Search Results (120)

This study examines the spatio-temporal dynamics of Acacia auriculiformis in Lubumbashi city, southeastern Democratic Republic of Congo, in the context of rapid urbanization following the liberalization of the mining sector. The city has experienced significant demographic growth and unplanned spatial expansion, resulting in a decrease in vegetation cover. The introduction and proliferation of A. auriculiformis, an exotic tree species, have occurred without strategic planning or monitoring. Utilizing digitized remote sensing imagery from 2006, 2014, and 2021, we quantified the expansion of A. auriculiformis along the urban–rural gradient. Additionally, a floristic inventory conducted in 2021 provided insights into tree diversity within A. auriculiformis plantations. Our findings indicate a substantial increase in the number and area of A. auriculiformis patches, predominantly in urban zones. However, the patch values, highest in 2006, were shown to decline by 2021, especially in urban areas. The floristic inventory identified 39 tree species within A. auriculiformis plantations, including predominant species such as Albizia lebbeck, Albizia alba, and Leucaena leucocephala. Notably, 20 of these species are exotic, with half being invasive. In contrast, the 19 indigenous species were primarily found in peri-urban areas. While a greater number of tree species were observed in urban zones, larger average diameters were recorded in peri-urban zones. The persistence and expansion of A. auriculiformis in a landscape characterized by declining tree cover suggest its potential sustainability in this setting. However, A. auriculiformis plantations have facilitated the establishment of predominantly exotic and potentially invasive species. These findings highlight the need for the strategic management of A. auriculiformis and associated exotic flora to mitigate their spread and to consider their role in the restoration of degraded lands. Full article

Historically, 23 freshwater mussel species have been documented from the Buffalo National River (BNR), a 246 km, free-flowing river in northern Arkansas. The potential threats to BNR include land use/land cover changes, eutrophication, recreation, physical habitat changes, and various climate change-related effects. Twelve quantitative mussel bed sites were established and then sampled using a stratified random sampling protocol to evaluate the long-term changes between 2006 and 2020–2021 in population and assemblage characteristics. We compared (1) overall mussel bed persistence, sampling confidence levels and study-wide relative abundances, and compared species’ size and size-frequency distributions; (2) 10 overall site assemblage variables using paired t-tests; (3) site-level mean density, richness, and diversity indices using pair-wise Mann–Whitney U statistics; and (4) assemblage composition using Non-Metric Multidimensional Scaling. The major findings included the following: (1) sampling efforts based on a targeted 80% confidence level appears relatively robust, (2) BNR mussel assemblage composition and structure were relatively stable (however, small mussel bed persistence is a concern), (3) 7 of 23 sites were outliers based on freshwater mussel composition and habitat characteristics, and (4) assemblage composition changed with three species declining (Actinonaias ligamentina, Lasmigona costata, and Ptychobranchus occidentalis) and four species increasing (Cambarunio hesperus, Cyclonaias tuberculata, Eurynia dilatata, and Venustaconcha pleasii) between monitoring events. Full article

Anaxyrus microscaphus (The Arizona Toad) is an at-risk species that is endemic to the southwestern United States. Despite conservation concerns, little is known about the ecological drivers of its distribution and habitat use. We investigated the potential distribution of A. microscaphus at the range-wide scale and local scales (i.e., Zion National Park), using MaxEnt to model habitat suitability under current and future climate scenarios. Our models incorporated 12 environmental variables, including climatic, geomorphological, and remotely sensed data. The results showed good model accuracy, with temperature and elevation being the top contributing variables. Currently, 42.6% of the park’s area provides a suitable habitat for A. microscaphus, but projections for 2050 and 2070 indicate a significant reduction in suitable habitat across its range. Temperature was the most influential variable, with habitat suitability decreasing as the annual mean temperatures exceeded 10 °C. Precipitation, vegetation, and topography variables also significantly contributed to the models. The most suitable habitat within Zion National Park occurred along sloped rivers and streams and in valleys with sandy soils, emphasizing the importance of riparian habitat conservation for A. microscaphus survival and persistence. As climate change progresses, the species’ habitat is expected to become increasingly constrained across local and range-wide scales. Our models demonstrated a shift in the suitable habitat towards major river systems, indicating a potential reliance on larger permanent river systems as smaller, more ephemeral habitats decrease in size and abundance. Future management strategies should prioritize conserving and enhancing the resilience of these habitats. MaxEnt models can guide population survey efforts and facilitate the identification of priority conservation areas, saving time and resources for species of concern such as A. microscaphus. Further research, including field surveys and large-scale analyses, is necessary to further refine our understanding of this species’ distribution and how it may be impacted by climate and habitat change. Full article

The relationship between plant productivity, measured according to biomass and species richness, is a fundamental focal point in community ecology, as it provides the basis for understanding plant responses or adaptive strategies. Although studies have been conducted on plant biomass and environmental factors, research concerning mountainous grassland areas is scarce. Therefore, the aim of the present study was to examine the influence of environmental factors on aboveground plant biomass in the mountainous grassland of the Mountain Zebra National Park, South Africa. Biomass distribution was uneven within the park, owing to certain species having relatively higher biomass values. These differences may be attributed to the chemical and physical properties of the soil, including carbon and nitrogen content, soil pH, and soil texture (sand, silt, and coarse fragments). A disc pasture meter was used to collect biomass data. Multiple regression analysis revealed that most environmental factors did not significantly influence plant biomass. The only environmental factor influencing plant biomass was soil pH; the influences of other factors were not statistically significant. The results of this study elucidate the interactions of environmental factors with plant biomass. Future research could investigate how environmental factors influence plant biomass, both below and above the ground in mountainous grassland. Full article

Translocation of endangered plant species and facilitating in situ regeneration require knowledge of the factors that define suitable habitat characteristics. Four approaches were employed to define how antecedent and contemporary plant identity influenced Cycas seedling growth and survival in Guam, Yap, and the Philippines. Cycas micronesica K.D. Hill or Cycas nitida K.D. Hill & A. Lindstr. seedlings growing beneath the canopy of the maternal parent tree reached 100% mortality in 4 to 8 year. Cycas micronesica seedlings planted beneath a conspecific male adult tree reached 68% mortality in two years while seedlings planted away from a conspecific individual exhibited 100% survival. Cycas micronesica seedlings planted beneath monostands of invasive Leucaena leucocephala (Lam.) de Wit or Vitex parviflora Juss. reached 40% mortality in two years while seedlings planted in adjacent native forest cover exhibited 100% survival. Cycas micronesica seedlings planted in soil conditioned for 9 months by conspecifics, heterospecific native species, Carica papaya L., L. leucocephala, or V. parviflora exhibited the greatest growth in the soils conditioned by heterospecific natives and the least growth in the soils conditioned by the three invasive species. The seedlings growing in soil conditioned by conspecifics exhibited the most coralloid roots and the greatest shoot:root ratio. These studies confirmed that the identity of antecedent and competitive plants strongly influenced the longevity and growth of Cycas seedlings. Conservationists may improve outcomes by avoiding degraded forests that have experienced invasive plant species when positioning translocation projects. Planting Cycas seedlings in biodiverse native forest but away from a conspecific individual may lead to the greatest success in population recovery. Full article

Livestock production, as one of the oldest and most significant human activities, plays a vital role in fulfilling the global demand for human nutrition and other animal-related products while contributing to poverty reduction. However, it is also important to address the environmental impact of livestock animals. Over 60% of the global biomass harvested annually to support human activity is directed towards this sector, raising concerns about its sustainability. In addition to substantial water and fertilizer usage reported in recent years, it is estimated that 14.5% of global greenhouse gas emissions are generated by the livestock sector. Furthermore, the increasing amount of manure resulting from intensive animal farming raises concerns about its disposal and potential water pollution. The degradation of pasture and rangeland is another significant contributor to soil erosion. Multiple approaches are being studied to reduce the environmental impact of livestock production, but a sustainable alternative may be through forestry. Forests play a vital role in countering livestock emissions by absorbing billions of tons of carbon dioxide each year, and they act as a crucial carbon sink. Furthermore, the diversity and age of forests impact the carbon sequestration process. Forests also help to combat climate change by reducing soil erosion and regulating the water cycle. As such, sustainable forest management is essential as forests provide multiple benefits, including economic, environmental, and social benefits, while also sequestering carbon. In this review, the current impact of modern livestock production is described, along with the potential for mitigating it through forestry-based solutions. Full article

Artificial light at night (ALAN) demonstrated a new ecological factor that influences organisms through a multi-approach. Yet, the impacts of ALAN on understory plants remain largely unknown. We evaluated whether ALAN would affect the leaf mass per area (LMA) of understory plants through a two-year field light experiment in a tropical rubber plantation in south China. We hypothesized that ALAN could impact the understory in two ways: by directly supplementing light to aboveground plant parts (which increases LMA) and indirectly affecting soil nutrient composition by attracting insects (which decreases LMA). We selected two species: Colocasia gigantea, representing shade-tolerant species, and Melastoma candidum, representing light-demanding species. We measured canopy openness, LMA, soil nutrients, and individual distance away from light resources. Our Bayesian linear mixed model showed a negative relationship between LMA and the strength of ALAN, indicating that ALAN may influence LMA more indirectly by enhancing soil nutrient availability rather than directly acting as a light resource. This relationship was significant for Colocasia gigantea but not for Melastoma candidum. These results suggest that ALAN might have complex and species-specific impacts on the understory ecosystem. Our study underscores the need for continued research and informed management of anthropogenic ecosystems. Full article

Forest phytophysiognomies have specific spatial patterns that can be mapped or translated into spectral patterns of vegetation. Regions of spectral similarity can be classified by reference to color, tonality or intensity of brightness, reflectance, texture, size, shape, neighborhood influence, etc. We evaluated the power of accuracy of supervised classification algorithms via per-pixel (maximum likelihood) and geographic object-based image analysis (GEOBIA) for distinguishing spectral patterns of the vegetation in the northern Brazilian Amazon. A total of 280 training samples (70%) and 120 validation samples (30%) of each of the 11 vegetation cover and land-use classes (N = 4400) were classified based on differences in their visible (RGB), near-infrared (NIR), and medium infrared (SWIR 1 or MIR) Landsat 8 (OLI) bands. Classification by pixels achieved a greater accuracy (Kappa = 0.75%) than GEOBIA (Kappa = 0.72%). GEOBIA, however, offers a greater plasticity and the possibility of calibrating the spectral rules associated with vegetation indices and spatial parameters. We conclude that both methods enabled precision spectral separations (0.45–1.65 μm), contributing to the distinctions between forest phytophysiognomies and land uses—strategic factors in the planning and management of natural resources in protected areas in the Amazon region. Full article

Wildlife communities are positively affected by ecological restoration and reforestation. Understanding the dynamics of mammal communities along a gradient of a human-dominated habitat to a protected habitats, right up to a reforestation habitat, is crucial for assessing the effects of reforestation on conservation biology and disease ecology. We used data obtained from a set of camera traps and live traps implemented in the “Spillover Interface” project. A network analysis showed that the reforested area was central in the sharing of mammal species between human-dominated habitats, such as plantations, and the protected area. A network analysis also confirmed the centrality of the domestic dog and the rodent Rattus tanezumi (R. tanezumi) in shared habitats and the co-occurrence with other mammal species. This rodent species was previously mentioned as a bridge species between habitats favouring disease transmission. This study is a first step to identify potential reservoirs and habitat interfaces associated with the risk of zoonotic diseases and pathogen spillover. Full article

Cultivating cotton and sustaining its productivity are challenging in temperate arid regions around the globe. Exploring suitable cotton cultivation areas to improve productivity in such climatic regions is essential. Thus, this study explores the ecologically suitable areas for cotton cultivation using the MaxEnt model, having 375 distribution points of long-staple cotton and various factors, including 19 climatic factors, 2 terrain factors, and 6 soil factors in Xinjiang. The area under the curve (AUC) of the predicted results was greater than 0.9, indicating that the model’s predictions had fairly high accuracy. However, the main environmental factors that affected the cotton’s growth were the lowest temperature in the coldest month, the hottest month, the precipitation in the driest season, and the monthly average temperature difference. Further, the temperature factors contributed 71%, while the contribution ratio of terrain and soil factors was only 22%. The research indicated that the current planting area was consistent with the predicted area in many areas of the study. Still, some areas, such as the Turpan region northwest of Bayingolin Mongol Autonomous Prefecture, are supposed to be suitable for planting cotton, but it is not planted. The current potential distribution area of long-staple cotton is mainly located in Aksu Prefecture and the northern part of the Kashgar Prefecture region. The climatic prediction shows that the growing area of long-staple cotton may expand to southern Altay, central Aksu, and Bortala Mongol Autonomous Prefecture. This study will be helpful for cotton cultivation suitability areas in Xinjiang and other regions with similar environments. Full article

Accelerometers are powerful tools for behavioral ecologists studying wild animals, particularly species that are difficult to observe due to their cryptic nature or dense or difficult to access habitats. Using a supervised approach, e.g., by observing in detail with a detailed ethogram the behavior of an individual wearing an accelerometer, to train a machine learning algorithm and the accelerometer data of one individual from a wild population of Javan slow lorises (Nycticebus javanicus), we applied a Random Forest model (RFM) to classify specific behaviors and posture or movement modifiers automatically. We predicted RFM would identify simple behaviors such as resting with the greatest accuracy while more complex behaviors such as feeding and locomotion would be identified with lower accuracy. Indeed, resting behaviors were identified with a mean accuracy of 99.16% while feeding behaviors were identified with a mean accuracy of 94.88% and locomotor behaviors with 85.54%. The model identified a total of 21 distinct combinations of six behaviors and 18 postural or movement modifiers in this dataset showing that RFMs are effective as a supervised approach to classifying accelerometer data. The methods used in this study can serve as guidelines for future research for slow lorises and other ecologically similar wild mammals. These results are encouraging and have important implications for understanding wildlife responses and resistance to global climate change, anthropogenic environmental modification and destruction, and other pressures. Full article

A first assessment of genetic diversity and expansion of the invasive species Amorpha fruticosa L. was estimated in the 91E0* (Annex I Dir. 92/43/EEC) priority habitat of Nestos. A. fruticosa is a perennial deciduous shrub belonging to the family Fabaceae and is native to the south-western part of North America, which recently was introduced to Europe as an ornamental plant. Its expansion through the cross-border river of Nestos has significant negative effects on the 91E0* habitat (a habitat with Alnus glutinosa, Populus alba, and Ulmus minor). Herein, we studied the genetic diversity with amplified fragment length polymorphisms fragments of eastern and western populations in order to see if there is one genetic pool for the species. Furthermore, we estimated the regeneration index (IR) in order to see the potential expansion of this invasive species. Results showed that eastern and western populations have almost equal heterozygosity (He) and with a slightly higher value for the western population, which was in agreement with the results of the IR. This is an innovative study that discusses the implications of A. fruticosa of 91E0* habitat in Nestos and proposes management measures to eliminate its expansion and improve the resilience of the habitat. Full article

The purpose of this research is to develop a Graded Biodiversity Assessment (GBA) index to provide an estimation of the biodiversity in managed natural forests. In order to facilitate the present project, parameters are performed, confirmed, and annotated for their use as GBA components, notably the wood stock, age, canopy density, regeneration existence, and aspect of the forest under study. These five parameters are easily retrieved from the standard forest management plans. To assist the application of this forest-specific GBA index, data for each of the five index components is coded in three biodiversity levels as per the original description, with group cut-offs of 0, 0.5, and 1. We compute the Consistency Index to quantify the degree of reliability of our selection of GBA components ξ (Ksi) of the Best-Worst Method (BWM). With the proposed GBA index, foresters canhave a new tool at their disposal, which can be used to drive decision making and determineforest regions with low or high biodiversity value, with five parameters that are common in the standard forest management plans. Full article

Plant–pollinator interactions research can assist in the development of more ecologically friendly crop breeding methods, leading to enhanced global food security. In the present study, we have aimed to assess fifteen floral traits as insect attractancies of six bitter vetch (Vicia ervilia (L.) Willd.) landraces, a neglected crop. Four traits related to seed yield were also measured. Abundance and foraging behavior of potential insect pollinators on bitter vetch flowers were recorded, and their species were identified. Differences among landraces regarding floral and yield traits were statistically significant in most cases. A total number of four insect species were recorded as positively visiting flowers and constituting potential pollinators of bitter vetch. At a landrace level, there was a positive correlation between potential insect pollinators’ foraging activity and the number of open flowers, especially for the landrace ERV65-Kastania, Korinthia (p ≤ 0.01). Floral tube length, as well as standard petal length, was also positively correlated in some cases with potential insect pollinator species abundance and their visitation frequency. A positive correlation was also recorded between seed yield-related traits, which varied among landraces, and potential insect pollinators’ foraging activity. The results showed that bitter vetch flowers can attract and receive positive visits from insects, despite their mainly self-pollination reproductive system. Bitter vetch flower traits, such as the number of open flowers, floral tube length, and standard petal length, could, therefore, be useful as breeding tools, aiming to develop varieties with insect pollinator-friendly traits that could lead to enhanced seed yield production and help to conserve wild insect species biodiversity in the context of sustainable agriculture. Full article

Several insect species visit the flowers of a plant to obtain floral rewards in the form of pollen and/or nectar. In return, we would anticipate that those visitors would contribute to the reproductive success of the plant. Do these visitors contribute equally towards the reproductive success of the plant? This issue has been the interest of many pollination ecologists. To find a solution to this problem, I investigated the pollination ecology of rocket (Eruca vesicaria (L.) Cav. ssp. sativa (Mill.) Thell), an important leafy vegetable used as salad. I captured the flower visitors with a hand net from the experimental field and had these identified. I also recorded the number of loose pollen grains carried on the body of the visitors of different species and deposited on the stigmas. Effects of single and multiple visits of visitors on the seed set of rocket flowers were also determined. Abundances and foraging rates of the flower visitors of this species were recorded and their values were used to calculate their respective contributions towards the reproductive success of this species. Five species of Hymenoptera, three of Diptera, one of Lepidoptera, and one of Coleoptera visited the flowers of the rocket. Apis florea was the most abundant among the flower visitors, followed by the dipterous flies, Apis mellifera, Apis dorsata, Andrena savignyi, and Andrena leaena in descending order. The number of loose pollen grains carried and deposited, foraging behaviors, foraging rates, and abundances did not provide conclusive measures to differentiate the contributions of different flower visitors towards the reproductive success of the rocket. However, the data recorded on abundances, foraging behaviors, and foraging rates together could do so. Accordingly, Andrena savignyi was the most efficient pollinator of rocket, followed by Andrena leaena, Apis dorsata, Apis mellifera, and Apis florea; dipterous flies were the least efficient pollinators of this plant species. In rocket, 28.84% of pollination was brought by Andrena savignyi, 24.69% by Andrena leaena, 20.34% by Apis dorsata, 18.37% by Apis mellifera, and 7.7% by Apis florea; dipterous flies caused only 0.06% pollination. Butterflies were very rare and Coccinella sp. was not a pollinator of this plant. Therefore, not all the pollinators of rocket contributed equally towards its reproductive success (seed production). Bees brought about 99.94% of total pollination and melittophily distinctly predominated over other pollination modes. However, among the bees, native bees together are the major pollinators in the flowers of rockets and accomplished more than 81.5% pollination. Therefore, the conservation of native bees is most important for the pollination of crops such as rockets. Full article