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Migratory species can experience limiting factors at different locations and during different periods of their annual cycle. In migratory birds, these factors may even occur in different hemispheres. Therefore, identifying the distribution of populations throughout their annual cycle (i.e., migratory connectivity) can reveal the complex ecological and evolutionary relationships that link species and ecosystems across the globe and illuminate where and how limiting factors influence population trends. A growing body of literature continues to identify species that exhibit weak connectivity wherein individuals from distinct breeding areas co-occur during the nonbreeding period. A detailed account of a broadly distributed species exhibiting strong migratory connectivity in which nonbreeding isolation of populations is associated with differential population trends remains undescribed. Here, we present a range-wide assessment of the nonbreeding distribution and migratory connectivity of two broadly dispersed Nearctic-Neotropical migratory songbirds. We used geolocators to track the movements of 70 Vermivora warblers from sites spanning their breeding distribution in eastern North America and identified links between breeding populations and nonbreeding areas. Unlike blue-winged warblers (Vermivora cyanoptera), breeding populations of golden-winged warblers (Vermivora chrysoptera) exhibited strong migratory connectivity, which was associated with historical trends in breeding populations: stable for populations that winter in Central America and declining for those that winter in northern South America.

Microbial stoichiometry has become a key aspect in ecological research as shifts in microbial C:N, C:P and N:P ratios upon nutrient addition are presumed to give insight into relative nutrient limitations for soil microorganisms–with far-reaching implications for biogeochemical processes. However, this expectation has never been tested against direct methods of microbial growth responses to nutrient addition. We therefore manipulated a subtropical grassland and forest soil with multifactorial C-, N- and P-additions during 30 days to induce changes in limiting resources and evaluated the resulting soil microbial growth rates, microbial biomass stoichiometry, potential enzyme activities and microbial community composition. Our results show that microbial stoichiometric shifts upon nutrient addition ambiguously predict growth-limiting nutrients for soil microbes. For example, P- and NP-addition to the grassland soil significantly shifted the microbial N:P ratio, which suggests increased N- relative to P-limitation. Microbial growth responses however indicated that soil microbes remained C limited. The same applies for the forest soil, where P-, CN-, NP- and CNP-additions shifted the microbial N:P ratio, yet microbial growth remained C limited. This indicates that microorganisms can immobilize N and P for storage when C is the main limiting nutrient, and that intracellular storage of N and P is responsible for the observed shifts in microbial stoichiometry. Moreover, our data imply that shifts in microbial C:N ratios do not necessarily indicate shifts in microbial community composition and suggest that soil microorganisms–when subject to resource pulses–are stoichiometrically quite plastic.

Aim: To inform conservation planning in the face of climate change, our objectives were to map spatial patterns of tree and songbird macrorefugia; to identify climatic limiting factors by region and taxonomic group; and to quantify multi-scale topographic components of end-of-century biotic refugia. Location: United States and Canada outside the far north. Time period: End of the 21st century. Major taxa studied: Trees and songbirds. Methods: We used species distribution models for 324 trees and 268 songbirds to develop a macrorefugia index using species-specific climate velocity. Maps of multispecies refugia potential were developed for each taxonomic/functional group and quantile regression was used to identify climatic limiting factors and relationships with multi-scale topographic variables. Results: End-of-century macrorefugia for both trees and songbirds were concentrated in western mountains and, to a lesser extent, in north-eastern coastal regions. For the highest-value refugia, precipitation was generally most limiting in the north, and warm temperatures and moisture availability were limiting in the south. Tree refugia were more limited by precipitation and moisture, while songbird refugia were more limited by temperature. Upper-percentile refugia, but not median values, were well explained by topographic conditions. Songbird refugia were strongly associated with elevation, while coastal proximity and landform composition (particularly headwaters) were important for both groups. There was a general lack of concordance between patterns of current species richness and future climate refugia. Main conclusions: Macrorefugia patterns are partly explained by steep elevational or latitudinal temperature gradients and/or moderate climates, such as coastal regions. However, climatic limiting factors for these refugia suggest contrasts in the ecological processes governing warm-end range limits for different taxa in different regions. Our framework can be applied to other regions, taxa, and time periods to generate and explain biologically meaningful indices of macrorefugia for conservation planning.

Watershed characterization is essential for sustainable watershed management and effective resource utilization, particularly in assessing changes resulting from interventions. This study investigates the biophysical and socio-economic conditions of the Agewmariam watershed, aiming to develop land capability and suitability maps while identifying viable management options. Biophysical data, including land slope, soil properties, erosion severity, stoniness/rockiness cover, and vegetation cover, were collected through field surveys and analyzed using overlay analysis in ArcGIS. Socio-economic data, encompassing population demographics, income, and expenditure, were gathered via individual interviews, complete census, and focus group discussions and summarized using descriptive statistics. The study identified 259 households with an average family size of 4 and a demographic dependency ratio of 96.6%. The major sources of income are crop production and livestock rearing supplemented by casual labor and food aid. The average farmland holding size is 0.5 ha, with sorghum, barley, teff, and wheat as the dominant crops. The watershed is characterized by six land capability classes (classes II, III, IV, VI, VII, and VIII). The suitability analysis indicated that the watershed is not currently suitable for wheat and teff crops unless physical, chemical, and biological management improvements are implemented. The study revealed that the major limiting factors for land capability and suitability were slope, erosion severity, stoniness, soil organic matter, and soil texture. The socio-economic characterization enhanced awareness about the local socio-economic condition, informing appropriate planning and management strategies. The study recommends intensive soil and water conservation intervention, afforestation on hillsides, changing the land use system, and the addition of organic matter and fertilizers to enhance land capability and suitability for sustainable agricultural practices.

Water and energy are recognized as the most influential climatic vegetation growth-limiting factors. These factors are usually measured from ground meteorological stations. However, since both vary in space, time, and scale, they can be assessed by satellite-derived biophysical indicators. Energy, represented by land surface temperature (LST), is assumed to resemble air temperature; and water availability, related to precipitation, is represented by the normalized difference vegetation index (NDVI). It is hypothesized that positive correlations between LST and NDVI indicate energy-limited conditions, while negative correlations indicate water-limited conditions. The current project aimed to quantify the spatial and seasonal (spring and summer) distributions of LST–NDVI relations over Europe, using long-term (2000–2017) MODIS images. Overlaying the LST–NDVI relations on the European biome map revealed that relations between LST and NDVI were highly diverse among the various biomes and throughout the entire study period (March–August). During the spring season (March–May), 80% of the European domain, across all biomes, showed the dominance of significant positive relations. However, during the summer season (June–August), most of the biomes—except the northern ones—turned to negative correlation. This study demonstrates that the drought/vegetation/stress spectral indices, based on the prevalent hypothesis of an inverse LST–NDVI correlation, are spatially and temporally dependent. These negative correlations are not valid in regions where energy is the limiting factor (e.g., in the drier regions in the southern and eastern extents of the domain) or during specific periods of the year (e.g., the spring season). Consequently, it is essential to re-examine this assumption and restrict applications of such an approach only to areas and periods in which negative correlations are observed. Predicted climate change will lead to an increase in temperature in the coming decades (i.e., increased LST), as well as a complex pattern of precipitation changes (i.e., changes of NDVI). Thus shifts in plant species locations are expected to cause a redistribution of biomes.

The deep application of green and healthy education is becoming increasingly important in the intelligent teaching of English in higher education institutions. This paper constructs a green and healthy education system based on the theory of educational ecology, transforms the limiting factors in English teaching into non-limiting factors through positive feedback conditions, and reasonably who sets learning tasks according to the tolerance and optimum degree of the educational ecosystem. After that, the permeability of the green education concept was analyzed by combining the green health education system with teaching intelligent English drawing in higher education institutions. The average degree of English teachers' understanding of the connotation of green education in higher education institutions is only 0.74, while the average students' subjectivity evaluation is 0.65, and only 25.3% of English classrooms have students' subjectivity evaluation of 0.85 and above, and most of the classrooms still cannot get rid of teachers' subjectivity. The concept of green and healthy education can effectively optimize classroom teaching structure, improve teaching effectiveness and promote students' personalized development.

In mobile animals, movement behavior can maximize fitness by optimizing access to critical resources and minimizing risk of predation. We sought to evaluate several hypotheses regarding the effects of landscape structure on American marten foraging path selection in a landscape experiencing forest perforation by patchcut logging. We hypothesized that in the uncut pre-treatment landscape marten would choose foraging paths to maximize access to cover types that support the highest density of prey. In contrast, in the post-treatment landscapes we hypothesized marten would choose paths primarily to avoid crossing openings, and that this would limit their ability to optimally select paths to maximize foraging success. Our limiting factor analysis shows that different resistant models may be supported under changing landscape conditions due to threshold effects, even when a species’ response to landscape variables is constant. Our results support previous work showing forest harvest strongly affects marten movement behavior. The most important result of our study, however, is that the influence of these features changes dramatically depending on the degree to which timber harvest limits available movement paths. Marten choose foraging paths in uncut landscapes to maximize time spent in cover types providing the highest density of prey species. In contrast, following landscape perforation by patchcuts, marten strongly select paths to avoid crossing unforested areas. This strong response to patch cutting reduces their ability to optimize foraging paths to vegetation type. Marten likely avoid non-forested areas in fragmented landscapes to reduce risk of predation and to benefit thermoregulation in winter, but in doing so they may suffer a secondary cost of decreased foraging efficiency.

Forest ecosystems play an essential role in climate stabilization, and the study of their capabilities in this aspect is of paramount importance. How climate changes affect the biomass of trees and stands in transcontinental gradients is unknown today? The objective of this study was (a) to verify the operation of the law of the limiting factor at the transcontinental level when modeling changes in the biomass of trees and stands of the genus spp. of Eurasia in relation to geographically determined indicators of temperatures and precipitation, and (b) to show the possibility of using the constructed climate-conditioned models of tree and stand biomass in predicting temporal changes in tree and stand biomass based on the principle of space-for-time substitution. As a result of the implementation of the principles of the limiting factor and space-for-time substitution, a common pattern has been established on tree and stand levels: in sufficiently moisture-rich climatic zones, an increase in temperature by 1 °C with a constant amount of precipitation causes an increase in aboveground biomass, and in moisture-deficient zones, it decreases; in warm climatic zones, a decrease in precipitation by 100 mm at a constant average January temperature causes a decrease in aboveground biomass, and in cold climatic zones, it increases.

Sugarcane is one of the important plantation commodities that is widely cultivated in Indonesia as a raw material for the sugar industry. One type of land that is commonly used for sugarcane cultivation is sandy soil, however, this soil has shortcomings due to nutrients availability which affects the productivity of sugarcane. This study aims to determine the limiting factor of sugarcane productivity in sandy soil through the Leaf Sampling Unit (LSU) analysis. Foliar nutrient levels of Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), and Magnesium (Mg) were determined. The parameters of plant growth observed included stalk height, stalk diameter, number of internodes per stalk, number of green leaves, number of stalk per clump, stalk fresh weight, and sugarcane productivity. Data were analyzed using correlation and descriptive tests. LSU analysis indicated that the levels of N and Ca were under sufficient conditions, at 1.98% and 0.33%, respectively. Meanwhile, the P, K, and Mg were in critical condition, with values of 0.03%, 0.09%, and 0.12%, respectively. Sugarcane stem diameter had a correlation with sugarcane productivity (r=0.985). Increasing the dose of fertilizers, especially P, K, and Mg is needed to overcome these nutrient deficiency conditions; thus the productivity of sugarcane can be optimized and sustainable.

The growth rate of eucalyptus in the dry season was significantly lower than that in the wet season. However, the limiting factors of eucalyptus growth in the dry season are not clear. In this paper, through the continuous monitoring of the diameter growth and environmental factors of 5.5-year-old Eucalyptus urophylla S. T. Blake × E. grandis W. Hill ex Maiden in the dry season, the diameter growth characteristics of eucalyptus during the dry season were studied and the limiting factors of eucalyptus growth in the dry season were determined. The water and fertilizer management activities in the dry season were evaluated to verify the growth and water use characteristics of Eucalyptus urophylla × E. grandis in the dry season under the conditions of mitigation limiting factors and provide the basis for further increasing the growth rate of eucalyptus. The results show that the diameter fluctuation of Eucalyptus urophylla × E. grandis is cyclical and the diameter cumulative growth during the dry season monitoring is consistent with the Gompertz model. Atmospheric temperature and soil water content are the main factors limiting the growth of Eucalyptus urophylla × E. grandis in the dry season. Irrigation and fertilization in the dry season can significantly increase the growth of diameter at breast height (DBH) and biomass growth and significantly improve the water use efficiency in the dry season.