Short-term recolonization of stones in a tropical island stream

2002 ◽  
Vol 53 (6) ◽  
pp. 993 ◽  
Author(s):  
Luz Boyero ◽  
Jose Luis DeLope
Keyword(s):  
Significant Variation ◽  
National Park ◽  
Taxonomic Composition ◽  
Total Density ◽  
Community Characteristics ◽  
Tropical Stream ◽  
Short Term ◽  
Taxa Richness ◽  
Abiotic Variables ◽  
Community Evenness

The recolonization of stones by macroinvertebrates in streams can occur at very small temporal scales, an often-neglected factor in recolonization studies. In a tropical stream in Coiba National Park, Panama, 36 stones were washed and brushed and each one was subjected to four different periods of exposure in a riffle (1, 3, 9, 27 h). Ephemeroptera, together with Diptera, Trichoptera, Coleoptera, Lepidoptera and Hydracarina, were the main recolonizers. Total density of individuals, and density and relative abundance of the most common taxon (Baetidae : Ephemeroptera), showed significant variation over the four recolonization periods, partially explained by some abiotic variables (water depth, current velocity and stone shape). Taxa richness, community evenness and taxonomic composition did not vary significantly over the four periods. The recolonization of stones in the tropical stream began immediately after the disturbance, although only some community characteristics varied significantly over the first hours.

scholarly journals Carbon Source Preference in Chemosynthetic Hot Spring Communities

2015 ◽  
Vol 81 (11) ◽  
pp. 3834-3847 ◽  
Author(s):  
Matthew R. Urschel ◽  
Michael D. Kubo ◽  
Tori M. Hoehler ◽  
John W. Peters ◽  
Eric S. Boyd
Keyword(s):  
High Temperature ◽  
National Park ◽  
Hot Springs ◽  
Dissolved Inorganic Carbon ◽  
Hot Spring ◽  
Affinity Constant ◽  
Rrna Gene ◽  
Organic Substrates ◽  
Short Term ◽  
Acetate Assimilation

ABSTRACTRates of dissolved inorganic carbon (DIC), formate, and acetate mineralization and/or assimilation were determined in 13 high-temperature (>73°C) hot springs in Yellowstone National Park (YNP), Wyoming, in order to evaluate the relative importance of these substrates in supporting microbial metabolism. While 9 of the hot spring communities exhibited rates of DIC assimilation that were greater than those of formate and acetate assimilation, 2 exhibited rates of formate and/or acetate assimilation that exceeded those of DIC assimilation. Overall rates of DIC, formate, and acetate mineralization and assimilation were positively correlated with spring pH but showed little correlation with temperature. Communities sampled from hot springs with similar geochemistries generally exhibited similar rates of substrate transformation, as well as similar community compositions, as revealed by 16S rRNA gene-tagged sequencing. Amendment of microcosms with small (micromolar) amounts of formate suppressed DIC assimilation in short-term (<45-min) incubations, despite the presence of native DIC concentrations that exceeded those of added formate by 2 to 3 orders of magnitude. The concentration of added formate required to suppress DIC assimilation was similar to the affinity constant (Km) for formate transformation, as determined by community kinetic assays. These results suggest that dominant chemoautotrophs in high-temperature communities are facultatively autotrophic or mixotrophic, are adapted to fluctuating nutrient availabilities, and are capable of taking advantage of energy-rich organic substrates when they become available.

scholarly journals Effect of burning on the numbers of questing ticks collected by dragging

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
I.G. Horak ◽  
G.J. Gallivan ◽  
A.M. Spickett ◽  
A.L.F. Potgieter
Keyword(s):  
Tick Species ◽  
National Park ◽  
Host Preference ◽  
Term Effect ◽  
Kruger National Park ◽  
Ixodid Ticks ◽  
Short Term ◽  
Experimental Burn ◽  
Major Species ◽  
Questing Ticks

Sixteen experimental burn plot replicates, in groups of four, in four landscape zones of the Kruger National Park, South Africa, and from which wildlife are not excluded, have been subjected to fixed, regular burning regimens since 1954. In 1999, a study to determine the effect of burning on ixodid ticks questing for hosts from the vegetation of the plots was initiated, and six sub-plots, with identical histories, within each of two of the burn plot replicates in Combretum collinum / Combretum zeyheyri woodland on granite, were selected. With few exceptions these 12 sub-plots, as well as unburned vegetation adjacent to each of the replicates, were sampled for ticks at monthly intervals for a period of 39 months by dragging with flannel strips. The existing regimen of burning during August or during October on individual sub-plots was continued during this time. A total of 14 tick species was recovered from the plots of which nine could be considered major species. Sufficient numbers for statistical analysis of only eight species were, however, collected. Burning appeared to have little short-term effect on the number of ticks recovered. In the longer term, the response varied from no change, an increase, or a decrease in the numbers of ticks collected each year after burning. Tick species, life cycle, seasonality, questing strategy, host preference and host utilization of the habitat were important determinants of the effect of burning.

scholarly journals Prediksi Kunjungan Wisatawan Taman Nasional Gunung Merbabu dengan Time Series Forecasting dan LSTM

2020 ◽  
Vol 11 (2) ◽  
pp. 131
Author(s):  
Josua Manullang ◽  
Albertus Joko Santoso ◽  
Andi Wahju Rahardjo Emanuel
Keyword(s):  
Time Series ◽  
National Park ◽  
Short Term Memory ◽  
Lag Time ◽  
Time Series Forecasting ◽  
Mean Square ◽  
Short Term ◽  
Term Memory ◽  
Long Short Term Memory

Abstract. Prediction of tourist visits of Mount Merbabu National Park (TNGMb) needs to be done to control the number of visitors and to preserve the national park. The combination of time series forecasting (TSF) and deep learning methods has become a new alternative for prediction. This case study was conducted to implement several methods combination of TSF and Long-Short Term Memory (LSTM) to predict the visits. In this case study, there are 18 modelling scenarios as research objects to determine the best model by utilizing tourist visits data from 2013 to 2018. The results show that the model applying the lag time method can improve the model's ability to capture patterns on time series data. The error value is measured using the root mean square error (RMSE), with the smallest value of 3.7 in the LSTM architecture, using seven lags as a feature and one lag as a label.Keywords: Tourist Visit, Taman Nasional Gunung Merbabu, Prediction, Recurrent Neural Network, Long-Short Term MemoryAbstrak. Prediksi kunjungan wisatawan Taman Nasional Gunung Merbabu (TNGMb) perlu dilakukan untul pengendalian jumlah pengunjung dan menjaga kelestarian taman nasional. Gabungan metode antara time series forecasting (TSF) dan deep learning telah menjadi alternatif baru untuk melakukan prediksi. Studi kasus ini dilakukan untuk mengimplementasi gabungan dari beberapa macam metode antara TSF dan Long-Short Term Memory (LSTM) untuk memprediksi kunjungan pada TNGMb. Pada studi kasus ini, terdapat 18 skenario pemodelan sebagai objek penelitian untuk menentukan model terbaik, dengan memanfaatkan data jumlah kunjungan wisatawan di TNGMb mulai dari tahun 2013 sampai dengan tahun 2018. Hasil prediksi menunjukkan pemodelan dengan menerapkan metode lag time dapat meningkatakan kemampuan model untuk menangkap pola pada data deret waktu. Besar nilai kesalahan diukur menggunakan root mean square error (RMSE), dengan nilai terkecil sebesar 3,7 pada arsitektur LSTM, menggunakan tujuh lag sebagai feature dan satu lag sebagai label. Kata Kunci: Kunjungan Wisatawan, Taman Nasional Gunung Merbabu, Prediksi, Recurrent Neural Network, Long-Short Term Memory

scholarly journals Institutional Investor Attention and Firm Disclosure

2020 ◽  
Vol 95 (6) ◽  
pp. 1-21 ◽  
Author(s):  
Inna Abramova ◽  
John E. Core ◽  
Andrew Sutherland
Keyword(s):  
Significant Variation ◽  
Information Quality ◽  
Institutional Ownership ◽  
Institutional Investor ◽  
Short Term ◽  
Investor Attention ◽  
Bid Ask Spread ◽  
Abnormal Volume ◽  
Passive Investors ◽  
Jel Classifications

ABSTRACT We study how short-term changes in institutional owner attention affect managers' disclosure choices. Holding institutional ownership constant and controlling for industry-quarter effects, we find that managers respond to attention by increasing the number of forecasts and 8-K filings. Rather than alter the decision of whether to forecast or to provide more informative disclosures, attention causes minor disclosure adjustments. This variation in disclosure is primarily driven by passive investors. Although attention explains significant variation in the quantity of disclosure, we find little change in abnormal volume and volatility, the bid-ask spread, or depth. Overall, our evidence suggests that management responds to temporary institutional investor attention by making disclosures that have little effect on information quality or liquidity. JEL Classifications: G23; G32; G34; G12; G14.

Responses of lizards to three experiments fires in the savanna forests of Kakadu National Park

1994 ◽  
Vol 21 (2) ◽  
pp. 131 ◽  
Author(s):  
CR Trainor ◽  
JCZ Woinarski
Keyword(s):  
National Park ◽  
Habitat Type ◽  
Detrended Correspondence Analysis ◽  
Fire Regimes ◽  
Direct Effects ◽  
Short Term ◽  
Lizard Species ◽  
Savanna Communities ◽  
Induced Changes ◽  
Term Response

A species-rich lizard community responded variably to a range of experimental fire regimes in a tropical savanna. Heteronotia binoei was the only lizard species that showed a short-term response to fire, decreasing in abundance directly after the early- and late-burns. H. binoei and Diporiphora bilineata were significantly more abundant in early-burn treatments. Carlia amax was more abundant in unburnt and early-burn treatments. C. munda was more abundant in unburnt and early-burn sites. Differences in the relative abundance of species between treatments is attributed to site differences in vegetation structure, and fire-induced changes to the structure of habitat. Early-burn sites were significantly richer in lizard species (P< 0.05); however, overall lizard abundance, Shannon-Wiener diversity and Detrended Correspondence Analysis (DCA) 1 and DCA 2 scores were not significantly different, suggesting that habitat partitioning has a stronger influence than the direct effects of fire. Many lizards were associated with a direct gradient of moisture availability, including a seepage assemblage, with Carlia gracilis and Sphenomorphus darwiniensis correlated with increased moisture, a well-developed canopy and abundant leaf litter. An assemblage associated with the drier end of the gradient included Carlia triacantha, Ctenotus kurnbudj, Diporiphora magna and D. bilineata. The lizard composition of most quadrats was intermediate along the moisture gradient and was associated with typical eucalypt savanna communities. Lizard species that largely are restricted to the moist seepage zones may be particularly sensitive to late dry-season fires which alter this habitat type.

PECULIARITIES OF THE FLORISTIC COMPOSITION AND CHARACTER OF OVERGROWTH OF SMALL NON-FLOWING LAKES OF NARACH LAKE GROUP (BELARUS)

2021 ◽  
pp. 26-40
Author(s):  
A. Lapirov ◽  
E. Garin ◽  
E. Belyakov ◽  
A. Shestakova ◽  
O. Makarevich
Keyword(s):  
Plant Species ◽  
Vascular Plants ◽  
National Park ◽  
Trophic Status ◽  
Floristic Composition ◽  
Taxonomic Composition ◽  
Water Bodies ◽  
Annotated List ◽  
Liparis Loeselii ◽  
Isoetes Lacustris

The flora of small non-flowing lakes of the Narach lake group located on the territory of the Narachanski National Park (Belarus, Minsk region, Myadelsky district) was studied. The taxonomic composition of the flora numbering 126 species of vascular plants belonging to 85 genera from 42 families was revealed. Three plant species which are included in the list of protected taxa in Belarus were found – Liparis loeselii (L.) Rich. (Lake Shestakovo), Aldrovanda vesiculosa L. (Lake Shestakovo) and Isoëtes lacustris L. (Lake Beloe). Based on the annotated list of species presented in the work, taxonomic, geographical, ecological-coenotic and ecobiomorphological analyzes of the flora of water bodies were performed. According to the taxonomic and environmental structure, the flora of the studied lakes is shown to be traditional for this territory. The differences in the flora of the studied lakes are mainly due to their trophic status and, to a lesser extent, due to the diversity of biotopes and the nature of the anthropogenic load. Information on the nature of overgrowing of these water bodies is provided.

Adjacent pastoral areas support higher densities of wild ungulates during the wet season than the Lake Mburo National Park in Uganda

2006 ◽  
Vol 22 (6) ◽  
pp. 675-683 ◽  
Author(s):  
Ole Tobias Rannestad ◽  
Torbjørn Danielsen ◽  
Stein R. Moe ◽  
Sigbjørn Stokke
Keyword(s):  
Protected Areas ◽  
National Park ◽  
Distance Sampling ◽  
Sampling Technique ◽  
Total Density ◽  
Private Land ◽  
Wild Ungulates ◽  
Wet Season ◽  
Local Survival ◽  
Significant Difference

The small size of many African protected areas makes adjacent rangelands potentially important in the local survival of wild animals. In order to assess the importance of pastoral areas to wild ungulates, we studied density and habitat choice of wild ungulates and cattle in Lake Mburo National Park, Uganda, the adjacent exclusively pastoral Nshara Dairy Ranch and on private land consisting of a mixture of ranching and subsistence farms. Transects, in the three land-use zones, were walked during the wet season and the data were analysed by DISTANCE sampling technique. We found significantly higher total density of wild ungulates on the dairy ranch compared with the National Park and private land. There was no significant difference in total wild animal density between the National Park and private land. Impala (Aepyceros melampus), zebra (Equus quagga), bushbuck (Tragelaphus scriptus) and waterbuck (Kobus ellipsiprymnus) had significantly higher densities on the dairy ranch compared to the National Park. Only eland (Taurotragus oryx) density was higher in the National Park compared to private land. Wild ungulates and cattle showed a high degree of habitat overlap, generally preferring open grassland. Our study shows that high densities of wild ungulates are not necessarily associated with protected areas. Pastoral areas may be important for populations of wild herbivores during the growing season despite a pronounced presence of livestock.

Diurnal resting sites of the nocturnal dasyurid marsupial Sminthopsis douglasi in Bladensburg National Park, Queensland

2017 ◽  
Vol 39 (1) ◽  
pp. 121 ◽  
Author(s):  
P. A. Woolley
Keyword(s):  
National Park ◽  
Climatic Factors ◽  
Short Term ◽  
Term Study ◽  
Resting Sites ◽  
Short Term Study ◽  
Males And Females

An attempt has been made to determine where Julia Creek dunnarts (Sminthopsis douglasi), small nocturnal dasyurid marsupials, rest during the day under differing seasonal conditions. A short-term study was carried out in Bladensburg National Park, near the southern edge of its known distribution on the Mitchell grass downs in Queensland. Radio-collared individuals were located in cracks and holes. None of the males and females (including one with young in the pouch) were found to use the same resting site over periods of up to nine days, suggesting that they may be nomadic. Climatic factors may have affected the size of the dunnart population over the course of the study.

Sign in / Sign up

Export Citation Format

Share Document