Bimodal breeding seasonality of an understorey bird, Premnoplex brunnescens, in an Ecuadorian cloud forest

2010 ◽  
Vol 26 (5) ◽  
pp. 547-549 ◽  
Author(s):  
Harold F. Greeney
Keyword(s):  
Cloud Forest ◽  
Bird Species ◽  
Habitat Choice ◽  
Day Length ◽  
Slight Variation ◽  
Low Latitude ◽  
Tropical Regions ◽  
Complex Interactions ◽  
Breeding Seasonality ◽  
Foraging Movement

Despite the aseasonality of temperature and day length of many tropical regions, especially when compared with temperate latitudes, most tropical animals show fairly pronounced seasonal shifts in foraging, movement patterns and reproduction (Flecker & Feifarek 1994, Saul 1975, Wolda & Fisk 1981). Understanding reproductive seasonality in tropical avian communities involves distinguishing among complex interactions between weather, resource abundance, hormones, behaviour and other life-history traits (Wikelski et al. 2003). While there is a great deal of evidence that many tropical bird species breed seasonally (Hau 2001, Marchant 1959, Miller 1963, Snow & Snow 1964), we still understand little of the causes which drive observed patterns (Wikelski et al. 2003). Most studies which address the seasonality of reproduction in tropical birds have focused on locations with fairly extreme temporal changes in rainfall (Cruz & Andrews 1989, Lack 1950, Marchant 1959, Poulin et al. 1992, Voous 1950), and comparatively few have looked at relatively aseasonal low-latitude locations (Miller 1963, Moreau 1950). Similarly, though a few studies have pointed out slight variation in the within-species initiation of breeding based on microhabitat (Wikelski et al. 2003), we know very little about how micro-habitat choice for nesting may affect (or be affected by) breeding seasonality. In this study I describe the nesting cycle of the spotted barbtail (Premnoplex brunnescens), from the Ecuadorian Andes to better understand how reproduction may be seasonal when climatic cues are subtle or absent.

scholarly journals Evaluating the role of contracting and expanding rainforest in initiating cycles of speciation across the Isthmus of Panama

2012 ◽  
Vol 279 (1742) ◽  
pp. 3520-3526 ◽  
Author(s):  
Brian Tilston Smith ◽  
Amei Amei ◽  
John Klicka
Keyword(s):  
Bird Species ◽  
Tropical Regions ◽  
Isthmus Of Panama ◽  
Species Pairs ◽  
The Matrix ◽  
High Species Richness ◽  
The Rich ◽  
The Tropics ◽  
The Impact

Climatic and geological changes across time are presumed to have shaped the rich biodiversity of tropical regions. However, the impact climatic drying and subsequent tropical rainforest contraction had on speciation has been controversial because of inconsistent palaeoecological and genetic data. Despite the strong interest in examining the role of climatic change on speciation in the Neotropics there has been few comparative studies, particularly, those that include non-rainforest taxa. We used bird species that inhabit humid or dry habitats that dispersed across the Panamanian Isthmus to characterize temporal and spatial patterns of speciation across this barrier. Here, we show that these two assemblages of birds exhibit temporally different speciation time patterns that supports multiple cycles of speciation. Evidence for these cycles is further corroborated by the finding that both assemblages consist of ‘young’ and ‘old’ species, despite dry habitat species pairs being geographically more distant than pairs of humid habitat species. The matrix of humid and dry habitats in the tropics not only allows for the maintenance of high species richness, but additionally this study suggests that these environments may have promoted speciation. We conclude that differentially expanding and contracting distributions of dry and humid habitats was probably an important contributor to speciation in the tropics.

scholarly journals Reproductive biology of Macleania rupestris (Ericaceae), a pollen-limited Neotropical cloud-forest species in Costa Rica

2010 ◽  
Vol 26 (3) ◽  
pp. 351-354 ◽  
Author(s):  
Eric J. Fuchs ◽  
Jeffrey Ross-Ibarra ◽  
Gilbert Barrantes
Keyword(s):  
Costa Rica ◽  
Relative Humidity ◽  
Reproductive Success ◽  
Cloud Forest ◽  
Fruit Production ◽  
Foraging Activity ◽  
High Altitudes ◽  
Forest Species ◽  
Effective Time ◽  
Complex Interactions

The reproductive success of hummingbird-pollinated plants often depends on complex interactions between environmental conditions and pollinator biology (Navarro 1999, Stiles 1985, Wolf et al. 1976). The effect of environment on reproductive success of hummingbird-pollinated plants is particularly pronounced at high altitudes, where large daily fluctuations in temperature, relative humidity and solar radiation limit the effective time for photosynthesis (Cavieres et al. 2000) and affect foraging activity (Navarro 1999) and abundance of pollinators (Rahbek 1997). At high altitudes in the tropical cloud forests of Costa Rica these factors may have serious impacts on fruit production.

scholarly journals Bird richness and composition in a Cerrado fragment in the State of São Paulo

2010 ◽  
Vol 70 (2) ◽  
pp. 243-254 ◽  
Author(s):  
LT Manica ◽  
M Telles ◽  
MM Dias
Keyword(s):  
Conservation Status ◽  
Bird Species ◽  
Low Frequency ◽  
Bird Community ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Conservation Area ◽  
Tropical Regions ◽  
Bird Richness

Bird species richness is an important measure for monitoring biodiversity changes. We analysed avifauna richness and composition in a 472 ha protected cerrado fragment and surroundings at Fazenda Canchim (RL-CPPSE), São Carlos, in the State of São Paulo (SP). We carried out 95.1 hours of observation (22 visits) at irregular intervals from May 2004 to December 2006. Qualitative surveys were done walking through tracks inside the fragment and on the roads at its edge. We recorded 160 species, six of which were endemic to Cerrado domain, 22 migratory, seven threatened within the State of São Paulo, and two globally threatened. We found 28 species in the cerradão, 110 in the cerrado sensu stricto, 13 in the gallery forest, 26 in the reservoir border, 26 in pasturelands and sugar cane monoculture and 55 in an anthropic area. Most of the species had low frequency of occurrence in all vegetation forms. Insectivores were the major trophic category (46.9%), which is typical in tropical regions, and it is also related to resource availability. Omnivores followed with 19.4%, granivores with 8.8% and frugivores with 7.5%. We conclude that, despite its size and conservation status, our study area has a remarkable bird community and must be considered as a priority conservation area to preserve bird species in Sao Paulo State.

Diet and Breeding Seasonality among a Population of Sharp-Tailed Munias, Lonchura striata, in Malaysia

The Auk ◽  
1980 ◽  
Vol 97 (1) ◽  
pp. 160-166
Author(s):  
Michael L. Avery
Keyword(s):  
Food Habits ◽  
Bird Species ◽  
Reproductive Activity ◽  
Peninsular Malaysia ◽  
Rice Cultivation ◽  
Filamentous Alga ◽  
Field Observations ◽  
Insect Abundance ◽  
Breeding Seasonality ◽  
Natural Cycles

Abstract From April 1975 through March 1977, the food habits and breeding seasonality of a population of Sharp-tailed Munias (Lonchura striata) were studied in northwestern peninsular Malaysia. The abundance of munias on the study area varied in accordance with the 6-month rice-growing cycle there. The population peaked in March and September when juvenile birds were most numerous and when rice was most plentiful. Field observations and stomach analyses showed that the munias ate rice and the green filamentous alga, Spirogyra, almost exclusively. The primary periods of algae eating occurred in January and June-August, coinciding with the munias' two peak periods of reproductive activity, as determined by gonadal examination. Apparently munias on the study area ate Spirogyra as a source of protein to enable them to become physiologically ready for breeding, much as othe tropical bird species eat insects. Thus, unlike other species, Sharp-tailed Munias' breeding seasonality is determined by manmade cycles of rice cultivation rather than by natural cycles of rain and insect abundance.

Seasonality, the latitudinal gradient of diversity, and Eocene insects

Paleobiology ◽  
2010 ◽  
Vol 36 (3) ◽  
pp. 374-398 ◽  
Author(s):  
S. Bruce Archibald ◽  
William H. Bossert ◽  
David R. Greenwood ◽  
Brian D. Farrell
Keyword(s):  
Species Diversity ◽  
Modern World ◽  
Low Latitude ◽  
Tropical Regions ◽  
La Selva ◽  
Harvard Forest ◽  
Diversity Gradient ◽  
Biotic Diversity ◽  
High Species Richness ◽  
Temperature Seasonality

In the modern world, biotic diversity is typically higher in low-latitude tropical regions where there is abundant insolation (light and heat) and low thermal seasonality. Because these factors broadly covary with latitude, separating their possible effects on species diversity is difficult. The Eocene was a much more equable world, however, with low temperature seasonality extending into lower-insolation higher, cooler latitudes, allowing us to test these factors by comparing insect species diversity in (1) modern, temperate, low-insolation, highly seasonal Harvard Forest, Massachusetts, U.S.A., 42°29'N; (2) modern, tropical, high-insolation, low-seasonality La Selva, Costa Rica, 10°26'N, and; (3) Eocene, temperate, low-insolation, yet low-seasonality McAbee, British Columbia, Canada, above 50°N paleolatitude. We found insect diversity at McAbee to be more similar to La Selva than to Harvard Forest, with high species richness of most groups and decreased diversity of ichneumon wasps, indicating that seasonality is key to the latitudinal diversity gradient. Further, midlatitude Eocene woody dicot diversities at McAbee, Republic (Washington, U.S.A.), and Laguna del Hunco (Argentina) are also high, similar to modern tropical samples, higher than at the modern midlatitude Harvard Forest. Modern correlations between latitude, species diversity, and seasonal climates were established some time after the Eocene.

Into the Evening: Complex Interactions in the Arabidopsis circadian clock

2016 ◽  
Author(s):  
He Huang ◽  
Dmitri A. Nusinow
Keyword(s):  
Arabidopsis Thaliana ◽  
Circadian Clock ◽  
Growth And Development ◽  
Clock Genes ◽  
Day Length ◽  
Interacting Proteins ◽  
Plant Growth And Development ◽  
Complex Interactions ◽  
New Findings ◽  
Direct Regulation

AbstractIn Arabidopsis thaliana, an assembly of proteins named the evening complex (EC) has been established as an essential component of the circadian clock with conserved functions in regulating plant growth and development. Recent studies identifying EC-regulated genes and EC-interacting proteins have expanded our understanding of EC function. In this review, we focus on new progress uncovering how the EC contributes to the circadian network through the integration of environmental inputs and the direct regulation of key clock genes. We also summarize new findings of how the EC directly regulates clock outputs, such as day-length dependent and thermoresponsive growth, and provide new perspectives on future experiments to address unsolved questions related to the EC.

scholarly journals Global hotspots of recent and ancestral turnover in birds

2020 ◽  
Author(s):  
Ian R. McFadden ◽  
Marco Túlio P. Coelho ◽  
Rafael O. Wüest ◽  
Fernanda A. S. Cassemiro ◽  
Niklaus E. Zimmermann ◽  
...  
Keyword(s):  
Bird Species ◽  
Global Scale ◽  
Climatic Variation ◽  
Future Research ◽  
Niche Conservatism ◽  
Tropical Regions ◽  
Tropical Mountains ◽  
Biodiversity Research ◽  
Relative Contribution ◽  
Ancient Lineage

Abstract A primary goal of biodiversity research is to uncover the processes acting in space and time to create the global distribution of species richness. However, we currently lack an understanding of how recent versus ancient biodiversity dynamics shape patterns of diversity for most groups. Here, we introduce a method to partition lineage turnover into recent and ancestral components, and use it to identify hotspots of turnover at the global scale for 8,296 bird species. Counter to the tropical niche conservatism hypothesis, we find extra-tropical regions such as Greenland and the Sahara are hotspots of ancestral turnover, while areas with high climatic variation such as (sub)tropical mountains and biome transitions are recent turnover hotspots. We can now quantify the relative contribution of contemporary and ancient lineage dynamics to assemblage structure, which enables future research to explore the processes generating earth’s diversity in a more temporally-explicit framework.

Density Trends and Range Boundary Constraints of Forest Birds Along a Latitudinal Gradient

The Auk ◽  
1986 ◽  
Vol 103 (4) ◽  
pp. 791-803 ◽  
Author(s):  
John T. Emlen ◽  
Michael J. DeJong ◽  
Michael John Jaeger ◽  
Timothy C. Moermond ◽  
Kurt A. Rusterholz ◽  
...  
Keyword(s):  
Habitat Structure ◽  
Deciduous Forest ◽  
Climatic Factors ◽  
Environmental Gradients ◽  
Species Abundance ◽  
Bird Species ◽  
Population Data ◽  
Day Length ◽  
Latitudinal Gradients ◽  
Habitat Factors

Abstract We plotted the density distributions of 41 land-bird species along a 1,200-km transect spanning 7°28′ (865 km) of latitude through relatively uniform bottomland deciduous forest in middle North America. Standardized counts and observations at 12 survey stations, closely matched in habitat structure and widely distributed along the route, provided population data for all species and indices of total avian foraging pressure (consuming biomass) on each of six major foraging substrates. Density curves for species fluctuated considerably from station to station but tended to be level across range centers and slope peripherally to north and south boundaries at rates of 3-30% per degree of latitude. Substrate foraging pressures declined northward on the aerial and midfoliage substrates and southward on the low-foliage substrate. Summed community densities showed no significant latitudinal trends. We used the distinctive distribution patterns of climate (smooth latitudinal gradients), habitat structure (irregular mosaics of vegetation patches), and competition (reciprocally sloping density gradients) to identify and evaluate the role of these three constraints along the transect. Progressive latitudinal trends in species abundance thus were attributed to climatic factors, irregular station-to-station fluctuations to habitat factors, and inversely sloping density trends in paired profiles to competition. On this basis all species apparently responded to both climatic and habitat factors, and about half of the species showed suggestions of competition. In a correlation analysis across the 12 stations, latitude per se most closely matched density distribution in 12 species, one or another of the habitat parameters in 25 species. We proposed that season length (days available for breeding activity) was the principal constraining attribute of latitude at northern range boundaries, day length (hours available for feeding and provisioning young) at southern boundaries. Boundaries have been essentially stable during the past 50-100 yr in most species, but the northern boundary expanded northward in one species following human-induced habitat enhancement, and temporarily receded southward in another following a winter of severe stress. We attribute this general stability of range boundaries over time to within-population gene flow and the associated peripherally declining mean fitness of phenotypes adapted to central range conditions along radially diverging environmental gradients. We suggest that two boundary lines should be recognized for each species, an inner functional boundary at the line where birth rates drop below death rates, and an outer empirical boundary at the limit of recorded occurrences.

The Acceptance of Dyed Grain by Feral Pigs and Birds. 3. Comparison of Intakes of Dyed and Undyed Grain by Feral Pigs and Birds in Pig-Proof Paddocks.

1985 ◽  
Vol 12 (3) ◽  
pp. 447 ◽  
Author(s):  
J Hone ◽  
H Bryant ◽  
P Nicholls ◽  
W Atkinson ◽  
R Kleba
Keyword(s):  
Bird Species ◽  
Blue Dye ◽  
Feral Pigs ◽  
Complex Interactions ◽  
Sorghum Grains ◽  
Feral Pig

In a 2-year study maize, wheat and sorghum grains, and a green and a blue dye were used. Of 57 bird species recorded in the study area only galahs and crested pigeons were observed eating grain. Neither feral pigs nor birds had differences in intake of undyed or dyed grain on average over the study; however, intake differences were highly variable as a result of interactions involving years, seasons, grains and times within seasons. Daily grain intake per pig averaged 2.33 kg and daily grain intake by all birds averaged 0.24 kg. Intakes by pigs and birds varied significantly with years, seasons, grains and times within seasons in complex interactions. The study suggests that poisoned grain baits for feral pig control may be dyed with little effect on intake by feral pigs, but that dyeing poisoned grain may not decrease its acceptance by some bird species.

scholarly journals Restricted movements and high site fidelity in three East African cloud-forest birds

2015 ◽  
Vol 32 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Jan Christian Habel ◽  
Jessica Hillen ◽  
Thomas Schmitt ◽  
Christina Fischer
Keyword(s):  
Sedentary Behaviour ◽  
Site Fidelity ◽  
Cloud Forest ◽  
Bird Species ◽  
Passerine Bird ◽  
Home Ranges ◽  
East African ◽  
Forest Patch ◽  
High Site ◽  
The Tropics

Abstract:Species with specific habitat requirements often remain within their habitat and are characterized by a very sedentary behaviour. We used radio-tracking during a 3-wk campaign to investigate the home ranges and movements of three East African passerine bird species, all adapted to cloud-forest habitats: montane white-eye Zosterops poliogaster mbuluensis, stripe-cheeked greenbul Andropadus milanjensis and white-starred robin Pogonocichla stellata macarthuri. Individuals were observed in a forest-grassland mosaic on top of Chyulu Hills, south Kenya. Based on 15 individuals with a total of 1041 fixes, we found (1) that all three species show a sedentary behaviour restricted to their home forest patch; (2) least activity during the afternoon; and (3) re-colonization into its home patch after translocation into a nearby forest patch. Our findings underline that forest-specialist bird species of the tropics show high site fidelity despite their potential movement ability.

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