Social-ecological and institutional factors affecting forest and landscape restoration in the Chittagong Hill Tracts of Bangladesh

Bangladesh government has recently pledged to restore 0.75 million ha of degraded forestland as part of its commitment to the Bonn Challenge, however little is known about the potential challenges and opportunities involved in achieving that goal. Using secondary literature complemented by expert consultation and a field survey, we examined the outcomes and limitations of previous restoration programmes and identified key social, ecological and institutional aspects crucial for a successful forest restoration programme in the Chittagong Hill Tracts (CHT) of Bangladesh. The CHT region accounts for over a third of state-owned forests, and it supports a large part of the country's forest-dwelling ethnic populations, although most of the forestland is severely degraded. Our analysis revealed that past programmes had utilised participatory tree planting, horticulture and rubber-based agroforestry to restore degraded forestland and improve community livelihood in the CHT. However, past restoration programmes merely emphasised improving tree cover without considering the ecological functionality, biodiversity and carbon co-benefits of restored forests. The duration of these pro-grammes was also relatively short, and there was no clear plan for engaging local communities in the restoration activities beyond the programme period. Among other things, the local ethnic community's land rights issue remained unresolved and the participant's land ownership influenced their willingness to participate effectively in any restoration programme. Households with secured land rights had a more positive attitude towards participating in forestland restoration than those with unsecured land rights. Suitable acts and policies that would allow people to legally continue to use tree-based land in the regions (i.e. forest and land tenure rights) are also lacking. Future forest and landscape restoration (FLR) programmes may thus need to focus on improving the biodiversity and ecological functionality of those restored forests, resolving local people's forest and land tenure rights and involving them in site-specific restoration interventions. The engagement of local and regional-level multi-stakeholders in such an FLR programme is also essential for realising the restoration's multiple social and ecological benefits

Edge influence on vegetation at natural and anthropogenic edges of boreal forests in Canada and Fennoscandia

Although anthropogenic edges are an important consequence of timber harvesting, edges due to natural disturbances or landscape heterogeneity are also common. Forest edges have been well studied in temperate and tropical forests, but less so in less productive, disturbance-adapted boreal forests. We synthesized data on forest vegetation at edges of boreal forests and compared edge influence among edge types (fire, cut, lake/wetland; old vs. young), forest types (broadleaf vs. coniferous) and geographic regions. Our objectives were to quantify vegetation responses at edges of all types and to compare the strength and extent of edge influence among different types of edges and forests. Research was conducted using the same general sampling design in Alberta, Ontario and Quebec in Canada, and in Sweden and Finland. We conducted a meta-analysis for a variety of response variables including forest structure, deadwood abundance, regeneration, understorey abundance and diversity, and non-vascular plant cover. We also determined the magnitude and distance of edge influence (DEI) using randomization tests. Some edge responses (lower tree basal area, tree canopy and bryophyte cover; more logs; higher regeneration) were significant overall across studies. Edge influence on ground vegetation in boreal forests was generally weak, not very extensive (DEI usually < 20 m) and decreased with time. We found more extensive edge influence at natural edges, at younger edges and in broadleaf forests. The comparison among regions revealed weaker edge influence in Fennoscandian forests. Synthesis. Edges created by forest harvesting do not appear to have as strong, extensive or persistent influence on vegetation in boreal as in tropical or temperate forested ecosystems. We attribute this apparent resistance to shorter canopy heights, inherent heterogeneity in boreal forests and their adaptation to frequent natural disturbance. Nevertheless, notable differences between forest structure responses to natural (fire) and anthropogenic (cut) edges raise concerns about biodiversity implications of extensive creation of anthropogenic edges. By highlighting universal responses to edge influence in boreal forests that are significant irrespective of edge or forest type, and those which vary by edge type, we provide a context for the conservation of boreal forests. Edges created by forest harvesting do not appear to have as strong, extensive or persistent influence on vegetation in boreal as in tropical or temperate forested ecosystems. We attribute this apparent resistance to shorter canopy heights, inherent heterogeneity in boreal forests and their adaptation to frequent natural disturbance. Nevertheless, notable differences between forest structure responses to natural (fire) and anthropogenic (cut) edges raise concerns about biodiversity implications of extensive creation of anthropogenic edges. By highlighting universal responses to edge influence in boreal forests that are significant irrespective of edge or forest type, and those which vary by edge type, we provide a context for the conservation of boreal forests

Clone Configuration and Spatial Genetic Structure of Two Halophila ovalis Populations With Contrasting Internode Lengths

Fine-scale spatial genetic structure (SGS) is predominantly determined by gene flow. While sexually reproducing plants can disperse their genes through pollen and seed grains, clonal plants can additionally disperse genes through clonal growth. Plants' clonal reproduction strategy, however, often varies within and between species. Still, the effect of differential clonal reproduction strategy on fine-scale SGS remains somewhat unclear. Halophila ovalis is a fast-growing clonal seagrass, whose internode length (which defines a species' clonal reproduction strategy) varies among populations. Using eight polymorphic microsatellites, here we compare the genetic diversity, clonal structure and fine-scale SGS of two H. ovalis populations with contrasting internode lengths (Yingluo vs. Xialongwei populations). We found moderate to high genotypic and allelic richness and heterozygosities in both populations. Compared to Xialongwei population, genetic and genotypic diversity was significantly lower in Yingluo population. Although their internode length was relatively short, clones of Yingluo population spread farther than those of Xialongwei population. Sexual-to-vegetative dispersal variance ratios were 34.6 and 445.5 in Yingluo and Xialongwei populations, respectively. In both populations, clonal growth significantly intensified the SGS, especially in short distance classes. The SGS at small distance classes were weaker in Yingluo than Xialongwei, in part, due to more intermingled distribution of genets and more extensive clonal expansion in the former population. Our results indicate that vegetative dispersal variance/distance, rather than internode length, plays a crucial role in shaping the fine-scale genetic structure

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

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background Disorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021. Methods We estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined. Findings Globally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer. Interpretation As the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed. Funding Bill & Melinda Gates Foundation

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Ecological Processes in a Spatially and Temporally Heterogeneous Landscape: a Study on Invasive Alliaria Petiolata

The dynamics of ecological populations and communities are predominantly governed by three ecological processes, environmental filtering, species interactions and dispersal, and these processes may vary with heterogeneity of the environment. In my PhD research, I investigated how ecologists conceptualize landscape heterogeneity, and how these three ecological processes may vary with spatial and temporal environmental heterogeneity. I conducted my empirical work in Alliaria petiolata, a non-native invasive species in North America, at the Koffler Scientific Reserve at Joker’s Hill in Ontario, Canada. The thesis contains six chapters, where chapters 2 – 5 are structured as stand-alone manuscripts. In chapter 2, I conducted a quantitative review to link the metacommunity concept (which combines the above-mentioned three processes) with different conceptual models of landscape spatial heterogeneity. I found that 78% of metacommunity studies were not explicit about the underlying model of landscape heterogeneity, though there was a significant association between the implied model of landscape heterogeneity and the observed metacommunity model. In chapter 3, I quantified dispersal of Alliaria petiolata, assessed the spatial structure of rosette and adult density, and compared the effects of the different processes on rosette and adult density. Seed dispersal followed a lognormal distribution (μ = 0.01, σ = 0.65). Both adults and rosettes exhibited significant spatial structure up to 2 m. Propagule pressure and interactions among life stages were significant processes shaping rosette density, whereas propagule pressure was the only important process shaping adult density. In chapter 4, I investigated patterns, determinants and demographic consequences of herbivory in A. petiolata. I found that patterns, determinants and demographic consequences of herbivory may vary between life stages and habitat types. One striking finding was that herbivory incidence in A. petiolata may strongly depend on plant life stage, possibly due to a defense–fitness trade off. In chapter 5, I tested whether intra-specific interactions in A. petiolata shift with temporal environmental heterogeneity (seasonality). I found significant negative density-dependent survival in summer and positive density-dependent survival over winter. I suggested that predictions of the stress gradient hypothesis at the intra-specific level are applicable to seasonal variation in environmental stress.Ph

Spatial structure in invasive Alliaria petiolata reflects restricted seed dispersal

This is the accepted manuscript of an article published by Springer Verlag.Identification of processes that shape the spatial structure of invasive species has important implications for understanding population regulation. In invasive Alliaria petiolata we quantified (i) spatial scale of seed dispersal under field conditions, (ii) spatial structure of rosette and adult density and (iii) the relative importance of environmental filtering, propagule pressure and adult-rosette interactions in shaping rosette and adult density. We conducted a seed dispersal experiment under field conditions; and in a three year field survey we measured quadrat-level rosette and adult density, adult seed production and soil moisture and light along transects in three A. petiolata populations at Koffler Scientific Reserve in Southern Ontario, Canada. Propagule pressure was estimated based on quadrat-level seed production and neighbourhood seed production. We found that seed dispersal of A. petiolata followed a lognormal distribution with a mean dispersal distance of 1.82 m, and that spatial structure in both adults (Moran’s I: 0.30 – 0.56) and rosettes (0.48 – 0.57) was significant up to 2 m. Propagule pressure and adult rosette interactions were significant processes associated with rosette density, whereas propagule pressure was the most important process associated with adult density. However, due to the observational nature of the data, it is difficult to determine whether the observed negative association between adult and rosette density is related to competition or to temporal variation in density-dependent seed production. Overall, we conclude that spatially restricted seed dispersal is the most important factor underlying this species’ patchy distributions.This is a publication of Koffler Scientific Reserve at Jokers Hill. The study was supported by a NSERC discovery grant to HHW

Appendix A. List of plant functional traits considered in this study with their surrogate functions.

List of plant functional traits considered in this study with their surrogate functions