The Resilience of Polar Collembola (Springtails) in a Changing Climate

Abstract

Assessing the resilience of polar biota to climate change is essential for predicting the effects of changing environmental conditions for ecosystems. Collembola are abundant in terrestrial polar ecosystems and are integral to food-webs and soil nutrient cycling. Using available literature, we consider resistance (genetic diversity; behavioural avoidance and physiological tolerances; biotic interactions) and recovery potential for polar Collembola. Polar Collembola have high levels of genetic diversity, considerable capacity for behavioural avoidance, wide thermal tolerance ranges, physiological plasticity, generalist-opportunistic feeding habits and broad ecological niches. The biggest threats to the ongoing resistance of polar Collembola are increasing levels of dispersal (gene flow), increased mean and extreme temperatures, drought, changing biotic interactions, and the arrival and spread of invasive species. If resistance capacities are insufficient, numerous studies have highlighted that while some species can recover from disturbances quickly, complete community-level recovery is exceedingly slow. Species dwelling deeper in the soil profile may be less able to resist climate change and may not recover in ecologically realistic timescales given the current rate of climate change. Ultimately, diverse communities are more likely to have species or populations that are able to resist or recover from disturbances. While much of the Arctic has comparatively high levels of diversity and phenotypic plasticity; areas of Antarctica have extremely low levels of diversity and are potentially much more vulnerable to climate change.

Keywords: Antarctic; Arctic; Climate Change; Ecology; Genetic diversity; Physiology.

Fig. 1

Arctic and Antarctic regions showing place names used in the manuscript. Key differences between the polar regions are highlighted in the boxes to the right of the maps: A) Map showing Arctic circle at 66°33′N (black-dashed circle) and the boundary for the Conservation of Arctic Flora and Fauna (red solid line); and B) Key regions of the Antarctic continent and Maritime Antarctic Islands. The approximate location of the Antarctic Polar Front is indicated by a red dashed line. Both poles are indicated by a + symbol. (Base maps sourced from https://d-maps.com/carte.php?num_car=3197&lang=en; and https://data.aad.gov.au/aadc/mapcat/display_map.cfm?map_id=13137).

Fig. 2

Examples of: A) an epiedaphic (surface-dwelling) Collembola (Isotomurus sp. from the Canadian Arctic) showing elongated appendages including legs, antennae, furcula (indicated by blue arrow), and ‘ventral tube’ (collophore, visible between the second and third pairs of legs); B) an eudaphic taxon (Tullbergia mediantarctica) from the southern Transantarctic Mountains, showing lack of pigmentation or eye spots, short appendages and absence of a furcula; and C) an Antarctic hemiedaphic (intermediate soil profile) taxon from the Antarctic Dry Valleys (Gomphiocephalus hodgsoni), showing reduced appendages and furcula (indicated by blue arrow). Scale bars (500um) are shown for each taxon. All images copyright University of Waikato.

Fig. 3

Conceptual diagram showing a hypothetical and fluctuating press disturbance (A) and corresponding ecological response (B) resulting from climate change. Once maximal tolerance limits (maximum resistance capacity) are exceeded, steep declines in associated ecological responses such as fecundity or abundance are expected (B). Increased tolerance levels increases initial resistance (C), which may delay ecological responses (D). The fluctuating nature of almost all climates allow opportunities for recovery (*) which can influence ongoing resistance capacities.