Investigating the Relationship between Plant Species Composition and Topography in the Tomeyama Landslide: Implications for Environmental Education and Sustainable Management in the Happo-Shirakami Geopark, Japan

Abstract

The Tomeyama landslide in the Happo-Shirakami Geopark, Japan, has interesting and important geomorphological and geoecological characteristics. Understanding these characteristics is crucial for environmental education and sustainable management in the geopark. In this study, we quantified the characteristics of the landslide, including its precise topography and vegetation. We used high-resolution 2.5 m-mesh ALOS World 3D topographic data to define the topography of the landslide. We also surveyed plant species composition and cover in four plots (three on the upper slope and one on the convex lower foot slope), each measuring 20 m × 20 m. Our findings reveal that the landslide is sited on a northwest-facing slope, 250 m below the ridge top, and has a horseshoe-shaped main scarp with a height of 40 m. Two smaller secondary scarps and their corresponding displaced landslide blocks suggest reactivation since the main landslide event. In the upper slope plots, 40–55 plant species were identified, including 14–16 species associated with the Japanese beech forest and 2–5 species related to the Pterocarya rhoifolia forest. In the lower slope plot, 70 plant species were identified, including 14 species from the Japanese beech forest and 11 from the Pterocarya rhoifolia forest. The upper slope plant community belongs to the Japanese beech forest; however, categorizing the lower slope community is challenging, although more Pterocarya rhoifolia forest species are present compared with the upper slope. These results suggest that certain plant species have adapted to the diverse topography created by the landslide. These findings improve the understanding of landslide topography and plant community composition with respect to environmental factors and thereby support effective environmental education and sustainable management in the Happo-Shirakami Geopark.

1. Introduction

The intricate interplay of geological processes, ecosystem dynamics, and anthropogenic activities influences the landscapes that humans inhabit. Of these dynamic interactions, landslides have emerged as captivating phenomena that offer a distinctive lens into the interplay between Earth’s processes and the delicate equilibrium of its ecosystems [1]. For instance, within landslide regions, intricate and diverse terrain features with unique slope configurations, soil compositions, and moisture conditions contrast with those of the surrounding landscape [2,3]. The elaborate terrain features of landslides, which are characterized by intricate undulations and complexities, are thought to facilitate the colonization of diverse forest plant species [4,5,6]. The ecological milieu of landslide areas showcasing these distinct attributes has the potential to function as educational material for environmental instruction, encouraging an appreciation of natural surroundings and conservation consciousness. Moreover, these attributes have implications for the integration of environmental education and sustainable management practices.

Efforts in environmental education related to landslides have focused predominantly on highlighting their geomorphological and geological formation processes [7]. Furthermore, some initiatives have involved the preservation and utilization of the landforms sculpted by landslides or the remnants of structures impacted by such events [8]. Exemplary cases include sites that showcase intricate geological and geomorphic formation processes, such as the establishment of a geological and landslide museum in Civita di Bagnoregio, Italy [9], as well as field-based educational endeavors along the Dorset and eastern Devon coasts in England [10,11] and within the Picos de Europa National Park in Spain [12]. Moreover, sites preserving the effects of human-induced landslides, such as the Vajont landslide in Italy [8], the Chiu-fen-erh-shan landslide following the 1999 Chi-Chi earthquake in Taiwan [13], and the Aratozawa landslide triggered by the 2008 Iwate–Miyagi inland earthquake in Japan [14], together with their associated structures, have been considered instructive examples. However, there are limited cases in which the relationship between plant species composition and terrain characteristics in landslide areas has been incorporated actively into on-site educational approaches.

This study was conducted in the Tomeya landslide, situated in the Happo-Shirakami geopark, Japan (Figure 1a,b). It is worth noting that there is an existing research gap concerning the comprehensive investigation of plant species composition and topography in the study area. The primary objective of the study was to investigate the relationship between plant species composition and the topography of this landslide. In addition, the study considers the implications of the findings for environmental education.

2. Study Area

The Tomeyama landslide is located on a gentle slope of the Shirakami mountains, where 13% of the area has been designated as a Natural World Heritage site. The landslide spans an elevation of approximately 150–250 m (Figure 1c). Determining the timing and the driving factor behind the landslide occurrence is challenging due to the scarcity of historical records in and around the study area. The geology of the Tomeyama landslide comprises a lower layer of Late Miocene to Early Pliocene mudstone and an upper layer of andesite and its associated pyroclastic rock (Figure 1d) [16]. The andesite volcanic event has a history eruptions dating back to 6.6 Ma [17]. Vegetation in the study area consists of a cool-temperate deciduous broad-leaved forest, composed mainly of Siebold’s beech (Fagus crenata) and Pterocarya rhoifolia. The average annual rainfall in Happo town from 1991 to 2020 was 1501.6 mm; the largest monthly total rainfall occurred in July (172.2 mm) and the smallest in February (68.9 mm) [18].

The forest around the Tomeyama landslide has been protected from logging since the Hansei period (1603–1868). The landslide presently functions as a geosite within the Happo-Shirakami Geopark and plays a crucial role in environmental education initiatives. Visitors to the Tomeyama landslide totaled 1668, 1329, and 1415 in 2019, 2020, and 2021, respectively [19].

3. Methods

3.1. Landslide Topography

Landslide topography was interpreted utilizing a CS stereogram derived from a 2.5 m-mesh AW3D digital elevation model (DEM). The CS stereogram was generated using the CSMapMaker plugin in QGIS [20]. This CS stereogram includes two sets of curvature and slope layers (Figure 2). During the generation of the CS stereogram, a color ramp and a 50% transparency were applied to these layers. Results of the CS stereogram were validated in the field.

3.2. Surveys of Plant Species Composition and Cover

Plant species composition and cover were surveyed within square plots measuring 20 m on each side on the upper slope of the displaced landslide block (Plots 1, 2, and 4) and on the lower slope near the toe of the displaced block (Plot 3) of the landslide (Figure 3 and Figure 4). Due to the steep slope at the toe of the landslide, making it unsuitable for the survey, Plot 3 was chosen on the lower slope near the toe of the displaced block. It is worth noting that the vegetation in this area is visually similar to that found on the toe of the landslide. In each plot, 16 sub-plots were separated by 5 m intervals. Field surveys were conducted on 19 and 26 July 2022.

Slope angles are steeper on the lower slope near the toe of the landslide compared with the upper slope. In the upper slope plots, the distribution of slope angles followed a normal distribution, with Plot 1 having a modal value of 20°–25°, whereas Plots 2 and 4 had a modal value of 10°–15° (Figure 5). The mean slope angles in Plots 1, 2, and 4 were 20.0°, 16.5°, and 12.1°, respectively. In Plot 3, near the toe of the landslide, slope angle exhibited a normal distribution with a mode of 25°–30° and a mean slope angle of 25.2°.

All plant species within each sub-plot of the four survey plots were identified and recorded in four layers of vertical structure (herb layer: 0–1.5 m, shrub layer: 1.5–5 m, understory layer: 5–8 m, and canopy layer: >8 m). The plant cover of each layer was estimated by visual assessment of the percentage of the sub-plot covered by each plant species and recorded using a scale of six coverage classes [21]: class 5 (75–100%), class 4 (50–75%), class 3 (25–50%), class 2 (10–25%), class 1 (<10%), and class “+” (for very few individuals accounting for less than 1% of the area) [22]. In cases where the same species appeared in multiple layers, the highest coverage class observed among the layers was assigned.

The classification of the surveyed vegetation into existing communities was determined based on phytosociology. This determination involved referring to the characteristic and differential species of specific plant communities that have been reported in the vicinity of the survey area [23,24].

4. Results and Discussion

4.1. Landslide Topography

The Tomeyama landslide is approximately 350 m wide and 450 m long and has an area of about 0.1 km² (Figure 6). The landslide occurred below an elevation of approximately 250 m, and the displaced block extends in front of a main scarp with a height of 40 m. The main scarp constitutes a horseshoe-shaped cliff facing predominantly northwest. The slope of the landslide generally faces northwest, with the distal end facing the river. The displaced block of the landslide exhibits gentle hilly terrain, with the mid-slope area having a slope angle of approximately 5°–15°. Small valleys are distributed within the displaced block and formed after the occurrence of the landslide. The distal end of the displaced block has convex steep slopes with slope angles exceeding 30°.

On the main scarp, two smaller horseshoe-shaped scarps can be observed (Figure 6a). Below each of these two smaller secondary scarps, small-scale displaced bodies corresponding to each scarp are observed, suggesting the occurrence of secondary landslides associated with the enlargement of the pre-existing main landslide scarp. In addition, the displaced bodies of the secondary landslides have been pushed and accumulated into the back part of the main displaced block, creating concave areas with a maximum width of approximately 50–60 m (Figure 6). The landslide has been mapped previously from aerial photographs [15], which revealed a main landslide scarp and its related displaced block (Figure 1c). Our topographic investigation confirms the main scarp but additionally identifies the horseshoe-shaped smaller scarps, displaced bodies, and concave areas formed by secondary landslides. The topography resulting from the secondary landslide was also observed during the field study.

4.2. Plant Species Composition and Cover Surveys

The numbers of species and plants observed in each layer of vertical structure are shown for Plots 1 to 4 in Figure 7. Only the number of species was recorded for the herb layer, on account of the difficulty in determining the exact number of plants for this layer. The results indicate that, regardless of the survey plot, the number of species was highest in the herb layer, followed by the shrub layer. In addition, the number of plants was highest in the shrub layer, followed by the canopy and understory layers.

Figure 8 presents the results for tree height and circumstance at breast height in the canopy layer for Plots 1 to 4. The mean height of trees in each plot ranged from 16.4 to 17.5 m, with the tallest tree being Fagus crenata, reaching 30 m in Plot 2. The mean circumstance ranged from 1.6 m for Plots 1 to 3 to 1.8 m for Plot 4.

Table 1. Summary of plant species and their coverage classes in Plot 1.

Plant Species	Cover	Plant Species	Cover
Lindera umbellata var. membranacea Moriyama 1,4	5	Pyrola japonica 3	+
Sasa senanensis (Fr. Et Sav.) Rehder 3	5	Ilex crenata Thunb. 3	+
Aucuba japonica var. borealis Miyabe et Kudo 1,4	5	Acer rufinerve 3	+
Acer japonicum Thunb. 1	4	Daphniphyllum macropodum var. humile Rosenthal 1	+
Acanthopanax sciadophylloides Franch. Et Savat. 1	4	Menziesia multiflora Maxim. Var. longicalyx 3	+
Acer palmatum var. matsumurae Makino 3	3	Symplocos chinensis var. leucocarpa f. pilosa Ohwi 3	+
Fagus crenata Blume 1	2	Blechnum niponicum 1	+
Viburnum furcatum Blume 1	2	Disporum smilacinum 1,4	+
Sasa senanensis var. senanensis 3	2	Hydrangea petiolaris Sieb. Et Zucc. 3	+
Euonymus oxyphyllus Miq. Var. oxyphy 3	2	Mitchella undulata 3	+
Schizophragma hydrangeoides Sieb. Et Zucc. 1	1	Huperzia serrata 3	+
Prunus grayana Linn. 3	1	Mognolia obovate Thunb. 1	+
Carex sp. 3	1	Hamamelis japonica var. obtusata Matsumura 1,4	+
Rhus ambigua Lavallee 1	1	Parasenecio delphiniifolius var. delphiniifolius 2,4	+
Cephalotaxus harringtonia var. nana Rehd. 1	1	Rhus trichocarpa Miq. 3	+
Ardisia japonica Blume 3	1	Styras obassia Sieb. Et Zucc. 3	+
Sorbus alnifolia C. Koch 3	1	Styrax japonica Sieb. Et Zucc. 3	+
Fraxinus lanuginosa Koidz. 3	+	Wisteria floribunda DC. 3	+
Acer mono Maxim. 2	+	Callicarpa japonica Thunb. 3	+
		Maianthemum japonicum 3	+

¹ Species related to the Japanese beech forest [23,24]. ² Species related to the Pterocarya rhoifolia forest [23,24]. ³ Neither of the above [23,24]. ⁴ Bold: indicator species [24].

,

Table 2. Summary of plant species and their coverage classes in Plot 2.

Plant Species	Cover	Plant Species	Cover
Lindera umbellata var. membranacea Moriyama 1,4	4	Galium odoratum 3	+
Sasa senanensis (Fr. Et Sav.) Rehder 3	4	Lilium medeoloides var. medeoloides 3	+
Viburnum furcatum Blume 1	4	Actinidia argute Planch. 3	+
Viburnum dilatatum Thunb. 3	3	Acanthopanax sciadophylloides Franch. Et Savat. 1	+
Aucuba japonica var. borealis Miyabe et Kudo 1,4	3	Smilax china Linn. 3	+
Maianthemum dilatatum 3	3	Blechnum niponicum 1	+
Acer japonicum Thunb. 1	3	Euonymus oxyphyllus Miq. Var. oxyphy 3	+
Fagus crenata Blume 1	2	Mitchella undulata 3	+
Schizophragma hydrangeoides Sieb. Et Zucc. 1	2	Skimmia japonica var. intermedia f. repens Hara 1	+
Menziesia multiflora Maxim. Var. longicalyx 3	2	Tripterospermum japonicum var. japonicum 3	+
Carex sp. 3	2	Panax japonicus var. japonicus 2	+
Hydrangea petiolaris Sieb. Et Zucc. 3	2	Viola rostrata 3	+
Tripetaleia paniculata Sieb. Et Zucc. 3	2	Sorbus commixta Hedl. 1	+
Acer rufinerve 3	1	Hydrangea paniculata Sieb. 3	+
Prunus grayana Linn. 3	1	Cephalotaxus harringtonia var. nana Rehd. 1	+
Daphniphyllum macropodum var. humile Rosenthal 1	1	Phryma leptostachya subsp. Asiatica var. asiatica 3	+
Calanthe discolor var. discolor 3	1	Leucothoe grayana Maxim. 3	+
Disporum smilacinum 1,4	1	Ilex leucoclada Makino 1	+
Rhus ambigua Lavallee 1	1	Wisteria floribunda DC. 3	+
Ilex crenata var. paludosa Hara 3	1	Solidago virgaurea subsp. Leiocarpa var. leiocarpa 3	+
Callicarpa japonica Thunb. 3	1	Polygonatum lasianthum Maxim. 3	+
Rhus trichocarpa Miq. 3	1	Parasenecio delphiniifolius var. delphiniifolius 2,4	+
Solidago virgaurea subsp. Asiatica var. asiatica 3	+	Athyrium vidalii 3	+
Fraxinus lanuginosa Koidz. 3	+	Rhododendron kaempferi Planch. 3	+
Acer mono Maxim. 2	+	Acer palmatum var. matsumurae Makino 3	+
Abelia spathulata var. stenophylla 1	+	Prunus sargentii Rehder 3	+
Quercus crispula Blume 1	+	Styras obassia Sieb. Et Zucc. 3	+
Menziesia multiflora Maxim. 3	+	Clethra barbinervis Sieb. Et Zucc. 3	+

¹ Species related to the Japanese beech forest [23,24]. ² Species related to the Pterocarya rhoifolia forest [23,24]. ³ Neither of the above [23,24]. ⁴ Bold: indicator species [24].

,

Table 3. Summary of plant species and their coverage classes in Plot 3.

Plant Species	Cover	Plant Species	Cover
Sasa senanensis (Fr. Et Sav.) Rehder 3	4	Acanthopanax sciadophylloides Franch. Et Savat. 1	+
Carex sp. 3	4	Euonymus alatus var. alatus f. striatus 3	+
Hydrangea petiolaris Sieb. Et Zucc. 3	4	Polystichum retrosopaleaceum 2	+
Acer japonicum Thunb. 1	4	Prunus ssiori Fr. Schm. 3	+
Viburnum furcatum Blume 1	3	Blechnum niponicum 1	+
Aesculus turbinata Blume 2	3	Viola vaginata 2,4	+
Rubus buergeri 3	3	Osmunda japonica	+
Dryopteris sabaei 1	3	Smilax nipponica	+
Dryopteris crassirhizoma 2	2	Disporum smilacinum 1,4	+
Athyrium clivicola 3	2	Paris tetraphylla var. tetraphylla 1	+
Rubus crataegifolius 3	2	Rhus ambigua Lavallee 1	+
Aucuba japonica var. borealis Miyabe et Kudo 1,4	2	Viola verecunda var. verecunda 3	+
Arachniodes borealis 3	2	Huperzia serrata 3	+
Diplazium sibiricum var. glabrum 3	2	Ulmus pumila Linn. 3	+
Lindera umbellata var. membranacea Moriyama 1,4	1	Adenocaulon himalaicum 3	+
Viburnum dilatatum Thunb. 3	1	Hydrangea paniculata Sieb. 3	+
Polystichum tripteron 2	1	Styras obassia Sieb. Et Zucc. 3	+
Sambucus chinensis var. chinensis 3	1	Chloranthus quadrifolius 3	+
Panax japonicus var. japonicus 2	1	Ilex leucoclada Makino 1	+
Cephalotaxus harringtonia var. nana Rehd. 1	1	Wisteria floribunda DC. 3	+
Oxalis griffithii var. griffithii 3	1	Fagus crenata Blume 1	+
Solidago virgaurea subsp. Asiatica var. asiatica 3	+	Athyrium yokoscense var. yokoscense 3	+
Sorbus alnifolia C. Koch 3	+	Disporum sessile var. sessile 3	+
Acer mono Maxim. 2	+	Maianthemum dilatatum 3	+
Asarum sieboldii 3	+	Cornus controversa Hemsley 2	+
Acer rufinerve 3	+	Quercus crispula Blume 1	+
Elatostema japonicum var. majus 2,4	+	Persicaria thunbergii var. thunbergii 3	+
Hydrangea serrata var. megacarpa H. Ohba 2	+	Polygonatum lasianthum Maxim. 3	+
Trillium apetalon 3	+	Dryopteris monticola 2,4	+
Platanthera sachalinensis 3	+	Ardisia japonica Blume 3	+
Prunus sargentii Rehder 3	+	Athyrium vidalii 3	+
Polystichum microchlamys var. microchlamys 3	+	Acer palmatum var. matsumurae Makino 3	+
Coptis japonica var. anemonifolia 3	+	Prunus grayana Linn. 3	+
Clerodendrum trichotomum Thunb. 3	+	Elliottia paniculata (Siebold et Zucc.) Hook.f. 3	+
Onoclea sensibilis var. interrupta 3	+	Clethra barbinervis Sieb. Et Zucc. 3	+

¹ Species related to the Japanese beech forest [23,24]. ² Species related to the Pterocarya rhoifolia forest [23,24]. ³ Neither of the above [23,24]. ⁴ Bold: indicator species [24].

and

Table 4. Summary of plant species and their coverage classes in Plot 4.

Plant Species	Cover	Plant Species	Cover
Sasa senanensis (Fr. Et Sav.) Rehder 3	5	Daphniphyllum macropodum var. humile Rosenthal 1	+
Aucuba japonica var. borealis Miyabe et Kudo 1,4	4	Calanthe sp. 3	+
Fagus crenata Blume  1	4	Betula maximowicziana Rege  3	+
Viburnum furcatum Blume  1	3	Viburnum dilatatum Thunb. 3	+
Carex sp. 3	2	Carpinus cordata var. cordata 3	+
Skimmia japonica var. intermedia f. repens Hara 1	2	Blechnum niponicum  1	+
Stegnogramma pozoi subsp. Mollissima 3	2	Viola vaginata 2,4	+
Schizophragma hydrangeoides Sieb. Et Zucc.  1	1	Smilax nipponica 3	+
Prunus grayana Linn. 3	1	Elliottia paniculata (Siebold et Zucc.) Hook.f.  3	+
Lindera umbellata var. membranacea Moriyama 1,4	1	Euonymus oxyphyllus Miq. Var. oxyphy 3	+
Disporum smilacinum 1,4	1	Aesculus turbinata Blume  2	+
Rhus ambigua Lavallee  1	1	Panax japonicus var. japonicus 2	+
Hydrangea petiolaris Sieb. Et Zucc. 3	1	Astilbe odontophylla var. odontophylla 3	+
Cephalotaxus harringtonia var. nana Rehd. 1	1	Calanthe reflexa 3	+
Maianthemum japonicum 3	1	Hydrangea paniculata Sieb. 3	+
Fraxinus lanuginosa Koidz. 3	+	Ilex crenata var. paludosa Hara 3	+
Meliosma myriantha 3	+	Wisteria floribunda DC. 3	+
Acer mono Maxim.  2	+	Maianthemum dilatatum 3	+
Abelia spathulata var. stenophylla 1	+	Dryopteris sabaei  1	+
Asarum sieboldii 3	+	Acanthopanax sciadophylloides Franch. Et Savat.  1	+
Quercus crispula Blume  1	+	Acer japonicum Thunb.  1	+
Hydrangea serrata var. megacarpa H. Ohba 3	+	Parasenecio delphiniifolius var. delphiniifolius 2,4	+
		Rhododendron kaempferi Planch. 3	+

¹ Species related to the Japanese beech forest [23,24]. ² Species related to the Pterocarya rhoifolia forest [23,24]. ³ Neither of the above [23,24]. ⁴ Bold: indicator species [24].

provide summaries of the plant species composition and coverage classes for the upper slope of the displaced block (Plots 1, 2, and 4) and the lower slope near the toe of the displaced block (Plot 3) of the Tomeyama landslide.

In Plots 1, 2, and 4 on the gentle upper slope, totals of 39, 56, and 45 plant species were observed, respectively. Of these, 14 to 16 species were identified as character and differential species of Japanese beech forest, accounting for nearly half of the species in the herb layer. Moreover, character species strongly associated with this forest community, such as Lindera umbellata var. membranacea Moriyama, Aucuba japonica var. borealis Miyabe et Kudo, Disporum smilacinum, and Hamamelis japonica var. obtusata Matsumura were present with a higher coverage class. In contrast, only 2–5 species were identified as character and differential species of Pterocarya rhoifolia forest.

On the lower slope near the toe of the landslide (Plot 3), a total of 70 plant species were identified. Of these, 14 species were recognized as character and differential species of Japanese beech forest. The percentages of plant cover of the identified character species of this forest community, including Lindera umbellata var. membranacea Moriyama, Aucuba japonica var. borealis Miyabe et Kudo, and Disporum smilacinum, were low, with the Aucuba japonica var. borealis Miyabe et Kudo falling in class 2, Lindera umbellata var. membranacea Moriyama in class 1, and Disporum smilacinum in class “+” in the coverage class system used in this study. In contrast, 11 species were identified as character and differential species of Pterocarya rhoifolia forest. The percentages of plant cover of the identified character species of this forest community, including Elatostema japonicum var. majus, Viola vaginata, and Dryopteris monticola, were low, falling in class “+”.

On the basis of the presented results, it is concluded that the vegetation observed in the survey plots on the gentle upper slope belongs to the Japanese beech forest (Figure 9). Determining the community to which the vegetation on the lower slope near the toe of the landslide belongs is challenging, although a greater number of species related to the Pterocarya rhoifolia forest were found in the plot on the lower slope compared with the plots on the upper slope. Plant community composition differences were observed between the upper and lower slopes of the landslide.

Previous studies have explored the relationship between plant community composition and the geomorphic environment of the Shirakami mountains. Mishima et al. [4] conducted surveys within a landslide area located on the eastern side of the Shirakami mountains, including evaluations of vegetation, subsoil structure, and soil erosion levels. They recorded the presence of Japanese beech forest on the arid upper slope of the landslide, where the soil layer is minimal. In contrast, Pterocarya rhoifolia forest displayed a preference for the moister conditions on the lower slope. Comparable observations have been reported by Tsou et al. [25] for a landslide area on the western side of the Shirakami mountains. Our results reveal similarities with previous studies. It is worth noting that the Japanese beech forest represents the climatic climax forest of the northern Japan Sea region, whereas the Pterocarya rhoifolia forest is the most widely distributed community within the topographic climax forest of the Shirakami mountains [26].

In this study, we investigated the relationship between the present composition of plant communities and topography of the Tomeyama landslide. However, it is essential to acknowledge that plant species composition is also influenced by environmental variables such as aspect, soil porosity, and saturation moisture content, among others [27], which could be the focus of future studies. In addition, the present plant composition and distribution of plant communities could also be influenced by the timescale of post-landslide geomorphic evolution, the process of vegetation succession, and the pace of these transitions [1,28,29]. The present plant composition and distribution of plant communities is likely an outcome of the interplay between these dynamic temporal aspects, which should be investigated in a future study.

4.3. Enhancing Enviromental Education and Sustainable Management

With the aim of enhancing environmental education and sustainable management, we generated a trifold brochure (Figure 10 and Figure 11) to offer the general public insights into the natural environment of the Tomeyama landslide. This content is centered on the relationship between plant species composition and topography of the landslide area. Figure 10 presents the front side of the brochure, which provides general details about the Tomeyama landslide. Figure 11 presents the back side of the brochure, which summarizes the information from Section 4.1 and Section 4.2 of this paper. Guides who introduce visitors to the Tomeyama area are expected to utilize the brochure, making it also valuable for environmental education in schools and local communities. As noted by Koizumi and Chakraborty [30], incorporating environmental education regarding the local geoecological system is crucial for sustainable management, which should be based on knowledge of the natural environment. As a result, the findings of our study make a significant contribution to environmental education and sustainable management.

5. Conclusions

This study focused on enhancing environmental education and sustainable management by measuring the relationship between the plant species composition and the topography of the Tomeyama landslide in the Happo-Shirakami Geopark, Japan. Topographic analysis shows that the landslide occupies a relatively compact space of approximately 0.1 km². This landslide originated from a large-scale primary movement and subsequently underwent reactivation, particularly along its main scarp, producing secondary scarps and displaced bodies. Our study included thorough surveys of plant species composition and cover across four plots, each measuring 20 m × 20 m: three on the upper slope and one on the convex lower foot slope. Results revealed rich plant diversity. On the upper slope, 40–55 plant species were identified, with 14–16 species related to the Japanese beech forest but only 2–5 species related to the Pterocarya rhoifolia forest. The lower slope plot contained 70 species, including 14 from the Japanese beech forest and 11 from the Pterocarya rhoifolia forest. Although categorizing the plant community of the lower slope proved challenging, there was a higher representation of Pterocarya rhoifolia forest species compared with the upper slope. These results indicate that specific plant species have adapted to the varying topography induced by the landslide. We have generated a trifold brochure to enhance environmental education and sustainable management by disseminating the information obtained in this study. This brochure will be used by Happo-Shirakami Geopark guides and for environmental education in schools and local communities.