The influence of intraspecific trait variation on species interactions makes trait-based approaches critical to understanding eco-evolutionary processes. Because species occupy habitats that are ...patchily distributed in space, species interactions are influenced not just by the degree of intraspecific trait variation but also the relative proportion of trait variation that occurs within- versus between-patches. Advancement in trait-based ecology hinges on understanding how trait variation is distributed within and between habitat patches across the landscape. We sampled larval spotted salamanders (Ambystoma maculatum) across six spatially discrete ponds to quantify within- and between-pond variation in mass, length, and various metrics associated with their relationship (scaling, body condition, shape). Across all traits, within-pond variation contributed more to total observed morphological variation than between-pond variation. Between-pond variation was not negligible, however, and explained 20-41% of total observed variation in measured traits. Between-pond variation was more pronounced in salamander tail morphology compared to head or body morphology, suggesting that pond-level factors more strongly influence tails than other body parts. We also observed differences in mass-length relationships across ponds, both in terms of scaling slopes and intercepts, though differences in the intercepts were much stronger. Preliminary evidence hinted that newly constructed ponds were a driver of the observed differences in mass-length relationships and morphometrics. General pond-level difference in salamander trait covariation suggest that allometric scaling of morphological traits is context dependent in patchy landscapes. Effects of pond age offer the hypothesis that habitat restoration through pond construction is a driver of variation in trait scaling, which managers may leverage to bolster trait diversity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Communities assemble through a combination of stochastic processes, which can make environmentally similar communities divergent (high β-diversity), and deterministic processes, which can make ...environmentally similar communities convergent (low β-diversity). Top predators can influence both stochasticity (e.g. colonization and extinction events) and determinism (e.g. size of the realized species pool), in community assembly, and thus their net effect is unknown. We investigated how predatory fish influenced the scaling of prey diversity in ponds at local and regional spatial scales. While fish reduced both local and regional richness, their effects were markedly more intense at the regional scale. Underlying this result was that the presence of fish made localities within metacommunities more similar in their community composition (lower β-diversity), suggesting that fish enhance the deterministic, relative to the stochastic, components of community assembly. Thus, the presence of predators can alter fundamental mechanisms of community assembly and the scaling of diversity within metacommunities.
A calcified nodule is a type of potentially vulnerable plaque accounting for approximately 2% to 7% of coronary events. Because its intravascular ultrasound (IVUS) features have never been validated, ...the aim of this study was to assess the IVUS characteristics of calcified nodules in comparison to histopathology. IVUS was performed in 856 pathologic slices in 29 coronary arteries (11 left anterior descending, 5 left circumflex, and 13 right coronary arteries) in 18 autopsy hearts. Pathologic sections were analyzed every 2 mm; qualitative and quantitative findings of matched IVUS were analyzed. IVUS detected calcification in 285 frames; 17 (6.0%) were calcified nodules, and 268 (94.0%) were non-nodular calcium by histopathology. Two calcified nodules (11.8%) were solitary, and 15 (88.2%) were adjacent to non-nodular calcium. IVUS characteristics of calcified nodules were (1) a convex shape of the luminal surface (94.1% in calcified nodules vs 9.7% in non-nodular calcium, p <0.001), (2) a convex shape of the luminal side of calcium (100% vs 16.0%, p <0.001), (3) an irregular luminal surface (64.7% vs 11.6%, p <0.001), and (4) an irregular leading edge of calcium (88.2% vs 19.0%, p <0.001). Luminal area at the calcified nodule site was larger (6.2 ± 2.4 vs 4.3 ± 1.6 mm2 , p <0.001) and plaque burden less (57 ± 6% vs 68 ± 5%, p <0.001) than at the minimum luminal area site. In conclusion, calcified nodules have distinct IVUS features (irregular and convex luminal surface) permitting their prospective identification in vivo.
The land use and land cover (LULC) changes and the implications of soil and irrigation water salinity have adverse effects on crop production and the ecosystems of arid and semiarid regions. In this ...study, an attempt has been made to analyze and monitor the LULC changes using multitemporal Landsat data for years 1986, 1998, 2007, and 2016 in Al-Ahsa Oasis, Saudi Arabia. In addition, efforts were made to measure the spatial distribution of soil and irrigation water salinity along the oasis. The supervised maximum likelihood classification method was applied to classify the individual images independently. Moreover, soil samples were collected at surface soil depth from the selected LULC types, namely, date palm, croplands, and bare land. Also, groundwater samples were collected from bore wells located in agricultural farms. The spatial distribution of the soil salinity (Ec
) and irrigation water salinity (EC
) was classified based on the Food and Agriculture Organization guidelines. The results showed that significant changes in LULC patterns have occurred during 1986–2016 in the study area. The EC
was found higher in date palm compared with cropland and bare land. However, the spatial distribution of the EC
over the oasis indicated that 94% of irrigation water ranged between moderate and severe salinity risk. The study concludes that salinity management practices need to be developed in the study area aiming to sustain crop yields, improve soil properties, and minimize the environmental impacts of LULC changes on the ecosystem of Al-Ahsa Oasis.
Remote sensing (RS) can efficiently support the quantification of crop water requirements and water productivity (WP) for evaluating the performance of agricultural production systems and provides ...relevant feedback for management. This research aimed to estimate winter wheat water consumption and WP in the central clay plain of Sudan by integrating remotely sensed images, climate data, and biophysical modelling. The wheat crop was cultivated under a centre-pivot irrigation system during the winter season of 2014/2015. The Landsat-8 satellite data were used to retrieve the required spectral data. The Surface Energy Balance Algorithm for Land (SEBAL) was supported with RS and climate data for estimating the Actual Evapotranspiration (ETa) and the WP for the wheat crop. The SEBAL outputs were validated using the FAO Penman–Monteith method coupled with field measurements and observation. The results showed that the seasonal ETa ranged from 400 to 600 mm. However, the WP was between 1.2 and 1.5 kg/m
during the wheat cycle. The spatial ETa and WP maps produced by the SEBAL model and Landsat-8 images can improve water use efficiency at field scale environment and estimate the water balance over large agricultural areas.
Kandó-Melocco, Ferenc. 2015. An Anti-Nazi at Hitler's Table: Political Memoirs of a Hungarian Nobleman Who Dared to Oppose Both Hitler and the Communists. (trans. and ed. Esther Kando Odescalchi). ...North Charleston, SC: CreateSpace. 162 pp., Illus.; Odescalchi, Esther Kando. 2016. My Escape: Memoirs of a Hungarian Teenage Freedom Fighter. North Charleston, SC: CreateSpace. Illus. 148 pp.
One of the most profound recent global changes has been the proliferation of urban metropolitan areas. A consequence of urbanization is a reduction in abundance, or diversity, of wildlife. One ...exception, is the proliferation of vectors of disease; recent years have seen the emergence and resurgence of diseases vectored by species closely associated with humans.
, a mosquito with a near global range and broad ecological niche, has been described as an urban, suburban, or rural vector, or a forest edge species depending on local conditions. We tested the hypothesis that abundance and phenological patterns of this species vary among different land use types in a temperate city because of the variation in the biotic and abiotic conditions characteristic of those habitat types.
populations in urban and suburban areas were an order of magnitude larger than in rural areas and were detected several weeks earlier in the season. Additionally, we found fewer overall mosquito species, higher temperatures, lower nitrogen, higher pH, and faster water evaporation in larval habitats in urban vs. rural areas. By understanding the ecological differences that facilitate a species in one habitat and not another, we can potentially exploit those differences for targeted control.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The personal experiences of individuals who lived through the catastrophes of World War II, the Holocaust and the 1956 Hungarian Revolution have been told in many recent memoirs, greatly expanding ...our understanding of these historical events. In addition to the experiences of the narrators, the fate of their family members, friends, colleagues and entire communities who were all impacted by these events are also illuminated in these accounts. The two memoirs by George Pogany (b. 1928) cover his life since the early 1930s in Hungary, the Holocaust, communism, his escape to the West in 1956, his settlement in England, resettlement in Holland and his years as an international management consultant in several countries. Few memoirs transmit so vigorously the sweep, resiliency, and duration of the author's life and reflections as in Pogany's exceptionally detailed and insightful twofold memoir.
Habitat isolation is well known to alter patterns of species' abundance, richness, and the ratios of predators: prey. Less clear, however, is how isolation alters interactions within food webs. Here, ...we present the results from an experiment performed in artificial ponds (mesocosms) manipulating habitat isolation crossed with a predator reduction treatment to disentangle how isolation mediates the top-down effect of predators. The strength of the trophic cascade, from predators, through herbivores, to producers, was considerably stronger in connected than in isolated habitats. We further found that the overall richness of both predator and herbivore species declined strongly with isolation. Experimental predator reductions suggest that the mechanism underlying the herbivore response was likely mediated by a keystone predator effect; when predators were reduced, herbivore richness was lower, and there was no discernable effect of isolation on herbivore richness. Finally, we found that the composition of predators in more isolated habitats consisted of species that were smaller and likely less effective predators than species that persisted in less isolated habitats. In all, our experiment showed that habitat isolation can alter the structure of communities by a combination of direct effects of the species in question, as well as effects mediated through their interactions in the food web.
The effects of disturbance on local species diversity have been well documented, but less recognized is the possibility that disturbances can alter diversity at regional spatial scales. Since ...regional diversity can dictate which species are available for recolonization of degraded sites, the loss of diversity at regional scales may impede the recovery of biodiversity following a disturbance. To examine this we used a chemical disturbance of rotenone, a piscicide commonly used for fish removal in aquatic habitats, on small fishless freshwater ponds. We focused on the non-target effects of rotenone on aquatic invertebrates with the goal of assessing biodiversity loss and recovery at both local (within-pond) and regional (across ponds) spatial scales. We found that rotenone caused significant, large, but short-term losses of species at both local and regional spatial scales. Using a null model of random extinction, we determined that species were selectively removed from communities relative to what would be expected if species loss occurred randomly. Despite this selective loss of biodiversity, species diversity at both local and regional spatial scales recovered to reference levels one year after the addition of rotenone. The rapid recovery of local and regional diversity in this study was surprising considering the large loss of regional species diversity, however many aquatic invertebrates disperse readily or have resting stages that may persist through disturbances. We emphasize the importance of considering spatial scale when quantifying the impacts of a disturbance on an ecosystem, as well as considering how regional species loss can influence recovery from disturbance.
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