Changes In Land Use Practices Research Articles

The Evolution of Agrarian Landscapes in the Tropical Andes.

Changes in land-use practices have been a central element of human adaptation to Holocene climate change. Many practices that result in the short-term stabilization of socio-natural systems, however, have longer-term, unanticipated consequences that present cascading challenges for human subsistence strategies and opportunities for subsequent adaptations. Investigating complex sequences of interaction between climate change and human land-use in the past-rather than short-term causes and effects-is therefore essential for understanding processes of adaptation and change, but this approach has been stymied by a lack of suitably-scaled paleoecological data. Through a high-resolution paleoecological analysis, we provide a 7000-year history of changing climate and land management around Lake Acopia in the Andes of southern Peru. We identify evidence of the onset of pastoralism, maize cultivation, and possibly cultivation of quinoa and potatoes to form a complex agrarian landscape by c. 4300 years ago. Cumulative interactive climate-cultivation effects resulting in erosion ended abruptly c. 2300 years ago. After this time, reduced sedimentation rates are attributed to the construction and use of agricultural terraces within the catchment of the lake. These results provide new insights into the role of humans in the manufacture of Andean landscapes and the incremental, adaptive processes through which land-use practices take shape.

Wildlife as sentinels for emerging zoonotic diseases: A review of surveillance systems in the USA

Wildlife plays a crucial role as sentinels for emerging zoonotic diseases, serving as early indicators of potential threats to human and animal health. This review examines the surveillance systems in the USA that utilize wildlife as indicators for the presence of emerging zoonotic pathogens. The review focuses on the methodologies, challenges, and implications of these surveillance systems. In the USA, wildlife surveillance for zoonotic diseases is primarily conducted through passive surveillance, where wildlife carcasses are collected and tested for pathogens. Additionally, active surveillance programs target specific wildlife species known to host zoonotic pathogens or species that may be in close contact with humans or domestic animals. These surveillance efforts are complemented by the use of sentinel species, such as birds or bats, which are monitored for signs of disease that could indicate the presence of zoonotic pathogens. Challenges in wildlife surveillance include the vast geographic range of many wildlife species, making it difficult to sample populations comprehensively. Additionally, the diversity of wildlife species and habitats in the USA presents logistical challenges for surveillance efforts. Furthermore, there are challenges related to data sharing and coordination among agencies responsible for wildlife and public health. The implications of wildlife surveillance for public health policy and practice are significant. Early detection of zoonotic pathogens in wildlife can lead to timely public health interventions, such as vaccination campaigns or changes in land use practices to reduce human-wildlife contact. Moreover, wildlife surveillance can inform the development of predictive models for disease outbreaks, enabling more effective preparedness and response measures. In conclusion, wildlife surveillance plays a critical role in the early detection and monitoring of emerging zoonotic diseases in the USA. Continued investment in surveillance systems and research is essential to enhance our understanding of zoonotic disease dynamics and improve our ability to protect human and animal health.

Changes in water surface area of the Middle Atlas-Morocco lakes: A response to climate and human effects

The lakes represent crucial surface water resources and an integral part of wetlands. The most concerning aspect of the degradation of these areas is the complete drying up of the lakes. In the Mediterranean region, successive changes in land use practices in the context of climate change have strongly influenced wetland areas. In this study, we used Landsat TM, OLI, and OLI-2 satellite images to monitor the water surface area in two representative lakes (Aoua and Ifrah) of the Tabular Middle Atlas and to map land use across the entire study area. To extract information related to lakes and land use, we employed the Support Vector Machine machine learning algorithm, widely used in remote sensing studies. However, we identified drought periods from precipitation data using the Standardized Precipitation Index (SPI) recommended by the World Meteorological Organization (WMO). The results obtained from the processing of Landsat satellite images indicate a significant reduction in the surface area of the lakes, with periods of drying for Aoua lake, endangering their fragile ecosystems and biodiversity. The critical situation of the two lakes is attributed to a combination of natural and anthropogenic factors. The analysis of climatic data shows a significant climate change from the 1980s, with long periods of drought. In parallel, the study area has undergone remarkable modifications in land use patterns, mainly characterized by a significant extension of irrigated agricultural surfaces to the detriment of grazing and rainfed lands. In three decades, the area of irrigated crops has increased from approximately 1300 hectares in 1985 to 7070 hectares in 2022, representing an increase of 542%. The findings presented in this study reveal the extent of lake degradation in the TMA and reflect the alarming decline in groundwater levels. This situation indicates the necessity of formulating a strategy to protect water resources and wetlands in the Middle Atlas.

Changes in land use practices influence soil sulfur fractions and their bioavailability

Changes in land use practices may affect the distribution of soil sulfur (S) fractions and their bioavailability. Therefore, this study was undertaken to assess the influence of different land use changes on the distribution of soil S fractions and their bioavailability for plant nutrition. Soil samples from farmers’ fields with different land use practices such as rice-mustard-jute (R-M-J), rice-lentil-jute (R-L-J), rice-lentil-sesame (R-L-S), rice-vegetable-jute (R-V-J), and rice-potato-green gram (R-P-G) were collected and analyzed for different fractions of S. The bioavailability of S was assessed by extracting the soil with six different extractants (acidic, neutral, and alkaline) with different extraction modes and chemistry. The results showed that changes in land use practices could influence the distribution of soil S fractions and their bioavailability. Organic S was the dominant fraction, accounting for 93.5% of total S across land use practices. The inorganic S fraction (water-soluble, sorbed, and occluded) varied significantly among the land use practices. Among the inorganic fractions, the water-soluble fraction was the dominant fraction across the land use practices. The bioavailability of S, as assessed by different chemical extractants, was in the following order: sodium hydrogen carbonate (NaHCO3) > mehlich-3 > ammonium bicarbonate-diethylenetriamine penta-acetic acid (AB-DTPA) > ammonium acetate-acetic acid (NH4Ac-HOAc) > calcium dihydrogen phosphate {Ca(H2PO4)2} > calcium chloride (CaCl2). By establishing relationships between extractable S and soil S fractions, it was observed that all the extractants could obtain S from the water-soluble, sorbed, and organic S fractions, with little extractability from the occluded fraction. Among the extractants tested, mehlich-3 extracted a similar amount of S corresponding to the inorganic fraction across the land use practices. It also maintained positive relationships with different fractions of S, and as a multi-nutrient extractant, its use in routine soil testing can be recommended.

Ecological risk assessment on nutrient over-enrichment in water quality: A case study of the Kenyan Coral Reef ecosystems

The natural (seasonality) and anthropogenic drivers (e.g., coastal developments and change in land-use practices), continue to threaten the lives of organisms in shallow marine environments by compromising water quality. A case study was conducted to assess the impact of these drivers on nutrient over-enrichments using water and sediment samples that were collected from healthy live Porites spp. colonies from three Kenyan coral reef ecosystems: Tana Delta, Watamu, and Shimoni Mupunguti Reef. The evaluated nutrient over-enrichment levels were above the universal reference background concentrations of 0.01 and 0.003 mg/L for (N-(NO3- + NO2-)) and (P-PO43-) respectively. Ecological risk exposure to nutrient over-enrichments was evaluated using Renfield (N/P) ratio and nitrogen-phosphorous pollution index. Results on N/P ratios were < the Renfield ratio (N/P = 16 ratios), implying that phosphorous was in surplus in water columns in all the three reefs investigated. The nitrogen pollution indices were between > 0.85 to ˂ 2.45, while that of phosphorous, the pollution indices were < 0.5. The nutrient over-enrichment followed the order; Watamu > Tana Delta > Shimoni Mupunguti coral reef ecosystem. To identify the possible sources of the nutrient influx in the investigated coral reef ecosystems, a principal component analysis was carried out, and results revealed that anthropogenic activities e.g., tourism, coastal cities urbanization and change in land use practices accounted for 36.26%, while seasonality accounted for 17.82% of the total nutrients influx in the investigated coral reefs.

Greening and Browning Trends on the Pacific Slope of Peru and Northern Chile

Accurate detection and quantification of regional vegetation trends are essential for understanding the dynamics of landscape ecology and vegetation distribution. We applied a comprehensive trend analysis to satellite data to describe geospatial changes in vegetation along the Pacific slope of Peru and northern Chile, from sea level to the continental divide, a region characterised by biologically unique and highly sensitive arid and semi-arid environments. Our statistical analyses show broad regional patterns of positive trends in EVI, called “greening”, alongside patterns of “browning”, where trends are negative between 2000 and 2020. The coastal plain and foothills, up 1000 m, contain notable greening of the coastal Lomas and newly irrigated agricultural lands occurring alongside browning trends related to changes in land use practices and urban development. Strikingly, the precordilleras show a distinct ‘greening strip’, which extends from approximately 6°S to 22°S, with an altitudinal trend, ascending from the tropical lowlands (170–780 m) in northern Peru to the subtropics (1000–2800 m) in central Peru and temperate zone (2600–4300 m) in southern Peru and northern Chile. We find that the geographical characteristics of the greening strip do not match climate zones previously established by Köppen and Geiger. Greening and browning trends in the coastal deserts and the high Andes lie within well defined climatic and life zones, producing variable but identifiable trends. However, the distinct Pacific slope greening presents an unexpected distribution with respect to the regional Köppen–Geiger climate and life zones. This work provides insights on understanding the effects of climate change on Peru’s diverse ecosystems in highly sensitive, biologically unique arid and semi-arid environments on the Pacific slope.

Analyzing changes in land use practices and livelihoods in the Bhungroo irrigation technology Volta basin piloted sites, West Mamprusi District, Ghana

This study focused on assessing agricultural land use practices and livelihood changes as affected by long-term erratic rainfall patterns characterized by flood and drought cycles in the Bhungroo Irrigation Technology (BIT) piloted sites, West Mamprusi upper and lower catchment area in Ghana. The study defined environmental flow restoration (EFR) factors based on irrigation water demand, natural outflows (e.g. drainage, seepage and percolation), evaporative outflows, rainfall and stored water. Agro-ecological resilience (AER) factors included flooding intensity, crop production under dry season, flood recession, and irrigation, and livestock as well as mixed farming was assessed. The framework of Evaluating Sustainable Land Management (FESLM) was utilized to assess changes in land use and trends analyzed by the Auto Regressive Integrated Moving Average (ARIMA) technique. The main observed land use practices were subsistence cultivation with limited irrigation 72.8%, subsistence cultivation without irrigation 64.5% and livestock keeping with some cultivation 87.4%. Corresponding land use mean weights impact on the EFR and AER were 9, 9, 8, and 9, 8, 7 respectively. The study noted that precipitation was of higher significance than temperature in terms of hydro-climate determinants in both upper and lower catchment areas. Mean monthly precipitation amount and intensity were highest between June–July in the upper catchment while in the lower catchment it was between July–August. These months corresponded with high risk of flooding and waterlogging in both catchments. The opposite was observed in March with access to irrigation water being the most EFR factor influencing the resilience of BIT especially at the upper catchment area. In terms of academic contribution, this paper posits in the hydro-climatic context that excess pressure exerted from a combination of micronized factors such as waterlogging of farmlands, flood recession rate, irrigation capabilities, climate preparedness, adoption and transferability of innovations and scalability of climate innovations are likely be the critical elements which accelerate the climate vulnerability of arid and semi-arid catchment areas. Based on these observations, the study carefully recommends improved BIT infrastructure, including the integration of grundfos pumping systems, solar pay-as-you-go energy, MTN mobile payment systems, participatory decision support systems (PDSS), with improved awareness on determinants of EFR including crop-livestock integration in ecological organic agriculture as resilience building options.

Escape from the garden: spreading, effects and traits of a new risky invasive ornamental plant (Gaillardia aristata Pursh)

Ornamental plants constitute a major source of invasive species.Gaillardia aristata(great blanketflower) is planted worldwide and its escape has been reported in several European countries without ecological impact assessment on the invasive potential. As there is a markedly spreading population with invasive behaviour in Hungary, we aimed to reveal the distribution, impacts and traits ofG. aristata. We gathered occurrence data outside the gardens in Hungary, based on literature, unpublished observations by experts and our own records. We investigated the impacts of an extended population, where the species invaded sandy old-fields within a 25 km2area. Here, we compared the species richness, diversity, community composition and height of invaded and uninvaded vegetation. Furthermore, we evaluated the traits potentially associated with the invasiveness ofG. aristatain comparison with other herbaceous invasive species in the region. We found thatG. aristataoccurred mostly by casual escapes, but naturalised and invasive populations were also detected in considerable numbers.G. aristatausually appeared close to gardens and ruderal habitats, but also in semi-natural and natural grasslands and tended to spread better in sandy soils. We found lower plant species richness and Shannon diversity in the invaded sites and the invasion ofG. aristatasignificantly influenced the composition of the plant community. The trait analyses revealed that the invasive potential ofG. aristatais backed by a wide germination niche breadth, extremely long flowering period, small shoot-root ratio (large absorption and gripping surface), large seeds (longer persistence) and dispersal by epizoochory of grazing livestock (mostly by sheep), probably helping the species’ survival and spreading in the disturbed, species-poor, sandy, open habitats. These functional traits, as well as the ornamental utilisation, may act together with the aridisation of the climate and the changing land-use practices (e.g. abandoned, disturbed sites) in the success ofG. aristata. We raise awareness of the rapid transition ofG. aristatafrom ornamental plant to casual alien and then to invasive species in certain environmental conditions (i.e. sandy soils, species-poor communities, human disturbances), although it seems to be not a strong ecosystem transformer so far. Nonetheless, banning it from seed mixtures, developing eradication strategy and long-term monitoring of this species would be important to halt its spreading in time.

Abundance, diversity and distribution of Macrophytes in lotic wetlands: A case study on Sironga and Kapkatet Wetlands, Kenya

Wetland macrophytes provide important ecological and social-economic values. However, the recent increase in anthropogenic influences has compromised the ecological integrity of most lotic wetlands, which has ultimately threatened their structure and functioning, causing degradation and loss of macrophytes. This study was aimed at assessing the biodiversity, distribution and abundance of macrophytes in Sironga and Kapkatet wetlands with respect to various anthropogenic activities. Sampling was conducted for a period of six months, covering both dry and wet seasons from February – July 2019. Macrophytes were identified using identification keys and diversity indices such as the Shannon-Wiener, Simpson’s, and Species evenness were used to determine macrophyte diversities. The numbers of different macrophytes species was enumerated from five randomly sampled line transects along the water ways and another fifteen also randomly distributed on the wetlands on a monthly basis. There were three main lifeforms of aquatic macrophytes found in both Sironga and Kapaktet wetlands namely, emerged, submerged and floating, which were dominated by Centella asciatica and Cyperus sp. and the floating macrophytes, Potamogeton schwenfurthii dominated Kapaktet wetland. The study found that macrophyte distribution, abundance and biodiversity were highly affected by predominant economic activities resulting to wetland conversion, nutrient influxes and unsustainable exploitation of macrophytes. We recommend a further study focusing on effects of sedimentation resulting from unsustainable agricultural practices on water quality and macrophytes diversity, distribution and abundance, the effects of changing land-use practices and how different environmental agencies can be involved in the advocacy, conservation and management of the riverine wetlands.

Evaluating Changes in Land Use Practices and Livelihoods in the Bhungroo Irrigation Technology Volta Basin Piloted Sites, West Mamprusi District, Ghana

Evaluating Changes in Land Use Practices and Livelihoods in the Bhungroo Irrigation Technology Volta Basin Piloted Sites, West Mamprusi District, Ghana

Land use/Land Cover Dynamics in Pioneer Fronts and Implications on Livelihoods: Insights from Nkuh and Nkuv on the Bui Plateau

Land use dynamics in pioneer fronts in Sub-Saharan Africa is recurrent; yet, stakeholder interests and the various changes in land-use practices are still to be fully mainstreamed in resource use practices. The implications for livelihood improvement are indicative of the attracting force of these areas to different stakeholders. This study sets out to: 1. Map land use and land cover change in Nkuh and Nkuv pioneer fronts in the Bui Plateau; 2. Identify stakeholders and interests in pioneer fronts; 3. Understand land use change practices and implications for livelihoods. The study used diachronic analysis accompanied by 7 focus group discussions, 9 key informant interviews across native authorities and some government delegations on thematic analysis and narratives. The results revealed that small agroplantations are the major land-use changes from the existing rangelands and remnants of natural forests. Farmers from neighboring villages have migrated and settled in pioneer fronts, practicing agriculture through expansion, stabilization and consolidation. Diversification and adoption of new techniques like agro-forestry, agro-plantations (oil palms, fruit trees, cocoa) is growing amongst farmers, especially among return migrants, bureaucrats and land-use change/ land-use practices have important implication for livelihood improvement for the population implicated with an increase in output. Further studies can focus on how local endogenous processes and power asymmetries can improve resource use outcomes.

Influence of redox gradients on nitrate transport from the landscape to groundwater and streams

Increases in nitrogen applications to the land surface since the 1950s have led to a cascade of negative environmental impacts, including degradation of drinking water supplies, nutrient enrichment of aquatic ecosystems and contributions to global climate change. In this study, groundwater, streambed porewater, and stream sampling were used to establish trends in nitrate concentrations and how redox gradients influence nitrate transport across diverse glacial terranes. Decadal sampling has found that elevated nitrate concentrations in shallow groundwater beneath cropland have been sustained for decades. Redox gradients established in the saturated zone using dissolved O2, iron, nitrate and excess N2 from denitrification suggest that nitrate-bearing zones are thin in glacial terranes dominated by fine materials. These thin nitrate-bearing zones lead to suboxic, low nitrate streambed porewater and limit the contributions of nitrate to streams from slow-flow groundwater. In contrast, thick oxic zones in more coarse-grained glacial terranes allow nitrate to reach deeper groundwater, resulting in streambed porewater with elevated nitrate concentrations and causing a large portion of stream nitrate to be derived from slow-flow groundwater. Groundwater age tracer data indicate that denitrification occurs more quickly in the terrane dominated by fine material than in the more coarse-grained terrane. The quicker depletion of nitrate in the more fine-grained terrane suggests that the thinner oxic zone in this terrane is due, in part, to the greater availability and reactivity of electron donors in this terrane than in the more coarse-grained terrane. Groundwater age tracer data and hydrograph separation analysis suggest that saturated zone lag times between when changes in land use practices occur and when changes in stream water are fully observed may vary widely across hydrogeologic settings.

Geospatial approach to evaluate the morphometry of Sabarmati River Basin, India

River basins play an essential role in ecosystem stability; they receive water through either snowmelt or precipitation which helps in groundwater resource development. Thereupon, land and water are ecologically linked which sustain the livelihood and food security. Since the river flows from higher to lower elevation, it carries sediment, nutrients or pollutants along with water flow to the outlet of the basin via channels. From the last few decades, the rapid change in land-use practices has led to water scarcity especially in the semi-arid region where there is an imbalance between precipitation and evapotranspiration. Therefore, there is a crucial requirement for water resource planning. The present morphometric analysis work has been performed on the Sabarmati River Basin, which falls in the semi-arid region of western India. Digital elevation model data, geostatistical tools and ArcGIS have been used to explore the hydrological and geomorphic processes in the basin. The morphometric variables like relief and areal and linear aspects were calculated to delineate the basin’s drainage network. The area showed a dendritic drainage pattern with drainage density of 0.42 km−1 which infers the less permeable surface of the basin with thin vegetation and moderate to high elevation. The highest stream order of the basin is seventh order with an area of 31,921 km2 and basin length of 481.75 km. The circulatory ratio of 0.18 and low-form factor of 0.14 infer the basin’s elongated nature which increases the chances of water infiltration. This work will assist the decision-makers for allocation of artificial recharge points to reduce runoff in the basin for sustainable soil and water resource planning.

Effects of the type of forest alteration on gross nitrogen mineralization in soils of southern India

Change in land-use practices can result in major shifts in the cycling of various elements, particularly nitrogen (N), which is prone to anthropogenic perturbations. For quantifying these shifts, accurate measurements of rates of biogeochemical transformations of N are needed. We used the (15N) isotope dilution technique to understand the effects of the types of forest alteration on (N) transformation rates by comparing gross N mineralization and ammonium (NH4+) consumption rates in soils of a managed forest, an unmanaged forest, and a rubber plantation in Kerala, India. Overall, nitrate (NO3−) dominated soils of the managed and unmanaged forests, whereas soils in the rubber plantation showed relatively higher NH4+ concentration. Total N (TN) and total organic carbon (TOC) concentrations were the highest under the rubber canopy (TN: 1.49 ± 0.02 mg N g−1; TOC: 7.96 ± 0.86 mg C g−1). In soils of all three forest types, gross N mineralization rates were higher compared to NH4+ consumption rates. Despite high TN and TOC concentrations, the rates of gross N mineralization and NH4+ consumption were considerably lower in the rubber plantation (mineralization: 1.08 ± 0.08 mg N kg−1 d−1; consumption: 0.85 ± 0.09 mg N kg−1 d−) compared to the managed (mineralization: 3.71 ± 0.35 mg N kg−1 d−1; consumption: 2.20 ± 1.41 mg N kg−1 d−1) and unmanaged (mineralization: 2.20 ± 1.07 mg N kg−1 d−1; consumption: 1.39 ± 0.27 mg N kg−1 d−1) forests. The lower NH4+ consumption rates in the rubber plantation led to significantly higher (p < 0.05) residence time of NH4+ (~ 4 days) compared to the managed and unmanaged forests (< 2 days), possibly contributing to acidification of rubber soils (pH ~ 4.8). These results together suggest that replacement of naturally grown forests with a mono-cropped plantation such as rubber negatively impact rates of N transformation processes in tropical soils and imply that change in tree species composition of naturally grown forests can adversely affect soil microbial activity. We recommend intercropping these plantations with commercial crops to maintain soil microbial diversity and biogeochemical cycling for sustainable forest management.

Herpetofaunal responses to intensification of woody bioenergy production in a global biodiversity hotspot

Bioenergy produced from woody biomass in managed forest systems represents a substantial portion of the global supply of renewable energy. As societies transition to renewable energy and demand for wood-based bioenergy increases, timber-producing forests and other agricultural and marginal lands may transition to bioenergy management regimes. Limited empirical information exists regarding how wildlife communities will respond to bioenergy intensification. We investigated herpetofaunal occurrence across 75 study sites located in two types of bioenergy feedstocks (corn and pine) to evaluate effects of bioenergy alternatives in a global biodiversity hotspot in the southeastern United States: the North American Coastal Plain. We found that removing harvest residue following clearcut management in pine forests as a source of woody biomass resulted in either neutral or positive effects for six of the seven herpetofaunal species examined. Other bioenergy alternatives, such as mid-rotation thinning and short-rotation practices, resulted in highly variable effects among individual species and generally contrasting effects between amphibians and reptiles. Similarly high variability was observed when comparing species occurrence patterns between corn and managed pine bioenergy feedstocks. Our study suggests herpetofaunal community responses to changing land-use practices in the era of bioenergy may be taxa- and species-specific. Some land-use practices (e.g., residue removal following clearcuts) may be generally compatible with conservation of most species examined, but conserving herpetofaunal diversity within the Southeast as bioenergy production increases may involve promoting heterogeneous managed landscapes in which a diversity of harvest approaches are used.

Analysis of Discharge Variability in the Naryn River Basin, Kyrgyzstan

Changing climate and land-use practices influencing the natural stream flow processes in the Naryn river basin of Kyrgyzstan. Variations in stream flow regime over 33-years (1980 to 2012) were investigated using daily discharge data of three hydro-stations (Naryn, Ych-Terek and Uzunakmat), located in the Naryn River Basin. Mean monthly discharge (MMD), mean annual discharge (MAD), standard deviation (SD) and coefficient of variation (CV) were calculated to know the spatio-temporal variability. Similarly, Pearson’s correlation coefficient (r) was used to know the relationship between discharge and rainfall. Advanced time-series graph, exceedance probability and frequency distribution were computed using Hydrognomon (V.4.0.3) software to observe the variability and trends in discharge. The results from statistical calculations and software-based computations highlight the monthly, annual, and long term spatio-temporal discharge variability, extreme events, distribution and changes in stream flow records. This study preciously creates the frequency and trends of seasonal discharge, annual discharge cycle, and range of highest and lowest discharge flows. The weak and negative relationship (-0.2121, -0.4238) between rainfall and discharge propose for more investigation of climatic parameters and the topography of Tian Shan Mountain perhaps influencing discharge variability due to melting of glacier at high altitude. The flow regime of the Naryn river basin over the past 33-years perhaps changed due to climatic fluctuations, with the seasonal snowmelt timing (Post-Spring, Summer, Pri-Autumn), precipitations period (March-October), and large-scale land-use alterations.

Modelling the dry season inundation pattern of Yala Swamp in Kenya

Ecological processes in wetlands rely on the natural variability of inundation cycle guided by different seasons. Human-induced modifications have, however, influenced the seasonality and the period of inundation, altering its inherent variability. The adjustments have further affected the functioning of many global wetlands by shifting their natural equilibrium. In a quest to understand the wetland’s inundation pattern, cellular automata and Markov chain analysis (CA–MCA) model was used to simulate the 2029 dry season inundation variation of Yala Swamp in Kenya. The model utilised parameters obtained from Tasselled Cap Wetness Index, supervised classification, population growth model and elevation for the years 1986, 2006, 2015 and 2019. The study established that inundation characteristics in the swamp varied as the years progressed from 1986 to 2019. Consistency was found between inundation variation and changes in land-use practices. Consequently, the area covered by the wetland decreased in its spatial extent by approximately 35%. The model projected that the swamp would additionally lose 12% of its inundated area by 2029, should the current practices continue. It is therefore essential to regulate anthropogenic activities to control the variability in the swamps inundation.

Dust deposition tracks late-Holocene shifts in monsoon activity and the increasing role of human disturbance in the Puna-Altiplano, northwest Argentina

The Puna-Altiplano plateau represents a regionally significant dust source, which is critically located at the nexus between the tropical and sub-polar synoptic systems that dominate the South American climate. Dust emissions in this region would therefore be expected to be sensitive to changes in these systems, in particular the strength and position of the South American Summer Monsoon (SASM). Here, we present a late-Holocene multi-proxy study where changes in dust flux, reconstructed from a high-altitude peat mire, are examined in light of climate variability and human impacts. Results show that for most the 4300 cal. yr BP record, dust flux sensitively tracked changes in SASM activity. Prior to 2600 cal. yr BP relatively high dust flux implies dry conditions prevailed across the Puna-Altiplao in association with reduced SASM activity. The chemistry of dust deposited at this time matched the large endorheic basins on the Puna, which host ephemeral lakes and terminal fans, indicating these were actively supplying dust to the airstream. After 2600 cal. yr BP, SASM activity increased while dust flux decreased and the dust chemistry changed, collectively implying the shutting down of the Puna-Altiplano as a significant dust source. Dust flux increased after 1000 cal. yr BP during the ‘Medieval Warm Period’, associated with a return to drier conditions and reactivation of dust sources across the endorheic basins of the Puna. Natural variability in dust flux was dwarfed, however, by the very significant increase in flux after 400 cal. yr BP following Spanish Colonisation and associated changing landuse practices. This finding attests to the globally significant role of humans on dust emissions.

Assessment of water quality status of Doyang River, Nagaland, India, using Water Quality Index

The Doyang River of Wokha district, Nagaland, NE India, has a strong economic and traditional attachment to the local people. It provides sufficient fertile plains and slopes for cultivation, good grounds for community fishing and hunting. It is not only important for the people of Wokha but also for the state of Nagaland because of the rich natural resources it provides. This study was conducted to assess the Water Quality Index (WQI) of the Doyang River from eight selected sampling stations. Maximum WQI values were recorded during monsoon season in all the stations followed by pre-monsoon and post-monsoon. Sampling stations located in the upstream of the river experience deteriorating WQI due to the presence of hydroelectric dam, changing landuse practices, increasing settlements and deforestation in the catchment and river banks. The overall WQI values showed good water quality status indicating suitability for different human uses. The present study points out that pH, DO and BOD played a central role in affecting the WQI of the river; however, in case of nutrient elements no such significant roles were observed in affecting the water quality of the river. The condition of water quality in our present study felt the necessity to adopt proper management policy and conservation efforts along the riparian zones of Doyang River.

Mussels partition resources from natural waters under flowing conditions

The feeding of three co-occurring freshwater mussel species (Ptychobranchus fasciolaris, Quadrula quadrula and Potamilus alatus) of differing conservation status on river water from their collection site was examined under static and ecologically relevant flow conditions using three characteristics of the suspended river seston from a turbid river (Sydenham River, Ontario): (1) Chlorophyll a fluorescence; (2) size of fluorescent particles determined under flow cytometry; and (3) individual algal taxa identified under flow cytometry. Differences in the clearance rate (CR; water volume cleared of material per mussel and time) based on changes in chlorophyll a concentration were observed among species (P. alatus > Q. quadrula). Mussels had higher CR under flowing conditions and higher CR were observed on four of the nine algal taxa under flowing conditions. Feeding electivity analysis indicated that all mussel species selected for larger particles (28–35 μm size fraction) while rejecting smaller ones (12–19 μm). Whereas mussels did not appear to partition resources by size, mussel species exhibited resource partitioning of algal taxa (i.e., selectively feeding on different algal species; under flowing conditions: small centric diatoms were preferred by P. fasciolaris and Q. quadrula and avoided by P. alatus; Cryptomonas were preferred by P. fasciolaris and avoided by Q. quadrula and P. alatus; Chloromonas were preferred by P. alatus and avoided by P. fasciolaris). This study provides a novel mechanism, hydrodynamically mediated resource partitioning, in which the partitioning of resources occurs from within a flowing fluid rather than through the spatial or temporal partitioning of resources by organisms exploiting different microhabitats, to explain the existence of high mussel species richness within the same river reach (i.e., 24 species in this study). Unfortunately the species specific relationships noted above are likely vulnerable to climate change and changes in land use practice due to agriculture and urbanization.