scholarly journals Do Coarser Gap Mosaics in Conifer Plantations Induce More Seed Dispersal by Birds? Temporal Changes during 12 Years after Gap Creation

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 918
Author(s):  
Tsubasa Takano ◽  
Yohsuke Kominami ◽  
Hiromi Mizunaga
Keyword(s):  
Seed Dispersal ◽  
Species Composition ◽  
Winter Season ◽  
Temporal Changes ◽  
Canopy Gaps ◽  
Vegetation Development ◽  
Frugivorous Birds ◽  
Α Diversity ◽  
Conifer Plantations ◽  
Gap Creation

The creation of canopy gaps is thought to be an efficient silvicultural operation to diversify species composition of monoculture conifer plantations; however, the shortage of regeneration materials in overclosed plantations is one of the concerns related to this operation. Seed dispersal by frugivorous birds may play an important role in inducing the spread of native broad-leaved trees in canopy gaps in plantations in the warm temperate zone of central Japan because bird-dispersed woody species are abundant in this area. We monitored the dynamics of the abundance and species composition of bird-dispersed seeds over 12 years after gap creation in the canopy of a Japanese cypress (Chamaecyparis obtusa (Siebold et Zucc.) Endl.) plantation. We also studied the effects of gap-mosaic patterns (from many small gaps to fewer large gaps) on dispersal. We used a hierarchical Bayesian zero-inflated Poisson model to analyze the factors affecting seed dispersal by frugivorous birds. Seed dispersal by birds increased with gap age except for just after gap creation. Dispersal in coarser gap mosaics was more abundant than that in finer gap mosaics. The species diversity of dispersed seeds in each seed trap (α-diversity) and plot (γ-diversity) showed similar trends in terms of temporal changes and differences between plots related to seed dispersal abundance; β-diversity did not. These trends might have been caused by shrub-vegetation development after gap creation. The effects of shrub vegetation were classified into the attraction by fruits borne within the vegetation, as well as other effects related to vegetation, such as functions of perch availability and insect presence as a food source. The presence of bird-dispersed seeds was strongly promoted by vegetation in all seasons, but only marginally by the presence of fruit-bearing vegetation. However, fruits attracted seed dispersal by frugivorous birds in the winter season. Our results suggest that both vegetation development and fruiting are important for promoting seed dispersal by frugivorous birds, and those effects are different in different seasons according to vegetation conditions and shifting food resources.

scholarly journals Faecal analysis of frugivorous birds and seed dispersal in conifer plantations

2009 ◽  
Vol 58 (2) ◽  
pp. 187-191 ◽  
Author(s):  
Ryoko Hirata ◽  
Kunihiko Hata ◽  
Koichi Sone
Keyword(s):  
Seed Dispersal ◽  
Frugivorous Birds ◽  
Faecal Analysis ◽  
Conifer Plantations

Fruits foraging patterns and seed dispersal effect of frugivorous birds on Hippophae rhamnoides sinensis

2006 ◽  
Vol 1 (3) ◽  
pp. 318-322 ◽  
Author(s):  
Xianwen Lu ◽  
Kun Sun ◽  
Ruijun Ma ◽  
Hui Zhang ◽  
Xue Su ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Hippophae Rhamnoides ◽  
Frugivorous Birds ◽  
Foraging Patterns ◽  
Hippophaë Rhamnoides

scholarly journals Opportunities for winter prescribed burning in mixed conifer plantations of the Sierra Nevada

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Robert A. York ◽  
Jacob Levine ◽  
Kane Russell ◽  
Joseph Restaino
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Prescribed Burning ◽  
Winter Season ◽  
Basal Area ◽  
Weather Conditions ◽  
Shrub Cover ◽  
Mixed Conifer ◽  
Planted Forests ◽  
Conifer Plantations

Abstract Background Young, planted forests are particularly vulnerable to wildfire. High severity effects in planted forests translate to the loss of previous reforestation investments and the loss of future ecosystem service gains. We conducted prescribed burns in three ~35-year-old mixed conifer plantations that had previously been masticated and thinned during February in order to demonstrate the effectiveness of winter burning, which is not common in the Sierra Nevada, California. Results On average, 59% of fine fuels were consumed and the fires reduced shrub cover by 94%. The average percent of crown volume that was damaged was 25%, with no mortality observed in overstory trees 1 year following the fires. A plot level analysis of the factors of fire effects did not find strong predictors of fuel consumption. Shrub cover was reduced dramatically, regardless of the specific structure that existed in plots. We found a positive relationship between crown damage and the two variables of Pinus ponderosa relative basal area and shrub cover. But these were not particularly strong predictors. An analysis of the weather conditions that have occurred at this site over the past 20 years indicated that there have consistently been opportunities to conduct winter burns. On average, 12 days per winter were feasible for burning using our criteria. Windows of time are short, typically 1 or 2 days, and may occur at any time during the winter season. Conclusions This study demonstrates that winter burning can be an important piece of broader strategies to reduce wildfire severity in the Sierra Nevada. Preparing forest structures so that they can be more feasible to burn and also preparing burn programs so that they can be nimble enough to burn opportunistically during short windows are key strategies. Both small landowners and large agencies may be able to explore winter burning opportunities to reduce wildfire severity.

Seed dispersal effectiveness by frugivorous birds: Identifying functional equivalent species in bird assemblages

2019 ◽  
Vol 12 (3) ◽  
pp. 103-108
Author(s):  
Facundo Xavier Palacio
Keyword(s):  
Seed Dispersal ◽  
Statistical Significance ◽  
Bird Species ◽  
Kernel Functions ◽  
Bird Conservation ◽  
Frugivorous Birds ◽  
Seed Dispersal Effectiveness ◽  
Bird Assemblages ◽  
Functional Equivalent ◽  
Dispersal Effectiveness

Seed dispersal by birds is a pivotal ecosystem function worldwide; yet, the rapid and ongoing global biodiversity loss poses a major threat to this essential ecosystem service. Seed dispersal effectiveness (SDE) is a key outcome of the interaction, represented by the product of seed dispersal quantity (number of seed dispersed) and quality (probability of recruitment of dispersed seeds). Therefore, identifying functional equivalent species in terms of SDE should become a key issue for bird conservation, since the effects of local extinctions on seed dispersal services may be weakened by remaining equivalent species. However, a method to quantitatively identify functional equivalent species in frugivorous bird assemblages is still lacking. To estimate SDE overlap between seed dispersers and assess whether two species may be functionally equivalent, I apply a novel nonparametric niche overlap index based on kernel functions and null models to test its statistical significance. For each bird species, I account for intraspecific variation in seed dispersal effectiveness to obtain a distribution of seed dispersal effectiveness values, an often neglected source of variation in seed dispersal assemblages. Non-significant differences in seed dispersal effectiveness overlap support the hypothesis that two species are functional equivalent, thus playing similar functional roles. The model proposed is applicable to any other quantity or quality component and is independent from the method or sampling design used to quantify SDE. The identification of functional equivalent species in seed dispersal assemblages adds to the theoretical framework of seed dispersal effectiveness and offers new insights into the ecology of the seed dispersal service provided by birds.

scholarly journals Seed Dispersal by Frugivores and Germination Success of the Invasive Alien Shrub Pyracantha Angustifolia in the Eastern Free State Province, South Africa

2021 ◽  
Author(s):  
Lehlohonolo Donald Adams ◽  
Grant D. Martin ◽  
Colleen T. Downs ◽  
Vincent Ralph Clark ◽  
Vuyisile Thabethe ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Bird Species ◽  
Camera Traps ◽  
Free State ◽  
Fruit Pulp ◽  
Frugivorous Birds ◽  
Alien Plant ◽  
Free State Province ◽  
Germination Success ◽  
Eastern Free State

Abstract Invasive alien plants can use animal-plant interactions to increase their invasiveness. This study investigated the role of frugivorous birds in seed dispersal and germination of the alien plant Pyracantha angustifolia (Rosaceae) in South African high elevation grasslands. We monitored which bird species fed on the fruit of the invasive P. angustifolia in some farms in the Eastern Free State Province using camera-traps and direct surveillance. Nine bird species visited P. angustifolia shrubs to perch or feed on fruits, but only one bird (Speckled Mousebird) fed on the fruits during timed observations. To assess the effect of ingestion by avian frugivores on P. angustifolia germination, P. angustifolia fruits were fed to captive Cape White-eyes (Zosterops virens), Dark-capped Bulbuls (Pycnonotus tricolor), Purple-crested Turacos (Gallirex porphyreolophus), Red-winged Starlings (Onychognathus morio) and Speckled Mousebirds (Colius striatus). Seeds collected from bird excreta, whole fruits, and depulped fruits were grown under greenhouse conditions and germination rates recorded. All captive bird species, except for Cape White-eyes, ingested the seeds; Cape White-eyes only fed on fruit pulp that they had manually removed. Bird species with relatively larger body mass had longer seed retention times compared with the smaller bird species. Germination success of both depulped and ingested P. angustifolia seeds was high (> 80%) and that of whole fruits low (7%). Ingestion by the four avian frugivore species did not affect germination rate and success; instead, the birds facilitate the spread and germination of seeds by removing the fruit pulp and spreading the seed away from the parent shrubs.

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