scholarly journals Persistence at the final stage of volcanic island ontogeny: Abiotic predictors explain native plant species richness on 111 remote Pacific atolls

2018 ◽  
Vol 8 (23) ◽  
pp. 12208-12220 ◽  
Author(s):  
Sébastien Larrue ◽  
Jean-François Butaud ◽  
Curtis C. Daehler ◽  
Stéphane Ballet ◽  
Julien Chadeyron ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Final Stage ◽  
Plant Species Richness ◽  
Native Plant ◽  
Volcanic Island ◽  
Native Plant Species

Native plant species richness on Eastern Polynesia’s remote atolls

2015 ◽  
Vol 40 (1) ◽  
pp. 112-134 ◽  
Author(s):  
Sébastien Larrue ◽  
Jean-François Butaud ◽  
Pascal Dumas ◽  
Stéphane Ballet
Keyword(s):  
Species Richness ◽  
Sea Level ◽  
Plant Species ◽  
Native Species ◽  
Abiotic Factors ◽  
Plant Species Richness ◽  
Native Plant ◽  
Volcanic Island ◽  
Native Plant Species ◽  
Native Species Richness

Which abiotic factors influence the number of native plant species on remote atolls is an important question to understand better the spatial pattern of the species observed on these low and vulnerable coral islands. However, this issue is still very poorly documented, often due to human degradation, partial botanical surveys or the difficult geographic access of remote atolls for researchers. The remote atolls of Eastern Polynesia, which are among the most isolated in the world, are of great interest for studies of native species’ distribution due to their isolation, low human density and urbanisation. In this study, we selected 49 remote atolls of Eastern Polynesia with complete botanical surveys to test the relative influence of eight abiotic factors on native plant species richness (i.e. indigenous and endemic species). Abiotic factors used as potential predictors included atoll area (km2), shoreline length (km), atoll elevation (m) and index of isolation (UNEP), but also the coastal index of the atoll ( Ic), the distance to the nearest similar atoll (km), the distance to the nearest large volcanic island ≥ 1000 km2 (here, Tahiti as a potential stepping-stone island) and the distance to the nearest raised atoll ≥ 15 m a.s.l. (here, Makatea or Henderson as a potential refugium during sea-level highstands). Spearman’s rank correlation, linear regression analysis and frequency diagrams were used to assess the relative influence of these factors on native species richness. No relationship was found between the species richness and the index of isolation or the distance to the nearest similar atoll. Atoll area and distance to the nearest raised atoll of Makatea explained 47.1% and 40%, respectively, of the native species richness variation observed on the remote atolls. The distance to the volcanic island of Tahiti and the coastal index explained 36.9% and 27.3% of the variation, while elevation and shoreline length explained 23.3% and 18.4% of the variation, respectively. Native species richness on the atolls surveyed increased with the increasing atoll area, elevation and shoreline length, but decreased with the increasing distance to the nearest raised atoll of Makatea and the large volcanic island of Tahiti. This supports the view that the spatial pattern of native species richness observed on the remote atolls was strongly influenced by (i) atoll area but also by (ii) the distance to the raised atoll of Makatea, and (iii) the distance to the volcanic island of Tahiti. This finding suggests that the raised atoll may be viewed as a refugium during sea-level highstands while the large volcanic island played the role of stepping-stone island, both islands influencing the dispersal of native species on remote atolls and attenuating the isolation effect in the study area.

The impacts of invasive plant species on the biodiversity of Australian rangelands

2006 ◽  
Vol 28 (1) ◽  
pp. 27 ◽  
Author(s):  
A. C. Grice
Keyword(s):  
Invasive Species ◽  
Species Richness ◽  
Plant Species ◽  
Native Species ◽  
Invasive Plant ◽  
Plant Species Richness ◽  
Native Plant ◽  
Weed Species ◽  
Ecological Processes ◽  
Native Plant Species

Most parts of the Australian rangelands are at risk of invasion by one or more species of non-native plants. The severity of current problems varies greatly across the rangelands with more non-native plant species in more intensively settled regions, in climatic zones that have higher and more reliable rainfall, and in wetter and more fertile parts of rangeland landscapes. Although there is quantitative evidence of impacts on either particular taxonomic groups or specific ecological processes in Australian rangelands, a comprehensive picture of responses of rangeland ecosystems to plant invasions is not available. Research has been focused on invasive species that are perceived to have important effects. This is likely to down play the significance of species that have visually less dramatic influences and ignore the possibility that some species could invade and yet have negligible consequences. It is conceivable that most of the overall impact will come from a relatively small proportion of invasive species. Impacts have most commonly been assessed in terms of plant species richness or the abundance of certain groups of vertebrates to the almost complete exclusion of other faunal groups. All scientific studies of the impacts of invasive species in Australian rangelands have focused on the effects of individual invasive species although in many situations native communities are under threat from a complex of interacting weed species. Invasion by non-native species is generally associated with declines in native plant species richness, but faunal responses are more complex and individual invasions may be associated with increase, decrease and no-change scenarios for different faunal groups. Some invasive species may remain minor components of the vegetation that they invade while others completely dominate one stratum or the vegetation overall.

scholarly journals Shrub removal in reforested post-fire areas increases native plant species richness

2016 ◽  
Vol 374 ◽  
pp. 195-210 ◽  
Author(s):  
Gabrielle N. Bohlman ◽  
Malcolm North ◽  
Hugh D. Safford
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Species Richness ◽  
Native Plant ◽  
Native Plant Species

scholarly journals No universal scale-dependent impacts of invasive species on native plant species richness

2014 ◽  
Vol 10 (1) ◽  
pp. 20130939 ◽  
Author(s):  
Thomas J. Stohlgren ◽  
Marcel Rejmánek
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Invasions ◽  
Plant Species Richness ◽  
Native Plant ◽  
Desert Ecosystems ◽  
Alien Plant ◽  
Native Plant Species ◽  
Wide Range ◽  
The Impact

A growing number of studies seeking generalizations about the impact of plant invasions compare heavily invaded sites to uninvaded sites. But does this approach warrant any generalizations? Using two large datasets from forests, grasslands and desert ecosystems across the conterminous United States, we show that (i) a continuum of invasion impacts exists in many biomes and (ii) many possible species–area relationships may emerge reflecting a wide range of patterns of co-occurrence of native and alien plant species. Our results contradict a smaller recent study by Powell et al. 2013 ( Science 339 , 316–318. ( doi:10.1126/science.1226817 )), who compared heavily invaded and uninvaded sites in three biomes and concluded that plant communities invaded by non-native plant species generally have lower local richness (intercepts of log species richness–log area regression lines) but steeper species accumulation with increasing area (slopes of the regression lines) than do uninvaded communities. We conclude that the impacts of plant invasions on plant species richness are not universal.

Relating pine-litter intrusion to plant-community structure in native eucalypt woodland adjacent to Pinus radiata (Pinaceae) plantations

2007 ◽  
Vol 55 (5) ◽  
pp. 521 ◽  
Author(s):  
Andrew C. Baker ◽  
Brad R. Murray ◽  
Grant C. Hose
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Plant Species ◽  
Plant Community ◽  
Plant Species Richness ◽  
Radiata Pine ◽  
Plant Community Structure ◽  
Native Plant ◽  
Native Plant Species ◽  
Eucalypt Woodland

Radiata pine (Pinus radiata D.Don) plantations are often found in close proximity to vegetation set aside for biodiversity conservation. We examined the intrusive effects of radiata pine beyond the confines of plantations by quantifying the penetration of pine litter (needles, cones, twigs and seeds) and wildings from plantations into adjacent eucalypt woodland in the Jenolan Caves Karst Conservation Reserve (south-eastern Australia). We then investigated the relationship between pine-litter intrusion and plant-community structure in adjacent woodland vegetation. We found significantly higher quantities of pine litter and wildings at all sites adjacent to plantations than at reference woodland sites that were not adjacent to plantations. At adjacent sites, pine litter decreased significantly with increasing distance from plantations. Alarmingly, native plant species richness declined and exotic plant species richness increased with increasing quantities of pine litter. Thus, there were fewer native plant species and more exotics in areas bordering pine plantations. Our findings suggest a potentially important link between the intrusion of pine litter and a loss of native biodiversity and facilitation of exotic-species invasion. We suggest the provision of a buffer zone around plantations in order to minimise intrusive impacts of plantations on native biodiversity.

scholarly journals Native plant species richness in non-native Pinus contorta forest

2016 ◽  
Vol 40 (1) ◽  
pp. 131-136 ◽  
Author(s):  
Clayson Howell ◽  
◽  
Kate McAlpine
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Pinus Contorta ◽  
Plant Species Richness ◽  
Native Plant ◽  
Native Plant Species

Determinants of non-native plant species richness and composition across small Mediterranean islands

2012 ◽  
Vol 14 (12) ◽  
pp. 2559-2572 ◽  
Author(s):  
F. Pretto ◽  
L. Celesti-Grapow ◽  
E. Carli ◽  
G. Brundu ◽  
C. Blasi
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Species Richness ◽  
Native Plant ◽  
Mediterranean Islands ◽  
Native Plant Species
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