Tropical Dry Forest Ecosystem Research Articles

Impact of fire-burn on soil geochemical, microbial biomass and carbon stocks in a dry tropical forest ecosystem

Impact of fire-burn on soil geochemical, microbial biomass and carbon stocks in a dry tropical forest ecosystem

Mapping of soil carbon balances changes in the dry tropical forest ecosystem in Pernambuco Brazil

Maps of soil and vegetation carbon stock dynamics resulting from changes in land use in tropical dry areas are still scarce and virtually absent for the Brazilian Northeast region. The few data available were built on a scale that does not allow their use for decision-making and precision farming applications. Based on soil and land use data, we developed a geographical information system to estimate and map carbon balances in the large (86.135 km2) semiarid region of Pernambuco state, Brazil. Maps of carbon stocks for soil and vegetation for the years 2000 and 2016 were created on the scale of 1: 100000, stratified by land use and soil types. In this period, 28% of the area had decreases in soil and vegetation C stocks, 57% had no significant changes and only 13% had increases. Most of the change was associated with converting the open native forest vegetation (Caatinga) into pastures. The net C loss was 291 million Mg, representing an average loss of 2 Mg C ha-1 year-1. Water bodies, urban areas, and other unclassified uses were not accounted for but amounted to only 2% of the area. Overall, the method proved to be a fast and feasible approach to monitoring carbon balances derived from land use changes on a regional scale.

Diversity of an Odonata assemblage from a tropical dry forest in San Buenaventura, Jalisco, Mexico (Insecta, Odonata).

The patterns of richness, diversity, and abundance of an odonate assemblage from San Buenaventura, Jalisco are presented here. A total of 1087 specimens from seven families, 35 genera and 66 species were obtained through monthly samplings of five days each during a period of one year. Libellulidae was the most diverse family (28 species), followed by Coenagrionidae (21), Gomphidae (7), Aeshnidae (6), Calopterygidae (2), Lestidae (1) and Platystictidae (1). Argia was the most speciose genus. The highest species richness and Shannon diversity were found during August and September, whereas the highest abundance was observed in June and the highest Simpson diversity was recorded in September - all of which were associated with the rainy season. The highest values of phylogenetic diversity were found from June to October. The different diversity facets of this assemblage were positively correlated with precipitation and minimum temperature, whereas maximum temperature showed no influence. In addition, we found that this odonate diversity was higher than most Mexican localities with tropical dry forest (TDF) studied. We continue our efforts to describe the patterns of richness, diversity and abundance of some insect groups associated with the tropical dry forest ecosystem in Mexico, following a latitudinal gradient of the distribution of this ecosystem in the country. Our emphasis here was to evaluate the spatial and temporal patterns of richness and diversity of an Odonata assemblage from Jalisco, Mexico.

Variations in the plasticity of functional traits indicate the differential impacts of abiotic and biotic factors on the structure and growth of trees in tropical dry forest fragments

Abiotic and biotic factors have considerable impact on the plasticity of plant functional traits, which influences forest structure and productivity; however, their inter-relationships have not been quantified for fragmented tropical dry forest (TDF) ecosystems. We asked the following questions: (1) what are the variations in the plasticity of functional traits due to soil moisture availability in TDF fragments? (2) what are the roles of soil nutrients and forest disturbances in influencing variations in the plasticity of functional traits in the TDF fragments? and (3) how do the variations in the plasticity of functional traits influence the structure and productivity of TDF fragments? Based on linear mixed-effects results, we observed significant variations among tree species for soil moisture content (SMC) under the canopy and selected functional traits across forest fragments. We categorized tree species across fragments by principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) analyses into three functional types, viz., low wood density high deciduous (LWHD), high wood density medium deciduous (HWMD), and high wood density low deciduous (HWLD). Assemblage of functional traits suggested that the LWHD functional type exhibits a drought-avoiding strategy, whereas HWMD and HWLD adopt a drought-tolerant strategy. Our study showed that the variations in functional trait plasticity and the structural attributes of trees in the three functional types exhibit contrasting affinity with SMC, soil nutrients, and disturbances, although the LWHD functional type was comparatively more influenced by soil resources and disturbances compared to HWMD and HWLD along the declining SMC and edge distance gradients. Plasticity in functional traits for the LWHD functional type exhibited greater variations in traits associated with the conservation of water and resources, whereas for HWMD and HWLD, the traits exhibiting greater plasticity were linked with higher productivity and water transport. The cumulative influence of SMC, disturbances, and functional trait variations was also visible in the relative abundance of functional types in large and small sized fragments. Our analysis further revealed the critical differences in the responses of functional trait plasticity of the coexisting tree species in TDF, which suggests that important deciduous endemic species with drought-avoiding strategies might be prone to strategic exclusion under expected rises in anthropogenic disturbances, habitat fragmentation, and resource limitations.

Co-occurrence of climate-change induced and anthropogenic pressures in Central American key biodiversity areas

Central America hosts many key biodiversity areas (KBAs), areas which represent unique and irreplaceable ecosystems of global importance for species conservation. However, large extents of these areas are not under legal protection and could be threatened by pressures from land use change (e.g. deforestation and agricultural expansion), high human population density (e.g. population growth and urban sprawl) and climate-driven biome shifts. Here, we simulated future biome stability under the influence of climate change across KBAs in the Mesoamerican biodiversity hot spot and combined the results with projections of land use and population density up to the end of the 21st century. We applied four forcing scenarios based on two global climate models (GFDL-ESM4 and IPSL-CM6A-LR) and two shared socio-economic pathways (SSP1-2.6 and SSP3-7.0), which represent a range from low to high emission pathways. Our model projected decreased biome stability in 39%–46% of protected areas in KBAs, whereas this number even increased to 59%–60% for unprotected areas in KBAs (depending on the climate scenario). While human interferences in protected parts of KBAs are expected to be limited, large parts of unprotected areas in KBAs were projected to be pressured by multiple factors at once and are reason for concern. In particular, high human population pressures (>10 people km−2) emerged as a main threat over 30%–44% of the unprotected area in KBAs. These were largely accompanied by pressures from land use and sporadically reinforced by pressures from climate-driven biome shifts. Among the hot spots facing multiple high pressures are some of the last tropical dry and montane forest ecosystems in Central America, which stresses the need for urgent conservation action.

Recurrent forest fires, emission of atmospheric pollutants (GHGs) and degradation of tropical dry deciduous forest ecosystem services

Forest fires threaten to biodiversity, ecosystem productivity, multiple ecosystem services, and it influences the emissions of large amounts of greenhouse gases into the atmosphere. This scientific study has been conducted at Ayodhya hill range of dry deciduous forest of Chota Nagpur plateau (India).The principal objectives of this research are (1) to measure the terrestrial ecosystem productivity by Vegetation Photosynthesis Model (VPM); (2) to estimate the greenhouse gases (GHGs) emission through forest fire following IPCC guidelines; and (3) to quantify the ecosystem service value and degradation of ecosystem services (ESs) by specific indices and focus group discussions (FGDs). Results show that biophysical, climatic and environmental factors notably affect the growth of ESs. A significant reduction of net primary production (NPP) and biomass has been measured in fire month (100.71 and 223.59 gC m−2 month−1) and values of spectral indices also show negative trend during fire month (-0.1279 to −0.2104) respectively. Total 294.15 g, 1.44 g, 21.03 g, 0.0099 g and 0.0231 g of CO2, CH4, CO, NO2, and NOX have been emitted respectively through forest fire from this hill range during forest burning period (March 2021). This study also revealed that average (18.50%) forest dependency or relative forest income (RFI) has been fallen in the recent years due to recurrent forest fires, execution of different developmental works and deforestation. The effective management of forest resources (through payment for ESs and willingness to pay approaches) is highly necessary in strengthening the rural economy and welfare of indigenous tribal people.

Distribution of the northern pampas cat, Leopardus garleppi, in northern South America, confirmation of its presence in Colombia and genetic analysis of a controversial record from the country

Abstract The common name of pampas cat includes a complex of small Neotropical felid species found in various habitats of South America. Recently several species of this complex were proposed, but there are few records in the northernmost distribution of the continent, and reports of the pampas cat’s presence in Colombia have been ambiguous. Current northern limits of Leopardus garleppi are limited to the Andes of Ecuador. Here we present the northernmost record of the species, validating its presence in Colombia and review previous controversial records from the country. The new record is based on a road-killed specimen in a dry tropical forest ecosystem in the municipality of Mercaderes, Department of Cauca. Our morphological and genetic comparisons also shown that a previous record from Colombia supported by a single skin recently used to described a new species named Leopardus narinensis belong to Leopardus tigrinus. With the information compiled from new localities in Colombia and Ecuador, the known distribution range for L. garleppi is increased towards the northern part of South America into areas of Tropical Dry Forest. The distribution now includes 14 ecoregions from Colombia to Bolivia, and four in Colombia (Eastern Cordillera real montane forests, Northwestern Andean montane forests, Northern Andean paramo, and the Patía Valley dry forests), which correspond to similar ecosystems inhabited by the species in other Andean landscapes. The potential distribution hypothesis showed that the species has high suitability in large areas of southwestern Colombia (Nariño). With the recording of L. garleppi in Colombia, the number of extant felid species in the country has increased to seven.

Amount and Vertical Distribution of Soil Organic Carbon and Total Nitrogen in a Dry Tropical Forest Ecosystem, Tanzania

There is a growing interest in understanding soil organic carbon (SOC) and total nitrogen (TN) of various ecosystems worldwide, because they are important indicators of soil quality and soil fertility, especially on the availability of essential nutrients for plant growth; and climate change mitigation. We tested the hypothesis that the amount and vertical distribution of SOC and TN in 0-30cm and 30-100cm depths differ significantly in miombo woodland ecosystems. Soil samples were collected from 15m-radius circular plots (n=33). SOC was determined by Mid-Infrared (MIR) spectroscopy (ICRAF approach) and the Walkley and Black method (NAFORMA approach). The mean amount of SOC and TN at 30-100cm depth were significantly higher (<i>p</i>=0.003 and <i>p</i>=0.0001, respectively) than that within the 0-30cm depth. The amount of SOC at 20-40cm (39tCha^-1) was found to be significantly (<i>p</i>=0.0007) higher than at 0-20cm (32tCha^-1) followed by decreasing pattern to 100cm. On the other hand, TN decreased substantially from 0-20cm to 100cm depth. SOC was significantly (<i>p</i><0.05) and positively correlated with TN. The NAFORMA approach estimated significantly (<I>P</I><<i>0.05</i>) higher SOC than ICRAF approach. Clearing of forests for sesame cultivation invariably resulted in increased nitrogen in the top soil due to addition of ammonium fertilizers, but loss of SOC is due to removal of biomass (including slash burning) and a reduction in the quantity and quality of organic inputs added to the soil. Accurate estimation of SOC at national and regional scales should use the modern methods complimented by the standard methods in different ecosystems.

Rarity and conservation status of the Colombian Speckled Tree Rat, Pattonomys semivillosus (I. Geoffroy, 1838)

Abstract The Colombian Speckled Tree Rat, Pattonomys semivillosus, is a little-known rodent endemic to the Lower Magdalena River basin at the Caribbean Coast of Colombia. To date it is the only species of Pattonomys documented in the country. We provide information on the rarity, and conservation status of P. semivillosus based on the current and potential distribution, population density and size using information from the literature, new records, and museum vouchers. We confirmed 66 occurrences that belong to 25 localities in six departments (Atlántico, Bolívar, Cesar, La Guajira, Magdalena, Santander, and Sucre) in northern Colombia, including 18 new localities not previously reported in the literature, mostly in the highly threatened Tropical Dry Forest ecosystem. The population density in three sites of Department of Cesar was 5.4 ind/km2, 5.9 ind/km2, and 32.4 ind/km2. The species matches with the Category D of rarity, and we suggest an update to the threatened assessment (from Least Concern to Near Threatened). This information will contribute to update the current IUCN assessment of the species.

Biodiversity conservation and carbon storage of Acacia catechu willd. Dominated northern tropical dry deciduous forest ecosystems in north-western Himalaya: Implications of different forest management regimes

Sustainable forest management is the key to biodiversity conservation, flow of resources and climate change mitigation. We assessed the impact of various forest management regimes (FMRs): legal felling series [(reserve forest (RF), demarcated protected forest (DPF), un-demarcated protected forest (UPF), co-operative society forest (CSF) and un-classed forest (UF)] on biodiversity conservations and carbon storage in Acaciacatechu Willd. Dominated northern tropical dry deciduous forest ecosystems in Nurpur Forest Division of north-western Himalaya, India. The study revealed significant variations in floristic composition, biodiversity indices, population structure and C storage potential among different forest management regimes. The RF and DPF were found to be rich in species diversity and richness whereas the Simpson dominance index for trees and shrubs was maximum in UF and UPF, respectively. The diversity of understory herbs were higher in CSF and UF. The maximum density of seedlings, saplings and poles were recorded in RF followed by DPF and UPF, whereas the minimum density was found in CSF. The tree C density (69.15 Mg C ha−1) was maximum in UF closely followed by RF; whereas the minimum was recorded in CSF (33.27 Mg C ha−1). The soil C density was maximum in RF (115.49 Mg C ha−1) and minimum in CSF (90.28 Mg C ha−1). Similarly, the maximum total ecosystem C density was recorded in RF (183.52 Mg C ha−1) followed by DPF (166.61 Mg C ha−1) and minimum in CSF (126.05 Mg C ha−1). Overall, UF management regimes were shown to have a greater capacity for C storage in vegetation, whereas strict FMRs, such as RF and DPF, were found to be more diverse and have a higher soil and ecosystem carbon density. The study established that in the midst of climate and biodiversity emergencies, it is urgent to maintain, protect and strengthen the network of RF and DPF FMRs for biodiversity conservation, climate change adaptation and mitigation.

The Potential Effect of Climate Change on the Distribution of Endemic Anurans from Mexico’s Tropical Dry Forest

Mexico is one of the richest countries in amphibian species (420 spp.), with a high level of endemism (69%). The order Anura represents the most diverse and widespread of the three extant amphibian orders (257 spp.). The anurofauna of Mexico’s tropical dry forest ecosystem host a high proportion of the species and endemism registered in the country. In terms of conservation, both dry forests and amphibians are at risk due to climate change because it is expected that as the temperature becomes higher and precipitation decreases, this vegetation type may experience water stress. We applied the MaxEnt algorithm to estimate the potential current and future (year 2070) geographic distribution patterns of 95 endemic Mexican anuran species inhabiting the country’s tropical dry forests by considering two representative concentration pathway scenarios (RCP4.5/RCP8.5) and analyzed the potential distributional pattern changes. The results indicated that overall, species would experience enough of a significant warming effect to cause a reduction in the original distribution area, with 44% of species losing an average of 50% of their original range (9 spp. in threatened category); additionally, 22% of the species in the dry forest ecosystem will experience an average increase of almost 50% in their original area, two species will lose more than 80% of their range, and one will disappear.

Opportunities for Integrating Social Science into Research on Dry Forest Restoration: A Mini-Review

Seasonally dry tropical forest ecosystems have been greatly reduced in areas through conversions to alternate land uses such as grazing and crop production. The U.N. Decade on Restoration has focused attention on both restoration globally, and also regional attention on tropical dry forests, as they are excellent candidates for regeneration and reforestation. As such, the science of how we restore dry forests is advancing; however, few studies of dry forest restoration include collaborations with social scientists. This is unfortunate, because restoration projects that embrace a people-centered approach have the highest chances of success. Here, I review recent studies that have incorporated aspects of social science and human dimensions into the study and design of dry forest restoration practices. I focus on three key topics that merit a closer integration of restoration research and practice and social science: (1) recognizing that local people are central to project success, (2) cost benefit or effectiveness analyses that evaluate the relative costs of alternative management strategies, and (3) identification of land-use tradeoffs, synergisms and priority mapping. I conclude that closer collaborations among dry forest restoration researchers and a wider group of partners including social scientists, local communities, environmental educators, and geographers will increase the value of restoration research and the likelihood that such projects achieve multiple ecological and societal benefits.

HERB DIVERSITY AND THEIR MEDICINAL USES IN BIODIVERSITY CONSERVATION AREA OF JNANABHARATI CAMPUS, BANGALORE UNIVERSITY, KARNATAKA

Unnoticed, breeding beneath the canopy in the woods, the herb layer serves a special role in maintaining the structure and function of forests, this stratum remains an underappreciated aspect of forest ecosystems. The Bangalore University, Jnanabharathi campus, historically being a scrub forest facilitating the growth of enormous vegetation ranging from large canopied trees to understory layer comprising of herbs and grasses. The present study was intended to assess the herbs diversity, richness and medicinal use to emphasize its role in tropical dry forest ecosystems, using a quadrate method. A total of 61 species were recorded, comprising of 52 species of herbs, representing 28 families, of which (77%) belongs to native and (23%) exotic (non-native) category. In addition to herbs four species of grass and five climber species of procumbent were also recorded in the same quadrate. Desmodium triflorum with1014 individuals and (IVI = 11.76) was found to be dominant species followed by Evolvulus alsinoides, Vicoa indica and Calyptocarpus vialis. Astraceae and Fabaceae was the most abundant family followed by Lameaceae and Acanthaceae. The diversity indices were estimated to determine the richness, diversity and evenness of herbaceous species, among three sectors, sector-1 is found to have Shannon index of 3.14 and Simpson index of 0.95, where highest Evenness index of 0.64 was associated with sector-3 followed by Sector-8 and Sector-1. From the study it was also revealed that all the three sectors were significantly depicting clumped or contagious pattern of herb distribution. The study indicates that understory herbaceous layer plays very important role in regeneration of canopy species in scrub forest and it support regeneration of many medicinal herbs. Hence University authorities should protect herb layer from fire, grazing and other anthropogenic disturbances.

Agricultural Land-Use Increases Floral Species Richness in Tropical Dry Forest and Savannah Ecosystems in West Africa

The diversity and structure of plant communities are valuable indicators for assessing landscape quality. Land-use change is one of the main factors considered to affect and have the strongest impacts on biodiversity. In this study, we assessed the effects of the conversion of tropical dry forests and savannahs into agricultural lands on the floral diversity and the structure of the vegetation. For this purpose, we carried out vegetation surveys in 198 plots of 50 m × 50 m. Within each plot, we documented all herbaceous, shrubby, and tree species present. We calculated total, spatial, and local floral diversities by land-use types and characterized the structure of the plant communities. Our results show that the overall floral diversity of the study area remains quite high (483 species of vascular plants from 298 genera and 71 families) and was not strongly impacted by agricultural land use (Pareto inequality index is 23–77). Croplands had the highest spatial (9.4) and local diversities. There was no significant difference between the land-use types in terms of the native species richness while croplands harbored significantly the most alien species. Agricultural land use significantly affected the structure of the plant communities. Trees are very rare in croplands and are frequent in forests and savannahs. The clearing of Guinean dry forests and savannahs for cropping did not automatically lead to a loss of some aspects of ordinary floral diversity. For a better understanding of the effects of land-use change on biodiversity, it would then be more suitable to specify in the studies whether the species concerned are native, alien, generalist, or specialist.

Carbon sequestration potential and CO2 fluxes in a tropical forest ecosystem

Carbon (C) is a key product of forests, but not widely studied for available C stock, and biomass of tree species in typical forest ecosystems of India. Therefore, it is useful to estimate C stock at national and regional levels for establishing forest-based policies and developing roadmap for long-term plans and strategies to reduce the rate of increase of atmospheric carbon dioxide (CO2). Hence, present investigation was conducted to assess C storage and CO2 fluxes in tropical dry deciduous forest ecosystems of Jhumpa and Kairu in the southern Haryana, India. The C stock of trees in above ground biomass (AGB) was calculated by assuming the C content at 50% of the total biomass. Concentration of C in composite samples of shoots and roots of shrubs and herbs was estimated by the ash method. Soil C storage was determined on the basis of C concentration and soil bulk density up to 60 cm depth. The AGB of trees ranged from 33.1 to 75.8 Mg ha−1; the belowground biomass from 9.0 to 18.5 Mg ha−1 and total plant C storage from 24.3 to 53.9 Mg C ha−1. The total biomass of shrubs was 16.2 Mg ha−1 for the Salvadora oleoides forest at Jhumpa compared with 8.4 Mg ha−1 for the Acacia senegal-Acacia tortilis forest at Kairu. Net primary productivity of various components of trees in these forest ecosystems ranged from 8.1 to 9.6 Mg ha−1 y−1 and net flux of C from 4.6 to 5.8 Mg C ha−1 y−1. The annual litter fall in two forest ecosystems ranged from 3356 to 4498 Kg ha−1. S. oleoides contributed 50.0% and 47.3% towards the above ground and below ground C pools corresponding to the 17.9 Mg C ha−1and 4.1 Mg C ha−1, respectively. S. oleoides played a dominant role in biomass production and C assimilation in S. oleoides-A. tortilis forest at Jhumpa, while Prosopis juliflora and A. senegal were the highest contributors in A. senegal-A. tortilis forest at Kairu because of a high girth class and high density of trees, respectively. The cumulative soil organic carbon (SOC) stock up to 60 cm depth was more in A. senegal-A. tortilis forest at Kairu (16.3 Mg C ha−1) than that in the SO-AT forest at Jhumpa (12.9 Mg C ha−1). The results of this study revealed that S. oleoides and P. juliflora are key species as they sequester more C under a range of disturbances. Carbon sequestration potential of the studied forest ecosystems was 3.55 to 4.35 Mg C ha−1 y−1 which indicates a high C sequestration potential of these ecosystems.

Herbaceous vegetation under planted woody species on coal mine spoil acts as a source of organic matter

The present study was conducted to examine the status of herbaceous biomass development under rehabilitated coal mine spoil by establishing indigenous woody species in India's northern dry tropical region. Since mining activities for coal and minerals are prime industrial activities in this region; therefore, through these activities, a significant size of dry tropical forest ecosystems is destroying at unprecedented rates. Thus, the primary objective of the present study was to understand the influence of planted woody species on herbaceous biomass development. Estimation of herbaceous biomass was accomplished once in 1995 and 2007 under plantation stand of four native woody species. Among planted woody species, maximum herbaceous biomass was quantified at the 5th-year stand of Tectona grandis and lowest at the 17th-year stand of Dendrocalamus strictus. Family Poaceae contributed the maximum in herbaceous biomass production across all plantation stands. A declining trend was observed in herbaceous biomass production as the age of plantation stand increases, reflecting the impact of stand characteristics such as woody species basal cover and canopy cover on herbaceous vegetation development. Herbaceous biomass was positively correlated with species diversity at both ages of plantation stands, emphasising the facilitative role of species for organic matter build-up in disturbed habitats. However, increased competition between herbaceous species for space, nutrients and decreased penetration of light through the closed canopy of planted woody trees significantly influences herbaceous diversity under plantation stand.

Comparison of Physico-chemical Properties of Soils under Different Forest Types in Dry Tropical Forest Ecosystem in Achanakmar-Amarkantak Biosphere Reserve, India

The present study was conducted to assess the variations in physico-chemical properties of soils under four forest types viz. Mixed Forest, Mixed Sal Forest, Mixed Teak Forest, and Teak Mixed Forests in a typical dry tropical ecosystem of Achanakmar-Amarkantak Biosphere Reserve (AABR), Central India. Soil samples were collected from four types of forest and analyzed for the soil samples were taken at three soil depths, i.e. at 0-20 cm, 20-40cm and 40-60 cm and analysed for pH, EC, Organic C, soil moisture, bulk density, nitrogen (N), phosphorous (P) and potassium (K). The pH of soil was lower (5.43) under Mixed Forest and higher (6.13) in Teak Mixed Forest, while EC in soil was lower (0.04 dS m-1) in Mixed Sal Forest and higher (0.32 dS m-1) under Teak Mixed Forest. Organic C varied from 11.5 Mg ha-1 to 17.8 Mg ha-1 at 0-20 cm soil depth which was highest in soil under Mixed Sal Forest and lowest in Teak Mixed Forest. The Organic C and EC values were decreased with an increase in soil depth, while the bulk density showed reverse trend. Soil nutrients in different depths varied between 160.2 -196.9 kg ha-1, 10.4-17.7 kg ha-1 and 266.4-439.1 kg ha-1 for N, P and K, respectively. The nutrient quantities in soil were higher in Mixed Sal Forest and lower under Teak Mixed Forest, which decreased with soil depth. The paper discusses the possible variations in soil properties in relation to structure and composition of forest type and suggests appropriate management practices for the sustainable development of forest soils in dry tropical ecosystem.

Biomass Production Assessment in a Protected Area of Dry Tropical forest Ecosystem of India: A Field to Satellite Observation Approach

In recent decades, degradation and loss of the world’s forest ecosystems have been key contributors to biodiversity loss and future climate change. This article analyzes plant diversity, biomass, carbon sequestration potential (CSP), and the net primary productivity (NPP) of four vegetation types viz., Dense mixed forest (DMF); Open mixed forest (OMF); Teak plantation (TP), and Sal mixed forest (SMF) in the dry tropical forest ecosystem of central India through remote sensing techniques together with physical ground observations during 2013–2018. The total C storage in trees varied from 16.02 to 47.15 Mg ha−1 in studied vegetation types with the highest in DMF and lowest in OMF. The total C storage in stem wood, branches, and foliage falls in the range of 52.93–78.30%, 9.49–22.99%, and 3.31–12.89% respectively. The total standing biomass varied from 83.77 to 111.21 Mg ha−1 and these variations are due to different vegetation types, with the highest in DMF followed by TP, SMF while the lowest was estimated in OMF. The net primary productivity (NPP) [aboveground (AG) + belowground (BG)] varied from 7.61 to 9.94 Mg ha−1 yr−1 with mean values of 8.74 Mg ha−1 yr−1 where AG shares a maximum contribution of 77.66%. The total biomass production was distributed from 64.09 to 82.91% in AG and 17.08–35.91% in BG components. The present study outlines that the studied forest ecosystem has the substantial potential of carbon sequestration and a great possibility of mitigating local and global climate change.

Pollination Biology of an Endemic Hawaiian Tree, Erythrina sandwicensis (Fabaceae: Papilionoideae), in a Novel Ecosystem1

Tropical dry forest ecosystems are among the most endangered ecosystems globally. In Hawai‘i, dry forest species are under threat due to habitat destruction, invasive species, and a loss of mutualisms including pollinators. Understanding the pollination biology of species at risk can inform conservation strategies. This study aimed to identify the breeding system and types of floral visitors to Erythrina sandwicensis (Fabaceae) or wiliwili, an iconic Hawaiian tree in decline and with little regeneration. We conducted hand-pollination trials and observed visitors in two sites: a botanical garden and a forest site. We compared fruit set, seed set, seed germination, seedling growth rate, and seedling size across four pollination treatments: open control, autogamy, geitonogamy, and xenogamy. We found that wiliwili is visited by a novel suite of non-native visitors. All treatments produced seeds, but the xenogamous (cross) treatment produced significantly more fruit and seeds than the control or other treatments. Seedlings produced from cross-pollinated treatments were also taller and had wider basal diameters after twenty-eight days of growth. These results indicate that wiliwili employs a mixed-mating system, and that trees are pollen limited. Enhancing current populations of wiliwili to promote cross-pollination could help increase population regeneration.

Canals as invasion pathways in tropical dry forest and the need for monitoring and management

Abstract Linear infrastructure intrusions are common around the world to meet the needs of a growing and interconnected human population. The implementation of linear infrastructures involves numerous forms and mechanisms of land‐use transformation that can facilitate and serve as pathways to the spread of invasive non‐native species. However, the type and intensity of land transformations change over time and this can affect the frequency and intensity in which linear infrastructures route the spread of invasive species. Here, we present results collected over 5 years of monitoring surveys (2015–2019) to assess the relationship between the construction of one of the largest canals to date in Brazil and the spread of non‐native species. We studied the Integration Project of the São Francisco River (PISF), a canal fully inserted in the Caatinga biome, a tropical dry forest ecosystem for which information on invasion dynamics are little known. Our results confirmed PISF canals served as habitat and dispersal corridors for non‐native plant species. Monitoring surveys recorded 26 non‐native species established along the 83.2 km2 PISF deployment area. Eleven years after the canal deployment area was completely cleared of vegetation, 92.3% of its extension had non‐native plant populations. Of the 10 species assessed for their population status, 8 had invasive populations. The time immediately after construction work finished was the critical stage for the spread of non‐native woody plants, which increased their distributions with reduced levels of construction intervention, whereas most of the herbaceous species reduced their distributions. When human intervention was drastically reduced, many populations of non‐native plants rapidly formed at the deployment area. Policy implications. Man‐made linear infrastructures can remove biogeographical barriers and serve as pathways for the spread of invasive species over long distances and across ecosystems. Thus, the planning, construction and management of such infrastructures should include measures and funding for risk assessment, prevention, monitoring and control of biological invasions. Agencies responsible for environmental licensing should mandate invasive species management as part of the installation and operation licensing conditions.