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1
Leach, Melissa, Bernard Bett, M. Said, Salome Bukachi, Rosemary Sang, Neil Anderson, Noreen Machila, et al. "Local disease–ecosystem–livelihood dynamics: reflections from comparative case studies in Africa." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1725 (June 5, 2017): 20160163. http://dx.doi.org/10.1098/rstb.2016.0163.
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This article explores the implications for human health of local interactions between disease, ecosystems and livelihoods. Five interdisciplinary case studies addressed zoonotic diseases in African settings: Rift Valley fever (RVF) in Kenya, human African trypanosomiasis in Zambia and Zimbabwe, Lassa fever in Sierra Leone and henipaviruses in Ghana. Each explored how ecological changes and human–ecosystem interactions affect pathogen dynamics and hence the likelihood of zoonotic spillover and transmission, and how socially differentiated peoples’ interactions with ecosystems and animals affect their exposure to disease. Cross-case analysis highlights how these dynamics vary by ecosystem type, across a range from humid forest to semi-arid savannah; the significance of interacting temporal and spatial scales; and the importance of mosaic and patch dynamics. Ecosystem interactions and services central to different people's livelihoods and well-being include pastoralism and agro-pastoralism, commercial and subsistence crop farming, hunting, collecting food, fuelwood and medicines, and cultural practices. There are synergies, but also tensions and trade-offs, between ecosystem changes that benefit livelihoods and affect disease. Understanding these can inform ‘One Health’ approaches towards managing ecosystems in ways that reduce disease risks and burdens. This article is part of the themed issue ‘One Health for a changing world: zoonoses, ecosystems and human well-being’.
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Bond, William J., and Guy F. Midgley. "Carbon dioxide and the uneasy interactions of trees and savannah grasses." Philosophical Transactions of the Royal Society B: Biological Sciences 367, no. 1588 (February 19, 2012): 601–12. http://dx.doi.org/10.1098/rstb.2011.0182.
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Savannahs are a mixture of trees and grasses often occurring as alternate states to closed forests. Savannah fires are frequent where grass productivity is high in the wet season. Fires help maintain grassy vegetation where the climate is suitable for woodlands or forests. Saplings in savannahs are particularly vulnerable to topkill of above-ground biomass. Larger trees are more fire-resistant and suffer little damage when burnt. Recruitment to large mature tree size classes depends on sapling growth rates to fire-resistant sizes and the time between fires. Carbon dioxide (CO 2 ) can influence the growth rate of juvenile plants, thereby affecting tree recruitment and the conversion of open savannahs to woodlands. Trees have increased in many savannahs throughout the world, whereas some humid savannahs are being invaded by forests. CO 2 has been implicated in this woody increase but attribution to global drivers has been controversial where changes in grazing and fire have also occurred. We report on diverse tests of the magnitude of CO 2 effects on both ancient and modern ecosystems with a particular focus on African savannahs. Large increases in trees of mesic savannahs in the region cannot easily be explained by land use change but are consistent with experimental and simulation studies of CO 2 effects. Changes in arid savannahs seem less obviously linked to CO 2 effects and may be driven more by overgrazing. Large-scale shifts in the tree–grass balance in the past and the future need to be better understood. They not only have major impacts on the ecology of grassy ecosystems but also on Earth–atmosphere linkages and the global carbon cycle in ways that are still being discovered.
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Madjima, Soro Nounfro, Ehouman N’guetta Moïse, Toure Mamadou, Ouattara Noufou Doudjo, and Tiho Seydou. "Diversité Et Dynamique Des Communautés De Vers De Terre De Trois Formations Végétales Dans Une Savane Humide De l’Afrique De l’Ouest (Lamto, Côte d’Ivoire)." European Scientific Journal, ESJ 14, no. 27 (September 30, 2018): 281. http://dx.doi.org/10.19044/esj.2018.v14n27p281.
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The maintenance and stability of many terrestrial ecosystems are in part related to the ecosystem functions and services of soil organisms. The present study aims to evaluate the influence of litter biomass produced by three types of vegetation in the Lamto reserve on the dynamics of earthworm community. Each vegetation formations has been subdivided into 3 parcels. These parcels were geo-referenced using a GPS and mapped using QGIS software. For each plot, 25 points were randomly selected using their GPS coordinates. The litters were collected by manual collection to evaluate their biomass. Monoliths of the TSBF (Tropical Soil Biology) type were dug in order to collect the earthworms by direct manual sorting. Also, soil clumps were collected to determine the organic matter levels by the method of lossto-fire. In total, 12 species of earthworms belonging to 3 ecological categories were collected. The forest block had the highest density of earthworms with a predominance of epigeic earthworms followed by grassy savannah with a predominance of endogeic earthworms. The wooded savannah has the lowest density of earthworms with a predominance of anecic earthworms. In terms of species richness, the grassy savannah contained the greatest number of earthworm species followed by the wooded savannah and the forest block that had the same number of species. In the three vegetations formations, it was found that earthworm densities were correlated with litter biomass as well as organic matter levels (correlation between earthworm density and litter biomass: r 2 =0, 75; correlation between density of earthworms and the rate of organic matter: r 2 =0, 93).
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Burbridge, Rachel E., Francis E. Mayle, and Timothy J. Killeen. "Fifty-thousand-year vegetation and climate history of Noel Kempff Mercado National Park, Bolivian Amazon." Quaternary Research 61, no. 2 (March 2004): 215–30. http://dx.doi.org/10.1016/j.yqres.2003.12.004.
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Pollen and charcoal records from two large, shallow lakes reveal that throughout most of the past 50,000 yr Noel Kempff Mercado National Park, in northeastern lowland Bolivia (southwestern Amazon Basin), was predominantly covered by savannas and seasonally dry semideciduous forests. Lowered atmospheric CO2 concentrations, in combination with a longer dry season, caused expansion of dry forests and savannas during the last glacial period, especially at the last glacial maximum. These ecosystems persisted until the mid-Holocene, although they underwent significant species reassortment. Forest communities containing a mixture of evergreen and semideciduous species began to expand between 6000 and 3000 14C yr B.P. Humid evergreen rain forests expanded to cover most of the area within the past 2000 14C yr B.P. coincident with a reduction in fire frequencies. Comparisons between modern pollen spectra and vegetation reveal that the Moraceae-dominated rain forest pollen spectra likely have a regional source area at least 2–3 km beyond the lake shore, whereas the grass- and sedge-dominated savanna pollen spectra likely have a predominantly local source area. The Holocene vegetation changes are consistent with independent paleoprecipitation records from the Bolivian Altiplano and paleovegetation records from other parts of southwestern Amazonia. The progressive expansion in rain forests through the Holocene can be largely attributed to enhanced convective activity over Amazonia, due to greater seasonality of insolation in the Southern Hemisphere tropics driven by the precession cycle according to the Milankovitch Astronomical Theory.
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Smith, Richard J., and Francis E. Mayle. "Impact of mid- to late Holocene precipitation changes on vegetation across lowland tropical South America: a paleo-data synthesis." Quaternary Research 89, no. 1 (November 10, 2017): 134–55. http://dx.doi.org/10.1017/qua.2017.89.
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AbstractA multi-proxy paleo-data synthesis of 110 sites is presented, exploring the impact of mid- to late Holocene precipitation changes upon vegetation across Southern Hemisphere tropical South America. We show that the most significant vegetation changes occurred in southwest Amazonia and southeast Brazil, regions reliant on precipitation derived from the South American summer monsoon (SASM). A drier mid-Holocene in these regions, linked to a weaker SASM, favored more open vegetation (savannah/grasslands) than present, while increased late-Holocene precipitation drove expansion of humid forests (e.g., evergreen tropical forest in southwest Amazonia,Araucariaforests in southeast Brazil). The tropical forests of central, western and eastern Amazonia remained largely intact throughout this 6000-year period. Northeastern Brazil’s climate is “antiphased” with the rest of tropical South America, but a lack of paleo-data limits our understanding of how vegetation responded to a wetter (drier) mid-(late) Holocene. From this paleo-data perspective, we conclude that ecotonal forests already close to their climatic thresholds are most vulnerable to predicted future drought, but the forest biome in the core of Amazonia is likely to be more resilient. Of greater concern are widespread deforestation and uncontrolled anthropogenic burning, which will decrease ecosystem resilience, making them more vulnerable than they might be without current anthropogenic pressures.
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Sulaiman, Muhammad Ikhsan, Rita Andini, Murna Muzaifa, Leni Marlina, Rachman Jaya, Ali M. Muslih, and Heru P. Widayat. "Making biodiversity work for coffee production. A case study of Gayo Arabica coffee in Indonesia." MOJ Ecology & Environmental Sciences 6, no. 4 (August 6, 2021): 156–62. http://dx.doi.org/10.15406/mojes.2021.06.00228.
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Biodiversity is defined as the variety of life encompassing the ‘existing’ variations at all level, starting from the tiny genes within a species up to a broader sense consisted of habitats within ecosystem. It is urgently needed as long as human is still exist on this earth. Therefore, its proper utilization and correct application of biodiversity bring great advantage in tangible and non-tangible benefits. Indonesia is known as the third largest biodiversity hotspots; both its flora and fauna. It has also tremendous diverse ecosystems extended from west to east; with amplitude of variation ranging from humid tropical rain forests until a very dry savannah type at the eastern part of Nusa Tenggara. Furthermore, Indonesia is also known as the fourth world highest producer of coffee; with a total production 11,49 million kg in 2016-2017. The Gayo highlands on the northern tip of Sumatra are known as the major production of arabica coffee. There, up to ten varieties of commercial arabica coffee are planted on the highlands. The origin of coffee is in Ethiopia, which is believed as the center of the commercial coffee species in this world: C. arabica and C. canephora. The objective of this paper is to review the status of coffee, esp. the arabica one from various perspectives, ranging from the biology, history of coffee, the processing of coffee (wet vs. dry methods), and how the component of natural biodiversity can be applied in order to enhance the coffee production, particularly on the Gayo highlands.
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Galy-Lacaux, C., D. Laouali, L. Descroix, N. Gobron, and C. Liousse. "Long term precipitation chemistry and wet deposition in a remote dry savanna site in Africa (Niger)." Atmospheric Chemistry and Physics 9, no. 5 (March 3, 2009): 1579–95. http://dx.doi.org/10.5194/acp-9-1579-2009.
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Abstract. Long-term precipitation chemistry have been recorded in the rural area of Banizoumbou (Niger), representative of a semi-arid savanna ecosystem. A total of 305 rainfall samples ~90% of the total annual rainfall) were collected from June 1994 to September 2005. From ionic chromatography, pH major inorganic and organic ions were detected. Rainwater chemistry is controlled by soil/dust emissions associated with terrigeneous elements represented by SO42−, Ca2+, Carbonates, K+ and Mg2+. It is found that calcium and carbonates represent ~40% of the total ionic charge. The second highest contribution is nitrogenous, with annual Volume Weighed Mean (VWM) for NO3− and NH4+ concentrations of 11.6 and 18.1 μeq.l−1, respectively. This is the signature of ammonia sources from animals and NOx emissions from savannas soil-particles rain-induced. The mean annual NH3 and NO2 air concentration are of 6 ppbv and 2.6 ppbv, respectively. The annual VWM precipitation concentration of sodium and chloride are both of 8.7 μeq.l−1 which reflects the marine signature of monsoonal and humid air masses. The median pH value is of 6.05. Acidity is neutralized by mineral dust, mainly carbonates, and/or dissolved gases such NH3. High level of organic acidity with 8μeq.l−1 and 5.2 μeq.l−1 of formate and acetate were also found. The analysis of monthly Black Carbon emissions and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) values show that both biogenic emission from vegetation and biomass burning could explain the rainfall organic acidity content. The interannual variability of the VWM concentrations around the mean (1994–2005) is between ±5% and ±30% and mainly due to variations of sources strength and rainfall spatio-temporal distribution. From 1994 to 2005, the total mean wet deposition flux in the Sahelian region is of 60.1 mmol.m−2.yr−1 ±25%. Finally, Banizoumbou measurements are compared to other long-term measurements of precipitation chemistry in the wet savanna of Lamto (Côte d'Ivoire) and in the forested zone of Zoétélé (Cameroon). The total chemical loading presents a maximum in the dry savanna and a minimum in the forest (from 143.7, 100.2 to 86.6 μeq.l−1), associated with the gradient of terrigeneous sources. The wet deposition fluxes present an opposite trend, with 60.0 mmol.m−2.yr−1 in Banizoumbou, 108.6 mmol.m−2.yr−1 in Lamto and 162.9 mmol.m−2.yr−1 in Zoétélé, controlled by rainfall gradient along the ecosystems transect.
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Davidson, Eric A., Mercedes M. C. Bustamante, and Alexandre de Siqueira Pinto. "Emissions of Nitrous Oxide and Nitric Oxide from Soils of Native and Exotic Ecosystems of the Amazon and Cerrado Regions of Brazil." Scientific World JOURNAL 1 (2001): 312–19. http://dx.doi.org/10.1100/tsw.2001.261.
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This paper reviews reports of nitrous oxide (N2O) and nitric oxide (NO) emissions from soils of the Amazon and Cerrado regions of Brazil. N2O is a stable greenhouse gas in the troposphere and participates in ozone-destroying reactions in the stratosphere, whereas NO participates in tropospheric photochemical reactions that produce ozone. Tropical forests and savannas are important sources of atmospheric N2O and NO, but rapid land use change could be affecting these soil emissions of N oxide gases. The five published estimates for annual emissions of N2O from soils of mature Amazonian forests are remarkably consistent, ranging from 1.4 to 2.4 kg N ha–1 year–1, with a mean of 2.0 kg N ha–1 year–1. Estimates of annual emissions of NO from Amazonian forests are also remarkably similar, ranging from 1.4 to 1.7 kg N ha–1 year–1, with a mean of 1.5 kg N ha–1 year–1. Although a doubling or tripling of N2O has been observed in some young (<2 years) cattle pastures relative to mature forests, most Amazonian pastures have lower emissions than the forests that they replace, indicating that forest-topasture conversion has, on balance, probably reduced regional emissions slightly (<10%). Secondary forests also have lower soil emissions than mature forests. The same patterns apply for NO emissions in Amazonia. At the only site in Cerrado where vegetation measurements have been made N2O emissions were below detection limits and NO emissions were modest (~0.4 kg N ha–1 year–1). Emissions of NO doubled after fire and increased by a factor of ten after wetting dry soil, but these pulses lasted only a few hours to days. As in Amazonian pastures, NO emissions appear to decline with pasture age. Detectable emissions of N2O have been measured in soybean and corn fields in the Cerrado region, but they are modest relative to fluxes measured in more humid tropical agricultural regions. No measurements of NO from agricultural soils in the Cerrado region have been made, but we speculate that they could be more important than N2O emissions in this relatively dry climate. While a consistent pattern is emerging from these studies in the Amazon region, far too few data exist for the Cerrado region to assess the impact of land use changes on N oxide emissions.
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Galy-Lacaux, C., D. Laouali, L. Descroix, N. Gobron, and C. Liousse. "Long term precipitation chemistry and wet deposition in a remote dry savanna site in Africa (Niger)." Atmospheric Chemistry and Physics Discussions 8, no. 2 (March 19, 2008): 5761–812. http://dx.doi.org/10.5194/acpd-8-5761-2008.
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Abstract. A long-term measurement of precipitation chemistry has been carried-out in a rural area of Banizoumbou, in the Sahel (Niger), representative of the african semi-arid savanna ecosystem. A total of 305 rainfall samples, representing 90% of the total annual rainfall, were collected with an automatic wet-only rain sampler from June 1994 to September 2005. Using ionic chromatography, pH major inorganic and organic ions were analyzed. Rainwater chemistry at the site is controlled by soil dust emissions associated to a strong terrigeneous contribution represented by SO42–, Ca2+, Carbonates, K+ and Mg2+. Calcium and carbonates represent about 40% of the total ionic charge of precipitation. The second highest contribution is nitrogenous, with annual Volume Weighed Mean (VWM) NO3– and NH4+, concentrations of 11.6 and 18.1 μeq.l−1, respectively. This is thesignature of ammonia sources related to animals and NOx emissions from savannas soils rain-induced, at the beginning of the rainy season. The mean annual NH3 and NO2 air concentration are of 6 ppbv and 2.6 ppbv, respectively. The annual VWM precipitation concentration of sodium and chloride are both of 8.7 μeq.l−1 and reflects the marine signature from the monsoon humid air masses coming from the ocean. The mean pH value, calculated from the VWM of H+, is 5.64. Acidity is neutralized by mineral dust, mainly carbonates, and/or dissolved gases such NH3. High level of organic acidity with 8 μeq.l−1 and 5.2 μeq.l−1 of formate and acetate were found, respectively. The analysis of monthly Black Carbon emissions and FAPAR values show that both biogenic emission from vegetation and biomass burning sources could explain the organic acidity content of the precipitation. The interannual variability of the VWM concentrations around the mean (1994–2005) presents fluctuations between ±5% and ±30% mainly attributed to the variations of sources strength associated with rainfall spatio-temporal distribution. From 1994 to 2005, the total mean wet deposition flux in the Sahelian region is 60.1 mmol.m−2.yr−1 and fluctuates around ±25%. Finally, Banizoumbou measurements, are compared to other long-term measurements of precipitation chemistry in the wet savanna of Lamto (Côte d'Ivoire) and in the forested zone of Zoétélé (Cameroon). The total chemical loadings presents a strong negative gradient from the dry savanna to the forest (143.7, 100.2 to 86.6 μeq.l–1), associated with the gradient of terrigeneous compounds sources. The wet deposition fluxes present an opposite gradient, with 60.0 mmol.m−2.yr−1 in Banizoumbou, 108.6 mmol.m−2.yr–1 in Lamto and 162.9 mmol.m−2.yr−1 in Zoétélé, controlled by the rainfall gradient along the ecosystems transect.
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Saraiva, Sarah O., Ian D. Rutherfurd, Philip R. Kaufmann, Cecília G. Leal, Diego R. Macedo, and Paulo S. Pompeu. "Wood stock in neotropical streams: Quantifying and comparing instream wood among biomes and regions." PLOS ONE 17, no. 10 (October 5, 2022): e0275464. http://dx.doi.org/10.1371/journal.pone.0275464.
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Instream wood plays important chemical, physical and ecological functions in aquatic systems, benefiting biota directly and indirectly. However, human activities along river corridors have disrupted wood recruitment and retention, usually leading to reductions in the amount of instream wood. In the tropics, where wood is believed to be more transient, the expansion of agriculture and infrastructure might be reducing instream wood stock even more than in the better studied temperate streams. However, research is needed to augment the small amount of information about wood in different biomes and ecosystems of neotropical streams. Here we present the first extensive assessment of instream wood loads and size distributions in streams of the wet-tropical Amazon and semi-humid-tropical Cerrado (the Brazilian savanna). We also compare neotropical wood stocks with those in temperate streams, first comparing against data from the literature, and then from a comparable dataset from temperate biomes in the USA. Contrary to our expectations, Amazon and Cerrado streams carried similar wood loads, which were lower than the world literature average, but similar to those found in comparable temperate forest and savanna streams in the USA. Our results indicate that the field survey methods and the wood metric adopted are highly important when comparing different datasets. But when properly compared, we found that most of the wood in temperate streams is made-up of a small number of large pieces, whereas wood in neotropical streams is made up of a larger number of small pieces that produce similar total volumes. The character of wood volumes among biomes is linked more to the delivery, transport and decomposition mechanisms than to the total number of pieces. Future studies should further investigate the potential instream wood drivers in neotropical catchments in order to better understand the differences and similarities here detected between biomes and climatic regions.
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Rija, Alfan A., Abubakari S. Mgelwa, Robert B. Modest, and Shombe N. Hassan. "Composition and Functional Diversity in Bird Communities in a Protected Humid Coastal Savanna." Advances in Zoology 2015 (December 9, 2015): 1–7. http://dx.doi.org/10.1155/2015/864219.
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Our current understanding of the vertebrate communities of a newly gazetted Tanzanian coastal national park is limited and strongly taxonomically biased towards large mammals. We conducted bird assessments in three sites in Saadani National Park using species lists to analyze some parameters to inform biodiversity conservation in the area. We recorded 3112 individuals in 268 species falling in 66 families, including 2 endangered, 2 vulnerable, and 6 near threatened species. Both species richness and species diversity varied between sites. Species relative abundances were not different between the sites although some functional groups, especially granivores, were more abundant than others. Bird assemblages included 21 forest specialists (FF-species), 35 forest generalists (F-species), and 68 forest visitors (f-species) overlapping among bushland, wooded grassland, grassland, and thickets suggesting presence of important microhabitats for the forest-associated species in this ecosystem. Bird species richness in a feeding guild also showed marked overlap between habitats suggesting availability of rich food resources for the birds. This paper highlights the importance of maintaining a structurally heterogeneous landscape to sustain diverse bird communities in the area.
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SEO, S. N. "A geographically scaled analysis of adaptation to climate change with spatial models using agricultural systems in Africa." Journal of Agricultural Science 149, no. 4 (March 25, 2011): 437–49. http://dx.doi.org/10.1017/s0021859611000293.
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SUMMARYThe present paper provides a geographically scaled analysis of adaptation to climate change using adoption of agricultural systems observed across Africa. Usingc. 9000 farm surveys, spatial logit models were applied to explain observed agricultural system choices by climate variables after accounting for soils, geography and other household characteristics. The results reveal that strong neighbourhood effects exist and a spatial re-sampling and bootstrapping approach can remove them. The crops-only system is adopted most frequently in the lowland humid forest, lowland sub-humid, mid-elevation sub-humid Agro-Ecological Zones (AEZs) and in the highlands in the east and in southern Africa. Integrated farming is favoured in the lowland dry savannah, moist savannah and semi-arid zones in West Africa and eastern coastal zones. A livestock-only system is favoured most in the mid/high-elevation moist savannahs located in southern Africa. Under a hot and dry Canadian Climate Centre (CCC) scenario, the crops-only system should move out from the currently favoured regions of humid zones in the lowlands towards the mid-/high elevations. It declines by more than 5% in the lowland savannahs. Integrated farming should increase across all the AEZs by as much as 5%, but less so in the deserts or in the humid forest zones in the mid-/high elevations. A livestock-only system should increase by 2–5% in the lowland semi-arid, dry savannah and moist savannah zones in the lowlands. Adaptation measures should be carefully scaled, up or down, considering geographic and ecological differentials as well as household characteristics, as proposed in the present study.
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Pessenda, L. C. R., S. E. M. Gouveia, Ramon Aravena, B. M. Gomes, Rene Boulet, and A. S. Ribeiro. "14C Dating and Stable Carbon Isotopes of Soil Organic Matter in Forest–Savanna Boundary Areas in the Southern Brazilian Amazon Region." Radiocarbon 40, no. 2 (1997): 1013–22. http://dx.doi.org/10.1017/s0033822200018981.
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This study, which was carried out in the southern Brazilian Amazon region (Rondônia state and Humaitá, Southern Amazon state), presents and discusses the significance of carbon isotope data measured in soil profiles collected across natural boundaries of forest to savanna vegetation. The main objective of this study was to evaluate the expansion-regression dynamics of these vegetation units in relation to climate changes during the Holocene. 14C data from charcoal, soil organic matter (SOM) and its component humin fraction indicate that the organic matter in the studied soils is essentially Holocene in origin. 13C data indicate that C3 type plants were the dominant vegetation at all study areas in the early Holocene, and during the entire Holocene, in the forest sites of Central Rondônia state and in the forest site 50 km from the city of Humaitá. 13C data also indicate that C4 plants have influenced significantly the vegetation at the transitional forest and the Cerrado (wooded savanna) sites of Southern Rondônia state and the forest ecosystem located 20 km from the Humaitá city. These typical C4 type isotopic signatures probably reflect a drier climate during the mid-Holocene. The 13C records representing probably the last 3000 yr show an expansion of the forest, due to a climatic improvement, in areas previously occupied by savanna vegetation. These results and other published data for the Amazon region indicate that the areas representing today's forest-savanna boundaries have been determined by significant vegetation changes during the Holocene. The boundary between forest and savanna vegetation seems to be quite sensitive to climatic change and should be the focus of more extensive research to correlate climate and past vegetation dynamics in the Amazon region.
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DUARTE-ALMEIDA, JOAQUIM M., MILENE S. CLEMENTE, ROSANI C. O. ARRUDA, ANGELA M. S. F. VAZ, and ANTONIO SALATINO. "Glands on the foliar surfaces of tribe Cercideae (Caesapiniodeae, Leguminosae): distribution and taxonomic significance." Anais da Academia Brasileira de Ciências 87, no. 2 (June 2015): 787–96. http://dx.doi.org/10.1590/0001-3765201520140151.
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Large elongated glands occur on Cercideae leaf surfaces. Leaves of Bauhinia (55 taxa, 53 species), Cercis (1 species), Phanera (1 species), Piliostigma (2 species), Schnella (19 species) and Tylosema (1 species) were observed to determine location and relative number of glands. They were only observed on the abaxial leaf surface of 42 Bauhinia taxa. The glands were analyzed by light stereomicroscope and scanning electron microscopy. They are large (up to 270 µm long and 115 µm wide) and multicellular, containing lipophilic substances, probably volatile oils. Presence or absence and density of the glands in species of Bauhinia may be useful to determine species delimitation or distinction among infraspecific taxa. Higher density of glands is more common in species from "cerrado" (a savanna ecosystem) and "caatinga" (a semiarid ecosystem from northeast Brazil) areas. Bauhinia species devoid of foliar glands are frequently from humid forests.
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Wu, Haohao, Congsheng Fu, Lingling Zhang, and Huawu Wu. "Elevated Wildfire and Ecosystem Carbon Loss Risks Due to Plant Hydraulic Stress Functions: A Global Modeling Perspective." Fire 5, no. 6 (November 5, 2022): 187. http://dx.doi.org/10.3390/fire5060187.
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Wildfire risks are increasing due to the atmospheric and vegetation aridity under global warming. Plant hydraulic stress (PHS) functions regulate water transport along the soil–plant–atmosphere continuum under water stress conditions, which probably results in shifts in ecosystem wildfire regimes. Currently, how the PHS functions affect wildfire occurrence and subsequently the ecosystem carbon cycle via carbon loss at a global scale remains unclear. Here, we conducted global simulations during 1850–2010 using Community Land Model version 5 with and without the PHS configuration and quantified the PHS-induced changes. From the global perspective, the PHS functions increased plant transpiration, induced hydraulic redistribution (HR) of soil water by root, and decreased soil moisture; then, the functions increased fire occurrence (count), fire induced carbon loss, and ecosystem net primary productivity by 72%, 49%, and 15%, respectively. Spatially, the PHS functions greatly promoted fire occurrence and the consequent carbon loss in circumboreal forests and tropical savannas; whereas, the fire occurrence was limitedly affected or even decreased in equatorial rainforests. The strong downward HR process in the humid rainforests transported rainwater into deep soil layers, and strict stomatal regulation of the tropical trees restricted transpiration increment under atmospheric aridity, both of which helped to buffer the rainforests against drought and thus decreased fire risk. In contrast, dry savannas showed substantial upward HR, which increased water loss via soil evaporation and transpiration of the grasses with shallow roots. The tree–grass competition for limited soil moisture in the savannas benefited soil evaporation, which could aggravate plant hydraulic failure and increase wildfire risk.
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Yli-Panula, Eija, and Eila Matikainen. "STUDENTS AND STUDENT TEACHERS´ ABILITY TO NAME ANIMALS IN ECOSYSTEMS: A PERSPECTIVE OF ANIMAL KNOWLEDGE AND BIODIVERSITY." Journal of Baltic Science Education 13, no. 4 (August 25, 2014): 559–72. http://dx.doi.org/10.33225/jbse/14.13.559.
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In this survey Finnish lower and upper secondary education students´ and student teachers´ (n=514) knowledge of the animal names (species) in relation to ecosystems was studied using a questionnaire. The results were interpreted with regard to the biodiversity of the ecosystem. Nordic fen, spruce-dominated coniferous forest, tropical rainforest, and savannah were studied. The respondents were aware of animals living in the four ecosystems, especially of mammals and birds. The animals of the indigenous Nordic fen were the least known, as evidenced by the low average number of the names and the highest number of falsely named animals. Furthermore, the animals of the savannah were the best known by the students in lower and upper secondary education, while the animals of the spruce-dominated coniferous forest were best known by student teachers. The invertebrates were nearly forgotten from all ecosystems, although they are an essential part of biodiversity and food chain/web. Research results show that students’ knowledge of the animals in relation to their autecological matters should be improved in all information sources provided. Key words: animals, biodiversity, ecosystem, Finnish students in lower and upper secondary education, Finnish student teachers
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Victor, Awé Djongmo, Noiha Noumi Valery, and Zapfack Louis. "Floristic structure and ecological role of Rourea afzelii stand in three savannah ecosystems from Cameroon." Journal of Tropical Resources and Sustainable Science (JTRSS) 8, no. 1 (July 13, 2021): 5–11. http://dx.doi.org/10.47253/jtrss.v8i1.157.
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The present study investigated the floristic structure and ecological role of Rourea afzelii stands insavannah, forest galleries and swampy areas to Cameroon. An 80 m x 50 m transect method wasundertaken to measure floristic diversity using Shannon index, Pielou equitability, Simpson’s indexand the importance value index. The structure of Rourea afzelii stands is determined by density,basal area and biovolume. The results of this study show that Rourea afzelii stands are morediversified in savannah with a Shannon diversity index (ISH =4 ± 0.03bit). The highest log stabilityof Rourea afzelii stands is observed in the savannah (EQ=0.75 ± 0.008). The Simpson index of theRourea afzelii stands is larger in the forest gallery (D=0.088 ± 0.0022). Rourea afzelii Stands aredenser in savannah (113 ± 2.54 individuals/ha). The basal area and biovolume of Rourea afzeliistands are very high in swamp area (St=15.75 ± 0.02 m2/ha, Biov=9.08 ± 0.12 m3/ha). The diametricstructure has an asymmetrical “L” shaped appearance, indicating a strong regeneration of Roureaafzelii Stands in the three sites studied. Rourea afzelii Stands in forest galleries sequestered morecarbon (26.41 ± 0.0015 ton C/ha) than those in savannahs and swampy areas. This valuecorresponds to sequestration of carbon dioxide of 96.92 ± 0.82 ton CO2/ha. Economically, thiscorresponds to the CDM carbon price (290.77± 3.332 Euros/ha), a Voluntary Market Carbon Priceof 455.54 ± 1.908 Euros/ha, a REDD + carbon price of 9692 ± 8.152 Euros/ha. In conclusion, theresults of this study can be used in the context of protection and conservation as well as thedomestication of such a species.
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Liang, Siqi, Shouzhang Peng, and Yunming Chen. "Carbon Cycles of Forest Ecosystems in a Typical Climate Transition Zone under Future Climate Change: A Case Study of Shaanxi Province, China." Forests 10, no. 12 (December 16, 2019): 1150. http://dx.doi.org/10.3390/f10121150.
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As global climate change has a large effect on the carbon cycle of forests, it is very important to understand how forests in climate transition regions respond to climate change. Specifically, the LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator) model was used to simulate net ecosystem productivity (NEP) and soil heterotrophic respiration (Rh) dynamics of two forest ecosystems of different origins between 1951 and 2100, to quantitatively analyze the carbon source and sink functions and potential changes in soil carbon dynamics in arid and humid regions under future climate change, simulate the dynamics of forest net primary productivity (NPP) under different climatic factors, and analyze the sensitivity of forests in arid and humid regions to temperature, precipitation, and carbon dioxide (CO2) concentration. We found that: (1) in both the historical and future periods, the average NEP of both studied forests in the humid region was larger than that in the arid region, the carbon sink function of the humid region being predicted to become stronger and the arid zone possibly becoming a carbon source; (2) between 1951 and 2100, the forest soil Rh in the arid region was lower than that in the humid region and under future climate change, forest in the humid region may have higher soil carbon loss; (3) increasing temperature had a negative effect and CO2 concentration had a positive effect on the forests in the study area, and forests in arid areas are more sensitive to precipitation change. We believe our research could be applied to help policy makers in planning sustainable forest management under future climate change.
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de la Cruz, Marcelino, Pedro F. Quintana-Ascencio, Luis Cayuela, Carlos I. Espinosa, and Adrián Escudero. "Comment on “The extent of forest in dryland biomes”." Science 358, no. 6364 (November 9, 2017): eaao0369. http://dx.doi.org/10.1126/science.aao0369.
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The study by Bastin et al. (Reports, 12 May 2017, p. 635) is based on an incomplete delimitation of dry forest distribution and on an old and incorrect definition of drylands. Its sampling design includes many plots located in humid ecosystems and ignores critical areas for the conservation of dry forests. Therefore, its results and conclusions may be unreliable.
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Donica, Ala, Valentin Raileanu, and Nicolae Grigoras. "Forest ecosystems’ vulnerability of Emerald site “Pădurea Hîncești” to climate change." Bulletin of the Academy of Sciences of Moldova Life Sciences, no. 1(345) (July 2022): 125–36. http://dx.doi.org/10.52388/1857-064x.2022.1.16.
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The Emerald site “Pădurea Hîncești” is located in central part of the Republic of Moldova territory and contains forest ecosystems dominated by oak species (the most valuable species of the national forest fund). Scientific research on the assessment of the protected forest ecosystems vulnerability, under the impact of climate change, using ecoclimate indices (De Martonne Aridity Index – IM; Conventional Humidity Balance – K; and Ellenberg Quotient - EQ) and mapping of obtained results, are very current and important in forest sustainable development. The study determined that, per general, Emerald site has climatic conditions favorable for growth and development of forest ecosystems on the entire surface (the K index values being above unit, for the period when the air temperature was ≥ 10°C). IM values calculated for the Emerald site (19912020) range from 24.2 to 37.0 units, framed territories from semi-arid climatic conditions, to humid climatic conditions, favorable for the development of steppe and forest communities. In Emerald site, there are two areas of forest vulnerability to climate aridity: high vulnerability level, within moderately arid climate and lasting disturbances of the moisture; and medium vulnerability level, within slightly humid climate and disturbances of the moisture in some years. Based on the IM temporal trends, there is future risk to pass from a medium to a high forest vulnerability to climate change in almost all site. The EQ values vary between 29.5 and 46.0 units (developing climate conditions favorable for oak-hornbeam forests development growth in the northern side of site; for oak forests - in the central part, and for dry / arid oak forests -in the southern part). Concerns about the sustainable management of the forest sector and the expansion of forest areas with tree species adapted to new environmental conditions must be a constant in the country's sectoral priorities.
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Plumpton, Heather, Bronwen Whitney, and Francis Mayle. "Ecosystem turnover in palaeoecological records: The sensitivity of pollen and phytolith proxies to detecting vegetation change in southwestern Amazonia." Holocene 29, no. 11 (July 12, 2019): 1720–30. http://dx.doi.org/10.1177/0959683619862021.
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Identification of ecosystem turnover in the palaeo-vegetation record is important for understanding the resilience of ecosystems to past environmental change. There is uncertainty over the ability of different types of palaeo-vegetation proxies to detect ecosystem turnover. The aim of this paper is to compare the sensitivity of two palaeo-vegetation proxies – pollen and phytoliths – to changes within and between three key tropical South American ecosystems: evergreen forest, dry forest and savannah. A quantitative approach is used to assess the sensitivity of these two proxies to vegetation changes, based on the variability of proxy assemblages from 1-ha ecological plots in ecotonal south-west Amazonia. This modern dataset of proxy variability within evergreen forest, dry forest and savannah plots is then used to define thresholds for proxy variability which differentiate floristic changes within an ecosystem from ecosystem turnover. These thresholds are applied to two palaeo-vegetation records from NE Bolivia. Our results show that pollen is more sensitive than phytoliths to changes within evergreen forest, but phytoliths are more sensitive than pollen to changes within dry forest. Both proxies were equally sensitive to changes within the savannahs. These are important considerations for palaeoecologists selecting proxies for the study of ecosystem turnover in the palaeo-record. Application of the thresholds to the palaeo-record demonstrated the utility of this quantitative approach for assessing the magnitude of vegetation change in the palaeo-record. This quantitative approach is therefore a useful tool to improve the identification of ecosystem turnover in the palaeo-record.
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CAMPBELL, MICHAEL O'NEAL. "Traditional forest protection and woodlots in the coastal savannah of Ghana." Environmental Conservation 31, no. 3 (September 2004): 225–32. http://dx.doi.org/10.1017/s0376892904001389.
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There is increased international interest in religiously based restrictions on land and forest stand use. However, the extent to which so-called sacred groves represent earlier forest ecosystems, and their possible role in biodiversity conservation, are interrelated and complex issues, and neglected in the context of Ghanaian savannahs, which are believed to be in transition from a forested past. Geographical information system (GIS) analysis of time-series images, aerial photographs, statistical analysis of ecological field data and social surveys were used to investigate the Ghanaian savannah. Sacred groves were found to be similar in plant species content and structure to the deciduous forest of southern Ghana. Between 1960 and 1996, these groves experienced far fewer forest losses than unprotected tree stands (<20%, as opposed to up to 100%). Non-sacred groves also contained lower plant species richness and higher numbers of invasive species such as neem (Azadirachta indica A. Juss). Sacred groves, while dependent on respect for religion, local cultural structures and individual peer pressure, offer a role that may support and also be supported by official conservation efforts.
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OLIVEIRA, ANIBAL R., ROY A. NORTON, and GILBERTO J. DE MORAES. "Edaphic and plant inhabiting oribatid mites (Acari: Oribatida) from Cerrado and Mata Atlantica ecosystems in the State of São Paulo, southeast Brazil." Zootaxa 1049, no. 1 (September 13, 2005): 49. http://dx.doi.org/10.11646/zootaxa.1049.1.4.
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Forest sites in the eastern half of the State of São Paulo were surveyed to determine the oribatid mite fauna in areas of Cerrado (dry savannah) and Mata Atlântica (tropical rain forest) ecosystems. Samples of bark, fruits, leaves, litter, soil and terminal shoots were taken from selected species of Myrtaceae (Cerrado) and Arecaceae (Mata Atlântica). Fifty-six oribatid species, belonging to 48 genera in 34 families, were represented. Seven of these are new records for the State of São Paulo, and 20 are new records for Brazil.
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Kenfack Essougong, Urcil P., Maja Slingerland, Syndhia Mathé, Wouter Vanhove, Precillia I. Tata Ngome, Philippe Boudes, Ken E. Giller, Lotte S. Woittiez, and Cees Leeuwis. "Farmers’ Perceptions as a Driver of Agricultural Practices: Understanding Soil Fertility Management Practices in Cocoa Agroforestry Systems in Cameroon." Human Ecology 48, no. 6 (November 20, 2020): 709–20. http://dx.doi.org/10.1007/s10745-020-00190-0.
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AbstractIn Africa, cocoa yields are low, partly due to soil fertility constraints and poor management. While peoples’ knowledge, aspirations, and abilities are key factors explaining their behaviour, little is known about the rationales that underpin soil fertility management practices (SFMPs) of cocoa farmers. To address this gap, we conducted an exploratory survey in two contrasting regions in Cameroon where cocoa is an important crop: the humid forest and the forest-savannah transition zone. Some 30% of farmers in the transition zone as opposed to 13% in the humid forest expressed concerns about soil fertility. The most relevant soil fertility indicators for farmers were high cocoa yield, dark soil colour, ease of tillage, and floral composition. To enhance and maintain soil fertility, farmers used residues from weeding (100%), planting of trees (42%), mineral fertilisers (33%), compost (16%), and manure (13%). More farmers in the transition zone than the humid forest implemented SFMPs. Our findings suggest that soil fertility perceptions, access to inputs, local practices, and experience influence farmers’ use of SFMPs. The limited use of mineral fertilisers was explained by poor access whereas the use of organic fertilisers and tree planting were mostly constrained by lack of labour and knowledge. Farmers prioritised practices to increase yield and viewed SFMPs to be the least important management practices, although they believe high cocoa yield is an important indicator of soil fertility. To foster sustainable cocoa intensification, it is necessary to enhance farmers’ knowledge on SFMPs, increase access to inputs, and ensure returns on investment while considering farmers’ priorities and practices.
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Scherbina, V. G. "Dynamics of allelopatic soil effects in forest eco-systems with a monodominant forest stand after simulation of recreational load." Monitoring systems of environment, no. 1 (March 28, 2022): 94–104. http://dx.doi.org/10.33075/2220-5861-2022-1-94-104.
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The dynamics of allelopathic effects of the soil was assessed within seven months of the growing season after simulating a one-time recreational load in seven forest ecosystems of the humid subtropics of the Sochi Black Sea region. Using the index of allelopathic activity of the soil and the index of the relative allelopathic effect, the seasonal dynamics of stimulation and inhibition of the growth processes of the biotest was traced, depending on the presence of a certain tree species, the magnitude of a one-time recreational load and the time elapsed since anthropogenic impact. The rows of forest ecosystems were compiled in terms of the resistance of edaphic conditions to recreational impact and the resistance to the introduction of new species under the canopy of the forest stand in the range of recreational loads of 1.39–8.33 people/ha.
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Quamar, Mohammad Firoze, Ratan Kar, and Biswajeet Thakur. "Vegetation response to the Indian Summer Monsoon (ISM) variability during the Late-Holocene from the central Indian core monsoon zone." Holocene 31, no. 7 (April 16, 2021): 1197–211. http://dx.doi.org/10.1177/09596836211003191.
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Pollen analysis and radiocarbon dating of a 1.4 m deep lacustrine sediment profile from Chhattisgarh State, central India, in the core monsoon zone (CMZ), has revealed the vegetation history, associated climate change and the Indian Summer Monsoon (ISM) rainfall variability during the Late-Holocene. The pollen evidence suggests that between ca. 3000 and 2600 cal year BP, tree-savannah vegetation occurred in the region having a comparatively lesser monsoon rainfall. The forest expanded and culminated into an open-mixed tropical deciduous forest between ca. 2600 and 2200 cal year BP under a warm and moderately humid climate with an increase in monsoon rainfall. Subsequently, between ca. 2200 and 2000 cal year BP, the existing open-mixed tropical deciduous forest transformed into a mixed tropical deciduous forest under a warm and humid climate with further increase in monsoon rainfall. Finally, between ca. 2000 and 1800 cal year BP, a dense mixed tropical deciduous forest occupied the landscape under a regime of a warm and relatively more humid climate with further strengthening of the ISM. The gradual warming, and the climatic amelioration with the intensification of the ISM, during the Late-Holocene (ca. 2600–1800 cal year BP; ~650 BC to AD150) corresponds to the Roman Warm Period (RWP), recorded globally between 2500 and1600 cal year BP (~550 BC to AD ~350). Human activities were present around the study area, which varied according to the ISM variations. The present study provides insights into the gradual intensification of the monsoon since the last ca. 2600 cal year BP (between ca. 2600 and1800 cal year BP), and an increase in the ISM strength in the CMZ of India, against the generally weakening trend during the Late-Holocene.
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Bosu, Paul P., Mary M. Apetorgbor, Elvis E. Nkrumah, and Kwabena P. Bandoh. "The impact ofBroussonetia papyrifera(L.) vent. on community characteristics in the forest and forest-savannah transition ecosystems of Ghana." African Journal of Ecology 51, no. 4 (January 29, 2013): 528–35. http://dx.doi.org/10.1111/aje.12063.
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APTROOT, André, Marcela E. S. CÁCERES, Mark K. JOHNSTON, and Robert LÜCKING. "How diverse is the lichenized fungal familyTrypetheliaceae(Ascomycota: Dothideomycetes)? A quantitative prediction of global species richness." Lichenologist 48, no. 6 (November 2016): 983–94. http://dx.doi.org/10.1017/s0024282916000463.
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AbstractA quantitative prediction of global species richness in the lichenized familyTrypetheliaceaeemploying a grid method previously used in similar approaches for the familyGraphidaceaeand the genusCora(Hygrophoraceae) is provided. 421 currently known taxa were used as a base for the calculation and we predict a total of nearly 800 species, corresponding to an increase of almost 100%. Most of the unrecognized taxa are predicted to occur in the Neotropics, which have the highest known species richness. The Palaeotropics are less diverse. In contrast toGraphidaceae, which are mostly confined to rainforests,Trypetheliaceaeshow substantial species richness in dry forest and savannah ecosystems, and future collection efforts should take well-preserved areas representing such ecosystems into consideration.
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Martin, Konrad, and Michael Sommer. "Relationships between land snail assemblage patterns and soil properties in temperate-humid forest ecosystems." Journal of Biogeography 31, no. 4 (March 22, 2004): 531–45. http://dx.doi.org/10.1046/j.1365-2699.2003.01005.x.
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Oliveras, Immaculada, and Yadvinder Malhi. "Many shades of green: the dynamic tropical forest–savannah transition zones." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1703 (September 19, 2016): 20150308. http://dx.doi.org/10.1098/rstb.2015.0308.
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The forest–savannah transition is the most widespread ecotone in tropical areas, separating two of the most productive terrestrial ecosystems. Here, we review current understanding of the factors that shape this transition, and how it may change under various drivers of local or global change. At broadest scales, the location of the transition is shaped by water availability, mediated strongly at local scales by fire regimes, herbivory pressure and spatial variation in soil properties. The frequently dynamic nature of this transition suggests that forest and savannah can exist as alternative stable states, maintained and separated by fire–grass feedbacks and tree shade–fire suppression feedback. However, this theory is still contested and the relative contributions of the main biotic and abiotic drivers and their interactions are yet not fully understood. These drivers interplay with a wide range of ecological processes and attributes at the global, continental, regional and local scales. The evolutionary history of the biotic and abiotic drivers and processes plays an important role in the current distributions of these transitions as well as in their species composition and ecosystem functioning. This ecotone can be sensitive to shifts in climate and other driving factors, but is also potentially stabilized by negative feedback processes. There is abundant evidence that these transitions are shifting under contemporary global and local changes, but the direction of shift varies according to region. However, it still remains uncertain how these transitions will respond to rapid and multi-faceted ongoing current changes, and how increasing human influence will interact with these shifts. This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.
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Zhu, Ping, Wei Cao, Lin Huang, Tong Xiao, and Jun Zhai. "The Impacts of Human Activities on Ecosystems within China’s Nature Reserves." Sustainability 11, no. 23 (November 23, 2019): 6629. http://dx.doi.org/10.3390/su11236629.
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Protected areas (PAs) provide refuges for threatened species and are considered to be the most important approach to biodiversity conservation. Besides climate change, increasing human population is the biggest threat to biodiversity and habitats in PAs. In this paper, the temporal and spatial variations of land cover changes (LCC), vegetation fraction (VFC), and net primary productivity (NPP) were studied to present the ecosystem dynamics of habitats in 6 different types of national nature reserves (NNRs) in 8 climate zones in China. Furthermore, we used Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime light datasets and the human disturbance (HD) index estimated from LCC to quantify the living and developing human pressures within the NNRs in the period 2000–2013. The results showed that (1) the living human activities of NNRs increased apparently in the humid warm-temperate zone, Qinghai-Tibet Plateau, mid-temperate semi-arid zone, and mid-temperate humid zone, with the highest increase of nighttime light observed in inland wetlands; (2) the developing human activities in NNRs indicated by the HD index were higher in the humid warm-temperate zone and mid-temperate semi-arid zone as a result of increasing areas of agricultural and built activities, and lower in the sub-tropics due to improved conservation of forest ecosystems; (3) the relationship between HD and VFC suggests that ecosystems in most NNRs of south-subtropics, mid-temperate arid zone and Qinghai-Tibet Plateau were predominantly impacted by climate change. However, HDs were the prevalent factor of ecosystem dynamics in most NNRs of north-subtropics, mid-temperate semi-arid and humid zones.
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Ssemmanda, I., V. Gelorini, and D. Verschuren. "Sensitivity of the grassland-forest ecotone in East African open woodland savannah to historical rainfall variation." Climate of the Past Discussions 10, no. 2 (April 11, 2014): 1675–706. http://dx.doi.org/10.5194/cpd-10-1675-2014.
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Abstract. Fossil pollen records provide key insight into the sensitivity of terrestrial ecosystems to climate change at longer time scales. However, tracing vegetation response to relatively modest historical climate fluctuations is often complicated by the overriding signature of anthropogenic landscape disturbance. Here we use high-resolution pollen data from a ~200 year lake-sediment record in open woodland savannah of Queen Elisabeth National Park (southwestern Uganda) to assess the sensitivity of the tropical lowland grassland-forest ecotone to historical fluctuations in annual rainfall on the order of 10% lasting several decades. Specifically we trace vegetation response to three episodes of increased regional rainfall dated to the 1820s–1830s, ca. 1865–1890 and from 1962 to around 2000. During inferred wetter episodes we find increases in the relative pollen abundance from trees and shrubs of moist semi-deciduous forest (Allophylus, Macaranga, Celtis, Alchornea), riparian forest (Phoenix reclinata) and savannah woodland (Myrica, Acalypha, Combretaceae/Melostomataceae) as well as local savannah taxa (Acacia, Rhus type vulgaris, Ficus), together creating strong temporary reductions in Poaceae pollen (to 45–55% of the terrestrial pollen sum). During intervening dry episodes, most notably the period ca. 1920–1962, Poaceae pollen attained values of 65–75%, and dryland herbs such as Commelina, Justicia type odora and Chenopodiaceae expanded at the expense of Asteraceae, Solanum-type, Swertia usumbarensis-type, and (modestly so) Urticaceae. Noting that the overall diversity of arboreal taxa remained high but their combined abundance low, we conclude that the landscape surrounding Lake Chibwera has been an open woodland savannah throughout the past 200 years, with historical rainfall variation exerting modest effects on local tree cover (mostly the abundance of Acacia and Ficus) and the prevalence of damp soil areas promoting Phoenix reclinata. The strong apparent expansion of true forest trees during wet episodes can be explained partly by enhanced pollen influx via upland streams. Pollen from exotic trees and other cultural indicators appears from the 1970s onwards, but their combined influence fails to mask the region's natural vegetation dynamics.
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Aliku, OrevaOghene, and Suarau Odutola Oshunsanya. "Modelling Irrigation Water Requirements at Physiological Growth Stages of Okra Life Cycle Using CROPWAT Model for Derived Savannah and Humid Forest Zones of Nigeria." Agricultura Tropica et Subtropica 49, no. 1-4 (December 1, 2016): 20–29. http://dx.doi.org/10.1515/ats-2016-0003.
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Abstract Accurate quantification of irrigation water requirement at different physiological growth stages of okra (Abelmoschus esculentus L.) life cycle is important to prevent over or under irrigation. Field experiments were therefore initiated to model okra irrigation water requirements at the four physiological growth stages of okra life cycle using CROPWAT model. Derived savannah 1 (DS1), derived savannah 2 (DS2) and humid forest (HF) occupying 493.36 ha, 69.83 ha and 305.25 ha respectively were used. Some selected soil physical properties coupled with weather parameters were used to develop irrigation water requirements for okra crop. In DS1, the estimated crop co-efficient (Kc) values were 0.30, 0.52, 0.84 and 0.70 for the germination, crop growth, flowering and fruiting stages, respectively. Corresponding Kc values in DS2 were 0.30, 0.54, 0.90 and 0.84 and in the HF were 0.30, 0.56, 0.87 and 0.86 respectively. Daily crop evapo-transpiration values ranged from 1.16 to 3.36, 1.17 to 3.64, and 1.2 to 3.38 mm day-1 for DS1, DS2 and HF respectively with significant (p = 0.05) peak at the flowering stage for the three locations. Sustainable okra cultivation would require maximum daily irrigation water at flowering stage (reproductive phase) to meet the crop physiological needs and evapo-transpiration demand of the atmosphere.
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Rivas, Carlos A., Rafael M. Navarro-Cerillo, Jon C. Johnston, and José Guerrero-Casado. "Dry forest is more threatened but less protected than evergreen forest in Ecuador’s coastal region." Environmental Conservation 47, no. 2 (March 2, 2020): 79–83. http://dx.doi.org/10.1017/s0376892920000077.
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SummaryThe Ecuadorian coast has two main types of forests, which are differentiated by their phenology: dry forests are deciduous and more humid forests are evergreen. Less of the dry forests on the Ecuadorian coast is protected (13% of its area) than the evergreen forests (28%), and the area devoted to the protection of dry forests (1069 km2) is substantially less than the area devoted to the protection of evergreen forests (2800 km2). Yet the conservation status of dry forests is more critical, with 83% of their area classified as having very low connectivity, 70% as being highly fragile and 86% as being highly threatened. In addition, the dry forests have fewer protected areas than the evergreen forests. It is therefore necessary to increase the protection of deciduous ecosystems as part of a comprehensive national strategy because they support high levels of biodiversity and many endemic species.
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Friedel, Jürgen K., Otto Ehrmann, Michael Pfeffer, Michael Stemmer, Tobias Vollmer, and Michael Sommer. "Soil microbial biomass and activity: the effect of site characteristics in humid temperate forest ecosystems." Journal of Plant Nutrition and Soil Science 169, no. 2 (April 2006): 175–84. http://dx.doi.org/10.1002/jpln.200521763.
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Catari, Gusman, and Carlos Rivera. "Soil carbon stocks of inceptisols under different land use in the Northern tropical humid region of Honduras." Plants and Environment 3, no. 2 (June 30, 2021): 52–61. http://dx.doi.org/10.22271/2582-3744.2021.jun.52.
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Soil organic carbon (SOC) is important in the carbon cycle and studies in the field are gaining relevance because of its relation to global climate change. In this paper, we report a study of SOC stock (0-200 cm) from a 50 years old secondary forest and a pasture under inceptisols in a floodplain in the tropical humid Caribbean coast of Honduras. Samples were collected at the depths 0-20, 20-40, 40-80, 80-120, 120-160, and 160-200 cm. Total SOC stocks were 89.2±10.9 Mg ha−1, and 72.5±10.0 Mg ha−1 for the secondary forest and pasture respectively. The estimated annual increase of SOC stock in the forest is 0.34 Mg C ha-1 year-1. SOC stock values were 50.3% and 47.9% of the total (0-200 cm) in the 0-20 cm layer for forest and pasture respectively. SOC distribution at a depth of 0-20 cm were 21.26 g kg-1 and 12.09 g kg-1 for forest and pasture respectively. Soil texture at the 0-20 cm depth were clay loam, and sandy clay loam, in the forest and pasture respectively. SOC stock in these ecosystems would be reduced if they were converted back to conventional agriculture, particularly in the forest. The forest had higher SOC values because of higher litter input as compared to the pasture, particularly in the upper soil layers, at deeper layers there are no significant differences (p <0.05) and SOC values are low. Compared to most other studies in tropical regions, SOC stock in our study were lower in both ecosystems, this may be due to high precipitation (ca. 3200 mm year-1) and high temperatures, rate of decomposition of litter input, general low clay content, and possibly priming effects which we have not addressed. More studies on the SOC stock in Central America with a similar climate are needed to improve our understanding of SOC dynamics and help reducing uncertainty in SOC models.
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Coyne, Daniel L., Richard A. Plowright, Joe Twumasi, and David J. Hunt. "Prevalence of plant parasitic nematodes associated with rice in Ghana with a discussion of their importance." Nematology 1, no. 4 (1999): 399–405. http://dx.doi.org/10.1163/156854199508405.
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Abstract A survey of plant parasitic nematodes of rice was made in Ghana between 1994-1997. Fifty-one species in 29 genera were found in 145 fields from upland, hydromorphic, rainfed lowland and irrigated lowland ecosystems in the savannah and forest agroecological zones. Eighteen species were endoparasites of roots. In upland/hydromorphic rice fields in the savannah zone Pratylenchus spp. (80% of fields) and an undescribed species of Ditylenchus (78%) were most prevalent, whilst Coslenchus franklinae (84%) and Helicotylenchus spp. (76%) were most prevalent in the forest zone fields. Maximum population densities encountered were 960 C. franklinae per 100 ml soil and 700 Ditylenchus n. sp. per g root. In the savannah zone Hirschmanniella spp. (100%) were more prevalent than other nematodes in lowland rice, but in the forest zone Xiphinema bergeri (71%) was the most prevalent nematode in lowland rice. Occurrence of nematode species was different in different agroecological zones and rice ecosystems. There was no relationship between rice plant height and nematode population densities in crops close to harvest time in upland/hydromorphic fields in the savannah zone. Predominance des nematodes phytoparasites sur le riz au Ghana et discussion sur leur importance - Une prospection concernant les nematodes associes au riz a ete effectuee au Ghana de 1994 a 1997. Cinquante-et-une especes appartenant a 29 genres ont ete trouvees dans 145 rizieres de plateau, de bas-fonds, pluviales ou irriguees, tant en savane que dans des zones agroecologiques forestieres. Dix-huit especes sont des endoparasites racinaires. Dans les rizieres de plateau ou de bas-fonds en zone de savane Pratylenchus spp. (80% des rizieres) et une espece non encore decrite de Ditylenchus (78%) sont les plus abondants, tandis que Coslenchus franklinae (84%) et Helicotylenchus spp. (78%) le sont dans les rizieres de zone forestiere. Les densites maximales de population observees concernent C. franklinae (960 per 100 cm3 de sol) et Ditylenchus n. sp. (700 per 1 g de racines). Hirschmanniella spp. etaient plus abondants (100 %) que les autres nematodes dans les rizieres de bas-fonds de savane, tandis c'etait Xiphinema bergeri (71%) dans ce meme type de rizieres en zones forestieres. La presence des differentes especes de nematodes varie suivant la zone agroecologique et l'ecosysteme de la riziere. Il n'y a pas de relation entre la hauteur des plants de riz et la densite des populations de nematodes pour des cultures proches de la recolte dans les rizieres de plateau ou de bas-fonds situees en savane.
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Muñoz, David, Jordan Cissell, and Hamed Moftakhari. "Adjusting Emergent Herbaceous Wetland Elevation with Object-Based Image Analysis, Random Forest and the 2016 NLCD." Remote Sensing 11, no. 20 (October 10, 2019): 2346. http://dx.doi.org/10.3390/rs11202346.
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Emergent herbaceous wetlands are characterized by complex salt marsh ecosystems that play a key role in diverse coastal processes including carbon storage, nutrient cycling, flood attenuation and shoreline protection. Surface elevation characterization and spatiotemporal distribution of these ecosystems are commonly obtained from LiDAR measurements as this low-cost airborne technique has a wide range of applicability and usefulness in coastal environments. LiDAR techniques, despite significant advantages, show poor performance in generation of digital elevation models (DEMs) in tidal salt marshes due to large vertical errors. In this study, we present a methodology to (i) update emergent herbaceous wetlands (i.e., the ones delineated in the 2016 National Land Cover Database) to present-day conditions; and (ii) automate salt marsh elevation correction in estuarine systems. We integrate object-based image analysis and random forest technique with surface reflectance Landsat imagery to map three emergent U.S. wetlands in Weeks Bay, Alabama, Savannah Estuary, Georgia and Fire Island, New York. Conducting a hyperparameter tuning of random forest and following a hierarchical approach with three nomenclature levels for land cover classification, we are able to better map wetlands and improve overall accuracies in Weeks Bay (0.91), Savannah Estuary (0.97) and Fire Island (0.95). We then develop a tool in ArcGIS to automate salt marsh elevation correction. We use this ‘DEM-correction’ tool to modify an existing DEM (model input) with the calculated elevation correction over salt marsh regions. Our method and tool are validated with real-time kinematic elevation data and helps correct overestimated salt marsh elevation up to 0.50 m in the studied estuaries. The proposed tool can be easily adapted to different vegetation species in wetlands, and thus help provide accurate DEMs for flood inundation mapping in estuarine systems.
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Kolesnikov, Sergey, Anna Kuzina, Tatiana Minnikova, Tigran Ter-Misyakyants, Elena Nevedomaya, Yulia Akimenko, Dmitry Trufanov, et al. "Biodiagnostics of Resistance to the Copper (Cu) Pollution of Forest Soils at the Dry and Humid Subtropics in the Greater Caucasus Region." Forests 13, no. 10 (October 18, 2022): 1720. http://dx.doi.org/10.3390/f13101720.
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Forest ecosystems perform important forestry and ecological functions. However, mining and processing companies cause significant soil contamination by heavy metals, in particular, copper (Cu). The resistance of nine types and subtypes of forest soils of the dry and humid subtropics in the Greater Caucasus region to Cu contamination at concentrations of 100, 1000, and 10,000 mg/kg was evaluated for the first time following the most sensitive and informative biological (microbiological, biochemical, and phytotoxic) indicators via a laboratory simulation study. Contamination was simulated under laboratory conditions. The series of forest soils was established following their resistance to Cu pollution: brown leached soils (Haplic Cambisols Eutric) = brown typical soils (Haplic Cambisols Eutric) > brown carbonate soils (Haplic Cambisols Eutric) = sod-carbonate typical soils (Rendzic Leptosols Eutric) ≥ yellow soils (Albic Luvisols Abruptic) ≥ leached sod-carbonate soils (Rendzic Leptosols Eutric) > brown forest slightly unsaturated soils (Haplic Cambisols Eutric) > acid brown forest soils (Haplic Cambisols Eutric) > acid brown forest podzolized soils (Haplic Cambisols Eutric). Regional environmentally safe standards for the Cu content in forest soils of the dry and humid subtropics of the Greater Caucasus were proposed: for brown typical soils, brown leached soils, brown carbonate soils, brown forest slightly unsaturated soils, sod-carbonate typical soils, leached sod-carbonate soils, and yellow soils, the rMPC was 100 mg/kg; for acid brown forest soils and acid brown forest podzolized soils, the rMPC was 70 mg/kg.
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Lin, Yang, Avner Gross, Christine S. O'Connell, and Whendee L. Silver. "Anoxic conditions maintained high phosphorus sorption in humid tropical forest soils." Biogeosciences 17, no. 1 (January 7, 2020): 89–101. http://dx.doi.org/10.5194/bg-17-89-2020.
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Abstract. The strong phosphorus (P) sorption capacity of iron (Fe) and aluminum (Al) minerals in highly weathered, acidic soils of humid tropical forests is generally assumed to be an important driver of P limitation to plants and microbial activity in these ecosystems. Humid tropical forest soils often experience fluctuating redox conditions that reduce Fe and raise pH. It is commonly thought that Fe reduction generally decreases the capacity and strength of P sorption. Here we examined the effects of 14 d oxic and anoxic incubations on soil P sorption dynamics in humid tropical forest soils from Puerto Rico. Contrary to the conventional belief, soil P sorption capacity did not decrease under anoxic conditions, suggesting that soil minerals remain strong P sinks even under reducing conditions. Sorption of P occurred very rapidly in these soils, with at least 60 % of the added P disappearing from the solution within 6 h. Estimated P sorption capacities were much higher, often by an order of magnitude, than the soil total P contents. However, the strength of P sorption under reducing conditions was weaker, as indicated by the increased solubility of sorbed P in NaHCO3 solution. Our results show that highly weathered soil minerals can retain P even under anoxic conditions, where it might otherwise be susceptible to leaching. Anoxic events can also potentially increase P bioavailability by decreasing the strength, rather than the capacity, of P sorption. These results improve our understanding of the redox effects on biogeochemical cycling in tropical forests.
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Akodéwou, Amah, and Michel Godron. "Agricultural Land-Use Increases Floral Species Richness in Tropical Dry Forest and Savannah Ecosystems in West Africa." Diversity 14, no. 2 (February 1, 2022): 106. http://dx.doi.org/10.3390/d14020106.
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The diversity and structure of plant communities are valuable indicators for assessing landscape quality. Land-use change is one of the main factors considered to affect and have the strongest impacts on biodiversity. In this study, we assessed the effects of the conversion of tropical dry forests and savannahs into agricultural lands on the floral diversity and the structure of the vegetation. For this purpose, we carried out vegetation surveys in 198 plots of 50 m × 50 m. Within each plot, we documented all herbaceous, shrubby, and tree species present. We calculated total, spatial, and local floral diversities by land-use types and characterized the structure of the plant communities. Our results show that the overall floral diversity of the study area remains quite high (483 species of vascular plants from 298 genera and 71 families) and was not strongly impacted by agricultural land use (Pareto inequality index is 23–77). Croplands had the highest spatial (9.4) and local diversities. There was no significant difference between the land-use types in terms of the native species richness while croplands harbored significantly the most alien species. Agricultural land use significantly affected the structure of the plant communities. Trees are very rare in croplands and are frequent in forests and savannahs. The clearing of Guinean dry forests and savannahs for cropping did not automatically lead to a loss of some aspects of ordinary floral diversity. For a better understanding of the effects of land-use change on biodiversity, it would then be more suitable to specify in the studies whether the species concerned are native, alien, generalist, or specialist.
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Schyra, Janine, Jean Norbert B. K. Gbenyedji, and Judith Korb. "A comparison of termite assemblages from West African savannah and forest ecosystems using morphological and molecular markers." PLOS ONE 14, no. 6 (June 5, 2019): e0216986. http://dx.doi.org/10.1371/journal.pone.0216986.
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Ranaivoson, Tahiry, Bakolimalala Rakouth, Andreas Buerkert, and Katja Brinkmann. "Wood biomass availability for smallholder charcoal production in dry forest and savannah ecosystems of south-western Madagascar." Journal of Arid Environments 146 (November 2017): 86–94. http://dx.doi.org/10.1016/j.jaridenv.2017.07.002.
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Bhadauria, Tuneera, and P. S. Ramakrishnan. "Population dynamics of earthworms and their activity in forest ecosystems of North-east India." Journal of Tropical Ecology 7, no. 3 (August 1991): 305–18. http://dx.doi.org/10.1017/s0266467400005575.
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ABSTRACTA comparative analysis of earthworm populations in seral Khasi pine forest represented byPinus kesiya5- and 35-year old stands, and a climax broad-leaved mixed forest represented by a sacred grove was done at altitudes of 1500 m in Meghalaya in north-east India.Tonoscolax horaiioccurred under all forest types whereasAmynthas diffringensandEulyphoeus feslivuswere confined to pine forest stands only.Perionyxsp. andDrawida assamensiswere restricted to the sacred grove.T. horaiihad larger numbers in all three different forest types. This species offers possibilities of vermicullurc for biologically improving soil fertility in manmade ecosystems because of its wide range of tolerance.Generally earthworm populations were more active during the monsoon season;A. diffringenswas however, more active during the winter, thereby conferring an advantage on this species as it was enabled to avoid competition during the monsoon season when other species dominate. Earthworm activity was generally higher in the sacred grove than in the pine forest stands. Population size was significantly correlated with soil moisture, temperature and pH. Wormcasts had a higher pH and nutrient status than the soil.In the highly leached soils of the humid tropics where there is a large concentration of fine root biomass in the surface soil layers, earthworm activity is beneficial because it helps incorporate detritus into the mineral soil rapidly and locally concentrates nutrients in the surface layers.
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Ssemmanda, I., V. Gelorini, and D. Verschuren. "Sensitivity of East African savannah vegetation to historical moisture-balance variation." Climate of the Past 10, no. 6 (November 28, 2014): 2067–80. http://dx.doi.org/10.5194/cp-10-2067-2014.
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Abstract. Fossil pollen records provide key insight into the sensitivity of terrestrial ecosystems to climate change. However, tracing vegetation response to relatively modest historical climate fluctuations is often complicated by the overriding signature of anthropogenic landscape disturbance. Here we use high-resolution pollen data from a ~200-year lake-sediment record in open wooded savannah of Queen Elizabeth National Park (southwestern Uganda) to assess the sensitivity of the tropical lowland grassland–forest transition to historical, decade-scale moisture-balance fluctuations. Specifically we trace vegetation response to three episodes of higher average rainfall dated to the 1820s–1830s, ca. 1865–1890 and from 1962 to around 2000. Our pollen data indeed reveal a sequence of three wet periods, separated by two drier periods. During the inferred wetter episodes we find increases in the percent pollen abundance of trees and shrubs from moist semi-deciduous forest (Allophylus, Macaranga, Alchornea, Celtis), riparian forest (Phoenix reclinata) and wooded savannah (Acalypha, Rhus-type vulgaris, Combretaceae/Melastomataceae) as well as taxa common in the local rift-valley grasslands (Acacia, Ficus), together creating strong temporary reductions in Poaceae pollen (to 45–55% of the terrestrial pollen sum). During intervening dry periods, Poaceae pollen attained values of 65–75%, and dryland herbs such as Commelina, Justicia-type odora and Chenopodiaceae expanded at the expense of Asteraceae, Solanum-type, Swertia usambarensis-type, and (modestly so) Urticaceae. Noting that the overall richness of arboreal taxa remained high but their combined abundance low, we conclude that the landscape surrounding Lake Chibwera has been an open wooded savannah throughout the past 200 years, with historical moisture-balance variation exerting modest effects on local tree cover (mostly the abundance of Acacia and Ficus) and the occurrence of damp soil areas promoting Phoenix reclinata. The strong apparent expansion of true forest trees during wet episodes can be explained partly by enhanced pollen input via a temporarily activated upland stream. Pollen from exotic trees and cultural indicators appears from the 1970s onwards, but their combined influence fails to mask the signature of natural vegetation dynamics in the pollen record.
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Zhang, Zhong‐Chun, Zheng‐Ke Li, Yan‐Chao Yin, Yaqiong Li, Yu Jia, Min Chen, and Bao‐Sheng Qiu. "Widespread occurrence and unexpected diversity of red‐shifted chlorophyll producing cyanobacteria in humid subtropical forest ecosystems." Environmental Microbiology 21, no. 4 (March 21, 2019): 1497–510. http://dx.doi.org/10.1111/1462-2920.14582.
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Dupont, L. M., H. Behling, and J. H. Kim. "Thirty thousand years of vegetation development and climate change in Angola (Ocean Drilling Program Site 1078)." Climate of the Past 4, no. 2 (June 10, 2008): 107–24. http://dx.doi.org/10.5194/cp-4-107-2008.
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Abstract. ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development during full glacial, deglacial, and interglacial conditions. During the glacial the vegetation in Angola was very open consisting of grass and heath lands, deserts and semi-deserts, which suggests a cool and dry climate. A change to warmer and more humid conditions is indicated by forest expansion starting in step with the earliest temperature rise in Antarctica, 22 thousand years ago. We infer that around the period of Heinrich Event 1, a northward excursion of the Angola Benguela Front and the Congo Air Boundary resulted in cool sea surface temperatures but rain forest remained present in the northern lowlands of Angola. Rain forest and dry forest area increase 15 thousand years ago. During the Holocene, dry forests and Miombo woodlands expanded. Also in Angola globally recognised climate changes at 8 thousand and 4 thousand years ago had an impact on the vegetation. During the past 2 thousand years, savannah vegetation became dominant.
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Castaldi, S., T. Bertolini, A. Valente, T. Chiti, and R. Valentini. "Nitrous oxide emissions from soil of an African rain forest in Ghana." Biogeosciences Discussions 9, no. 11 (November 20, 2012): 16565–88. http://dx.doi.org/10.5194/bgd-9-16565-2012.
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Abstract. Most recently atmospheric studies have evidenced the imprint of large N2O sources in tropical/subtropical lands. This source might be attributed to agricultural areas as well as to natural humid ecosystems. The uncertainty related to both sources is very high, due to the paucity of data and small frequency of sampling in tropical studies. This is particularly relevant for the African continent. The principal objective of this work was to quantify the annual budget of N2O emissions in an African tropical rain forest. Soil N2O emissions were measured over 19 months in Ghana, National Park of Ankasa, in upland and lowland areas, for a total of 119 days of observation. The calculated annual average emission was 2.33 ± 0.20 kg N-N2O ha−1yr−1, taking into account the proportion of upland vs. lowland, as the two areas showed significantly different fluxes, the lowland being characterized by lower N2O emissions. N2O fluxes peaked between June and August and were significantly correlated with soil respiration on a daily and monthly basis. No clear correlation was found in the upland areas between N2O fluxes and soil water content or rain whereas in the lowland soil water content concurred with soil respiration in determining N2O flux variability. The N2O source strength calculated in this study, very close to those reported for the other two available studies in African rain forests and to the estimated mean derived from worldwide studies in humid tropical forests (2.96 ± 2.0 kg N-N2O ha−1 yr−1), supports the concept that tropical humid forests represent the strongest natural source of N2O emissions, most probably the strongest source of N2O in the African continent.
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Stojanović, Dejan, Saša Orlović, Milica Zlatković, Saša Kostić, Verica Vasić, Boban Miletić, Lazar Kesić, et al. "Climate change within Serbian forests: Current state and future perspectives." Topola, no. 208 (2021): 39–56. http://dx.doi.org/10.5937/topola2108039s.
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Extreme weather conditions, namely droughts, heat waves, heavy rains, floods, and landslides are becoming more frequent globally and in Serbia as a result of climate change. Generally, various parts of human society are affected by changing climate conditions. Forest ecosystems are one of the most sensitive systems to weather and climate. In that sense, small changes may lead to large disturbances including forest decline, outbreaks of insect pests and diseases and eventually mortality. In Serbia, the average temperature in forest ecosystems of the most important and abundant forest tree species has risen for more than 1°C in the last thirty years (1990-2019) in comparison to the previous period (1961-1990). During the last thirty years, the northern and western parts of Serbia experienced an increase in precipitation as opposed to the southern and eastern parts of the country. If one takes a closer look at the climate within a particular forest stands, it would seem that the effect of precipitation decrease is stronger in less humid parts of a tree species range. In this paper, we discuss various aspects of climate change impacts on forests and forestry, including forest ecology, genetics, physiology, pests and diseases, ground vegetation, monitoring, reporting and verification system, climate change litigation and perspectives of forests in the 21st century in Serbia.
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Ghosh, Subhasis, Subhajit Bandopadhyay, and Dany A. Cotrina Sánchez. "Long-Term Sensitivity Analysis of Palmer Drought Severity Index (PDSI) through Uncertainty and Error Estimation from Plant Productivity and Biophysical Parameters." Environmental Sciences Proceedings 3, no. 1 (November 12, 2020): 57. http://dx.doi.org/10.3390/iecf2020-07956.
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Palmer Drought Severity Index (PDSI) is the most effective and well-acknowledged drought severity index that particularly determines the long-term drought conditions over the forest and other terrestrial ecosystems. However, the sensitivity of PDSI has not been explored yet based on productivity (i.e., Gross Primary Productivity (GPP)), biophysical parameters (i.e., biomass—Leaf Area Index (LAI) and Enhanced Vegetation Index (EVI) and greenness content—Normalized Difference Vegetation Index (NDVI)), and absorbed solar radiation by plants (i.e., fraction of Absorbed Solar Radiation (fAPAR)) over a humid-subtropical forest ecosystem. In this study, the sensitivity of the PDSI was analyzed through uncertainty and error estimation modeling from long-term (2015–2019) MODIS GPP and reflectance data using Google Earth Engine (GEE) over a humid-subtropical forest region of Arunachal Pradesh, India. It was experimentally observed that EVI was the most sensitive parameter to the PDSI in long-run observation based on a low uncertainty (2.39–3.01%) and error (0.07–0.12) compared to the other parameters. Besides, EVI had a strong agreement with PDSI compared to GPP, NDVI, LAI, and fAPAR, where the Pearson’s r ranged from −0.87 to −0.63, except 2015. Hence, it is stated that EVI is the simple, effective, and most complementary indicator for assessing the PDSI over the forest regions of a tropical ecosystem. This study showed that EVI might be a promising tool for effectively evaluating long-term drought impacts on the forest ecosystem that indicates the actual water deficit-induced stress conditions.