Spatio-temporal Evaluation of Multi-scale Cultivated Land System Resilience in Black Soil Region from 2000 to 2019:A Case Study of Liaoning Province,Northeast China

It is of great significance to systematically analyze the cultivated land system resilience(CLSR) for the black soil protection and national food security.The CLSR is impacted by planting structure adjustment and cultivated land quality decline,posing major hidden dangers to food security.It is urgent to evaluate the CLSR at multiple spatio-temporal scales.This study took Liaoning Province in the black soil region of Northeast China as an example.Based on the resilience theory,this study constructed the CLSR evaluation system from the input-feedback perspective at the provincial-scale and the city-scale,and used the rank-sum ratio comprehensive evaluation method(RSR) to analyze the key influencing factors of CLSR in Liaoning Province and its 14 cities from 2000 to 2019.The results showed that:1) the time series changes of CLSR at the provincial-scale and the city-scale in Liaoning Province were similar,both showing an increasing trend.2) The CLSR in Liaoning Province presented a spatial pattern of ‘high in the west and low in the east’ at the city-scale.3) There were seven and six main influencing factors of CLSR at the provincial-scale and the city-scale,respectively.In addition to the net income per capita of rural households,other influencing factors of CLSR were different at the provincial-scale and the city-scale.The feedback factors were dominant at the provincial-scale,and the input factors and feedback factors were dominant at the city-scale.The results could provide a reference for the utilization of black soil and draw on the experience of regional agricultural planning and adjustment.

High Prevalence of Eimeria Infection in Domestic Pigeons(Columba Livia Domestica) in Guangdong Province, Southern China

[Objective] This study aimed to make a survey of domestic pigeons for infection with Eimeria species of coccidia was conducted in Guangdong Province, southern China. [Method] A total of 244 fecal samples(102 from Huizhou, 83 from Jiangmen, 35 from Chaozhou and 24 from Guangzhou, respectively) in four pigeon breeding farms between June 2012 and March2013 were collected and examined microscopically. [Results] Eimeria oocysts were seen in 223(91.4%) fecal samples, with three species, namely E. labbeana, E.columbae and E. kapotei. E. labbeana was the most common species in Guangdong provinces with an overall prevalence of 91.4%, while a slightly lower incidence of E. columbae and E. kapotei species was detected with11.1% and 6.6%, representatively. The prevalence in different months varied ranging from 83.3% to 91.7%, with the highest prevalence in summer. Nestling groups showed obviously high infection than adult pigeons. [Conclusion] The present survey indicated the wide and severe prevalence of Eimeria infection in Guangdong domestic pigeons, which suggested that integrated measures should be taken to control and prevent coccidiosis of pigeons in this province.

Planting Performance of Pennisetum purpureum Schumab cv.Purple in the Southern Region of China

[Objective] The present experiment was conducted to investigate the yield,adaptability and quality characteristics of Pennisetum purpureum Schumach cv. Purple to provide reference for the certification and development of new varieties.[Method] With P. purpureum Schumab cv. Purple as experimental material, the variety comparison tests were conducted in Nanning, Lingyun, and Tiandeng in Guangxi from 2007 to 2009, and variety regional trials were conducted in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Its comprehensive characters of plant height, hay yield, stem-leaf ratio and nutritional components were determined, and were compared with those of P. purpureum × P.americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin. [Result] The average height of P. purpureum Schumach cv. Purple was 706.54 cm, which was5.92% and 8.44% lower than that of P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin, respectively. The average hay yield of P. purpureum Schumach cv. Purple was 32.74 t/ha in Nanning, Lingyun, and Tiandeng of Guangxi from 2007 to 2009, and 22.41 t/ha in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Although its hay yield was lower than two control varieties, the difference was not significant（P 0.05）.The stem-leaf ratio of P. purpureum Schumach cv. Purple was 0.98：1. Moreover,the analysis on the nutritional components of dry matter showed that compared with P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv.Guiminvin, the crude fiber of P. purpureum Schumab cv. Purple was decreased by4.76% and 2.78%, respectively; the neutral detergent fiber decreased by 5.07% and2.22%, respectively; the acid detergent fiber was decreased by 2.54% and 1.99%,respectively; the crude fat was increased by 64.29% and 43.75%, respectively; the calcium content was increased by 28.00% and 33.33%, respectively; the phosphorus content was increased by 9.68% and 22.73%, respectively; the total content of amino acid was increased by 43.23% and 68.41%, respectively; the anthocyanin content of leaf was increased by 400.00% and 216.90%, respectively（P 0.05）.[Conclusion] P. purpureum Schumach cv. Purple is a new high-quality forage variety with wide adaptability, high yield, rich nutrient and good palatability, which is appropriate for comprehensive exploitation and application in the southern region of China.

A comparison of the management models of protected areas between China and the southern Africa region

A comparison of the management models of protected areas between China and the African south region allows reading and evaluating the similarities and differences in the use of management model as a management tool for protected areas and specifi- cally some positive and negative features of the management approaches in these two regions. Previous to this study it verified the designation of protected areas as increasing at a faster rate than ever before, comparatively much faster now in China than southern Africa regions. With the aim of evaluating similarities and differences in the use of management model as a management tool for pro- tected areas in China and southern Africa Region, both qualitative and quantitative data were collected. Qualitative data were mainly from policy documents, scientific articles and magazine reports, whereas quantitative （secondary data） statistical data from Interna- tional Union for Conservation of Nature Resources （IUCN） and World Database on Protected Areas （WDPA）. In view of the data sources above, the study found that in China all the protected areas are state owned whilst in southern Africa regions there are some protected areas that are privately owned; also that the models or typology of governance applied are successful for the fact that they both combine co-management or collaborative management, community-conserved areas and private protected areas that are subject to greater success and can help design planning and management than those who use exclusively government management. To this, the study concluded that the use of management model is influenced by the type of governance a country applies to its reserved areas.

U-Pb Zircon Age, Geochemical and Sr-Nd Isotopic Constraints on the Age and Origin of the Granodiorites in Guilong, Southeastern Yunnan Province, Southern China

Post-collision felsic rocks in Southeastern Yunnan province contain granodiorites. U-Pb zircon ages, geochemical data and Sr-Nd isotopic data for these rocks are reported in the present paper. Laser ablation inductively coupled plasma mass spectrometry U-Pb zircon analyses yielded consistent age 252.5 ± 1.0 Ma for one sample of the felsic rocks. The granodiorites were characterized by variational and high (87Sr/86Sr)i, ranging from 0.7223 to 0.7236 and very low εNd (t) values from –29.1 to –30.4. In addition, these rocks are characterized by slight Eu negative anomalies, Nb, Ta, Ti and Sr negative anomalies on primitive mantle normalization spider. Geochemical and isotopic characteristics suggest that these rocks were derived from an enriched crust source. The granodiorites resulted from the fractionation of potassium feldspar, plagioclase and ilmenite or rutile. However, the granodiorites were unaffected by visible crustal contamination during ascent. As a result, the granodiorites may have been formed due to partial melting of crust-derived sedimentary rocks beneath southeastern Yunnan province, southern China.

Characteristics of Volcanic Rocks in the Shoshonite Province, Eastern China, and Their Metallogenesis

The shoshonite province in eastern China is characterized by extensive distribution (ca. 80000 km2) of Late Jurassic-Early Cretaceous (165-100 Ma) shoshonite series with subordinate high-K calc-alkali series. It was formed in a dominantly tensile stress field. In comparison with their analogues in island arcs and active continental margins in other countries, the volcanic rocks in the shoshonite province have their specific characteristics in petrology, mineralogy and geochemistry as well as related mineralization association, which are the comprehensive reflection of the special composition and structure of the mantle and crust of the province and the special Mesozoic regional tectonic setting.

The Evolution of Regional Economic Resilience in the Old Industrial Bases in China: A Case Study of Liaoning Province, China

The economic transformation of the old industrial bases is a key research topic among geographers in China.In this paper,we propose that the concept of regional economic resilience(RER)has unique theoretical value in analyzing the economic transformation of the old industrial bases.We constructed an analytical framework and an index system and applied the conceptual tools to study the evolution of RER in the old industrial base of Liaoning Province in China,which is currently subjected to not only sudden shocks but‘slow burn’—longer term processes of change that may nevertheless affect the regional economy.There are four main findings:first,the evolution of RER in Liaoning can be divided into four stages from 2000 to 2015.Liaoning is currently in its conservation-release period,and the next stage will be a release-reorganization period.Second,the RER of the majority of the studied cities is lower than the average value for Liaoning,and this is mainly attributed to the relatively weak vulnerability-resistance and adaptability-transformation capacity of these cities.Third,the RER levels of the 14 cities in Liaoning differ significantly.At the first level is Shenyang and Dalian,at the second level is Dandong and Yingkou,and the third level comprises the remaining cities.Fourth,regional economic resilience is mainly determined by vulnerability-resistance,which indirectly reflects Liaoning’s lack of adaptability-transformation capacity,and the ability of the region to renew or create a new development path is weak.

Review and Prospects on Rice Breeding and Extension in China

A large number of new varieties, especially hybrid rice, have been developed and released in China since 1998. The yield potential and grain quality of hybrid rice have also been improved significantly both for three-line and two-line hybrid rice including indica and japonica types as well. The trends on extension of rice varieties in China since 1986 has been marked by the increasing number of new varieties, decreasing annual planting area per variety, decreasing number of varieties with a large-scale extension area, while both the renewal rate and the proportion of core varieties with cross-provincial extension have remained unchanged. This current major problems and future goals of rice breeding and extension in China were also discussed.

Ecological Network Analysis Quantifying the Sustainability of Regional Economies: A Case Study of Guangdong Province in China

To meet the challenge of sustainable development, sustainability must be made. Ecological network analysis(ENA) was introduced in this paper as an approach to quantitatively measure the growth, development, and sustainability of an economic system. The Guangdong economic networks from 1987 to 2010 were analyzed by applying the ENA approach. Firstly, a currency flow network among economic sectors was constructed to represent the Guangdong economic system by adapting the input-output(I-O) table data. Then, the network indicators from the ENA framework involving the total system throughput(TST), average mutual information(AMI), ascendency(A), redundancy(R) and development capacity(C) were calculated. Lastly, the network indicators were analyzed to acquire the overall features of Guangdong's economic operations during 1987–2010. The results are as follows: the trends of the network indicators show that the size of the Guangdong economic network grows exponentially at a high rate during 1987–2010, whereas its efficiency does not present a clear trend over its whole period. The growth is the main characteristic of the Guangdong economy during 1987–2010, with no clear evidence regarding its development. The quantitative results of the network also confirmed that the growth contributed to a great majority of the Guangdong economy during 1987–2010, whereas the development's contribution was tiny during the same period. The average value of the sustainability indicator(α) of the Guangdong economic network was 0.222 during 1987–2010, which is less than the theoretically optimal value of 0.37 for a sustainable human-influenced system. The results suggest that the Guangdong economic system needs a further autocatalysis to improve its efficiency to support the system maintaining a sustainable evolvement.

Systematic Analysis and Optimization of the Agricultural Structure in Ethnic Regions in Northwest Sichuan Province

Based on introducing the basic conditions of the ethnic regions in northwest Sichuan Province,the thesis analyzes its agricultural development status,which can be classified into two aspects--rich natural resources and slow agricultural economic growth.Through the analysis on the agricultural structure of northwest Sichuan Province,it is found that the production efficiency and economic benefits of crop planting in this region are low,animal husbandry,as a major industry in pastoral region,sees high production efficiency,the agricultural production is still at the resource-oriented stage;its agricultural structure is still the farming-pastoral structure relying mainly on animal husbandry,planting is dominated by crop planting and potato planting,animal husbandry mainly produces dairy and beef;the ethnic regions in northwest Sichuan Province is endowed with the advantages to grow crops,beans and fruits as well as to produce beef,mutton and milk,among which,three industries,say fruit,beef and dairy are with increasing location quotient and gradually strengthening industrial comparative advantage,while the location quotient of the other industries is declining and their industrial comparative advantages are more stable.In order to promote the agriculture in northwest Sichuan Province to develop in breadth and depth,the thesis proposes the following measures and suggestions:the first one is to adhere to the development strategy of modern animal husbandry;the second is to appropriately improve the proportion of economic crops;the third is to accelerate the development of green food processing industry.

Mild hypothermia for treatment of diffuse axonal injury: a quantitative analysis of diffusion tensor imaging

Fractional anisotropy values in diffusion tensor imaging can quantitatively reflect the consistency of nerve fibers after brain damage, where higher values generally indicate less damage to nerve fibers. Therefore, we hypothesized that diffusion tensor imaging could be used to evaluate the effect of mild hypothermia on diffuse axona[ injury. A total of 102 patients with diffuse axonal injury were randomly divided into two groups： normothermic and mild hypothermic treatment groups. Patient＇s modified Rankin scale scores 2 months after mild hypothermia were significant- ly lower than those for the normothermia group. The difference in average fractional anisotropy value for each region of interest before and after mild hypothermia was 1.32-1.36 times higher than the value in the normothermia group. Quantitative assessment of diffusion tensor imaging indicates that mild hypothermia therapy may be beneficial for patients with diffuse axonal injury.

Does Industry-University-Research Cooperation Matter? An Analysis of Its Coupling Effect on Regional Innovation and Economic Development

The dislocation between regional innovation and economic development directly influences the economic effect of regional innovation. However, no in-depth researches have been made on how to solve this problem. Using data from Henan Province, China,employing geographical detector technology, this paper focuses on testing whether the industry-university-research cooperation can contribute to coordinating the relation between regional innovation and economic development. It is shown that: 1) the industry-universityresearch cooperation in Henan Province is increasing gradually, and the network presents a core-edge structure, and the coupling degree between regional innovation and economic development is spatially unbalanced, which is similar to the spatial distribution of the intensity of industry-university-research cooperation;2) as an important approach to effectively connect scientific researches with market demands, the industry-university-research cooperation can help form an interactive, interconnected, coupled and coordinated virtuous relation between regional innovation and economic development. Compared with the cooperation between organizations of the same type and the separate innovation of organizations, the improvement of the industry-university-research cooperation level can better coordinate the relation between regional innovation and economic development;3) the cooperative innovation model between enterprises and universities can better promote the coupling between regional innovation and economic development, compared with many industryuniversity-research cooperation models. For underdeveloped areas lacking local knowledge base, industry-university-research cooperation should be considered as a long-term development strategy, especially using the knowledge sources of external universities and scientific research institutions to enhance innovation capability and achieve economic growth.

Climatic Characteristics of Hail Disaster and Division of Defense Region in Guizhou Province

[Objective] The aim was to study the climatic characteristics of hail disaster from 1984 to 2006 in Guizhou Province,China.[Method] Through statistical analysis,the climatic characteristics and disaster characteristics of hail from 1984 to 2006 in Guizhou Province were annalyzed and compared with previous results,then the classification standards of hail disaster were established,finally the defense zoning map of hail disaster in Guizhou Province was made.[Result] According to the statistical analysis on the historical data of hail disaster from 1984 to 2006,the frequency hail was 1 243 times in Guizhou in 23 years,that is,annual average frequency reached 54 times;annual average hailing days were 0.1-2.7 d in Guizhou Province,and the average frequency of hail was 3.8 times during each hail process;the frequency of hail was below 30 times in 52% of years and 30-80 times in 35% of years among 23 years.Hail could appear in the whole year,and 74% of hails occurred in spring,while winter had the fewest times.The results above were basically consistent with those of previous studies.Hail disaster mainly resulted in casualties and direct economic loss,and was divided into four grades according to direct economic loss,namely Grade I(extremely severe hail disaster),Grade II(severe hail disaster),Grade III(comparatively severe hail disaster) and Grade IV(medium hail disaster).The defense zoning map of hail disaster in Guizhou Province was made based on the frequency of hail and severe hail disaster,that is,the defense region at Grade I mainly distributed in Liupanshui City(in western Guizhou) and southern Guizhou;the defense region at Grade II was in the west,south and northeast of Guizhou Province,while the rest was at Grade III.[Conclusion] The study was of reference value for the defense of hail disaster in Guizhou Province.

Diagnostic Analysis on a Regional Rainstorm Weather in North-central Henan Province

[Objective] The research aimed to analyze a regional rainstorm weather process in north-central Henan Province. [Method] Based on the conventional meteorological observation data and the rainfall data of Henan Meteorological Station, the diagnostic analysis of atmospheric thermodynamics and dynamics on a rainstorm weather process in north-central Henan Province on July 19, 2010 was carried out. The characteristics of physical quantity field and the evolution of weather situation in north-central Henan Province when the rainstorm happened were studied. [Result] Western Pacific subtropical high strengthened to extend westward. The dynamic uplifting of low vortex at the middle and low layers, the strong water vapor transportation of southwest low-level jet caused the regional rainstorm weather process in north-central Henan Province. The diagnostic results of physical quantity showed that the deep, thick wet layer and the sustained water vapor convergence provided the abundant water vapor for rainstorm generation. The positive vorticity advection center developed and spread from northwest to southeast, which was favorable for the development of vertical movement. The structure maintenance of positive vorticity at the middle and low layers, negative vorticity at the middle and high levels provided the power condition for the regional rainstorm generation. The pumping effect of convergence at the middle and low layers, divergence at the high layer was favorable for the strengthening of vertical ascending motion at the low layer. The uplifting effect of dew point front at the middle and low layers triggered the release of unstable energy. The confrontation of warm and cold air was one of the important reasons for the regional rainstorm. TBB characteristic analysis showed that TBB was from -60 to -50 ℃ in north-central Henan Province in the whole strong precipitation time, and the moving speed was equivalent to that of southwest vortex. The low-value belt of TBB corresponded with the rainstorm occurrence zone in Henan, and the minimum-value center of TBB was basically consistent with the strongest center of precipitation. [Conclusion] The research provided the scientific basis for the short-term forecast of rainstorm.

Characteristics of Regional Differentiation of Urbanization Development in Anhui Province

On the basis of connotation of urbanization,by using SPSS factor analysis and cluster analysis,we establish index system of urbanization development level and conduct quantitative analysis on development level of urbanization in 17 prefecture-level city of Anhui Province,in order to find out the differentiation pattern of regional space of urbanization development in Anhui Province based on these.The results show that Anhui's difference of urbanization gradient is prominent.Classification of three clusters shows that the pattern of status quo of urbanization development in Anhui Province is "dual-nucleus" and "two-stretches";classification of five clusters show that the pattern of status quo of urbanization development in Anhui Province is "one-core","one-strip" and "three-region".From five aspects,namely natural geography,transportation location,resources distribution,economic development and administrative system,we analyze the reason and influencing factors of differentiation of urbanization development in the region.The results of three clusters and five clusters show that there is great possibility that "dual-nucleus" changes into "individual-nucleus";"one-core" and "one-strip" may evolve into "one-group".We should foster the urban agglomeration in central Anhui;perfect structure system in the perspective of integration and fostering;strengthen infrastructure construction and regional coordination system;elevate comprehensive competitiveness and guide holistic development of regional economy;promote industrialization process and promote development level of urbanization.

Research on Functional Characteristics of Karst Eco-economic Compound System in Guizhou Province

Based on the eco-economy theory,this paper analyzed the characteristics of the components of eco-economic compound system of karst region in Guizhou Province.The functional characteristics of eco-economic compound system of karst region in Guizhou Province were analyzed.The functional characteristics were as follows:low biological production of Guizhou Province;weak capacity of ecosystem;slow speed of storage and accumulation of material and serious environmental pollution;low production and efficiency of energy;serious wastes of energy.On the basis of functional characteristics of eco-economic compound System in Karst region.Some views in terms of maintenance and reconstruction of compound system,were put forward,including laying stress on improving ecological system;choosing and cultivating the advanced species that suit the Karst region;improving the amount and speed of material accumulation,at the same time,introducing into advanced production technologies and management experience;reducing the energy efficiency of each section in economic system and improving the transformation efficiency of energy.

Influencing Factors on Farming System Development in Shandong Province

The developmental situation of the farming system in Shandong Province is introduced.At present,Shandong Province is at the semi-intensive,semi-commercial and semi-sufficiency level of farming system.Eastern coast and central Shandong agricultural zones are moving in the direction of modern farming system,having formed a preliminary new pattern of the coordinated development of grain,feedstuff,economic and other crops.Influencing factors on the development of farming system in Shandong Province is analyzed,which are agricultural production condition and input level,population and food,policy measures,development of natural resources and regions,agricultural industrialization and urbanization level,and scientific and technological level.Total population will be within 100 million at the year 2020;per capita annual share of grain will be 475 kilograms;and there is great pressure on grain production.Therefore,we must change the pattern of agricultural development and accelerate the establishment of modern farming system.Agricultural machinery,water conservancy projects,and chemical fertilizer application have greatly affected the development of farming system.Improvement of production conditions has promoted the adjustment of agricultural structure,increased the planting ratio of winter wheat-summer maize,and improved multiple-cropping index.Development of agricultural industrialization has promoted the transfer of rural labor force and the establishment of modern farming system;while the unbalanced development of cities has restricted the establishment of modern farming system.Therefore,the appropriate policy,scientific and rational regional distribution,and advanced science and technology can help to set up the modern farming system in Shandong Province.

Discrepant chemical differentiation and magmatic-hydrothermal evolution of high-silica magmatism associated with Pb–Zn and W mineralization in the Lhasa terrane

High-silica(SiO_(2)>70 wt.%)granites(HSGs)are the main source of W,Sn,and rare metals.However,abundant HSGs,temporally,spatially,and genetically associated with Pb-Zn mineralization,in the Lhasa terrane(LT),provided an ideal opportunity to study the key factors responsible for Pb-Zn enrichment,instead of W-Sn enrichment.Here we contribute to this topic through U-Pb dating of zircon and garnet,and whole-rock and Sr-Nd-Hf isotopic geochemistry of ore-related quartz porphyries in the Bangbule deposit and compared these results with published data from large and giant Pb-Zn and W deposits in the LT.The magmatism-alteration-mineralization event in the Bangbule deposit was recorded by robust zircon U-Pb ages of 77.3±0.9 Ma and hydrothermal garnet U-Pb ages of 75.7±4.8 Ma,which is 10-15 Ma earlier than the main Paleocene metallogenic event and the first record of late Cretaceous Pb-Zn polymetallic mineralization in the LT.The late Cretaceous-Paleocene magmatism and mineralization events are a response to the subduction of Neotethyan oceanic lithosphere,which occurred as a result of the collision of the Indian and Asian plates.These HSGs related to Pb-Zn mineralization,with high totalalkalis and low magnesian contents,are enriched in Ba,Th,and Rb,but depleted in Ti,Eu,Sr,and P.They belong to either the S-type,or I-type granites.The Sr-Nd-Hf isotopic compositions of the Pb-Zn mineralized granites demonstrate that they were generated by the partial melting of Proterozoic basement with or without mantle-derived melt input.This was consistent with the postulated source of W enrichment in the LT.The Pb-Zn and W related granites have similar zircon-Ti-saturation temperatures,comparable low whole-rock Fe_(2)O_(3)/FeO ratios,and zircon oxygen fugacity.This indicated that the Pb-Zn-W enrichment in the high-silica magma system could be attributed to a relatively reduced magma.The Pb-Zn related HSGs,abundant quartz and feldspar phenocrysts,and weak fractionation of twin-elements in wholerock analysis,can be used to reconstruct a model of the magma reservoir.We postulate that these features could be reproduced by silica-rich crystal accumulation in a magma reservoir,with a loss of magmatic fluids.The magma associated with W mineralization exhibited a higher level of differentiation compared to the Pb-Zn related magma;however,different groups of zircon texture with varying rare earth elements and concomitance of rare earth elements tetrad effect and high fractionation of twin-elements in wholerock are formed by a magmatic-hydrothermal transition in highly evolved system.As the source and oxygen fugacities of the Pb-Zn and W related magmas are similar,the absence of a giant W-Sn deposit in the LT may indicate that parent magmas with a low degree of evolution and magmatic-hydrothermal transition are not conducive to their formation.This implies that the rocks that originated as highly evolved silicaterich parent magmas,with a high degree of magmatic-hydrothermal alteration,would need to be targeted for W-Sn mineral exploration in the LT.In summary,our results emphasize that variations in chemical differentiation and the evolution of high-silica magmatic-hydrothermal systems can lead to differences in Pb-Zn and W enrichment.This has implications for the evaluation of the mineral potential of high-silica granites and hence their attractiveness as targets for mineral exploration.

The Influence of Climate Variability on Holoplanktonic Polychaetes Populations of Ocean Sector of the Colombian Pacific Basin

Studies of holoplanktonic polychaetes in the Tropical Eastern Pacific have focused on their systematics and distribution however, population responses related to climate variability are non-existent. Therefore, the present work described for the first time the influence of the climatic variability 2004-2012 on the holoplanktonic polychaetes populations, as well as their relationship to environmental variables. Species of the Alciopidae, Lopadorrhynchidae and Iospilidae families were identified from 85 samples collected in the Pacific Basin of Colombia, contrasting them with the presence of ENSO, and correlating them with the environmental variables of temperature, salinity and chlorophyll-α concentration. Of the 14 species identified, only Lopadorrhynchus cf. henseni and L. cf. brevis increased their densities under El Niño and correlated positively with temperature. Rhynchonereella cf. petersii correlated negatively with temperature;while R. cf. gracilis and Pelagobia cf. longicirrata were positively correlated with chlorophyll-α concentration and salinity, respectively. Additionally, with the first description of the environmental ranges of the 14 species identified for the Colombian Pacific basin, it was found that the most commons species presented broader environmental ranges. The results from the current research are consistent with previous studies in other regions of the Pacific and latitudes. The responses of the organisms suggest trophic and mobility trends that were not known for tropical holoplanktonic polychaete species.