The effects of clonal integration on the responses of plant species to habitat loss and habitat fragmentation

2018 ◽  
Vol 384 ◽  
pp. 290-295
Author(s):  
Zhixia Ying ◽  
Gang Ge ◽  
Yongjie Liu
Oryx ◽  
2011 ◽  
Vol 45 (2) ◽  
pp. 172-179 ◽  
Author(s):  
Sugeng Budiharta ◽  
Didik Widyatmoko ◽  
Irawati ◽  
Harry Wiriadinata ◽  
Rugayah ◽  
...  

AbstractThe processes that threaten 240 Indonesian threatened plants were identified and categorized based on a comprehensive review of the published literature and elicitation of information from experts. Intrinsic biological factors and habitat loss are the major causes of plant endangerment in Indonesia (affecting 83 and 82% of species respectively), followed by overexploitation (64%) and natural factors (6%). The dominant threats vary between major plant groups, with habitat loss being particularly important for palms and trees, and biological factors important for orchids. For all studied plant species three sets of inter-related threatening processes (threat syndromes) were identified that differed among the major plant groups. By identifying and evaluating the processes that threaten plants in Indonesia we provide knowledge to guide their future conservation.


2000 ◽  
Vol 78 (6) ◽  
pp. 786-797 ◽  
Author(s):  
A R Haig ◽  
U Matthes ◽  
D W Larson

Plant species richness, diversity, and some aspects of species composition were measured on natural limestone cliff fragments of varying size within the Niagara Escarpment Biosphere Reserve, Canada. This information was collected because knowledge about how different components of community structure change in response to natural fragmentation may permit the prediction of the effects of future anthropogenic fragmentation. The number and relative abundance of vascular plant, bryophyte, and lichen species were determined on cliff fragments that varied in area from 185 to 126 000 m2. Latitude, aspect, percent available photosynthetically active radiation on the cliff face, distance from the nearest neighbouring cliff, and length of the nearest neighbouring cliff were also measured. Regression analysis was used to test for a significant relationship between fragment area and diversity of vascular plants, bryophytes, and lichens both separately and combined. Multiple regression with all subsets selection was used to find the best predictors of species richness from among all variables measured for the 21 cliff fragments. Multivariate analyses were used to study the effect of fragmentation on the structure of the vegetation as a whole. The results showed no significant relationship between cliff fragment area and richness or diversity for vascular plants and bryophytes, and only a marginally significant increase in richness with area for lichens. The multivariate analyses also showed that only one community type exists, and that its structure mainly varies as a function of latitude. These results indicate that very small fragments of cliff face can support a similar plant biodiversity as do large continuous portions of the Niagara Escarpment.Key words: habitat fragmentation, plant species richness, lichens, bryophytes, cliff vegetation.


2010 ◽  
Vol 16 (6) ◽  
pp. 941-951 ◽  
Author(s):  
Alessio Mortelliti ◽  
Stefano Fagiani ◽  
Corrado Battisti ◽  
Dario Capizzi ◽  
Luigi Boitani

2021 ◽  
Author(s):  
◽  
Franz-Rudolf Schnitzler

<p>Habitat fragmentation and the resulting decline in biodiversity through the loss of habitat are thought to be the main threat to insect extinctions. According to the trophic level hypothesis, habitat fragmentation affects parasitoids more severely than their herbivorous hosts. Parasitoids also may be correlated with plant species richness, because plants host a variety of phytophagous insects acting as hosts for parasitoids, or plants provide food or act as shelter for parasitoids. In this study, the effects of the forest fragment properties; area, isolation, percentage of residential area surrounding focal fragments and plant richness on parasitic wasps and their interactions were examined. These fragmentation effects were examined in 10 urban native bush remnants in the Wellington and Hutt Valley region of the lower North Island, New Zealand. Fragmentation effects on species abundance, richness and diversity and on community assemblages were examined for the wasp families Ichneumonidae, Pompilidae and Proctotrupidae. Correlations between beta diversity of the plant community and the parasitoid community were analysed and the study investigated whether individual parasitoid occurrences can be predicted by the range of their host's host plants. This study focused on interactions between the kawakawa moth larva Cleora scriptaria, its primary host plant Macropiper excelsum and the parasitism rates by two parasitoids Aleiodes declanae (an endemic species) and Meteorus pulchricornis (an exotic species) and the herbivory caused by C. scriptaria larvae. In addition to interaction responses to forest fragmentation properties, interaction responses were also examined with respect to the properties of the plot and individual plant. Individual species showed different trends in response to the fragmentation properties, making interpretation of a general community response difficult. The abundance, richness and diversity of small-bodied parasitoids were inversely related to increasing area and plant species richness. Parasitoid community composition changed with fragment isolation and plant species richness. Ichneumonidae strongly responded to isolation in one year, whereas the Pompilidae responded to plant species richness. The Proctotrupidae community structure showed no response to any of the fragmentation properties. Correlations between plant and parasitoid community structures were not significant and individual parasitoid-plant associations were weak and inconclusive. Parasitism rates for A. declanae were significantly higher in more isolated fragments with smaller trees, and were negatively affected by overall parasitism rates, more so in isolated fragments. Parasitism rates by M. pulchricornis responded positively to larval densities and declined with increasing plant richness. Herbivory was positively related to the abundance of M. excelsum, tree size and larval density. The current study provides evidence that the forest fragment properties examined are, on their own, not always sufficient predictors of community structure and interactions for parasitoids. Aspects of the results from this thesis conflict with the trophic-level hypothesis with species responding in a negative or positive way, or not responding at all to forest fragmentation effects. The findings of this thesis support to conserving species diversity by maintaining and enhancing all types of existing forest fragments to prevent species extinctions.</p>


2020 ◽  
Vol 42 (2) ◽  
pp. 152
Author(s):  
Stephen M. Jackson ◽  
Mark Parsons ◽  
Marcus Baseler ◽  
David Stanton

Key threatening processes to biodiversity include habitat loss and fragmentation, with populations restricted to small fragments of habitat being more prone to extinction. The mahogany glider (Petaurus gracilis) is endemic to sclerophyll woodland forests between Tully and Ingham in north Queensland and is one of Australia’s most endangered arboreal mammals due to these processes. The aim of this study was to identify the degree of habitat fragmentation of the remaining remnant vegetation of the mahogany glider, identify subpopulations within its distribution and identify key wildlife corridors for restoration to facilitate the movement of this species within and between subpopulations. Ten glider subpopulations, spread over 998 habitat fragments, were identified, of which only five subpopulations may currently be considered to be viable. To assist in providing habitat connectivity between and within the subpopulations, 55 corridors were identified for restoration that had an average length of 8.25 km. The average number of gaps greater than 30 m was 3.4 per corridor, with the average length of these gaps being 523 m. This study confirmed a high degree of habitat fragmentation across the distribution of the mahogany glider and highlighted the need to strengthen the remaining subpopulations by restoring habitat connectivity between the remaining habitat fragments.


2014 ◽  
Author(s):  
Benjamin Zuckerberg ◽  
Matt Carling ◽  
Roi Dor ◽  
Elise Ferree ◽  
Garth Spellman ◽  
...  

Habitat fragmentation is a major driver of environmental change affecting wildlife populations across multiple levels of biological diversity. Much of the recent research in landscape genetics has focused on quantifying the influence of fragmentation on genetic variation among populations, but questions remain as to how habitat loss and configuration influences within-population genetic diversity. Habitat loss and fragmentation might lead to decreases in genetic diversity within populations, which might have implications for population persistence over multiple generations. We used genetic data collected from populations of three species occupying forested landscapes across a broad geographic region: Mountain Chickadee (Poecile gambeli; 22 populations), White-breasted Nuthatch (Sitta carolinensis; 13 populations) and Pygmy Nuthatch (Sitta pygmaea; 19 populations) to quantify patterns of haplotype and nucleotide diversity across a range of forest fragmentation. We predicted that fragmentation effects on genetic diversity would vary depending on dispersal capabilities and habitat specificity of the species. Forest aggregation and the variability in forest patch area were the two strongest landscape predictors of genetic diversity. We found higher haplotype diversity in populations of P. gambeli and S. carolinensis inhabiting landscapes characterized by lower levels of forest fragmentation. Conversely, S. pygmaea demonstrated the opposite pattern of higher genetic diversity in fragmented landscapes. For two of the three species, we found support for the prediction that highly fragmented landscapes sustain genetically less diverse populations. We suggest, however, that future studies should focus on species of varying life-history traits inhabiting independent landscapes to better understand how habitat fragmentation influences within-population genetic diversity.


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