研究问题Research question

为什么有些水生昆虫能跨越较大的海拔范围，而另一些分布较窄？围绕Janzen热带山口假说，研究比较热生态位、局域生境生态位、局部丰度与功能性状的相对重要性，并探讨这些因素共同关联海拔分布范围的路径。Why do some stream insects occupy broad elevational ranges while others have more restricted distributions? Motivated by Janzen’s tropical mountain passes hypothesis, this study compared the relative importance of thermal and local habitat niches, local abundance and functional traits, and examined the pathways linking these factors to elevational range size.

研究设计与分析Study design & analysis

参与课题组合作研究，以南岭约1400米海拔梯度上的52个未受干扰溪流河段为对象，分别量化热生态位与局域生境生态位的宽度和位置。采用系统发育线性回归及相应的层次分割，在控制系统发育相关性的基础上，比较生态位特征、局部丰度和功能性状的相对解释贡献；进一步通过分段结构方程模型，分析生态位与海拔分布范围之间的直接关联，以及经局部丰度传递的间接路径。In this collaborative study, 52 undisturbed stream reaches along an approximately 1,400 m elevational gradient in the Nanling Mountains were used to quantify the breadth and position of thermal and local habitat niches. Phylogenetic linear regression and hierarchical partitioning compared the relative explanatory contributions of niche characteristics, local abundance and functional traits while accounting for phylogenetic relatedness. Piecewise structural equation models then assessed direct relationships with elevational range size and indirect pathways mediated by local abundance.

主要发现Key findings

海拔分布范围与局部丰度、生态位宽度呈正相关，与生态位位置呈负相关。相比局部丰度和功能性状，生态位特征的解释作用更突出，其中热生态位宽度是最重要的解释因素。Elevational range size was positively associated with local abundance and niche breadth, but negatively associated with niche position. Niche characteristics were more important explanatory factors than local abundance and functional traits, with thermal niche breadth making the strongest contribution.

结构方程模型进一步表明，热生态位宽度与位置主要通过直接路径关联海拔分布范围；经局部丰度传递的间接作用相对较弱，凸显了热生态位特征对区域海拔分布格局的重要性。Structural equation models further indicated that thermal niche breadth and position were primarily linked to elevational range size through direct pathways. Indirect relationships mediated by local abundance were comparatively weak, highlighting the importance of thermal niche characteristics for regional elevational distributions.

生态意义Ecological implications

研究为Janzen热带山口假说在类热带山地溪流中的适用性提供了支持，并将热生态位特征与区域海拔分布格局联系起来。结果提示，热生态位较窄、海拔分布受限的水生昆虫可能对持续升温更为敏感，应成为气候变化背景下的重要保护关注对象。These findings support Janzen’s hypothesis in a tropical-like mountain stream system by linking thermal niche characteristics to regional elevational distributions. Stream insects with narrow thermal niches and restricted elevational ranges may be particularly sensitive to continued warming and warrant conservation attention as climate change accelerates.

研究问题Research question

土地利用变化带来的，是否不仅是溪流物种组成的改变，还有群落功能多样性的下降？这些差异与哪些环境因素相关，又是否随丰、枯水期而变化？Is land-use change associated with a loss of functional diversity as well as changes in stream species composition? Which environmental factors explain these differences, and do their relative contributions vary between wet and dry seasons?

研究设计与分析Study design & analysis

于2024年9月（丰水期）和2025年1月（枯水期）调查南岭21条溪流，包括10条参照溪流和11条受土地利用变化影响的溪流，共鉴定出180个底栖动物分类单元。采用Ricotta等（2023）的解析框架，比较物种优势度（D）、功能多样性（Q）与功能冗余度（R），并结合多元线性回归和层次分割，评估区域土地利用、局域物理与水化学环境及空间因子的相对解释贡献。Surveys in September 2024 (wet season) and January 2025 (dry season) covered 21 Nanling streams: 10 reference streams and 11 affected by land-use change, yielding 180 macroinvertebrate taxa. Ricotta et al.’s (2023) framework was used to compare species dominance (D), functional diversity (Q) and functional redundancy (R). Multiple linear regression and hierarchical partitioning assessed the relative explanatory contributions of catchment land use, local physical and water-chemistry conditions, and spatial factors.

主要发现Key findings

受损溪流的功能多样性显著低于参照溪流，并呈现更高的功能同质化；两类溪流的物种组成仅在枯水期存在显著差异。各类因子的解释作用也具有季节依赖性：丰水期，局域环境和空间因子的作用较为突出；枯水期，土地利用与水化学因素的相对重要性增强。Impacted streams had significantly lower functional diversity and greater functional homogenization. Species composition differed significantly between reference and impacted streams only in the dry season. Explanatory patterns were also season dependent: local environmental and spatial factors were more prominent in the wet season, while land use and water chemistry gained relative importance in the dry season.

生态意义Ecological implications

功能多样性提供了物种组成之外的群落变化信息。溪流生态状况评价与恢复成效评估，应将其作为分类学多样性的重要补充，并结合不同水文季节下主要环境因素的变化，制定更有针对性的保护与管理措施。Functional diversity reveals community changes beyond species composition. Stream ecological assessment and restoration evaluation should therefore complement taxonomic diversity with functional diversity and account for seasonal shifts in the main environmental factors to guide conservation and management.

研究问题Research question

今天的河流生物多样性，是否仍受过去气候与土地利用变化的影响？在快速城市化背景下，哪类历史变化的遗留作用更强，分类多样性与功能多样性的响应又是否一致？Does present-day river biodiversity still reflect past climate and land-use changes? In rapidly urbanizing catchments, which environmental history leaves the stronger legacy, and do taxonomic and functional diversity respond in the same way?

研究设计与分析Study design & analysis

2019—2021年在深圳48个河流样点采集底栖动物，结合线性混合效应模型与层次分割，比较当代环境与历史环境变化的解释作用。设置四个时间窗口：1985—2020年、2000—2020年代表较长期变化，2005—2020年、2010—2020年代表较近期变化，分别评估气候与土地利用的独立效应及交互作用。Macroinvertebrates were sampled at 48 river sites in Shenzhen during 2019–2021. Linear mixed-effects models and hierarchical partitioning compared contemporary and historical environmental effects across four windows: 1985–2020 and 2000–2020 for relatively long-term change, and 2005–2020 and 2010–2020 for more recent change. Analyses assessed the independent effects of climate and land use alongside their interactions.

主要发现Key findings

当代升温和土地利用强度增加与分类、功能多样性降低及功能冗余度升高相关。历史环境对当代多样性的解释贡献往往超过当代环境，其中历史土地利用变化、尤其不透水面扩张的独立效应强于气候变化。Contemporary warming and greater land-use intensity were associated with lower taxonomic and functional diversity, but higher functional redundancy. Historical environmental contributions often exceeded those of contemporary conditions. Historical land-use change, particularly impervious surface expansion, had stronger independent effects than climate change.

气候与土地利用的交互作用总体较弱，但在较近期的时间窗口中相对重要性上升。功能多样性的遗留响应强于分类多样性，表明性状指标能够揭示仅靠分类指标难以察觉的生态变化。Climate–land-use interactions were generally weak, but gained relative importance in more recent windows. Functional diversity showed stronger legacy responses than taxonomic diversity, indicating that trait-based metrics can reveal ecological changes less apparent from taxonomic metrics alone.

生态意义Ecological implications

理解河流现状，需要同时考虑当代环境与历史变化轨迹。将环境遗留效应和功能多样性纳入淡水监测与管理，有助于在持续气候变化和城市扩张背景下，更合理地开展河流修复、生物多样性保护与城市规划。Understanding a river’s present condition requires both contemporary conditions and historical environmental trajectories. Incorporating legacy effects and functional biodiversity into freshwater monitoring and management can better inform river restoration, biodiversity conservation and urban planning under continued climate change and urban expansion.

研究问题Research question

保护区是否充分守护了溪流水生昆虫的物种与演化多样性？保护区之外的溪流，即使物种较少，是否仍保存着具有独特保护价值的演化谱系？How well do protected areas safeguard aquatic insect diversity and evolutionary history? Can surrounding streams with fewer taxa still harbor lineages of distinctive conservation value?

研究设计与分析Study design & analysis

比较南岭保护区与邻近非保护区溪流水生昆虫群落的分类多样性、系统发育多样性、群落独特性及系统发育结构，并结合流域土地利用、气候、水质、物理生境和空间因素，分析多样性与独特性变化的关联因素。Aquatic insect assemblages in protected and adjacent non-protected Nanling streams were compared in terms of taxonomic diversity, phylogenetic diversity, community uniqueness and phylogenetic structure. Catchment land use, climate, water quality, physical habitat and spatial factors were examined as predictors of diversity and uniqueness.

主要发现Key findings

非保护区溪流的分类与系统发育多样性较低，系统发育聚集更强，与人类干扰下更强的确定性筛选相一致。但其群落系统发育独特性更高，说明保护区边界之外仍保存着对区域演化多样性具有互补贡献的谱系。Non-protected streams had lower taxonomic and phylogenetic diversity and stronger phylogenetic clustering, consistent with stronger deterministic filtering under anthropogenic disturbance. Yet their greater community phylogenetic uniqueness indicated that lineages outside protected boundaries make complementary contributions to regional evolutionary diversity.

多类环境与空间因素共同解释群落差异，其中空间结构和水质的影响较为突出。空间效应提示区域空间背景及连通性相关过程可能发挥作用，但不能作为扩散过程的直接证据。Environmental and spatial factors jointly explained community differences, with spatial structure and water quality among the most influential predictors. Spatial effects highlight the regional spatial context and a possible role for connectivity-related processes, but do not directly demonstrate dispersal.

生态意义Ecological implications

保护区保存了较高的分类与系统发育多样性，周边非保护区则提供独特的互补保护价值。保护策略应兼顾多样性与独特性，将视野延伸至保护区外的溪流网络，通过维持生境连续性、减轻周边环境压力，协同保护区域演化历史。Protected areas conserve broad taxonomic and phylogenetic diversity, while surrounding streams provide complementary value through unique lineages. Conservation should integrate diversity and uniqueness across stream networks beyond protected boundaries, maintain habitat continuity and reduce surrounding environmental pressures to safeguard regional evolutionary history.