The relative importance of facilitation and competition between pairwise plants across abiotic stress gradients as predicted by the stress-gradient hypothesis has been confirmed in arid and temperate ecosystems, but the hypothesis has rarely been tested in tropical systems, particularly across nutrient gradients. The current research examines the interactions between a pioneer shrub Rhodomyrtus...

We compared the distribution of sympatric Ixodes scapularis Say and Amblyomma americanum (L.) within several suitable forested habitats at different spatial scales and characterized differences in microhabitat features accounting for the observed distribution of questing ticks. We used automatic data loggers placed in the shrub and litter layers to contrast mesoclimate and microclimate conditio...

We report on the habitat associations of 21 species of grassland birds overwintering in or migrating through southern Texas, during 1991-1992 and 1992-1993. Ninety percent of our grassland bird observations were made during winter and spring, and only 10% occurred during fall. Grassland species made up a high proportion of the total bird densities in grassland and shrub-grassland habitats, but ...

Restoration treatments are based on the largely untested notion that desired recovery of plant communities following disturbance wouldn’t occur in the absence of active intervention. We identified rate of short-term (10 year) floristic changes following removal of plant functional groups in Wyoming big sagebrush plant communities in 1999e2005 and 2008. Treatments imposed on 6 6 m plots were: 1)...

This study aimed to evaluate the effect of shrub encroachment on soil organic carbon (SOC) content at broad scales and its controls. We conducted a meta-analysis using paired control data of shrub-encroached grassland (SEG) vs. non-SEG collected from 142 studies worldwide. SOC contents (0-50 cm) were altered by shrub encroachment, with changes ranging from -50% to + 300%, with an effect size of...

[1] A greater abundance of shrubs in semiarid grasslands affects the spatial patterns of soil temperature, moisture, and litter, resulting in fertile islands with potentially enhanced soil metabolic activity. The goal of this study was to quantify the microsite specificity of soil respiration in a semiarid riparian ecosystem experiencing shrub encroachment. We quantified the response of soil re...

Spatial distribution of palatable and unpalatable plants can influence the foraging behaviour of herbivores, thereby changing plant-damage probabilities. Moreover, the immediate proximity to certain plants can benefit other plants that grow below them, where toxicity or spines act as a physical barrier or concealment against herbivores. This paper presents the results of a multi-scale experimen...

In desertified regions, shrub-dominated patches are important microhabitats for ground arthropod assemblages. As shrub age increases, soil, vegetation and microbiological properties can change remarkably and spontaneously across seasons. However, relatively few studies have analyzed how ground arthropods respond to the microhabitats created by shrubs of different plantation ages across seasons....

the composition of essential oil of leaves of the male and female shrubs of juniperus chinensis l. (growing in isfahan) was analyzed by gas choromatography(gc) and gc-mass spectrometery (ms). the main constituents of leaf oil of the male shrub were: bornyl acetate (26.1%), sabinene (18.3%), trans-sabinyl acetate (11.1%), myrcene (9.2%), limonene (6.1%), elemol (5.5%), α-cadinol (2.3%), δ-cadine...

Recent regional climate-change models indicated significant changes in the temporal and spatial distribution of rainfall in the Mediterranean-Basin region. Understanding the consequences of rainfall alterations for soil respiration and carbon processing in these regions is essential, considering their crucial functions for soil fertility and ecosystem functioning. Our aim was to evaluate the ef...