scholarly journals Impacts of nitrogen addition on plant species richness and abundance: A global meta‐analysis

2018 ◽  
Vol 28 (3) ◽  
pp. 398-413 ◽  
Author(s):  
Gabriele Midolo ◽  
Rob Alkemade ◽  
Aafke M. Schipper ◽  
Ana Benítez‐López ◽  
Michael P. Perring ◽  
...  
2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
David H. Branson

A continuing challenge in orthopteran ecology is to understand what determines grasshopper species diversity at a given site. In this study, the objective was to determine if variation in grasshopper abundance and diversity between 23 sites in western North Dakota (USA) could be explained by variation in plant species richness and diversity. In this system with relatively low plant diversity, grasshopper species richness and abundance were not significantly associated with plant species richness in either year. Although a number of significant associations between plant diversity and grasshopper diversity were found through regression analyses, results differed greatly between years indicating that plant species richness and diversity did not lead to strong effects on grasshopper diversity metrics. Plant species richness appears to be too coarse grained to lead to accurate predictions of grasshopper species richness in this system dominated by generalist grasshopper species.


2015 ◽  
Vol 19 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Binoj Kumar Shrestha ◽  
Dharma Raj Dangol

This research investigated the invasion of the alien plant Mikania micrantha H.B.K. and its impact on plant species richness and abundance in Chitwan National Park (CNP) forest. Stratified sampling technique was used to collect the information using the nested quadrats in the Mikania invaded and not invaded sites in July 2011. The study revealed that the invasion highly related with the vegetation structure of the habitat; higher the tree crown cover lower the invasion. On the other hand, the invasion in terms of cover percent of Mikania irrespective of the biomass (fresh weight) decreased plant species richness. Species richness showed unimodal response to the Mikania cover percent with the decrease after 35% of Mikania cover. Journal of Institute of Science and Technology, 2014, 19(2): 30-36


2007 ◽  
Vol 85 (3) ◽  
pp. 273-284 ◽  
Author(s):  
L. Dennis Gignac ◽  
Mark R.T. Dale

Forty-one remnants of the aspen-dominated upland forest in three subregions of the dry boreal mixed-wood in Alberta were studied to determine effects of fragment size and shape on native and alien plant species richness and abundance in agro-environments. The percent cover of all vascular plant species was visually estimated in 5 m diameter circular plots along transects that covered the length and the width of each fragment. A subset of 12 of the largest fragments (>900 m2) that had distinct interiors (portions of the fragment >15 m from any edge) was used to measure edge effects on the vegetation. Regression analyses revealed significant positive relationships between species richness and area regardless of the subregion. Species richness stabilized in fragments that were larger than 11 ha. Edges did not affect shrub species richness and only affected herbaceous species richness on west- and south-facing aspects. Shrub abundance decreased and herb abundance increased up to 20 m from the edges regardless of orientation. Edges did not support a different suite of species than interiors, although several species occurred more frequently in the interior than along the edges. Alien species richness and abundance reached their highest values between 5 and 15 m from the edge, and some of those species could be found up to 40 m from the edge. Although larger fragments generally supported more alien species than smaller fragments, the smallest fragments had the greatest number of species per metre squared. Results from this study indicated that it would be preferable to conserve larger woodlots rather then several smaller woodlots on the landscape.


2014 ◽  
Vol 19 (3) ◽  
Author(s):  
Cristina P. Vila-Ruiz ◽  
Elvia Meléndez-Ackerman ◽  
Raul Santiago-Bartolomei ◽  
Diana Garcia-Montiel ◽  
Lourdes Lastra ◽  
...  

2014 ◽  
Vol 36 (3) ◽  
pp. 309
Author(s):  
D. M. Orr ◽  
D. G. Phelps

The occurrence of interstitial species in Astrebla grasslands in Australia are influenced by grazing and seasonal rainfall but the interactions of these two influences are complex. This paper describes three studies aimed at determining and explaining the changes in plant species richness and abundance of the interstitial species in a long-term sheep utilisation experiment in an Astrebla grassland in northern Queensland. In the first study, increasing utilisation increased the frequency of Dactyloctenium radulans (Button grass) and Brachyachne convergens (Downs couch) and reduced that of Streptoglossa adscendens (Mint bush). In the second study, seasonal rainfall variation between 1984 and 2009 resulted in large annual differences in the size of the seed banks of many species, but increasing utilisation consistently reduced the seed bank of species such as Astrebla spp. and S. adscendens and increased that of species such as B. convergens, D. radulans, Amaranthus mitchellii (Boggabri) and Boerhavia sp. (Tar vine). In the third study, the highest species richness occurred at the lightest utilisation because of the presence of a range of palatable forbs, especially legumes. Species richness was reduced as utilisation increased. Species richness in the grazing exclosure was low and similar to that at the heaviest utilisation where there was a reduction in the presence of palatable forb species. The pattern of highest species richness at the lightest grazing treatment was maintained across three sampling times, even with different amounts of seasonal rainfall, but there was a large yearly variation in both the density and frequency of many species. It was concluded that the maintenance of highest species richness at the lightest utilisation was not aligned with other data from this grazing experiment which indicated that the maximum sustainable wool production occurred at moderate utilisation.


2013 ◽  
Vol 35 (1) ◽  
pp. 17 ◽  
Author(s):  
D. M. Orr ◽  
D. G. Phelps

The occurrence of interstitial species in Astrebla grasslands in Australia are influenced by grazing and seasonal rainfall but the interactions of these two influences are complex. This paper describes three studies aimed at determining and explaining the changes in plant species richness and abundance of the interstitial species in a long-term sheep utilisation experiment in an Astrebla grassland in northern Queensland. In the first study, increasing utilisation increased the frequency of Dactyloctenium radulans (Button grass) and Brachyachne convergens (Downs couch) and reduced that of Streptoglossa adscendens (Mint bush). In the second study, seasonal rainfall variation between 1984 and 2009 resulted in large annual differences in the size of the seed banks of many species, but increasing utilisation consistently reduced the seed bank of species such as Astrebla spp. and S. adscendens and increased that of species such as B. convergens, D. radulans, Amaranthus mitchellii (Boggabri) and Boerhavia sp. (Tar vine). In the third study, the highest species richness occurred at the lightest utilisation because of the presence of a range of palatable forbs, especially legumes. Species richness was reduced as utilisation increased. Species richness in the grazing exclosure was low and similar to that at the heaviest utilisation where there was a reduction in the presence of palatable forb species. The pattern of highest species richness at the lightest grazing treatment was maintained across three sampling times, even with different amounts of seasonal rainfall, but there was a large yearly variation in both the density and frequency of many species. It was concluded that the maintenance of highest species richness at the lightest utilisation was not aligned with other data from this grazing experiment which indicated that the maximum sustainable wool production occurred at moderate utilisation.


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