In the bird species, 44 percent of species are residents on the island, while the rest are seasonal migrators: winter birds migrating from north to the island during autumn and winter for overwintering (40%), summer birds migrating from south to the island during spring and summer for breeding (2.0%), and transient migrators stopping off briefly on the island during migration from north to further south of the island (4.0%: Takano, 1982; Committee for Check-List of Japanese Birds, 2000). The relative abundances of principal bird species observed in prey censuses during each season were derived. During all seasons, four species of resident birds, *H. amaurotis*, *S. orientalis*, *C. macrorhynchos*, and *Parus* spp., were relatively abundant. Meanwhile, during autumn and winter, two groups of migrators, *Turdus* spp. and ducks, were also abundant, which occupied respectively high proportions

Among the amphibians, in spring to autumn, *F. limnocharis* was the most abundant, followed by *M. ornata*, *B. japonica*, and *C. eiffingeri*. Meanwhile, *M. ornata* was the most abundant during winter, followed by *F. limnocharis*, *R. supranarina*, *C. eiffingeri*, and *Rh.*

To assess seasonal variation of more general compositions of prey availability, I calculated seasonal variations of frequency occurrences of 18 major prey groups in prey censuses which were also frequently eaten by the cat. The results are summarized in Table 2. Some prey groups including taxonomically similar prey species (ducks in the family Anatidae, the genera of egrets *Egretta* spp., thrushes *Turdus* spp., skinks *Eumeces* spp., cockroaches *Rhabdoblatta* spp., and camel crickets *Diestrammena* spp.) were combined within the

Frequency occurrence of 14 prey groups showed significant seasonal variations (*G*-test, *P* < 0.05). Although other groups, water hens, *S. orientalis*, *T. elegans*, and *R. supranarina*, thrushes, and *J. polygonata*, did not show significant seasonal variations (*G*-test, *P* > 0.05),

A more detailed picture of seasonality of prey availability of the cat emerges from applying a *PCA* model to the data matrix in Table 2. The first and second principal components of *PCA* explained 61.2% and 25.0% of the total variability, respectively, and the scores of the first and second factors are presented in Table 3. In the score plot of each prey species on factors, the main variables ordering the various species along factor 1 were "wintersummer", and those ordering the species along factor 2 were "spring-autumn", which were

these frequency occurrences also differed among seasons in varying degrees.

sufficient to illustrate the main structure of prey availability among seasons (Fig. 3).

The overall frequency of occurrence in each taxon was calculated as follows: 30.9% in mammals, 47.7% in birds, 33.1% in reptiles, 34.3% in amphibians, 2.96% in fish, 24.3% in insects, 4.22% in crustaceans, and 3.27% in others.

#### **3.3 Prey preference**

I calculated Jacobs' electivity indices for 18 bird groups in which taxonomically similar species with a small number of samples were combined, and for seven amphibian species (Table 1). The result show that the cat preferred preying on some bird items; egrets, rails (*R. eurizonoides* and *A. phoenicurus*), *Halcyon coromanda*, and wagtails in the genus *Motacill*a, all of which were terrestrial foragers. However, *Hirundo tahitica*, *Pericrocotus divaricatus*, *H. amaurotis*, *Cettia diphone*, *Terpsiphone atrocaudata*, *Parus* spp., *Zosterops japonica*, and *Passer montanus*, all of which were arboreal foragers, were not preferred or were avoided by the cat.

Among amphibians, the cat preferred preying on *R. supranarina* and *Rh. owstoni* while *R. psaltes*, *C. eiffingeri*, *B. japonica*, *F. limnocharis*, and *M. ornata* were not preferred or was avoided for predation by the cat (Table 1).

Table 1. Prey preferences of 25 prey items by the Iriomote cat, indicated by Jacobs (1974) electivity index (*D*). \*1Principal habitat of each species: arboreal (A), terrestrial (T), and both (A, T), depending on where species were often observed during the censuses. \*2Migration of each species; residents (R), summer migrators (S) and winter migrators (W), according to Takano (1982) and Committee for Check-List of Japanese Birds (2000). \*3Estimated liveweight from weighing my reference collection or Imaizumi et al. (1977).

## **3.4 Seasonal variation**

472 Diversity of Ecosystems

The overall frequency of occurrence in each taxon was calculated as follows: 30.9% in mammals, 47.7% in birds, 33.1% in reptiles, 34.3% in amphibians, 2.96% in fish, 24.3% in

I calculated Jacobs' electivity indices for 18 bird groups in which taxonomically similar species with a small number of samples were combined, and for seven amphibian species (Table 1). The result show that the cat preferred preying on some bird items; egrets, rails (*R. eurizonoides* and *A. phoenicurus*), *Halcyon coromanda*, and wagtails in the genus *Motacill*a, all of which were terrestrial foragers. However, *Hirundo tahitica*, *Pericrocotus divaricatus*, *H. amaurotis*, *Cettia diphone*, *Terpsiphone atrocaudata*, *Parus* spp., *Zosterops japonica*, and *Passer montanus*, all of which were arboreal foragers, were not preferred or were avoided by the cat. Among amphibians, the cat preferred preying on *R. supranarina* and *Rh. owstoni* while *R. psaltes*, *C. eiffingeri*, *B. japonica*, *F. limnocharis*, and *M. ornata* were not preferred or was

Ardeidae Egrets T R,W >500 176 (9.2) 22 (12.7) 0.18 + Anatidae Ducks T R,W >500 131 (6.8) 15 (8.7) 0.13 + Rallidae Rails T R 200 49 (2.6) 48 (27.7) 0.87 + Scolopacidae Snipes T W 200 21 (1.1) 2 (1.2) 0.03 + Columbidae Pigeon A,T R 200 260 (13.6) 21 (12.1) -0.07 - Strigidae Owls A R 120 89 (4.7) 6 (3.5) -0.15 - Alcedinidae *Halcyon coromanda* T S 100 18 (0.9) 6 (3.5) 0.58 + Hirundinidae *Hirundo tahitica* A W 20 22 (1.2) - Motacillidae *Motacilla* spp. T W 30 34 (1.8) 7 (4.0) 0.40 + Campephagidae *Pericrocotus divaricatus* A R 20 26 (1.4) - Pycnonotidae *Hypsipetes amaurotis* A R 30 386 (20.2) 2 (1.2) -0.91 - Turdidae *Turdus* spp. T W 80 159 (8.3) 27 (15.6) 0.34 + Sylviidae *Cettia diphone* A R 20 61 (3.2) - Monarchidae *Terpsiphone atrocaudata* A R 20 23 (1.2) - Paridae *Parus* spp. A R 20 150 (7.8) 2 (1.2) -0.76 - Zosteropidae *Zosterops japonica* A R 20 87 (4.6) 2 (1.2) -0.61 - Ploceidae *Passer montanus* A R 20 36 (1.9) - Corvidae *Corvus macrorhynchos* A,T R 300 183 (9.6) 13 (7.5) -0.13 -

Liveweight

1 Migration\*2 Available Consumed

Ranidae *Rana supranarina* T 60 27 (0.5) 7 (2.8) 0.69 +

Rhacophoridae *Rhacophorus owstoni* A,T 20 68 (1.3) 55 (22.3) 0.91 +

Microhylidae *Microhyla ornata* T 4 526 (10.4) 29 (11.7) 0.07 +

Table 1. Prey preferences of 25 prey items by the Iriomote cat, indicated by Jacobs (1974) electivity index (*D*). \*1Principal habitat of each species: arboreal (A), terrestrial (T), and both (A, T), depending on where species were often observed during the censuses. \*2Migration of each species; residents (R), summer migrators (S) and winter migrators (W), according to Takano (1982) and Committee for Check-List of Japanese Birds (2000). \*3Estimated liveweight from weighing my reference collection or Imaizumi et al. (1977).

*Rana psaltes* T 10 128 (2.5) - *Fejervarya limnocharis* T 20 3,386 (67.1) 142 (57.0) -0.20 -

*Chirixalus eiffingeri* A 4 242 (4.8) - *Buergeria japonica* T 4 669 (13.3) 14 (5.7) -0.44 -

Electivity Preference

*N* (%) *N* (%) Index (*D* )

insects, 4.22% in crustaceans, and 3.27% in others.

avoided for predation by the cat (Table 1).

(g)\* Prey item Habitat\* 3

**3.3 Prey preference**

Bird;

Frog;

## **3.4.1 Prey availability**

The frequency of occurrence of most species changed seasonally. Within an identified 72 species found in the PTLs, 66 species were absent in some periods or present in limited periods of the study years. Although six species, *S. orientalis*, *H. amaurotis*, and *C. macrorhynchos*, of birds, and *B. japonica* and *M. ornata* of amphibians, and *Diestrammena* spp. of insects, were found in all the study periods, these frequencies also largely varied depending on season.

In the bird species, 44 percent of species are residents on the island, while the rest are seasonal migrators: winter birds migrating from north to the island during autumn and winter for overwintering (40%), summer birds migrating from south to the island during spring and summer for breeding (2.0%), and transient migrators stopping off briefly on the island during migration from north to further south of the island (4.0%: Takano, 1982; Committee for Check-List of Japanese Birds, 2000). The relative abundances of principal bird species observed in prey censuses during each season were derived. During all seasons, four species of resident birds, *H. amaurotis*, *S. orientalis*, *C. macrorhynchos*, and *Parus* spp., were relatively abundant. Meanwhile, during autumn and winter, two groups of migrators, *Turdus* spp. and ducks, were also abundant, which occupied respectively high proportions of the avifauna.

Among the amphibians, in spring to autumn, *F. limnocharis* was the most abundant, followed by *M. ornata*, *B. japonica*, and *C. eiffingeri*. Meanwhile, *M. ornata* was the most abundant during winter, followed by *F. limnocharis*, *R. supranarina*, *C. eiffingeri*, and *Rh. owstoni*.

To assess seasonal variation of more general compositions of prey availability, I calculated seasonal variations of frequency occurrences of 18 major prey groups in prey censuses which were also frequently eaten by the cat. The results are summarized in Table 2. Some prey groups including taxonomically similar prey species (ducks in the family Anatidae, the genera of egrets *Egretta* spp., thrushes *Turdus* spp., skinks *Eumeces* spp., cockroaches *Rhabdoblatta* spp., and camel crickets *Diestrammena* spp.) were combined within the taxonomical group and the data were pooled.

Frequency occurrence of 14 prey groups showed significant seasonal variations (*G*-test, *P* < 0.05). Although other groups, water hens, *S. orientalis*, *T. elegans*, and *R. supranarina*, thrushes, and *J. polygonata*, did not show significant seasonal variations (*G*-test, *P* > 0.05), these frequency occurrences also differed among seasons in varying degrees.

A more detailed picture of seasonality of prey availability of the cat emerges from applying a *PCA* model to the data matrix in Table 2. The first and second principal components of *PCA* explained 61.2% and 25.0% of the total variability, respectively, and the scores of the first and second factors are presented in Table 3. In the score plot of each prey species on factors, the main variables ordering the various species along factor 1 were "wintersummer", and those ordering the species along factor 2 were "spring-autumn", which were sufficient to illustrate the main structure of prey availability among seasons (Fig. 3).

Ecological Flexibility of the Top Predator in an

more abundant in autumn and winter.

also greatly varied on a monthly basis.

**3.4.2 Predation by the cat**

**Mammals**

**Birds**

**Reptiles**

**Amphibians**

**Insects**

Island Ecosystem – Food Habit of the Iriomote Cat 475

*Pteropus dasymallus* (Yaeyama flying fox) -0.072 0.920 0.004 0.773 *Rattus rattus* (black rat) - - 0.027 0.665

Prey items Availability Predation

Egrets 0.059 -0.553 -0.888 0.138 Ducks -0.882 -0.239 -0.639 -0.709 Water hens 0.929 -0.161 0.393 -0.771 *Streptopelia orientalis* (Oriental turtle dove) 0.659 -0.737 0.896 0.301 *Turdus* spp. (thrushes) -0.978 0.025 -0.920 0.379 *Corvus macrorhynchos* (jungle crow) 0.899 0.256 0.774 -0.617

*Japalura polygonata* (Sakishima tree lizard) 0.940 0.324 0.930 0.211 *Eumeces* spp. (skinks) 0.938 0.068 0.476 -0.802 *Trimeresurus elegans* (viper) 0.954 -0.116 0.317 0.771

*Rana supranarina* (large tip-nosed frog) -0.003 0.614 0.902 -0.016 *Fejervarya limnocharis* (Indian rice frog) 0.991 -0.102 0.695 -0.676 *Rhacophorus owstoni* (Owston's green tree frog) -0.964 0.266 -0.366 0.826 *Buergeria japonica* (Ryukyu kajika frog) 0.837 -0.476 0.505 0.663 *Microhyla ornata* (Ornata narrow-mouthed toad) -0.824 -0.563 -0.156 0.973

*Rhabdoblatta* spp. (spotted cockroaches) 0.797 -0.576 0.736 -0.624 *Diestrammena* spp. (camel crickets) 0.359 0.927 -1.000 0.012 *Cardiodactylus novaeguineae* (spotted cricket) 0.657 0.592 -0.927 0.369 Eigenvalue 11.01 4.51 10.07 5.93 % Explained variance 61.17 25.05 53.02 31.20

Table 3. Results of principle component analysis for seasonal variations of availability and predation of principal prey items found in prey censuses and scats of the Iriomote cat.

Ducks and *M. ornata* were the most abundant in winter. Egrets were the most abundant in spring. *Streptopelia orientalis*, *Rhabdoblatta* spp., *B. japonica*, water hens, *T. elegans*, *F. limnocharis*, *Eumeces* spp., *C. macrorhynchos*, and *J. polygonata*, were more abundant in spring and summer. *Cardiodactylus novaeguineae*, *Diestrammena* spp., *R. supranarina*, *P. dasymallus*, were more abundant in summer and autumn. *Rhacophorus owstoni* and *Turdus* spp. were

The frequency occurrence of most prey species in scat contents changed monthly or seasonally. Within an identified 76 prey items in the scat content, 72 prey items were absent in some months or present in limited months of the years. Although four species, black rats, flying foxes, rice frogs, and freshwater prawns, were found at all months, these frequencies

Factor 1 Factor 2 Factor 1 Factor 2

Fig. 3. Seasonal variation of potential prey availability and diet of the Iriomote cat. Two dimensional-plots of scores for each prey items on first two factors using *VARIMAX* rotation model *PCA*s showing mainly four season prey groups. PD: *Pteropus dasymallus*, RR: *Rattus rattus*, CM: *Corvus macrorhynchos*, Du: ducks, Eg: egrets, SO: *Streptopelia orientalis*, Tu: *Turdus* spp., WH: water hens, Eu: *Eumeces* spp., JP: *Japalura polygonata*, TE: *Trimeresurus elegans*, BJ: *Buergeria japonica*, MO: *Microhyla ornata*, FL: *Fejervarya limnocharis*, RS: *Rana supranarina*, RO: *Rhacophorus owstonii*, Di: *Diestrammena* spp., Rh: *Rhabdoblatta* spp., CN: *Cardiodactylus novaeguineae*.

Table 2. Seasonal variations of availability and predation of principal prey items observed in prey censuses and found in scats of the Iriomote cat. \* *P* < 0.05; \*\* *P* < 0.001.

Availability

0.0

PD RS Di CN

Automn - Winter

Summer - Automn

Facrtor 1

0.5

1.0

1.0

*novaeguineae*.

**Mammals**

**Birds**

**Reptiles**

**Amphibians**

**Insects**

0.5 0.0 -0.5 -1.0

FL WH

*Rattus rattus* (black rat) 17.7 19.0 13.4 26.2 20.2 11.8 0.008 \*

Spring - Summer

Du MO

Winter

Eg

Spring

SO Rh TE BJ

Facrtor 2

JPCM Eu

RO Tu

CN

Tu

1.0

0.5

0.0

Facrtor 2

Fig. 3. Seasonal variation of potential prey availability and diet of the Iriomote cat. Two dimensional-plots of scores for each prey items on first two factors using *VARIMAX* rotation model *PCA*s showing mainly four season prey groups.  Seasonal variations of availability and predation of principal prey items observed in

Number of examined scats 311 189 134 313 947 Night 34.38 39.07 26.14 32.40 132

prey censuses and found in scats of the Iriomote cat. \* *P* < 0.05; \*\* *P* < 0.001.

RO

Automn - Winter

Winter

Di

Eg

Du

Spring SummerAutumn Winter Overall *G P* Spring SummerAutumn Winter Overall *G P*

Distance (km)

Rh

FL Eu

WH

Spring - Summer RS

CM

JP

SO

BJ

Spring

Winter - Spring

TE

RR

Facrtor 1

Day 38.32 44.78 24.83 13.92 122

Total 72.70 83.85 50.97 46.32 254

MO PD

Predation

Table 3. Results of principle component analysis for seasonal variations of availability and predation of principal prey items found in prey censuses and scats of the Iriomote cat.

Ducks and *M. ornata* were the most abundant in winter. Egrets were the most abundant in spring. *Streptopelia orientalis*, *Rhabdoblatta* spp., *B. japonica*, water hens, *T. elegans*, *F. limnocharis*, *Eumeces* spp., *C. macrorhynchos*, and *J. polygonata*, were more abundant in spring and summer. *Cardiodactylus novaeguineae*, *Diestrammena* spp., *R. supranarina*, *P. dasymallus*, were more abundant in summer and autumn. *Rhacophorus owstoni* and *Turdus* spp. were more abundant in autumn and winter.

## **3.4.2 Predation by the cat**

The frequency occurrence of most prey species in scat contents changed monthly or seasonally. Within an identified 76 prey items in the scat content, 72 prey items were absent in some months or present in limited months of the years. Although four species, black rats, flying foxes, rice frogs, and freshwater prawns, were found at all months, these frequencies also greatly varied on a monthly basis.

Ecological Flexibility of the Top Predator in an

influence the feeding habits of the Iriomote cat.

of food requirement for reproduction of the cat.

contribute to supply a deficiency of food resource during winter.

Island Ecosystem – Food Habit of the Iriomote Cat 477

on arboreal species such as *H. amaurotis* and *Parus* spp., suggesting the Iriomote cats arboreal activities. However, prey preferences of the cat for arboreal birds were much lower than those for terrestrial foraging bird species. Thus, I support the prediction of Sakaguchi & Ono (1994) that the cat is a species foraging mainly on the ground, as opposed to in trees.

Species compositions of avifauna as potential prey resources of the cat drastically changed in relation to migrations of birds. This island with such abundant small vertebrates is known as a way station or breeding place for many migrant birds; 191 species belonging to 15 orders, 43 families, and 106 genera are recorded on this island, 83% of which are seasonal migrators while resident bird species occupy at least 17% of the total avifauna on the island (Okinawa Prefectural Education, 1985). In the cat diet, these avian prey items were present at high frequency. Thus, I presumed that such drastic seasonal changes of potential food resources of the cat in relation to migrations of large numbers of birds would strongly

Consequently, bird migrations largely affected the cat diet, particularly during winter by some migrators such as *Turdus* spp., ducks, *Motacilla* spp., and egrets. Most species of resident birds on the island breed during spring and summer (Takano, 1985); many juvenile birds were observed from June to August during the prey censuses. Particularly, *A. phoenicurus* and *C. macrorhynchos* were frequently preyed upon during spring and summer. It is likely that more vulnerable juveniles were frequently eaten during these periods. Although reptiles are principal prey items during spring and summer, the availability of this prey decrease during winter due to their low physiological activity under low temperature (Sakaguchi & Ono, 1994). It is, therefore, likely that the migrations of winter birds largely

In dietary studies of other *P. bengalensis* populations, the cat diet is monopolized by mammalian prey in a continental habitat (Thailand), bird prey were present at less than 2% of their scats (Rabinowitz, 1990). On an island site, Tsushima Islands, Japan, although mammalian prey are also the most important food in the diet, the cat also preys heavily on birds (41.7% for the frequency of occurrence in the scats: Inoue, 1972). Unfortunately, there is little available information for diets of other wild felids on island sites. However, I could find those of feral domestic cat, *Felis catus*, populations which are widespread all over the world, and they had been introduced to many islands (Fitzgerald & Tuner, 2000). Dietary studies of domestic cats on continents show that mammals are usually the main prey eaten by cats, while birds are much less important than mammals. However, birds are much more important in the diet of domestic cats on islands than on continents. Particularly, on islands where seabirds are recorded in the diet, birds are present on average at 60% of frequency of occurrence in their scats (Fitzgerald & Tuner, 2000). Although small mammals such as rodents or lagomorphs are available on many islands, feral cat populations can persist on islands that lack mammalian prey but are abundant in birds (Kirkpatrick & Rauzon, 1986). Therefore, I suggest that the Iriomote cat can endure on its small island despite a poor mammalian fauna by means of shifting principal prey items to seasonal migrators, particularly during winter. It is during this winter period, that the mating season of the cat takes place(Okamura et al., 2000); home range size and activity of male cats increase (Nakanishi et al., 2005; Schmidt et al., 2003, 2009). Thus, the food requirement of the cat should increase in that time. Therefore, it is likely that winter migrators supply an increment

The frequency occurrences for each season of 19 major prey groups which were frequently found in the scats were calculated, and the seasonal variations were compared among seasons (Table 2). Fifteen groups of the prey items showed significant seasonality (*G*-test, *P* < 0.05). Four prey species, water hens, *S. orientalis*, thrushes, and *J. polygonata* did not show statistically significant seasonality (*G*-test, *P* > 0.05), but these frequency occurrences also varied among seasons.

A more detailed picture of seasonality of the diet composition emerges from applying a *PCA* model to the data matrix in Table 2. The first and second principal components of *PCA* explained 53.0% and 31.2% of the total variability, respectively, and the scores of the first and second factors are presented in Table 3. In the score plot of each prey species on factors, the main variables ordering the various species along factor 1 were "autumn-spring", and those ordering the species along factor 2 were "summer-winter", which were sufficient to illustrate the main structure of diet composition among seasons (Fig. 3).

*Rhacophorus owstoni* and *M. ornata* were most frequently eaten in winter. *P. dasymallus*, *Rattus ratuus*, and *T. elegans* were more frequently eaten in winter and spring. *Buergeria japonica*, *S. orientalis*, *J. polygonata*, and *R. supranarina* were most frequently eaten in spring. *Corvus macrorhynchosi*, *Rhabdoblatta* spp., *F. limnocharis*, water hens, and *Eumeces* spp., were more frequently eaten in spring and summer. Ducks were eaten most frequently in autumn. *Diestrammena* spp., egrets, *C. novaeguineae*, and *Turdus* spp., were eaten more frequently in autumn and winter.

## **4. Discussion**

The results of this scat analysis show that the Iriomote cat fed on various types of prey, as observed in earlier studies (Sakaguchi & Ono, 1994; Watanabe et al., 2003). I observed 76 prey items of the cat demonstrating considerable diversity among the dietary studies. In other studies, scats analysed were collected from parts of the island during several years while scats analysed in the present study were collected from the whole island over a long-time period. Thus, a large number of scat contents were analysed, and many differences such as seasonal variation and localities of a variety of prey items could be estimated. Therefore, I believe that the results show general representation of the cat diet in the present study.

The Iriomote cat fed considerably more on avian prey than other animals in the present study although birds are almost always not principal prey among other wild felids (Kruuk, 1982; M. Sunquist & F. Sunquist, 2002). Some other small cats such as *Felis margarita*, *F. silvestris*, *Herpailurus yaguarondi*, *Leptailurus serval*, and *Oncifelis geoffroyi*, occasionally hunt bird prey, but the frequency of these occurrences are much lower than that of the Iriomote cat (M. Sunquist & F. Sunquist, 2002). It is therefore likely that the hunting pattern of the Iriomote cat is the most developed in focusing on bird prey among the cat family.

Of eighteen avian groups which were frequently observed in the prey censuses, thirteen groups were eaten by the cat; others are all arboreal foragers. Sakaguchi & Ono (1994) suggested that the cat may hunt mainly on the ground because all nine bird species found in their analysis were mainly foraging on the ground. I found that the cat occasionally preyed

The frequency occurrences for each season of 19 major prey groups which were frequently found in the scats were calculated, and the seasonal variations were compared among seasons (Table 2). Fifteen groups of the prey items showed significant seasonality (*G*-test, *P* < 0.05). Four prey species, water hens, *S. orientalis*, thrushes, and *J. polygonata* did not show statistically significant seasonality (*G*-test, *P* > 0.05), but these frequency occurrences also

A more detailed picture of seasonality of the diet composition emerges from applying a *PCA* model to the data matrix in Table 2. The first and second principal components of *PCA* explained 53.0% and 31.2% of the total variability, respectively, and the scores of the first and second factors are presented in Table 3. In the score plot of each prey species on factors, the main variables ordering the various species along factor 1 were "autumn-spring", and those ordering the species along factor 2 were "summer-winter", which were sufficient to

*Rhacophorus owstoni* and *M. ornata* were most frequently eaten in winter. *P. dasymallus*, *Rattus ratuus*, and *T. elegans* were more frequently eaten in winter and spring. *Buergeria japonica*, *S. orientalis*, *J. polygonata*, and *R. supranarina* were most frequently eaten in spring. *Corvus macrorhynchosi*, *Rhabdoblatta* spp., *F. limnocharis*, water hens, and *Eumeces* spp., were more frequently eaten in spring and summer. Ducks were eaten most frequently in autumn. *Diestrammena* spp., egrets, *C. novaeguineae*, and *Turdus* spp., were eaten more frequently in

The results of this scat analysis show that the Iriomote cat fed on various types of prey, as observed in earlier studies (Sakaguchi & Ono, 1994; Watanabe et al., 2003). I observed 76 prey items of the cat demonstrating considerable diversity among the dietary studies. In other studies, scats analysed were collected from parts of the island during several years while scats analysed in the present study were collected from the whole island over a long-time period. Thus, a large number of scat contents were analysed, and many differences such as seasonal variation and localities of a variety of prey items could be estimated. Therefore, I believe that the results show general representation of the cat diet

The Iriomote cat fed considerably more on avian prey than other animals in the present study although birds are almost always not principal prey among other wild felids (Kruuk, 1982; M. Sunquist & F. Sunquist, 2002). Some other small cats such as *Felis margarita*, *F. silvestris*, *Herpailurus yaguarondi*, *Leptailurus serval*, and *Oncifelis geoffroyi*, occasionally hunt bird prey, but the frequency of these occurrences are much lower than that of the Iriomote cat (M. Sunquist & F. Sunquist, 2002). It is therefore likely that the hunting pattern of the

Of eighteen avian groups which were frequently observed in the prey censuses, thirteen groups were eaten by the cat; others are all arboreal foragers. Sakaguchi & Ono (1994) suggested that the cat may hunt mainly on the ground because all nine bird species found in their analysis were mainly foraging on the ground. I found that the cat occasionally preyed

Iriomote cat is the most developed in focusing on bird prey among the cat family.

illustrate the main structure of diet composition among seasons (Fig. 3).

varied among seasons.

autumn and winter.

in the present study.

**4. Discussion**

on arboreal species such as *H. amaurotis* and *Parus* spp., suggesting the Iriomote cats arboreal activities. However, prey preferences of the cat for arboreal birds were much lower than those for terrestrial foraging bird species. Thus, I support the prediction of Sakaguchi & Ono (1994) that the cat is a species foraging mainly on the ground, as opposed to in trees.

Species compositions of avifauna as potential prey resources of the cat drastically changed in relation to migrations of birds. This island with such abundant small vertebrates is known as a way station or breeding place for many migrant birds; 191 species belonging to 15 orders, 43 families, and 106 genera are recorded on this island, 83% of which are seasonal migrators while resident bird species occupy at least 17% of the total avifauna on the island (Okinawa Prefectural Education, 1985). In the cat diet, these avian prey items were present at high frequency. Thus, I presumed that such drastic seasonal changes of potential food resources of the cat in relation to migrations of large numbers of birds would strongly influence the feeding habits of the Iriomote cat.

Consequently, bird migrations largely affected the cat diet, particularly during winter by some migrators such as *Turdus* spp., ducks, *Motacilla* spp., and egrets. Most species of resident birds on the island breed during spring and summer (Takano, 1985); many juvenile birds were observed from June to August during the prey censuses. Particularly, *A. phoenicurus* and *C. macrorhynchos* were frequently preyed upon during spring and summer. It is likely that more vulnerable juveniles were frequently eaten during these periods. Although reptiles are principal prey items during spring and summer, the availability of this prey decrease during winter due to their low physiological activity under low temperature (Sakaguchi & Ono, 1994). It is, therefore, likely that the migrations of winter birds largely contribute to supply a deficiency of food resource during winter.

In dietary studies of other *P. bengalensis* populations, the cat diet is monopolized by mammalian prey in a continental habitat (Thailand), bird prey were present at less than 2% of their scats (Rabinowitz, 1990). On an island site, Tsushima Islands, Japan, although mammalian prey are also the most important food in the diet, the cat also preys heavily on birds (41.7% for the frequency of occurrence in the scats: Inoue, 1972). Unfortunately, there is little available information for diets of other wild felids on island sites. However, I could find those of feral domestic cat, *Felis catus*, populations which are widespread all over the world, and they had been introduced to many islands (Fitzgerald & Tuner, 2000). Dietary studies of domestic cats on continents show that mammals are usually the main prey eaten by cats, while birds are much less important than mammals. However, birds are much more important in the diet of domestic cats on islands than on continents. Particularly, on islands where seabirds are recorded in the diet, birds are present on average at 60% of frequency of occurrence in their scats (Fitzgerald & Tuner, 2000). Although small mammals such as rodents or lagomorphs are available on many islands, feral cat populations can persist on islands that lack mammalian prey but are abundant in birds (Kirkpatrick & Rauzon, 1986). Therefore, I suggest that the Iriomote cat can endure on its small island despite a poor mammalian fauna by means of shifting principal prey items to seasonal migrators, particularly during winter. It is during this winter period, that the mating season of the cat takes place(Okamura et al., 2000); home range size and activity of male cats increase (Nakanishi et al., 2005; Schmidt et al., 2003, 2009). Thus, the food requirement of the cat should increase in that time. Therefore, it is likely that winter migrators supply an increment of food requirement for reproduction of the cat.

Ecological Flexibility of the Top Predator in an

*M. ornata*, *B. japonica*, and *Diestrammena* spp., during winter.

same habitats during periods of prey resource scarcity.

movement patterns and prey availability of the cat in the further study.

insular environment of Iriomote Island.

**5. Conclusion**

species.

Island Ecosystem – Food Habit of the Iriomote Cat 479

*japonica* and *M. ornata* are both small species, thus the values for the cat diet are presumably lower than those of larger frogs. Therefore the selectivity of frog species by the cat resulted from the differences of prey values, environments inhabited, and breeding cycles of each

From spring to summer, the availability of many reptiles, frogs, and resident birds are high; thus, the cat feeds on various prey types during the period. Meanwhile, availability of these prey species decreases during winter. Thus, the cat changes principal prey during winter. Additionally, the cat frequently preys on small-sized prey items such as frogs and insects,

Even if prey resources seasonally decreased or occasionally disappeared in habitats of open environment such as on continents, predators would move to search for other habitats encompassing plenty of food. Indeed, home ranges of leopard cats on the continent largely shift depending on wet and dry seasons and its sizes are much larger (Rabinowitz, 1990; Grassman, 2000, 2005) than those of Iriomote cats (Nakanishi et al., 2005; Schmidt et al., 2003). In restricted habitats such as small islands, however, predators have to remain in the

The feeding pattern of leopard cats is presumed to be one of randomly foraging within a wide area with a relatively high abundance of their prey, and these cats prey on encountered animals; that is indicating an opportunistic feeding pattern (Fitzgerald & Tuner, 2000). The results in this study support that Iriomote cats are also opportunistic predators due to their non-selective varied diet representing prey availability with seasonal variations. The Iriomote cat is more likely to opportunistically forage in areas of abundant prey resources, feeding on various prey. However, it is unlikely that cats travel within their habitat and chase encountered volant birds. It is more effective that cats ambush and then attack a bird coming within close reach of the cat; that is using an ambushing feeding pattern. Therefore, the cats may shift their feeding tactics when switching their principal prey items. The movement pattern of the Iriomote cat varies in relation to seasons and local differences of habitats (Nakanishi et al., 2005; Sakaguchi, 1991; Schmidt et al., 2003, 2009). It may also vary in relation to shifting feeding patterns of the cat depending on seasonal difference of principal prey items. These patterns will be more clarified by comparison of

From the above results, I considered that the broad range of the food niche of the Iriomote cat probably resulted from making the best possible use of fauna on the small subtropical island. Furthermore, the cat adapts to the islandwide environment to change principal prey items and feeding patterns in relation to temporal variations of food availability. I suggest that such flexibility of food habits of the Iriomote cat plays an important role for its existence on the small isolated habitat. Most small felids may potentially have such flexible properties in their ecology. However, I believe that it is revealed only in the peculiar fauna of the

The leopard cat, *Prionailurus bengalensis*, is one of most widespread felids and is distributed throughout Asia. The Iriomote cat *Prionailurus bengalensis iriomotensis*, a subspecies of the

In addition, the number of migrant birds on this island largely fluctuated year by year, particularly *Turdus* spp.; the species were rarely encountered in some years while they have been abundant in most years during this decade (Iriomote Wildlife Conservation Center pers. comm.). The incidence of winter migrators may influence survival rate and breeding success of the Iriomote cat.

In the case of the other main prey items of the Iriomote cat, amphibians were the second most frequent prey eaten in the cat diet. The Iriomote cat is also unique among the cat family in feeding on amphibians. For other carnivores, however, numerous mustelids are found to prey upon anurans. Although otters *Lutra lutra*, American mink *Mustela vision*, and badger *Meles meles* sometimes consume a significant quantity of frogs and toads, the occurrences of amphibians in the diet of carnivores remain generally low (Chanin & Linn, 1980; Erlinge, 1969; Webb, 1975; Wise et al., 1981). Exceptionally, polecats *Mustela putorius*  feed heavily on anurans. Anurans occupy about 46% of the total number of prey which is almost the same as that of mammalian prey. However, the predation of anurans is limited only during spring while the availability of anurans is particularly high in relation to their breeding season (Lodé, 1996). In the present study, the Iriomote cat frequently feeds on anurans throughout the year. The abundance of amphibian fauna on the island is the highest so far reported in Old and New world tropics; that is relatively high throughout the year due to different breeding periods of several species (Watanabe et al., 2005). The availability of the frog species most frequently eaten, *F. limnocharis*, is high during spring and summer due to their breeding season (Watanabe et al., 2005). The frogs were mainly eaten during these periods. From autumn to winter, the availability of the frogs drastically decreased and they were not frequently eaten by the cat. During winter, the availability of two other species, *Rh. owstoni* and *M. ornata*, were high and they were mainly eaten during this period. Therefore anurans on the island are available food for the Iriomote cat throughout the year.

There are eight species of the amphibian fauna of Iriomote Island, of which five species were found in the scat contents of the cat. Of the other three species, *R. utsunomiyaorum*, lives chiefly near streams in montane forests (Maeda & Matsui, 1999); this species is rarely found and was not found during these censuses. Although *C. eiffingeri* was frequently observed during the censuses, I found this frog by mainly identifying their calls when made by individuals located on trees, whilst these frogs were rarely found on the ground. This species was not observed on the ground during the prey census in this study. Thus, the result also supports the prediction that the cat mainly hunts animals on the ground. *Rana psaltes* was a ground-dwelling species but the species was not found in the scat samples. It is not clear why the species was absent in the cat diet but it is possible that the density of this species is particularly low compared with those of other anurans in the habitats of the cat, or the identification of this species was not successfully achieved in the scat analysis.

The frogs eaten by the cat, *R. supranarina* and *Rh. Owstoni,* were only selectively preyed upon. For estimation of prey value for each species, a species with large mass is probably higher than a species with a small mass. It is because, from the results estimating body mass of *F. limnocharis* in scat contents of the Iriomote cat, the cat selectively preys on large sized frogs and avoids immature small frogs (Watanabe & Izawa, 2005). *Rana supranarina* is the largest frog species of the amphibian fauna. The size of adult *Rh. owstoni* is almost same as *F. limnocharis* but only breeding adults *Rh. owstoni* were observed during winter. *Buergeria*

In addition, the number of migrant birds on this island largely fluctuated year by year, particularly *Turdus* spp.; the species were rarely encountered in some years while they have been abundant in most years during this decade (Iriomote Wildlife Conservation Center pers. comm.). The incidence of winter migrators may influence survival rate and breeding

In the case of the other main prey items of the Iriomote cat, amphibians were the second most frequent prey eaten in the cat diet. The Iriomote cat is also unique among the cat family in feeding on amphibians. For other carnivores, however, numerous mustelids are found to prey upon anurans. Although otters *Lutra lutra*, American mink *Mustela vision*, and badger *Meles meles* sometimes consume a significant quantity of frogs and toads, the occurrences of amphibians in the diet of carnivores remain generally low (Chanin & Linn, 1980; Erlinge, 1969; Webb, 1975; Wise et al., 1981). Exceptionally, polecats *Mustela putorius*  feed heavily on anurans. Anurans occupy about 46% of the total number of prey which is almost the same as that of mammalian prey. However, the predation of anurans is limited only during spring while the availability of anurans is particularly high in relation to their breeding season (Lodé, 1996). In the present study, the Iriomote cat frequently feeds on anurans throughout the year. The abundance of amphibian fauna on the island is the highest so far reported in Old and New world tropics; that is relatively high throughout the year due to different breeding periods of several species (Watanabe et al., 2005). The availability of the frog species most frequently eaten, *F. limnocharis*, is high during spring and summer due to their breeding season (Watanabe et al., 2005). The frogs were mainly eaten during these periods. From autumn to winter, the availability of the frogs drastically decreased and they were not frequently eaten by the cat. During winter, the availability of two other species, *Rh. owstoni* and *M. ornata*, were high and they were mainly eaten during this period. Therefore anurans on the island are available food for the Iriomote cat

There are eight species of the amphibian fauna of Iriomote Island, of which five species were found in the scat contents of the cat. Of the other three species, *R. utsunomiyaorum*, lives chiefly near streams in montane forests (Maeda & Matsui, 1999); this species is rarely found and was not found during these censuses. Although *C. eiffingeri* was frequently observed during the censuses, I found this frog by mainly identifying their calls when made by individuals located on trees, whilst these frogs were rarely found on the ground. This species was not observed on the ground during the prey census in this study. Thus, the result also supports the prediction that the cat mainly hunts animals on the ground. *Rana psaltes* was a ground-dwelling species but the species was not found in the scat samples. It is not clear why the species was absent in the cat diet but it is possible that the density of this species is particularly low compared with those of other anurans in the habitats of the cat, or

the identification of this species was not successfully achieved in the scat analysis.

The frogs eaten by the cat, *R. supranarina* and *Rh. Owstoni,* were only selectively preyed upon. For estimation of prey value for each species, a species with large mass is probably higher than a species with a small mass. It is because, from the results estimating body mass of *F. limnocharis* in scat contents of the Iriomote cat, the cat selectively preys on large sized frogs and avoids immature small frogs (Watanabe & Izawa, 2005). *Rana supranarina* is the largest frog species of the amphibian fauna. The size of adult *Rh. owstoni* is almost same as *F. limnocharis* but only breeding adults *Rh. owstoni* were observed during winter. *Buergeria*

success of the Iriomote cat.

throughout the year.

*japonica* and *M. ornata* are both small species, thus the values for the cat diet are presumably lower than those of larger frogs. Therefore the selectivity of frog species by the cat resulted from the differences of prey values, environments inhabited, and breeding cycles of each species.

From spring to summer, the availability of many reptiles, frogs, and resident birds are high; thus, the cat feeds on various prey types during the period. Meanwhile, availability of these prey species decreases during winter. Thus, the cat changes principal prey during winter. Additionally, the cat frequently preys on small-sized prey items such as frogs and insects, *M. ornata*, *B. japonica*, and *Diestrammena* spp., during winter.

Even if prey resources seasonally decreased or occasionally disappeared in habitats of open environment such as on continents, predators would move to search for other habitats encompassing plenty of food. Indeed, home ranges of leopard cats on the continent largely shift depending on wet and dry seasons and its sizes are much larger (Rabinowitz, 1990; Grassman, 2000, 2005) than those of Iriomote cats (Nakanishi et al., 2005; Schmidt et al., 2003). In restricted habitats such as small islands, however, predators have to remain in the same habitats during periods of prey resource scarcity.

The feeding pattern of leopard cats is presumed to be one of randomly foraging within a wide area with a relatively high abundance of their prey, and these cats prey on encountered animals; that is indicating an opportunistic feeding pattern (Fitzgerald & Tuner, 2000). The results in this study support that Iriomote cats are also opportunistic predators due to their non-selective varied diet representing prey availability with seasonal variations. The Iriomote cat is more likely to opportunistically forage in areas of abundant prey resources, feeding on various prey. However, it is unlikely that cats travel within their habitat and chase encountered volant birds. It is more effective that cats ambush and then attack a bird coming within close reach of the cat; that is using an ambushing feeding pattern. Therefore, the cats may shift their feeding tactics when switching their principal prey items. The movement pattern of the Iriomote cat varies in relation to seasons and local differences of habitats (Nakanishi et al., 2005; Sakaguchi, 1991; Schmidt et al., 2003, 2009). It may also vary in relation to shifting feeding patterns of the cat depending on seasonal difference of principal prey items. These patterns will be more clarified by comparison of movement patterns and prey availability of the cat in the further study.

From the above results, I considered that the broad range of the food niche of the Iriomote cat probably resulted from making the best possible use of fauna on the small subtropical island. Furthermore, the cat adapts to the islandwide environment to change principal prey items and feeding patterns in relation to temporal variations of food availability. I suggest that such flexibility of food habits of the Iriomote cat plays an important role for its existence on the small isolated habitat. Most small felids may potentially have such flexible properties in their ecology. However, I believe that it is revealed only in the peculiar fauna of the insular environment of Iriomote Island.

## **5. Conclusion**

The leopard cat, *Prionailurus bengalensis*, is one of most widespread felids and is distributed throughout Asia. The Iriomote cat *Prionailurus bengalensis iriomotensis*, a subspecies of the

Ecological Flexibility of the Top Predator in an

Japan (in Japanese)

pp.421-426, ISSN 0001-7051

1939

Vol.29, No.3, pp.12-16, ISSN 0030-1299

978-047-1104-07-0, Chichester, UK

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leopard cat, lives only on Iriomote Island of the Ryukyu Archipelago in southern Japan. Although there are thousands of islands of various sizes within the range of distribution of the species, the Iriomote cat is the only population on such a small island (284 km2). Moreover, on the island, there are no autochthonous terrestrial small mammals such as rodents that are generally the principal prey of wild felids. Thus, it is likely that there are unique characteristics of the ecology of the cat as the top predator in the ecosystem. In the present study, I aim to clarify characteristics of the cat population inhabiting the most limited environment for wild felids.

The cat diet was examined regarding prey preference and seasonal pattern of each prey item by analysing their 947 scat contents collected from various environments throughout the island. I also investigated potential prey availability for the cat using a total length of 242 km of transects conducted over two years.

In the cat diet, 76 prey items were found, this being the most diversified diet in the cat family. Seasonal patterns of 19 principal prey items were examined, which was compared with those of prey availability. Both prey availability and predation varied between seasons. The cat seasonally shifted principal prey items in relation to prey availability. The seasonal patterns of prey availability were chiefly influenced by seasonal migration of birds, by temperature variation for reptiles, by reproductive cycles for insects and by temperature variation and reproductive cycles for amphibians, respectively.

From the above results, I considered that the broad range of the food niche of the Iriomote cat probably resulted from making the best possible use of fauna on the small subtropical island. Furthermore, the cat adapts to the islandwide environment to change principal prey items and feeding patterns in relation to temporal variations of prey availability.

## **6. Acknowledgment**

This study could not have been carried out without the support from numerous people and institutions. I would especially like to acknowledge Profs. M. Izawa, M. Tsuchiya, A. Hagiwara, and Dr. N. Nakanishi, at University of the Ryukyus, and Prof. T. Doi at Nagasaki University, Dr. M. Okamura and Dr. N. Sakaguchi at Ministry of the Environment, Dr. A. Takahashi at the National Institute of Polar Research, for their valuable comments relating to this study. I also thank Mr. M. Dunn at the British Antarctic Survey for the language correction of the manuscript. I am also grateful to the Kumamoto Regional Forestry Office of Forestry Agency and the Iriomote Wildlife Center of Japan Ministry of the Environment (IWCC) for supporting this research. The scat censuses of the Iriomote cat were conducted as a part of endangered species conservation projects administered by the Kumamoto Regional Forestry Office. Field work was carried out using the facility of IWCC. I also thank the members of the Ecology laboratory, Faculty of Science, University of the Ryukyus. I also appreciate the kindness of people at IWCC, and many inhabitants of Iriomote Island, Ms. C. Matsumoto and Mr. M. Matsumoto in particular, during the field work. This study was partially funded by the Inui Memorial Trust for Research on Animal Science, Fujiwara Natural History Foundation, Pro Natura Fundation-Japan, and the 21st Century COE program of University of the Ryukyus.

## **7. References**

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leopard cat, lives only on Iriomote Island of the Ryukyu Archipelago in southern Japan. Although there are thousands of islands of various sizes within the range of distribution of the species, the Iriomote cat is the only population on such a small island (284 km2). Moreover, on the island, there are no autochthonous terrestrial small mammals such as rodents that are generally the principal prey of wild felids. Thus, it is likely that there are unique characteristics of the ecology of the cat as the top predator in the ecosystem. In the present study, I aim to clarify characteristics of the cat population inhabiting the most

The cat diet was examined regarding prey preference and seasonal pattern of each prey item by analysing their 947 scat contents collected from various environments throughout the island. I also investigated potential prey availability for the cat using a total length of 242 km

In the cat diet, 76 prey items were found, this being the most diversified diet in the cat family. Seasonal patterns of 19 principal prey items were examined, which was compared with those of prey availability. Both prey availability and predation varied between seasons. The cat seasonally shifted principal prey items in relation to prey availability. The seasonal patterns of prey availability were chiefly influenced by seasonal migration of birds, by temperature variation for reptiles, by reproductive cycles for insects and by temperature

From the above results, I considered that the broad range of the food niche of the Iriomote cat probably resulted from making the best possible use of fauna on the small subtropical island. Furthermore, the cat adapts to the islandwide environment to change principal prey

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**6. Acknowledgment**

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## *Edited by Mahamane Ali*

The ecosystems present a great diversity worldwide and use various functionalities according to ecologic regions. In this new context of variability and climatic changes, these ecosystems undergo notable modifications amplified by domestic uses of which it was subjected to. Indeed the ecosystems render diverse services to humanity from their composition and structure but the tolerable levels are unknown. The preservation of these ecosystemic services needs a clear understanding of their complexity. The role of research is not only to characterise the ecosystems but also to clearly define the tolerable usage levels. Their characterisation proves to be important not only for the local populations that use it but also for the conservation of biodiversity. Hence, the measurement, management and protection of ecosystems need innovative and diverse methods. For all these reasons, the aim of this book is to bring out a general view on the function of ecosystems, modelling, sampling strategies, invading species, the response of organisms to modifications, the carbon dynamics, the mathematical models and theories that can be applied in diverse conditions.

Diversity of Ecosystems

Diversity of Ecosystems

*Edited by Mahamane Ali*

Photo by AlexeyVis / iStock


**1. Introduction**

Urbanization is known to have substantial impacts on landscapes and ecosystems [1–4], and urban inhabitants are expected to reach 70% of the world population by 2050 [5]. Moreover, the nature of urban development has been changing from a single city model to a group of cities (urban agglomeration) worldwide. Urban heat island (UHI), urbanization, and climate change are increasingly interconnected, resulting in several environmental consequences (such as heat stress, biodiversity loss, fire risk, warming water due to run off, and diminished air quality) at both local and regional levels [2,6–9]. Such UHI related impacts are also called UHI regional impacts (UHIRIP). Generally, UHI research includes data from two major sources: air temperature data that are observed by weather or climate stations and remotely sensed data to observe UHI through land surface temperature. Before the availability of remotely sensed data, UHI was widely observed in the field, with the first scientific observation of UHI in 1833 [10]. Field observations of UHI continue to be a critical source of training and validation data [11,12]. These observations, along with modeling studies, continue to help unravel the factors that are responsible for UHI development, and are providing a basis for the development and application of sustainable adaptation strategies. Communicating scientific knowledge quickly and effectively of UHI and UHIRIP to architects, engineers, scientists, and planners could help inform urban

**Citation:** Shi, H.; Xian, G.; Auch, R.; Gallo, K.; Zhou, Q. Urban Heat Island and Its Regional Impacts Using Remotely Sensed Thermal Data—A Review of Recent Developments and Methodology. *Land* **2021**, *10*, 867. https://doi.org/10.3390/land10080867

Academic Editors: Sara Venafra, Carmine Serio and Guido Masiello

Received: 17 July 2021 Accepted: 11 August 2021 Published: 18 August 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

design and decision making. Remotely sensed data have been used to observe UHI and UHIRIP on environments, ecosystems, human health, and economics in urban and nonurban areas for decades. Remote sensing offers the benefits of long data archives, repeated observations, efficiency, and multiple temporal and spatial resolutions. UHI studies using remotely sensed data have been published for hundreds of cities worldwide [6,7,13–19]. Remotely sensed data provide highly efficient, long-term, and broad-scale information for assessing UHIRIP. However, studies integrating high spatial resolution imagery (e.g., Landsat at 30 × 30 m and ECOSTRESS at 70 × 70 m) from multiple sensors to evaluate UHI and UHIRIP across a time series have been uncommon. Challenges to such studies include image frequency and calibration, cloud contamination, and the need for large storage and high-performance computing capabilities [20,21]. Early generations of broad-scale UHI assessment using remote sensing often poorly represented the spatial and temporal variance in UHI, especially at the urban and non-urban interface. As the resolution of algorithms and satellite imagery improved and interest in UHIRIP grew, researchers sought better representations of UHI. Initially, this took the form of modifications based on surface physical characteristics such as roughness length, albedo, thermal conductivity, and thermal diffusivity [22,23]. Many studies have been conducted to understand the urban thermal climate or the potential for heat island mitigation using this framework of simplified algorithms [24–26]. In more recent efforts, researchers have incorporated more sophisticated parameterization schemes that have included distributions of demography, policies, and behavior of government; ecological variables and ecosystem services; land use and land cover change (LULCC) patterns; and social and economic factors to represent the complicated impacts of UHI [27–36].

Historically, the study of UHI using remote sensing data, often Landsat data, was mainly based on comparing images at two different times using the bitemporal approach [37–39]. Although the bitemporal approach is mathematically simple and does not need large amounts of data, it is less useful than a time series approach that is able to provide a more comprehensive understanding of the complexity of UHI. Most early research [17,40–42] in UHI focused on cities or urban areas, and often ignored the urban and non-urban interface at regional scales. In recent decades, the cost of data storage has dramatically decreased, and we have witnessed an overwhelming increase in computing power and open source software that provide the foundations for time series analysis using higher resolution thermal data from satellite archives. Some studies used Landsat time series to detect historical changes [20,43–46], but few have focused on UHI and its interaction with land use and land cover (LULC) dynamics. A research team at the USGS Earth Resources Observation and Science (EROS) Center recently developed the Land Change Monitoring, Assessment, and Projection (LCMAP) project [47], which is produced with Landsat Analysis Ready Data (ARD) [48] and land surface temperature (LST) data. LCMAP data provide the potential to use Landsat LST data to analyze UHI in urban agglomerations, as well as the urban and non-urban interface at local, regional, and global scales.

This paper reviews remote sensing thermal data sources and the most up-to-date methods used for UHI and UHIRIP investigations. We start by defining UHI, UHII (UHI intensity), regional impacts, urban and non-urban interface, and remotely sensed data sources for LST. We then describe the major distinct approaches that have been used to estimate the magnitude, spatial distribution, intensity, and change pattern of UHIRIP in urban agglomerations and at different urban and non-urban interfaces. Our primary goals in this review are to describe (1) a brief historical summary in the research of UHI and UHIRIP, (2) major thermal data sources and methods used in UHI and UHIRIP research, (3) algorithms used in UHI and UHIRIP analysis, and (4) future research perspective and potential direction. Following the introduction, we discuss the development of UHI and UHIRIP in Section 2; in Section 3, we focus on the application of the remotely sensed thermal datasets in UHI and UHIRIP; we review the algorithms for UHI and UHIRIP in urban and non-urban interface studies based on remotely sensed data in Section 4; in

Section 5, we summarize UHI and UHIRIP based on remotely sensed data; and in Section 6, future research directions are discussed.

### **2. Development of UHI and UHIRIP Analysis**

Most satellite-based investigations of UHIs can be summarized into five main objectives: (1) to examine the spatial features of urban thermal patterns and change dynamics and their relations to urban surface characteristics; (2) to study urban surface energy balances through coupling with urban climate models, including simulation and projection; (3) to study the relations between atmospheric heat islands and surface UHIs through combining coincident remote and ground-based observations; (4) to develop approaches to reduce the magnitude of the UHI and its regional impacts; and (5) to study the UHI effects on ecosystem security at a regional level. Several important reviews, bibliographies, and summaries on UHIRIP using remotely sensed data have been published (see list and descriptions in Table 1). These reviews have concentrated mostly on the various worldwide perspectives of UHI, including the definition of fundamental concepts, summary of methods, applications, exploration of output characteristics, outlines of key research findings, and potential future directions (Tables 2 and 3). The focus of this paper is on the algorithms and methods used in studies employing remote sensing thermal data for UHI and UHIRIP investigation, and future directions in this realm. We summarize (1) the disadvantages of using limited time remotely sensed data for UHI and UHIRIP analysis; (2) the limitations of data shortages due to cloud cover and satellite revisit intervals; (3) the applications of gap filling, data fusion, and deep learning; and (4) the trade-offs between high temporal frequency data (MODIS) and high spatial resolution (Landsat) time series.

**Table 1.** Example of main reviews, bibliographies, and summaries on UHI and UHIRIP using remotely sensed data.

**Table 1.** *Cont.*

**Table 2.** Examples of research publications investigating UHI and UHIRIP using remotely sensed data.

**Table 3.** The temporal frequency and spatial resolution of the main remotely sensed thermal data.


*3.7.1. Purpose of the technique*

The Treatment and Education of Autistic and Communication-Handicapped Children (TEACCH) program is intended to assist children in completing daily tasks by providing instructions that are clear and understandable in an environment that is highly structured and supportive [63]. TEACCH is considered a structured teaching program that recognizes the characteristics commonly associated with autism spectrum disorder, specifically communication problems, preference for visual information, sensory-related difficulties, attention variability, intense interests/impulses, and time management issues [64]. By offering a highly structured teaching environment focused on each child's individual ASD characteristics and the task at hand, learning development can occur. TEACCH is considered to be a multi-disciplinary approach, focused on collaboration between a variety of service providers, including teachers, therapists, family, and community [65].

diagnosed with autistic disorder or pervasive developmental disorder – not otherwise specified over a 2 year period. The group was split evenly into a control group that did not receive TEACCH and an experimental group that received the TEACCH intervention 2 h per week at school and 2 h per week at home. Results for the main outcome indicators of severity of autism, language, and adaptive functioning showed no significant difference between the control group and the experimental group. Results for the secondary outcomes of parental stress and psychopathological comorbidity indicated significant differences between the control group and the experimental group. Both secondary outcomes indicated greater improvement in the experimental group. The authors indicate that the lack of significance in primary outcomes could possibly be attributed to the low intensity of the TEACCH intervention, which is not standard protocol. The positive secondary outcomes indicate potential of the TEACCH program in decreasing parental stress and child

Occupational Therapy's Role in the Treatment of Children with Autism Spectrum Disorders

http://dx.doi.org/10.5772/intechopen.78696

15

With home-based TEACCH being a major component of the program, it is important to determine the efficacy of that particular approach. Weterlin and associates conducted a study on the efficacy of the Home-TEACCHing Program (HTP) on toddlers with ASD [67]. The sample included twenty 2–3 year old children and their parents. Children and their parents were randomly assigned to either the treatment (HTP) group or the waitlist (WL) group. WL group members were informed that they would receive the treatment at the conclusion of a 12 week wait period. This study yielded three major findings: (1) HTP improved children's independent work skills; (2) Parents were able to structure the physical environment to improve child outcomes; (3) Parents improved their effective prompting, including using visual prompts. Although the sample size was small, findings demonstrate support for the

Overall, research to date on effectiveness of the TEACCH program is very encouraging. Therapists use the components of TEACCH to assist children with ASD in learning tasks. Specifically, therapists using this technique will structure the physical environment (including visual cues), and organize the task with explicit directions in order to assist the child in

The Cognitive Orientation to Occupational Performance (CO-OP) is a task-oriented, problemsolving approach that uses cognitive skills to improve occupational performance. It is typically a verbally based approach that emphasizes teaching clients to incorporate self-talk and problem-solving to address difficulty with the execution of various motor skills [69]. According to Missiuna and associates, elements of CO-OP include concepts related to problem-solving, learning theory, motor learning theory, cognitive strategies, client-centered practice, goal setting, and motivation [69]. CO-OP has been observed to be highly individualized, starting with clinician generated verbal guidance, followed by the development of client internal selfdialog, and finally independent application of problem-solving strategies ([70], p. 190).

behavioral/emotional problems.

use of the Home-TEACCHing Program.

*3.8.1. Purpose of the technique*

learning new skills that aid in improved functional outcomes.

**3.8. Cognitive orientation to occupational performance (CO-OP)**


**3. Analysis Model**

Figure 2 shows the configuration and dimensions of the venturi injector; it contains the following seven parts: entrance, exit, contraction section, throat, mixing chamber, diffuser, and suction chamber. Table 1 presents the geometric parameters of the venturi injector.

**Figure 2.** Configuration of the venturi injector.


**Wasim Ullah Khan**

Assistant Professor (Research) Dr. Wasim Ullah Khan received his BE in Chemical Engineering from the University of Engineering and Technology Lahore in 2008. He obtained his MS degree in Chemical Engineering from King Saud University Riyadh, Saudi Arabia, in 2015. He then moved to New Zealand to continue his doctoral degree under the supervision of Dr. Alex Yip in the Energy and Environmental Catalysis Group at the University of Canterbury, New Zealand. He is currently serving as an Assistant Professor (Research) at the Interdisciplinary Research Center for Refining & Advanced Chemicals, Research Institute, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia where his research focuses on the synthesis, characterization, and catalytic properties of bimetallic catalysts for hydrogen production from ammonia decomposition and design and synthesis of transition metal-based catalyst for in situ copolymerization of ethylene with polar monomer.


**9. Ion exchangers of functional thiosemicarbazide, piperazine and tetrazine groups**

Table 1 presents the characteristic of chosen chelating ion exchangers of thiosemicarbazide, piperazine and tetrazine functional groups widely applied in the concentration and removal of platinum group ions [77–80].

**Table 1.** Examples of the chelating ion exchangers of thiosemicarbazide, piperazine and tetrazine functional groups and their characteristic.


**11. Cryopreservation**

The word is derived from two Greek words. i.e., Kryos means frosting while preservation means storage for a long time or increasing half-life in one way or another. Following these techniques cells and tissues are stored at a much lower or frozen temperature either using carbon dioxide at −79 °C or nitrogen gas at −160 °C in the form of vapors in deep freezers. In the c as e of liquid nitrogen, the limit of temperature would be from 170 °C to 197 °C. The technique involves four stages involving freezing, thawing, and re-culturing, etc. [58]. Thus, freezing temperature inactivates the cells and tissues so that it can be preserved for a longer period. Any of the tissues of the plant can be preserved under proper conditions for example meristem, stem, ovules, anther, embryos, endosperm, cells, and leaves, etc. [59].

The process of cryopreservation being followed by regeneration of the whole plant invoke the following steps **Figure 2**;

## **11.1 Isolation of sterile tissue or cell**

Physiological and structural conditions of plant effects ultimately the survival of the plant during cryopreservation. Tissues to be used in preservation must be healthy, small, young, having rich cytoplasm, and highly vacuolated. In either case, callus acts as the best source of tissues as it is more resistant to damage caused by freezing [60]. So, a callus after 1 to 2 weeks of subculturing is selected for the

#### **Figure 2.**

*Schematic flow sheet representation of steps involved in cryopreservation of plant materials in biotechnology for genetic resource(germplasm) conservation of endangered plant species such as golden paintbrush from natural environment to cryobank in form of seeds, tissues, roots, meristem and shoots etc.*

cryopreservation process. But old and black areas should be avoided and organized structures are preferred more.


**Abstract**

In hemodialysis (HD) patients, depression is linked to morbidity, mortality, a worse quality of life, a shorter life expectancy, and even suicidal thoughts. Intradialytic exercise is regarded as a crucial part of the clinical care management of HD patients because it enhances the effectiveness of HD, lowers systemic inflammation, increases exercise tolerance, lowers depressive symptoms, and improves quality of life.

**Keywords:** intradialytic exercise, depression, hemodialysis, quality of life, hemodialysis effectiveness, exercise tolerance, physical activity, Hamilton depression rating scale


*3.1. Curing Characteristics*

The curing characteristics of the mixed compounds are given in Table 2. It is evident that the minimum torque *ML* significantly decreased with an increase in the primary carbon black particle size. This is caused by the decreasing amount of the immobilized rubber chains on the decreasing carbon black surface, as well as the structure. The low aggregate structure and surface area of the N 990 type leads to weak interaction with rubber chains. Moreover, the thermal production process leads to a higher purity of the carbon black surface, with low content of active groups. This fact can result in a lower stiffening effect. However, in the case of the torque *ML*, interactions between rubber chains and carbon black are mainly caused by physical forces, because the property is in an uncured state [25–28].

**Table 2.** Curing characteristics of the studied compounds.

The difference between the maximum (*MH*) and the minimum (*ML*) torques is marked as Δ*M*, which is a parameter demonstrating the degree of chemical crosslinking. The same amount and type of curing system was observed in the compounds; thus, the degree of Δ*M* is supposed to be comparable for all compounds. In reality, the Δ*M* is significantly different. Evidently, the reaction between the rubber and the curing system is one of the factors affecting the crosslinking process [28,29].

The other factor affecting the crosslinking process is the chemical reaction of the rubber with functional groups on the carbon black surface, which differs depending on the carbon black grade. It was found that these functional groups could have either positive or negative effects on the curing characteristics, depending on carbon black type [29]. Although the N 330 type has a higher surface area compared to the N 550 type, its curing level is lower due to the presence of cure-retarding groups [30]. This phenomenon causes various *t*90 values for the compounds in this study.