scholarly journals Seasonal Fluctuations of Birds, Fruits, and Flowers in a Subtropical Forest of Argentina

The Condor ◽  
2001 ◽  
Vol 103 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Lucio R. Malizia
Keyword(s):  
Bird Community ◽  
Dry Season ◽  
Subtropical Forest ◽  
Seasonal Patterns ◽  
Monthly Variation ◽  
Conservation Priority ◽  
Seasonal Fluctuations ◽  
Wet Season ◽  
Disturbed Areas ◽  
Number Of Plant Species

AbstractI quantified monthly variation in species composition and captures of birds in a premontane forest of northwestern Argentina. Seasonal patterns of frugivore-insectivores and nectarivores were compared with fruit and flower abundances, respectively. The composition of the entire bird community fluctuated seasonally; frugivore-insectivores showed a peak in captures during the wet season, insectivores peaked at the end of the dry season, and nectarivores peaked during the dry season. At a local scale (∼50 ha), captures of frugivore-insectivores were not correlated with number of plant species with ripe fruits for any vegetation stratum considered, but were correlated with a fruit phenology index that considers crop size. At a plot scale (∼7.5 ha), only understory flower abundance and captures of nectarivores were correlated, but only in the plot where both were more abundant. At a net-site scale (50 m2), captures of the Rufous-bellied Thrush (Turdus rufiventris) were correlated with understory fruit abundance, but only in the plot where fruits were more abundant. These results suggest that seasonal fluctuations in birds may be driven to some extent by their food resources. Premontane forest provides habitat for many migrants and also presumably acts as a source of birds that emigrate to disturbed areas. Although premontane forests should be a conservation priority for the region, they are poorly protected and suffering high deforestation.

scholarly journals Environmental Determinants Influencing Seasonal Variations of Bird Diversity and Abundance in Wetlands, Northern Region (Ghana)

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Collins Ayine Nsor ◽  
Edward Adzesiwor Obodai
Keyword(s):  
Seasonal Variations ◽  
Bird Community ◽  
Iucn Red List ◽  
Northern Region ◽  
Dry Season ◽  
Bird Diversity ◽  
Environmental Determinants ◽  
Wet Season ◽  
Bird Abundance ◽  
Bubulcus Ibis

The study assessed major environmental determinants influencing bird community in six wetlands over a 2-year period. A combination of visual and bird sounding techniques was used to determine the seasonal variations in bird abundance, while ordination techniques were performed to determine the influence of environmental factors on bird assemblage. A total of 1,169 birds from 25 species and 885 individuals from 23 species were identified in the wet and dry season, respectively. The shallow close marshes supported the greatest number of birds (P<0.05) compared to the riparian wetlands. Bird diversity was significantly higher in the wet season than in the dry season (F=4.101,P<0.05). Cattle egret (Bubulcus ibis) and marsh warbler (Acrocephalus palustris) were the most abundant. Using the IUCN “Red List” database guide, we noted that 96.2% of birds identified were least concern (LC). The yellow weaver bird (Ploceous megarhrynchus) was the only vulnerable species (VU) and represented 3.8%. From the three variables tested, bushfire and farming practices were the major threats and cumulatively explained 15.93% (wet season) and 14.06% (dry season) variations in bird diversity and abundance. These findings will help wetland managers design conservation measures to check current threats on birds from becoming vulnerable in the future.

scholarly journals Soil nitrogen transformation responses to seasonal precipitation changes are regulated by changes in functional microbial abundance in a subtropical forest

2017 ◽  
Vol 14 (9) ◽  
pp. 2513-2525 ◽  
Author(s):  
Jie Chen ◽  
Guoliang Xiao ◽  
Yakov Kuzyakov ◽  
G. Darrel Jenerette ◽  
Ying Ma ◽  
...  
Keyword(s):  
N Mineralization ◽  
N2o Emission ◽  
Dry Season ◽  
Subtropical Forest ◽  
Microbial Abundance ◽  
Wet Season ◽  
N Transformations ◽  
Net Nitrification ◽  
N Transformation ◽  
Precipitation Changes

Abstract. The frequency of dry-season droughts and wet-season storms has been predicted to increase in subtropical areas in the coming decades. Since subtropical forest soils are significant sources of N2O and NO3−, it is important to understand the features and determinants of N transformation responses to the predicted precipitation changes. A precipitation manipulation field experiment was conducted in a subtropical forest to reduce dry-season precipitation and increase wet-season precipitation, with annual precipitation unchanged. Net N mineralization, net nitrification, N2O emission, nitrifying (bacterial and archaeal amoA) and denitrifying (nirK, nirS and nosZ) gene abundance, microbial biomass carbon (MBC), extractable organic carbon (EOC), NO3−, NH4+ and soil water content (SWC) were monitored to characterize and explain soil N transformation responses. Dry-season precipitation reduction decreased net nitrification and N mineralization rates by 13–20 %, while wet-season precipitation addition increased both rates by 50 %. More than 20 % of the total variation of net nitrification and N mineralization could be explained by microbial abundance and SWC. Notably, archaeal amoA abundance showed the strongest correlation with net N transformation rates (r  ≥  0.35), suggesting the critical role of archaeal amoA abundance in determining N transformations. Increased net nitrification in the wet season, together with large precipitation events, caused substantial NO3− losses via leaching. However, N2O emission decreased moderately in both dry and wet seasons due to changes in nosZ gene abundance, MBC, net nitrification and SWC (decreased by 10–21 %). We conclude that reducing dry-season precipitation and increasing wet-season precipitation affect soil N transformations through altering functional microbial abundance and MBC, which are further affected by changes in EOC and NH4+ availabilities.

scholarly journals Soil nitrogen transformation responses to seasonal precipitation changes are regulated by changes in functional microbial abundance in a subtropical forest

2017 ◽  
Author(s):  
Jie Chen ◽  
Guoliang Xiao ◽  
Yakov Kuzyakov ◽  
Darrel Jenerette ◽  
Ying Ma ◽  
...  
Keyword(s):  
N Mineralization ◽  
N2o Emission ◽  
Dry Season ◽  
Subtropical Forest ◽  
Net N Mineralization ◽  
Microbial Abundance ◽  
Wet Season ◽  
Net Nitrification ◽  
N Transformation ◽  
Precipitation Changes

Abstract. More dry-season droughts and wet-season storms have been predicted in subtropical areas. Since subtropical forest soils are significant sources of N2O and NO3−, it is important to understand the features and determinants of N transformation responses to the predicted precipitation changes. A precipitation manipulation field experiment was conducted to reduce dry-season precipitation and increase wet-season precipitation, while keeping the annual precipitation unchanged in a subtropical forest. Net N mineralization, net nitrification, N2O emission, nitrifying (bacterial and archaeal amoA) and denitrifying (nirK, nirS and nosZ) genes abundance, microbial biomass carbon (MBC) and soil physicochemical properties were monitored to characterize and explain soil N transformation responses. Dry-season precipitation reduction decreased net nitrification and N mineralization rates by 13–20 %, while wet-season precipitation addition increased both rates by 50 %. More than 20 % of the total variation of net nitrification and N mineralization could be explained by microbial abundance and soil water content (SWC), but archaeal amoA abundance was the main factor. Increased net nitrification in wet season together with large precipitation events caused substantial NO3− losses via leaching. However, N2O emission decreased moderately either in dry or wet seasons due to changes in nosZ gene abundance, MBC, net nitrification and SWC (decreased by 10–21 %). We conclude that reducing dry-season precipitation and increasing wet-season precipitation affect N transformation mainly through altering functional microbial abundance and MBC, which are further determined by changes in DOC and NH4+ availabilities. Such contrasting precipitation pattern will increase droughts and NO3− leaching in subtropical forests.

Ecology of Northern Australian Dacinae (Diptera: Tephritidae) II*. Seasonla Fluctuations in Trap Catches of Dacus opiliae and D. tenuifascia, and their Relationship to Host Phenology and Climatic Factors

1981 ◽  
Vol 29 (6) ◽  
pp. 885 ◽  
Author(s):  
GP Fitt
Keyword(s):  
Climatic Factors ◽  
Fruit Production ◽  
Dry Season ◽  
Methyl Eugenol ◽  
Northern Australia ◽  
Seasonal Fluctuations ◽  
Wet Season ◽  
Host Fruit ◽  
Temporal Aspects ◽  
Trap Catches

Changes in trap catches of male Dacus opiliae Drew & Hardy were studied in northern Australia by use of permanently maintained groups of Steiner traps baited with methyl eugenol, an attractant for males of this species. D. opiliae, which is monophagous on a wet-season host species, was common in traps from October to February (wet season) and rare for the remamder of the year. In a second species, D. tenuifascia (May), which is monophagous on a dry-season host, trap catches peaked during the period from August to October after commencement of host fruit production. D. tenuifascia was not absent from traps at any time of the year. Temporal aspects of the seasonal fluctuations of trap catches of D. opiliae could not be explained solely on the basis of increases due to reproduction. Other features, such as the disappearance of D. opiliae from mainland traps during the dry season, were also difficult to explain. It is concluded that changing dispersive behaviour and variable lure response of males. both controlled by environmental variables, may have strongly influenced the observed fluctuations.

Temporal and Spatial Variation in the Distribution and Abundance of the Magpie Goose, Anseranas semipalmata, in the Rockhampton Region of the Queensland Coast

1997 ◽  
Vol 24 (3) ◽  
pp. 347
Author(s):  
Robyn Wilson
Keyword(s):  
Spatial Variation ◽  
Open Water ◽  
Dry Season ◽  
Seasonal Fluctuations ◽  
Wet Season ◽  
Temporal And Spatial Variation ◽  
Cumulative Difference ◽  
Temporal And Spatial

The distribution, abundance and habitat of the magpie goose, Anseranas semipalmata, were studied from February 1987 to March 1990 and examined in relation to season, rainfall and evaporation, and the availability of sedges (Eleocharis spp.) in the Rockhampton area on the central Queensland coast. Seasonal fluctuations in abundance of the magpie goose were correlated with the 12-month cumulative difference between rainfall and evaporation in Rockhampton. Large flocks (>500 magpie geese) were observed on Eleocharis spp. and open water during the wet season, and on mud during the dry season.

scholarly journals The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xue Zhu ◽  
Jiyue Qin ◽  
Chongyang Tan ◽  
Kang Ning
Keyword(s):  
Gut Microbiome ◽  
Seasonal Changes ◽  
Dry Season ◽  
Urban Setting ◽  
Snp Analysis ◽  
Wet Season ◽  
Human Gut ◽  
Human Gut Microbiome ◽  
Genome Level ◽  
Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

scholarly journals Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann
Keyword(s):  
Air Temperature ◽  
Daily Rainfall ◽  
Climatic Conditions ◽  
Dry Season ◽  
Climate Impacts ◽  
Calling Behavior ◽  
Wet Season ◽  
Focal Species ◽  
Calling Activity ◽  
Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

scholarly journals Inorganic Nitrogen Production and Removal along the Sediment Gradient of a Stormwater Infiltration Basin

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett
Keyword(s):  
Removal Efficiency ◽  
N Mineralization ◽  
Inorganic Nitrogen ◽  
Dry Season ◽  
Pollutant Removal ◽  
Net N Mineralization ◽  
Wet Season ◽  
Inorganic N ◽  
N Removal ◽  
Stormwater Infiltration

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.

scholarly journals Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes

2012 ◽  
Vol 63 (9) ◽  
pp. 788 ◽  
Author(s):  
N. E. Pettit ◽  
T. D. Jardine ◽  
S. K. Hamilton ◽  
V. Sinnamon ◽  
D. Valdez ◽  
...  
Keyword(s):  
Water Quality ◽  
Seasonal Changes ◽  
Aquatic Macrophyte ◽  
Plant Cover ◽  
Critical Role ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Dry Tropics ◽  
The Impact

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.

Effects of moisture supply in the dry season and subsequent defoliation on persistence of the savanna grasses Themeda triandra, Heteropogon contortus and Panicum maximum

1992 ◽  
Vol 43 (2) ◽  
pp. 241 ◽  
Author(s):  
JJ Mott ◽  
MM Ludlow ◽  
JH Richards ◽  
AD Parsons
Keyword(s):  
Growing Season ◽  
Close Correlation ◽  
Dry Season ◽  
Carbon Gain ◽  
Panicum Maximum ◽  
Wet Season ◽  
Themeda Triandra ◽  
Heteropogon Contortus ◽  
Moisture Conditions ◽  
Sheath Material

The close correlation between grazing-induced mortality and major climatic patterns in Australian savannas, led us to the hypothesis that moisture conditions during the dry, non-growing season could affect sensitivity to grazing in the subsequent growing season. Using three widespread savanna species (Themeda triandra, Heteropogon contortus and Panicum maximum), this hypothesis was tested experimentally and the mechanisms controlling this response examined and quantified. In T. triandra drought during the dry season led to major mortality in defoliated plants in the next growing season. This mortality was caused by a synchrony of tillering at the commencement of the wet season, leaving few buds for replacement once parent tillers were killed by defoliation. T. triandra was also the most sensitive species to defoliation. This sensitivity was due to the poor ability of the plant to maintain positive carbon gain after defoliation. Several factors contributed to this poor ability, including: low total photosynthetic rate, low specific leaf area, and a large proportion of sheath material with poor photosynthetic capacity remaining after cutting. Both H. contortus and P. maximum growing under irrigated and fertilized conditions did not display any effects of previous moisture treatments when defoliated during the next wet season and were much less sensitive to defoliation than T. triandra.

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