Wet Climate Research Articles

Grewia tembensis Fresen and Grewia trichocarpa Hochst. ex A.Rich. (Grewioideae Hochr; Malvaceae Juss.) Micromorphological Study and Comparison via Electron Microscopy

Grewia tembensis and Grewia trichocarpa inhabit dry tropical zones and arid environments, adapting to extreme climatic conditions and limited moisture supplies. Overall, Grewia L. possesses a significant variety of bioactive chemical constituents of great therapeutic importance. Indeed, for these species, precise morphological analyses are poor, and their detailed characterization is almost non-existent. This research attempts to investigate and compare the micromorphological traits of G. tembensis and G. trichocarpa species through scanning electron microscopy (SEM). Micromorphological characteristics of the leaf and fructiferous structures turned out to be highly effective in separating the two species, G. tembensis and G. trichocarpa, especially regarding the type, density, and distribution of trichomes on the lower and upper surfaces of the leaves, along with the stomatal and trichome types on the surfaces of the fruits. Statistical analyses using principal component analysis, t-tests, and hierarchical clustering conducted on micromorphological data of the leaves, flowers, and fruits showed considerable variation within samples of G. tembensis and samples of G. trichocarpa. On the basis of their morphological assessment characteristics, the samples of both species were distinct and clustered into separate groups. This study emphasizes the necessity of performing detailed morphological studies of species by means of an electron microscope and proves that the leaf features are important for separating species. Such morphological traits of trichomes would offer an efficient tool to distinguish the species. Within the findings, this suggests that such diagnostics are likely to be highly useful for species identification in Grewia, especially in cases where there are no fruits available.

Are planting site conditions more important than soil amendments when direct seeding in the semiarid Mallee in regional Victoria, Australia?

Direct seeding is a potentially valuable method for restoration in arid areas due to its low cost and labor input but suffers from the drawback of reduced survival rates, which may lead to planting failure. As such, the addition of soil amendments may be one way to increase planting success rates. This study investigated whether the addition of three types of soil amendments (fertilizers, hydrogels, and microbial inoculants) would be able to increase the emergence and survival times of direct seeding works in the semiarid Mallee region of north‐west Victoria, Australia. Seed from four native species were mechanically directly seeded into three sites across the Mallee region, along with different combinations of soil amendments. Emergence and survival time were recorded for 1 year, and the soil properties at each planting location were analyzed. The results showed that only the two larger‐seeded species (Acacia ligulata and Callitris gracilis) were able to emerge, while the two smaller‐seeded species (Eucalyptus calycogona and Melaleuca lanceolata) showed no emergence. Soil amendments had no effect on either seedling emergence or survival time. Instead, seeding location had a significant outcome for both seedling emergence and survival. It was found that locations that showed the highest emergence did not necessarily show the highest survival. Low soil nutrient sandplains contained the highest seedling emergence counts. The longest surviving seedlings were in locations with slightly higher nitrogen levels for A. ligulata seedlings, while C. gracilis survived longest in highly sandy soil under a slightly cooler, wetter climate.

Toward Designing Bioretention Landscapes for Tropical and Wet Equatorial Climates: A Systematic Literature Review

Cities worldwide face significant challenges in managing stormwater, a concern worsened by rapid urbanization and the impacts of climate change. Bioretention landscapes helped solve these issues by replicating natural ecosystems to effectively capture, filter, and treat stormwater while offering additional ecosystem services. However, most studies and existing guides have been for colder and drier climates. Adapting bioretention practices to tropical and wet equatorial climates, characterized by intense rainfall patterns and high temperature and humidity, presents unique challenges and knowledge gaps. This systematic literature review aims to address these gaps by synthesizing existing research from 2010 to 2022 on bioretention landscapes in tropical and wet equatorial climates. Following the methodology outlined in PRISMA guidelines, we identified 10 key studies primarily focusing on countries within the Köppen–Geiger climate zones Aw, Af, and Am, which are tropical and wet equatorial climates. These studies spanned across different continents, including locations such as Malaysia, Singapore, Burkina Faso, and India. Data synthesis revealed critical design elements, including planting selection, substrate layer composition, and performance metrics. Our findings highlight the necessity for climate-specific design approaches and identify key research gaps that can inform future studies and guide practical applications in designing bioretention landscapes for tropical and wet equatorial climates.

Distribution and conservation status of Ligularia sibirica (Asteraceae) in Europe, with special reference to Ukraine

Based on our thorough analysis of bibliographical and herbarium data and field surveys of historical and existing localities of Ligularia sibirica, a detailed map of its distribution in Europe is presented, which significantly supplements and clarifies the previous information, particularly concerning Ukraine, Poland, and partly Russia. The distribution and status of the species in each European country within its range is described. A special map is also provided for Ukraine, where the species has suffered the greatest decline. In some regions, L. sibirica as a relic boreal species is endangered and has been undergoing decline and extirpation at least since the 19th century. The main threat factors are climate changes and anthropogenic activity, particularly the drainage amelioration of wetlands. Adverse consequences of climate changes mostly concern localities in the plain terrain south-westwards from the boreal zone. In general, mountain populations demonstrate better persistence because the colder and wetter climate conditions in the mountains are more favorable for L. sibirica.

Assessing current and future areas of ecological suitability for Lutzomyia shannoni in North America

BackgroundIn the Americas, sand flies of the Lutzomyia genus are the vectors of pathogens of human and animal health significance. Lutzomyia shannoni is suspected to transmit vesicular stomatitis virus, along with Leishmania mexicana and Leishmania infantum (causative agents of leishmaniases). Despite the suspected vector potential of Lu. shannoni, significant knowledge gaps remain, including how ongoing climate changes could facilitate their range expansion. The objectives of this study were to predict the current and future ecological suitability of regions across North America for Lu. shannoni and to identify variables driving ecological suitability.MethodsOccurrence records were obtained from the Global Biodiversity Information Facility, Disease Vectors Database, the National Museum of Natural History (Smithsonian Institution) and published literature on Lu. shannoni surveillance and capture. Historical climate data from 1991–2020, along with projection data for Shared Socioeconomic Pathways 2–4.5 and 3–7.0 were obtained. An additional terrestrial ecoregions layer was applied. The ecological niche model was created using maximum entropy (MaxEnt) algorithms to identify regions which currently are or may become ecologically suitable for Lu. shannoni.ResultsCurrently, regions in eastern, western and southern Mexico, along with the Midwest, southeastern and eastern regions of the USA are ecologically suitable for Lu. shannoni. In the future, ecological suitability for Lu. shannoni is expected to increase slightly in the northeastern regions of the USA and in Atlantic Canada, and to decrease in the southeastern reaches of Mexico. Degree-days below 0 °C (spring and autumn), precipitation as snow (summer and winter), terrestrial ecoregions, number of frost-free days (summer), Hargreaves climatic moisture deficit (summer), degree-days above 5 °C (autumn) and Hogg’s climatic moisture index (summer) were all identified as predictors of ecological suitability.ConclusionsThe findings from this study identified climate and environmental variables driving the ecological suitability of regions for Lu. shannoni and can be used to inform public health professionals of high-risk regions for exposure at present and into the future.Graphical abstract

Freshwater fish condition responses to hydrological disturbance are species- and scale dependent.

Modification of river flows is a major cause of freshwater fish population declines in many parts of the world. Identifying the precise mechanisms of these declines represents a significant challenge, as a range of stressors can simultaneously impact various components of fish health, fitness and population dynamics. Here we investigate the role of river flows and other biophysical factors on spatio-temporal variation in freshwater fish body condition in Australia's highly modified Murray-Darling Basin using three widely distributed native (Murray cod Maccullochella peelii, golden perch Macquaria ambigua and bony herring Nematalosa erebi) and one introduced (common carp Cyprinus carpio) species. Our aim was to uncover drivers of spatio-temporal variation in fish condition at two spatial extents: at the basin scale, utilising a flow regime disturbance index, and at the river-valley scale, employing individual flow gauge data to assess responses in fish condition to multiple measures of antecedent (365 day) flow. Linear mixed effects modelling revealed that at the basin scale, M. peelii and M. ambigua were in better condition in rivers with lower flow regime disturbance, and temporal trends in the condition of N. erebi, C. carpio and M. peelii reflected boom and bust dynamics related to wet and dry climate periods. At the river-valley scale, mean antecedent daily flow magnitude was significantly positively related to the condition of M. peelii, M. ambigua and C. carpio, whereas the number of high-flow days was negatively related to condition of N. erebi. Our study demonstrates that a simple body condition index calculated from routinely collected length-weight data is sensitive to multiple measures of hydrological disturbance in river systems that experience substantial temporal and spatial variability. We emphasise that studies considering multiple spatial scales are important for understanding complex scale-dependent mechanisms influencing fish condition.

Permafrost Peatland Initiation and Development in Late Holocene of the Northeast China.

Peatlands play an important role in the global carbon cycle. However, the initiation and development of permafrost peatlands and their responses to climate change remain unclear, hindering our understanding of the past and future of this region. In this study, we reconstructed the evolution of permafrost peatlands in the Greater Khingan Mountains (GKM) of Northeast China since 3500 cal yr BP using palynological evidence from permafrost peatland core and AMS14C dating. The results indicated that from 3500 to 2900 cal yr BP, the vegetation mainly composed of Pinus, thermophilic broad-leaved trees, and Polypodiaceae, with a warm and wet climate constituting the peatland incubation period. From 2900 to 2250 cal yr BP, the vegetation mainly composed of Pinus, thermophilic broad-leaved trees, and Artemisia, with a peatland initiation period characterized by a warm and humid climate. From 2250 to 1650 cal yr BP, the vegetation mainly composed of Pinus, Betula, and Polypodiaceae, with a cold and wet climate allowing peatland to flourish. From 1650 to 750 cal yr BP, the vegetation mainly composed of Pinus and Artemisia, and a dry, cold climate led to a slowdown or stagnation in peatland development. Later in this period, a warmer and wetter climate allowed the peatland to develop again, thereby completing the transition from eutrophic to mesotrophic state. Since 750 cal yr BP, the vegetation mainly composed of Pinus and Cyperaceae, indicating a colder and wetter climate allowing the peatland to flourish again, and peatlands began to change to oligotrophic state. Our results showed that the evolution of the GKM permafrost peatlands is mainly influenced by climate, and permafrost peatland development in the future will depend on trends in global climate.

Impacts of increasing compound hot-dry events on vegetation under the warming-wetting trend in Northwest China

Impacts of increasing compound hot-dry events on vegetation under the warming-wetting trend in Northwest China

Landscape Evolution Models of Incision on Mars: Implications for the Ancient Climate

AbstractLarge dendritic valley networks observed on Mars present a paleoclimate paradox. Geologic observations of Noachian units on Mars reveal a global extent of valley networks, which are believed to have been formed through incisions made by flowing water. However, most climate models predict global surface temperatures too far below the freezing point of water to support an active hydrological system. Conflicting observations and models have led to disparate theories for the climate of early Mars. In this work, we surveyed a large region of the cratered southern highlands to identify the location, elevation, and distribution of observed valley heads. These valley head locations were compared to landscape evolution simulations in which the spatial distribution of runoff was varied. The measured valley head distributions were compared to predictions from landscape evolution models for two end‐member hypotheses: (a) a warm wet climate that supported spatially distributed precipitation, and (b) surface runoff from ice cap margins, as envisioned by the Late Noachian Icy Highland model (LNIH). The observed elevation distribution in valley heads is consistent with the prediction of precipitation‐fed models, and inconsistent with models in which runoff derives exclusively from a single line‐source of high‐elevation ice‐melt. The results support the view that it is unlikely for ice caps to be the sole source of water and are consistent with the hypothesis that precipitation significantly contributed to valley network formation on ancient Mars.

Analysis of alluvial fan surface coefficients to understand the Himalayan foothill instability in the Koshi-Mahananda interfluve area, East Nepal

The foothills of the eastern Nepal Himalayas form a colony of alluvial fans. The fan surfaces are extensively used for tea plantations and their associated land use, like dense settlements and intensive crop cultivation. Dynamic surfaces of the fans are unfavorable for a stable land use pattern and hamper human life. It is necessary to identify the dynamic natures and their cause over the fan surfaces to avoid unfavorable circumstances and for preventive measures. Fan surface coefficients show that most of the alluvial fans of the study area are highly unstable. The perennial stream supplies huge sediments in a wet climatic environment, which causes an alluvial fan instability in the eastern Nepal Himalayan foothills. The studied fan areas are derived from small river basins (2nd order) that supply a relatively low amount of sediments, but the fans are highly dynamic. This study reveals that frazil surface due to huge deforestation of geological structures under high neotectonics and high stream competency due to wet climate are responsible for this instability.

Opposing trends in winter Atmospheric River over the Western and Eastern US during the past four decades

Winter atmospheric rivers (ARs) are crucial for water supply and extreme weather events over the western (WUS) and eastern US (EUS), yet their long-term trends and interplay remain unclear. Here we fill this gap by analyzing multiple observational AR products over the past four decades. Contrasting yet interrelated trends emerge in AR frequency, intensity, and associated mean precipitation. A decline in AR activity over WUS contributes to a drying trend, while notable increases over EUS foster a wetter climate. These trends are driven by large-scale atmospheric and oceanic variability in the Pacific, which strengthens anticyclonic circulation patterns near both coasts. These anticyclonic patterns, however, have opposing effects–impeding ARs from steering to WUS while facilitating their development over EUS. Our findings present a unified explanation for the observed AR trends and have co-beneficial implications for mitigating concerns related to AR-induced extreme events across both densely populated coastal regions.

Classifying the potential for soil organic carbon gain under regenerative agriculture

Abstract Regenerative agriculture is pivotal for mitigating climate change, with no-tillage practices on cropland being generally effective at raising soil organic carbon (SOC). Yet, our understanding of the compound impact of soil and environmental factors on SOC gain potential after transitioning to no-till practices is still developing. Using imbalanced machine learning classification, here we quantify key thresholds to hierarchically classify SOC gain potential by switching from conventional tillage to long-term no-tillage with residue retention. Our findings reveal that antecedent SOC level exerts the primary influence, with a reduced gain potential for antecedent SOC exceeding 50 tonnes per hectare. Wet climate (Dryness Index < 1.5) and low productivity (net annual primary productivity < 5.5 tonnes per hectare) could further lessen the effectiveness of SOC sequestration. These key thresholds identify vast areas across Africa, Australia, South Asia, Southern Europe, and parts of North and South America as high-potential croplands for carbon sequestration and offer guidelines for assessing the reliability of regenerative agriculture in local and regional contexts.

Modern pollen deposition in relation to different vegetation types in the Jaintia Hills of Meghalaya, Indo-Burma region: implications for palaeoecological reconstructions

This study documents the relationship between modern pollen deposition and vegetation types in the Jaintia Hills of Meghalaya, India. Five characteristic modern pollen assemblages are recognised based on the representation of marker pollen taxa observed in the surface soil samples obtained from different areas based on vegetation types and land use. The Pinus–Alnus–Betula–Quercus–Schima–Impatiens assemblage is associated with subtropical pine forest with a relatively cold and wet climate. The Schima forest is characterised by the Schima–Cinnamomum–Alnus–Quercus–Pandanus–Impatiens pollen assemblage. The evergreen forest is characterised by the Mesua–Syzygium–Duabanga–Ilex–Nepenthes–Dendrophthoe assemblage, indicative of the warm and wet climate in response to the high rainfall activity in this region. The grassland was characterised by the presence of the non-cereal–Cyperaceae–Pandanus–Schima–Asteroideae–Cichorioideae–Impatiens assemblage in the Jaintia Hills. The cropland was represented by cereal–Polygonum–Pinus–Schima–Nepenthes–Impatiens palyno-assemblages. Multivariate principal component analysis (PCA) was applied and showed a close correlation between the recorded pollen assemblage in relation to the different vegetation types in Jaintia Hills. The different forest types, especially evergreen and Schima wallichii (DC.) Korth., forests, along with the consistent recovery of Nepenthes and Pandanus pollen reflect the vicinity of coastal habitats in this part of the Indo-Burma region. This investigation demonstrates that this newly developed modern pollen analogue could be a potential proxy for the interpretation of palaeovegetation and palaeoclimate in the Jaintia Hills and other adjacent regions of the Indo-Burma biodiversity hotspot.

Recent large-inland-lake outbursts on the Tibetan Plateau: processes, causes, and mechanisms

Abstract. Research into lake outburst events has been mainly focused on small glacial lakes in the Himalaya, while historical events from large inland lakes are few and have received less attention. Large inland lakes on the Tibetan Plateau are expanding rapidly, with recent signs of increasing outburst risk, highlighting the need to elucidate their processes, their causes, and mechanisms to mitigate future impacts. Here, long-term satellite lake mapping shows that the number and surface area of lakes on the Tibetan Plateau have exhibited an increasing trend over the past 50 years, peaking in 2023. Two notable outburst events occurred during this period: Zonag Lake (∼ 150 km2 in 2023) on 15 September 2011 and Selin Co (∼ 2465 km2 in 2023, the largest lake in Tibet) on 21 September 2023. The cascading outburst of Zonag Lake caused its area to shrink by ∼ 124 km2 (−45 %), while the downstream Yanhu Lake expanded by ∼ 163 km2 (+347 %). The Selin Co outburst resulted in a water mass loss of ∼ 0.3 Gt, and Bange Co downstream experienced a water level rise of ∼ 2.3 m and an area expansion of ∼ 18 %. Despite its large water storage capacity, Selin Co experienced less water loss due to the flat terrain at the breach and the slow flow (∼ 1 m s−1 at the damaged road), with an average discharge of ∼ 154 m3 s−1. Even with the low discharge, the Selin Co flood breached the lowland road within ∼ 10 h. In contrast, the large breach and steep terrain at Zonag Lake facilitated the rapid discharge of a sustained volume of water, with an average discharge of ∼ 2238 m3 s−1. Selin Co resulted in only a short period of drainage reorganization in contrast to the permanent reorganization caused by Zonag Lake. The underlying mechanisms of the increased precipitation as the main trigger for the two outburst events prior to the occurrence are different. For Zonag Lake, thermodynamic effects, i.e., changes in the atmospheric moisture, are the most important, while for Selin Co, dynamical effects, i.e., the vertical moisture motion induced by changes in atmospheric circulation, dominate the precipitation patterns. Large-lake outbursts on the inner Tibetan Plateau are expected to increase in the near future due to the warmer and wetter climate, and urgent policy planning is needed to mitigate the potential future lake-induced flood damage.

Increasing Agricultural Inputs: Autonomous Adaptive Response to Climate Change and Variability Effects in Selected South Asian Countries

The amount, duration, and timing of climatic factors like temperature, rainfall, and moisture are major determinants of crop production. In South Asia, more than 60% of agriculture is rainfed and susceptible to climate change and variability. Multiple climatic events, such as erratic and excessive rainfall, increasing temperature, longer dry spells, heat waves, and droughts, have had a major negative impact on production and farmers' livelihoods. Agricultural inputs are another major factor that determines agriculture production and productivity. This study explores the type of agricultural inputs, and utilization by smallholder farmers in the context of climate change and variability in selected study sites of three South Asian countries, Nepal, India, and Bangladesh. A descriptive exploratory research approach was adopted and the analysis is based on both primary and secondary data and document review. To comprehend the effects of climate change on agricultural input, we use a sample household survey of 633 farmers (211 in each country) together with six key informant interviews (KII) and three focus group discussions (FGD). The analysis of primary and secondary data exhibits four key agriculture inputs, fertilizer, pesticides and insecticides, improved crop and seed varieties, and irrigation facilities. The limited use of modern tools and machinery is evident due to higher investment costs for resource-poor smallholder farmers. The increased use of fertilizer and pesticides adheres to the adverse effects of climate change and variability particularly decreasing crop yield and increasing rodents and pests. It is reasoned that increased use of selected input harms environment sustainability, crop production, and productivity in the long run. This study concludes that developing environment-friendly and climate-resilient inputs, regulatory monitoring for efficient and productive use of inputs, and ensuring the availability and affordability of agricultural inputs to all farmers are vital for environmental sustainability, and increased agriculture production and productivity.

Wind speed and soil properties drive the height-diameter allometric pattern of island plants.

Island ecosystems, due to their geographical isolation and unique environmental conditions, often serve as natural laboratories for ecological research and are also sensitive to global climate change and biodiversity loss. The allometric relationship between plant height-diameter reflects the adaptive growth strategy of plants under different environmental conditions, particularly in response to biomechanical constraints (e.g., wind resistance) and resource availability. This study aims to explore the key driving factors of the height-diameter allometry of island plants, focusing on how island area, soil properties, and climatic factors (e.g., wind speed, temperature, and precipitation) affect plant growth strategy. We analyzed plant data from 20 tropical islands, using SMA regression to calculate the allometric exponent and intercept for each island's plants, and evaluated the effects of island area, soil properties, and climatic factors (wind speed, temperature, and precipitation) on the height-diameter allometric relationship. The results show that island area has no significant effect on plant allometry, while climatic factors, particularly wind speed, and soil properties significantly influence the allometric exponent and intercept, respectively. Specifically, wind speed is the primary driver of the height-diameter allometric exponent, regulating plant growth proportions through mechanical stress and canopy limitation. In contrast, soil properties predominantly govern changes in the allometric intercept, reflecting their critical role in determining baseline growth conditions, such as resource allocation and initial morphological adaptation. The effects of temperature and precipitation are relatively weak, likely due to the buffering effects of the tropical climate and marine moisture supplementation. Overall, this study highlights the key roles of wind speed and soil in shaping the allometry of island plants, providing new insights into the adaptive strategies of island plants under resource limitations and climatic pressures, as well as offering important scientific evidence for island ecological conservation and restoration.

Hot Weather Amplifies the Urban Dry Island Effect, Especially in Wetter Climates

AbstractAtmospheric humidity is usually drier in cities than the surrounding rural areas, a phenomenon known as the urban dry island (UDI) effect. However, the response of atmospheric humidity to hot weather in urban versus rural settings remains unknown. Using long‐term summer (June–August) observations at 1662 stations over 1961–2020, we find that China is dominated by drying trends in atmospheric humidity (i.e., increasing vapor pressure deficit (VPD)). These drying trends are aggravated on hot days and amplified by urbanization, that is, the UDI effect is stronger in hot weather. This amplification of the UDI effect on hot days is more prominent in humid than in arid regions. Attributions show that the stronger VPD‐based UDI effect on hot days is explained by increased contribution of air temperature in southeastern China and specific humidity in northern China. We suggest that adaptations are required to mitigate adverse combined effects of urban heatwaves and UDIs.

Assessment of climate change impacts on streamflow in the Inner Niger Delta under CMIP6 scenarios

ABSTRACT The Inner Niger Delta (IND) is an important water source for agricultural water supply, fish production, and livestock breeding. It sustains the livelihoods of more than 3 million people and is a driver of the rural economy of Mali. However, the growing water demand and the anticipated effects of climate change cast some uncertainties on the future of the resources in the basin. In this research, the effects of projected climate change on the water resource in terms of streamflow were investigated using the semi-distributed catchment model Niger-HYPE. The model was first calibrated, validated, and then forced with future rainfall, temperature, and potential evapotranspiration (PET) to simulate the future streamflow for 2021–2050 under two Shared Socioeconomic Pathways (SSPs), namely SSP126 and SSP370. Results indicated a warmer and wetter climate in the basin with an increase in the mean annual rainfall, temperature, and PET on average by 6.5%, 1.25 °C, and 5.3%, respectively. The annual streamflow increased by 7% and 10% for SSP126 and SSP370, respectively. These results have many implications for water resource management in the basin. Adaptation and mitigation strategies are necessary to counter the negative impacts of an anticipated drier dry season.

Multidecadal drought impacts on the Lower Colorado Basin with implications for future management

Overallocation of Colorado River water and groundwater alongside multidecadal drought underscore the need to understand water-resource dynamics. Here we assess water-storage variations using satellites, regional modeling, and monitoring to inform future management. Total water storage loss from Gravity Recovery and Climate Experiment (GRACE) satellites was dominated by Lower Basin declines (80% of total), exceeding Lake Mead capacity by 40%. These Lower Basin storage declines were dominated by groundwater depletion (60% of total), with cumulative depletion hotspots ≤11 m (2002–2023) and subsidence ≤1 m (2010–2024). Regional groundwater modeling shows intensive depletion (1940s–1970s) followed by partial recovery since the early 1980s from irrigation reduction, wet climate cycles (early 1980s–1990s), and Colorado River water transfers to Central Arizona. Managed aquifer recharge and incidental recharge from imported surface-water irrigation led to a 3-m average groundwater-level rise in Central Arizona Active Management Areas (2000–2023). Projected declines in Colorado River water transfers to Central Arizona could lead to further depletion and subsidence. Water transfers from agricultural to municipal/industrial sectors would improve future management. Understanding system dynamics related to climate and human drivers is essential for developing future conjunctive surface-water and groundwater management strategies.

The Effect of Rainfall Anomalies on the Productivity of Clove Plants (Syzygium aromaticum) and Management Strategies in Southeast Sulawesi

Climate change has caused rainfall anomalies that have an impact on decreasing the productivity of clove plants (Syzygium aromaticum). This study aims to analyze extreme rainfall anomalies in North Buton Regency and Kolaka Regency, assess its impact on the productivity of clove plants (Syzygium aromaticum), and formulate management strategies that can be applied to increase crop yields. The method used is a quantitative descriptive approach with linear regression analysis to determine the relationship between rainfall and clove productivity. The research population is clove farmers in North Buton Regency and Kolaka Regency, with a sample of three farmers in each village where the research is located. Rainfall data was obtained from the Betoambari Bau-Bau Meteorological Station and the Sangia Nibandera Kolaka Meteorological Station during the 2009–2023 period, while clove crop productivity data was obtained from farmer surveys and reports from the Central Statistics Agency. The results of the study show that North Buton Regency has an average annual rainfall of 1,971 mm with slightly wet climate characteristics (Type C), while Kolaka Regency has an average annual rainfall of 1,973 mm with wet climate characteristics (Type B). Based on the evaluation of the suitability of the rainfall land, it is included in the S1 category (very suitable). Regression analysis showed that rainfall had a less significant relationship with the productivity of clove plants. The results of the regression analysis showed that the determination coefficient (R2) of North Buton Regency was 12.59% and Kolaka Regency was 14.21%. Recommended management strategies to deal with rainfall anomalies in Kolaka Regency include improving drainage systems, soil management and conservation, and environmental sanitation. Meanwhile, in North Buton Regency, it includes the provision of irrigation, the use of mulch and the provision of organic matter.