scholarly journals Abiotic conditions shape the relationship between indigenous and exotic species richness in a montane biodiversity hotspot

Plant Ecology ◽  
2021 ◽  
Vol 222 (4) ◽  
pp. 421-432
Author(s):  
Manuel R. Popp ◽  
Jesse M. Kalwij
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Biotic Resistance ◽  
Plant Invasions ◽  
Biodiversity Hotspot ◽  
Indigenous Species ◽  
Strong Positive Correlation ◽  
Montane Biodiversity ◽  
Shallow Soils ◽  
Biotic Acceptance

AbstractMontane ecosystems are more prone to invasions by exotic plant species than previously thought. Besides abiotic factors, such as climate and soil properties, plant-plant interactions within communities are likely to affect the performance of potential invaders in their exotic range. The biotic resistance hypothesis predicts that high indigenous species richness hampers plant invasions. The biotic acceptance hypothesis, on the other hand, predicts a positive relationship between indigenous and exotic species richness. We tested these two hypotheses using observational data along an elevational gradient in a southern African biodiversity hotspot. Species composition data of indigenous and exotic plants were recorded in 20 road verge plots along a gradient of 1775–2775 m a.s.l. in the Drakensberg, South Africa. Plots were 2 × 50 m in size and positioned at 50 m elevational intervals. We found a negative correlation between indigenous and exotic richness for locations with poorly developed mineral soils, suggesting biotic resistance through competitive interactions. A strong positive correlation for plots with very shallow soils at high elevations indicated a lack of biotic resistance and the possibility of facilitating interactions in harsher environments. These results suggest that biotic resistance is restricted to the lower and mid elevations while biotic acceptance prevails in presence of severe abiotic stress, potentially increasing the risk of plant invasions into montane biodiversity hotspots.

scholarly journals Species richness and interacting factors control invasibility of a marine community

2015 ◽  
Vol 282 (1812) ◽  
pp. 20150439 ◽  
Author(s):  
M. L. Marraffini ◽  
J. B. Geller
Keyword(s):  
Species Richness ◽  
Native Species ◽  
Biotic Resistance ◽  
Marine Species ◽  
Indigenous Species ◽  
Total Species Richness ◽  
Species Recruitment ◽  
Non Indigenous Species ◽  
Total Species

Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants , 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment.

scholarly journals Environmental harshness drives spatial heterogeneity in biotic resistance

NeoBiota ◽  
2018 ◽  
Vol 40 ◽  
pp. 87-105 ◽  
Author(s):  
Basil V. Iannone III ◽  
Kevin M. Potter ◽  
Qinfeng Guo ◽  
Insu Jo ◽  
Christopher M. Oswalt ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Heterogeneity ◽  
Biotic Resistance ◽  
Tree Height ◽  
Plant Invasions ◽  
Forest Community ◽  
Species Invasions ◽  
Native Trees ◽  
Evolutionary Relatedness ◽  
Maximum Tree Height

Ecological communities often exhibit greater resistance to biological invasions when these communities consist of species that are not closely related. The effective size of this resistance, however, varies geographically. Here we investigate the drivers of this heterogeneity in the context of known contributions of native trees to the resistance of forests in the eastern United States of America to plant invasions. Using 42,626 spatially referenced forest community observations, we quantified spatial heterogeneity in relationships between evolutionary relatedness amongst native trees and both invasive plant species richness and cover. We then modelled the variability amongst the 91 ecological sections of our study area in the slopes of these relationships in response to three factors known to affect invasion and evolutionary relationships –environmental harshness (as estimated via tree height), relative tree density and environmental variability. Invasive species richness and cover declined in plots having less evolutionarily related native trees. The degree to which they did, however, varied considerably amongst ecological sections. This variability was explained by an ecological section’s mean maximum tree height and, to a lesser degree, SD in maximum tree height (R2GLMM = 0.47 to 0.63). In general, less evolutionarily related native tree communities better resisted overall plant invasions in less harsh forests and in forests where the degree of harshness was more homogenous. These findings can guide future investigations aimed at identifying the mechanisms by which evolutionary relatedness of native species affects exotic species invasions and the environmental conditions under which these effects are most pronounced.

scholarly journals Accounting for the indirect area effect in stacked species distribution models to map species richness in a montane biodiversity hotspot

2015 ◽  
Vol 21 (11) ◽  
pp. 1329-1338 ◽  
Author(s):  
Robin Pouteau ◽  
Élise Bayle ◽  
Élodie Blanchard ◽  
Philippe Birnbaum ◽  
Jean-Jérôme Cassan ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Distribution ◽  
Species Distribution Models ◽  
Biodiversity Hotspot ◽  
Distribution Models ◽  
Area Effect ◽  
Montane Biodiversity

Bird species richness and abundance in riparian vegetation invaded by exotic Reynoutria spp.

Biologia ◽  
2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Lenka Hajzlerová ◽  
Jiří Reif
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Riparian Vegetation ◽  
Bird Species ◽  
Plant Invasions ◽  
Alien Plant ◽  
Bird Species Richness ◽  
River Bank ◽  
Management Actions ◽  
Acrocephalus Palustris

AbstractImpacts of invasive alien plant species are threatening biodiversity worldwide and thus it is important to assess their effects on particular groups of organisms. However, such impacts were studied mostly in case of plant or invertebrate communities and our understanding the response of vertebrate species to plant invasions remains incomplete. To improve our knowledge in this respect, we studied bird communities in riparian vegetation along the rivers with different levels of Reynoutria spp. invasion in the Czech Republic. These findings will be interesting for basic ecology enhancing our knowledge of consequences of plant invasions, as well as for conservation practice. We surveyed understory bird species in 26 vegetation blocks along parts of three rivers running from the Beskydy Mountains in spring 2011. We used principal component analysis to assess vegetation structure of particular blocks and the first axis ordinated the blocks according to the degree of invasion by Reynoutria spp. Using generalized linear mixed-effects models we found that counts of Motacilla cinerea, Cinclus cinclus and Sylvia borin, as well as the total bird species richness, significantly decreased with increasing degree of Reynoutria spp. invasion, while Acrocephalus palustris showed the opposite pattern. These results suggest that Reynoutria spp. impacts negatively on the species strictly bond with river banks and habitats specialists, whereas habitat generalist species like Sylvia atricapilla were not affected. Preference of Acrocephalus palustris for Reynoutria spp. corroborates affinity of this species to large invasive herbs observed also in other studies. Our study showed that Reynoutria spp. invasion can reduce species richness of understory birds in riparian communities. Although the distribution of this plant species is still quite limited in central Europe, our results suggest that its more widespread occurrence could potentially threat some river bank bird species. Therefore, we urge for development of management actions that will act counter the Reynoutria spp. invasion.

Interactive effects of source and recipient habitats on plant invasions: distribution of exotic species in Chile

2015 ◽  
Vol 21 (6) ◽  
pp. 609-619 ◽  
Author(s):  
Miguel A. Casado ◽  
Belén Acosta-Gallo ◽  
Laura Sánchez-Jardón ◽  
Irene Martín-Forés ◽  
Isabel Castro ◽  
...  
Keyword(s):  
Exotic Species ◽  
Plant Invasions ◽  
Interactive Effects

Palm house – biodiversity hotspot or risk of invasion? Aquatic invertebrates: The special case of Monogononta (Rotifera) under greenhouse conditions

Biologia ◽  
2015 ◽  
Vol 70 (1) ◽  
Author(s):  
Małgorzata Kolicka ◽  
Marcin Krzysztof Dziuba ◽  
Krzysztof Zawierucha ◽  
Natalia Kuczyńska–Kippen ◽  
Lech Kotwicki
Keyword(s):  
Species Richness ◽  
New Species ◽  
Aquatic Plants ◽  
Aquatic Invertebrates ◽  
Biodiversity Hotspot ◽  
Simpson Index ◽  
Mesocyclops Leuckarti ◽  
Euchlanis Dilatata ◽  
Special Case ◽  
Stable Populations

AbstractGreenhouses form favourable conditions for establishing stable populations of native as well as invasive alien microinvertebrates. Investigations of palm houses have a long tradition and native, alien and new species for science have been found in many of them. The examined pond and some microreservoirs in Bromeliaceae and Agavoideae in Pozna´n Palm House (Poland) sampled in 2012, appeared to contain representatives of Rotifera (64 species), Copepoda (2 species), Polychaeta, Acari and Insecta larvae. The most abundant Rotifera species were: Anuraeopsis fissa Gosse, 1851, Ascomorpha ecaudis Perty 1850, Euchlanis dilatata Ehrenberg, 1832, Pompholyx sulcata Hudson, 1885 and Trichocerca rousseleti Voight, 1902. Moreover, rotifers considered to be rare in Poland, i.e., Asplanchna herricki De Guerne, 1888, Collotheca pelagica Rousselet, 1893, Colurella sulcata Stenroos, 1898, Gastropus minor Rousselet, 1892 were also detected in Pozna´n Palm House. Two recorded Copepoda species were Phyllognathopus viguieri (Maupas, 1892) found in agave microreservoirs and Mesocyclops leuckarti (Claus, 1857) found in reservoir with aquatic plants. For biodiversity evaluation of rotifers Margalef’s and Shannon-Wiener’s indexes were used and in order to determine species richness the Simpson index was calculated. Additionally, a complete list of all aquatic invertebrates is presented, i.e., Plathelmintes (11 species), Nemeretea (2 species), Oligochatea (13 taxa), Polychaeta (7 species), Gastrotricha (13 taxa) and Copepoda (1 species) previously recorded in Pozna´n Palm House. To sum up, Palm houses create a convenient habitat for a prevalence of native and introduced invertebrates and are a putative source of alien species, possibly facilitating their release to the environment.

scholarly journals Plant invasions: merging the concepts of species invasiveness and community invasibility

2006 ◽  
Vol 30 (3) ◽  
pp. 409-431 ◽  
Author(s):  
David M. Richardson ◽  
Petr Pyšek
Keyword(s):  
Biotic Resistance ◽  
Propagule Pressure ◽  
Plant Invasions ◽  
Invasion Ecology ◽  
Natural Ecosystems ◽  
Long Distance ◽  
Fluctuating Resources ◽  
Species Invasiveness ◽  
Tens Rule ◽  
New Research

This paper considers key issues in plant invasion ecology, where findings published since 1990 have significantly improved our understanding of many aspects of invasions. The review focuses on vascular plants invading natural and semi-natural ecosystems, and on fundamental ecological issues relating to species invasiveness and community invasibility. Three big questions addressed by the SCOPE programme in the 1980s (which species invade; which habitats are invaded; and how can we manage invasions?) still underpin most work in invasion ecology. Some organizing and unifying themes in the field are organism-focused and relate to species invasiveness (the tens rule; the concept of residence time; taxonomic patterns and Darwin’s naturalization hypothesis; issues of phenotypic plasticity and rapid evolutionary change, including evolution of increased competitive ability hypothesis; the role of long-distance dispersal). Others are ecosystem-centred and deal with determinants of the invasibility of communities, habitats and regions (levels of invasion, invasibility and propagule pressure; the biotic resistance hypothesis and the links between diversity and invasibility; synergisms, mutualisms, and invasional meltdown). Some theories have taken an overarching approach to plant invasions by integrating the concepts of species invasiveness and community invasibility (a theory of seed plant invasiveness; fluctuating resources theory of invasibility). Concepts, hypotheses and theories reviewed here can be linked to the naturalization-invasion continuum concept, which relates invasion processes with a sequence of environmental and biotic barriers that an introduced species must negotiate to become casual, naturalized and invasive. New research tools and improved research links between invasion ecology and succession ecology, community ecology, conservation biology and weed science, respectively, have strengthened the conceptual pillars of invasion ecology.

scholarly journals Basic and Grade Stress for Some Timber in Sarawak

2011 ◽  
Vol 2 (2) ◽  
pp. 35-38
Author(s):  
Gaddafi Ismaili ◽  
Badorul Hisham Abu Bakar ◽  
Khairul Khuzaimah Abdul Rahim
Keyword(s):  
Exotic Species ◽  
Modulus Of Elasticity ◽  
Acacia Mangium ◽  
Wood Properties ◽  
Strength Properties ◽  
Indigenous Species ◽  
Medium Density ◽  
Compression Stress ◽  
Strength Group ◽  
Fast Growing Species

Strength properties’ tests are conducted in the small clear sample. This paper aim to acquire the basic and grade stresses of some fast growing species thus identifies its strength group. Thus, the information of wood properties from different species and condition are acquired from strength property's test. The required information namely, bending parallel to the grain, compression stress parallel to grain, shear parallel to grain and modulus of elasticity. The condition of the trees which is referred to green and air-dry condition. Three different species which are referred to exotic species of Acacia mangium and indigenous species of Aras. The results from the study indicated that, Acacia mangium classified under the strength group SG5, whilst Aras was classified under the strength group SG7. The timber is of medium density Light Hardwood ranging from 0.37-0.52g/cm3 air-dry condition.

scholarly journals COMPARISON ON VEGETATION COMPOSITION AND STRUCTURE OF EXCLOSURES VS. OPEN GRAZING LANDS IN NORTHERN ETHIOPIA

2021 ◽  
Vol 9 (8) ◽  
pp. 70-99
Author(s):  
Samson Shimelse Jemaneh
Keyword(s):  
Population Structure ◽  
Species Richness ◽  
Plant Species ◽  
Woody Species ◽  
Soil Parameters ◽  
Northern Ethiopia ◽  
Indigenous Species ◽  
Regeneration Status ◽  
Composition And Structure ◽  
Grazing Lands

This study was conducted with the objectives of study investigates, compare, and try to describe the floristic composition and structure of the vegetation of exclosures and open grazing lands. A stratified preferential sampling design technique with flexible systematic model was used for data collection. Data on vegetation and environmental parameters were gathered from 120 quadrants (90 from restorations or exclosures of different ages and 30 from adjacent open grazing lands), of 20 m x 20 m (400 m2) size. Species richness and the presence or absence of herbaceous plants were recorded like soil samples in a 2 m x 2 m (4 m2) subplot inside each main quadrant from five points, one at each corner and one at the center.  A total of 142 plant species belonging to 118 genera and 52 families were identified. All exclosures displayed higher plant species richness, diversity, and aboveground standing biomass compared to the adjacent open grazing lands. Consideration of edaphic (e.g. soil total nitrogen, available phosphorus, CEC, exchangeable bases, soil pH and soil texture) and site (e.g. Stoniness, Grazing) variables will help to optimize the selection of areas for the establishment of future exclosures. Moreover, our study suggests that with time exclosures may increasingly obtain an important role as refugees and species pool similar to church forests and should be protected and managed in a sustainable manner. However, economic and social impacts of exclosures should be included in feasibility studies before establishing exclosures in the future.  Altitude, Grazing and some soil parameters like Mg were the major environmental factors in the division of the vegetation into plant community types. The result of the frequency distribution of woody species showed a high proportion of small-sized individuals in the lower diameter classes indicating good recruitment potential of the forest patches and the rare occurrence of large individuals. Such trend was probably caused by past disturbance of the original vegetation resulting in a succession of secondary vegetation. In addition, the analysis of species population structure indicated that some tree species had abnormal population structure with no or few individuals at lower size classes. Moreover, assessment of regeneration status on the basis of age classes indicated that significant proportion of woody species were represented by few or no seedlings, entailing that they were under threat. Substantial numbers of forest species were found to have irregular population structure and are in reduced regeneration status. To prevent local extinction of these species, present efforts of nursery establishment and plantation of indigenous species in the exclosures should be strengthened and extended.

scholarly journals Regional climate and local-scale biotic acceptance explain native–exotic richness relationships in Australian annual plant communities

2018 ◽  
Vol 285 (1886) ◽  
pp. 20181328 ◽  
Author(s):  
Isaac. R. Towers ◽  
John. M. Dwyer
Keyword(s):  
Exotic Species ◽  
Structural Equation ◽  
Spatial Scales ◽  
Regional Climate ◽  
Soil Surface ◽  
Equation Model ◽  
Annual Plant ◽  
Regional Temperature ◽  
Neighbourhood Scale ◽  
Biotic Acceptance

Native and exotic species richness is expected to be negatively related at small spatial scales where individuals interact, and positive at larger spatial scales as a greater variety of habitats are sampled. However, a range of native–exotic richness relationships (NERRs) have been reported, including positive at small scales and negative at larger scales. We present a hierarchical metacommunity framework to explain how contrasting NERRs may emerge across scales and study systems, and then apply this framework to NERRs in an invaded winter annual plant system in southwest Western Australia. We analysed NERRs at increasing spatial scales from neighbourhoods (0.09 m 2 ) to communities (225 m 2 ) to metacommunities (greater than 10 ha) within a multilevel structural equation model. In contrast to many previous studies, native and exotic richness were positively related at the neighbourhood scale and were not significantly associated at larger scales. Heterogeneity in soil surface properties was weakly, but positively, associated with native and exotic richness at the community scale. Metacommunity exotic richness increased strongly with regional temperature and moisture availability, but relationships for native richness were negative and much weaker. Thus, we show that neutral NERRs can emerge at larger scales owing to differential climatic filtering of native and exotic species pools.

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