Piętra krajobrazowo-geochemiczne południowych stoków Kilimandżaro, Tanzania

The aim of this paper is to identify and describe the landscape and geochemical zones on the southern slopes of Kilimanjaro. Characterization of individual zones was carried out based on a literature synthesis and author own study. The article contains description of four main zones and eight subzones. The Kilimanjaro’s altitudinal vegetation zones have proper description, but this overview provides a holistic description of the structure and functioning of the landscape.

Riparian Vegetation Density Mapping of an Extremely Densely Vegetated Confined Floodplain

The most crucial function of lowland-confined floodplains with low slopes is to support flood conveyance and fasten floods; however, obstacles can hinder it. The management of riparian vegetation is often neglected, though woody species increase the vegetation roughness of floodplains and increase flood levels. The aims are (1) to determine the branch density of various riparian vegetation types in the flood conveyance zone up to the level of artificial levees (up to 5 m), and (2) to assess the spatial distribution of densely vegetated patches. Applying a decision tree and machine learning, six vegetation types were identified with an accuracy of 83%. The vegetation density was determined within each type by applying the normalized relative point density (NRD) method. Besides, vegetation density was calculated in each submerged vegetation zone (1–2 m, 2–3 m, etc.). Thus, the obstacles for floods with various frequencies were mapped. In the study area, young poplar plantations offer the most favorable flood conveyance conditions, whereas invasive Amorpha thickets and the dense stands of native willow forests provide the worst conditions for flood conveyance. Dense and very dense vegetation patches are common in all submerged vegetation zones; thus, vegetation could heavily influence floods.

Salt marsh width positively affects the occurrence of Least and Pectoral Sandpipers in the St. Lawrence River Estuary during fall migration

Salt marshes are vulnerable to climate change-associated sea-level rise and storm-induced surges. Their degradation will likely affect shorebirds relying on this ecosystem. Least Sandpiper (Calidris minutilla) and Pectoral Sandpiper (Calidris melanotos) migrating along coastline habitats typically use salt marshes to rest and replenish their body reserves. Our objective was to test if width of the different vegetation zones within salt marshes affects the occurrence of Least and Pectoral Sandpipers stopping along the St. Lawrence River Estuary, Quebec, Canada, during fall migration. We established 26 survey sites, each 600 m in length, along the shoreline. Shorebird surveys were conducted in 2011 and 2012. We characterized salt marshes by measuring the width of each vegetation zone (lower marsh and upper marsh). We analyzed shorebird presence/not detected data with generalized estimating equations to test the predictions that occurrence of Least Sandpipers and Pectoral Sandpipers increases with width of both the lower and upper marsh. Upper marsh width was positively associated with probability of occurrence in each species. Our results highlight the importance of protecting the integrity of salt marshes for these two species. In the St. Lawrence River Estuary, where landward migration of salt marshes is no longer possible (coastal squeeze), effective management of shorelines is much needed. Otherwise, salt marshes and these two species could be locally jeopardized.

Effect of vegetation distribution driven by hydrological fluctuation on sedimental stoichiometry regulating N₂O emissions in freshwater wetland

Hydrological conditions drive the distribution of plant communities in wetlands to form vegetation zones where the material cycling varies with plant species. This mediation effect caused by the distribution of vegetation under hydrological conditions will affect the emission of N2O during the nitrogen migration in wetlands. In this study, five vegetation zones in the second largest wetland of China were investigated in situ during high and low water levels to elucidate the effect mediated by vegetation. With the increase in the rate of change of water levels, the zones of the mud flat, nymphoides, phalaris, carex, and reeds were distributed in sequence in the wetland, and the densities of carbon and nitrogen sequestrated by plants also increased. The carbon and nitrogen densities in each zone during low water level was significantly higher than that during high water level, while the organic carbon and the total nitrogen of sediments during high water level was higher. Sediments converted between source and sink for both carbon and nitrogen, during the annual fluctuation in water level. The flux in N2O emissions showed significant differences between the vegetation zones during each water level period. The emission flux decreased with the increasing C : N ratio in sediments, approximating the threshold at 0.23 μg m−2 h−1 when the C : N ratio > 25. The phylum abundance of Firmicutes, Proteobacteria, and Chloroflexi in sediments increased with flooding. The denitrifying nirS and nirK genes and anammox hzsB gene were significantly affected by water level fluctuation, with the maximal variations of these genes occurring in the mud flat and nymphoides zone. The results indicate that the distribution of plants under hydrological conditions modified the stoichiometric ratio of sediments, resulting in the variations of N2O emission fluxes and microbial communities in vegetation zones. Therefore, hydraulic regulation rather than direct planting would be an effective strategy to reduce greenhouse gas emissions in freshwater wetlands.

Migration and Climate Change Impacts on Rural Entrepreneurs in Nigeria: A Gender Perspective

Although the effects of climate change are universal, some groups are more negatively affected than others, which has raised global concerns. The most affected are families involved with agriculture or that use natural resources in rural areas as a means of livelihood. This study aimed to assess the responses of rural dwellers to climate change and migration, determine the extent of climate change as a driver of migration, assess the viability of migration as an option for climate change adaptation, and evaluate the gender perspective of migration and the impact of climate change on entrepreneurial development in rural areas. A qualitative method was employed to solicit responses from respondents in selected rural areas under four different vegetation zones through in-depth interviews and focus group discussions. Data were analyzed using Atlas.ti. A difference was found in gender reactions to migration due to socio-cultural factors and family responsibilities. In addition, different types of migration patterns were found to exist among men and women. The study also revealed that climate change is a major driver of migration, affects livelihood practices differently in the vegetation zones, and has a negative impact on the entrepreneurship development of the rural areas. Finally, this study provides insights into the effect of migration type on the entrepreneurship development by gender.

Evaporation, infiltration and storage of soil water in different vegetation zones in Qilian mountains: From an perspective of stable isotopes

In arid areas, almost all the water resources in the basin come from mountainous areas. Nvertheless, the process of water storage and runoff generation has not been fully understood in different vegetation zones in mountainous areas, which is the main obstacle blocking human cognition of hydrological processes and water resources assessment. In current study, the spatiotemporal dynamics of stable isotopes were monitored in different water bodies and soil water storage in different vegetation zones in the upper reaches of Xiying River. The results show that: (1) The water storage capacity of surface soil was weak in vegetation zones, and soil water was mainly saved up in the middle and lower soil layers. (2) Surface and subsurface runoff could form in the Alpine Meadow and Coniferous Forest during the rainy season and the snow melting season. The lower elevation vegetation zones of Mountain Grassland and Deciduous forest evaporate strongly and infiltrate partially into the middle and bottom layers of the soil to store or recharge groundwater, rarely generating surface runoff. This work would provide a scientific foundation for reasonably explaining the mechanism of water production in mountainous areas of arid regions, and provide a reference for formulating management policies suitable for sustainable development of water resources and improving the ability to cope with climate change in arid areas.

Difference of SPAC composition and control factors of different vegetation zones in north slope of Qilian Mountains

Understanding the differences and controlling factors of stable water isotopes in the soil-plant-atmosphere continuum of different vegetation zones has important guiding significance for revealing the hydrological processes and regional water cycle mechanisms.This study selected three different vegetation zones (alpine meadows, forests, and arid piedmont zones) in the Shiyang River Basin for study. This paper’s analysis results show that: (1) In SPAC, precipitation isotope has the main controlling effect. From alpine meadows to arid foothills, as the altitude decreases, the temperature effect of precipitation isotopes increases. (2) From the alpine meadow to the arid foothills, the soil water isotope is gradually enriched, indicating that the evaporation is gradually increasing. (3) Alpine meadow plants are mainly supplied by precipitation in the rainy season; forest plants mainly utilize soil water in the dry season and precipitation in the rainy season. The soil water in the arid mountain foothills is mainly recharged by groundwater, and the evaporation and fractionation of plant isotopes are very strong.This research will help understand the SPAC system’s water cycle at different altitudes and climates on high mountains.

Building Today’s World

Once they were equipped with the social tools that allowed them to maintain greater connectedness, there was no looking back for our ancestors. They evolved much more complex cultures. Once the planet started to warm up and ice started to melt, humans could start to inhabit more of the land surface. As climate variability diminished and stable vegetation zones and habitats began to form, humans started to settle and become expert at exploiting a certain territory. If a group of families developed the knowledge and skills that allowed them to exploit a territory, there was no benefit in sharing that information with people outside the group. So instead of maintaining connections and sharing, people became tribal and, in many cases, territorial. Over thousands of years, families and tribes interacted and formed alliances, and their alliances broke down. But the general trend was for greater connectedness, increasingly complex cultures, and greater success. The human population grew.