Understanding about land cover and land use (LCLU) changes, as well as the associated impacts on ecosystem service values (ESV) is extremely important in the management of coastal ecosystems globally. Thus, this study assessed temporal LCLU changes, the underlying socioeconomic drivers and dynamics of ESV in the coastal zone of Tanzania.
In vitro pollen germination provides a novel approach and strategy to accelerate genetic improvement of tree breeding. Studies about pollen germination and tube growth of Chinese fir are limited. Therefore, this study aimed to investigate the effects of sucrose, boric acid, pH, and time of incubation on pollen germination and tube growth. Pollen from 9 clones were selected. In vitro germination was performed in basic media as control, and in different concentrations of sucrose (0, 10 and 15%), boric acid (0.01, 0.1 and 0.2%), and pH levels (4.5, 5 and 7). Pollen germination rates and tube growth were recorded periodically at 1, 12, 24, and 48 h. The results showed that sucrose imposes significant effects on pollen germination and tube growth. The effects are most obvious at concentration of 15%. Boric acid significantly promoted germination and tube growth. The promotion was most notable in lower concentration of 0.01%. The media adjusted to pH 7.0 boosted the germination and pollen tube growth. The optimum time of incubation was 24 and 48 h for pollen germination and tube growth, respectively. Sucrose, pH, and time of incubation were positively correlated, whereas boric acid negatively correlated with pollen germination and tube growth. This study provided experimental evidences for selecting viable pollens for Chinese fir breeding.
It is critical to understand how forests regenerate after the exclusion of human induced disturbances because the regenerating species drive the renewal of resources and ecosystems, which in turn support human beings locally and globally. This study of forest regeneration was conducted in the tropical coastal forest ecosystems of Tanzania at Uzigua Forest Reserve (24,730 ha) in the Pwani Region. We collected data from adult trees in 47 sampling plots (25 9 25 m) randomly established in closed forest sites (control) and in sites disturbed by farming and livestock grazing. Sapling and seedling data were collected and analyzed in 2 9 2 m nested subplots. Plots in the closed forest had higher mean basal area and volume for adult trees than those in sites disturbed by farming and livestock grazing. Plots in sites disturbed by farming had the highest Shannon-Wiener index for seedlings and saplings, followed by closed forest and livestock grazed sites. Closed plots and farmed plots had higher Simpson's index for seedlings and saplings than in grazed sites. Plots in farmed and livestock-grazed sites had a higher Simpson index for adult trees than in closed sites. Equitability of seedlings and saplings was highest in closed forest sites, followed by farmed and livestock grazed sites. Plots disturbed by farming had higher equitability for adult trees than in livestock-grazed and closed sites. Moreover, plots disturbed by farming and grazing had a higher importance value index for seedlings than in closed sites. Plots in closed forests had higher sapling importance values than in farmed and grazed sites. Again, plots in closed forest had a higher importance value for adult trees than in farmed and grazed sites. The differences in tree species subcategories of regeneration across land-use indicates that farming and livestock grazing disturbances create heterogeneous microhabitats, which positively or negatively affects regeneration capacity of species after exclusion.
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