Effects of individual fire events on the flower production of fruit-bearing tree species, with reference to Aboriginal people's management and use, at Kalumburu, North Kimberley, Australia

2004 ◽  
Vol 52 (3) ◽  
pp. 405 ◽  
Author(s):  
T. Vigilante ◽  
D. M. J. S. Bowman

This study used a number of landscape-scale natural experiments to investigate the influence of individual fire events on the reproductive output of key fruit-bearing woody species [Buchanania obovata Engl. (two leaf forms), Persoonia falcata R.Br., Planchonia careya (F.Muell.) Knuth, Syzygium eucalyptoides (F.Muell.) B.Hyland, Syzygium suborbiculare (Benth.) T.Hartley & Perry. and Terminalia cunninghamii C.Gardner] around Kalumburu, North Kimberley, Australia. Flowering level was used as an estimate of reproductive success as sampling was done prior to fruit development.Terminalia cunninghamii was found to flower earlier and more prolifically in areas burnt in the early dry season of 1999 than in areas left unburnt; however, there was no significant difference between these treatments in 2000. Flowering levels were significantly reduced in burnt treatments (from early to mid-dry season fires) for Buchanania obovata (large-leafed form), Persoonia falcata, Planchonia careya, Syzygium eucalyptoides and Syzygium suborbiculare. Positive correlations occurred between the minimum foliage height and total tree height of Buchanania obovata small-leafed form (r = 0.78, y = 0.61x + 0.003), large-leafed form (r = 0.87, y = 0.59x + 0.10) and Syzygium suborbiculare (r = 0.76, y = 0.43x + 0.54). Above a height of 2 m, most trees have the majority of their foliage located in the top half of the tree. In all cases, flowering levels increased with foliage height intervals.The results indicate that fire events and their timing can have an impact on the reproductive cycle of fruit-tree species. Indigenous people have managed these resources through the careful use of fire. The conservation of fruit-tree species and frugivorous-animal species could benefit from (i) the careful management of areas with high densities of fruit-bearing species, and (ii) spatially and temporally diverse fire regimes across broader landscape units.

2019 ◽  
Vol 68 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Xiyang Zhao ◽  
Yanyan Pan ◽  
Xiaona Pei ◽  
Fuwei Wang ◽  
Chenglu Wang ◽  
...  

Abstract Tree height and diameter at breast height of 30 half-sib Larix kaempferi families were analyzed at different ages. Analysis of variance revealed a significant difference in growth among dif­ferent families. Phenotypic variation coefficients of the traits tree height and diameter at breast height among families of different ages ranged from 11.04 % to 31.74 % and 19.01 % to 19.83 %, respectively. Average heritability of tree height and diameter at breast height ranged from 0.87 to 0.96 and 0.93 to 0.96, respectively. Significant positive correlations were obser­ved among all traits at different ages. By the method of multip­le-traits comprehensive, six families (L18, L12, L8, L3, L25 and L20) were selected as being elite using a 20 % selection ratio at 12 years of age. Average values of these elite families were 11.15 % and 16.83 % higher than the total average for height and diameter at breast height, and genetic gains were 10.53 % and 15.79 %, respectively. Forty five elite individual plants were selected using a 5 % selection ratio which were 23.47 % and 24.90 % higher than the overall average for height and diame­ter at breast height, respectively.


Author(s):  
Mahtot Alemu Biresaw ◽  
J. Pavliš

This study was conducted in Jawi and East Belesa districts of the Amhara National Regional State in Ethiopia. It has an objective of describing the vegetation structure in relation to different environmental factors in general and Boswellia papyrifera, which is economically important species in particular. Vegetation data were collected in both sites (Mosebit and Hamusit) using plots of 50 m x 50 m (0.25 ha). In total 15 sample plots were set up. In each plot, all trees with DBH (Diameter at Breast Height), i.e. at 1.3 m above the ground were measured using caliper. In each major plot four subplots (4 m × 4 m) were established. Tree height measured using Hypsometer (Vertex III). Data’s on different environmental variables (slope, aspect and altitude) of each plot were also taken respectively using laser rangefinder Impulse 200 Standard, an electronic compass Map-Star Module II and GPS Juno™ ST handheld (Trimble, USA). A total of 58 woody species belonging to 22 families were identified from both sites. A total of 241 trees/ha and 292 trees/ha were found in Mosebit and Hamusit study sites, respectively. The seedling density result indicates 3656 seedlings/ha and 2469 seedlings/ha in Mosebit and Hamusit study areas, respectively. The density of Boswellia Papyrifera, which is economically important species were 140 and 127 tree/ha in Mosebit, and Hamusit study areas, respectively. The relative density of different tree species in different height and diameter classes were determined by altitude, aspect, and gradient of the study areas. The study result concludes that distribution of the species, relative density, height class and diameter class of species in the two sites is dependent on environmental factors. Finally, the findings indicate that the two woodlands harbor, economically important tree species. Therefore, giving due attention in conserving these wood lands is important from ecological, economical and conservation point of view.


2001 ◽  
Vol 10 (1) ◽  
pp. 79 ◽  
Author(s):  
A. Edwards ◽  
P. Hauser ◽  
M. Anderson ◽  
J. McCartney ◽  
M. Armstrong ◽  
...  

Fires burn vast areas of the monsoonal savannas of northern Australia each year. This paper describes the contemporary fire regimes of two ecologically similar, relatively large national parks (Litchfield—1464 km2; Nitmiluk—2924 km2) in the Top End of the Northern Territory, over 8 and 9 years, respectively. Fire histories for both parks were derived from interpretation of LANDSAT TM imagery, supplemented with NOAA-AVHRR for cloudy periods at the end of the 7-month dry season (c. April–Oct). Data concerning seasonality, extent and frequency of burning were analysed with respect to digital coverages for the park as a whole, landscape units, vegetation types, infrastructure and tenure boundaries. Ground-truth data established that interpreted accuracy overall, for 2 assessment years, ranged between 82 and 91% for both parks. Over 50% of Litchfield and 40% of Nitmiluk was burnt on average over this period, with Litchfield being burnt substantially in the earlier, cooler, and moister, dry season, and Nitmiluk mostly in the parched late dry season, after August. On both parks the current frequency of burning in at least low open woodland / heath habitats is ecologically unsustainable. Both parks are prone to extensive fire incursions. The data support earlier regional assessments that the average fire return interval is around 2 years in at least some areas of northern Australia. Nevertheless, comparison of contemporary fire regimes operating in three major regional national parks shows distinct differences, particularly with respect to the extent and seasonality (hence intensity) of burning in relation to different landscape components. Management implications are considered in discussion.


Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 129 ◽  
Author(s):  
Callie Oldfield ◽  
Chris Peterson

Salvage logging after wind disturbance of a mixed conifer-hardwood forest results in sapling compositional changes but no changes to species diversity six years post-disturbance. Several conceptual frameworks allow for predictions of the effects of forest disturbances on composition, but fewer yield predictions of species diversity. Following compound disturbance, tree species diversity and composition is predicted to shift to early successional species. Because of the greater cumulative severity, diversity should be lower in areas experiencing windthrow + salvage logging than in similar sites experiencing windthrow alone. We examined the effects of wind disturbance and salvage logging on diversity parameters over six years. We hypothesized that the effects of salvage logging on diversity would be short-lived, but that species composition would be altered six years post-disturbance. Sampling plots were established in a mixed-hardwood forest in north Georgia, USA, after a 2011 EF3 tornado and surveyed in 2012 and 2017. Nineteen 20 × 20 m plots were surveyed (10 unsalvaged, 9 salvaged) for parameters including Shannon diversity, species richness, and composition. Ordinations were used to visualize tree and sapling species composition in salvage logged plots. We found that there was no significant difference in Shannon diversity between salvaged and unsalvaged plots before disturbance, <1 post-disturbance, or 6 years post-disturbance. The disturbances altered the tree and sapling species compositions, with salvaged plots having more mid-successional saplings but few true pioneer species. There appears to be an emerging pattern in the wind disturbance + salvaging literature which our study supports– salvaging does not affect tree species diversity but shifts species composition over time.


HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1247-1250 ◽  
Author(s):  
Mukadder Kayum ◽  
N. Kemal Koç ◽  
Veli-Matti Rokka

Laser flow cytometry was used to analyze nuclear DNA contents (2C values) of five genera (Severinia Ten., Atalantia Corrèa, Fortunella Swing., Poncirus Raf., and Citrus L.) taxonomically grouped in subtribe Citrinae (citrus fruit trees) of the Rutaceae. The genotypes analyzed had 2C values ranging from 0.67 pg for diploid Severinia buxifolia (Poir.) Ten. to 1.27 pg for tetraploid Hongkong Fortunella hindsii Swing. There was no significant difference in the 2C values within the sexually compatible diploid species of 11 “true citrus fruit trees” [Citrus aurantium L., C. grandis (L.) Osbeck, C. limon (L.) Burm. f., C. limonia Osbeck, C. paradisi Macf., C. reshni Hort. ex Tanaka, C. sinensis (L.) Osbeck, C. volkameriana Ten. & Pasq., Poncirus trifoliata (L.) Raf., and the intergeneric hybrid C. sinensis × P. trifoliata]. The species Atalantia ceylanica (Arn.) Oliv. (a “near-citrus fruit tree”), sexually incompatible with Citrus spp., had a 2C value significantly different from those of the true citrus fruit tree species. The 2C value of Severinia buxifolia (a “primitive citrus fruit tree”), another species sexually incompatible with the Citrus spp., also differed from those of some of the true citrus fruit tree species. The data largely corresponds with taxonomical differences between a) the genera Citrus and Poncirus and b) the genera Severinia and Atalantia, all assigned to subtribe Citrinae.


BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Bertrand Andriatsitohaina ◽  
Daniel Romero-Mujalli ◽  
Malcolm S. Ramsay ◽  
Frederik Kiene ◽  
Solofonirina Rasoloharijaona ◽  
...  

Abstract Background Edge effects can influence species composition and community structure as a result of changes in microenvironment and edaphic variables. We investigated effects of habitat edges on vegetation structure, abundance and body mass of one vulnerable Microcebus species in northwestern Madagascar. We trapped mouse lemurs along four 1000-m transects (total of 2424 trap nights) that ran perpendicular to the forest edge. We installed 16 pairs of 20 m2 vegetation plots along each transect and measured nine vegetation parameters. To determine the responses of the vegetation and animals to an increasing distance to the edge, we tested the fit of four alternative mathematical functions (linear, power, logistic and unimodal) to the data and derived the depth of edge influence (DEI) for all parameters. Results Logistic and unimodal functions best explained edge responses of vegetation parameters, and the logistic function performed best for abundance and body mass of M. ravelobensis. The DEI varied between 50 m (no. of seedlings, no. of liana, dbh of large trees [dbh ≥ 10 cm]) and 460 m (tree height of large trees) for the vegetation parameters, whereas it was 340 m for M. ravelobensis abundance and 390 m for body mass, corresponding best to the DEI of small tree [dbh < 10 cm] density (360 m). Small trees were significantly taller and the density of seedlings was higher in the interior than in the edge habitat. However, there was no significant difference in M. ravelobensis abundance and body mass between interior and edge habitats, suggesting that M. ravelobensis did not show a strong edge response in the study region. Finally, regression analyses revealed three negative (species abundance and three vegetation parameters) and two positive relationships (body mass and two vegetation parameters), suggesting an impact of vegetation structure on M. ravelobensis which may be partly independent of edge effects. Conclusions A comparison of our results with previous findings reveals that edge effects are variable in space in a small nocturnal primate from Madagascar. Such an ecological plasticity could be extremely relevant for mitigating species responses to habitat loss and anthropogenic disturbances.


Author(s):  
Jayesh Anerao ◽  
Vikas Jha ◽  
Nishaat Shaikh ◽  
Apurva Shivalkar ◽  
Aishwarya Nityanand ◽  
...  

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie

Abstract Background Fire is an important process that shapes the structure and functioning of African savanna ecosystems, and managers of savanna protected areas use fire to achieve ecosystem goals. Developing appropriate fire management policies should be based on an understanding of the determinants, features, and effects of prevailing fire regimes, but this information is rarely available. In this study, we report on the use of remote sensing to develop a spatially explicit dataset on past fire regimes in Majete Wildlife Reserve, Malawi, between 2001 and 2019. Moderate Resolution Imaging Spectroradiometer (MODIS) images were used to evaluate the recent fire regime for two distinct vegetation types in Majete Wildlife Reserve, namely savanna and miombo. Additionally, a comparison was made between MODIS and Visible Infrared Imager Radiometer Suite (VIIRS) images by separately evaluating selected aspects of the fire regime between 2012 and 2019. Results Mean fire return intervals were four and six years for miombo and savanna vegetation, respectively, but the distribution of fire return intervals was skewed, with a large proportion of the area burning annually or biennially, and a smaller proportion experiencing much longer fire return intervals. Variation in inter-annual rainfall also resulted in longer fire return intervals during cycles of below-average rainfall. Fires were concentrated in the hot-dry season despite a management intent to restrict burning to the cool-dry season. Mean fire intensities were generally low, but many individual fires had intensities of 14 to 18 times higher than the mean, especially in the hot-dry season. The VIIRS sensors detected many fires that were overlooked by the MODIS sensors, as images were collected at a finer scale. Conclusions Remote sensing has provided a useful basis for reconstructing the recent fire regime of Majete Wildlife Reserve, and has highlighted a current mismatch between intended fire management goals and actual trends. Managers should re-evaluate fire policies based on our findings, setting clearly defined targets for the different vegetation types and introducing flexibility to accommodate natural variation in rainfall cycles. Local evidence of the links between fires and ecological outcomes will require further research to improve fire planning.


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