Ecological patterns and processes in the vertical dimension of terrestrial ecosystems

Abstract

Climatic gradients such as latitude and elevation are considered primary drivers of global biogeography. Yet, alongside these macro‐gradients, the vertical space and structure generated by terrestrial plants form comparable climatic gradients but at a fraction of the distance. These vertical gradients provide a spectrum of ecological space for species to occur and coexist, increasing biodiversity. Furthermore, vertical gradients can serve as pathways for evolutionary adaptation of species traits, leading to a range of ecological specialisations. In this review, we explore the ecological evidence supporting the proposition that the vertical gradient serves as an engine driving the ecology and evolution of species and shaping larger biogeographical patterns in space and time akin to elevation and latitude. Focusing on vertebrate and invertebrate taxa, we synthesised how ecological patterns within the vertical dimension shape species composition, distribution and biotic interactions. We identify three key ecological mechanisms associated with species traits that facilitate persistence within the vertical environment and draw on empirical examples from the literature to explore these processes. Looking forward, we propose that the vertical dimension provides an excellent study template to explore timely ecological and evolutionary questions. We encourage future research to also consider how the vertical dimension will influence the resilience and response of animal taxa to global change.

Dispersal constrains the biotic connectivity of mountain assemblages

“…Vertical environmental zonation in mountain systems provides a singular context for the evolution of adaptations, as well as the build‐up of specific assemblages (Jacob et al., 2015). Functional traits have evolved in response to the challenges of the environment (Lavorel & Garnier, 2002) and this influences species distributions across environments (McGill et al., 2006; Xing et al., 2023). In particular, dispersal is a pivotal process for a species' resilience and response to changing ecosystems, allowing organisms to track optimal environmental conditions.…”

Ecological factors and parity mode correlate with genome size variation in squamate reptiles

“…That is consistent with our observation on arboreal species having significantly larger genomes. Species that live in the canopy layer experience higher levels of solar radiation than ground dwellers so that a relatively larger genome might increase resistance to DNA damages caused by ultraviolet light [ 59 , 60 ]. A similar pattern was observed in birds, whereby arboreal species showed larger genome sizes than species living in open environments [ 61 ].…”

Feedback loops between 3D vegetation structure and ecological functions of animals

“…Ecoregions with diverse vegetation structure broaden the diversity of movement strategies that are possible for animals to use, especially among arboreal lineages (Scheffers et al, 2017). Structural diversity also promotes functional diversity by increasing trophic niche space (Pawar et al, 2012; Xing et al, 2023), a key factor driving variation in morphological form and ecological function (Pigot et al, 2020). Moreover, the structural complexity of vegetation indicates potential risks and resource availability, albeit in environments where the cognitive load of memorizing the 3D environment is not too high (Fagan et al, 2013).…”