Dynamic Responses of Ground-Dwelling Invertebrate Communities to Disturbance in Forest Ecosystems

Abstract

In forest ecosystems, natural and anthropogenic disturbances alter canopy structure, understory vegetation, amount of woody debris, and the properties of litter and soil layers. The magnitude of these environmental changes is context-dependent and determined by the properties of the disturbance, such as the frequency, intensity, duration, and extent. Therefore, disturbances can dynamically impact forest communities over time, including populations of ground-dwelling invertebrates that regulate key ecosystem processes. We propose conceptual models that describe the dynamic temporal effects of canopy gap formation and coarse woody debris accumulation following disturbances caused by invasive insects, wind, and salvage logging, and their impacts on ground-dwelling invertebrate communities. Within this framework, predictions are generated, literature on ground-dwelling invertebrate communities is synthesized, and pertinent knowledge gaps identified.

Forest disturbance and arthropods: Small‐scale canopy gaps drive invertebrate community structure and composition

“…Dispersal potential of ground-dwelling arthropods was generally limited for most taxa , and movement was further reduced following combined canopy and ground-level understory disturbances utilized in this study (Perry 2016). Millipedes generally displayed high dispersal potential ), but their movement, especially Paradoxosomatidae, was reduced in the most disturbed treatments with canopy gaps and understory vegetation removed (Perry 2016). Activity-abundances of Caseyidae and Julidae increased in the most disturbed treatments with canopy gaps and the understory removed, whereas Polydesmidae and Paradoxosomatidae increased in all of the disturbance treatments.…”

“…Increased soil temperatures and moisture levels create a conducive environment for decomposition, and increased mineralization and nitrification have been observed in forest openings (Likens et al 1978, Runkle 1985. This finding suggests that the majority of invertebrates remained within the disturbed patches (Perry 2016), perhaps due to the abundance of available resources in gaps. Several epedaphic families of Collembola (Isotomidae, Tomoceridae, Dicyrtomidae, and Katiannidae), as well as common detritivores (Caseyidae, Paradoxosomatidae, Isopoda, and Scarabaeidae) and predators (Araneae, Carabidae, and Staphylinidae), were more abundant in canopy gap treatments.…”

“…Not only were these taxa more abundant in canopy gaps, they also tended to stay in the gaps, but with increased local movement (<1-5 m), as evidenced from a companion markcapture study conducted simultaneously in the same experimental quadrats (Perry 2016). Decoupling of canopy and understory vegetation disturbances revealed canopy gap formation as an important short-term driver of ground-dwelling invertebrate community structure and composition, affecting the activity-abundance of diverse functional guilds, including predators, detritivores, and fungivores.…”

“…General habitat requirements may have primed these ground beetle species to take advantage of the abundant prey in canopy gap treatments, allowing them to remain in the disturbed patch. Patterns of movement of ground-dwelling invertebrates were mostly local in canopy gap treatments, as the majority of individuals dispersed only a short distance (<1-5 m) than those in undisturbed treatments (6-≥13 m;Perry 2016). This finding suggests that the majority of invertebrates remained within the disturbed patches (Perry 2016), perhaps due to the abundance of available resources in gaps.…”

“…Neanuridae, Hypogastruridae, and Entomobryidae, all families of Collembola, increased following understory vegetation removal, even though movement of Collembola was lower (Perry 2016). Although differences in understory cover and height were greatest between undisturbed and removal treatments following implementation in 2014, invertebrate richness initially was unaffected.…”