Habitat Suitability Index Values Research Articles

Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments.

We developed a habitat suitability index (HSI) model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii) under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, sea surface height anomaly (SSHA) and sea surface salinity (SSS). Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM) were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch), 2008 (average catch) and 2009 (low catch) indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially valuable insights into exploring the relationship between the underlying squid habitat and the inter-annual environmental change.

Distribution of hotspots of chub mackerel based on remote-sensing data in coastal waters of China

Sustainable use of fishery resources requires the effective monitoring and managing of fish stocks and fish habitats. Chub mackerel (Scomber japonicus), distributed in the East China Sea and Yellow Sea, are mainly caught by purse seine fishing fleets from China, Japan, and South Korea. This study used fishery data from Chinese large lighting–purse seine fleets and environmental data including sea surface height (SSH), sea surface temperature (SST) from remote sensing, and temperature gradient derived from SST (GSST) during 1998–2010 to develop habitat suitability index (HSI) models. The HSI models were then used to identify hotspots for chub mackerel for each month. HSI models were developed separately for each of the three distribution areas defined for chub mackerel. According to the frequency distribution of the fishing effort with respect to three environmental variables, suitability index (SI) values were calculated and SI models for each environmental variable were established. The three SI models were combined into two different empirical HSI models: the arithmetic mean model (AMM) and the geometric mean model (GMM). The results showed that the AMM was more suitable than the GMM to estimate the HSI for chub mackerel. The monthly latitudinal variation trend of hotspots was consistent with that of the gravity centres of fishing effort in almost all months. Hotspot maps based on the predicted HSI values were validated by fishery data in 2011. This result indicates that the HSI model based on the AMM can reliably predict hotspots for chub mackerel in the coastal waters of China.

Habitat suitability analysis and identification of potential fishing grounds for swordfish, Xiphias gladius, in the South Atlantic Ocean

Swordfish, Xiphias gladius, is a highly migratory species of important commercial value and widely distributed in three oceans. Recently, the South Atlantic swordfish captured as by-catch in longline fisheries targeting tunas has contributed greatly to the overall Atlantic swordfish's landing. In this study, we have developed a habitat suitability index (HSI) model to examine the relationships between their spatio-temporal distribution and environmental factors and to identify potential fishing grounds for the swordfish in the South Atlantic Ocean using the Taiwanese distant-water longline fishery data and remote-sensing oceanographic data for 1998–2007. All the environmental factors considered – sea surface temperature (SST), mixed layer depth (MLD), sea surface height anomaly (SSHA), chlorophyll-a concentration (CHA) and ocean bathymetry (BAH) – were highly significant with most of the catch-per-unit-effort (CPUE) variation explained by SST. The most optimum habitat (i.e. hotspot) was found in the areas with SSTs of 27–28°C, SSHAs of −0.05 to 0.05 m, CHAs of 0.1–0.2 mg m−3 and BAHs of −4000 to −4500 m. The arithmetic mean model with five environmental variables was found to be the most appropriate according to the information theory based on the evaluation of different empirical HSI models in combination with different environmental factors. The bimonthly geographic information system maps of the predicted HSI values were cross-validated by the observed CPUE, suggesting that the model can be used as a tool for reliable prediction of potential fishing grounds. Because the distribution and relative abundance of swordfish are sufficiently heterogeneous in space and time, the output of this study could provide a scientific basis for time–area closures based management of this species.

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.

Evaluations of seasonal habitat variations of freshwater fishes, fireflies, and frogs using a habitat suitability index model that includes river water temperature

The habitats of aquatic organisms, including freshwater fishes ( Oncorhynchus masou masou, Plecoglossus altivelis altivel, and Cyprinus carpio), fireflies ( Luciola cruciata and Luciola lateralis), and frogs ( Anura sp.), were evaluated dynamically in the Natori River basin in the central Miyagi prefecture in Japan using water temperature as an environmental index. The HSI (habitat suitability index) and WUA (weighted useable area) of aquatic organisms were quantitatively calculated using a distributed runoff model coupled with a heat budget model, land cover data, and digital cartographic data. The results showed that the HSI values of O. masou masou and P. altivelis altivel tended to be high in locations where they were actually observed. The HSI distribution patterns of L. cruciata and L. lateralis showed different results, even though the two species are in the same genus and have similar life cycles. The HSI distribution of Anura sp. returned an average value for the whole basin except for urban and upstream basin areas. In fact, Anura sp. frogs were observed throughout the study basin. Incorporating the dynamic factor of water temperature in the model allowed for monthly evaluations, especially for annual migratory organisms, such as P. altivelis altivel. WUA fluctuations, considering river water temperature, can characterize the annual behavior of P. altivelis altivel and Anura sp., and the partial behavior of O. masou masou.

Modeling a habitat suitability index for the eastern fall cohort of Ommastrephes bartramii in the central North Pacific Ocean

The eastern fall cohort of the neon flying squid, Ommastrephes bartramii, has been commercially exploited by the Chinese squid jigging fleet in the central North Pacific Ocean since the late 1990s. To understand and identify their optimal habitat, we have developed a habitat suitability index (HSI) model using two potential important environmental variables — sea surface temperature (SST) and sea surface height anomaly (SSHA) — and fishery data from the main fishing ground (165°–180°E) during June and July of 1999–2003. A geometric mean model (GMM), minimum model (MM) and arithmetic weighted model (AWM) with different weights were compared and the best HSI model was selected using Akaike’s information criterion (AIC). The performance of the developed HSI model was evaluated using fishery data for 2004. This study suggests that the highest catch per unit effort (CPUE) and fishing effort are closely related to SST and SSHA. The best SST- and SSHA-based suitability index (SI) regression models were SISST-based = 0.7SIeffort-SST + 0.3 SICPUE-SST, and SISSHA-based = 0.5SIeffort-SSHA + 0.5SICPUE-SSHA, respectively, showing that fishing effort is more important than CPUE in the estimation of SI. The best HSI model was the AWM, defined as HSI=0.3SISST-based+ 0.7SISSHA-based, indicating that SSHA is more important than SST in estimating the HSI of squid. In 2004, monthly HSI values greater than 0.6 coincided with the distribution of productive fishing ground and high CPUE in June and July, suggesting that the models perform well. The proposed model provides an important tool in our efforts to develop forecasting capacity of squid spatial dynamics.

서식지 평가 방법을 이용한 바다숲 조성 해역의 적지 선정

A habitat evaluation method was used to estimate the optimum suitability of the study area for the target algae. Habitat evaluation was carried out using an habitat evaluation procedure (HEP) so that the optimum suitability was quantitatively estimated for carrying out marine afforestation in the study area. According to the results of the suitability analysis, the variation of light and wave conditions according to depth showed the factors with the largest impact to involve the spatial distribution of suitable locations within the area. The total suitable area selected was calculated to be 18ha. The quality of the target algae (Ecklonia cava Kjellman) habitat was analyzed using an habitat suitability index (HSI) model of the HEP, which showed 0.55-0.907 (the maximum value being 1.0). This indicated that artificial reefs for afforestation should be installed to zonation type because the suitable area selected (The HSI value was 0.55~0.907) was distributed within the same depth line.

Habitat evaluation of wild Amur tiger ( Panthera tigris altaica) and conservation priority setting in north-eastern China

The Amur Tiger ( Panthera tigris altaica) is one of the world’s most endangered species. Recently, habitat fragmentation, food scarcity and human hunting have drastically reduced the population size and distribution areas of Amur tigers in the wild, leaving them on the verge of extinction. Presently, they are only found in the north-eastern part of China. In this study, we developed a reference framework using methods and technologies of analytic hierarchy process (AHP), remote sensing (RS), geographic information system (GIS), GAP analysis and Natural Break (Jenks) classification to evaluate the habitat and to set the conservation priorities for Amur tigers in eastern areas of Heilongjiang and Jilin Provinces of northeast China. We proposed a Habitat Suitability Index (HSI) incorporating 7 factors covering natural conditions and human disturbance. Based on the HSI values, the suitability was classified into five levels from the most to not suitable. Finally, according to results of GAP analysis, we identified six conservation priorities and designed a conservation landscape incorporating four new nature reserves, enlarging two existing ones, and creating four linkages for Amur tigers in northeast China. The case study showed that the core habitats (the most suitable and highly suitable habitats) identified for Amur tigers covered 35,547 km 2, accounting for approximately 26.71% of the total study area (1,33,093 km 2). However, existing nature reserves protected only (7124 km 2 or) 20.04% of the identified core habitats. Thus, enlargement of current reserves is necessary and urgent for the tiger’s conservation and restoration. Moreover, the establishment of wildlife corridors linking core habitats will provide an efficient reserve network for tiger conservation to maintain the evolutionary potential of Amur tigers facing environmental changes.

Evaluation of Habitat Suitability Models for Forest Passerines Using Demographic Data

ABSTRACT Habitat suitability is often used as a surrogate for demographic responses (i.e., abundance, survival, fecundity, or population viability) in the application of habitat suitability index (HSI) models. Whether habitat suitability actually relates to demographics, however, has rarely been evaluated. We validated HSI models of breeding habitat suitability for wood thrush (Hylocichla mustelina) and yellow‐breasted chat (Icteria virens) in Missouri, USA. First, we evaluated HSI models as a predictor of 3 demographic responses: within‐site territory density, site‐level territory density, and nest success. We demonstrated a link between HSI values and all 3 types of demographic responses for the yellow‐breasted chat and site‐level territory density for the wood thrush. Second, we evaluated support for models containing HSI values, models containing measured habitat features (e.g., tree age, tree species, ecological land type), and models containing management treatments (e.g., even‐aged and uneven‐aged forest regeneration treatments) for each demographic response using model selection. Models containing HSI values received more support, in general, than models containing only habitat features or management treatments for all 3 types of wildlife response. The assumption that changes in habitat suitability represent wildlife demographic response to vegetation change is supported by our models. However, differences in species ecology may contribute to the degree to which HSI values are related to specific demographic responses. We recommend validation of HSI models with the particular demographic data of interest (i.e., density, productivity) to increase confidence in the model used for conservation planning.

Assessing the Effects of Management Alternatives on Habitat Suitability in a Forested Landscape of Northeastern China

Forest management often has cumulative, long-lasting effects on wildlife habitat suitability and the effects may be impractical to evaluate using landscape-scale field experiments. To understand such effects, we linked a spatially explicit landscape disturbance and succession model (LANDIS) with habitat suitability index (HSI) models to assess the effects of management alternatives on habitat suitability in a forested landscape of northeastern China. LANDIS was applied to simulate future forest landscape changes under four management alternatives (no cutting, clearcutting, selective cutting I and II) over a 200-year horizon. The simulation outputs were linked with HSI models for three wildlife species, the red squirrel (Sciurus vulgaris), the red deer (Cervus elaphus) and the hazel grouse (Bonasa bonasia). These species are chosen because they represent numerous species that have distinct habitat requirements in our study area. We assessed their habitat suitability based on the mean HSI values, which is a measure of the average habitat quality. Our simulation results showed that no one management scenario was the best for all species and various forest management scenarios would lead to conflicting wildlife habitat outcomes. How to choose a scenario is dependent on the trade-off of economical, ecological and social goals. Our modeling effort could provide decision makers with relative comparisons among management scenarios from the perspective of biodiversity conservation. The general simulation results were expected based on our knowledge of forest management and habitat relationships of the species, which confirmed that the coupled modeling approach correctly simulated the assumed relationships between the wildlife, forest composition, age structure, and spatial configuration of habitat. However, several emergent results revealed the unexpected outcomes that a management scenario may lead to.

Predictive Value of a Lake Sturgeon Habitat Suitability Model

AbstractAlthough many fish habitat suitability models (HSMs) have been developed and used in wildlife management and conservation planning, comparatively few have been independently validated. Given the importance of such models in habitat management and conservation policy, the extent to which they accurately predict population parameters (e.g., abundance or recruitment) is a critical issue. Here we apply an HSM recently developed for lake sturgeon Acipenser fulvescens in northern rivers to three reaches of the Ottawa River, using measurements of the model's key variables (substrate type, water depth, and velocity) to generate spatially explicit predictions of habitat suitability. We then test the predictive power of the model by comparing lake sturgeon catch per unit effort (CUE) when using short‐set gill nets in areas predicted to have good (habitat suitability index values >0.6) and poor (values < 0.3) adult and juvenile foraging habitats. Consistent with model predictions, significantly more lake sturgeon were caught at sites within river reaches predicted to be of high quality than at those predicted to be of low quality. Moreover, the average CUE at the reach scale correlated positively with the average predicted habitat foraging quality. On the other hand, the predictive power was generally low, such that most of the variation in CUE was unexplained by the fitted models. These results suggest that although the lake sturgeon HSM developed for northern rivers has some predictive power in other contexts, the uncertainty of its predictions is still rather high. We suggest that (1) considerably more effort be devoted to the independent validation of both existing HSMs and those still in development and (2) in the absence of independent validation and bona fide estimates of their predictive power, such models be used circumspectly in conservation management and planning.

Bayesian modelling procedures for the evaluation of changes in wildlife habitat suitability: a case study of roe deer in the Italian Alps

Summary Combining species protection with land management is a central concern for nature conservation but requires a collaborative, problem‐solving approach. Existing procedures do not guarantee the participation of stakeholders in the decision‐making process and, thus, do not necessarily support the development of acceptable management strategies. An analytical framework is required to assess the consequences of human land use for wildlife habitats, incorporating a quantitative structure for including stakeholder opinions. We provide such a framework. As an example, we used the procedure to evaluate the consequences of different building scenarios for the Turin 2006 Winter Olympic Games on potential roe deer Capreolus capreolus habitats. The analysis involved four steps: (i) three Bayesian models were developed to assess the suitability of six study areas for roe deer; (ii) the outcome of the models was converted into a habitat suitability index (HSI) for each study area; (iii) for each area, the building scenario chosen by the Olympic Games organizers was compared with alternative scenarios by means of HSI values; (iv) an HSI value was chosen as a benchmark to evaluate the ecological consequences of landscape changes. The building projects chosen by the Olympic Games organizers caused changes in HSI values in each study area, especially at one site. In three of the six study areas, the chosen projects minimized the loss of suitable roe deer habitat, while in the remaining areas the alternative building locations could have reduced the negative consequences of human activities. Synthesis and applications. A habitat suitablility index calculated with our procedure can be used to (i) compare different hypothetical land‐use scenarios and make decisions about the location of human infrastructures to minimize habitat loss; and (ii) assess the consequences of human activities in relation to an ecological benchmark. The Bayesian approach provides a way to involve local stakeholders in the decision‐making process, and thus is a useful tool for discussion of land‐use policies. Our procedure could be applied to rare and common species and to assessing the consequences of all human activities involving reductions in natural habitat.

Assessment of Habitat Values for Indicator Species and Avian Communities in a Riparian Forest

Habitat suitability index (HSI) models, which are meant to analyze the habitat value of an area for a particular species of interest, are commonly used to evaluate species, communities, and habitats for management or impact assessment. However, many assessments are conducted under strict time and money limitations, and this use of HSI may lead to inappropriate interpretations. The purpose of our work was to evaluate the relationships between three HSI models, the presence of their attendant species, and related avian communities at common assessment time scales. We compared the habitat values of a north Texas bottomland forest measured by HSI models for three species commonly used as indicators of this habitat type, Hairy Woodpecker, Pileated Woodpecker, and Barred Owl, with (1) the actual presence of each species, and (2) the presence of a larger forest-dependent avian community. HSI values did not correlate well with either occurrences of the indicator species or communities for any of the three models. Our results suggest that these models are not necessarily effective indicators of actual habitat use by indicator species, and may not be useful in helping managers make decisions that may affect an entire community related by habitat type. Positive assessments of habitat value through HSI values should be appraised carefully before management decisions are initiated, perhaps through outside review and/or a clear discussion of the context. The primary value of HSI use may be the ability to measure changes in the habitats themselves over time, and not exclusively as representations of species or community presence.

Sensitivity of a white-tailed deer habitat-suitability index model to error in satellite land-cover data: implications for wildlife habitat-suitability studies

Biologists are increasingly using classified satellite data in habitat analyses, especially due to the recent availability of the National Land Cover Dataset (NLCD) and Gap Analysis Project (GAP) classified maps. However, this type of land-cover data may contain substantial class error incorporated during the classification process. Accuracy assessments provide a measure of class-specific error, but they do not provide information on the spatial distribution of error. Error simulation procedures allow users to gauge the sensitivity of their analyses output to errors in the input land-cover data, although these procedures tend to be computationally intensive. We used pixel- and patch-based error simulation to evaluate the effect of class error in the NLCD on the calculation of habitat-suitability index (HSI) values for white-tailed deer (Odocoileus virginianus) in a high-suitability (agricultural) landscape and a low-suitability (forested) landscape. We incorporated error into landscapes at rates reported in the NLCD accuracy assessment for New York and New Jersey using 2 techniques: pixel-based simulations, in which individual pixels were changed from one cover type to another, and patch-based simulations, in which entire patches were changed. Resulting HSI values were higher in all simulated landscapes than in the original landscapes. The largest increase in HSI, 0.57, occurred using a pixel-based simulation in the low-suitability landscape, due partially to increased interspersion and creation of new one-pixel patches. Patch-based simulations provided a more conservative estimate of the effect of error, an increase in HSI of 0.07–0.28. The difference in HSI between pixel- and patch-based error simulations suggests that the spatial distribution of error in land-cover data may strongly affect the calculation of HSI, especially if the model contains habitat variables related to landscape configuration. We suggest that biologists who make use of classified land-cover data evaluate their analyses for potential sensitivity to error, examine confusion matrices provided with accompanying metadata, and conduct error simulations when feasible.

Assessment of the transferability of biological habitat models for Atlantic salmon parr (Salmo salar)

We assessed the transferability of the habitat suitability index (HSI) and the habitat probabilistic index (HPI) between two rivers. Transferability was measured by the ability of HSI and HPI models developed in the Sainte-Marguerite River to predict the distribution of Atlantic salmon parr (Salmo salar) in the Escoumins River. HSI and HPI were based on the pattern of utilization by fish of water depth, current velocity, and substrate size. HSI was developed using the preference curve approach, and HPI was developed using a multiple logistic regression. Predicted values of HSI and HPI in Escoumins River ranged from 0 (poor habitat) to 1 (excellent habitat). Fish density in habitat patches assigned different HSI or HPI values ranged from 0 to 1 fish·100 m–2. Only HPI adequately predicted local variations in parr density (r2 = 0.84) in habitat patches of Escoumins River. Our results suggest that HSI is less transferable between rivers than HPI. Differences in substrate size between the two rivers is suspected to impede the transferability of the HSI model. We also argue that the mathematical structure of HPI provides a larger degree of flexibility that facilitates its transferability and its potential generalization.

Response of Black Bears to Forest Management in the Southern Appalachian Mountains

We evaluated responses of black bears ( Ursus americanus) to changes in habitat in the Pisgah National For- est in North Carolina, USA. Changes in habitat were due to forest management, which affected bear habitat in complex ways. Harvested stands provided plentiful food resources that decreased with regeneration of the canopy. However, their value was offset by a lack of resources associated with mature overstory. Following canopy closure, early-successional food resources in harvested stands tended to decrease, although some soft mast remained more abundant than in unharvested stands. We used a tested Habitat Suitability Index (HSI) to evaluate effects of har- vest management on bear habitat. Values of HSI for harvested stands tended to differ little among young stands and older stands regenerating in pine (Pinus spp.) or hardwood, and all had lower HSI values than unharvested stands. Although effects of roads are modeled negatively in the HSI, proximity of harvested stands to logging roads did not bias comparisons to harvested stands. We used time-series analysis to characterize year-to-year changes on HSI maps for our study area from 1981 through 1994, and designated the results as an index of habitat change. We used this index to evaluate use of changed areas by black bears, estimated from 127 home ranges. Adult females used changed areas inversely proportional to the index of change, whereas adult and juvenile males showed no preferences. With respect to year-to-year variation at the peripheries of their home ranges, adult males and adult females selected habitat patches where suitability had increased and rejected patches where suitability had declined. Home ranges of adult males contained proportionally fewer areas of habitat decline than those of females or juvenile males. Adult females used areas where habitat suitability decreased, proportional to the decrease, but did not prefer them to areas of stable or improved suitability. Adult males appeared to avoid areas of decreased suitability altogether. Forest management positively affected some aspects of bear habitat but had an overall negative effect on habitat suitability in the southern Appalachians. Forest management will not improve bear habitat overall in areas where resources are abundant. Where soft mast is limiting, however, trade-offs between overall habitat suitability and improved productivity of soft mast may be warranted.

HABITAT EVALUATION MODEL FOR GENUS Uca BY USING OF WEIGHTED EVALUATION ITEMS

In this paper, results of analysis on habitat suitability of genus Uca which is selected as a near-threatened specie in Japan were presented. Study sites were tidal flats around SHMOKU Island in Japan.In this study, first, based on the results both of field observations and numerical simulations, data of mud property, characteristics of larvae stage, vegetation and topography feature were collected. Secondary, using multivariate analysis, evaluated items were chosen and were given weighing factor respectively. Thirdly, SI (Suitability Index) curves for each evaluated item were plotted with considering the results of field observations and numerical simulations. Finally, HSI (Habitat Suitability Index) was calculated by multiplying each SI curves score and the HSI value among the tidal fiats was compared. Main results are as follows: 1) Considering not onlyspecies themselves but also surrounding topography is important. 2) Multivariate analysis is effective to select evaluated items. 3) The limited HSI score of Uca arcuata is 0.6 and that of Uca lactea is 0.4.

The performance of alternative spatial objective types in forest planning calculations: a case for flying squirrel and moose

This study examined the characteristics and performance of three different types of spatial objectives in multi-objective forest planning. These types were tested with a case study problem that aimed at improvements in the spatial pattern of the habitats of flying squirrel ( Pteromys volans) and moose ( Alces alces). In the first step, the habitats were determined by using a stand-level habitat suitability index (HSI). Stands in which the HSI exceeded a user-specified limit were considered as habitats. In the forest level problem formulations, the spatial objective types were included in the multi-objective forest-planning model, which was solved by using a heuristic optimization technique. The first type of spatial objective was the proportion of a specified type of stand boundary of the total boundary length. For flying squirrel, the aim was to increase the boundaries between neighboring stands, which were both suitable for breeding and foraging. For moose, the aim was to increase the amount of edge, i.e. the boundary between winter-foraging habitats and other areas. The second spatial objective type was the spatial autocorrelation of HSI. It was maximized for flying squirrel and minimized for moose. Whereas maximization of spatial autocorrelation tends to cluster similar stands, its minimization produces a pattern where neighboring stands often have different characteristics. The third spatial objective type was a weighted mean of the stand-level HSI. The weight depended on the stand location being highest for current habitat patches and decreased as the distance to them increased. This objective, which tends to cluster habitat patches, was applied to flying squirrel only. The spatial objective types were tested in six forest areas located in north Karelia, Finland, ranging from 404.6 to 984.8 ha in area. The first spatial objective resulted in a large area of habitat exceeding the threshold HSI value with a good spatial pattern. The second spatial objective yielded a clearly lower total habitat area but a good spatial pattern, and a good connectivity of the flying squirrels’ habitats. The third objective resulted in a slightly improved spatial pattern of the flying squirrels’ habitats.

HABITAT EVALUATION MODEL FOR GENUS UCA IN SHIKOKU ISLAND

The purpose of this study is to use HEP (Habitat Evaluation Procedure) for studying rare species on tidal flats and to evaluate the value of tidal flats themselves. In this study, based on the results both of field observations and numerical simulations, SI (Suitability Index) curves for each mud property and physical factors such as friction velocity were plotted. Then, HSI (Habitat Suitability Index) for each tidal flat was calculated by multiplying each SI curves score and comparing the HSI value among the tidal flats. The following results were obtained: 1) The Yoshino River mouth, which is the largest habitat of genus Uca in Shikoku Lsland, had the highest SI score. 2) The suitability of habitation for other kinds of tidal-living crabs may be estimated as the Yoshino River also had the highest score. Using this method, the value of tidal flats could be discussed indirectly, that is, as the HSI score becomes larger, the necessity of tidal flats becomes great.

Manipulative, Multi-Standard Test of a White-Tailed Deer Habitat Suitability Model

Despite widespread use of habitat suitability index (HSI) models, testing has been limited in 2 areas that are of critical importance. First, while HSI models are commonly employed to predict the effects of hypothetical landscape manipulations, their predictive ability before and after a landscape manipulation is rarely evaluated. Second, model performance typically is compared to a single standard (e.g., density). If this standard does not reflect every way in which the animals use habitat, then management based on models calibrated according to the single standard may be flawed. I compared the predictions of an HSI model (summer, winter, and total) for white-tailed deer (Odocoileus virginianus) against 2 standards (foraging intensity and pellet-group count) before and after a timber harvest and in the presence and absence of hunting traffic. HSI (total model) values were significantly positively correlated to foraging intensity before, but not after, the timber harvest. The winter model was always significantly positively correlated with pellet-group count (r s ≥ 0.195). However, the total model was significantly (but negatively) correlated (r s ≤ -0.132) with pellet-group count in all conditions except in the presence of hunting traffic. The unreliable predictive ability of the model tested in this study emphasizes the caution with which HSI models should be applied and the need for further multi-standard, manipulative studies.