scholarly journals Habitat requirements and population estimate of the endangered Ecuadorian Tapaculo Scytalopus robbinsi

2017 ◽  
Vol 28 (2) ◽  
pp. 302-318 ◽  
Author(s):  
CLAUDIA HERMES ◽  
JEROEN JANSEN ◽  
H. MARTIN SCHAEFER
Keyword(s):  
Habitat Requirements ◽  
Habitat Availability ◽  
Secondary Forests ◽  
Forest Fragments ◽  
Mobile Species ◽  
The Mean ◽  
Microhabitat Structure ◽  
The Tropics ◽  
Global Population ◽  
Population Numbers

SummaryThe Chocó-Tumbesian region of western Ecuador is one of the 25 global biodiversity hotspots harbouring high numbers of endemic species, which are heavily threatened by habitat loss and fragmentation. Moreover, ongoing climate change in the tropics drives species uphill as lower-lying areas are becoming constantly drier. Such upslope movement can pose major challenges for less mobile species, such as understorey birds which are confined to mature forests and unable to cross habitat gaps. Consequently, these species are threatened by a combination of upslope range shifts and forest fragmentation. In our study, we investigated population numbers and habitat requirements of the Ecuadorian Tapaculo Scytalopus robbinsi, which is endemic to the premontane cloud forests of south-western Ecuador. Comparing the microhabitat structure within territories with control sites revealed that Ecuadorian Tapaculos prefer old secondary forests. Moreover, connectivity between forest fragments was the strongest predictor of the presence of territories within them. We estimated the mean upslope shift of the distribution range as 100 m per decade and developed a model of habitat availability for the revised range. Extrapolating the number of territories from the study area to the distributional range of the Ecuadorian Tapaculo showed that the global population size is smaller than previously assumed. Our results suggest that the Ecuadorian Tapaculo is strongly affected by forest loss and degradation. Therefore, to prevent a continuing decline in population numbers or even extinction, conservation measures focusing on restoring connectivity between fragments and increasing habitat quality and quantity for the remaining populations need to be prioritised.

Bewirtschaftung von tropischen Sekundärwäldern

2002 ◽  
Vol 46 (1) ◽  
Author(s):  
Dietrich Schmidt-Vogt
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Stand Structure ◽  
Secondary Forest ◽  
Secondary Forests ◽  
Tropical Asia ◽  
Land Use Systems ◽  
The Future ◽  
The Tropics ◽  
Primary Forests

AbstractManagement of secondary tropical forests: a new perspective for sustainable use of forests in Asia. The decline of primary forests in the tropics is leading to a reassessment of the role secondary forests might play within the context of tropical forest management. Recent research has shown that secondary forests in the tropics can be both rich in species and complex in terms of stand structure. There is, moreover, a growing recognition of the importance of secondary forests for traditional subsistence economies in the tropics and of their economic potential for land use systems in the future. Management of secondary forests in Asia as an alternative to the extraction of timber from primary forests but also as one among other options to intensify traditional land use systems has a potential for the future especially because of the existence of vast tracts of valuable secondary forest cover, and because of the store of traditional knowledge that can still be found in tropical Asia.

The composition of milk of British Alpine and Anglo–Nubian goats imported into Trinidad

1972 ◽  
Vol 39 (3) ◽  
pp. 381-385 ◽  
Author(s):  
C. Devendra
Keyword(s):  
Milk Composition ◽  
Pennisetum Purpureum ◽  
Dairy Goats ◽  
Mineral Contents ◽  
Total N ◽  
Total Solids ◽  
Concentrate Mixture ◽  
The Mean ◽  
Inadequate Nutrition ◽  
The Tropics

SummaryThe variations in the composition of milk over an 18-week period from lactating British Alpine and Anglo–Nubian goats imported into Trinidad are reported. The animals were fed Napier grass (Pennisetum purpureum) ad lib. and 2 lb of a proprietary concentrate mixture daily.The mean percentage contents of the milks of British Alpine and Anglo–Nubian goats were: total solids 11·49±0·22, 12·17±0·28; butterfat 3·42±0·18, 4·06±0·22; total N 0·462±0·04, 0·530±0·07; ash 0·78±0·02, 0·79±0·03 and ‘lactose’ 4·38±0·28, 4·05±0·55. Anglo–Nubian goats had a higher content of percentage total solids, fat, total N and ash. For all constituents the coefficient of variation between weeks was higher for Anglo–Nubian goats. No significant trends were found between weeks for each of the components analysed for both breeds. Statistically significant correlations (P < 0·01) were found between percentage fat and percentage total N for both breeds.The mean mineral contents (mg/100ml) for the milks of British Alpine and Anglo–Nubian goats were: Na 52·6±4·6, 55·5±1·9; K164·0±8·4, 133·4±11·4; Ca 85·5±11·6, 89·9±9·8; Mg 13·2±3·8, 10·2±1·6 and P 74·7±3·9, 82·1±3·9. British Alpine goat's milk had a higher content of K and that of Anglo–Nubian goats had a higher content of P; both differences were statistically significant (P < 0·01).The milk composition figures in this study together with those from a similar study in Guadeloupe suggest that the values are low and considerably lower in comparison with the same breeds of goats in a temperate environment. This could be a feature of dairy goats imported into the tropics due perhaps to inadequate nutrition. Much more information is needed to verify this possibility.

Forest fragments, primary and secondary forests harbour similar arthropod assemblages after 40 years of landscape regeneration in the Central Amazon

2021 ◽  
Author(s):  
Karina Kethelen Silva De Aquino ◽  
Fabricio Beggiato Baccaro ◽  
Giulliana Appel ◽  
Augusto Loureiro Henriques ◽  
Paulo Estefano Dineli Bobrowiec ◽  
...  
Keyword(s):  
Secondary Forests ◽  
Forest Fragments ◽  
Central Amazon

Assessing the sustainability of yellow anaconda (Eunectes notaeus) harvest in northeastern Argentina

2020 ◽  
Author(s):  
Bruno Camera ◽  
Christine Stüssmann ◽  
Itxaso Quintana ◽  
Tomás Waller ◽  
Mariano Barros ◽  
...  
Keyword(s):  
Wildlife Management ◽  
Sustainable Use ◽  
Management Program ◽  
Gradual Reduction ◽  
Hunting Season ◽  
Time Period ◽  
History Of ◽  
The Mean ◽  
The Tropics ◽  
Northeastern Argentina

Abstract Sustainable wildlife management is required to guarantee source species viability; however, it is practiced rarely in the tropics. The yellow anaconda (Eunectes notaeus) has a long history of being harvested for its leather. Since 2002 its harvest has operated under a management program in northeastern Argentina, which relies on adaptive management through limiting the minimum anaconda length, number of hunters and restricting the hunting season. We investigated the effects of the anaconda harvest on its biological parameters based on 2002-2016 data. Here we show that the levels of species exploitation are sustainable. The gradual reduction in the annual hunting effort, due to a decrease in number of hunters and hunting season duration, reduced the total number of anacondas harvested. Conversely, captures per unit effort increased across the study time-period. There was no variation in the mean length of anacondas harvested, or in largest anaconda sizes. Though more females than males were caught, the sex ratio did not vary significantly. We also found that a decrease in mean temperature positively influenced anaconda harvest and the captures of giant individuals. Because sustainable use is a powerful tool for conservation, those discoveries are highly applicable to other species and regions.

scholarly journals Variability and quasi-decadal changes in the methane budget over the period 2000–2012

2017 ◽  
Author(s):  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Benjamin Poulter ◽  
Anna Peregon ◽  
Philippe Ciais ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Methane Emissions ◽  
Data Driven ◽  
Atmospheric Methane ◽  
Top Down ◽  
Bottom Up ◽  
Ch4 Emissions ◽  
Ensemble Mean ◽  
The Mean ◽  
The Tropics

Abstract. Following the recent Global Carbon project (GCP) synthesis of the decadal methane (CH4) budget over 2000–2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling frameworks) and bottom-up models, inventories, and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven extrapolations). The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000–2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000–2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008–2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16–32] Tg CH4 yr−1 higher methane emissions over the period 2008–2012 compared to 2002–2006. This emission increase mostly originated from the tropics with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seems to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002–2006 and 2008–2012 differs from one atmospheric inversion study to another. However, all top-down studies suggest smaller changes in fossil fuel emissions (from oil, gas, and coal industries) compared to the mean of the bottom-up inventories included in this study. This difference is partly driven by a smaller emission change in China from the top-down studies compared to the estimate in the EDGARv4.2 inventory, which should be revised to smaller values in a near future. Though the sectorial partitioning of six individual top-down studies out of eight are not consistent with the observed change in atmospheric 13CH4, the partitioning derived from the ensemble mean is consistent with this isotopic constraint. At the global scale, the top-down ensemble mean suggests that, the dominant contribution to the resumed atmospheric CH4 growth after 2006 comes from microbial sources (more from agriculture and waste sectors than from natural wetlands), with an uncertain but smaller contribution from fossil CH4 emissions. Besides, a decrease in biomass burning emissions (in agreement with the biomass burning emission databases) makes the balance of sources consistent with atmospheric 13CH4 observations. The methane loss (in particular through OH oxidation) has not been investigated in detail in this study, although it may play a significant role in the recent atmospheric methane changes.

scholarly journals The context of the size and distance of Atlantic Forest fragments in a small city in Southern Brazil

2019 ◽  
Vol 41 ◽  
pp. e46936
Author(s):  
Matheus Bueno Patrício ◽  
José Hilário Delconte Ferreira ◽  
Edivando Vitor do Couto
Keyword(s):  
Atlantic Forest ◽  
Nearest Neighbor ◽  
Diversity Index ◽  
Area Ratio ◽  
Native Vegetation ◽  
Small City ◽  
Forest Fragments ◽  
Forest Remnants ◽  
Significant Area ◽  
The Mean

The Atlantic Forest is highly anthropized, this reduce the areas of native vegetation and impacts the biodiversity of the biome. The objective of this study is to analyze forest remnants with native vegetation characteristics using a free GIS. This analysis takes place using landscape metrics and was based on the supervised vectorization of land use in the municipality of California, PR. The area of the vectored polygons was obtained and a classified, and then the calculation was made with the nearest neighbor index, mean distance observed, Patton diversity index and the perimeter/area ratio of forest fragments. The results show that most of the fragments have an area smaller than 1 ha, the fragments with more significant area (<50 ha) represent more than 16% of the native vegetation area. The small fragments are important to maintain the connectivity, since the withdrawal of these increases the mean distance observed and nearest neighbor index. Most of the fragments are elongated and amorphous in accordance with the perimeter/area ratio and the Patton diversity index respectively, this may demonstrate the fragments may be subject to edge effects. Even with these characteristics, these fragments may be part of what is planned in public policy for preservation in the Atlantic Forest in the state of Paraná. Therefore, even small fragments with little core area are important for maintaining biodiversity, especially in a highly anthropogenic landscape

scholarly journals A Multidiagnostic Intercomparison of Tropical-Width Time Series Using Reanalyses and Satellite Observations

2012 ◽  
Vol 25 (4) ◽  
pp. 1061-1078 ◽  
Author(s):  
Sean M. Davis ◽  
Karen H. Rosenlof
Keyword(s):  
Longwave Radiation ◽  
Hadley Cell ◽  
Radiosonde Data ◽  
Full Time ◽  
Robust Detection ◽  
Time Period ◽  
Wide Range ◽  
The Mean ◽  
Yield Trends ◽  
The Tropics

Abstract Poleward migration of the latitudinal edge of the tropics of 0.25°–3.0° decade−1 has been reported in several recent studies based on satellite and radiosonde data and reanalysis output covering the past ~30 yr. The goal of this paper is to identify the extent to which this large range of trends can be explained by the use of different data sources, time periods, and edge definitions, as well as how the widening varies as a function of hemisphere and season. Toward this end, a suite of tropical edge latitude diagnostics based on tropopause height, winds, precipitation–evaporation, and outgoing longwave radiation (OLR) are analyzed using several reanalyses and satellite datasets. These diagnostics include both previously used definitions and new definitions designed for more robust detection. The wide range of widening trends is shown to be primarily due to the use of different datasets and edge definitions and only secondarily due to varying start–end dates. This study also shows that the large trends (&gt;~1° decade−1) previously reported in tropopause and OLR diagnostics are due to the use of subjective definitions based on absolute thresholds. Statistically significant Hadley cell expansion based on the mean meridional streamfunction of 1.0°–1.5° decade−1 is found in three of four reanalyses that cover the full time period (1979–2009), whereas other diagnostics yield trends of −0.5°–0.8° decade−1 that are mostly insignificant. There are indications of hemispheric and seasonal differences in the trends, but the differences are not statistically significant.

scholarly journals Net effect of the QBO in a chemistry climate model

2008 ◽  
Vol 8 (21) ◽  
pp. 6505-6525 ◽  
Author(s):  
H. J. Punge ◽  
M. A. Giorgetta
Keyword(s):  
General Circulation ◽  
Climate Models ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Meridional Circulation ◽  
Vortex Formation ◽  
General Circulation Models ◽  
Quasi Biennial Oscillation ◽  
The Mean ◽  
The Tropics

Abstract. The quasi-biennial oscillation (QBO) of zonal wind is a prominent mode of variability in the tropical stratosphere. It affects not only the meridional circulation and temperature over a wide latitude range but also the transport and chemistry of trace gases such as ozone. Compared to a QBO less circulation, the long-term climatological means of these quantities are also different. These climatological net effects of the QBO can be studied in general circulation models that extend into the middle atmosphere and have a chemistry and transport component, so-called Chemistry Climate Models (CCMs). In this work we show that the CCM MAECHAM4-CHEM can reproduce the observed QBO variations in temperature and ozone mole fractions when nudged towards observed winds. In particular, it is shown that the QBO signal in transport of nitrogen oxides NOx plays an important role in reproducing the observed ozone QBO, which features a phase reversal slightly below the level of maximum of the ozone mole fraction in the tropics. We then compare two 20-year experiments with the MAECHAM4-CHEM model that differ by including or not including the QBO. The mean wind fields differ between the two model runs, especially during summer and fall seasons in both hemispheres. The differences in the wind field lead to differences in the meridional circulation, by the same mechanism that causes the QBO's secondary meridional circulation, and thereby affect mean temperatures and the mean transport of tracers. In the tropics, the net effect on ozone is mostly due to net differences in upwelling and, higher up, the associated temperature change. We show that a net surplus of up to 15% in NOx in the tropics above 10 hPa in the experiment that includes the QBO does not lead to significantly different volume mixing ratios of ozone. We also note a slight increase in the southern vortex strength as well as earlier vortex formation in northern winter. Polar temperatures differ accordingly. Differences in the strength of the Brewer-Dobson circulation and in further trace gas concentrations are analysed. Our findings underline the importance of a representation of the QBO in CCMs.

Production of the Euphausiid Crustacean Thysanoëssa raschii in the Gulf of St. Lawrence

1977 ◽  
Vol 34 (3) ◽  
pp. 443-446 ◽  
Author(s):  
F. Berkes
Keyword(s):  
Field Data ◽  
Zooplankton Biomass ◽  
Total Zooplankton ◽  
Loss Of Weight ◽  
Annual Biomass ◽  
The Mean ◽  
Total Zooplankton Biomass ◽  
Population Numbers

From field data on growth and population numbers, production of Thysanoëssa raschii, excluding molts, was calculated to be about 1.8 mg dry wt∙m−3∙yr−1 in the Gulf of St. Lawrence. The mean annual biomass of T. raschii was 0.47 mg dry wt∙m−3, comprising about 1% of the total zooplankton biomass in the Gulf, and giving a production to biomass (P:B) ratio of about 4. Production and biomass were probably underestimated due to some sampler avoidance, lack of egg to nauplius–metanauplius interval of population production and loss of weight due to leaching in preserved samples.

scholarly journals Spatial and temporal variability of interhemispheric transport times

2018 ◽  
Vol 18 (10) ◽  
pp. 7439-7452 ◽  
Author(s):  
Xiaokang Wu ◽  
Huang Yang ◽  
Darryn W. Waugh ◽  
Clara Orbe ◽  
Simone Tilmes ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Mean Transit Time ◽  
Intertropical Convergence Zone ◽  
Spatial And Temporal Variability ◽  
Rapid Loss ◽  
Seasonal And Interannual Variability ◽  
Transit Times ◽  
The Mean ◽  
The Tropics ◽  
Interhemispheric Transport

Abstract. The seasonal and interannual variability of transport times from the northern midlatitude surface into the Southern Hemisphere is examined using simulations of three idealized “age” tracers: an ideal age tracer that yields the mean transit time from northern midlatitudes and two tracers with uniform 50- and 5-day decay. For all tracers the largest seasonal and interannual variability occurs near the surface within the tropics and is generally closely coupled to movement of the Intertropical Convergence Zone (ITCZ). There are, however, notable differences in variability between the different tracers. The largest seasonal and interannual variability in the mean age is generally confined to latitudes spanning the ITCZ, with very weak variability in the southern extratropics. In contrast, for tracers subject to spatially uniform exponential loss the peak variability tends to be south of the ITCZ, and there is a smaller contrast between tropical and extratropical variability. These differences in variability occur because the distribution of transit times from northern midlatitudes is very broad and tracers with more rapid loss are more sensitive to changes in fast transit times than the mean age tracer. These simulations suggest that the seasonal–interannual variability in the southern extratropics of trace gases with predominantly NH midlatitude sources may differ depending on the gases' chemical lifetimes.

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