Importance of Weighting for Multi-Variable Habitat Suitability Index Model: A Case Study of Winter- Spring Cohort of Ommastrephes bartramii in the Northwestern Pacific Ocean

Weighting values for different habitat variables used in multi-factor habitat suitability index (HSI) modeling reflect the relative influences of different variables on distribution of fish species. Using the winter-spring cohort of neon flying squid (Ommastrephes bartramii) in the Northwestern Pacific Ocean as an example, we evaluated the impact of different weighting schemes on the HSI models based on sea surface temperature, gradient of sea surface temperature and sea surface height. We compared differences in predicted fishing effort and HSI values resulting from different weighting. The weighting for different habitat variables could greatly influence HSI modeling and should be carefully done based on their relative importance in influencing the resource spatial distribution. Weighting in a multi-factor HSI model should be further studied and optimization methods should be developed to improve forecasting squid spatial distributions.

Balancing timber production and habitat conservation of Okinawa Rails(Gallirallus okinawae): Application of a harvest scheduling optimization model in subtropical forest in Okinawa, Japan

Finding the right balance between timber production and the management of forest-dependent wildlife species,present a difficult challenge for forest resource managers and policy makers in Okinawa,Japan.A possible explanation of this can be found in the unique nature of the forest management area which is populated with various kinds of rare and endangered species.This issue has been brought to light as a result of the nomination of northern Okinawa Island in 2018 as a candidate for World Natural Heritage site.The nomination has raised public awareness to the possibility of conflicting management objectives between timber extraction and the conservation of habitat for forest-dependent wildlife species.Managing exclusively for one objective over the other may fail to meet the demand for both forest products and wildlife habitat,ultimately jeopardizing the stability of human and wildlife communities.It is therefore important to achieve a better balance between the objective of timber production and conservation of wildlife habitat.Despite the significance of this subject area,current ongoing discussions on how to effectively manage for forest resources,often lack scientific basis to make sound judgement or evaluate tradeoffs between conflicting objectives.Quantifying the effect of these forest management activities on wildlife habitat provides useful and important information needed to make forest management and policy decisions.In this study we develop a spatial timber harvest scheduling model that incorporates habitat suitability index(HSI)models for the Okinawa Rail(Gallirallus okinawae),an endangered avian species found on Okinawa,Japan.To illustrate how the proposed coupling model assembles spatial information,which ultimately aids the study of forest management effects on wildlife habitat,we apply these models to a forest area in Okinawa and conduct a simple simulation analysis.

Influence of environmental data of different sources on marine species habitat modeling:A case study for Ommastrephes bartramii in the Northwest Pacific Ocean

The quality of environmental data and its possible impact on the marine species habitat modelling are often overlooked while the sources for these data are increasing.This study selected sea surface temperature(SST)from two commonly used sources,the NOAA Ocean Watch and IRI/LDEO Climate Data Library,and then constructed habitat suitability index model to evaluate the influences of SST from the two sources on the outcomes of Ommastrephes bartramii habitat models for the months of July–October in the Northwest Pacific Ocean during 1996–2012.This study examined the differences in the amount of estimated unfavourable/favourable habitat area when the SST used for model building and inference were the same or different.Dynamics in suitable habitat area calculated from SST was insensitive to the two different SST products.In the fishing season of O.bartramii,the changes of magnitude and trend of monthly suitable habitat area in August and September were similar over time,whereas there were large differences for July and October.Importantly,there is a substantial lack of consistency in the O.bartramii habitat distribution based on SST of two sources.This study considered the sources of environmental data for habitat modelling and then inferred species habitat distribution whether by the same or different data source.

Habitat suitability analysis of eelgrass Zostera marina L. in the subtidal zone of Xiaoheishan Island

We present a GIS-based habitat suitability index(HSI) model to identify suitable areas for Zostera marina L. restoration in the subtidal zone of Xiaoheishan Island. The controlling factors in the model,in order of importance,are Secchi depth,sediment composition,water temperature,salinity,current velocity,water depth and nutrient quality. Specific factor piecewise functions have been used to transform parameter values into normalized quality indexes. The weight of each factor was defined using expert knowledge and the analytic hierarchy process(AHP) method. All of the data thus obtained were interpolated using the inverse distance weighted(IDW) interpolation method to create maps for the entire region. In this study,the analysis of habitat suitability in the subtidal zone of Xiaoheishan Island was conducted for four seasons. According to the GIS-based HSI model,the optimal habitat of Z ostera marina L. appears in spring,although habitat remains suitable all year round. On the whole,the optimum site for eelgrass restoration is located in the eastern region,followed by the western and southern regions. We believe that the GIS-based HSI model could be a promising tool to select sites for Z ostera marina L. restoration and could also be applicable in other types of habitat evaluation.