◎ Lin Jianzheng
Recently, there was a discussion on the conservation of straw owls around Nanke Phase 4, and Shenkengzi Farm, located on the south side of the project area, suddenly received great attention. This land is adjacent to the fourth phase of Nanke. If it can be jointly planned with the grasslands, ecological corridors and surrounding farmland in the park in the future, it will have the opportunity to form a large-scale and interconnected grass owl habitat, and further develop into an important ecological conservation space in the Sharon area.
This article attempts to put forward the preliminary concept of "Shenkengzi Grass Owl Prairie", hoping to think of Shenkengzi Farm as a flagship base for grass owl restoration. This is a preliminary planning proposal. In the future, it should still be based on a complete ecological survey and gradually deepened through expert research, local participation and long-term monitoring to find a habitat creation method suitable for this land.
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The author proposed the preliminary concept of "Shenkengzi Grass Owl Prairie", hoping to think of Shenkengzi Farm as a flagship base for grass owl restoration. (Taken from Lin Jianzheng’s Facebook) From grassland to sparse forest grassland
During the discussion, someone raised a question that deserves attention: In order to create the grassy environment needed by the Grass Owl, should all the original trees be removed in order to conserve a single species? Grass owls do prefer open grassy environments, and large, continuous and stable grasslands should still be the core of habitat creation. From the perspective of the overall ecosystem, conservation work can also further consider how to properly configure grasslands, shrubs, and trees so that grass owls and other species can have suitable living spaces.
There are many different types of transitional ecosystems between forests and completely open grasslands. Among them, "savannah or savannah" provides a concept worthy of reference. Typical sparse forest grasslands are widely distributed in Africa, Australia, South America and parts of Asia. They are an ecosystem composed of herbaceous plants and scattered trees. Its most important feature is that trees keep a certain distance from each other, the tree crown does not form a closed forest canopy, and sunlight can still fully reach the ground, allowing herbaceous plants to continue to grow. From a landscape perspective, it is a prairie with trees; from an ecological perspective, it is a composite habitat formed by herbs, shrubs and trees.
Typical sparse forest grasslands are widely distributed in Africa, Australia, South America and parts of Asia. They are an ecosystem composed of herbaceous plants and scattered trees. (Taken from Wikipedia) Typical tropical sparse grasslands often have distinct dry and wet seasons, and vegetation is affected by rainfall, drought, herbivores, and soil conditions. The climate, plant species and land use history of southwestern Taiwan are different from the typical Savanna in Africa or Australia. Naturally, Shenkengzi Farm is not suitable for directly replicating foreign sparse forests and grasslands. What is really worth learning from is the spatial structure of "mainly grassland, mosaic of sparse forest" and the ecological principle that vegetation of different heights and densities jointly form diverse habitats.
The important value of this spatial structure is to increase the heterogeneity of the environment. A completely homogeneous grassland mainly provides a grassy environment; if some of the original trees, shrubs and forest edges are appropriately retained, the entire environment may form vertical structures of different heights such as herbaceous layer, shrub layer and sparse forest layer; in the horizontal direction, different micro-habitats such as tall grass, low grass, shrubs, isolated trees, small tree groups and water bodies can also be formed.
Specifically, different spaces can be utilized by different species. Large areas of tall grass can provide an environment for grass owls to roost, breed and forage during the day; lower grasslands and partially bare land can provide opportunities for insects, reptiles and ground-dwelling birds to move; shrubs and forest edges can provide small birds with hiding, nesting and foraging; scattered trees can become places for other birds to rest and observe prey. Insects, rodents and other small animals in the grassland also constitute food sources for higher-order predators. As plants, insects, small mammals, reptiles and birds gradually establish relationships with each other, the perspective of conservation can be expanded from one species to a complete food web and ecosystem.
The land memory of sugarcane, field mice and meadowlarks
There is another aspect worth incorporating into the habitat creation of Shenkengzi Farm, which is Sharon’s past agricultural landscape and local memory. Sharon Farm used to be an important sugarcane raw material area for Taiwan Sugar, and its large sugarcane fields were one of the most representative landscapes of this land. The dense sugarcane fields also provide an environment for rodents to hide and forage. The older generation of residents are no strangers to voles. In the past, some people even captured voles, commonly known as "mountain and river meat", which has become a special memory of local life.
From an ecological perspective, this history also provides another clue to understanding the relationship between the Grass Owl and Sharon. Grass owls use small mammals such as rats as an important food source, and rats use grasslands, farmland and other vegetation environments to survive. In this food chain, herbs and crops provide basic productivity. Rats act as primary consumers and are important prey for grass owls, which occupy a higher-level prey position. In the past, Sharon's sugar cane fields, voles, and grass owls can be understood as part of the agricultural landscape food web from an ecological perspective.
The Grass Owl is an endangered first-level protected wild bird in Taiwan and relies on rats and other small mammals as its important food source. (File photo, provided by Tainan Bird Club) In the future, when building the "Shenkengzi Grass Owl Prairie", we can consider retaining or planting small areas of sugar cane in appropriate locations without affecting the core grass owl habitat, so that it can become an agricultural landscape mosaic in the grassland. The purpose of these sugar canes is not to restore the past large-area, single-crop agriculture, nor to deliberately increase the rodent population, but to allow sugar cane to become part of the history of the Sharon land, while increasing the diversity of the habitat structure and food web. If managed with low pesticides, low chemical fertilizers or even friendly farming methods, insects, rodents and other small animals can naturally use these spaces, and predators such as grass owls and black-winged kites can participate in population regulation.
In this way, sugar cane has a double meaning. On the one hand, it preserves the local texture of Sharon Farm that was once covered with sugar cane fields, so that when people in the future walk into the Grass Owl Prairie, they can still understand the history of this land from a small sugar cane field; on the other hand, it can also become a part of the overall mosaic habitat, reestablishing the relationship between the agricultural landscape and the natural ecology. In the future, it can even be combined with environmental education to present the "sugar cane-vole-grass owl" food chain in appropriate areas to illustrate how agriculture, biology and human activities jointly shape Sharon's landscape over the long term.
Create multi-layered habitat gradients
Farm planning can be combined with environmental education to present the "sugar cane - field mouse - grass owl" food chain in appropriate areas. (Taken from Lin Jianzheng’s Facebook) Such a concept does not conflict with straw owl conservation. Existing research shows that the meadowlark is highly dependent on the grassy environment and will avoid relatively closed forests. Therefore, if Shenkengzi Farm takes the conservation of the meadowlark as its main goal, it must still maintain a sufficient, continuous and open grassy core area. The concept of sparse forest grassland should not be understood as planting trees evenly across the entire grassland, nor should it be simply defined as a number of trees per hectare and then evenly distributed among them. What really needs attention is the degree of canopy cover, the position of trees, the continuity of grassland, and the spatial relationship between different vegetation.
In other words, Shenkengzi Farm can consider establishing a set of habitat gradients from the inside out in the future: maintain a large continuous grassy environment in the core area, which serves as the main activity, breeding and foraging space for grass owls; gradually add shrubs and scattered trees to the periphery of the core area to form a sparse forest grassland; retain a small area of sugar cane and other agricultural landscapes with local historical significance in appropriate locations, and then connect to existing woods, windbreaks, ecological corridors, waters or surrounding farmland. In this way, a diverse space of "core grassland area-sparse forest grassland area-agricultural landscape mosaic area-shrub and forest edge area-small forest area" can be formed, taking into account the needs of grass owls for open grassland and the use of different habitats by other species.
Existing trees should also be treated with a more careful approach. Native large trees and existing tree groups with ecological, landscape or historical value can be appropriately retained after investigation; invasive alien species or woody plants that have encroached on important grass habitats can be removed or controlled based on the results of ecological surveys. Trees can be given priority to be retained or arranged at the periphery of the grass core area, roads, water systems, and site boundaries. Through spatial design, "retaining trees" and "creating grassland" can be reasonably configured to avoid falling into the simplified choice of retaining all or removing all.
From grass owls to multi-species symbiosis
The farm then connects to the surrounding farmland to form a diversified space. (File photo) More importantly, Shenkengzi Farm can regard the meadow owl as a representative flagship species and promote the restoration of the grassland ecosystem of the entire southwest plain through its conservation. Grass owls need large areas of grassland, which support insects, rodents, reptiles and other grassland birds; sparse forests and shrubs can provide habitat for other birds and small animals. Ring-necked pheasants, black-winged kites, great crested vultures and other birds that roam the Sharon area can also find suitable ecological niches in different habitat environments.
This also allows the idea of "Shenkengzi Owl Prairie" to move forward. In the future, if we combine the grasslands, ecological corridors, and deep pit farms on the south side of the Nanke Phase IV Park, as well as appropriate conservation and ecological compensation spaces outside the area, we can gradually form a multi-species ecological network with a large continuous grassland as the core, sparse forests, shrubs, forest edges, waters, farmland, and a small amount of sugarcane landscape. Connecting different habitats also helps reduce the impact of habitat fragmentation.
This kind of planning also echoes the concentric circles of species in the "two concentric circles". Starting from the grass owl, we gradually expanded to other birds, mammals, reptiles, insects and native plants; from the habitat needs of one species, we further considered the integrity of the entire ecosystem. Even voles, which were regarded by farmers as agricultural pests in the past, have their own ecological place when they return to the natural food web. What ecological conservation wants to maintain is the long-term dynamic relationship between producers, consumers and predators.
If Shenkengzi Farm can be planned in this direction, it can become a feature of the fourth phase of Nanke's ecological conservation, and also have the opportunity to gradually develop into a flagship base for straw owl habitat restoration, research monitoring and environmental education. An ecosystem formed through scientific investigation, habitat design and long-term management can be established around the industrial park and connected with the ecological spaces inside and outside the park. The sugar cane fields of the past, the grass owls of today, and the sparse forests and grasslands of the future can form a historical and ecological connection on the same piece of land.
Conclusion
Based on recent initiatives by community residents and environmental groups on the Shenkengzi Grass Owl habitat, the "Shenkengzi Grass Owl Prairie" can be further developed into a flagship base for the restoration of the Grass Owl: with a large continuous grassland as the core, moderately integrated into sparse forests, farmland and waters, the memory of the land can be recovered from the sugar cane fields, and living space can be preserved for different species. Starting from the grass owl and moving towards multi-species symbiosis, Shenkengzi becomes a new starting point for Sharon's ecological restoration.
Recovering the memory of the land from the sugarcane fields also preserves living space for different species. (File photo) (The author is the Secretary-General of the Salon Ecological Science City Promotion Association in Quy Nhon District)
