Impact of adjacent land use on the ecological condition of riparian habitats: The relation between condition and vegetation properties

Abstract

Questions: The ecological condition of riparian habitats has been negatively altered by human activities and land-use changes. The aims of this study were to evaluate: (a) how adjacent land use affects the ecological condition of riparian habitats; and (b) whether the ecological condition relates to riparian vegetation properties (i.e., structure, diversity, and species composition). Location: Watershed of the Duero River, in the state of Michoacán, Mexico. Methods: Sampling sites were established along the Duero River riverbank by considering three different land uses (i.e., native forest, agriculture, and urban). At each site, we assessed the ecological condition of riparian habitats with a riparian condition index (RCI) composed of six subindices, with 17 indicators. Using a survey of woody plants (DBH ≥ 2.5 cm) in 12 different 0.1-ha sites, we assessed vegetation properties. Results: According to the RCI, 76% of the studied riparian habitats had a very poor ecological condition, and only one site scored an excellent condition. The values of all subindices as well as the RCI were significantly greater in the forest than in the agricultural or urban land uses. The significant relationships between the RCI and its components (subindices) with vegetation properties were all positive and explained between 22% and 73% of the variation in structural and diversity attributes, and between 48% and 66% in floristic composition. Conclusions: This study shows how human land-use activities affect the ecological condition of riparian habitats and hence riparian forests. Overall, the RCI had a high predictive power for the vegetation properties of riparian forests. This information is critical for programs involved in the management, conservation, and ecological restoration of riparian habitats. Low-cost and time-efficient indices, such as the RCI, facilitate ecological condition assessments of riparian habitats not only by scientists but also by previously trained land managers and the general public. | 611 Applied Vegetation Science ZERMEÑO-HERNÁNDEZ Et al.

Riparian Vegetation Structure Influences Terrestrial Invertebrate Communities in an Agricultural Landscape

“…Zermeño-Hernández et al [68] found that the structure and diversity of riparian vegetation were strongly influenced by the riparian condition. In our study, the lower abundances of web-building spiders (e.g., Tetragnathidae) at unbuffered sites in the Arges , basin are likely the result of reduced habitat for web construction.…”

“…However, managing stream-riparian networks needs to embrace a multifunctional perspective that accounts for positive co-benefits as well as ecosystem disservices. For example, patches of riparian forest in catchments can help protect stream health (e.g., stabilizing streambanks and shading the channel, helping to regulate water quality and stream temperatures, providing plant litter and woody detritus inputs for shredding invertebrates) [6,10,68]. Forested riparian buffers can also provide refuge (microclimatic conditions, overwintering, or aestivation sites) and food resources for natural enemies of crop pests [119].…”

Vegetation Properties in Human-Impacted Riparian Zones Based on Unmanned Aerial Vehicle (UAV) Imagery: An Analysis of River Reaches in the Yongding River Basin

“…The impact of human activities on the vegetation in the riparian zone is mainly expressed through the construction of dams to regulate water flow, ecological water replenishment, projects for riparian restoration, farmland encroachment, grazing and trampling of cattle and sheep, and the destruction of riverbeds and riparian zones caused by the illegal mining of river sands [45,[47][48][49]. The southern bank of the reach selected The impact of human activities on the vegetation in the riparian zone is mainly expressed through the construction of dams to regulate water flow, ecological water replenishment, projects for riparian restoration, farmland encroachment, grazing and trampling of cattle and sheep, and the destruction of riverbeds and riparian zones caused by the illegal mining of river sands [45,[47][48][49]. The southern bank of the reach selected from the Dongyang River was more severely grazed by cattle and sheep, so the vegetation cover was sparser compared to the northern bank (Figure 4 and Figure S3a).…”

Spatial prioritization for widespread invasive species control: Trade‐offs between current impact and future spread

“…To represent the management goal of preferencing control at locations in good condition, we developed a condition rating based on Victorian land-use data (Morse-McNabb et al, 2015). We used land-use data as they are a good indicator of riparian vegetation and stream condition (Lohse et al, 2008;Zermeño-Hern andez et al, 2020) and were readily available (Appendix S1: Section S5). Land-use categories were aggregated into six classes thought to reflect different levels of riparian condition (Appendix S1: Table S3) and allocated scores to represent the relative effect of each land-use category on condition (Appendix S1: Table S4).…”