scholarly journals Variation in ant-mediated seed dispersal along elevation gradients

2018 ◽  
Author(s):  
Israel Del Toro ◽  
Relena R Ribbons
Keyword(s):  
Seed Dispersal ◽  
Elevation Gradient ◽  
High Elevation ◽  
Seed Removal ◽  
Species Identity ◽  
Insect Communities ◽  
Removal Rates ◽  
Elevation Gradients ◽  
Ant Community ◽  
Lower Elevation

Ant-mediated seed dispersal, also known as myrmecochory, is a widespread and important mutualism that structures both plant and insect communities. However the extent to which myrmecochory is driven by abiotic and biotic environmental factors remains unclear. We used a replicated standardized seed removal experiment along elevation gradients in four mountain ranges in the southwestern United States to test predictions that: (1) seed removal rates would be greater at lower elevations, and (2) seed species identity influences seed removal rates, (i.e. seeds from their native elevation range would be removed at higher rates than seeds outside of their range). Both predictions were supported. Seed removal rates were ~25% higher at lower elevation sites than at higher elevation sites. The low elevation Datura and high elevation Iris were removed at higher rates in their respective native ranges. We attribute observed differences in dispersal rates to changes in ant community composition, functional diversity, and abundance, suggesting that temperature variation along the elevation gradient.

scholarly journals Variation in ant-mediated seed dispersal along elevation gradients

2018 ◽  
Author(s):  
Israel Del Toro ◽  
Relena R Ribbons
Keyword(s):  
Seed Dispersal ◽  
Elevation Gradient ◽  
High Elevation ◽  
Seed Removal ◽  
Species Identity ◽  
Insect Communities ◽  
Removal Rates ◽  
Elevation Gradients ◽  
Ant Community ◽  
Lower Elevation

Ant-mediated seed dispersal, also known as myrmecochory, is a widespread and important mutualism that structures both plant and insect communities. However the extent to which myrmecochory is driven by abiotic and biotic environmental factors remains unclear. We used a replicated standardized seed removal experiment along elevation gradients in four mountain ranges in the southwestern United States to test predictions that: (1) seed removal rates would be greater at lower elevations, and (2) seed species identity influences seed removal rates, (i.e. seeds from their native elevation range would be removed at higher rates than seeds outside of their range). Both predictions were supported. Seed removal rates were ~25% higher at lower elevation sites than at higher elevation sites. The low elevation Datura and high elevation Iris were removed at higher rates in their respective native ranges. We attribute observed differences in dispersal rates to changes in ant community composition, functional diversity, and abundance, suggesting that temperature variation along the elevation gradient.

scholarly journals Variation in ant-mediated seed dispersal along elevation gradients

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6686 ◽  
Author(s):  
Israel Del Toro ◽  
Relena R. Ribbons
Keyword(s):  
Seed Dispersal ◽  
Environmental Gradients ◽  
Elevation Gradient ◽  
High Elevation ◽  
Seed Removal ◽  
Species Identity ◽  
Removal Rates ◽  
Ant Communities ◽  
Elevation Gradients ◽  
Elevation Range

Ant-mediated seed dispersal, also known as myrmecochory, is a widespread and important mutualism that structures both plant and ant communities. However, the extent to which ant functional types (e.g., granivorous generalists vs. myrmecochorous ants) across environmental gradients affect seed removal rates is not fully understood. We used a replicated, standardized seed removal experiment along elevation gradients in four mountain ranges in the southwestern United States to test predictions that: (1) seed removal rates would be greater at lower elevations, and (2) seed species identity influences seed removal rates (i.e., seeds from their native elevation range would be removed at higher rates than seeds outside of their native elevation range). Both predictions were supported. Seed removal rates were ∼25% higher at lower elevation sites than at higher elevation sites. The low elevation Datura and high elevation Iris were removed at higher rates in their respective native ranges. We attribute observed differences in dispersal rates to changes in ant community composition, functional diversity, and abundance. We also suggest that temperature variation along the elevation gradient may explain these differences in seed removal rates.

scholarly journals Elevation Gradient Altered Soil C, N, and P Stoichiometry of Pinus taiwanensis Forest on Daiyun Mountain

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1089
Author(s):  
Lan Jiang ◽  
Zhongsheng He ◽  
Jinfu Liu ◽  
Cong Xing ◽  
Xinguang Gu ◽  
...  
Keyword(s):  
Elevation Gradient ◽  
C:N Ratio ◽  
Phosphate Fertilizer ◽  
High Elevation ◽  
Driving Factors ◽  
Slope Position ◽  
Elevation Gradients ◽  
Soil C ◽  
Soil P ◽  
C And N

Researches focused on soil carbon (C), nitrogen (N), and phosphorus (P) content and the stoichiometry characteristics along elevation gradients are important for effective management of forest ecosystems. Taking the soil of different elevations from 900 to 1700 m on Daiyun Mountain as the object, the elevation distribution of total C, N, and P in soil and their stoichiometry characteristics were studied. Also, the driving factors resulting in the spatial heterogeneity of soil stoichiometry are presented. The results show the following: (1) The average soil C and N content was 53.03 g·kg−1 and 3.82 g·kg−1, respectively. The content of C and N at high elevation was higher than that of at low elevation. Soil phosphorus fluctuated with elevation. (2) With increasing elevation, soil C:N ratio increased initially to 17.40 at elevation between 900–1000 m, and then decreased to 12.02 at elevation 1600 m. The changing trends of C:P and N:P were similar, and they all fluctuated with elevation. (3) Elevation, soil bulk density, and soil temperature were the main factors influencing the variation of soil C, N, and C:N. Soil pH and slope position were the driving factors for soil P, C:P, and N:P. The soil is rich in C and N, and has less total phosphorus on Daiyun Mountain. Raising the level of phosphate fertilizer appropriately can help to improve soil fertility and promote plant growth as well. In light of this information, in the near future, it will be necessary to conduct separation management of C, N, and P with regular monitoring systems to maintain favorable conditions for soil.

scholarly journals Floristic Composition and Structure in Relation to Elevation in the Togo Plateau Forest Reserve in Ghana

2020 ◽  
Vol 1 (6) ◽  
Author(s):  
Gilchrist K. Faith Dogor ◽  
Emmanuel Acquah ◽  
Alexander K. Anning
Keyword(s):  
Elevation Gradient ◽  
Basal Area ◽  
Floristic Composition ◽  
Species Identity ◽  
R Software ◽  
Elevation Gradients ◽  
Forest Reserve ◽  
Composition And Structure ◽  
Special Scientific ◽  
Geographical Locations

Plateau ecosystems are of special scientific and conservation interests as they harbour rich plant diversity and exhibit considerable spatial variability along elevation gradients. In this study, variations in floristic composition and structure in relation to elevation were studied in six-fringed communities Hohoe (HH), Alavanyo (AL), Santrokofi (SA), Akpafu (AK), Bowuri (BO), and Nkonya (NK) of the Togo Plateau Forest Reserve in Ghana to better provide explicit and effective management of this ecological hotspot. A total of 180 plots (each measuring 25m × 25m) were demarcated across the six communities for sampling of trees (DBH measured at 1.3 m above ground ≥10 cm). Smaller nested plots, measuring 5m × 5m and 1m × 1m were used for sampling saplings (DBH < 10 cm, height > 1.5 m) and seedlings (DBH < 3 cm, height < 1.5 m), respectively. Species identity and abundance and elevation were recorded for each plot. Relationships of elevation gradients with vegetation attributes were analysed using simple linear regression and R software package. A total of 281 plant species (164 trees, 60 saplings and 57 seedlings) belonging to 66 families were recorded in the study. Leguminosae, Apocynaceae and Euphorbiaceae were the most dominant families across and along the elevation gradient. The average basal area of trees was calculated as 44.72 m2/ha and varied across the six communities (ranged from 57.10 m2/ha at BO to 33.10 m2/ha at AL) whereas the Shannon-Weiner Index (H’) averaged as 3.99 and varied across the six communities (ranged from4.14 m2/ha at BO to 3.89m2/ha at AL) and evenness index averaged as 0.96 (ranged from1.00at BO to 0.92 at AL). The saplings and seedlings also follow a similar pattern of composition and structure. The geographical locations of the study communities which somehow correspond with different elevations to the plateau (i.e., BO, NK occur in lower elevations, SA, AL in mid elevations and HH, AL in higher elevations) has been identified as the drivers of the composition and structure across the communities on the landscape. The most important trees listed in the study were C. pentandra, A. zygia, and T. superba. The saplings were A. camerunensis, M. puberula and C. ferruginea. The seedlings were C. odorata, P. hirsuta and C. affer. The most important tree species listed were distributed along a broad range of elevation. Results obtained revealed high biodiversity of the plateau. These findings may lead to a better understanding of the composition and structure of several plateau ecosystems found in Ghana and elsewhere.

scholarly journals Temporal and Spatial Characteristics of Precipitation and Temperature in Punjab, Pakistan

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1916 ◽  
Author(s):  
Nawaz ◽  
Li ◽  
Chen ◽  
Guo ◽  
Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Climatic Variability ◽  
Regional Scale ◽  
Elevation Gradient ◽  
High Elevation ◽  
Maximum Temperature ◽  
Moderate Increase ◽  
Study Region ◽  
Lower Elevation ◽  
Precipitation And Temperature

Identifying the changes in precipitation and temperature at a regional scale is of great importance for the quantification of climate change. This research investigates the changes in precipitation and surface air temperature indices in the seven irrigation zones of Punjab Province during the last 50 years; this province is a very important region in Pakistan in terms of agriculture and irrigated farming. The reliability of the data was examined using double mass curve and autocorrelation analysis. The magnitude and significance of the precipitation and temperature were visualized by various statistical methods. The stations’ trends were spatially distributed to better understand climatic variability across the elevation gradient of the study region. The results showed a significant warming trend in annual Tmin (minimum temperature) and Tmean (mean temperature) in different irrigation zones. However, Tmax (maximum temperature) had insignificant variations except in the high elevation Thal zone. Moreover, the rate of Tmin increased faster than that of Tmax, resulting in a reduction in the diurnal temperature range (DTR). On a seasonal scale, warming was more pronounced during spring, followed by that in winter and autumn. However, the summer season exhibited insignificant negative trends in most of the zones and gauges, except in the higher-altitude Thal zone. Overall, Bahawalpur and Faisalabad are the zones most vulnerable to warming annually and in the spring, respectively. Furthermore, the elevation-dependent trend (EDT) indicated larger increments in Tmax for higher-elevation (above 500 m a.s.l.) stations, compared to the lower-elevation ones, on both annual and seasonal scales. In contrast, the Tmin showed opposite trends at higher- and lower-elevation stations, while a moderate increase was witnessed in Tmean trends from lower to higher altitude over the study region. An increasing trend in DTR was observed at higher elevation, while a decreasing trend was noticed at the lower-elevation stations. The analysis of precipitation data indicated wide variability over the entire region during the study period. Most previous studies reported no change or a decreasing trend in precipitation in this region. Conversely, our findings indicated the cumulative increase in annual and autumn precipitation amounts at zonal and regional level. However, EDT analysis identified the decrease in precipitation amounts at higher elevation (above 1000 m a.s.l.) and increase at the lower-elevation stations. Overall, our findings revealed unprecedented evidence of regional climate change from the perspectives of seasonal warming and variations in precipitation and temperature extremes (Tmax and Tmin) particularly at higher-elevation sites, resulting in a variability of the DTR, which could have a significant influence on water resources and on the phenology of vegetation and crops at zonal and station level in Punjab.

scholarly journals Patterns of floral allocation along an elevation gradient: variation in Senecio subalpinus growing in the Tatra Mountains

Alpine Botany ◽  
2021 ◽  
Vol 131 (1) ◽  
pp. 117-124
Author(s):  
Piotr Kiełtyk
Keyword(s):  
Elevation Gradient ◽  
High Elevation ◽  
Tatra Mountains ◽  
Ecological Gradient ◽  
Elevation Gradients ◽  
Allocation Patterns ◽  
Abiotic And Biotic Factors ◽  
Elevational Shift ◽  
The Tatra Mountains ◽  
Gradient Variation

AbstractThis study examined the morphological variation in Senecio subalpinus W.D.J. Koch. (Asteraceae) along a 950-m elevation gradient in the Tatra Mountains, Central Europe, with emphasis on floral allocation patterns. Fifteen morphological traits were measured in 200 plants collected in the field from 20 sites then the findings were modelled by elevation using linear mixed-effects models. Plant aboveground biomass and height decreased steadily with increasing elevation; however, the most distinctive feature was the elevational shift in floral allocation patterns. Low-elevation plants had greater numbers of smaller flower heads with a lower overall number of flowers, while high-elevation plants had smaller numbers of bigger flower heads and a greater overall number of flowers. Accordingly, the mean individual flower mass increased significantly with increasing elevation. Interestingly, the width of the outer ligulate flowers also increased considerably with increasing elevation, increasing the fill of the overall circumference of the flower head. Results of this study confirmed that elevation is an important ecological gradient driving variation in vegetative and floral traits of S. subalpinus. Possible causes of the observed variations are subsequently discussed, including the varying effects of both abiotic and biotic factors with elevation gradients.

Embryo growth in Alaskan white spruce seeds

1988 ◽  
Vol 18 (1) ◽  
pp. 64-67 ◽  
Author(s):  
John C. Zasada
Keyword(s):  
Soil Moisture ◽  
Seed Dispersal ◽  
Embryo Development ◽  
Growing Season ◽  
White Spruce ◽  
High Elevation ◽  
Seed Collection ◽  
Interior Alaska ◽  
Lower Elevation ◽  
Soil Temperatures

Embryo development in white spruce seeds was studied in five stands in interior Alaska. Cones and seeds were collected at 10- to 14-day intervals starting in mid-July and continuing until just before seed dispersal began. Significant differences were found in embryo development between stands, between trees within stands, and between cones within trees. The four stands at lower elevations produced seeds that had embryos filling 95% or more of the embryo cavity; this percentage was significantly higher than the highest elevation stand where embryos filled about 75% of the embryo cavity at the end of the growing season. Relative cotyledon length was generally greater than 25% in the lower elevation stands and slightly less than 20% in the high elevation stand. Although seed collection can be started when embryos fill 75% of the embryo cavity, the results of this and other studies suggest that collecting seeds when embryos are more mature will result in better quality seeds. Air and soil temperatures and soil moisture levels associated with embryo development are presented.

scholarly journals Turnover of Lecanoroid Mycobionts and Their Trebouxia Photobionts Along an Elevation Gradient in Bolivia Highlights the Role of Environment in Structuring the Lichen Symbiosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Ian D. Medeiros ◽  
Edyta Mazur ◽  
Jolanta Miadlikowska ◽  
Adam Flakus ◽  
Pamela Rodriguez-Flakus ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Species Turnover ◽  
Elevation Gradient ◽  
Single Species ◽  
High Elevation ◽  
Regional Patterns ◽  
Elevation Gradients ◽  
Clade C ◽  
Community Shifts ◽  
Molecular Dataset

Shifts in climate along elevation gradients structure mycobiont–photobiont associations in lichens. We obtained mycobiont (lecanoroid Lecanoraceae) and photobiont (Trebouxia alga) DNA sequences from 89 lichen thalli collected in Bolivia from a ca. 4,700 m elevation gradient encompassing diverse natural communities and environmental conditions. The molecular dataset included six mycobiont loci (ITS, nrLSU, mtSSU, RPB1, RPB2, and MCM7) and two photobiont loci (ITS, rbcL); we designed new primers to amplify Lecanoraceae RPB1 and RPB2 with a nested PCR approach. Mycobionts belonged to Lecanora s.lat., Bryonora, Myriolecis, Protoparmeliopsis, the “Lecanora” polytropa group, and the “L.” saligna group. All of these clades except for Lecanora s.lat. occurred only at high elevation. No single species of Lecanoraceae was present along the entire elevation gradient, and individual clades were restricted to a subset of the gradient. Most Lecanoraceae samples represent species which have not previously been sequenced. Trebouxia clade C, which has not previously been recorded in association with species of Lecanoraceae, predominates at low- to mid-elevation sites. Photobionts from Trebouxia clade I occur at the upper extent of mid-elevation forest and at some open, high-elevation sites, while Trebouxia clades A and S dominate open habitats at high elevation. We did not find Trebouxia clade D. Several putative new species were found in Trebouxia clades A, C, and I. These included one putative species in clade A associated with Myriolecis species growing on limestone at high elevation and a novel lineage sister to the rest of clade C associated with Lecanora on bark in low-elevation grassland. Three different kinds of photobiont switching were observed, with certain mycobiont species associating with Trebouxia from different major clades, species within a major clade, or haplotypes within a species. Lecanoraceae mycobionts and Trebouxia photobionts exhibit species turnover along the elevation gradient, but with each partner having a different elevation threshold at which the community shifts completely. A phylogenetically defined sampling of a single diverse family of lichen-forming fungi may be sufficient to document regional patterns of Trebouxia diversity and distribution.

scholarly journals Differential phenotypic and genetic expression of defence compounds in a plant–herbivore interaction along elevation

2016 ◽  
Vol 3 (9) ◽  
pp. 160226 ◽  
Author(s):  
Ana L. Salgado ◽  
Tomasz Suchan ◽  
Loïc Pellissier ◽  
Sergio Rasmann ◽  
Anne-Lyse Ducrest ◽  
...  
Keyword(s):  
Gene Expression ◽  
Host Plant ◽  
De Novo ◽  
Alternative Hypothesis ◽  
Elevation Gradient ◽  
High Elevation ◽  
Elevation Gradients ◽  
Tissue Replacement ◽  
Plant Herbivore ◽  
Optimal Defence

Elevation gradients impose large differences in abiotic and biotic conditions over short distances, in turn, likely driving differences in gene expression more than would genetic variation per se , as natural selection and drift are less likely to fix alleles at such a narrow spatial scale. As elevation increases, the pressure exerted on plants by herbivores and on arthropod herbivores by predators decreases, and organisms spanning the elevation gradient are thus expected to show lower levels of defence at high elevation. The alternative hypothesis, based on the optimal defence theory, is that defence allocation should be higher in low-resource habitats such as those at high elevation, due to higher costs associated with tissue replacement. In this study, we analyse variation with elevation in (i) defence compound content in the plant Lotus corniculatus and (ii) gene expression associated with defence against predators in the specific phytophagous moth, Zygaena filipendulae . Both species produce cyanogenic glycosides (CNglcs) such as lotaustralin and linamarin as defence mechanisms, with the moth, in addition, being able to sequester CNglcs from its host plant. Specifically, we tested the assumption that the defence-associated phenotype in plants and the gene expression in the insect herbivore should covary between low- and high-elevation environments. We found that L. corniculatus accumulated more CNglcs at high elevation, a result in agreement with the optimal defence theory. By contrast, we found that the levels of expression in the defence genes of Z. filipendulae larvae were not related to the CNglc content of their host plant. Overall, expression levels were not correlated with elevation either, with the exception of the UGT33A1 gene, which showed a marginally significant trend towards higher expression at high elevation when using a simple statistical framework. These results suggest that the defence phenotype of plants against herbivores, and subsequent herbivore sequestration machineries and de novo production, are based on a complex network of interactions.

scholarly journals Climate Sensitivity of Tropical Trees Along an Elevation Gradient in Rwanda

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 647 ◽  
Author(s):  
Myriam Mujawamariya ◽  
Aloysie Manishimwe ◽  
Bonaventure Ntirugulirwa ◽  
Etienne Zibera ◽  
Daniel Ganszky ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Climate Sensitivity ◽  
Elevation Gradient ◽  
High Elevation ◽  
Dry Season ◽  
Nutrient Ratios ◽  
Wet Season ◽  
Elevation Gradients ◽  
Use Efficiency

Elevation gradients offer excellent opportunities to explore the climate sensitivity of vegetation. Here, we investigated elevation patterns of structural, chemical, and physiological traits in tropical tree species along a 1700–2700 m elevation gradient in Rwanda, central Africa. Two early-successional (Polyscias fulva, Macaranga kilimandscharica) and two late-successional (Syzygium guineense, Carapa grandiflora) species that are abundant in the area and present along the entire gradient were investigated. We found that elevation patterns in leaf stomatal conductance (gs), transpiration (E), net photosynthesis (An), and water-use efficiency were highly season-dependent. In the wet season, there was no clear variation in gs or An with elevation, while E was lower at cooler high-elevation sites. In the dry season, gs, An, and E were all lower at drier low elevation sites. The leaf-to-air temperature difference was smallest in P. fulva, which also had the highest gs and E. Water-use efficiency (An/E) increased with elevation in the wet season, but not in the dry season. Leaf nutrient ratios indicated that trees at all sites are mostly P limited and the N:P ratio did not decrease with increasing elevation. Our finding of strongly decreased gas exchange at lower sites in the dry season suggests that both transpiration and primary production would decline in a climate with more pronounced dry periods. Furthermore, we showed that N limitation does not increase with elevation in the forests studied, as otherwise most commonly reported for tropical montane forests.

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