Stem density and size stratification of woody species are informative of vegetation conditions and its physiognomy in savannah whereas their variation influence woody population functioning. Current study endeavoured ...Stem density and size stratification of woody species are informative of vegetation conditions and its physiognomy in savannah whereas their variation influence woody population functioning. Current study endeavoured to evaluate the stand density and size variability of woody species related to aboveground biomass in a Sudanian savannah. Total height, stem diameter at breast height (dbh) ≥ 5 cm were measured in 30 plots of 50 m </span></span><span><span><span style="font-family:"">×<span> 20 m laid in respect to vegetation type as bowal, shrubland and woodland. Species diversity, stem density, height and basal area were calculated and compared across sites and variation in stem dbh classes evaluated. Total aboveground biomass was estimated and thereafter linear relationships were established between stand density and aboveground biomass</span></span></span></span><span><span><span style="font-family:"">,</span></span></span><span><span><span style="font-family:""> and basal area. Results revealed three different sites with an overall 58 species identified through vegetation type including liana species (4 stems in bowal) with 18 genera and 42 families. Fabaceae Combretaceae, Anacardiaceae and Rubiaceae were dominant families. Small sized trees represented 72% of total stem density considered in structure with significant higher basal area, while large sized trees as 28% were scarcely distributed. More than 70% variation in biomass w</span></span></span><span><span><span style="font-family:"">as </span></span></span><span><span><span style="font-family:"">due to stem density and basal area with a dominance of small trees. In conclusion increase size in tree community indicated increase in accumulated aboveground biomass as positive regeneration features. But, change in vegetation structure strongly influence negatively species ability to grow from lower to upper size class and later on, disrupt ecosystem functioning. Plant stem density and stratification could be considered as indicators of aboveground biomass 展开更多
The diversity, abundance and height structure of naturally regenerated woody species were analyzed and compared for undergrowth reservoir associated with vegetation patches as bowal, shrubland and woodland for underst...The diversity, abundance and height structure of naturally regenerated woody species were analyzed and compared for undergrowth reservoir associated with vegetation patches as bowal, shrubland and woodland for understanding the effect of vegetation conditions on spatial distribution of woody plants in Sudanian ecosystem. All undergrowth individuals (height < 1.5 m) were recorded by species and the total height and collar diameter were measured in 50 subplots of 5 m × 5 m (or 25 m<sup>2</sup>) laid out in each vegetation patch during rainy season. In total 52 undergrowth species and 2224 stems arranged in 38 genera and 21 families out of which 25, 36 and 38 species were found in bowal, shrubland and woodland respectively and 15 shared species. Combretaceae, Caesalpiniaceae and Mimosaceae families were the most abundant and species density was significantly higher (P < 0.05) in shrubland and woodland than bowal, and increase diversity in only shrubland (P = 0.002) comparing with bowal. Undergrowth was abundantly concentrated in small height class as canopy benefit and indicate a specific-site distribution. Results also showed that bowal had a particular vegetation which vary in function of tree community characters in place (P < 0.05) while woodland and shrubland are similar vegetation patches. As conclusion, the study vegetation patches form suitable regeneration niches for the undergrowth reservoir of limited number of species which in return can be predictor of species richness and abundance and thus the structure of tree community. Woody undergrowth community could be considered in biodiversity management and degraded land restoration. Supplementary works could be undertaken to understand the characteristics of seed bank for bowal, shrubland and woodland regarding the undergrowth and tree communities.展开更多
文摘Stem density and size stratification of woody species are informative of vegetation conditions and its physiognomy in savannah whereas their variation influence woody population functioning. Current study endeavoured to evaluate the stand density and size variability of woody species related to aboveground biomass in a Sudanian savannah. Total height, stem diameter at breast height (dbh) ≥ 5 cm were measured in 30 plots of 50 m </span></span><span><span><span style="font-family:"">×<span> 20 m laid in respect to vegetation type as bowal, shrubland and woodland. Species diversity, stem density, height and basal area were calculated and compared across sites and variation in stem dbh classes evaluated. Total aboveground biomass was estimated and thereafter linear relationships were established between stand density and aboveground biomass</span></span></span></span><span><span><span style="font-family:"">,</span></span></span><span><span><span style="font-family:""> and basal area. Results revealed three different sites with an overall 58 species identified through vegetation type including liana species (4 stems in bowal) with 18 genera and 42 families. Fabaceae Combretaceae, Anacardiaceae and Rubiaceae were dominant families. Small sized trees represented 72% of total stem density considered in structure with significant higher basal area, while large sized trees as 28% were scarcely distributed. More than 70% variation in biomass w</span></span></span><span><span><span style="font-family:"">as </span></span></span><span><span><span style="font-family:"">due to stem density and basal area with a dominance of small trees. In conclusion increase size in tree community indicated increase in accumulated aboveground biomass as positive regeneration features. But, change in vegetation structure strongly influence negatively species ability to grow from lower to upper size class and later on, disrupt ecosystem functioning. Plant stem density and stratification could be considered as indicators of aboveground biomass
文摘The diversity, abundance and height structure of naturally regenerated woody species were analyzed and compared for undergrowth reservoir associated with vegetation patches as bowal, shrubland and woodland for understanding the effect of vegetation conditions on spatial distribution of woody plants in Sudanian ecosystem. All undergrowth individuals (height < 1.5 m) were recorded by species and the total height and collar diameter were measured in 50 subplots of 5 m × 5 m (or 25 m<sup>2</sup>) laid out in each vegetation patch during rainy season. In total 52 undergrowth species and 2224 stems arranged in 38 genera and 21 families out of which 25, 36 and 38 species were found in bowal, shrubland and woodland respectively and 15 shared species. Combretaceae, Caesalpiniaceae and Mimosaceae families were the most abundant and species density was significantly higher (P < 0.05) in shrubland and woodland than bowal, and increase diversity in only shrubland (P = 0.002) comparing with bowal. Undergrowth was abundantly concentrated in small height class as canopy benefit and indicate a specific-site distribution. Results also showed that bowal had a particular vegetation which vary in function of tree community characters in place (P < 0.05) while woodland and shrubland are similar vegetation patches. As conclusion, the study vegetation patches form suitable regeneration niches for the undergrowth reservoir of limited number of species which in return can be predictor of species richness and abundance and thus the structure of tree community. Woody undergrowth community could be considered in biodiversity management and degraded land restoration. Supplementary works could be undertaken to understand the characteristics of seed bank for bowal, shrubland and woodland regarding the undergrowth and tree communities.
