management of grazers requires understanding of the mechanisms influencing population declines. Roan antelope, a specialist grazer, has declined in population numbers within Kruger National Park, South Africa. The most widely accepted hypothesis is that habitat deterioration throughout the entire northern plains landscape is responsible for declines in this species. Observations suggest, however, that on the northern plains of Kruger National Park, roan antelope grazes at the boundary between ephemeral wetland and the savanna matrix. The boundary is characterized by nutrient-rich soil and forage, and thus attracts grazing from both generalist and specialist species. We hypothesize that competition for resources at this ecotone, and not at other places in the landscape, is responsible for the observed declines in roan antelope. Changing management strategies to be more cognizant of patchiness and savanna heterogeneity, i.e. more spatially informed, will improve the likelihood that management will result in increasing roan population numbers.  相似文献   

6.
Mura  Graziella 《Hydrobiologia》1997,346(1-3):11-23
The life cycle of Chirocephalus kerkyrensis, a typicalspecies of the Mediterranean plain forest, was studied in thefield during 1990/91 and 1991/92.Temperature, and its variation, was the major factor affectinglife history. Marked, sudden temperature fluctuations resultedin depressed growth and longevity. Fertility was positivelycorrelated (P<0.001) with female body length. Nodecline in egg production was observed at the end of life, incontrast to other species. Hatching was observed after a longdrought followed by alternating wet and dry phases. Laboratorytests on hatching gave contrasting results and showed thatdrying is not obligatory. Cysts stored in 100% relativehumidity gave higher numbers of nauplii after a shorter timethan dried ones, at all temperatures tested.  相似文献   

7.
Forest fires lead to the annual disappearance of many natural formations that require the creation of firewall areas. They can be maintained by enriching their pastures with attractive plants for grazing livestock, mainly legumes, which have a high protein content and low dependence on N fertilizers due to their ability to establish nitrogen-fixing symbiosis with rhizobia. In this study, the rhizobia isolated from the nodules of six legumes from the genera Vicia, Lathyrus and Trifolium were analysed in a firewall zone established in Lanjarón (Granada) close to the Sierra Nevada National Park (Spain). The results showed a high genetic diversity of the isolated strains that had 3, 16, 14 and 13 different types of rrs, recA, atpD and glnII genes, respectively. All strains were phylogenetically close to the species from the Rhizobium leguminosarum group, although they were not identified as any of them. The isolated strains belonged to the symbiovars viciae and trifolii but high phylogenetic diversity was found within both symbiovars, since there were 16 and 14 nodC gene types, respectively. Some of these strains clustered with strains isolated in other countries and continents, but others formed atpD, recA, glnII and nodC clusters and lineages only found to date in this study.  相似文献   

8.
Climatic influence (global warming and decreased rainfall) could lead to an increase in the ecological and toxicological effects of the pollution in aquatic ecosystems, especially contamination from agricultural nitrate (NO3) fertilizers. Physicochemical properties of the surface waters and sediments of four selected sites varying in NO3 concentration along La Rocina Stream, which feeds Marisma del Rocio in Doñana National Park (South West, Spain), were studied. Electrical conductivity, pH, content in macro and microelements, total organic carbon and nitrogen, and dissolved carbon and nitrogen were affected by each sampling site and sampling time. Contaminant NO3 in surface water at the site with the highest NO3 concentration (ranged in 61.6-106.6 mg L−1) was of inorganic origin, most probably from chemical fertilizers, as determined chemically (90% of the total dissolved nitrogen from NO3) and by isotopic analysis of δ15N-NO3. Changes in seasonal weather conditions and hydrological effects at the sampling sites were also responsible for variations in some biological activities (dehydrogenase, β-glucosidase, arylsulphatase, acid phosphatase and urease) in sediments, as well as in the production of the greenhouse gases CO2, CH4 and N2O. Both organic matter and NO3 contents influenced rates of gas production. Increased NO3 concentration also resulted in enhanced levels of potential denitrification measured as N2O production. The denitrification process was affected by NO3 contamination and the rainfall regimen, increasing the greenhouse gases emissions (CO2, CH4 and especially N2O) during the driest season in all sampling sites studied.  相似文献   

9.
The carnivore community of Arusha National Park, Tanzania, was monitored using live trapping and diurnal and nocturnal visual counts and recording of tracks and signs along line transects. Nine carnivore species were recorded. Hyena (Crocuta crocuta), the most common large species, leopard (Panthera pardus) and African civet (Civettictis civetta) were detected along line transects, while the smaller species were counted and/or captured. Mungos mungo, Galerella sanguinea, and Genetta maculata were the most prevalent at transect counts, while G. sanguinea, Bdeogale crassicauda, and G. maculata were most frequently captured. Ichneumia albicauda and Ictonyx striatus were captured at only a single site. Carnivores selected natural habitat types, multilayered forest, open shrubs and herbaceous savannah, and were absent, or tended to avoid disturbed (man-made) habitats. Species of which sufficient data were gathered seemed to behave as habitat generalists (C. crocuta, G. sanguinea, G. maculata, M. mungo and I. striatus). The need for more detailed studies on small carnivore ecology and the importance of smaller protected areas for their conservation are discussed.  相似文献   

10.
Studies on the nutritive ecology of red colobus monkeys (Colobus badius preussi) in Korup National Park, Cameroon, investigated food plants and the parts eaten as well as nutritive values of the various food items. Food plants were identified through direct observations and collected for laboratory determination of nutrient content. Food plants were analysed for crude protein (CP), crude fibre (CF), ether extract (EE), nitrogen‐free‐extractive (NFE) and total ash (A). A total of seventeen species belonging to nine different families were identified as food plants for red colobus. Food and feeding habits showed that the species were highly folivorous, tending to prefer the young leaves of food plants. Lecomtedoxa klaineana (27.0%) and Xylopia aethiopica (22.2%) of families Sapotaceae and Annonaceae, respectively, constituted about 50% of total food items consumed. Results of nutrient composition indicated individual nutrients varied significantly (P < 0.01) with food species.  相似文献   

11.
The relationship between vegetation cover and soil seed banks was studied in five different ungulate herbivore-prairie dog treatment combinations at three northern mixed-grass prairie sites in Badlands National Park, South Dakota. There were distinct differences in both the seed bank composition and the aboveground vegetation between the off-prairie dog colony treatments and the on-colony treatments. The three on-colony treatments were similar to each other at all three sites with vegetation dominated by the forbs Dyssodia papposa, Hedeoma spp., Sphaeralcea coccinea, Conyza canadensis, and Plantago patagonica and seed banks dominated by the forbs Verbena bracteata and Dyssodia papposa. The two off-colony treatments were also similar to each other at all three sites. Vegetation at these sites was dominated by the grasses Pascopyrum smithii, Bromus tectorum and Bouteloua gracilis and the seed banks were dominated by several grasses including Bromus tectorum, Monroa squarrosa, Panicum capillare, Sporobolus cryptandra and Stipa viridula. A total of 146 seedlings representing 21 species germinated and emerged from off-colony treatments while 3069 seedlings comprising 33 species germinated from on-colony treatments. Fifteen of the forty species found in soil seed banks were not present in the vegetation, and 57 of the 82 species represented in the vegetation were not found in the seed banks. Few dominant species typical of mixed-grass prairie vegetation germinated and emerged from seed banks collected from prairie dog colony treatments suggesting that removal of prairie dogs will not result in the rapid reestablishment of representative mixed-grass prairie unless steps are taken to restore the soil seed bank.  相似文献   

12.
The territorial system of kob antelopes in the Comoé National Park, Côte d'Ivoire, was studied from March 1993 until April 1997. Whereas size and shape of territories remained constant between 1993 and 1994, the number of territories decreased from 1994 onwards. A decline of the population density probably led to the decline in territory numbers and also to variations in size and shape of the remaining territories. The decline of kob numbers is the result of heavy poaching in the study area. Whereas a lekking system was present in the study area prior to 1975 when the population density was approximately 14.4 kobs/km2, males switched to the resource defence territorial system present today after the population density decreased to 12.5/km2 in 1993 and finally to 2.3/km2 in 1997. Compared to other research areas with higher population densities, territories in the Comoé National Park are larger, almost all adult males are capable to defend a territory, fights over territories are rare and loss of territory tenureship is almost exclusively due to the death of the territorial male. We suggest that those differences can all be related to the low population density in the study area.  相似文献   

13.
Morales-Baquerol  R.  Carrillo  P.  Cruz-Pizarro  L. 《Hydrobiologia》1995,313(1):359-363
We examine the development of Hexarthra bulgarica (Wisniewski) populations in relation to thermal stability in natural environments. A high frequency sampling program was developed simultaneously in two high mountain lakes: a shallow one, with daily large temperature changes but little surface-bottom temperature difference and a deeper one with more stable temperature but vertical heterogeneity in the water profile. Since the capacity of H. bulgarica to perform vertical migrations in these lakes of Sierra Nevada is already known, we have studied the relationship between egg ratios and chlorophyll-a concentration, mean temperatures and temperature instability (measured as the daily rate of temperature change — TCR — as well as the surface-bottom temperature difference — SBT -) in both lakes. Results show that the intensity of temperature fluctuations has a positive effect on the egg-ratios, as TCR is only correlated with that variable in the shallow lake and SBT is only correlated with egg-ratios in the deeper one.  相似文献   

14.
15.
A survey in 1994 examined intestinal helminths and bacterial flora of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda. Parasites and bacteria were identified to genus in the feces of two groups of tourist-habituated and one group of non-tourist-habituated mountain gorillas. Eggs were identified as those of an anoplocephalid cestode, and nematode eggs representative of the genera: Trichuris, Ascaris, Oesophagostomum, Strongyloides, and Trichostrongylus. This is the first report of Ascaris lumbricoides-like eggs in mountain gorillas. Fecal samples (n=76) from all groups contained helminth eggs, with strongyle eggs and anoplocephalid eggs being the most common. Salmonella and Campylobacter were found in both gorilla groups. Regular long-term non-invasive fecal monitoring of the populations of mountain gorillas is essential for the prevention and identification of potential health threats by intestinal parasites and bacteria in this highly endangered subspecies.This revised version was published online in April 2005 with corrections to the cover date of the issue.  相似文献   

16.
17.
《Ostrich》2013,84(1):83-88
The paper ‘Bird diversity in the savanna habitats of Akagera National Park, Rwanda, in the post-war recovery period’ by Gatali and Wallin (Ostrich 86(3): 267–276, 2015) makes several claims for new species records for Akagera National Park and Rwanda. We found that Gatali and Wallin recorded several species considered very rare in Rwanda and new discoveries; these findings often contradicted the existing literature. We doubt the validity of 34 species records and we aim to demonstrate that these claims are mostly the result of misidentification or human error and consider that future researchers should use their findings with caution. Some findings around more common species may be validated through further studies and we encourage others to conduct fieldwork in Akagera National Park.  相似文献   

18.
Population declines caused by natural and anthropogenic factors can quickly erode genetic diversity in natural populations. In this study, we examined genetic variation within 10 tiger salamander populations across northern Yellowstone National Park in Wyoming and Montana, USA using eight microsatellite loci. We tested for the genetic signature of population decline using heterozygosity excess, shifts in allele frequencies, and low ratios of allelic number to allelic size range (M-ratios). We found different results among the three tests. All 10 populations had low M-ratios, five had shifts in allele frequencies and only two had significant heterozygosity excesses. These results support theoretical expectations of different temporal signatures among bottleneck tests and suggest that both historical fish stocking, recent, sustained drought, and possibly an emerging amphibian disease have contributed to declines in effective population size.  相似文献   

19.
The ecological structure and diversity of woody species in the Cistus ladanifer shrubland (jaral), one of the most widespread Mediterranean scrub systems in the western half of the Iberian Peninsula, was studied in Extremadura (CW Spain). 57 points were sampled for presence/absence and abundance (line interception) of woody species. Several diversity indices were calculated to elucidate the role of both C. ladanifer and bare soil in the jaral structure. The sites were classified by agglomerative hierarchical clustering and ordinated by Principal Component Analysis (PCA). Most of the examined scrubs have diversity within the range 1–3, evenness above 0.5 and species richness between 1 and 12. Clustering and PCA distinguished three groups of scrubs: A, those with a certain Atlantic influence and highest values of diversity and total cover, in which Lavandula stoechas subsp. luisieri, Erica umbellata and Halimium ocymoides are frequent; B, the most continental scrubs, growing on moderately acid soils with Cistus salvifolius and C. crispus, and, C, those as continental as group B but on more acid soils, characterized by Genista hirsuta. Differential species between groups basically coincide with those used in phytosociological classifications. Diversity data, together with affinity and PCA analyses, emphasize that the ecological structure of Mediterranean shrublands is strongly influenced by humidity and the annual temperature range.  相似文献   

20.
After the first report of Brucella melitensis infection from a 7-year-old alpine ibex (Capra ibex) buck living in Gran Paradiso National Park (GPNP), further studies demonstrated the presence of the infection in ibex and chamois. Considering that livestock herds keep on sharing pastures with more than 3,500 ibex and 9,000 chamois in the park, our aim was to demonstrate under controlled conditions the possibility of Brucella infection passing from wild ruminants to livestock. A 7-year-old male alpine ibex with clinical signs of brucellosis and serologically positive was released in a 5,000 m2 enclosure together with five goats and two sheep rams. Due to poor condition, ibex was suppressed at day 40, domestic ruminants stayed into the enclosure potentially contaminated by ibex for further 38 days. During this period, we had monitored our animals taking blood from domestic ruminants every 15 days and tested the serum to Rose Bengal agglutination test and Complement Fixation test. Domestic animals tested negative at serology at all sampling time and at isolation, while B. melitensis biovar 3 was isolated from ibex tissues. Our data show that transmission of infection from ibex to livestock is not easy. After 40 days of strict cohabitation and 38 days of permanence in an area where an infected ibex lives, no one of the domestic animals contracted infection. In spite of the limitation of our field trial, we have demonstrated that long direct and indirect contact between alpine ibex and domestic animals will not easily lead to an infection of the latter. Further investigations are needed to confirm our results and evaluate the effective risk of B. melitensis transmission from alpine ibex to livestock.  相似文献   

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