Seedlings of V. Intraspecific and interspecific association - We found vegetation patches in the sample area. From this total, 30 patches had an area greater than 20 m 2 and were used to perform the association tests. The correlation matrix showed positive association between adults of C. Multiple regression analysis showed a marginal significant positive association between C. No association between juveniles was detected table 3.
CSIRO PUBLISHING | Australian Journal of Botany
Sexual vs. Clusia hilariana , Protium icicariba and Andira legalis showed this combination. However, their life strategies were clearly different: C. The relevance of vegetative propagation, via clonal growth andor resprouting, has often been demonstrated for the regeneration of restinga species Sampaio et al. The absence of young plants of A. Clusia hilariana , instead, showed a more conspicuous asexual production of plants, which may confer advantages to these regenerants such as physiological integration, i.
The suitability of bromeliad rosettes for seed germination and seedling establishment has been shown for strangling Clusia and Ficus species in rain forests Benzing , for Tabebuia tree species in a Brazilian swamp forest Scarano et al. This is the first time a comparative survey of plant occurrence inside and outside bromeliads has been conducted, and C. It remains to be seen whether these plants will reach the soil later on, to establish and grow until the reproductive phase. The larger proportion of juveniles than seedlings of C.
These results are in agreement with reproductive biology studies on this species by Faria et al. Protium icicariba , conversely, seemed to be actively regenerating as seen by the reversed-J curve of population size structure. Thus, the two dominant species of this vegetation show contrasting reproductive strategies. Plant-plant associations and succession - All significant associations found in this study were positive. This is in accordance with the reported prevalence of positive interactions between plants under harsh environmental conditions Callaway et al.
Clusia hilariana and P.
Thus, the positive association between adult individuals of C. This is further evidence that patches with C. This highlights the role of C. In conclusion, facilitation, as assessed here by plant-plant positive associations, appeared to be the predominant interaction among the species studied in this community, although it was clear that not all species studied were nurse plants and that nursing was rather selective.
Bromeliads played an important role in nursing C. This confirms the first and second expectations of this paper.
Age, stage and senescence in plants
Protium icicariba , despite showing a mutual positive association with C. It is noteworthy that vegetative propagation, unlike our third expectation, was not as relevant to the study species as previously reported in other studies. Vernonia crotonoides and A.
- Age, stage and senescence in plants;
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Thus, it seems that succession leading to an increase in complexity in the restinga , i. Acknowledgements - We thank D. Araujo for comments on the manuscript and methodological, taxonomic and linguistic advice; G.
Ganade, V. Nascimento and R.
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Iglesias Rios for comments on the manuscript; B. Aglai, P. Cirne, R. Montezuma, D. Santos and H. Zaluar for field assistance; J. Valentin and M. Garbin for statistical advice; C. Reproductive strategies in dewberries. Ecology Demography and vegetative reproduction. In Demography and evolution in plant populations O. Solbrig, ed. Blackwell, Oxford, p. Comunidades vegetais do Parque Nacional da Restinga de Jurubatiba. Esteves, ed. Comparative biology of neotropical epiphytic and saxicolous Tillandsia species: population structure. Journal of Tropical Ecology Vascular epiphytes.
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Facilitation in plant communities: the past, the present, and the future. Journal of Ecology Inclusion of facilitation into ecological theory. Trends in Ecology and Evolution Positive interactions among alpine plants increase with stress. Nature Resprouting and growth dynamics after fire of the clonal shrub Andira legalis Leguminosae in a sandy coastal plain in southeastern Brazil. Plant diversity, interspecific associations and postfire resprouting on a sandy spit in a Brazilian coastal plain.
Ecotropica DIAS, A. Clusia as nurse plant. In Clusia - a woody neotropical genus with remarkable plasticity and diversity U. In past, both the parks were included within a continuous Sal Shorea robusta belt and consisted of same species composition Alam With the increasing population both park areas are facing tremendous human pressures.
nn.threadsol.com/189232-cell-surveillance.php The diversities of these ecosystems are unknown to the outsiders and not well documented. On the other hand, there is no information whether the species composition and diversity of both parks are remaining on a comparable level like in the past or the parks show a different picture today. There are many studies on vegetation analysis of the Sal forests of Nepal and India Murali et al. A large-scale inventory about the plant diversity of Sal forests in Bangladesh is currently lacking.
However, very few research activities focusing on the enlisting of the available plant species in the Sal forests of Bangladesh are available Alam , Choudhury , Jashimuddin et al. It is essential to know the plant diversities of these ecosystems to understand the diversity of these ecosystems comparing the status and diversity of Sal forests of other countries like India and Nepal. The main objectives of this contribution is to know the species richness and community structure of the highly protected core zones of the Madhupur and Bhawal National Park and to compare the vegetation composition between these two parks.
Materials and Methods Study areas The study was carried out in the core zone of two Sal dominating national parks of Bangladesh: Madhupur and Bhawal National park Figure 1. The forests are fragmented by an intricate network of depressions in a honeycomb pattern layout. The depressions are generally cultivated with paddy. Homesteads, cultivable land, and forests are mixed. Both the parks belong to the bio-ecological zone of Madhupur Sal Tract Nishat et al.
This tract represents highly oxidized reddish brown clay containing ferruginous nodules and manganese spots. According to Richards and Hassan , the soils have a moderate to strong acidic reaction. The topography of both parks is characterized by plain land or low hills rising 3. A total of plots from the core zone of the Madhupur National Park and plots from the Bhawal National Park were taken on transects with a minimum distance of m from plot to plot, in most cases.
The starting point of each transect walk in whole study area was fixed on the road at m distance from the last intersection of two roads. Due to the presence of depressions in the landscape, forest gaps, or bare land, it was not always possible to establish the plots in a regular distance.
The plots on the transect were examined continuously at m distance in areas with a more or less closed forest cover, but in cases of fragmentations the next plot was taken at m or m distance. Results Comparing species richness A total number of species were recorded in the core zone of Madhupur National Park from which 65 were represented by tree species, 15 by shrub species, 26 by climbers and 23 by herbs. The Bhawal National Park inventory yielded a total of 43 plant species, out of which 22 were represented in the tree group, 10 in the shrubs group, 6 in the climbers group and 5 in the herbs group.
The regeneration categories on the basis of the proportion of saplings, large seedlings and small seedlings are comparable between both parks Table 4. Clerodendrum serratum was also the dominant species in the Bhawal National Park followed by Randia dumetorum, Dalbergia spinose and Ageratum sp. Mikania micrantha was the dominant species of the climbers followed by Smilax macrophylla, Scindapsus officinalis and Calamus tenuis.
In the Bhawal National Park, Pothos scandens was the dominant climber species followed by Smilax macrophylla and unknown species local name: Nangollata. Ageratum conyzoides was the dominant herb species followed by Imperata cylindrical and Oplismenus aemulus in the Madhupur National Park.
No coarse woody was found in the Bhawal National Park. Only very few number of standing coarse woody debris 2. Lying coarse woody debris or logs was absent. Diameter and height class distributions The diameter distributions based on the sampled trees of the individual plots of all forest types followed a reverse J-shaped distribution in both Madhupur and Bhawal National Park. With an increase of the diameters at breast height DBH the relative abundance of tree decreased.
Furthermore, a synoptic vegetation table was generated to identify specific species or species groups that were positively or negatively associated with the different population types. A subjective correction was performed on a few samples Wageningse waard, Randerwaard. Classification of these populations was difficult due to the small number of individuals.