彰化縣福興鄉牧草地昆蟲資源調查

Insect Diversity in Pasture of Fuxing Township, Changhua City

林宗岐(Chung-Chi Lin) ； 施彥仲(Yen-Chung Shih)

《臺中區農業改良場特刊》 144號 (2021/09) Pp. 78-101

摘要

彰化縣福興鄉近年因酪農業發達，牧草需求逐年增加，因此附近地區的廢耕農地開始出租酪農或農會轉作牧草，因牧草多採粗放管理且未使用農藥，鑲嵌於慣行田區之間，有機會提供鄰近農田多樣的生態功能。在2020年6月到2020年10月於5個牧草地調查樣區進行4次調查，調查樣區內將再設置3個調查樣點。對於牧草調查樣區中土棲落葉層與作物層5種牧草地標準化昆蟲調查方法，分為地面掉落式陷阱法、落葉袋採集法、馬氏網誘集法、掃網法及黃色黏紙法。調查結果定量採集中記錄到有6綱、17目、106科，共14,645隻無脊椎動物個體，其中昆蟲綱（Insecta）共採獲13,983隻個體，隸屬於11目、96科，以雙翅目（Diptera）為最多的科級佔27.8%，其次為膜翅目（Hymenoptera）（20.6%）再來是鞘翅目（Coleoptera）（19.7%）。其中個體數量（individuals）最多的是中性物種的雙翅目搖蚊科（Chironomidae），其次是中性物種的膜翅目蟻科（Formicidae），再來是刺吸式草食者半翅目葉蟬科（Cicadellidae）。調查結果也發現作物層的物種占總物種數84.6%，而土棲地物種數佔47.9%，表示福興牧草地昆蟲組成結構上物種多以作物層為主，土棲落葉層昆蟲較少。各季節福興鄉牧草地昆蟲相之生物多樣性變動現象，科級的數量6月（晚春／一期稻作收穫）最多，而8月（夏／二期稻作插秧）則最少；但個體數上則呈現相反的現象8月最多，而6月（晚春／一期稻作收穫）最少。而昆蟲個體數和雨量之間可以發現高度相關，其他環境因子濕度與溫度都與種類、數量較無關聯性。生態功能群結果顯示亦較豐富的中性物種與數量，植食者中數量最多的是禾本科刺吸者，也比較明顯有聚集性發生現象，且在稻作收穫的時期6月（晚春）在牧草地中禾本科刺吸者會明顯增加，禾本科咀嚼者則在9月（秋／二期稻作生長）時期數量與比例均最高。此外，代表害蟲天敵的掠食者與擬寄生者則4個季節的數量數較為一致。

關鍵字

牧草地（Grassland） ； 昆蟲相（Insect fauna） ； 生物多樣性（Biodiversity） ； 生態功能群（Ecological functional group）

並列摘要

In Fuxing Township, Changhua City, the demand for pasture has increased year by year due to the development of daily farming in recent years. Therefore, abandoned farmland in nearby areas has begun to rent out daily farming or farmers' association turn over land to pasture production. Since pasture usually employs extensive management and managed without the use of pesticide, plus embedded in conventional farming sites, there is an opportunity for pasture to provide diverse ecological functions to the neighboring farmland. A total of four surveys were conducted between June 2020 and October 2020, and three sampling points were set up at each of the study sites. For both soil-dwelling deciduous layer and crop layer at grassland study sites, five different standardized insect survey methods were applied, including: pitfall trapping, winkler extraction, malaise trapping, sweep netting technique and yellow sticky trapping. From the quantitative collection, a total of 14,645 invertebrate individuals belonging to 6 classes and 17 orders and 106 families were recorded; under invertebrate, a total of 13,983 insect individuals belonging to 11 orders and 96 families were identified. Among class Insecta, the most dominant insect order in terms of number of families was Diptera (27.8%), followed by Hymenoptera (20.6%) and Coleoptera (19.7%). In terms of number of individuals, the most abundant species was neutral species from Chironomidae, followed by neutral species from Formicidae and piercing-sucking herbivore, Cicadellidae. The survey results also showed that insect species in the crop layer accounted for 84.6% of the total species found within crop layer, while insect species in the soil habitat accounted for 47.9% of the total species found within soil habitat. This indicates that insect composition of the Fuxing pasture is mostly concentrate in crop layer, whereas fewer insect species are exist in the soil-dwelling deciduous layer. Regarding seasonal changes of insect biodiversity in pasture of Fuxing Township, number of families was highest in June (late spring/first-stage rice harvesting) while lowest in August (summer/second-stage rice transplanting). However, in terms of number of individuals, it showed the opposite trend compared with number of families, where the number of individuals was highest in August while lowest in June (late spring/ first-stage rice harvesting). There is a high degree of correlation between the number of insect individuals and rainfall, while other environmental factors such as relative humidity and temperature are not related to the type and numerical quantity of insects. The results of ecological functional groups demonstrated the relatively abundant of neutral species. Among the herbivores, the most abundant group was piercing-sucking insects of Gramineae which tend to showing aggregation phenomenon. Moreover, the number of piercing-sucking insects of Gramineae at pasture increased significantly during rice harvesting period in June (late spring), while both the number and proportion of chewing insects of Gramineae were highest during September (autumn/ second-stage rice growth). In addition, the numbers of predators and parasitoids (i.e., natural enemies of pest) remain relatively consistent throughout the four seasons.