生境数量和生境质量以及气象因子对成都市粪食性金龟物种多样性的影响

The Effects of Habitat Amount,Habitat Quality and Meteorological Factors on the Species Diversity of Dung Beetles in Chengdu

城市化是最具破坏性的土地利用形式之一,其带来的环境变化常导致生物多样性下降。探究环境因子(生境数量、生境质量、气象因子)对环境指示生物粪食性金龟物种多样性的影响对城市生物多样性保护具有重要意义。于2021年7月和9月在成都市不同城市化梯度(城区、近郊、远郊)内选取3种生境类型(林地、灌丛、草地)共18个样地,采用诱罐法采集粪食性金龟。结果表明,1)共采集粪食性金龟5属8种1149头,隶属于同一行为类型(直接掘洞型),且多为小体型(体长<13.0 mm)。嗡蜣螂属(Onthophagus)是研究区域的优势属(4种,1066头),巴氏驼嗡蜣螂(Onthophagus balthasari)总个体数最多(667头)。2)回归分析结果显示,生境数量和生境质量均能显著影响粪食性金龟物种多样性,但气象因子影响不显著。粪食性金龟总个体数与林地面积、灌丛面积显著正相关(p<0.05);物种丰富度与灌丛面积显著正相关(p<0.05);Hill-Shannon多样性与灌丛面积、草地面积、归一化植被指数(NDVI)显著正相关(p<0.05);Hill-Shannon均匀度与灌丛面积显著负相关(p<0.05)。3)基于Akaike信息量准则(AIC)和方差分解分析(Variance Partitioning Analysis)结果显示,生境数量解释粪食性金龟物种多样性相对重要性最高,对总个体数、物种丰富度、Hill-Shannon均匀度的独立效应最高,分别为21.3%、17.8%、15.6%。综上,灌丛面积、林地面积、草地面积、NDVI是影响粪食性金龟物种多样性的关键因子,生境数量相比于生境质量和气象因子更能影响其物种多样性。合理规划城市植被覆盖面积以及保护现有植被质量是保护粪食性金龟物种多样性的有效措施。

Urbanization is one of the most detrimental forms of land use,frequently leading to environmental changes that result in a decline in biodiversity.Exploring the effects of environmental factors(amount of habitat,habitat quality,and meteorological factors)on the diversity of dung beetles,a key environmental indicator species,is crucial for urban biodiversity conservation.In this study,18 plots across three habitat types(woodland,shrubland,and grassland)and with varying urbanization levels(urban,suburban,and rural)were selected in Chengdu during July and September 2021.Dung beetles were captured by pitfall traps baited with rotten fish.The results showed that 1)a total of 1149 dung beetles from five genera and eight species were collected,all belonging to the same behavioral type(tunnelers)and predominantly small in size(body length<13.0 mm).Onthophagus was the dominant genus in the study area(four species,1066 individuals),with Onthophagus balthasari as the most abundant species(667 individuals).2)Regression analyses showed that both habitat amount and quality significantly influenced dung beetle species diversity,whereas meteorological factors had no significant effect.The total number of individuals was significantly and positively correlated with woodland area and shrubland area(p<0.05),species richness was significantly and positively correlated with shrubland area(p<0.05),Hill-Shannon diversity was significantly and positively correlated with shrubland area,grassland area,and Normalized Difference Vegetation Index(NDVI)(p<0.05),and Hill-Shannon evenness was significantly negatively correlated with shrubland area(p<0.05).3)Based on the Akaike Information Criterion(AIC)and Variance Partitioning Analysis,the results indicated that habitat amount had the highest relative importance in explaining dung beetle diversity,with independent effects on the total number of individuals,species richness,and Hill Shannon evenness at 21.3%,17.8%,and 15.6%,respectively.In conclusion,woodlands,shrublands,grassland areas,and NDVI were key determinants of dung beetle diversity.Habitat quantity surpasses habitat quality and the meteorological factors that influence dung beetle diversity.Reasonable improvement in vegetation coverage and existing vegetation quality is an effective measure for protecting the diversity of dung beetles in urban areas.