A new estimate of carbon for Bangladesh forest ecosystems with their spatial distribution and REDD+ implications

In tropical developing countries, reducing emissions from deforestation and forest degradation (REDD+) is becoming an important mechanism for conserving forests and protecting biodiversity. A key prerequisite for any successful REDD+ project, however, is obtaining baseline estimates of carbon in forest ecosystems. Using available published data, we provide here a new and more reliable estimate of carbon in Bangladesh forest ecosystems, along with their geo-spatial distribution. Our study reveals great variability in carbon density in different forests and higher carbon stock in the mangrove ecosystems, followed by in hill forests and in inland Sal (Shorea robusta) forests in the country. Due to its coverage, degraded nature, and diverse stakeholder engagement, the hill forests of Bangladesh can be used to obtain maximum REDD+ benefits. Further research on carbon and biodiversity in under-represented forest ecosystems using a commonly accepted protocol is essential for the establishment of successful REDD+ projects and for the protection of the country’s degraded forests and for addressing declining levels of biodiversity

The use of medicinal plants in health care practices by Rohingya refugees in a degraded forest and conservation area of Bangladesh

People in developing countries traditionally rely on plants for their primary healthcare. This dependence is relatively higher in forests in remote areas due to the lack of access to modern health facilities and easy availability of the plant products.We carried out an ethno-medicinal survey in Teknaf Game Reserve (TGR), a heavily degraded forest and conservation area in southern Bangladesh, to explore the diversity of plants used by Rohingya refugees for treating various ailments. The study also documented the traditional utilization, collection and perceptions of medicinal plants by the Rohingyas residing on the edges of this conservation area. We collected primary information through direct observation and by interviewing older respondents using a semi-structured questionnaire. A total of 34 plant species in 28 families were frequently used by the Rohingyas to treat 45 ailments, ranging from simple headaches to highly complex eye and heart diseases. For medicinal preparations and treating various ailments, aboveground plant parts were used more than belowground parts. The collection of medicinal plants was mostly from the TGR. © 2009 Taylor & Francis

Effects of Climate Change on Plants and Ecosystem Functioning: Implications for Managed Temperate Grasslands

Global climate change poses challenges to plants and ecosystem functioning. Grasslands have become a major study object in experimental biodiversity and climate impact studies. The great majority of the existing studies investigated the effects of climate change on productivity. However, studies on how climate change (such as 1000-year drought, high precipitation variability, seasonal warming, late frost in spring etc.) affects flowering phenology, plant physiology, community composition, legume facilitation, plant nitrogen (N) and soil N status in managed temperate grasslands are lacking. It is known that land management can improve performances of plants and ecosystem functions. Yet, the relative importance and potential of land management in buffering the negative impacts of climate change are largely unknown. In addition, the rain-out shelters used to study the ecological responses to climate change (mainly drought) are often criticized for creating micro-climatological artifacts, which may influence plant responses. Thus, the main objectives of this thesis were (a) to investigate how selected plants and ecosystems respond to different aspects of climate change (e.g. seasonal warming, precipitation variability, winter rain addition, late frost, heavy rainfall and drought), (b) to investigate three potential land management options to buffer the negative impacts of climate change, and (c) to contribute to the advancing of climate change research by examining whether there are any methodological artifacts in ongoing climate manipulations experiments. To meet these three objectives, responses (mainly related to phenology, productivity, physiology, seedling emergence and N status) of selected plant species, their populations, artificial plant communities as well as a semi-natural managed temperate grassland ecosystem were investigated. Seasonal (winter/summer) warming advanced flowering phenology and altered biomass production of early vs. late flowering species (manuscript 1). Onset of early flowering temperate grassland species was advanced by winter warming (4.9 days) more than by summer warming (2.3 days), while late flowering species were generally less sensitive to warming in either season. Flowering phenology was largely unaffected by experimental changes in precipitation regimes (manuscript 1). However, high precipitation variability during the growing season altered plant cover of early vs. late flowering species. Ecosystem productivity and legume facilitation increased under heavy rainfall compared to control (manuscript 2). Drought reduced plant physiological activities e.g. lower stomatal conductance, lower effective quantum yield, and lower leaf water potential (manuscript 6). Drought effects on plants were altered by the presence of legume species (manuscript 2). Under drought, the presence of a legume species enhanced overall biomass production of three neighboring grassland species by 36% compared to the absence of legume. Species-specific legume facilitation effects were also detected: Arrhenatherum elatius was facilitated by legume presence under drought and heavy rainfall, Plantago lanceolata was facilitated only under heavy rainfall, and Holcus lanatus was facilitated only under control conditions. Positive effects of legume presence found under control also persisted under drought for plant and soil N. European populations/provenances of grass species differed in plant N status under drought. Yet, populations from the wetter sites did not perform worse than presumably drought-adapted populations, indicating no evidence of local adaptation (manuscript 3). Variation in within-species responses was as high as variation in among-species responses under drought and late frost (manuscript 5). Within-species variation during the early life stages of Verbascum thapsus populations (a global plant invader) was detected as different germination and seedling emergence rates under the representative climates of seven biomes (manuscript 4). Furthermore, plant N status was altered by rewetting and harvest delay after drought (manuscript 3). Harvest delay after rewetting could not compensate the negative effects of drought on biomass production, but increased plant N concentration and N content. A detailed quantification of micro-climatological artifacts showed that the strength of drought manipulation using the rain-out shelter technique was dependent on ambient weather conditions (manuscript 6). Plant responses were highly correlated to ambient micro-climate conditions. Therefore, relating drought responses to ambient micro-climatological parameters such as air temperature and vapor pressure deficit can facilitate meaningful interpretation and comparison of studies and of different responses of experimental droughts between years within single studies. Furthermore, rain-out shelters altered temperature and reduced radiation inside the shelter. However, these micro-climatological artifacts had no significant effects on growth responses of grassland plants. Thus, fixed rainout shelters remain a useful tool for ecological drought manipulation experiments. In summary, the present thesis provides evidence on how climate change affects selected plant species and ecosystem functions in managed temperate grasslands. The findings of this thesis have practical implications for grassland ecosystem management in the face of climate change. For instance, negative drought effects can be minimized by legume presence and by rewetting combined with harvest delay. Results show strong differences in population-specific responses to extreme climatic conditions. However, climatic origin of populations cannot predict these response variations. Therefore, increasing within-species diversity (or population mixtures) may help maintain plant productivity and N nutrition in the face of climate change

Disentangling climate from soil nutrient effects on plant biomass production using a multispecies phytometer

Plant community biomass production is co-dependent on climatic and edaphic factors that are often covarying and non-independent. Disentangling how these factors act in isolation is challenging, especially along large climatic gradients that can mask soil effects. As anthropogenic pressure increasingly alters local climate and soil resource supply unevenly across landscapes, our ability to predict concurrent changes in plant community processes requires clearer understandings of independent and interactive effects of climate and soil. To address this, we developed a multispecies phytometer (i.e., standardized plant community) for separating key drivers underlying plant productivity across gradients. Phytometers were composed of three globally cosmopolitan herbaceous perennials, Dactylis glomerata, Plantago lanceolata, and Trifolium pratense. In 2017, we grew phytometer communities in 18 sites across a pan-European aridity gradient in local site soils and a standardized substrate and compared biomass production. Standard substrate phytometers succeeded in providing a standardized climate biomass response independent of local soil effects. This allowed us to factor out climate effects in local soil phytometers, establishing that nitrogen availability did not predict biomass production, while phosphorus availability exerted a strong, positive effect independent of climate. Additionally, we identified a negative relationship between biomass production and potassium and magnesium availability. Species-specific biomass responses to the environment in the climate-corrected biomass were asynchronous, demonstrating the importance of species interactions in vegetation responses to global change. Biomass production was co-limited by climatic and soil drivers, with each species experiencing its own unique set of co-limitations. Our study demonstrates the potential of phytometers for disentangling effects of climate and soil on plant biomass production and suggests an increasing role of P limitation in the temperate regions of Europe