Trends in fragmentation and connectivity of Paspalum quadrifarium grasslands in the Buenos Aires province, Argentina

Landscape dynamics of Paspalum quadrifarium grasslands analyzed by Morphological Spatial Pattern Analysis (MSPA)

10.7287/peerj.preprints.27281v1 ◽

2018 ◽

Author(s):

Marcelo L Gandini ◽

Bruno D Lara ◽

Laura Beatriz Moreno ◽

Maria A Cañibano ◽

Patricia A Gandini

Keyword(s):

Spatial Pattern ◽

Management Practices ◽

Pattern Analysis ◽

Central Area ◽

Wide Distribution ◽

Spatial Pattern Analysis ◽

Percentage Increase ◽

Coverage Area ◽

Binary Images ◽

Morphological Spatial Pattern Analysis

Background. Despite its wide distribution worldwide, only 4.6% of temperate grasslands are included within systems of protected areas. In Argentina, this situation is even more alarming: only 1.05% is protected. The study area (central area of the southern Salado River basin) has a large extent of grasslands of Paspalum quadrifarium (Pq) which has been target since the last century of a variety of agricultural management practices including fire burning for cattle grazing. Methods. Binary images of presence-absence data of Pq from a 42-year (1974-2016) land cover change study were used as base data. MSPA (Morphological Spatial Pattern Analysis) and Network Analysis were performed to the data using Guidos Toolbox for the estimation of habitat and connectivity dynamics of the Pq patches (fragments). Results. A loss of the coverage area and habitat nuclei of this grassland was observed between the beginning and the end of the study period. A drastic reduction in connectivity was also evident in resulting maps. The number of large Pq grassland fragments (> 50 ha) decreased during the study period, and fragmentation measured as number of components (patches) was higher at the end of study period. The Pq pajonal nuclei had their minimum representativeness in 2000, and recovered slightly in 2011, but with a significant percentage increase of the small patches (=islets) and linear elements as bridges and branches. Large corridors (mainly edge of roads) could be observed at the end of study period, while the total connectivity of the landscape pattern drops abruptly. Discussion. The habitat reduction could have an impact on the ecosystem functioning and the mobility of some species of native fauna. The connecting elements of the landscape were maintained and/or recovered in percentage in 2011 and 2016. This fact, although favoring the dispersion of the present diversity in the habitat nuclei could cause degradation by an edge effect. On the methodological side, the use of a proved tool as Guidos Toolbox for evaluating forest fragmentation could also be useful for monitoring dynamics of a grassland-habitat fragmentation.

Landscape dynamics of Paspalum quadrifarium grasslands analyzed by Morphological Spatial Pattern Analysis (MSPA)

10.7287/peerj.preprints.27281 ◽

2018 ◽

Author(s):

Marcelo L Gandini ◽

Bruno D Lara ◽

Laura Beatriz Moreno ◽

Maria A Cañibano ◽

Patricia A Gandini

Keyword(s):

Spatial Pattern ◽

Management Practices ◽

Pattern Analysis ◽

Central Area ◽

Wide Distribution ◽

Spatial Pattern Analysis ◽

Percentage Increase ◽

Coverage Area ◽

Binary Images ◽

Morphological Spatial Pattern Analysis

Background. Despite its wide distribution worldwide, only 4.6% of temperate grasslands are included within systems of protected areas. In Argentina, this situation is even more alarming: only 1.05% is protected. The study area (central area of the southern Salado River basin) has a large extent of grasslands of Paspalum quadrifarium (Pq) which has been target since the last century of a variety of agricultural management practices including fire burning for cattle grazing. Methods. Binary images of presence-absence data of Pq from a 42-year (1974-2016) land cover change study were used as base data. MSPA (Morphological Spatial Pattern Analysis) and Network Analysis were performed to the data using Guidos Toolbox for the estimation of habitat and connectivity dynamics of the Pq patches (fragments). Results. A loss of the coverage area and habitat nuclei of this grassland was observed between the beginning and the end of the study period. A drastic reduction in connectivity was also evident in resulting maps. The number of large Pq grassland fragments (> 50 ha) decreased during the study period, and fragmentation measured as number of components (patches) was higher at the end of study period. The Pq pajonal nuclei had their minimum representativeness in 2000, and recovered slightly in 2011, but with a significant percentage increase of the small patches (=islets) and linear elements as bridges and branches. Large corridors (mainly edge of roads) could be observed at the end of study period, while the total connectivity of the landscape pattern drops abruptly. Discussion. The habitat reduction could have an impact on the ecosystem functioning and the mobility of some species of native fauna. The connecting elements of the landscape were maintained and/or recovered in percentage in 2011 and 2016. This fact, although favoring the dispersion of the present diversity in the habitat nuclei could cause degradation by an edge effect. On the methodological side, the use of a proved tool as Guidos Toolbox for evaluating forest fragmentation could also be useful for monitoring dynamics of a grassland-habitat fragmentation.

Farmers’ knowledge and perception of finger millet blast disease and its control practices in western Kenya

CABI Agriculture and Bioscience ◽

10.1186/s43170-021-00033-y ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Wilton Mbinda ◽

Agnes Kavoo ◽

Fredah Maina ◽

Margaret Odeph ◽

Cecilia Mweu ◽

...

Keyword(s):

Finger Millet ◽

Management Practices ◽

Smallholder Farmers ◽

Descriptive Analysis ◽

Wide Distribution ◽

Blast Disease ◽

Eastern Africa ◽

Planting Density ◽

Global Food Security ◽

Disease Occurrence

Abstract Background Finger millet blast disease, caused by Pyricularia oryzae, is a serious constrain of finger millet production which is threatening global food security especially to the resource poor smallholder farmers in arid and semi-arid regions. The disease adversely affects finger millet production and consumption due to its wide distribution and destruction in all finger millet growing areas of southern Asia and eastern Africa. Here, we present a study that investigated the occurrence, impact, risk factors and farmers’ knowledge and perceptions of finger millet blast in Kenya. Methods We surveyed blast disease occurrence and interviewed farmers in Bungoma and Kisii Counties of Kenya during March–April 2019. Data were analysed using SPSS statistical program. Descriptive analysis was done by calculating means, percentages, frequencies, and standard errors. Comparative statistics, chi-square and t-tests, were used to evaluate differences existing among the farm characteristics and socio-demographics and the knowledge and perceptions of blast disease and its management practices. Results Our results show that blast disease is prevalent in all surveyed areas and adversely affects the productivity of the crop leading to poor yields. The disease occurrence varied from 92 to 98%, and was significantly higher in the major finger millet growing areas compared to the minor ones. Blast occurrence was associated with rainfall, altitude, planting density, intercropping and other farming practices. In all the surveyed regions, farmers had little knowledge about blast disease identification, its detection and spread. Further, the farmers’ awareness of blast disease control was inconsistent with established practices. Conclusions Our results show mitigation of finger millet blast disease should aim at improving farmers’ adoption of best practices through development of acceptable blast-resistant finger millet varieties, use of sustainable disease management practices, fostering linkages and creating new partnerships in the production-supply chain and maintaining a functional seed system. Findings from this study provide essential insights for effective decision making and management of the disease. This is fundamental to sustainable and secure food and income for finger millet growing farmers in Kenya.

A Multi-Pollutant Air Quality Health Index (AQHI) Based on Short-Term Respiratory Effects in Stockholm, Sweden

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16010105 ◽

2019 ◽

Vol 16 (1) ◽

pp. 105 ◽

Cited By ~ 8

Author(s):

Henrik Olstrup ◽

Christer Johansson ◽

Bertil Forsberg ◽

Andreas Tornevi ◽

Agneta Ekebom ◽

...

Keyword(s):

Air Quality ◽

Birch Pollen ◽

Mean Value ◽

Emergency Department Visits ◽

Percentage Increase ◽

Health Index ◽

Mean Values ◽

Quality Health ◽

The Mean ◽

Air Quality Health Index

In this study, an Air Quality Health Index (AQHI) for Stockholm is introduced as a tool to capture the combined effects associated with multi-pollutant exposure. Public information regarding the expected health risks associated with current or forecasted concentrations of pollutants and pollen can be very useful for sensitive persons when planning their outdoor activities. For interventions, it can also be important to know the contribution from pollen and the specific air pollutants, judged to cause the risk. The AQHI is based on an epidemiological analysis of asthma emergency department visits (AEDV) and urban background concentrations of NOx, O3, PM10 and birch pollen in Stockholm during 2001–2005. This analysis showed per 10 µg·m–3 increase in the mean of same day and yesterday an increase in AEDV of 0.5% (95% CI: −1.2–2.2), 0.3% (95% CI: −1.4–2.0) and 2.5% (95% CI: 0.3–4.8) for NOx, O3 and PM10, respectively. For birch pollen, the AEDV increased with 0.26% (95% CI: 0.18–0.34) for 10 pollen grains·m–3. In comparison with the coefficients in a meta-analysis, the mean values of the coefficients obtained in Stockholm are smaller. The mean value of the risk increase associated with PM10 is somewhat smaller than the mean value of the meta-coefficient, while for O3, it is less than one fifth of the meta-coefficient. We have not found any meta-coefficient using NOx as an indicator of AEDV, but compared to the mean value associated with NO2, our value of NOx is less than half as large. The AQHI is expressed as the predicted percentage increase in AEDV without any threshold level. When comparing the relative contribution of each pollutant to the total AQHI, based on monthly averages concentrations during the period 2015–2017, there is a tangible pattern. The AQHI increase associated with NOx exhibits a relatively even distribution throughout the year, but with a clear decrease during the summer months due to less traffic. O3 contributes to an increase in AQHI during the spring. For PM10, there is a significant increase during early spring associated with increased suspension of road dust. For birch pollen, there is a remarkable peak during the late spring and early summer during the flowering period. Based on monthly averages, the total AQHI during 2015–2017 varies between 4 and 9%, but with a peak value of almost 16% during the birch pollen season in the spring 2016. Based on daily mean values, the most important risk contribution during the study period is from PM10 with 3.1%, followed by O3 with 2.0%.

Squamata, Scincidae, Mabuya dorsivittata (Cope, 1862): distribution extension in Buenos Aires province, Argentina

Check List ◽

10.15560/7.3.388 ◽

2011 ◽

Vol 7 (3) ◽

pp. 388 ◽

Cited By ~ 3

Author(s):

Jorge Williams ◽

Federico Kacoliris

Keyword(s):

South America ◽

Buenos Aires ◽

New Records ◽

Wide Distribution ◽

Buenos Aires Province ◽

Previous Record ◽

Northern Sector

Mabuya dorsivttata is a lizard with a wide distribution in South America. In Buenos Aires province, Argentina, previous voucher records exist only from its northern sector and from Mar del Plata city. In this work, two new records of M. dorsivittata from Buenos Aires province are presented: (1) Azul city (36°46’50” S, 50°51’10” W) and (2) Mar del Tuyú city (37°20’08” S, 59°07’60” W). These new records are located about 175 km from the nearest previous record.

Lobizon and Navira, two new genera of wolf spiders from Argentina (Araneae: Lycosidae)

Zootaxa ◽

10.11646/zootaxa.2195.1.1 ◽

2009 ◽

Vol 2195 (1) ◽

pp. 1-33 ◽

Cited By ~ 6

Author(s):

LUIS N. PIACENTINI ◽

CRISTIAN J. GRISMADO

Keyword(s):

Type Species ◽

Buenos Aires ◽

Wide Distribution ◽

Buenos Aires Province ◽

New Genera ◽

Wolf Spiders ◽

Northwestern Argentina ◽

San Luis ◽

The Family ◽

Two New Species

Two new genera in the family Lycosidae Sundevall, 1833 from Argentina are proposed. Lobizon gen. nov. comprises five species: Lobizon corondaensis (Mello-Leitão, 1941) comb. nov. (type species), L. minor (Mello Leitão, 1941) comb. nov., and L. humilis (Mello-Leitão, 1944) comb. nov., all these with a wide distribution in Argentina, and two new species: L. ojangureni sp. nov. from the montane forests of Northwestern Argentina, and L. otamendi sp. nov. from the northeastern Buenos Aires Province. The monotypic Navira gen. nov. is erected for N. naguan sp. nov. from Córdoba and San Luis Provinces. Trochosippa anomala (Mello-Leitão, 1945) and Alopecosa unguiculata Mello-Leitão, 1944 are considered junior synonyms of L. corondaensis and L. humilis respectively. A putative synapomorphy uniting the two genera is the massive, greatly elongated terminal apophysis which is grooved along its length. The subfamily placement of the two new genera is briefly discussed, and it is concluded that they probably belong to the Artoriinae Framenau, 2007 or Venoniinae Lehtinen & Hippa, 1979.

Bus networks as graphs: new connectivity indicators with operational characteristics

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2014-0054 ◽

2014 ◽

Vol 41 (9) ◽

pp. 788-799 ◽

Cited By ~ 5

Author(s):

Liliana Quintero-Cano ◽

Mohamed Wahba ◽

Tarek Sayed

Keyword(s):

Public Transportation ◽

Network Connectivity ◽

Traffic Analysis ◽

Coverage Area ◽

Transit Network ◽

Network Characteristics ◽

Operational Characteristics ◽

Public Transportation System ◽

Bus Networks ◽

Transit Agencies

A transit network, visualized as a graph, can be evaluated using indicators such as connectivity, coverage, directness, and complexity, among others, based on the relationships between network elements. This study focuses on the analysis of interconnected and operationally complicated bus networks, a shortcoming of existing approaches tailored to simpler, metro networks. A new procedure is proposed for drawing bus networks as graphs, by disaggregating them into sub-networks at the traffic analysis zone level. As well, improved network connectivity indicators are proposed which incorporate the influence of bus operational characteristics. The effect of bus route transfers is analyzed by introducing intermediate walking transfer edges. The contribution of this research will provide transit agencies with quantitative measures to analyze the network characteristics and the related operational attributes at a zonal sub-network level across the agency’s coverage area. The proposed methodology was demonstrated by applying it to the Greater Vancouver Regional District public transportation system.

Genome-wide co-expression distributions as a metric to prioritize genes of functional importance

10.1101/2020.01.17.910216 ◽

2020 ◽

Author(s):

Pâmela A. Alexandre ◽

Nicholas J. Hudson ◽

Sigrid A. Lehnert ◽

Marina R.S. Fortes ◽

Marina Naval-Sánchez ◽

...

Keyword(s):

Network Connectivity ◽

Wide Distribution ◽

Small Subset ◽

Data Sets ◽

Biological Signal ◽

Genome Wide ◽

Gene Level ◽

Complementary Strategy ◽

Enrichment Process ◽

Genome Wide Gene Expression

AbstractGenome-wide gene expression is routinely used as a tool to gain a systems-level understanding of complex, biological processes. Numerical approaches that have been used to highlight influential genes include abundance, differential expression, differential variation, network connectivity and differential connectivity. Network connectivity tends to be built on a small subset of extremely high co-expression signals that are deemed significant, but this overlooks the vast majority of pairwise signals. Here, we aimed to assess a complementary strategy, namely whether the entire shape of the distribution of genome-wide co-expression values contains a meaningful biological signal that has hitherto remained hidden from view. We have developed a computational pipeline to assign one of 8 distributions (including normal, skewed, bimodal, kurtotic, inverted) to every gene. We then used a hypergeometric enrichment process to determine if particular genes (regulators versus non-regulators) and properties (differentially expressed or not) tend to be associated with particular distributions greater than would be expected by chance. Examination of several distinct data sets spanning 4 species indicates that there is indeed an additional biological signal present in the genome-wide distribution of co-expression values which would be overlooked by currently adopted approaches.Author summaryHigh-throughput technologies, such as RNA-Seq, enables access to a vast amount of data. Here, we describe a new approach to interrogate these data and extract further information to help researchers to understand complex phenotypes. Our method is based on gene-level co-expression distributions which were compared to eight possible template shapes to group genes with similar behaviours. The method was tested using five different datasets and the consistency of the results indicate it can be used as a complementary strategy to analyse transcriptomic data.

Fragilaria rinoi sp. nov. (Fragilariales, Fragilariophyceae) from periphytic river samples in Central Portugal

European Journal of Taxonomy ◽

10.5852/ejt.2016.248 ◽

2016 ◽

Cited By ~ 1

Author(s):

Cristina Delgado ◽

M. Helena Novais ◽

Saúl Blanco ◽

Salomé F.P. Almeida

Keyword(s):

Central Area ◽

River Basins ◽

Scanning Electron Micrographs ◽

Diatom Species ◽

Alkaline Ph ◽

Mean Values ◽

Central Portugal ◽

Lis River ◽

Scanning Electron ◽

Freshwater Diatom

A new benthic freshwater diatom, Fragilaria rinoi Almeida & C.Delgado sp. nov., is described from river periphyton samples in Portugal. Fragilaria rinoi sp. nov. is illustrated and discussed based on populations collected from the Vouga, Mondego and Lis river basins in central Portugal and compared with the type material of Fragilaria vaucheriae (Kütz.) J.B.Petersen. The morphological features of the new diatom species are documented through light and scanning electron micrographs, including a comparative analysis with related species of the genus (F. candidagilae Almeida, C.Delgado, Novais & S.Blanco, F. intermedia Grunow in Van Heurck, F. neointermedia Tuji & D.M.Williams, F. recapitellata Lange-Bert. & Metzeltin, F. perminuta (Grunow) Lange-Bert., F. vaucheriae and F. microvaucheriae C.E.Wetzel & Ector). Fragilaria rinoi sp. nov. is characterized by solitary cells without spines, lanceolate valves with slightly rostrate apices, a narrow, linear axial area, and a large, unilateral central area. Fragilaria rinoi sp. nov. may be confused with F. microvaucheriae in terms of length, striae density and outline, although a morphometric analysis revealed that F. rinoi sp. nov. is significantly wider. Fragilaria rinoi sp. nov. is present in rivers with high dissolved oxygen concentrations, medium to high conductivity, neutral to slightly alkaline pH and high mean values of nitrates and ammonium.

Spatial mapping of soil properties in Konkan region of India experiencing anthropogenic onslaught

PLoS ONE ◽

10.1371/journal.pone.0247177 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0247177

Author(s):

Ram Ratan Verma ◽

Tapendra Kumar Srivastava ◽

Pushpa Singh ◽

B. L. Manjunath ◽

Anil Kumar

Keyword(s):

Soil Properties ◽

Soil Ph ◽

Management Practices ◽

Available Phosphorus ◽

Spatial Mapping ◽

Available N ◽

Management Zones ◽

Mean Values ◽

Wide Range ◽

Fe And Mn

Soils of Indian Konkan region, part of ecologically sensitive Western Ghats have been subjected to anthropogenic activities of late. This has endangered the ecological security through conspicuous losses in topsoil quality. The rationale of the present study was to map the soil properties and create management zones for ensuring food and nutritional security. The study was conducted in South Goa district of the state of Goa located in Konkan region. A total of 258 geo-referenced soil samples were collected and analyzed for pH, EC, SOC, available N, P, K and DTPA extractable micronutrients viz., Zn, Cu, Fe and Mn. Soil pH was found to be in acidic range. A wide variability existed in SOC content ranging from 0.12–5.85%. EC was mostly neutral with mean value 0.08±0.37 dSm-1, while available nitrogen (AN), available phosphorus (AP) and available potassium (AK) varied in range from 56.4–621.6 kg ha-1, 0.5–49.7 kg ha-1 and 31.5–786.2 kg ha-1 with mean values 211.2±76.9, 8.4±8.2 and 202.3±137.6 kg ha-1, respectively. A wide range was exhibited by cationic DTPA extractable Zn, Cu, Fe and Mn with mean values, 0.22±0.30, 0.44±0.60, 7.78±5.98 and 7.86±5.86 mg kg-1, respectively. Soil pH exhibited significant positive correlation with EC, AP AK and Zn and negative correlation with Fe and Cu. SOC exhibited significantly correlated with AN, AP, AK, Zn and Fe. Geo-statistical analysis revealed J-Bessel as best fit semivariogram model for pH, AP and AK; Rational Quadratic for EC, SOC, Zn and Mn; Hole effect for AN; Stable for Cu and K-Bessel for Fe for their spatial mapping. Four principal components showed eigenvalues more than one and cumulative variability of 59.38%. Three distinct soil management zones showing significant variation in soil properties were identified and delineated for wider scale management of soils. Precision nutrient management based on spatial variation and their mapping would enable refined agricultural and environmental management practices in the region.