Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Environ Sci Pollut Res Int ; 30(29): 74031-74044, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37199838

RESUMEN

Aside from Ramsar Convention awareness programs, the concept of wetlands is mostly ignored in developing countries. Wetland ecosystems are essential to hydrological cycles, ecosystem diversity, climatic change, and economic activity. Under the Ramsar Convention, there are 2414 wetlands that are internationally recognized, and Pakistan is home to 19 of them. The major goal of this study is to use the satellite image technology to locate Pakistan's underutilized wetlands (Borith, Phander, Upper Kachura, Satpara, and Rama Lakes). The other goals are to understand how these wetlands are affected by climate change, ecosystem change, and water quality. We used analytical techniques including supervised classification and Tasseled Cap Wetness to identify the wetlands. To find changes caused by climate change, Quick Bird high-resolution images was used to create the change detection index. Tasseled Cap Greenness and the Normalized Difference Turbidity Index were also used to assess the water quality and changes in the ecology in these wetlands. Sentinel-2 was used to analyze data from 2010 and 2020. ASTER DEM was also used to do a watershed analysis. The land surface temperature (°C) of a few selected wetlands was calculated using Modis data. Rainfall (mm) data was taken from PERSIANN (precipitation estimation from remotely sensed information using artificial neural networks) databases. Results indicated that in 2010, the water content of Borith, Phander, Upper Kachura, Satpara, and Rama Lakes was 22.83%, 20.82%, 22.26%, 24.40%, and 22.91%. While in 2020, these lakes' water ratios are 21.33%, 20.65%, 21.76%, 23.85%, and 22.59%, respectively. Therefore, the competent authorities must take precautions to ensure that these wetlands are preserved in the future in order to improve the dynamics of the ecosystem.


Asunto(s)
Ecosistema , Humedales , Tecnología de Sensores Remotos , Pakistán , Monitoreo del Ambiente/métodos
2.
Insects ; 13(11)2022 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-36421961

RESUMEN

We report the nesting biology and ecology of Megachile cephalotes Smith, 1853 for the first time in Pakistan. Wooden and bamboo trap nests were deployed at three different locations in Bahawalpur district, Pakistan, from January 2020 to May 2021. A total of 242 nests of M. cephalotes were occupied in all three locations with the maximum abundance in the Cholistan Institute of Desert Studies. Megachile cephalotes remained active from March to September (the spring and summer seasons). In a nest, females made 7-8 brood cells each having a length of 1.2-2.3 cm. Plant resin was used to construct cells and mud or animal dung to plug the nest entrance. A vestibular cell was also made between the outermost brood cell and the nest entrance that ranged from 1.4 to 2.5 cm in length. No intercalary cells were observed in the nests. The males took 65.3 days to become adults, while the females took 74.78 days. The sex ratio was significantly biased toward females in all three locations. Grewia asiatica was the predominant pollen grain species found in the brood cells. Megachile cephalotes were observed collecting resin from Acacia nilotica, Prosopis juliflora, and Moringa oleifera. Three cleptoparasites of this species were also recorded: Euaspis carbonaria, Coelioxys sp., and Anthrax sp. This study set up a background to encourage new studies on artificial nesting and provides tools for proper biodiversity management and conservation.

3.
Insects ; 13(11)2022 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-36354861

RESUMEN

The research was focused on the ability of wheat aphids Sitobion avenae, harboring bacterial secondary symbionts (BSS) Hamiltonella defensa or Regiella insecticola, to withstand exposure to fungal isolates of Beauveria bassiana and Metarhizium brunneum. In comparison to aphids lacking bacterial secondary symbionts, BSS considerably increased the lifespan of wheat aphids exposed to B. bassiana strains (Bb1022, EABb04/01-Tip) and M. brunneum strains (ART 2825 and BIPESCO 5) and also reduced the aphids' mortality. The wheat aphid clones lacking bacterial secondary symbionts were shown to be particularly vulnerable to M. brunneum strain BIPESCO 5. As opposed to wheat aphids carrying bacterial symbionts, fungal pathogens infected the wheat aphids lacking H. defensa and R. insecticola more quickly. When treated with fungal pathogens, bacterial endosymbionts had a favorable effect on the fecundity of their host aphids compared to the aphids lacking these symbionts, but there was no change in fungal sporulation on the deceased aphids. By defending their insect hosts against natural enemies, BSS increase the population of their host society and may have a significant impact on the development of their hosts.

4.
PLoS One ; 16(2): e0247124, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33606792

RESUMEN

Assessment of resource partitioning in pollinators at a particular place can be used to conserve plant communities by minimizing their inter-specific competition. Current study was conducted to investigate the occurrence of this phenomenon among plant communities under sub-tropical conditions for the first time in Pakistan. We considered the entire available flowering plant and floral visitor communities in the study area-Lal Suhanra forest of Bahawalpur, Pakistan- along with different variations among them based on morphology, color and symmetry (functional groups) i.e. four functional groups among insects and nine among plants. Weekly floral visitor censuses were conducted during spring season -from the first week of March to the fourth week of May 2018. Thirty individuals of each plant species -in bloom- were observed for floral visitors in each census. Plant species with different floral shapes, colors and symmetry did not show any significant resource partitioning. The Non-metric multidimensional scaling analysis followed by one-way ANOSIM test showed non- significant differences among all the pair of floral shapes, colors (except white and yellow) and symmetry (R-value < 0.168). However, SIMPER test suggested that flies were the most common group that contributed more towards within group similarities of different floral shapes (19 to 21% similarity), colors (16 to 30%) and symmetry (19%) followed by long-tongue bees i.e. 14 to 21%, 9 to 19% and 18%, respectively. Our results suggest that plant communities under sub-tropical conditions of Pakistan exhibit a generalist pollination system with no significant resource partitioning in pollinator species. Therefore, plant communities may have high competition for pollinator species which exhibits fewer implications of species loss on overall pollination process. Our study provides the basis for understanding the partitioning of pollinator guilds under sub-tropical conditions. Future studies should focus on functional traits in more detail at the community and the population scales for their possible impact on resource partitioning.


Asunto(s)
Magnoliopsida/crecimiento & desarrollo , Polinización/fisiología , Animales , Dípteros/fisiología , Flores/anatomía & histología , Himenópteros/fisiología , Lepidópteros/fisiología , Magnoliopsida/anatomía & histología , Pakistán , Especificidad de la Especie , Clima Tropical
5.
Saudi J Biol Sci ; 27(1): 189-194, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31889835

RESUMEN

Being the ultimate beneficiary of ecosystem services provided by on-farm agricultural biodiversity, the participation of farmers in its sustainable utilization and conservation is crucial. How much aware they are with the significance and conservation of agricultural biodiversity in order to improve their crop yield remains unclear, especially from the developing courtiers. Pollination is one of such ecosystem services, enormously contributed by the wild bees. In the present study, we have investigated the knowledge of farmers about bees and pollination in general in three districts i.e. Multan, Bahawalpur and Khanewal of southern Punjab, Pakistan. Some 300 farmers (100 cucurbit growers in each district using convenient sampling method) were interviewed using a semi-structured questionnaire. Respondents were first presented with a box of insect specimens and then were asked to identify bees among those. Those who identified correctly were asked to state about their nesting sites. Only 11% of the respondents could correctly identify the bees and half of them could report something about nesting sites. A majority (63%) of the farmers was unable to tell fertilization requirements in cucurbits, 59% could not distinguish female flower from the male flower and 64% could not state any benefit of bees. However, upon briefing about the significance of bee pollinators, 58% of the farmers showed eagerness to conserve bees at their farms. Keeping in view the inadequacies of farmers' knowledge about wild bees and pollination in general, the present study also gives some policy recommendations.

6.
Saudi J Biol Sci ; 26(7): 1799-1803, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31762661

RESUMEN

The yearlong association of a native bee, Pseudapis oxybeloides (Halictidae: Hymenoptera) was studied with 72 plant species in a sub-tropical planted forest and some adjacent agricultural landscapes at Multan, Pakistan. The study resulted in 66 interactions of P. oxybeloides with only 24 plant species in 15 families while other 48 plant species were not visited by this bee. The maximum abundance of P. oxybeloides (7-9 individuals) was recorded on Achyranthes aspera and Launaea procumbens followed by Ageratum conyzoides, Trianthema portulacastrum and Cleome viscosa (5-6 individuals). Majority (19) of plant species were visited by only 1-4 individuals. The bee activity was started in the month of March which attained its peak in May followed by a gradual decline until September. No bees were observed during the months of January and February. There was a significant positive relationship between bee abundance and number of flowering plant species. Bee abundance had a strong positive relationship with temperature while it had a strong negative relationship with relative humidity (%). Floral abundance increased with the number of flowering plant species while it was not influenced by floral span of plant species. Besides giving the floral host plants of P. oxybeloides, the current study also gives a better understanding of its seasonality along with its relationships with different biotic and abiotic factors under local conditions. These findings can help in maintaining and managing P. oxybeloides population particularly and other native bees in general at local scale.

7.
Saudi J Biol Sci ; 26(7): 1835-1842, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31762665

RESUMEN

This study investigated pollinator assemblage diversity and richness in four forested ecosystems of southern Punjab, Pakistan, with different landscape types. Pirowal is situated in the plains of irrigated Punjab, Lal Suhanra is part of a sandy desert ecosystem, Ghazi Ghat is part of the Indus River delta, and Fort Munro is located in dry hilly mountains. A yearlong survey of pollinator populations was carried out in these four forested ecosystems from January to December of 2010. Fortnightly hand netting was performed for collecting flower-visiting insects whereas, pan traps of three colors (white, blue, and yellow) were deployed for collecting the data. A total of 8,812 individuals from two orders (Lepidoptera and Diptera) were observed, including 22 families and 154 species. Bees were the most abundant, with 4,502 individuals, and the most species-rich taxa, with 70 species in five families, followed by flies having 2,509 individuals and 51species in 10 families. Wasps were the least abundant with 1,801 individuals and 33 species in seven families. The assemblage structure of pollinator communities as visualized through rank abundance curves showed that there were many species with low abundance and only a few species with a much higher abundance. The most abundant species among the bees, in order, were Nomia sp.3, Megachile bicolor, and Colletes sp.3; among flies, Syrphus sp.2, Calliphoridae sp.1, and Empididae sp.4; and among wasps, Tiphiidae sp.1, Myzininae sp.2, and Scelionidae sp.1.

8.
PLoS One ; 14(9): e0222635, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31568475

RESUMEN

Aphids are major pests of wheat crop in Pakistan inflicting considerable economic losses. A better knowledge of landscape scale spatial distribution of aphids and their natural enemies could be used to improve integrated pest management programs. Therefore, the present study aimed to document spatio-temporal variations in populations of wheat aphids and their natural enemies in Pakistan. The 2-year survey study was carried out at ten experimental farms located in five districts of four contrasted agro-ecological zones of eastern Pakistan (Punjab area) i.e. District Chakwal in arid zone, Gujranwala in rice-cropped zone, Faisalabad in central mixed-cropped zone, and Khanewal and Multan in cotton-cropped zone. The dominant aphid species i.e. Schizaphis graminum, Rhopalosiphum padi, R. maidis and Sitobion avenae varied significantly among the five districts surveyed. The population of S. graminum was observed more abundant in arid, R. padi in rice, S. avenae in aird and rice, and R. maidis in cotton-I zones. Aphids ended their population dynamics on 25th March in central mixed-cropped zone and 12th April in other three zones. Various species of natural enemies, mainly Coccinella septumpunctata, C. undecimpunctata, Menochilus sexmaculata, Chrysoperla carnea, Syrphidae and parasitoid mummies were inconsistently observed in four agro-ecological zones. The population of C. septumpunctata, was observed more abundant in rice zone, C. undecimpunctata and C. carnea in cotton-I and arid zones, M. sexmaculata in cotton-I and II zones, Syrphidae in cotton-I zone and parasitoid mummies in rice and arid zones. There were no clear relationships between aphid and the natural enemy populations. The present study may serve as a baseline regarding distribution of wheat aphids and their natural enemies and the results provided insights for further studies on the potential top-down (natural enemies) versus bottom-up (fertilization and irrigation regimes) forces in management of wheat aphids in eastern Pakistan.


Asunto(s)
Áfidos/fisiología , Escarabajos/fisiología , Triticum/parasitología , Animales , Ecología , Pakistán , Dinámica Poblacional
9.
Saudi J Biol Sci ; 26(4): 860-865, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31049015

RESUMEN

Pollinators are key components of the global biodiversity, providing vital ecosystem services of pollination to crops and wild plants. Understanding pollinator assemblage and how it changes spatially is important in order to device effective ecosystem management planning. This is the first empirical study to explore pollinator community structure in four widely isolated nature reserves of southern Punjab, Pakistan, i.e., the central agricultural plain (Pirowal Forest), the Indus delta plain (Ghazi Ghat Wetland), hilly mountains (Fort Munro), and a sandy desert (Lal Suhanra Forest). Six assemblage parameters, i.e., abundance, richness, dominance, evenness, Simpson index, and Shannon-Wiener index, were studied over seven consecutive months (February to August 2012). Maximum abundance and richness of the pollinators were recorded at Ghazi Ghat (1354 individuals and 84 species), followed by Pirowal (1331 individuals and 80 species), Lal Suhanra (1197 individuals and 77 species), and Fort Munro (808 individuals and 65 species). The highest values of Simpson and evenness indexes were recorded at Fort Munro, while the Shannon-Wiener and dominance indexes were highest at Ghazi Ghat and Pirowal. Species richness was highest for bees, while it was lowest for flies, yet the latter were the highest in abundance among the four pollinator groups. The current study is a first account of pollinator assemblage structure in four widely isolated forest reserves of Punjab, Pakistan. This will support ecosystem management planning, and opens doors for further research in order to reveal complexities in pollinator assemblage structure especially in relation with plant communities.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...