scholarly journals Smaller and Isolated Grassland Fragments Are Exposed to Stronger Seed and Insect Predation in Habitat Edges

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 54
Author(s):  
Kitti Kuli-Révész ◽  
Dávid Korányi ◽  
Tamás Lakatos ◽  
Ágota Réka Szabó ◽  
Péter Batáry ◽  
...  

Habitat fragmentation threatens terrestrial arthropod biodiversity, and thereby also leads to alterations of ecosystem functioning and stability. Predation on insects and seeds by arthropods are two very important ecological functions because of their community-structuring effects. We addressed the effect of fragment connectivity, fragment size, and edge effect on insect and seed predation of arthropods. We studied 60 natural fragments of two grassland ecosystems in the same region (Hungarian Great Plain), 30 forest-steppes, and 30 burial mounds (kurgans). The size of fragments were in the range of 0.16–6.88 ha for forest-steppe and 0.01–0.44 ha for kurgan. We used 2400 sentinel arthropod preys (dummy caterpillars) and 4800 seeds in trays for the measurements. Attack marks on dummy caterpillars were used for predator identification and calculation of insect predation rates. In the case of seeds, predation rates were calculated as the number of missing or damaged seeds per total number of exposed seeds. Increasing connectivity played a role only in generally small kurgans, with a negative effect on insect and seed predation rates in the edges. In contrast, fragment size moderated edge effects on insect and seed predation rates in generally large forest-steppes. The difference between edges and centres was more pronounced in small than in large fragments. Our study emphasizes the important role of landscape and fragment-scale factors interacting with edge effect in shaping ecosystem functions in natural grassland fragments of modified landscapes. Managing functional landscapes to optimize the assessment of ecosystem functions and services needs a multispatial scale approach.

2015 ◽  
Vol 75 (2) ◽  
pp. 347-351 ◽  
Author(s):  
G. Penido ◽  
V. Ribeiro ◽  
DS. Fortunato

This paper evaluates the post-dispersal artificial seed predation rates in two areas of the southeastern Amazon forest-savanna boundary, central Brazil. We conducted the survey in a disturbance regime controlled research site to verify if exists an edge effect in these rates and if the disturbance (in this case annual fire and no fire) affects seed predation. We placed 800 peanuts seeds in each area at regular distance intervals from the fragment`s edge. Data were analyzed by a likelihood ratio model selection in generalized linear models (GLM). The complete model (with effects from edge distance and site and its interaction) was significative (F3=4.43; p=0.005). Seeds had a larger predation rates in fragment’s interior in both areas, but in the controlled area (no disturbance) this effect was less linear. This suggests an edge effect for post-dispersal seed predation, and that disturbances might alter these effects. Even if we exclude the site effect (grouping both areas together) there is still a strong edge effect on seed predation rates (F3=32.679; p>0.001). We did not verify predator’s species in this study; however, the presence of several species of ants was extremely common in the seeds. The detection of an edge effect in only a short survey time suggests that there is heterogeneity in predation rates and that this variation might affect plant recruitment in fragmented areas of the Amazon forest. Henceforth, this seed predation should be taken in consideration in reforestation projects, where the main source of plants species is from seed distribution.


PEDIATRICS ◽  
1984 ◽  
Vol 73 (6) ◽  
pp. 799-805 ◽  
Author(s):  
Robert E. Black ◽  
Kenneth H. Brown ◽  
Stan Becker

Village-based surveillance data from longitudinal studies in rural Bangladesh have been used to evaluate the nutritional consequences of infectious diseases, including diarrhea due to specific pathogens. The prevalences of specific illnesses were related to the ponderal and linear growth of young children for 2-month and 1-year periods. Of the common illnesses, only diarrhea had a significant inverse relationship with increments of weight during 2-month periods and of length during 1 year. Diarrhea accounted for 20% of the difference in linear growth between the study children and the international reference population during the first 5 years of life. Diarrhea associated with enterotoxigenic Escherichia coli had a significant negative effect on the bimonthly weight gain of children in this community and shigellosis had the strongest negative effect on bimonthly and annual linear growth. Control of diarrhea due to enterotoxigenic E coli and Shigella would not only substantially diminish diarrheal morbidity but would also improve the growth of children and thereby reduce the prevalence of protein-energy malnutrition.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Nicholas Chesnaye ◽  
Yvette Meuleman ◽  
Esther De Rooij ◽  
Friedo W Dekker ◽  
Marie Evans ◽  
...  

Abstract Background and Aims Differences between the sexes are apparent in the epidemiology of CKD. Cross-sectional studies show that women consistently report a poorer health-related quality of life (QoL) than men, however, longitudinal studies are lacking. Here we investigate the sex-specific evolution of QoL over time in advanced CKD. As a secondary aim, we explore the sex-specific determinants of QoL. Method EQUAL is an observational prospective cohort study in stages 4 and 5 CKD patients ≥65 years not on dialysis with an incident estimated glomerular filtration rate (eGFR) < 20 ml/min/1.73m². Data on QoL (measured using the RAND-36), clinical and demographic patient characteristics were collected between April 2012 and September 2020. QoL trajectories were modelled by sex using linear mixed models, and joint models were applied to deal with informative censoring. We followed patients until death or dialysis initiation. Results We included 5151 QoL measurements in 1416 patients over a total of 1986 person years of follow-up. Overall, the physical component summary (PCS) declined with 2.0 (95% CI 1.4-2.6) points and the mental component summary (MCS) by 2.4 (95% CI 1.8-3.0) points per year. Although women had overall lower QoL scores, figure 1 demonstrates that PCS and MCS declined more than twice as fast in men (PCS: 2.4 per year, 95% CI 1.7 – 3.1, MCS: 2.9 per year, 95% CI 2.2 – 3.6) compared with women (PCS: 1.1 per year, 95% CI -0.2 – 2.0, MCS: 1.5 per year, 95% CI 0.5 – 2.4). We identified a non-linear interaction effect between sex and eGFR levels on QoL, demonstrating a stronger negative effect of decreased eGFR on both PCS (p=0.02) and MCS (p=0.04) in men compared with women. Subsequent adjustment for renal decline attenuated the difference in rate of QoL decline between men and women (difference after adjustment; PCS: 1.1, 95% CI -0.1 – 2.2, MCS: 1.2, 95% 0.0 – 2.3). In univariable analyses, higher serum haemoglobin was more beneficial to QoL in men compared to women (p-value for interaction; PCS: p=0.03, MCS: p=0.01). Higher serum phosphate had a strong harmful effect on both PCS and MCS in men, but not in women (PCS & MCS: p<0.001). The presence of pre-existing diabetes had a negative effect on PCS and MCS in men, but to a lesser extent in women (PCS: p=0.02, MCS: p=0.01). Conclusion Despite the higher overall QoL reported by men, both their physical and mental QoL declined approximately twice as fast compared with women. The faster decline in men was mediated in part by their lower levels of renal function, which had a stronger impact on their QoL as compared with women. Furthermore, in exploratory analyses we identified that high levels of phosphate, low levels of haemoglobin, and pre-existing diabetes were more detrimental to QoL in men than in women.


2021 ◽  
Vol 11 (2) ◽  
pp. 67-80
Author(s):  
Nguyen Quoc Anh ◽  
Duong Nguyen Thanh Phuong

This study investigates the impact of credit risk on the financial stability of Vietnamese commercial banks. The paper uses the Z-score to proxy the financial stability of banks. We use the data of 27 Vietnamese commercial banks on BankScope, during 2010 - 2019. The paper applied a dynamic panel data approach; the selected method is the difference GMM (DGMM). The key question discussed is which factor impacts on Z-score. Analysis results show the negative effect of non-performing loans on the financial stability of banks. When commercial banks have higher non-performing loans, the lower the financial stability is. Additionally, bank-specific variables such as equity on asset ratio, the return on equity, the size of the bank and set of macroeconomic variables affect the bank’s financial stability. Based on the analysis results, we imply relevant policies for the State Bank of Vietnam and commercial banks.


2020 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Nanda Alfarina ◽  
Hasdi Aimon

This study aims to determine the effect of monetary policy measured by the central bank’s policy rate (X1) on portfolio investment (Y) in Indonesia and United States in the long run. The data used are secondary data seouced from SEKI BI, FRED The FEd, coinmarketcap.com, and investing.com, with the VECM (Vector Error Correction Mechanism) analysis methode. The study show The study shows the differences between the results that occur in Indonesia and the United States. The policy interest rate has a significant positive effect on portfolio investment in the long run in Indonesia, while in the United States the interest rate in the long run has a significant negative effect on portfolio investment. The difference in research results between the two countries shows the need for different treatment for monetary authorities in encouraging portfolio investment 


2018 ◽  
Vol 8 (2) ◽  
pp. 131
Author(s):  
Yulia Frischanita

The purpose of this research are to analyst the negative effect of institutional ownership, audit committee and gender to audit report lag of mining company in Indonesia, Malaysia and Singapore for 2012-2016. Gender is proxied by gender of CEO and gender of Committee Audit’s Head. Not only that, the research also analyst the difference mean value of audit report lag in Indonesia, Malaysia and Singapore. This research use random purposive sampling technique because the amount company gap after purposive sampling between three counties are high. Total of population of three countries are 67 companies and mining company which fulfill the criteria of purposive sampling is 43 companies. That are consist of 34 Indonesia’s mining companies, 3 Malaysia’s mining companies and 6 Singapore’s mining companies. The final sample is 13 companies consist of 5 Indonesia’s company, 5 Singapore’s company and 3 Malaysia’s Company. Multiple Linear Regression is used to examine the effect of independent variable to dependent variable, while One Way-Anova is used to examine the difference mean value of audit report lag. The result of this research are institutional ownership have negative effect to audit report lag, while audit committee and gender don’t have effect to audit report lag. Beside that, there is no difference mean value of audit report lag in Indonesia, Malaysia and Singapore because they have same regulation about maximal day of company to publish their financial report.


2019 ◽  
Vol 78 (310) ◽  
pp. 137
Author(s):  
Jorge Alberto López Arévalo ◽  
Óscar Rodil Marzábal

<p>Este trabajo estudia los intercambios bilaterales de China con México, Chile, Costa Rica y Perú desde la óptica del comercio intraindustrial durante 1995-2017. En particular, se analizan las diferencias en el patrón de inserción intraindustrial en un contexto marcado por la existencia (Chile, Costa Rica y Perú) o no (México) de acuerdos de libre comercio con China. El estudio se completa con un análisis econométrico (efectos fijos) de los determinantes del comercio intraindustrial. Los resultados muestran una inserción de bajo perfil intraindustrial, con la excepción de algunas partidas específicas relativas a productos eléctricos y de la industria automotriz. Por otro lado, se confirma el efecto positivo del tamaño de la economía, de la inversión extranjera directa y de la diferenciación de producto, así como negativo de la diferencia en el nivel de ingreso; mientras que existe una indefinición en el papel de los acuerdos de libre comercio con China.<br /><br /></p><p>THE TRADE INTEGRATION OF CHINA IN LATIN AMERICA</p><p> </p><p><strong>ABSTRACT</strong><br />This paper studies China’s bilateral trade with Mexico, Chile, Costa Rica and Peru from the perspective of intra-industrial trade during 1995-2017. In particular, the differences in the pattern of intra-industrial insertion are analyzed in a context characterized by the existence (Chile, Costa Rica and Peru) or not (Mexico) of free trade agreements with China. An econometric analysis (fixed effects) of the determinants of intra-industrial trade completes the study. The results show a low intra-industrial profile, except for some specific items related to electrical products and the automotive industry. The positive effect of the size of the economy, foreign direct investment and product differentiation is also confirmed, as well as the negative effect of the difference in income level. However, there is an undefined role for free trade agreements with China.</p>


2010 ◽  
Vol 62 (2) ◽  
pp. 489-493 ◽  
Author(s):  
Kornelia Kurucz ◽  
Helena Kallenberger ◽  
Csilla Szigeti ◽  
J.J. Purger

The breeding success of blackbirds was investigated in April and June 2008 and 2009 in the Botanical Garden of the University of Pecs, with a total of 50 artificial nests at each of the four sessions (with 1 quail egg and 1 plasticine egg placed in every nest). In all four study periods of the two years, 2 nests (4%) were destroyed by predators. Six nests (12%, of the nests) were not discovered in either of the cases. The survival probability of artificial nests was greater in April than in June (both years), but the difference was significant only in 2008. Nests placed into a curtain of ivy (Hedera helix) on a wall were located higher up than those in bushes, yet their predation rates were quite similar. The predation values of quail vs. plasticine eggs did not differ in 2008. In the year 2009, however, significantly more quail eggs were discovered (mostly removed), than plasticine eggs. Marks that were left on plasticine eggs originated mostly from small mammals and small-bodied birds, but the disappearance of a large number of quail and plasticine eggs was probably caused by larger birds, primarily jays.


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