Tropical Ecology最新文献

The internal retranslocation of nutrients of senescence leaves is a significant aspect of nutrient dynamics in a forest ecosystems. The present investigation was carried out by considering four types of deciduous tree species (Shorea robusta, Tectona grandis, Schleichera oleosa, and Albizia lebbeck) to assess nutrient resorption efficiency (NuRE) and resorption proficiency (NuRP) of nitrogen (N), phosphorous (P), and potassium (K), as well as seasonal changes of nutrient concentration in green and senescence leaves. Green and senescent leaves were sampled and analysed for NPK concentration by standard methods. Experimental results revealed that the higher nutrition contents were recorded in green leaves than senescence leaves. The highest N and P resorption efficiency (RE) were recorded for S. robusta and lowest for T. grandis (46.74%) and A. lebbeck (37.93%) respectively, whereas T. grandis exhibited the highest resorption efficiency of K (47.67%) and lowest for A. lebbeck (40.29%). Furthermore, the highest percentage of nutrients from mature leaves and soil were transported to the tree body during senescence were 47.0% (S. oleosa), and 21.29% (T. grandis), respectively. Moreover, nutrients were retranslocated from senescent leaves in the order as N > P > K. On the other hand, the nutrient resorption proficiency (NuRP) was highest with respect to N (53.26%) and P (62.07%) for T. grandis and K (59.71%) for A. lebbeck. Similarly, the lowest with respect to N (44.27%) and P (50.91%) for S. robusta, and K (52.33%) for T. grandis. Therefore, it can be concluded that changes in nutrient concentrations in green and senescence leaves could be the possible reason for different retranslocation efficiency.

Graphical abstract

The life history traits of the invasive slug, Deroceras laeve, occurring in the Darjeeling Himalayas, India, were estimated under laboratory conditions using the hatchlings from eggs of field-collected D. laeve. The growth pattern of D. laeve was found to be logarithmic, rapidly increased initially, and reached a stable condition till death. The maximum life span of D. laeve was 138 ± 3.48 days, with slightly higher mortality during the juvenile period, which decreased gradually at older ages. The pre-reproductive period of 37 ± 2.7 days, reproductive period of 100.8 ± 5.2 days, and 5.4 ± 1.72 days post-reproductive period of D. laeve were observed. D. laeve attained sexual maturity during 38 ± 2.7 days, and the age-specific fecundity increased with increasing age. The hatchability of the eggs was observed to be > 75% following the incubation period of 14.25 ± 0.49 days. The net reproductive value (R₀), generation time (T_c), and finite rate of increase (λ) were 40.01, 12.48 weeks, and 1.455, respectively. Apparently, the earlier sexual maturity, high net reproductive rate, and shorter generation time of D. laeve are indicative of its invasive nature as well as prospective range expansion in similar geographic locations.

In recent years, Hainan Eld’s deer (Cervus eldi) population in the Datian Nature Reserve (DNR) has been decreasing. This may be due to predation by Burmese python (Python bivittatus), as the number of Eld’s deer predation events by Burmese pythons has increased since 2013. This poses huge pressure on the DNR that is mainly involved in the conservation of wild Eld’s deer population. We divided the changes in deer population size in the DNR into three time periods (1988–1992, 1999–2003, and 2015–2019) according to changes in the number of Burmese pythons. We analyzed changes of Eld’s deer population in the Wenchang conservation station (WNR) for the period 2010–2018. In the DNR, Eld’s deer population increased from 242 to 349 during 1988–1992 in the absence of Burmese python. When there were few Burmese pythons in the region in 1999–2003, Eld’s deer population increased from 702 to 1075. In 2015–2019, when the number of migrating Burmese pythons captured was the greatest, Eld’s deer population decreased from 306 to 223, and the mean annual growth rate was − 6.21%. As predation by Burmese pythons decreases the survival rate of Eld’s deer fawns in the DNR, the growth rate of Eld’s deer population was significantly affected. Our results indicated that predation by Burmese python is currently a key factor affecting the growth of Eld’s deer population.

Coffee is a crucial crop for the economy of several countries. It contributes substantially to the livelihoods of millions of small producers worldwide. Coffea canephora represents 40% of the world's production of beans. Coffea canephora is a perennial crop, it is sensitive to climate, and several production areas in Brazil may become unfit for C. canephora cultivation due to expected climate change. Thus, knowledge of the temporal dynamics of favorable climate conditions for C. canephora in Brazil is necessary. This work aims to elaborate the CLIMEX model to predict the climatic suitability for C. canephora in Brazil in the current climate and front of climate changes for 2030, 2050, 2070, and 2100. The model shows a good agreement between the density and the growth rate of the species, which indicates significant reliability of the results in the proposed model. Our modeling results show that there has been a reduction in the areas very favorable to C. Canephora over the years, in the North, Southeast, and the entire east coast of the Northeast regions. Compared to the current scenario, the model projection reduces by 49, 73, 82, and 88% in 2030, 2050, 2070, and 2100, respectively. The results may help long-term planning strategies to mitigate the economic effects of the climate change scenario on C. canephora production in Brazil.

Graphical Abstract

Association of agriculture with climate change is widely established. Soil constituents and soil salinity along with the amendments for soil improvement are the key contributors in affecting this association. The present study targets the above issue to find the best management practice in terms of reduction in greenhouse gas (GHG) emissions in Indo-Gangetic plain of Uttar Pradesh. The six sites selected for the study varied in salinity level and followed different management practices of organic and inorganic amendments. Emissions of CO₂, CH₄ and N₂O from soil were measured at different stages of rice and wheat/ mustard/ fallow systems. The findings revealed that soil salinity, crop type and organic/ inorganic amendments differently affected the emission as the fluxes of GHGs varied at different stages of crop growth cycle at different sites. Salinity induced variations generally tended to reduce the CH₄ emission while increased the emission of CO₂ and N₂O, whereas organic matter amendment increased CO₂ and CH₄ fluxes in comparison to inorganic fertilizer application at the studied sites. The site with rice-mustard cropping exhibited the highest CO₂ and N₂O fluxes, measuring 3645 and 1.9 mg m^− 2 h^− 1, respectively. Conversely, the highest CH₄ flux of 0.873 mg m^− 2 h^− 1 was recorded at the saline rice-wheat cropping site. Electrical conductivity, moisture content, soil temperature and total organic carbon acted as major explanatory factors for soil emission of all the GHGs. Further exploration and experimentation are suggested with the use of different amendments to reduce GHG emissions in rice-wheat system, for greater sustainability potential. This ongoing research is vital for optimizing agricultural practices and enhancing their long-term environmental viability.

Floodplains have a high diversity of aquatic environments, including temporary lakes that constantly suffer from drought events. To survive in these conditions, several groups of organisms, among them ciliate protists, have developed strategies to avoid dehydration, such as resistance cysts. Sediment samples were collected from the central region of the lake during a drought event. The sediments were dried in an oven and stored. For the experiment, the sediment was rehydrated with water and kept in an incubation chamber. Samples from 6 microcosms were taken every seven days for 9 weeks. The frequency of each ciliate species hatching from resting structures was calculated using the constancy index, with morphospecies classified as constant, accessory, or rare. A total of 82 ciliates morphospecies were recorded, of which four were constant, three accessory, and 75 rare. The Oxytrichidae and Euplotidae families showed the highest morphospecies richness, among which only 16 morphospecies were already recorded in the literature as producing cysts. Although no significant temporal difference was observed for the difference in the hatching of morphospecies over time. The morphospecies increment curve showed an increasing trend during the experiment. Finally, based on predicted climate change projections, temporary environments may experience longer and more frequent periods of drought, thus ciliate morphospecies that are able to remain in a form of resistance for a long period will outperform those that are more sensitive or lack this type of functional trait.

The rapid expansion of agriculture in the Souss Massa region has been accompanied by a significant increase in pesticide usage to protect and increase crop yields. Unfortunately, these pesticides leave behind residues that can have detrimental effects on both human health and the environment. To investigate the impact of pesticide contamination on the coasts of Agadir Bay, our study focuses on the bivalve Perna perna (Linnaeus, 1758) as a biomonitoring sentinel species. Between autumn 2009 and summer 2010, we conducted measurements of pesticide residue concentrations and assessed two biomarkers of pollution the Glutathion-S-transferase (GST) and acetylcholinesterase (AChE) in the soft tissues of P. perna. These bivalves were seasonally collected from two different locations along the Agadir Bay coast. The results revealed that Glutathion-S-transferase and acetylcholinesterase showed seasonal variations, likely influenced by the species' reproductive cycle. In terms of pesticide concentrations, the levels of organochlorines were found to range from 13.40 to 109.76 ng g⁻¹ of dry weight (dw) for Dichlofluanide, not-detected (ND) to 38.66 ng g⁻¹ dw for Endosulfan S, ND to 15.76 ng g⁻¹ dw for Lindane, ND to 33.66 ng g⁻¹ dw for Fenarimol, and 0.26–35.02 ng g⁻¹ dw for Buperimate. It should be noted that these levels of pesticide contamination are relatively low compared to values reported in similar studies conducted in other regions of the world. The contamination of Agadir Bay by pesticides can be attributed to their extensive use in agricultural practices in the Souss Massa region.

With the rapid development of urbanization level, the continuous expansion of urban areas and unreasonable planning have taken place in the underlying surface of the city. River and lake water systems, wetlands and green land have been occupied, and the impervious area has increased, which has destroyed the hydrological cycle of the city, leading to a series of urban water problems. The construction of a sponge city is an important measure for similar problems. Aquatic plants are the most important part of water ecological restoration technology. Their developed roots can absorb nutrients in the water. Moreover, using aquatic plants as the main body of water for ecological restoration can not only control the eutrophication of water, but also have a good landscape effect, and will not cause secondary pollution. Therefore, the purpose of this paper is to explore the problem of improving the sponge city environment by aquatic plants based on ecological restoration theory and analyze the problems and solutions in the process of sponge city environmental protection construction. In this paper, the research method of specific analysis was used to compare the data to achieve a conclusion. The results showed that the development mode of sponge construction in practical cities will effectively reduce surface runoff by 15% and rainfall and flood by 21%. It can also solve the problems of urban waterlogging, water ecosystem restoration and heat island effect mitigation. Therefore, it was of great significance to study the ecological mode of rainwater utilization in the construction of a sponge city, analyze the collection ways and different application modes, to relieve the pressure of urban water resources and promote the efficient and comprehensive utilization of water resources in China.

The adaptation measures in the forestry sector are essential to mitigate climate change and to support sustainable development. Reducing emissions through improved forest management is a critical approach for climate change adaptation. Several previous investigations have estimated carbon stock for forest ecosystems. However, the drivers of this function are less understood, especially in the tropical context. Hence, this investigation intended to explore the factors affecting the carbon stock potential of dry Afromontane forest in southern Ethiopia. Employing a systematic sampling system, ten transects were laid out with 125-m intervals along the altitudinal gradient. The main plots (size 20 m × 20 m each and two subplots (each: 10 m × 10 m) were laid out in the opposite corner of the main plots and in total 46 main plots and 92 subplots were used for vegetation and dead wood data collection respectively. The plots were arranged on transects at 125 m interval to measure trees and shrubs, respectively. Moreover, a total of 230 sub-sub plots (1 m × 1 m) were arranged at the four corners and in the center of the main plots to collect herbs and litters for the assessment of non-woody carbon stocks. The altitude and topographic aspects of the sample plots were recorded using Garmin GPS and Silva compass, respectively. The carbon stock was calculated using allometric equations developed for the estimation of dry Afromontane forest carbon stocks. The effect of species type, altitude, and topographic aspects on above-ground and below-ground carbon stock was analyzed by using one-way ANOVA. The results revealed that the total above-ground and belowground carbon stock of dry Afromontane forest is 1943.2 tons/ha. The carbon stock of woody species stock increased with increasing altitudinal gradient but opposite trend was found for non-woody species. Moreover, the carbon stock of both woody and non-woody species significantly varied among topographic aspects and plant family types. The carbon stock was higher for Cupressaceae (811.5 tons/ha) followed by Podocarpaceae (630.9 tons/ha). The highest carbon stock of woody biomass was recorded in the southwest aspect (663.30 tones/ha), and the lowest carbon (141.8 tons/ha) was recorded in the northwest topographic aspect. In conclusion, the environmental and vegetation structure need to be considered in devising forest conservation strategy for climate change mitigation and adaptation.