The formation of supraglacial debris covers by primary dispersal from transverse englacial debris bands

2013 ◽  
Vol 38 (15) ◽  
pp. 1779-1792 ◽  
Author(s):  
Martin P. Kirkbride ◽  
Philip Deline
Keyword(s):  
Primary Dispersal

scholarly journals THE EFFECT OF THE LIPID AND FATTY ACID STATUS OF ATLANTIC SALMON, SALMO SALAR L., FINGERLINGS ON THEIR PRIMARY DISPERSAL AND FORMATION OF PHENOTYPIC GROUPS

2016 ◽  
pp. 99 ◽  
Author(s):  
Зинаида Анатольевна Нефедова ◽  
Светлана Александровна Мурзина ◽  
Светлана Николаевна Пеккоева ◽  
Алексей Елпидифорович Веселов ◽  
Нина Николаевна Немова ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Fatty Acid Status ◽  
Atlantic Salmon Salmo Salar ◽  
Acid Status ◽  
Phenotypic Groups ◽  
Primary Dispersal

Spatial patterns of primary seed dispersal and adult tree distributions: Genipa americana dispersed by Cebus capucinus

2015 ◽  
Vol 31 (6) ◽  
pp. 491-498 ◽  
Author(s):  
Kim Valenta ◽  
Mariah E. Hopkins ◽  
Melanie Meeking ◽  
Colin A. Chapman ◽  
Linda M. Fedigan
Keyword(s):  
Seed Dispersal ◽  
Spatial Patterns ◽  
Cebus Capucinus ◽  
Spatial Distributions ◽  
Dispersal Patterns ◽  
Seed Shadow ◽  
Adult Trees ◽  
Adult Tree ◽  
Tree Distributions ◽  
Primary Dispersal

Abstract:The spatial distribution of adult trees is typically not expected to reflect the spatial patterns of primary seed dispersal, due to many factors influencing post-dispersal modification of the seed shadow, such as seed predation, secondary seed dispersal and density-dependent survival. Here, we test the hypothesis that spatial distributions of primary seed shadows and adult trees are concordant by analysing the spatial distributions of adult Genipa americana trees and the seed shadow produced by its key primary disperser, the capuchin monkey (Cebus capucinus) in a tropical dry forest in Costa Rica. We mapped the dispersal of G. americana seeds by the capuchins during focal animal follows (mean = 463 min, n = 50) of all adults in one free-ranging group over two early wet seasons (May–July, 2005 and 2006). We mapped the locations of all G. americana trees within a 60-ha plot that lay within the home range of the capuchin group. We conducted multiple spatial point pattern analyses comparing degrees of clustering of capuchin defecations and G. americana trees. We found that adult tree distributions and primary dispersal patterns are similarly aggregated at multiple spatial scales, despite the modification of the primary dispersal patterns and long dispersal distances.

Soil seed bank composition over desert microhabitats: patterns and plausible mechanisms

2004 ◽  
Vol 82 (12) ◽  
pp. 1809-1816 ◽  
Author(s):  
Luis Marone ◽  
Víctor R Cueto ◽  
Fernando A Milesi ◽  
Javier Lopez de Casenave
Keyword(s):  
Seed Production ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Bare Soil ◽  
Seed Density ◽  
Seed Composition ◽  
Monte Desert ◽  
Total Seed ◽  
Seed Dynamics ◽  
Primary Dispersal

We assessed soil seed bank composition and size over several microhabitats of two habitats of the central Monte Desert of Argentina (open Prosopis woodland and Larrea shrubland) to analyse differences among them. Seed densities were similar to those already reported for other deserts, but we found consistent differences in seed composition among microhabitats. Whereas grass seeds (e.g., Aristida, Pappophorum, Neobouteloua, Trichloris, Digitaria) prevailed in natural depressions of open areas, forb seeds (e.g., Phacelia, Lappula, Descurainia, Plantago, Chenopodium) were more abundant under trees. The comparison of seed production during primary dispersal (i.e., seed rain) with seed density on the ground at the end of dispersal indicated that most forb seeds entered the habitat through the micro habitats located beneath the canopy of trees and tall shrubs, and remained there after redistribution. Most grass seeds, by contrast, entered it through bare-soil and under-grass microhabitats, and reached more even distributions after secondary dispersal, especially because of dramatic losses in bare soil. Patterns of plant recruitment and seed dynamics in specific microhabitats were better understood when differences of soil seed bank composition, but not of total seed density, were taken into account.Key words: Monte Desert, seed dispersal, seed predation, seed production, seeds.

scholarly journals Wing loading, not terminal velocity, is the best parameter to predict capacity of diaspores for secondary wind dispersal

2020 ◽  
Vol 71 (14) ◽  
pp. 4298-4307 ◽  
Author(s):  
Wei Liang ◽  
Zhimin Liu ◽  
Minghu Liu ◽  
Xuanping Qin ◽  
Carol C Baskin ◽  
...  
Keyword(s):  
Shape Index ◽  
Terminal Velocity ◽  
Wind Dispersal ◽  
Wing Loading ◽  
Dispersal Capacity ◽  
Secondary Dispersal ◽  
Lift Off ◽  
Best Parameter ◽  
The Relationship ◽  
Primary Dispersal

Abstract Lift-off velocity may be the most useful surrogate to measure the secondary dispersal capacity of diaspores. However, the most important diaspore attribute determining diaspore lift-off velocity is unclear. Furthermore, it is not known whether terminal velocity used to characterize the primary dispersal capacity of diaspores can also be used to predict their secondary wind dispersal capacity. Here, we investigate how diaspore attributes are related to lift-off velocity. Thirty-six species with diaspores differing in mass, shape index, projected area, wing loading, and terminal velocity were used in a wind tunnel to determine the relationship between diaspore attributes and lift-off velocity. We found that diaspore attributes largely explained the variation in lift-off velocity, and wing loading, not terminal velocity, was the best parameter for predicting lift-off velocity of diaspores during secondary wind dispersal. The relative importance of diaspore attributes in determining lift-off velocity was modified by both upwind and downwind slope directions and type of diaspore appendage. These findings allow us to predict diaspore dispersal behaviors using readily available diaspore functional attributes, and they indicate that wing loading is the best proxy for estimating the capacity for secondary dispersal by wind.

scholarly journals The role of herbivorous insects and pathogens in the regeneration dynamics of Guazuma ulmifolia in Panama

2019 ◽  
Vol 32 ◽  
pp. 81-101 ◽  
Author(s):  
Raphaële Solé ◽  
Sofia Gripenberg ◽  
Owen T. Lewis ◽  
Lars Markesteijn ◽  
Héctor Barrios ◽  
...  
Keyword(s):  
Tree Species ◽  
Significant Proportion ◽  
Herbivorous Insects ◽  
Strong Positive Correlation ◽  
Seedling Mortality ◽  
Regeneration Dynamics ◽  
Guazuma Ulmifolia ◽  
Early Regeneration ◽  
Primary Dispersal

A significant proportion of the mortality of rainforest trees occurs during early life stages (seeds and seedlings), but mortality agents are often elusive. Our study investigated the role of herbivorous insects and pathogens in the early regeneration dynamics of Guazumaulmifolia (Malvaceae), an important tree species in agroforestry in Central America. We reared pre-dispersal insect seed predators from G.ulmifolia seeds in Panama. We also carried out an experiment, controlling insects and pathogens using insecticide and/or fungicide treatments, as well as seed density, and compared survivorship of G.ulmifolia seeds and seedlings among treatments and relative to untreated control plots. We observed (1) high pre-dispersal attack (92%) of the fruits of G.ulmifolia, mostly by anobiine and bruchine beetles; (2) negligible post-dispersal attack of isolated seeds by insects and pathogens; (3) slow growth and high mortality (> 95%) of seedlings after 14 weeks; (4) low insect damage on seedlings; and (5) a strong positive correlation between seedling mortality and rainfall. We conclude that for G.ulmifolia at our study site the pre-dispersal seed stage is by far the most sensitive stage to insects and that their influence on seedling mortality appears to be slight as compared to that of inclement weather. Thus, the regeneration of this important tree species may depend on effective primary dispersal of seeds by vertebrates (before most of the seed crop is lost to insects), conditioned by suitable conditions in which the seedlings can grow.

scholarly journals The parakeet Brotogeris tirica feeds on and disperses the fruits of the palm Syagrus romanzoffiana in Southeastern Brazil

2008 ◽  
Vol 8 (1) ◽  
pp. 231-234 ◽  
Author(s):  
Ivan Sazima
Keyword(s):  
Atlantic Forest ◽  
Southeastern Brazil ◽  
Northern Coast ◽  
Mother Tree ◽  
Dispersal Agent ◽  
Dispersal Agents ◽  
Palm Fruits ◽  
Syagrus Romanzoffiana ◽  
Trees And Shrubs ◽  
Primary Dispersal

Small psittacids remain unrecorded as dispersal agents of palm fruits in Brazil. I record here the plain parakeet (Brotogeris tirica), an Atlantic forest endemic, feeding on and dispersing the fruits of the palm Syagrus romanzoffiana at Ubatuba, northern coast of São Paulo, Southeastern Brazil. The birds removed the fruit and carried it away from the mother-tree in about 40% of the feeding records. While perched on trees and shrubs of the understorey, the parakeets removed and ingested most of the mesocarp, dropping the partly consumed fruit. As the parakeets damaged no the embryo and may feed at a distance from the mother-tree, they act as primary dispersal agents. This is the first substantiated record of a small Neotropical psittacid as a stomatochorous dispersal agent of palm fruits the size of A. romanzoffiana drupes.

scholarly journals Seed ingestion and germination in rattlesnakes: overlooked agents of rescue and secondary dispersal

2018 ◽  
Vol 285 (1872) ◽  
pp. 20172755 ◽  
Author(s):  
Randall S. Reiserer ◽  
Gordon W. Schuett ◽  
Harry W. Greene
Keyword(s):  
Seed Dispersal ◽  
Population Ecology ◽  
Empirical Studies ◽  
Evolutionary Process ◽  
Terrestrial Plants ◽  
Frugivorous Birds ◽  
Secondary Dispersal ◽  
Cheek Pouches ◽  
Primary Dispersal

Seed dispersal is a key evolutionary process and a central theme in the population ecology of terrestrial plants. The primary producers of most land-based ecosystems are propagated by and maintained through various mechanisms of seed dispersal that involve both abiotic and biotic modes of transportation. By far the most common biotic seed transport mechanism is zoochory, whereby seeds, or fruits containing them, are dispersed through the activities of animals. Rodents are one group of mammals that commonly prey on seeds (granivores) and play a critical, often destructive, role in primary dispersal and the dynamics of plant communities. In North America, geomyid, heteromyid and some sciurid rodents have specialized cheek pouches for transporting seeds from plant source to larder, where they are often eliminated from the pool of plant propagules by consumption. These seed-laden rodents are commonly consumed by snakes as they forage, but unlike raptors, coyotes, bobcats, and other endothermic predators which eat rodents and are known or implicated to be secondary seed dispersers, the role of snakes in seed dispersal remains unexplored. Here, using museum-preserved specimens, we show that in nature three desert-dwelling rattlesnake species consumed heteromyids with seeds in their cheek pouches. By examining the entire gut we discovered, furthermore, that secondarily ingested seeds can germinate in rattlesnake colons. In terms of secondary dispersal, rattlesnakes are best described as diplochorous. Because seed rescue and secondary dispersal in snakes has yet to be investigated, and because numerous other snake species consume granivorous and frugivorous birds and mammals, our observations offer direction for further empirical studies of this unusual but potentially important channel for seed dispersal.

scholarly journals Additive effects of connectivity provided by different habitat types drive plant assembly

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Léa Uroy ◽  
Cendrine Mony ◽  
Aude Ernoult
Keyword(s):  
Empirical Studies ◽  
Agricultural Landscapes ◽  
Plant Responses ◽  
Herbaceous Plant ◽  
Habitat Types ◽  
Plant Assemblage ◽  
Dispersal Vectors ◽  
Random Expectation ◽  
Plant Assemblages ◽  
Primary Dispersal

Abstract How connectivity affects plant assemblages is a central issue in landscape ecology. So far, empirical studies have produced contradictory results, possibly because studies: (1) inaccurately assess connectivity by prioritizing the respective effect of the type of habitat on plant assemblages and (2) omit the range of possible plant responses to connectivity depending on dispersal vectors. We focused on three dominant habitat types in agricultural landscapes (woodland, grassland and cropland), and analysed the effect of connectivity on herbaceous plant assemblage similarity for three primary dispersal modes (animal-dispersed, wind-dispersed and unassisted). Using circuit theory, we measured connectivity provided by woodland, grassland and cropland habitats independently. The similarity of plant assemblages was evaluated relative to the random expectation based on the regional pool. Overall, plant assemblage similarity in woodlands and temporary grasslands was dependent on connectivity, but not in wheat croplands. Only animal-dispersed species responded to connectivity. The similarity of animal-dispersed assemblages in woodlands was increased by the connectivity provided by woodland habitats, but was reduced by cropland habitats, whereas in temporary grasslands, similarity was increased by the connectivity provided by cropland habitats. Our results suggest that animal-dispersed species supplement their dispersal pathways, thus improving our knowledge of plant assembly rules in fragmented landscapes.

Sign in / Sign up

Export Citation Format

Share Document