Ecological and Climatic Insights from Seasonal Ponds of Nediyenga, Kerala, India: Vegetation Diversity and Environmental Variability

Many chronic diseases are adversely affected by elevated iron levels. It has been speculated that this relationship is mediated by increased oxidative stress, due to the ability of iron to generate reactive oxygen species. The aim of this study was to assess the relationship between elevated iron levels and lipid peroxidation in Caucasian adults residing in the north-eastern Mediterranean region of Spain. This cross-sectional case-control study included 300 subjects: 150 adults displaying elevated iron levels (cases) selected from a representative sample of our general population and 150 age- and sex-matched adults exhibiting normal iron levels (controls). Dietary assessment (3-day food records), iron biomarkers (serum iron, ferritin and transferrin saturation) and lipid profile were determined. Elevated iron levels were defined by high serum ferritin (SF>110 μg/L in women and>200 μg/L in men) and/or transferrin saturation (TS)>45%. Oxidized low-density lipoprotein (oxLDL) plasma levels were measured, and oxLDL/LDL-cholesterol ratio was calculated to estimate lipid peroxidation. Multiple linear regression (MLR) models were applied. Individuals with elevated serum iron levels showed increased oxLDL/LDL ratio, but not oxLDL levels, compared to control subjects (20·92 ± 4·89 U/mmol vs. 19·72 ± 3·573 U/mmol, P = 0·028). These results were further confirmed by the regression models adjusted for demographic characteristics, diet, lipid profile and inflammation. Importantly, higher serum levels of triglycerides, LDL-cholesterol and lower intake of Vitamin E increased lipid peroxidation. In our general population, we have observed that higher circulating levels of iron, measured by serum ferritin and/or TS, increased lipid peroxidation (measured by oxLDL/LDL ratio).

Relationship between vegetation diversity and soil functional diversity in native mixed-oak forests

Abstract.Two developments in the understanding of the relationship between sedimentary pollen assemblages, vegetation and plant diversity are discussed. The Prentice model of vegetation–pollen relationships has improved our understanding of how and at what scale sedimentary pollen records vegetation. The modelling framework allows improved palaeoecological study designs that may, potentially, give important new insights into processes of plant migrations in response to climate change. Also, reconstructions of plant communities and landscape openness may be improved. Competing hypotheses for the relationship between vegetation and palynological diversity are discussed and it is concluded that more attention should be focused on evenness aspects of palynological diversity and on hypothesis testing.

Iron and lipids combine to create oxidative stress, and oxidative stress has a role in the development of cancer. The objective was to determine the risk of cancer among persons who had both elevated iron and lipids. The authors conducted an analysis of the cohort available in the Framingham Offspring Study. Adults aged 30 or more years at baseline had serum iron and high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol, and very low density lipoprotein cholesterol (VLDL-C) assessed in 1979-1982 and were followed for development of cancer until 1996-1997 (n = 3,278). Cox regression models were computed while controlling for age, gender, smoking status, and body mass index. In adjusted models, both elevated iron (hazard ratio (HR) = 1.66, 95% confidence interval (CI): 1.11, 2.46; 29 cases) and VLDL-C (HR = 1.54, 95% CI: 1.04, 2.28; 93 cases) had significant independent risks for development of cancer. When elevated iron was combined with elevated VLDL-C, the adjusted relative risk of cancer increased (HR = 2.68, 95% CI: 1.49, 4.83; 18 cases). Elevated iron and low HDL-C also had a significant adjusted relative risk of cancer (HR = 2.82, 95% CI: 1.50, 5.28; 14 cases). The results suggest that elevated serum iron levels coupled with either high VLDL-C or low HDL-C appear to interact to increase cancer risk in this cohort.

Ephemeral Wetlands

Anthropogenic climate change is expected to be a major driver of worldwide biodiversity losses. Non-use values can play an important role in the evaluation of strategies to combat these losses or to reduce anthropogenic climate change. However, non-use values may not be transferrable across contexts with different pressures on biodiversity. Contrary to expectations in economic theory, they may be determined not only by outcomes, but also by what causes the outcomes. Given that no extant studies have specifically estimated the willingness to pay (WTP) for reducing the impact of climate change on biodiversity, we compare the WTP more generally for reducing anthropogenic and natural pressures on biodiversity. We conduct a meta-regression analysis informed by data obtained from stated preferences studies focusing on non-use values of biodiversity conservation. We assess whether non-use values for improving or avoiding losses of habitats and species are affected by policy responses addressing anthropogenic or natural pressures. We estimate meta-regression models in which we explain the variation in biodiversity non-use values by accounting for the observed heterogeneity in good, methodology, sample, and context characteristics. We estimate meta-regression models using 159 observations from 62 publications. The models suggest that non-use values for biodiversity conservation addressing anthropogenic pressures may be 95–131 percent larger than those facing natural pressures. We also find that non-use values are generally not sensitive to habitat types or the scope of species preservation. The evaluation of climate policy in terms of biodiversity non-use values should be based on valuations of the effect of anthropogenic pressures on biodiversity, instead of inferring these benefits from a wide variety of existing studies. Furthermore, there is a clear need for additional valuation research focusing on estimating non-use values, specifically for climate change-induced biodiversity losses.

The forests of South Ecuador have high conservation value because they are highly threatened, but also possess high diversity and endemism levels. However, as the process of conservation is inherently spatial, the little available information about the factors that promote vulnerability of these forests as well as the spatial distribution of the conservation targets have produced some conservation pitfalls. The main objective of this dissertation was to generate spatial information about the threats and biological values occurring in this region to prioritize areas for conservation. The second chapter analyzes the deforestation and fragmentation patterns in the region since the 1970s using aerial photographs and satellite images to identify areas with remaining forest, fronts of deforestation, annual deforestation rates and the dynamics in the composition and configuration of the landscape of South Ecuador. We recorded annual deforestation rates of 0.75% (1976 – 1989) and 2.86% (1989 – 2008) for two consecutive survey periods. Also, we found that South Ecuador is experiencing an ongoing fragmentation process due to an increase in the number of patches, a decrease in mean patch size and an increase in the isolation of forest fragments. This study also contributes to a better understanding of forest change dynamics in the tropics. We found that substantial portions of natural forests are being degraded or converted into pastures and that main fronts of deforestation are located in the lowest areas in the premontane evergreen forest. The third chapter describes the temporal and spatial patterns of human pressure, as it is one of the main factors that influence the effectiveness of conservation strategies. At local scale, we adapted at local scale the Human Footprint Index (HF) developed by Sanderson et al. (2002), to evaluate spatial changes in HF during a 26 year period at both landscape and ecosystem levels. This information allowed us to identify “hotspots of change” and the wildest areas remaining in order to evaluate how different human proxies contribute to HF and to demonstrate how effective the most important protected areas have been in reducing human pressure inside and outside their boundaries. The findings show a noticeable increase in human pressure levels in South Ecuador and a progressive reduction in the wildest areas. We also identified that the important “hotspots of changes” are located in the western region and the Rio Zamora river basin. The most impacted vegetation types were seasonally dry forest and shrubland. Here, population density is the human proxy with the highest contribution to the observed patterns. Finally, we found that Podocarpus National Park has been partially effective in reducing human pressure inside and outside its borders. HF levels have increased inside and outside the boundaries of the protected area, but the human pressure was always lower than that observed in the surrounding landscape. The fourth chapter analyzes the patterns of alpha and beta diversity of endemic plant species to evaluate the congruence of both patterns and to identify areas with the highest diversity of endemic plants in order to prioritize areas for conservation. We found that hotspots of alpha diversity are concentrated along the Andes, but this diversity was only slightly congruent with beta diversity patterns of endemic plants mostly concentrated in the western and eastern escarpments of the Andes, and in the Coastal and Amazon cordilleras. We also found that approximately 40% of the areas with the highest alpha and beta diversities have already disappeared due to deforestation and that only 30% is under protection in Ecuador. Thus, we propose 12 potential areas with a high priority of conservation mostly located in South Ecuador to improve the representativeness and complementarity of the current reserve network. Finally, the fifth chapter synthesizes the principal findings of this thesis highlighting the implications for conservation and suggesting potential areas to be preserved based on human pressure levels, remaining forest and alpha and beta diversity patterns of endemic plants.

In this study, we analyzed the effects of grazing on native and endemic plant diversity, as well as its relationship with pastoral value along a gradient of abiotic and biotic factors and types of land management in a mountainous area of central-eastern Sardinia, Italy. Plant diversity was estimated by conducting a floristic survey within plots. In total, 231 plant species were recorded in 63 plots distributed within the study area, and this total number included 20 endemic species. Species richness was mainly affected by the type of management, soil attributes, altitude, and bioclimate. Pastoral value was strongly affected by nutrient availability and bioclimate. Our results suggest that the cover of endemic species increases with altitude. Finally, in Sardinian rangelands, a negative effect of grazing pressure on endemic species was observed.

Based on high-resolution palynological analysis of 680 samples from a core, short-term changes in plant diversity and floristic composition within the Paleogene greenhouse were detected in the lacustrine succession of a lower to middle Eocene maar lake at Messel (Federal State of Hesse, Germany). The microfloristic data show that taxonomic diversity increased rapidly within some decades during recolonization of a volcanically devastated area around the lake. With the establishment of a climax vegetation at the end of recolonization, the maximum in palynological diversity was reached within the crater area. During the following 640 Kyr the composition of the palynospectrum changed only gradually. However, different richness and evenness estimations show that alpha and gamma diversity decreased up to 35%, which can be related to the establishment of an equilibrium stage within the climax vegetation that led to the dominance of an assemblage of self-replacing species. Nevertheless, time-series analysis of alpha-diversity changes within the climax vegetation reveals that orbitally controlled climate change of Milankovitch and sub-Milankovitch order influenced the diversity of the vegetation, resulting in a rise of beta diversity. Based on the composition of the vegetation and comparison to modern analogues, our analysis proves that Eocene paratropical plant diversity increased during periods of slightly higher temperature and precipitation. Therefore, both composition and diversity of the vegetation was highly susceptible to minor-scale, short-term changes in climate, even during equable greenhouse conditions.

The expansion of oil palm plantations is often rumored to impact the destruction of forests and other ecosystems with high conservation value (HCV). This study aimed to analyze the vegetation and plant diversity in the HCV area of oil palm plantations. The research was conducted on an oil palm plantation in Seruyan District, Central Kalimantan Province, Indonesia with an HCV area of 5379 ha. The research was carried out using the grid transect method on various types of vegetation, divided into four plots: seedlings, saplings, poles and trees. Parameters observed included the number of species, the number of individuals and the level of plant diversity. The results showed that the research location had good vegetation and plant diversity in the HCV area. There were 25 plant species from 17 families with a total of 355 plants. The number of species found in the seedling plots was 11 species (6 families) with a total of 38 plants; in the sapling plots was 16 species (12 families) with a total of 159 plants; in the pole plots was 14 species (11 families) with a total of 43 plants, and in the tree plots was 13 species (10 families) 115 plants. There was variation in the number of species and families in each plot. The overall plant diversity index was low. The diversity index of plants in the plots of seedlings, saplings, poles and trees (and the average) was in the low category.

As a critical ecological barrier and water reservoir in northwest China crucial for regional sustainable development, the Tarim River Basin necessitates comprehensive analysis of its ecological sensitivity distribution and driving factors. In this investigation, we have woven together the Remote Sensing Ecological Index with the sensitivity assessment framework, constructing a comprehensive 15-indicator system for assessing ecological sensitivity. When elucidating the underlying determinants of ecological sensitivity within a watershed, employing the Optimal Parameter Geographic Detector (OPGD) model to discern the primary impetuses. The results showed that habitat quality analysis classified 56.53% of the basin as substandard, concentrated in central-eastern deserts under extreme aridity, while only 6.79% qualified as high-quality zones in northern vegetated areas. Topographic insensitivity dominated, with 70.08% of slopes exhibiting non-responsiveness, and human activities intensified fragility, as 25.09% of the area showed sensitivity to road proximity. Vegetation diversity and soil type interactions demonstrated equivalent explanatory power, with q-values of 0.657. Thermal-hydrological coupling emerged as a critical mechanism, prompting strategies like thermal buffer zones and precision irrigation to mitigate sensitivity hotspots. These results advance arid ecosystem governance by linking spatial heterogeneity to conservation policies. The Optimal Parameter Geodetector identified heat and temperature as dominant drivers, with q-values of 0.731 and 0.7045, respectively. Their synergistic interaction (q = 0.82) amplified thermal impacts from anthropogenic land modifications like irrigation infrastructure. These findings provide critical insights for informing ecological conservation strategies, offering actionable pathways to enhance the resilience and sustainable management of the basin’s ecosystems.

Soil and water characteristics in micro basins with different land uses/land cover (LULC) can influence riparian vegetation diversity, stream water quality, and benthic diatom diversity. We analyzed 18 streams in the upper part of the La Antigua River basin, México, surrounded by cloud forests, livestock pastures, and coffee plantations. Concentrations of P, C, and N were elevated in the humus of forested streams compared to other land uses. In contrast, cations, ammonium, and total suspended solids (TSS) of water streams were higher in pastures and coffee plantations. These results indicate that LULC affects stream chemistry differently across land uses. Vegetation richness was highest (86-133 spp.) in forest streams and lowest in pastures (46-102), whereas pasture streams had the greatest richness of diatoms (9-24), likely due to higher light and temperatures. Some soil and water characteristics correlated with both true diversity and taxonomic diversity; soil carbon exchange capacity (CEC) correlated with vegetation diversity (r = 0.60), while water temperature correlated negatively (r = - 0.68). Diatom diversity was related to soil aluminum (r = - 0.59), magnesium (r = 0.57), water phosphorus (r = 0.88), and chlorophyll (r = 0.75). These findings suggest that land use affects riparian vegetation, while physical and chemical changes influence diatom diversity in stream water and soil. The lack of correlation between vegetation and diatom diversity indicates that one cannot predict the other. This research is an essential first step in understanding how land use changes impact vegetation and diatom diversity in mountain landscapes, providing valuable insights for environmental monitoring and conservation efforts in tropical cloud forests.

Conservation of nature and natural resources has been an important part of cultural ethos, especially in remote rural and indigenous communities in many parts of the world, including India. These communities consider themselves connected with their biophysical environment in a web of spiritual relationships. Sacred groves are the relic forest segments preserved in the name of religion and culture. These groves are mostly associated with temples and are also culturally important. They manifest the spiritual and ecological ethos of rural indigenous communities. Many taboos are associated with sacred grove which helps in managing resources well through ritual representation. Different festivals are organized, where the local communities reaffirm their commitment to the forest and the deity. Sacred groves, in general, are a valuable tool of biodiversity conservation. The sacred groves as the treasure of repositories of a variety of plant species, the present study is conducted to find out the plant diversity in the sacred grove, Thekkumbad Thazhe Kavu in Kannur district, Kerala. 15 species present in this Kavu are least concerned, and they are Acanthus ilicifolius, Achrosticum aureum, Aegicera scorniculatum, Bruguiera cylindrica, Caryota urens, Cyperus ratundas, Fimbristilis ferrugenea, Kandelia candel, Lindernia crustacea, Lindernia tenuifolia, Ludwiga hyssopifolia, Pandanus odorifer, Panicum repens, Rhizophora apiculata and Rhizophoram ucronata. The species Caryota urens securing higher IVI of 38.835. The species of least significance (lowest IVI) were shown by Derris trifoliate, Emilia sonchifolia and Rhizophora apiculata. Based on IVI score made by this species it is understood that these are poorly established species in the communities of the study site.

Background: The South Aegean Volcanic Arc (SAVA), one of the most notable geological structures of the Mediterranean Sea, is floristically well known. Nevertheless, the factors that contribute to shaping the plant species richness of the SAVA remain unclear.Aims: To investigate the factors that affect plant species richness and identify plant diversity hotspots in the SAVA and other central Aegean islands.Methods: We used stepwise multiple regression to test the relationship between a number of environmental factors and plant species richness in the SAVA, as well as the residuals from the species–area linear regressions of native, Greek and Cycladian endemic taxa as indicators of relative species richness.Results: The area was confirmed to be the most powerful single explanatory variable of island species richness, while geodiversity, maximum elevation and mean annual precipitation explained a large proportion of variance for almost all the species richness measures. Anafi, Amorgos and Folegandros were found to be endemic plant diversity hotspots.Conclusions: We have demonstrated that geodiversity is an important factor in shaping plant species diversity in the Cyclades, while mean annual precipitation, human population density and maximum elevation were significant predictors of the Greek endemics present in the Cyclades. Finally, Anafi was found to be a plant diversity hotspot in the South Aegean Sea.

Water chemistry and titratable acidity and malic acid levels in Isoetes howellii leaves were sampled every 6 hr from plants in a seasonal pool and an oligotrophic lake. Plants in the seasonal pool showed a diurnal fluctuation of ~ 300 μequivalents titratable acidity g−1 fresh wt; daytime deacidification was 75% complete by noon and nighttime acidification was 45% complete by midnight. Late in the season after the pool had dried, emergent leaves showed only a very weak tendency to accumulate acid at night. Plants from the oligotrophic lake had a diurnal change of ~100 μeq g−1 fresh wt, daytime deacidification was only 45% complete by noon but nighttime acidification was 80% complete by midnight. Water characteristics were distinctly different between these two systems. In the seasonal pool there were marked diurnal changes in temperature, pH, oxygen and carbon dioxide. Free‐CO2 levels were an order of magnitude greater in the early morning than in the late afternoon. In contrast, the conditions in the oligotrophic lake showed no marked diurnal fluctuation, though total inorganic carbon levels were extremely low relative to other aquatic systems.