Human-made transportation systems such as roads, railways, and canals are found almost everywhere on Earth, allowing faster and easier movement of people, goods, and services than at any other time in history. This transportation infrastructure is critical to our modern way of life, yet may also have profound effects on the ecology of plants and animals across the world.
The negative effects of transportation systems have been well documented, particularly their role in severely fragmenting natural landscapes and creating barriers to the movement of many organisms. However, there has been increasing recognition that transportation infrastructure can also have positive effects by providing habitat and acting as corridors for some plants and animals.
A new study by Villemey et al. 2018 uses a meta-analysis approach to systematically examine the existing body of scientific literature about transportation infrastructure as habitat for insects. In their analysis, the authors considered any studies on habitat associated with transportation infrastructure, including power line cuts, strips of grass above buried pipelines, waterway banks, train embankments, and roadside verges.
Looking across 91 scientific papers, the authors found that there was great variability in the effects of transportation infrastructure on insect communities. Some types of infrastructure systems such as waterways had a largely negative effect on insects, while others such as roadside verges significantly increased insect abundance.
Overall, habitat associated with transportation infrastructure often contained similar to higher insect abundance and diversity than in surrounding habitats, particularly when the habitat was restored and managed.
Through their work, Villemey et al. identified several potential biases and gaps in the current literature that could be filled through future research. The authors found that most work on transportation infrastructure as habitat is relatively recent; the earliest paper included in their study was published in 1974, and by far the highest number of papers on the subject were published within the past five years.
In addition, studies predominantly focused on a subset of insect groups including butterflies, beetles, and bees. Though many studies focused on the use of transportation infrastructure as habitat for insects, very few studies looked at their effect on insect movement.
Within their review, only two studies explicitly examined the role of transportation infrastructure as habitat corridors.
The findings of this systematic review show that there is much more work to be done examining the landscape-level effects of transportation infrastructure on insect communities. Based on these results, habitats such as roadside verges and railway embankments can serve as good habitat for diverse insect communities, but their full potential for conservation or facilitating insect dispersal remains unknown due to a lack of research.
Because transportation infrastructure is so common and important to human well-being around the world, there is a strong need to understand both how these systems impact landscapes as well as ways to make them better for plants and animals of conservation interest.
Villemey, A., A. Jeusset, M. Vargac, Y. Bertheau, A. Coulon, J. Touroult, S. Vanpeene, B. Castagneyrol, H. Jactel, I. Witte, N. Deniaud, F. Flamerie De Lachapelle, E. Jaslier, V. Roy, E. Guinard, E. Le Mitouard, V. Rauel, and R. Sordello. 2018. Can linear transportation infrastructure verges constitute a habitat and/or a corridor for biodiversity in temperate landscapes? A systematic review. Environmental Evidence 7:5.