EVOLUTIONARY DYNAMIC MODEL OF POPULATION WITH NICHE CONSTRUCTION AND ITS APPLICATION RESEARCH

Based on the theories and approaches in biomechanics, the mechanism and pattern of niche construction were discussed systematically. Through establishing the spatial pattern of niche and its measuring-fitness formula, and the dynamic system models of single- and two-population with niche construction, including corresponding theoretical analysis and numerical simulation on their evolutionary dynamics of population and the mechanism of competitive coexistence, the co-evolutionary relationship between organisms and their environments was revealed. The results indicate that population dynamics is governed by positive feedback between primary ecological factors and resource content. Niche construction generates an evolutionary effect in system by influencing the fitness of population. A threshold effect exists in single population dynamic system, in dynamic system of two competitive populations, niche construction can lead to alternative competitive consequences, which may be a potential mechanism to explain the competitive coexistence of species.

The Aircraft Industry in Japan： Niche Construction and Patent Portfolio Strategy

The Japanese aircraft industry changed its course in approximately 2007. Mitsubishi Heavy Industry （MHI） Co. launched a project in which regional jets （Mitsubishi Regional Jet （MILl）） reentered the airliner manufacturing market. Honda announced plans to develop, manufacture, and sell small passenger jets, or Honda Jets, in the United States （US） market. This paper summarizes the historical development of the industry using aircraft production statistics and analyzes the patent portfolio strategy from 1995 to 2006, a period in which MHI and Honda accumulated patents for the upcoming market entry. The author uses the following two measurements to evaluate niche widths among aircraft manufacturing companies： the Morishita＇s index and the principal component analysis. The former index is used in population ecology to measure overlapping species. The latter measurement is presented to clarify the validity of the Morishita＇s index. The author identifies MHI as a market leader, Kawasaki Heavy Industry （KHI） Co. as a challenger, Fuji Heavy Industry （FHI） Co. as a follower, and Honda as a nicher in the aircraft patent portfolio strategy in Japan.

Invasion syndromes:hypotheses on relationships among invasive species attributes and characteristics of invaded sites

As invasion science accepts that there is no single causal factor for biological invasion, the identification of groups of traits that are often associated, or ＂syndromes＂, is a logical move forward. Invasion syndromes are proposed to identify suites of site conditions （biotic and environmental） that render a site vulnerable to invasion by different types of invaders. This paper proposed four invasion syndromes which relate invader attributes （competitive ability, niche construction, phenotypic plasticity, and phenological niche separation） to the biotic characteristics （biodiversity and enemies） and environmental conditions （resource abundance and fluctuation） of invaded sites. The four invasion syndromes described in this paper are a development of hypotheses of how the many factors that influence species invasion might be associated. Invasion Syndrome 1 proposes that sites with relatively high resource abundance and high diversity should be vulnerable to invasion by species with high competitive ability. Invasion Syndrome 2 hypothesizes that sites with relatively low resource abundance and low diversity should be vulnerable to invasion by species with niche construction ability. Invasion Syndrome 3 postulates that sites with moderate or fluctuating resources and moderate diversity should be vulnerable to invasion by species with high phenotypic plasticity. Invasion Syndrome 4 hypothesizes that species introduced into a site where it has phenological niche separation from natives will not have to contend with interference from the biotic community at a site （diversity or natural enemies） and may invade where ever site environmental conditions suit its life history. Further work is needed to support, contradict, or refine these hypotheses and almost certainly will identify more invasion syndromes.

Pollination interactions reveal direct costs and indirect benefits of plant-plant facilitation for ecosystem engineers

Aims Ecosystem engineers substantially modify the environment via their impact on abiotic conditions and the biota,resulting in facilitation of associated species that would not otherwise grow.Yet,reciprocal effects are poorly understood as studies of plant–plant interactions usually estimate only benefits for associated species,while how another trophic level may mediate direct and indirect feedback effects for ecosystem engineers is hardly considered.Methods We ran a field experiment with two ecosystem engineers(Arenaria tetraquetra and Hormathophylla spinosa)blooming either alone or with associated plants to decompose net effects and to test the hypothesis that pollinator-mediated interactions provide benefits that balance costs of facilitation by ecosystem engineers.Important Findings We found that net costs of facilitation are accompanied by pollinator-mediated benefits.Despite ecosystem engineers producing fewer flowers per plant,they were visited by more and more diverse pollinators per flower when blooming with associated plants than when blooming alone.Although seed production per plant was higher when ecosystem engineers bloomed alone,fruit set and seed set varied between species.In one case(A.tetraquetra),fruit and seed sets were negatively affected by the presence of associated plants,whereas,in another case(H.spinosa),fruit set and seed set were higher and unaffected when ecosystem engineers bloomed with associated plants,respectively.Our findings suggest that besides experiencing direct costs,ecosystem engineers can also benefit from facilitating other species via increasing their own visibility to pollinators.Thus,we highlight that pollination interactions can compensate for costs of facilitation depending on ecosystem engineer species.This study illuminates how the outcome of direct plant–plant interactions might be mediated by indirect interactions including third players.

Invasive grasses consistently create similar plant-soil feedback types in soils collected from geographically distant locations

Aims Plants of similar life forms and closely related species have been observed to create similar types of plant–soil feedbacks(PSFs).However,investigations of the consistency of PSFs within species have not yielded clear results.For example,it has been reported that species create different types of PSFs in their native and introduced ranges.The aim of this project is to examine if four species create similar PSF types from soils collected from widely distributed areas within their introduced range.The soil for this project was collected from three areas in western North America.With this design,we aim to determine species-and site-specific ability to create PSFs and if the type of PSF created is consistent in all soil from all three collection areas.The species examined are Agropyron cristatum,Centaurea solstitialis,Poa pratensis and Taeniatherum caput-medusae.Methods We used three-field collected soils(from northern Nevada,western Montana and eastern Montana)in a two-phase greenhouse experiment to quantify the type of PSFs created by four invasive species.The first phase was a conditioning phase wherein each invasive species created species-specific changes to the soil.The second phase of the experiment was the response phase wherein both the conditioning species and a native phytometer were grown in the conditioned soil and in unconditioned(control)soil.The final aboveground biomass was used to evaluate the effect of conditioning and to determine the type of PSF created by each invasive species.Important Findings Our results suggest that three of our four study species did show consistency in relation to PSF.Two species A.cristatum and T.caputmedusae consistently created PSF types that benefit conspecifics more than heterospecifics(and thus are‘invasive’PSF types)and P.pratensis consistently exhibited no,or‘neutral’,feedbacks.The fourth species(C.solstitialis)was inconsistent:in one soil,no feedback was created;in other soil,an invasive PSF was created and in the last soil,a feedback that relatively benefited the native phytometer was created.Thus,PSFs appear to uniformly contribute to the success of two species(A.cristatum and T.caput-medusae)but not C.solstitialis nor P.pratensis.