Influence of the COVID-19 pandemic on amphibian road mortality

Lockdown's Silver Lining? Different Levels of Roadkill during the COVID-19 Times in Lithuania

The impact of COVID-19 restrictions on human and vehicular mobility on the number of roadkills of wild mammals, and roe deer in particular, was assessed in Lithuania. We statistically analyzed the distribution of all mammals and roe deer (Capreolus capreolus) as the most abundant species annually from 2002 to 2022 and monthly from 2020 to 2021, including during the two restriction periods. Notably, there was a marked decrease in roadkill incidents on main, national and regional roads, particularly in April-May 2020 (the beginning of lockdown period I) and November-December 2020 (the beginning of lockdown period II), 5.1-20.8% and 33.6-54.4%, respectively. During these months, collisions with mammals on the A14 main road were reduced by 75-90%. However, there was a significant increase in the number of roadkills in urban areas, resulting in the total number of mammal-vehicle and roe deer-vehicle collisions in 2020 and 2021 being higher than expected based on long-term trends. However, after restrictions were eased, collision numbers with wildlife on the main, national and regional roads increased again and became higher than expected.

Worse sleep and increased energy expenditure yet no movement changes in sub-urban wild boar experiencing an influx of human visitors (anthropulse) during the COVID-19 pandemic

Expansion of urban areas, landscape transformation and increasing human outdoor activities strongly affect wildlife behaviour. The outbreak of the COVID-19 pandemic in particular led to drastic changes in human behaviour, exposing wildlife around the world to either reduced or increased human presence, potentially altering animal behaviour. Here, we investigate behavioural responses of wild boar (Sus scrofa) to changing numbers of human visitors to a suburban forest near Prague, Czech Republic, during the first 2.5 years of the COVID-19 epidemic (April 2019-November 2021). We used bio-logging and movement data of 63 GPS-collared wild boar and human visitation data based on an automatic counter installed in the field. We hypothesised that higher levels of human leisure activity will have a disturbing effect on wild boar behaviour manifested in increased movements and ranging, energy spent, and disrupted sleep patterns. Interestingly, whilst the number of people visiting the forest varied by two orders of magnitude (from 36 to 3431 people weekly), even high levels of human presence (>2000 visitors per week) did not affect weekly distance travelled, home range size, and maximum displacement of wild boar. Instead, individuals spent 41 % more energy at high levels of human presence (>2000 visitors per week), with more erratic sleep patterns, characterised by shorter and more frequent sleeping bouts. Our results highlight multifaceted effects of increased human activities ('anthropulses'), such as those related to COVID-19 countermeasures, on animal behaviour. High human pressure may not affect animal movements or habitat use, especially in highly adaptable species such as wild boar, but may disrupt animal activity rhythms, with potentially detrimental fitness consequences. Such subtle behavioural responses can be overlooked if using only standard tracking technology.

The presence of COVID-19 face masks in the largest hypersaline lagoon of South America is predicted by urbanization level

The inadequate disposal of face masks has caused a widespread presence of COVID-19 litter in the environment. We monitored 10 beach arcs along approximately 15 km of the largest hypersaline lagoon of South America looking for face masks during the lockdown (2021) and in the "new normal" (2022) period. Our working hypothesis is that the probability of finding face masks increases with higher urbanization levels, which was estimated by the Human Modification Metric. Approximately 3 × 10^-3 face masks m^-2 were found on nine of 10 beaches (90 %) during the lockdown. However, this reduced to 1 × 10^-4 face masks m^-2 found in eight beaches (80 %) after the lockdown. The probability of finding a face mask was significantly higher as urbanization increased (z = 2.799; p = 0.005). This situation imposes the need for a better waste management and environmental education actions, targeting the reduction of direct littering on coastal ecosystem.

Avian behaviour changes in response to human activity during the COVID-19 lockdown in the United Kingdom

Human activities may impact animal habitat and resource use, potentially influencing contemporary evolution in animals. In the United Kingdom, COVID-19 lockdown restrictions resulted in sudden, drastic alterations to human activity. We hypothesized that short-term daily and long-term seasonal changes in human mobility might result in changes in bird habitat use, depending on the mobility type (home, parks and grocery) and extent of change. Using Google human mobility data and 872 850 bird observations, we determined that during lockdown, human mobility changes resulted in altered habitat use in 80% (20/25) of our focal bird species. When humans spent more time at home, over half of affected species had lower counts, perhaps resulting from the disturbance of birds in garden habitats. Bird counts of some species (e.g. rooks and gulls) increased over the short term as humans spent more time at parks, possibly due to human-sourced food resources (e.g. picnic refuse), while counts of other species (e.g. tits and sparrows) decreased. All affected species increased counts when humans spent less time at grocery services. Avian species rapidly adjusted to the novel environmental conditions and demonstrated behavioural plasticity, but with diverse responses, reflecting the different interactions and pressures caused by human activity.

Recovery of ghost crabs metapopulations on urban beaches during the Covid-19 "anthropause"

The majority of government authorities initially responded to COVID-19 pandemic by declaring lockdown to facilitate social distancing and minimize virus spreading. This period termed "anthropause" provided a unique opportunity to evaluate the recovery of wildlife in the absence of stressors on urban ecosystems. We assessed whether the anthropause associated with beach closures during the COVID-19 pandemic resulted in repopulation of the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) on urban beaches. For this purpose, we compiled a historic dataset (2013-2019) of the ghost crab density and performed biweekly burrow measurements from June/2020 to May/2021. Recovery of ghost crab metapopulation during the lockdown occurred even in more human-modified beaches. Burrow abundance significantly increased in urban sectors, but not in control site along with the time of pandemic. The reduction in the mean burrow opening diameter during this period evidenced that young metapopulation have thrived on urban beaches when recreational activities ceased. Our results show that urban beaches should not be exclusively managed for recreational purposes. Initiatives with a focus on wildlife conservation including spatial-temporal controlled beach closures may increase the biodiversity resilience.

Estimating Road Mortality Hotspots While Accounting for Imperfect Detection: A Case Study with Amphibians and Reptiles

Wildlife road mortality tends to aggregate spatially at locations commonly referred to as road mortality hotspots. Predictive models can be used to identify locations appropriate for mitigation measures that reduce road mortality. However, the influence of imperfect detection (e.g., false absences) during road mortality surveys can lead to inaccurate or imprecise spatial patterns of road mortality hotspots and suboptimal implementation of mitigation measures. In this research, we used amphibians and reptiles as a case study to address imperfect detection issues when estimating the probability of road mortality hotspots using occupancy detection modeling. In addition, we determined the survey effort needed to achieve a high probability of detecting large roadkill events. We also assessed whether vehicle travel reductions associated with the COVID-19 pandemic travel restrictions led to reductions in road mortality. We conducted surveys at 48 sites throughout Rhode Island, USA, from 2019–2021. In total, we observed 657 carcasses representing 19 of Rhode Island’s 37 native species. Of the 19 native species, eight species of frogs, four species of salamanders, four species of snakes, and three species of turtles were observed. We documented a reduction in roadkill density and the proportion of dead versus live amphibians and reptiles in pandemic years (2020 and 2021), but we were unable to link reductions in roadkill density to reductions in traffic volume. Our model results indicated that large roadkill events were more likely to occur on roads near wetlands and with low traffic volume and were more likely to be detected as daily precipitation increased. We determined that there was a low probability of detecting large roadkill events, suggesting that imperfect detection influences detection of large roadkill events, and many were likely missed during our surveys. Therefore, we recommend using occupancy modeling to account for the influence of imperfect detection when estimating road mortality hotspots. This approach will more effectively guide the implementation of mitigation measures.

Anthropause Opportunities: Experimental Perturbation of Road Traffic and the Potential Effects on Wildlife

The SARS-CoV-2 pandemic severely reduced many human activities. So pronounced was the change, it has given rise to the term “anthropause”: the considerable alteration of modern human activities. Among these was surface transportation, with prolonged traffic reductions, in excess, of 50% in many countries. Roads and traffic are responsible for functionally fragmenting ecosystems, wildlife populations, and species interactions. The unintentional “dialing-down” of traffic has given continuous monitoring systems of wildlife-vehicle conflict a unique opportunity to study the consequences of perturbing this source of wildlife disturbance and mortality. Experimental manipulation of traffic at the global scale would not have been possible without mitigation responses to SARS-CoV-2. Such a perturbation allows robust empirical investigation into wildlife responses to traffic, including changes in mortality, behavior, genetic connectivity, and knock-on ecosystem effects, the responses to which can be replicated across a global network of wildlife-vehicle conflict monitoring systems. We review the extent to which these extensive data-collection systems provide the primary source of data to study many of these responses, providing the raw material to understand some striking wildlife consequences of the anthropause.