Lowland Areas Research Articles

Tracking states and transitions in semiarid rangelands: A spatiotemporal archetypal analysis of productivity dynamics using wavelets

Climate change poses challenges in classifying ecosystem dynamics, as they are influenced by shifting dynamics resulting from changes in climate forces and meteorological variables, including temperature and water availability. To address this, our study presents a novel approach using Continuous Wavelet Transform (CWT) and power spectrum analysis to classify vegetation dynamics, considering the time-dependent variability of ecosystem frequencies. We applied our method to centred and standardized MODIS NDVI time series for the period 2000–2021, using an experimental field station in northern Patagonia as a case study. By performing a continuous wavelet transform on the data for each pixel, we obtained instantaneous power spectra, capturing variability across different dates and pixels. These spectrums were then consolidated into a comprehensive database, and subsequently classified using archetypal analysis. We identified a convex combination of archetypal spectrums that best represented the entire power spectrum database. Mapping the resulting archetypes and their weights in both space and time allowed us to explore pixels' variations in archetype weights in relation to factors such as time, topography, and climate. In addition, to examine the potential relationship between the NDVI time series and climate drivers, we computed the Average Cross-Wavelet Power Spectrum (ACWPS) to different climatic indices. Three archetypes were sufficient to explain the majority of power spectrum variability in the study area. These archetypes exhibited distinctive characteristics: 1) medium-frequency variability (2–4 years), 2) low-frequency variability (>4 years), and 3) an annual (i.e. seasonal) cycle with low-frequency variability. Spatially, the first two archetypes were predominantly observed in highland steppes, while the third archetype prevailed in lowland areas associated with meadows. At the beginning of the studied period, Archetypes 1 and 3 dominated, but after the Puyehue-Cordón Caulle Volcanic Complex eruption in 2011 their prominence diminished, and Archetype 2 became more prevalent in the whole study area. Finally, all three NDVI series representative of archetypes showed a relative peak at approximately four years, which could be linked to the Indian Ocean Dipole variability. These results highlight an abrupt shift in the system's behaviour, primarily related to changes in variability distribution rather than mean values. This disturbance-induced transition aligns with the theory of state and transitions in ecological system dynamics. We propose that the states in this model are not fixed but represent alternative dynamic behaviours, akin to different types of limit cycles. Consequently, employing a wavelet analysis-based classification method provides a robust means of studying and understanding such variability and transitions, thereby offering clarity and comprehension of ecosystem states. Notably, this methodology proves particularly effective for large databases of detailed time series.

A review of grass species yields and growth rates in Northland, New Zealand

ABSTRACT Pastoral farming is a major land use in New Zealand's Northland region, with 3,171 farm holdings and a total area of 637,500 hectares in 2022. The region's pasture grasses include temperate (C3) and subtropical and tropical (C4) grasses which support dairy, and sheep and beef production from grazing. In lowland areas, C3 and some annual C4 grasses are prevalent where cultivation occurs, while perennial C4 grasses dominate areas with low soil fertility and summer dry conditions. Grass-based pasture growth rates (kg dry matter/ha/day) from published and unpublished sources were assembled into the AgYields database. Among the resident and sown grasses tested in Kaitaia, Kaikohe, Whangarei and Dargaville, perennial ryegrass represented ∼60% of the total data points. Dominant kikuyu pastures represented 23% and the remaining species represented 17%. Rates of growth ranged from 5 to 120 kg DM/ha/day, being lowest in late autumn-winter and highest in early summer. Data were compared and agronomic traits (i.e. drought tolerance, biomass production and tillering) are discussed to assess species suitability for the Northland environment. The medium-term prospect suggests an urgent need to improve research into management of cocksfoot and tall fescue-based pastures to provide viable alternatives to overcome the decreasing persistence of perennial ryegrass.

Free-range poultry farming in a lowland suburban area increased the health risk of heavy metal contamination

Free-range poultry farming in a lowland suburban area increased the health risk of heavy metal contamination

Impacts of riverbed aggradation on groundwater regime in a lowland area

Abstract In this study, the influence of riverbed silting on the groundwater regime in a lowland area was investigated. The study area is situated at the Rye Island (Žitný Ostrov) in Slovakia, along the Gabčíkovo – Topoľníky canal, which is part of the drainage-irrigation canal system constructed in this locality. The Rye Island is an area with very low slope (0.25 10–4) and good climatic conditions for aquatic vegetation, therefore the canals are influenced by intensive silting processes. The spatial and temporal patterns of surface water – groundwater exchange are significantly influenced by the thickness of riverbed sediments and their permeability. The aim of this study was to evaluate the thickness and hydraulic conductivity of bed sediments in the Gabčíkovo – Topoľníky canal and to examine their influence on the groundwater – surface water interaction in the area. The hydraulic conductivity of the sediments was assessed from undisturbed samples by the falling head method. The obtained data were used for numerical simulations of groundwater heads by the TRIWACO model for different drainage and infiltration resistance conditions in the area of interest. The results of this study can support the planning of canal maintenance.

Enhancing Coastal Flooding Preparedness To Climate Change: An Experimental Analysis Of Urban-Integrated Non-Conventional Adaptation Solutions

Coastal areas are particularly vulnerable to climate change due to their exposure to mean sea-level rise and an intensification in the frequency and intensity of extreme events. Among the most vulnerable areas in Europe are the coastal urban areas of the Macaronesia Islands territories, since they are characterized with urban settlements in low land areas, being highly exposed to flooding. Within the scope of sustainable development and at the same time with the aim of increasing resilience in these areas, the development of a new methodological framework for implementing risk reduction and adaptation measures in coastal flood-prone areas is being applied with the framework of the LIFE-Garachico project (Tenerife, Spain). One of proposed adaptation options is the implementation of concrete blocks in the form of a bench to be disposed along the municipality seafront with the aim of reducing the impact of water sheets into building, generated by wave overtopping. This study presents the results obtained by means of a hybrid numerical and experimental technique to define the hydraulic performance of different bench configuration. Results are included in a global methodology to define the optimum time to implement this solution due to the consideration of different climate change scenarios.

Characteristics and classification of the peat at Toba Highland, North Sumatera, Indonesia

Peatland serves as a crucial natural resource with hydrological and other environmental functions essential for all living organisms. In some regions, peat soil isn't limited to lowland areas, it is also found in highland areas. This study is a survey research aiming to examine the characteristics of the highland peatlands of Toba North Sumatera, namely in the Village of Matiti II, Humbang Hasundutan Regency, North Sumatera and lowland peatlands as control of peatlands in general in Sidomulyo Village, Bilah Hilir Subdistrict, Labuhan Batu. The study employed a survey research approach with a descriptive method to determine the differences in the characteristics of highland Toba peat soils. In each area, a representative profile was made, and the soil morphology, characteristics and classification were observed according to the 2014 soil taxonomic classification. Soil samples were taken from each layer in the soil profile for soil analysis in the laboratory. Soil analysis included bulk density, pH H₂O, pH NaF, CEC, base saturation, organic C, total N, C/N, electrical conductivity (EC) and ash content. The results showed that the difference in altitude directly affected the microclimate and the hydrologic conditions, which in turn affected the characteristics of the peat soil. In the context of the Toba highland, the main source of peat soils comes from rainfall. In contrast with the peatland of the lowlands, where the impact of tides is a significant factor, the peat of the Toba highland is affected by the surrounding hills.

Growth and yield response of Tanjung II and Unpad CB2 red chili varieties grown in the medium land

Red chili is an important commodity that is daily needed by the community. Non-central chili areas often experience deficits due to the high consumption volume and low productivity of chili peppers. To increase the productivity of chili in non-central areas, expand it in the medium land. This study aims to determine the productivity of two introduced chili varieties in the medium land whose adaptation areas came from lowland and highland areas. This study was analyzed using an independent sample T-test at a significant level of 5%. The results of the data analysis showed that the Tanjung II variety significantly influenced the parameters of stem diameter and weight of the fruit. Meanwhile, the Unpad CB2 variety significantly influences the parameters of plant height, number of leaves, number of flowers, number of fruits, and fruit set. However, both varieties have no noticeable effect on the weight parameters of the cropping fruit and potential yield in hectares. The Tanjung II variety experienced a decrease in yield by 54.58%, while the Unpad CB2 variety was 53.56%.

Comparison of Surface Ozone Variability in Mountainous Forest Areas and Lowland Urban Areas in Southeast China

The ozone (O3) variations in southeast China are largely different between mountainous forest areas located inland, and lowland urban areas located near the coast. Here, we selected these two kinds of areas to compare their similarities and differences in surface O3 variability from diurnal to seasonal scales. Our results show that in comparison with the lowland urban areas (coastal areas), the mountainous forest areas (inland areas) are characterized with less human activates, lower precursor emissions, wetter and colder meteorological conditions, and denser vegetation covers. This can lead to lower chemical O3 production and higher O3 deposition rates in the inland areas. The annual mean of 8-h O3 maximum concentrations (MDA8 O3) in the inland areas are ~15 μg·m−3 (i.e. ~15%) lower than that in the coastal areas. The day-to-day variation in surface O3 in the two types of the areas is rather similar, with a correlation coefficient of 0.75 between them, suggesting similar influences on large scales, such as weather patterns, regional O3 transport, and background O3. Over 2016–2020, O3 concentrations in all the areas shows a trend of “rising and then falling”, with a peak in 2017 and 2018. Daily MDA8 O3 correlates with solar radiation most in the coastal areas, while in the inland areas, it is correlated with relative humidity most. Diurnally, during the morning, O3 concentrations in the inland areas increase faster than in the coastal areas in most seasons, mainly due to a faster increase in temperature and decrease in humidity. While in the evening, O3 concentrations decrease faster in the inland areas than in the coastal areas, mostly attributable to a higher titration effect in the inland areas. Seasonally, both areas share a double-peak variation in O3 concentrations, with two peaks in spring and autumn and two valleys in summer and winter. We found that the valley in summer is related to the summer Asian monsoon that induces large-scale convections bringing local O3 upward but blocking inflow of O3 downward, while the one in winter is due to low O3 production. The coastal areas experienced more exceedance days (~30 days per year) than inland areas (~5-10 days per year), with O3 sources largely from the northeast. Overall, the similarities and differences in O3 concentrations between inland and coastal areas in southeastern China are rather unique, reflecting the collective impact of geographic-related meteorology, O3 precursor emissions, and vegetation on surface O3 concentrations.

Indigenous Goat Populations in Northwestern and Western Zones of Tigray Region, Ethiopia: Characterization of Major Husbandry Practices and Kidding Patterns

The survey was conducted before the war (before October 2020) in Tigray Region, Ethiopia. Goats are highly concentrated in the lowland areas than in the highlands of Ethiopia. Sample households of Begait (102), Hassan (106) and Arado (181) goats were randomly involved in the face-to-face interview. Statistical Package for Social Sciences software was used for data analysis. Illiterate respondents were in Begait (42%), Hassan (29%) and Arado (55%). Cattle and goats were the major economic sources in Begait (10.19±9.1 Tropical Livestock Unit (TLU), 4.30±2.8 TLU) and Arado (4.77±3.2 TLU, 1.27±0.9 TLU) respondents. The mean flock size of Arado goat population (12.65±9.9) was significantly (P<0.005) lower than the mean flock sizes of Begait (43.02±28.1) and Hassan (70.29±52.6) populations. Animals went to water source in most respondents (100.0% of Begait, 67.0% of Hassan and 87% of Arado), and river was the major water source for the animals of about 47% of Begait, 43% of Hassan and 79.0% of Arado respondents. Animals of about 56% of Hassan and 57% of Arado respondents travelled a distance of 1-5 Kilometer (Km) to obtain water, and dry season daily watering frequency of once a day was dominantly practiced in about 88% of Begait and 83% of Hassan respondents. Diseases and external parasites were reported in Begait (96%, 85%), Hassan (98%, 90%) and Arado (67%, 87%) respondents which affected indigenous goat productivity. There was no access to veterinary service centers (VSCs) in about 47% of Begait, 65% of Hassan and 93% of Arado respondents, and some respondents in about 24% of Begait and 17% of Hassan travelled a distance of greater than 10 Km to reach VSCs. Own buck use for mating and buck birth in own flocks were exhibited in Begait (93%, 85%), Hassan (95%, 76%) and Arado (38%, 35%) respondents, respectively. Uncontrolled mating and buck use outside of own flock were practiced in Begait (70%, 73%), Hassan (43%, 65%) and Arado (100.0%, 100.0%) respondents due to most goats graze in communal lands, respectively. Unknown buck to does ratio was practiced in 41% of Begait and 39% of Hassan respondents. Unknown buck to does ratio and a ratio of one buck to all does in the flock were practiced in Arado (8%, 67%) respondents, respectively, and crossbreeding was highly practiced in Begait respondents (41%). The dominant kidding months of Begait and Arado goat populations were in September up to November whilst that of Hassan goat population were in October up to December. Castration and traditional castration method were practiced in Begait (54%, 54%), Hassan (39%, 37%) and Arado (70%, 64%) respondents, respectively. Community education, access to water, access to VSC, buck to doe ratio, kidding pattern improvement and castration to control inbreeding need critical attention.

Assessing the Impact of Climate Change on Snowfall Conditions in Poland Based on the Snow Fraction Sensitivity Index

This study focuses on temperature and snowfall conditions in Poland, both of which were analyzed from 1981 to 2020. A 40-year record of daily snow fraction time series values was reconstructed using a unique and global multi-source weighted-ensemble precipitation (MSWEP) product, which provided a spatially and temporally consistent reference for the assessment of meteorological conditions. The average states and trends in snow fraction and temperature were analyzed across several years, focusing on the 6-month cold season (November–April). The impact of temperature on the snow fraction pattern was assessed by introducing a snow fraction sensitivity index. To predict short-term changes in snow conditions, a proxy model was established; it incorporated historical trends in the snow fraction as well as its mean state. This study provides clear evidence that the snow fraction is principally controlled by increases in temperature. A warming climate will thus cause a decline in the snow fraction, as we observed in vast lowland areas. Given the ongoing global warming, by the 2050s, snow-dominated areas may go from covering 86% to only 30% of the country’s surface; they will be converted into transient rain–snow areas. Our results demonstrate that a decline in snow water resources has already occurred, and these resources are expected to diminish further in the near future. New insights into the sensitivity of the snow fraction to climate warming will expand our collective knowledge of the magnitude and spatial extent of snow degradation. Such widespread changes have implications for the timing and availability of soil and groundwater resources as well as the timing and likelihood of floods and droughts. Thus, these findings will provide valuable information that can inform environmental managers of the importance of changing snowfall conditions, guiding them to include this aspect in future climate adaptation strategies.

Estimating risk to prevent damage: predicting and preventing coypu (Myocastor coypus) damage to transport infrastructure.

A major impact of invasive Myocastor coypus in their introduction range is the collapse of riverbanks and nearby infrastructure, such as railway lines, due to the species' burrowing activities. Because widespread implementation of preventive measures along watercourses is unfeasible, identifying susceptible areas is key to guide targeted management actions. This study used species-habitat models to: (i) identify local environmental features of the railway line/watercourse intersections (RLWIs) that make them particularly susceptible to coypu damage, and (ii) predict species occurrence probability over a wide lowland-hilly area of northern Italy (Lombardy) to identify priority areas for monitoring. Local-scale models identified that the RLWIs most susceptible to burrowing were those surrounded by arable land with interspersed hedgerows locally characterized by high herbaceous vegetation and clay soil. In urbanized areas and areas of intensive agriculture, coypu dens were generally located significantly closer to the railway, increasing the risk of collapse. A landscape-scale species distribution model showed that lowland areas along major rivers and lake shores, and also agricultural areas with a dense minor hydrographic network, particularly in the southeast of the study area, are more likely to be occupied by coypu. Local-scale models showed that specific environmental characteristics increase the risk of burrowing near RLWIs. The landscape-scale model allowed us to predict which areas require thorough monitoring of RLWIs to search for such local characteristics to implement preventive management measures. The proposed model-based framework can be applied to any geographical context to predict and prevent coypu damage. © 2024 Society of Chemical Industry.

Blood Parasitic Diseases of Cattle in the Nakhchivan Autonomous Republic of Azerbaijan

The result of a study on the distribution of parasitosis in cattle in the Nakhichevan Autonomous Republic of Azerbaijan is presented. In a study of 422 heads of cattle, parasite carriage reached 73%. Increased infestation is observed in lowland and foothill areas. The most common species are Theileria annulata(65.6%) and Anaplasma marginale(14.9%). To combat blood-parasitic diseases in the Republic, it is necessary to determine the type of blood-parasitic diseases, study the species composition of ixodid ticks and seasonal periods of parasitism, the reasons for the spread of ticks. In conclusion, a number of practical measures for the prevention of blood parasitic diseases are proposed.

Lentil Cultivar Evaluation in Diverse Organic Mediterranean Environments

Lentil (Lens culinaris Medik.) production faces challenges due to shifting environmental conditions, potentially leading to a transition towards cooler or highland Mediterranean environments. This study assessed the responses of five lentil genotypes across five diverse locations (L1–L5) managed under organic cropping systems over two seasons, focusing on key parameters including seed yield (SY), crude protein (CP), cooking time (CT), seed loss percentage (SL), and yield loss per hectare (YL) caused by bruchid (Bruchus sp.). Excessive seasonal rainfall (500 mm), low winter temperatures (−17.9 °C), bruchid SL, and spring sowing were identified as crucial, particularly in challenging environments like highlands. Genotype selection was highlighted as essential for balancing yield and stability, with the small-seeded cultivar ‘Dimitra’ demonstrating lower YL due to bruchid. Additionally, increased CP was noted in response to heightened bruchid infestations. Specific recommendations were proposed for different environments: In productive lowland areas with low bruchid pressure and high CTs (L1), prioritizing cultivars like ‘Samos’, ‘Dimitra’, and ‘Thessalia’ enhances quality. Locations with high bruchid populations (L4) were not favored organic production but can serve as genetic resistance screening sites. High-elevation environments (L3, L5) proved significantly less productive, underscoring the requirement for earlier and winter-hardy cultivars. These insights guide lentil cultivation, emphasizing the need for tailored breeding strategies adaptable to changing environments.

Rainfall prediction for data scares areas using metrological satellites in the case of the Lake Tana sub-basin, Ethiopia

Abstract In African nations with complex topographies, alternative rainfall estimation methods such as satellites are crucial. This study is aimed at predicting the spatial and temporal distribution of rainfall in the Lake Tana sub-basin from 1990 to 2020. A satellite-based rainfall estimate of Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) was used with the same spanning period (1990–2020). The validation process employs point-to-pixel analysis, comparing CHIRPS estimates with observed data at specific gauge stations. The findings showed that CHIRPS had well-estimated rainfall incidence in the highland areas and significantly overestimated it in the lowland areas. The Mann–Kendall trends for January, June, and August indicate decreasing trends, while the Bega and spring seasons show notable declines. Regression analysis reveals a non-significant decrease in annual rainfall with the highest rainfall in the summer and relatively dry winters. In addition, the coefficient of variation value of 26.37% suggests a moderate level of variability around the mean annual rainfall. In conclusion, the CHIRPS satellite exhibited varied performance across the Tana Sub-basin, with site-specific discrepancies and notable inaccuracies at certain stations. The study underscores the importance of considering local factors and topography in satellite-based rainfall assessments, providing valuable insights for agricultural planning in the region.

ON THE HABITATION OF SOPRANO PIPISTRELLE PIPISTRELLUS PYGMAEUS (LEACH, 1825) IN THE CIS-URALS AND THE URALS

Literature data and new data on the distribution of bats of the Pipistrellus pipistrellus/pygmaeus complex in the Cis-Urals and the Urals are summarized. During the expeditionary work of 2015-2018 and 2023, the habitation of Soprano Pipistrelle P. pygmaeus was established in the Udmurt Republic, the Republic of Bashkortostan and the Orenburg region, and the search for Common Pipistrelle P. pipistrellus s. str., as well as in the adjacent territories of the Volga region, did not give a positive result. Previously cited in literary sources, information about the habitation of P. pipistrellus in the Cis-Urals and the Urals was not supported by museum copies, so they cannot be veri ed. In this regard, we believe that all indications of nds in the Cis-Urals and Urals Common Pipistrelle P. pipistrellus made by other authors should be attributed to the form P. pygmaeus. In total, we caught ten individuals of P. pygmaeus (6♀♀ad, 3♀♀ and 1♂ sad). In examined animals, morphometric indicators and external diagnostic signs turned out to be typical for the species. Soprano Pipistrelle is found in oodplain forests in lowland and low-mountain areas with heights up to 250 m above sea level. The Cis-Urals and Urals are included in the eld of breeding by females of P. pygmaeus, as evidenced by the ndings of adult females and subadalt. Adult males in the study area were not recorded. Beyond the Ural Range, the nds of P. pygmaeus are unknown, thus, the western foothills of the Urals are the eastern border of the distribution of the species. The seasonal movement routes and wintering sites are not known. In the Cis-Urals and Urals, Soprano Pipistrelle is a very rare, locally common species. To preserve populations and identify ecological features of the habitat of P. pygmaeus on the border of the range, it is advisable to conduct monitoring studies and add the species to the Red Books of the Udmurt Republic, the Republic of Bashkortostan and the Orenburg Region.

Understanding Farmers Perception of Climate Change to Prepare Adaptation of Farmers

The impact of climate change has resulted in a decline in agricultural productivity. This study estimated farmers’ perceptions of climate change by comparing Imogiri Sub-district represent highland area and Pundong Sub-district deputize lowland area farmers in Bantul Regency. This study collected data using questionnaires to 79 respondents then analysis by likerts scale and descriptive statistical. The results showed that there six indicators of climate change became farmers’ perceptions. The farmers perception on highland regarding climate change is that 54% of farmers feel a decrease in rainfall, 54% feel drought, 55.2% feel a longer dry season, 60.8% feel reduced water sources, 74.4% feel a decrease in crop quality and 73.2% feel a decrease in crop quantity. At the same time, the perception of farmers in the lowland area regarding climate change is 66.9% of farmers feel a decrease in rainfall, 68.28% feel drought, 71.03% feel a longer dry season, 68.28% feel reduced water sources, 77.93% feel a decrease in crop quality and 77.93% feel a decrease in crop quantity. The importance of farmers’ perceptions of climate change may be used to adaptation from climate change. Understanding farmers’ perceptions can aid the impact of climate change on agricultural productivity.

Update of the geographic range of Humboldt's squirrel monkeys (Saimiri cassiquiarensis cassiquiarensis Lesson, 1840) using a model-based approach.

Saimiri cassiquiarensis cassiquiarensis (Cebidae) is a primate subspecies with a wide distribution in the Amazonian region of Brazil, Colombia, and Venezuela. However, the boundaries of its geographic range remain poorly defined. This study presents new occurrence localities for this subspecies and updates its distribution using a compiled data set of 140 occurrence records based on literature, specimens vouchered in scientific collections, and new field data to produce model-based range maps. After cleaning our data set, we updated the subspecies' extent of occurrence, which was used in model calibration. We then modeled the subspecies' range using a maximum entropy algorithm (MaxEnt). The final model was adjusted using a fixed threshold, and we revised this polygon based on known geographic barriers and parapatric congeneric ranges. Our findings indicate that this subspecies is strongly associated with lowland areas, with consistently high daily temperatures. We propose modifications to all range boundaries and estimate that 3% of the area of occupancy (AOO,as defined by IUCN) has already been lost due to deforestation, resulting in a current range of 224,469 km2. We also found that 54% of their AOO is currently covered by protected areas (PAs). Based on these results, we consider that this subspecies is currently properly classified as Least Concern, because it occupies an extensive range, which is relatively well covered by PAs, and is currently experiencing low rates of deforestation.

Wetland landscapes in the Southern Maya Lowlands (Naachtun, Guatemala) from the ancient agroecosystems to the tropical biosphere reserve: Ecology, exploitation and management of water and soil resources, and heritage legacy

AbstractIn the Biosphere Reserve of the Maya Lowlands, the large‐scale characterisation of the current wetlands ecology and the exploitation and management of their natural resources by the ancient Maya is severely constrained by the forest. This paper presents an integrated geomatic, geoarchaeological and ecological approach, developed to overcome this obstacle in the microregion of the Naachtun Maya city. It is based on the analysis of LiDAR, and field and laboratory data. This approach has revealed the mosaic of current ecological conditions of the wetlands, thanks to the characterisation and spatial modelling of the landforms, hydrology, vegetation and soil cover. It has enabled the characterisation of numerous hydraulic and agricultural structures: 70 large reservoirs, raised fields (the largest over 1.5 km²), canals and ditches (with a cumulative length of over 300 km) and dikes. Eight morphological types of hybrid structures—hydraulic and agricultural—are described. These constructions have enabled the intensive exploitation of water and soil resources, their management and the resulting environmental risks. This study has shown that the agroecosystems of lowland areas were created as early as ~1500 B.C.E. and evolved in a polyphasic way, until a phase of radical decline around 1000 C.E. This study has made it possible to characterise the legacy of the Maya Early Anthropocene on current wetlands, as well as their important natural and cultural heritage.

Pemberdayaan Kelompok Pembudidaya Ikan Desa Pakowa Bunta dengan Menggunakan Ekstrak Daun Sirih (Piper betle L.) dalam Pakan pada Budidaya Ikan Nila Sistem Bioflok

Pakowa Bunta Village is one of the villages in Nuhon District, Banggai Regency, physically it is a lowland area located on the coastline. The large area of tilapia ponds in Pakowa Bunta Village and the suboptimal management of tilapia cultivation have caused many tilapia fish to die. The repeated failure of cultivation in the traditional system of tilapia cultivation in Pakowa Bunta Village requires the transfer of innovative fish cultivation technology from the traditional system to the biofloc system. This community service activity aims to improve the skills and knowledge of fish cultivator groups regarding biofloc system fish cultivation and increase the economic income of fish cultivators in Pakowa Bunta Village. The approach used to resolve partner problems in this activity is the Community Development method, which is oriented towards developing community empowerment by making the community the subject and object of development and direct involvement in various service activities. The final result achieved from this community service activity is an increase in the skills of the fish cultivator group in innovating tilapia cultivation technology using a biofloc system that is modified by using betel leaf extract in the feed given to tilapia, resulting in an increase in tilapia production and an increase in the community's economic income of fish farmers.

Особенности социальных конструкций Дагестана и их влияние на общественно-политические процессы в регионе

The article examines the features of geographical diversity and socio-political development of Dagestan in the 18th – early 19th centuriy. The major role of natural-geographical determinism is emphasized, which influenced the forms of economic structure, the dominant sectors of economic activity and the socio-political processes that differed depending on the spatial localization of the regions. In high mountain areas, due to harsh landscape conditions and a shortage of available vital resources, archaic forms of economic activity and social structure were preserved for a long time. It was dominated by free rural communities with collective ownership of the main means of production. Foothill, coastal and lowland areas, due to their less closed nature and accessibility to external influences and mutual influence, as well as the possibility of obtaining a large set of life benefits, went beyond the socio-cultural archaism and represented territories with a developed system of social differentiation, which most domestic researchers define as feudalism. In such areas, local societies, earlier than in the mountainous ones, were forced to socio-political development, which took them beyond the boundaries of communal-tribal relations. In economic and socio-political terms, Dagestan was divided into socio-cultural formations that differed and competed with each other.