Spatiotemporal interactions of a novel mesocarnivore community in an urban environment before and during SARS-CoV-2 lockdown

Abstract

Studying species interactions and niche segregation under human pressure provides important insights into species adaptation, community functioning and ecosystem stability. Due to their high plasticity in behaviour and diet, urban mesocarnivores are ideal species for studying community assembly in novel communities. We analysed the spatial and temporal species interactions of an urban mesocarnivore community composed of the red fox Vulpes vulpes and the marten Martes sp. as native species, the raccoon Procyon lotor as invasive species, and the cat Felis catus as a domestic species in combination with human disturbance modulated by the SARS-CoV-2 lockdown effect that happened while the study was conducted. We analysed camera trap data and applied a joint species distribution model to understand not only the environmental variables influencing the detection of mesocarnivores and their use intensity of environmental features but also the species' co-occurrences while accounting for environmental variables. We then assessed whether they displayed temporal niche partitioning based on activity analyses, and finally analysed at a smaller temporal scale the time of delay after the detection of another focal species. We found that species were more often detected and displayed a higher use intensity in gardens during the SARS-CoV-2 lockdown period, while showing a shorter temporal delay during the same period, meaning a high human-induced spatiotemporal overlap. All three wild species spatially co-occurred within the urban area, with a positive response of raccoons to cats in detection and use intensity, whereas foxes showed a negative trend towards cats. When assessing the temporal partitioning, we found that all wild species showed overlapping nocturnal activities. All species displayed temporal segregation based on temporal delay. According to the temporal delay analyses, cats were the species avoided the most by all wild species. To conclude, we found that although the wild species were positively associated in space, the avoidance occurred at a smaller temporal scale, and human pressure in addition led to high spatiotemporal overlap. Our study sheds light to the complex patterns underlying the interactions in a mesocarnivore community both spatially and temporally, and the exacerbated effect of human pressure on community dynamics.

Keywords: SARS-CoV-2 lockdown effect; activity patterns; camera trap; joint species distribution models; mesocarnivores; spatial niche; temporal niche partitioning; urban ecology.

FIGURE 1

Camera trap locations in Berlin for the five sampling phases: fall 2018, spring 2019, fall 2019, spring 2020 and fall 2020, and number of days with pictures taken during those sampling phases

FIGURE 2

Representation of the measure of time of delay between two species of the mesocarnivore community of Berlin based on camera traps. Animal silhouettes by AP and MS

FIGURE 3

Effects of season including SARS‐CoV‐2 lockdown, garden covariates, urban covariates and presence of cats on the presence (a) and use intensity (b) of urban mesocarnivores in citizen's gardens of Berlin. Thin lines represent 95% credible intervals (CRI), and thick lines represent 50% CRI

FIGURE 4

Relative importance of the different variable groups for the detection (a), use intensity (b) analyses, divided by mesocarnivore species. Variables were grouped into: season, SARS‐CoV‐2 lockdown effects, garden variables, urban variables and effects of cats. The random factor in all analyses refers to the garden identity. Mean values for all species in each analysis are shown to the right of the plots

FIGURE 5

Species association in the residual variance of the JSDM analyses. Colour and width of the arrows represent the correlation value between two species. Solid lines are used for significant correlations and dashed lines are used for non‐significant correlations. Animal silhouettes by AP and MS

FIGURE 6

Activity patterns of each species composing the mesocarnivore community of Berlin, before the SARS‐CoV‐2 lockdown measures were in place (Covid) and were not in place (No Covid)

FIGURE 7

Effects of season, SARS‐CoV‐2 lockdown, garden covariates, urban covariates and first detected species, on the time of delay by urban mesocarnivores to get detected in gardens, and their 95% CRI estimated by the mixed model

FIGURE 8

Predicted values of time of delay (hours) for each of the four mesocarnivore species of Berlin, depending on the species after which they were detected, and whether the SARS‐CoV‐2 lockdown was in effect or not