Low bee visitation rates explain pollinator shifts to vertebrates in tropical mountains

2021 ◽  
Author(s):  
Agnes S. Dellinger ◽  
Rocio Pérez‐Barrales ◽  
Fabián A. Michelangeli ◽  
Darin S. Penneys ◽  
Diana M. Fernández‐Fernández ◽  
...  
Keyword(s):  
Tropical Mountains ◽  
Visitation Rates

DUELING EROSION FRONTS: GLACIAL BUZZCUTTING AND NONGLACIAL SCARP ENCROACHMENT LIMIT THE HEIGHT OF TROPICAL MOUNTAINS

2016 ◽  
Author(s):  
Maxwell Cunningham ◽  
◽  
Colin Stark ◽  
Michael R. Kaplan ◽  
Joerg M. Schaefer
Keyword(s):  
Tropical Mountains

Solar Ultraviolet on Tropical Mountains: Can It Affect Plant Speciation?

1980 ◽  
Vol 115 (6) ◽  
pp. 880-883 ◽  
Author(s):  
David W. Lee ◽  
J. Brian Lowry
Keyword(s):  
Tropical Mountains ◽  
Solar Ultraviolet

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

scholarly journals Impact of Weed Control by Hand Tools on Soil Erosion under a No-Tillage System Cultivation

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 974
Author(s):  
Rafael Blanco-Sepúlveda ◽  
Amilcar Aguilar-Carrillo ◽  
Francisco Lima
Keyword(s):  
Soil Erosion ◽  
Weed Control ◽  
Soil Cover ◽  
Soil Surface ◽  
Conservation Agriculture ◽  
Soil Disturbance ◽  
No Tillage ◽  
Tropical Mountains ◽  
Litter Cover ◽  
Vegetal Cover

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.

Changes in the behaviour ofOcypode quadrata(Fabricius, 1787) after experimental trampling

2018 ◽  
Vol 99 (5) ◽  
pp. 1135-1140 ◽  
Author(s):  
Leonardo Lopes Costa ◽  
Julyana Figueiredo Madureira ◽  
Ilana Rosental Zalmon
Keyword(s):  
Surface Activity ◽  
Sampling Design ◽  
Lower Surface ◽  
Sandy Beaches ◽  
Controlled Experiment ◽  
Visitation Rates ◽  
Ghost Crabs ◽  
Before And After

AbstractThe effects of trampling are usually confounded by the diffuse impacts of the urbanization of sandy beaches. We performed a controlled experiment on a beach with low visitation rates to test the hypothesis that ghost crabs avoid building their burrows on impacted plots as a result of the compacted sediment, and they migrate to non-trampled areas. The sampling design encompassed 11 survey quadrats (6 × 6 m) above the strandline, including five trampled plots (100, 300, 900, 1500 and 3000 steps) and six non-trampled plots. The plots were sampled before and after 24, 48 and 72 h of experimental trampling. We found that the ghost crabs avoided building their burrows in only the 1500× and 3000× trampled plots after 24 h, but the avoidance was not related to sediment compactness. Additionally, the emersion time and escape distance from humans were significantly delayed in the most trampled plots, suggesting a lower surface activity and an avoidance of irregular (i.e. high micro-relief) sediment surfaces by ghost crabs, which might reduce their ability to perceive potential predators.

scholarly journals Mountain colonisation, miniaturisation and ecological evolution in a radiation of direct-developing New Guinea Frogs (Choerophryne, Microhylidae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3077 ◽  
Author(s):  
Paul M. Oliver ◽  
Amy Iannella ◽  
Stephen J. Richards ◽  
Michael S.Y. Lee
Keyword(s):  
Body Size ◽  
Small Body ◽  
Strong Support ◽  
New Guinea ◽  
Ancestral State ◽  
Tropical Mountains ◽  
Climatic Oscillations ◽  
Evolutionary Trajectories ◽  
Montane Biodiversity ◽  
Male Calling

AimsMountain ranges in the tropics are characterised by high levels of localised endemism, often-aberrant evolutionary trajectories, and some of the world’s most diverse regional biotas. Here we investigate the evolution of montane endemism, ecology and body size in a clade of direct-developing frogs (Choerophryne,Microhylidae) from New Guinea.MethodsPhylogenetic relationships were estimated from a mitochondrial molecular dataset using Bayesian and maximum likelihood approaches. Ancestral state reconstruction was used to infer the evolution of elevational distribution, ecology (indexed by male calling height), and body size, and phylogenetically corrected regression was employed to examine the relationships between these three traits.ResultsWe obtained strong support for a monophyletic lineage comprising the majority of taxa sampled. Within this clade we identified one subclade that appears to have diversified primarily in montane habitats of the Central Cordillera (>1,000 m a.s.l.), with subsequent dispersal to isolated North Papuan Mountains. A second subclade (characterised by moderately to very elongated snouts) appears to have diversified primarily in hill forests (<1,000 m a.s.l.), with inferred independent upwards colonisations of isolated montane habitats, especially in isolated North Papuan Mountains. We found no clear relationship between extremely small body size (adult SVL less than 15 mm) and elevation, but a stronger relationship with ecology—smaller species tend to be more terrestrial.ConclusionsOrogeny and climatic oscillations have interacted to generate high montane biodiversity in New Guinea via both localised diversification within montane habitats (centric endemism) and periodic dispersal across lowland regions (eccentric endemism). The correlation between extreme miniaturisation and terrestrial habits reflects a general trend in frogs, suggesting that ecological or physiological constraints limit niche usage by miniaturised frogs, even in extremely wet environments such as tropical mountains.

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