Study on fish life history traits and variation in the Taiwan Strait and its adjacent waters

Large portions of the world＇s fishery resources are overexploited. Life history traits of fish species are important indicators to reveal different life history strategies and to indicate population responses to fishing pressures. For this study, empirical data on fishing grounds located in the coastal area between Fujian Coast and Taiwan Island were collected. These areas have experienced severe overfishing in the past 30 years, leading to changes in the structure and function of the fish communities. Fifty-one commercial fish species in this fishing ground were selected to study the life history traits. Using the life history traits, all the species were grouped into five different life history strategies by principle component analysis. More than 60% of the species were categorized in Group 5 that was similar to r-strategists. Twenty-five commercial species were selected for further analysis of changes in life history variables, and to discuss the population responses to exploitation. Results showed that most of the species appeared to become smaller size, shorter life, earlier maturation and faster growing under long-term exploitation. The exploitation rate of each species was also calculated to further discuss the impacts of fishing pressures to fish populations. Four species were found with the severest changes on life history traits indicating some of the species might be more susceptible to exploitation. This study on fish life history traits and their long-term variations under fishing pressures could provide important scientific implications for fishery management and conservation.

Linkages among the functional traits,insect visitation rate and seed set of Gentiana taxa on the Tibetan Plateau

Maximum plant height(H_(max)),stem tissue mass density(SD),leaf mass per area(LMA),and relative growth rate(RGR)have all been linked to flowering phenology.However,it is still unknown whether these functional traits varying with flowering phenology are related to other floral traits associated with pollinator preference and reproductive success.We investigated the relationship between vegetative and floral traits,as well as the rates of insect visitation and seed set of fiveGentiana species in eastern Tibetan meadows.Our results showed that flowering onset and flowering offset time were all found to be positively correlated with the H_(max),SD,and LMA,but negatively correlated with the RGR.Flowering onset time was positively correlated with corolla diameter and pollen grain number,whereas was negatively correlated with flower number and flower longevity.The rates of insect visitation were positively related to flowering onset time,pollen grain number,corolla diameter,and seed set,but negatively related to flower number and longevity.Early flowering species have higher RGR but lower SD,LMA andH_(max),as well as smaller flowers,fewer pollen grains,longer flower longevity,and lower insect visitation rates than late-flowering plant species.Our findings indicate that floral traits are related to vegetative traits in Gentiana species.Also these plant trait relationships were associated with pollinator preference,and plant reproductive success of eastern Tibetan meadows.We speculate that these traits relationships are likely adaptive in unpredictable and often pollinator-limited environments in the Tibet alpine meadows.

Perenniality:From model plants to applications in agriculture

To compensate for their sessile nature,plants have evolved sophisticated mechanisms enabling them to adapt to ever-changing environments.One such prominent feature is the evolution of diverse life history strategies,particularly such that annuals reproduce once followed by seasonal death,while perennials live longer by cycling growth seasonally.This intrinsic phenology is primarily genetic and can be altered by environmental factors.Although evolutionary transitions between annual and perennial life history strategies are common,perennials account for most species in nature because they survive well under year-round stresses.This proportion,however,is reversed in agriculture.Hence,perennial crops promise to likewise protect and enhance the resilience of agricultural ecosystems in response to climate change.Despite significant endeavors that have been made to generate perennial crops,progress is slow because of barriers in studying perennials,and many developed species await further improvement.Recent findings in model species have illustrated that simply rewiring existing genetic networks can lead to lifestyle variation.This implies that engineering plant life history strategy can be achieved by manipulating only a few key genes.In this review,we summarize our current understanding of genetic basis of perenniality and discuss major questions and challenges that remain to be addressed.