scholarly journals Songs in the understory and colors in the canopy: habitat structure leads to different avian communication strategies in a tropical montane forest

2018 ◽  
Author(s):  
Oscar Laverde-R ◽  
Carlos Daniel Cadena
Keyword(s):  
Communication Strategies ◽  
Negative Relationship ◽  
Montane Forest ◽  
Tropical Montane Forest ◽  
Sensory Drive ◽  
Communication Signals ◽  
Forest Bird ◽  
Different Types ◽  
Bird Assemblage ◽  
Signaling Strategies

AbstractBirds inhabit a variety of habitats and they communicate using primarily visual and acoustic signals; two central hypotheses have been postulated to study the evolution of such a signals. The sensory drive hypothesis posits that variation in the physical properties of habitats leads to variation in natural selection pressures by affecting the ease with which different types of signals are perceived. Assuming that resources are limited for animals, the transfer hypothesis predicts a negative relationship between the investments in different types of signals. We evaluated these two hypotheses in a tropical montane forest bird assemblage. We also postulate a possible interaction between these two hypotheses: we predicted that the negative relationships between signals should be observed only when jointly considering birds from different environments (e.g. understory and canopy) due to the expected differences in communication strategies between habitats. The sensory drive hypothesis was supported by the differences we found between strata in vocal output, patch contrast to background and color conspicuousness, but not for the variables associated to song elaboration and hue disparity. We found support for the transfer hypothesis: birds with colors contrasting less against the background sing more frequently and birds with lower diversity of colors produce longer songs, understory birds showed also a negative relationship between signals, but only when accounting for phylogeny. We found partial support for the interaction between the sensory drive and the transfer hypotheses: hue disparity and vocal output were negatively related only when analyzing together birds from the canopy and the understory, but not when analyzing them separately. We conclude that the study of the evolution of communication signals needs to consider more than one channel and the functional interactions between them. The results of the interaction of optimal signaling strategies in two communication channels in the local habitats where animals signaling, are the patterns of colors and songs we revealed in a tropical montane forest bird assemblage.

scholarly journals Evolution of bird communication signals: transference between signals mediated by sensory drive

2017 ◽  
Author(s):  
Oscar Laverde-R. ◽  
Michael J. Ryan ◽  
Carlos Daniel Cadena
Keyword(s):  
Vegetation Structure ◽  
Habitat Type ◽  
Negative Relationship ◽  
Visual Signals ◽  
High Rate ◽  
Costs And Benefits ◽  
Sensory Drive ◽  
Communication Signals ◽  
Song Variation ◽  
Sensory Modalities

Animals communicate using signals perceived via multiple sensory modalities but usually invest more heavily in one of type of signal. This pattern, observed by Darwin1 and many researchers since, led to development of the transfer hypothesis (see also transferal effect2 and tradeoff hypothesis3,4), which predicts a negative relationship between investment in different signaling modalities dictated by the relative costs and benefits of each. One factor that influences costs and benefits, and is central to the sensory drive hypothesis5 posed to account for signal evolution, is the suitability of the environment for different types of signals. Movement into a dark habitat, for example, should favor investment in acoustic over visual signals. We use phylogenetic comparative methods to analyze the joint effect of transfer and sensory drive on plumage and song variation in 52 species of a large radiation of passerine birds, the New World warblers (Parulidae), and to estimate temporal patterns in the accumulation of differences in visual and vocal signals and habitat along the evolutionary history of this lineage. We found evidence for the predicted negative correlations between a variety of song and plumage traits that vary with habitat type. Plumage contrast to background and chromatic diversity were both negatively related to syllable variety when vegetation structure was a covariate: birds with a greater variety of song syllables and less colorful plumages live in closed or darker habitats. Also as predicted, achromatic or brightness diversity was related to vegetation structure. In addition, disparity-through-time analyses showed that when one set of traits (i.e. songs or colors) diversified at a relatively high rate the other did not, as predicted by the transfer hypothesis. Our results show that sensory drive influences the transfer of investment between traits in different sensory modalities. This interaction between mechanisms shaping signals may be a major determinant in the evolution of animal communication.

Simulating forest dynamics of a tropical montane forest in South Ecuador

Erdkunde ◽  
2009 ◽  
Vol 63 (4) ◽  
pp. 347-364 ◽  
Author(s):  
Claudia Dislich ◽  
Sven Günter ◽  
Jürgen Homeier ◽  
Boris Schröder ◽  
Andreas Huth
Keyword(s):  
Forest Dynamics ◽  
Montane Forest ◽  
Tropical Montane Forest

Ammonium, nitrate and glycine uptake of six Ecuadorian tropical montane forest tree species: anin situpot experiment with saplings

2014 ◽  
Vol 31 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Bärbel Wittich ◽  
Jürgen Homeier ◽  
Christoph Leuschner
Keyword(s):  
Tree Species ◽  
N Uptake ◽  
Tropical Trees ◽  
Forest Tree ◽  
Montane Forest ◽  
Tropical Montane Forest ◽  
Organic N ◽  
Coarse Roots ◽  
N Form ◽  
Form Preference

Abstract:Not much is known about the nitrogen (N) uptake capacity and N-form preference of tropical trees. In a replicated labelling experiment with15N-ammonium,15N-nitrate and dual-labelled glycine applied to saplings of six tree species from southern Ecuadorian montane forests, we tested the hypotheses that (1) the saplings of tropical trees are capable of using organic N even though they are forming arbuscular mycorrhizas, and (2) with increasing altitude, tree saplings increasingly prefer ammonium and glycine over nitrate due to reduced nitrification and growing humus accumulation. Three- to 5-y-old saplings of two species each from 1000, 2000 and 3000 m asl were grown in pots inside the forest at their origin and labelled with non-fertilizing amounts of the three N forms;15N enrichment was detected 5 days after labelling in fine roots, coarse roots, shoots and leaves. The six species differed with respect to their N-form preference, but neither the abundance of ammonium and nitrate in the soil nor altitude (1000–3000 m asl) seemed to influence the preference. Two species (those with highest growth rate) preferred NH4+over NO3−, while the other four species took up NO3−and NH4+at similar rates when both N forms were equally available. After13C-glycine addition,13C was significantly accumulated in the biomass of three species (all species with exclusively AM symbionts) but a convincing proof of the uptake of intact glycine molecules by these tropical montane forest trees was not obtained.

Vertical patterns and duration of surface wetness in an old-growth tropical montane forest, Indonesia

Flora ◽  
2007 ◽  
Vol 202 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Johannes Dietz ◽  
Christoph Leuschner ◽  
Dirk Hölscher ◽  
Heinrich Kreilein
Keyword(s):  
Montane Forest ◽  
Tropical Montane Forest ◽  
Old Growth ◽  
Surface Wetness

Variation in longevity and traits of leaves among co-occurring understorey plants in a tropical montane forest

2008 ◽  
Vol 24 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Satomi Shiodera ◽  
Joeni S. Rahajoe ◽  
Takashi Kohyama
Keyword(s):  
Life Form ◽  
Census Data ◽  
Condensed Tannin ◽  
Leaf Traits ◽  
Life Forms ◽  
Montane Forest ◽  
Cox Proportional Hazards ◽  
Leaf Longevity ◽  
Tropical Montane Forest ◽  
Leaf Mass Per Area

Abstract:The relationship between leaf longevity and other leaf traits was compared among different life-form categories (trees, herbs, climbers and epiphytes) of 101 plant species in a tropical montane forest on Mt. Halimun, West Java, Indonesia. We applied the Cox proportional hazards regression to estimate the leaf longevity of each species from 30 mo of census data. We examined whether estimated longevity was explained by either species life-form categories, taxonomic groupings (eudicots, monocots, magnoliids and chloranthales, and ferns) or such leaf traits as leaf area, leaf mass per area (LMA), mass-based leaf nitrogen, penetrometer reading, condensed-tannin-free total phenolics and condensed tannin. There was a wide-ranged interspecific variation in leaf longevity, mostly 10–50 mo, similarly across life-form categories. LMA showed a strong positive influence on leaf longevity. We found that relationships between leaf longevity and some leaf traits were different among various life forms. Trees tended to have high LMA, while climbers tended to have low LMA at the same leaf longevity. We hypothesize that such difference among life forms reflects shoot architecture characteristics. Multi-shoot trees with branching architecture need to have self-supporting leaves, whereas semi-epiphytic climbers can maintain relatively low biomass investment to leaves hanging or relying upon the mechanical support from host plants.

scholarly journals Investigating the Extent to Which Personality Traits and Demographics Affect Job Satisfaction

2016 ◽  
Vol 4 (1) ◽  
pp. 70 ◽  
Author(s):  
Muhammad Sajid Saeed
Keyword(s):  
Job Satisfaction ◽  
Personality Traits ◽  
Negative Relationship ◽  
Demographic Variables ◽  
The Other ◽  
Retail Sector ◽  
Primary Concern ◽  
Different Types ◽  
The Uk ◽  
Ranking Analysis

The primary concern of this paper is to investigatethe extent to which three variables (i.e. personality traits, demographic variables, and job satisfaction) are interrelated with each other and what effect they have on each other in relation to the UK retail sector. The four different types of retail stores i.e. Tesco, Primark, Ikea and WH Smith were selected for survey purpose to minimise the class biasness.Total 300 close-ended questionnaires were distributed and 220 responses were obtained.The findings reveal that ‘Neuroticism’ is negatively associated with job satisfaction as well as with ‘Extraversion’. However, it is positively correlated with other three personality groups including ‘Agreeableness’, ‘Conscientious’, and ‘Openness’. On the other hand, ‘Openness to experience’ has a negative relationship with ‘Agreeableness’.It is also found from the ranking analysis that employees with ‘Agreeableness’ and ‘Conscientiousness’ personalities are more successful in their career and consequently they are more satisfied with their jobs.

scholarly journals Family Functioning, Emotional Intelligence and Values: Analysis of the Relationship with Aggressive Behavior in Adolescents

2018 ◽  
Author(s):  
María del Carmen Pérez-Fuentes ◽  
María del Mar Molero ◽  
Ana Belén Barragán ◽  
José Jesús Gázquez Linares
Keyword(s):  
Emotional Intelligence ◽  
High School Students ◽  
Family Functioning ◽  
Aggressive Behavior ◽  
Adolescent Development ◽  
Negative Relationship ◽  
School Students ◽  
Different Types ◽  
Emotional Intelligence Inventory ◽  
The Relationship

Aggressive behavior in adolescence is influenced by a diversity of individual, family and social variables. The purpose of this study was to analyze the relationship between family functioning, emotional intelligence and values for development of different types of aggression, as well as to establish profiles according to the predictor variables of aggression. To do this, a sample of 317 high school students aged 13 to 18 were administered the Peer Conflict Scale, the Family Functionality Scale, the Brief Emotional Intelligence Inventory for Senior Citizens and the Values for Adolescent Development Scales. The study showed that stress management, positive adolescent development and family functioning predominated in nonaggressive subjects with higher scores than aggressors. There was also a negative relationship between the different types of aggression and emotional intelligence, positive values and family functioning. In addition, two different profiles were found. The first had low scores on all the variables, while the second profile had higher scores on all the variables except family functioning which was higher.

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