The influence of aboveground and belowground species composition on spatial turnover in nutrient pools in alpine grasslands

Author(s):  
Xin Jing ◽  
Case M. Prager ◽  
Litong Chen ◽  
Haiyan Chu ◽  
Nicholas J. Gotelli ◽  
...  
1983 ◽  
Vol 7 (4) ◽  
pp. 208-212 ◽  
Author(s):  
Robert N. Muller

Abstract An old-growth forest and a 35-year-old, second-growth forest on the Cumberland Plateau were studied to compare species composition and structure. Species composition and total basal area of the two stands did not differ, although total stand density was 19 percent lower and basal area of commercial species was 25 percent higher in the old-growth than in the second-growth stand. Analysis of size-class distributions showed that both stands were best represented by an inverse J-shaped distribution, which best describes old-age stands. The rapid regeneration of the second-growth stand seems to be the result of minimal disturbance to accumulated nutrient pools in the soil. The importance of these accumulated nutrient pools and implications for forest management on the Cumberland Plateau are discussed.


2005 ◽  
Vol 32 (5) ◽  
pp. 377 ◽  
Author(s):  
J. C. Z. Woinarski ◽  
R. J. Williams ◽  
O. Price ◽  
B. Rankmore

This paper provides an introduction to the ecological fabric of northern Australia, described here as being a land characterised by extreme climatic seasonality and largely devoid of marked topographic features. Largely as a result of the latter trait, many species have extensive geographic ranges, and the spatial turnover in species composition is extremely limited. Somewhat counter-intuitively, these two traits can be accommodated by organisms only through reliance on critical, but often subtle, landscape variation. We present some preliminary models for Gouldian finch (Erythrura gouldiae) and black-footed tree-rat (Mesembriomys gouldii) to illustrate patterns of variation in their resource availability, and the consequences of such variation. We discuss briefly some studies that have attempted to integrate, or at least consider, these elements.


2005 ◽  
Vol 81 (1) ◽  
pp. 61-72 ◽  
Author(s):  
S L Hunt ◽  
A M Gordon ◽  
D M Morris

This study investigated relationships between understory vegetation and nutrient pools in managed stands of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] BSP) in the Lake Nipigon region of northern Ontario. The species composition, biomass, and nutrient pool sizes in the understory vegetation, as well as biomass and nutrient pools in trees and soils, were determined in 16 managed stands ranging in age from 10 to 53 years since establishment and one mature, natural stand. Patterns of above-ground biomass accumulation in understory vegetation varied with overstory tree species and general site type (dry, sandy soils, or mesic, finer-textured soils). Understory vegetation contributed little (0.3 to 2.6%) to total above-ground organic matter (live biomass plus forest floor) but accounted for higher proportions of total above-ground nutrient pools (e.g., 0.7 to 3.4% of N; 3.2 to 11.7% of K) and net primary productivity (1.2 to 21.2%). The species composition of the understory vegetation was strongly related to stand basal area as well as to concentrations of nutrients (N, P, K, Ca, Mg) in the forest floor and mineral soil. The greatest amount of change in vegetation community composition occurred from the pre-to post-canopy closure stages of stand development; fewer differences were observed among stands of a given species and site type 35 to 50 years after establishment. The effects of silvicultural practices were detected in certain stands 35 years after establishment; for example the most severely treated (bladed and thinned) jack pine stand differed from other stands of similar age and soils with its Cladina/Vaccinium-dominated understory, and large amounts of biomass in the moss/lichen stratum. The understory vegetation communities in other managed jack pine stands, by 35 to 50 years, were similar to that of the mature, natural stand, indicating resilience to silvicultural disturbances. Silviculture may have lasting effects on understory vegetation biomass and species composition through its effects on stand basal area, overstory species, and soil nutrients. This research serves as baseline information for further studies into the ecology of managed stands in northern Ontario. Key words: understory, nutrients, managed forests, jack pine, black spruce, canonical correspondence analysis


2020 ◽  
Vol 42 (1) ◽  
pp. 32-48
Author(s):  
LOVANOMENJANAHARY MARLINE ◽  
TERRY A. J. HEDDERSON ◽  
CLAUDINE AH-PENG

Understanding spatial variation in species composition of different communities is key to understanding the processes that generate and maintain biodiversity. The partitioning of diversity into hierarchical scale-related components is an interesting approach to quantitatively defining the overall net biodiversity from hierarchically scaled studies and is a useful method in studies of conservation biology and restoration. This paper deals with the additive partitioning of the overall diversity and the partitioning of beta-diversity of epiphytic bryophytes along an elevational gradient in Madagascar. The aim is to describe the variation in species composition between sites and to elucidate why different species occur in different communities in the Marojejy National Park (250–2050 m). We looked at the contribution of α and β diversity to total diversity were calculated from four hierarchical scales: microhabitat (50 cm2), quadrat (4 m2), plot (100 m2) and elevation (every 200 m). Furthermore, we documented how the two components of beta-diversity (turnover and nestedness) are influenced by variation in elevation. Our result suggests that more variation in species richness was found within the elevational scales, than within microplot scales, confirming that beta diversity at the largest sampling scale is the largest contributor to the total diversity. It indicates that bryophyte species among sample within each level are a subsample of the same species pool. This study shows evidence that the beta-diversity of epiphytic bryophyte assemblages is dominated by high spatial turnover due to recruitment of new species along the Marojejy transect, a clear pattern for mountains.


2012 ◽  
Vol 279 (1748) ◽  
pp. 4772-4777 ◽  
Author(s):  
Benjamin Baiser ◽  
Julian D. Olden ◽  
Sydne Record ◽  
Julie L. Lockwood ◽  
Michael L. McKinney

Human activities have reorganized the earth's biota resulting in spatially disparate locales becoming more or less similar in species composition over time through the processes of biotic homogenization and biotic differentiation, respectively. Despite mounting evidence suggesting that this process may be widespread in both aquatic and terrestrial systems, past studies have predominantly focused on single taxonomic groups at a single spatial scale. Furthermore, change in pairwise similarity is itself dependent on two distinct processes, spatial turnover in species composition and changes in gradients of species richness. Most past research has failed to disentangle the effect of these two mechanisms on homogenization patterns. Here, we use recent statistical advances and collate a global database of homogenization studies (20 studies, 50 datasets) to provide the first global investigation of the homogenization process across major faunal and floral groups and elucidate the relative role of changes in species richness and turnover. We found evidence of homogenization (change in similarity ranging from −0.02 to 0.09) across nearly all taxonomic groups, spatial extent and grain sizes. Partitioning of change in pairwise similarity shows that overall change in community similarity is driven by changes in species richness. Our results show that biotic homogenization is truly a global phenomenon and put into question many of the ecological mechanisms invoked in previous studies to explain patterns of homogenization.


1985 ◽  
Vol 63 (11) ◽  
pp. 2077-2080
Author(s):  
Dale R. Seip ◽  
Fred L. Bunnell

Species composition and herbage production were determined for different range types used by ungulates in northern British Columbia. In addition, the effect of N fertilization on alpine grasslands was measured. Fire-induced subalpine grasslands produced much more herbage than other range types. Graminoid production, but not forb production, was greater in wet growing seasons. Fertilization of alpine ranges with 17–35 kg N/ha did not increase the herbage production.


2020 ◽  
Vol 12 (15) ◽  
pp. 2480 ◽  
Author(s):  
Yu Qin ◽  
Yi Sun ◽  
Wei Zhang ◽  
Yan Qin ◽  
Jianjun Chen ◽  
...  

Plateau pika (Ochotona curzoniae, hereafter pika) is considered to exert a profound impact on vegetation species diversity of alpine grasslands. Great efforts have been made at mound or quadrat scales; nevertheless, there is still controversy about the effect of pika. It is vital to monitor vegetation species composition in natural heterogeneous ecosystems at a large scale to accurately evaluate the real role of pika. In this study, we performed field survey at 55 alpine grassland sites across the Shule River Basin using combined methods of aerial photographing using an unmanned aerial vehicle (UAV) and traditional ground measurement. Based on our UAV operation system, Fragmentation Monitoring and Analysis with aerial Photography (FragMAP), aerial images were acquired. Plot-scale vegetation species were visually identified, and total pika burrow exits were automatically retrieved using the self-developed image processing software. We found that there were significant linear relationships between the vegetation species diversity indexes obtained by these two methods. Additionally, the total number of identified species by the UAV method was 71, which was higher than the Quadrat method recognition, with the quantity of 63. Our results indicate that the UAV was suitable for long-term repeated monitoring vegetation species composition of multiple alpine grasslands at plot scale. With the merits of UAV, it confirmed that pika’s disturbance belonged to the medium level, with the density ranging from 30.17 to 65.53 ha−1. Under this density level, pika had a positive effect on vegetation species diversity, particularly for the species richness of sedge and forb. These findings conclude that the UAV was an efficient and economic tool for species monitoring to reveal the role of pika in the alpine grasslands.


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