Assessing Surveillance of Wildlife Diseases by Determining Mammal Species Vulnerability to Climate Change

Abstract

Climate change is one of the drivers of wildlife-borne disease emergence, as it can affect species abundance and fitness, host immunocompetence, and interactions with pathogens. To detect emerging wildlife-borne diseases, countries may implement general wildlife-disease surveillance systems. Such surveillance exists in the Netherlands. However, it is unclear how well it covers host species vulnerable to climate change and consequently disease emergence in these species. Therefore, we performed a trait-based vulnerability assessment (TVA) to quantify species vulnerability to climate change for 59 Dutch terrestrial mammals. Species' vulnerability was estimated based on the magnitude of climatic change within the species' distribution (exposure), the species' potential to persist in situ (sensitivity), and the species' ability to adjust (adaptive capacity). Using these vulnerability categories, we identified priority species at risk for disease emergence due to climate change. Subsequently, we assessed the frequency of occurrence of these priority species compared to other mammal species examined in general wildlife disease surveillance during 2008-2022. We identified 25% of the mammal species to be highly exposed, 24% to be highly sensitive, and 22% to have a low adaptive capacity. The whiskered myotis and the garden dormouse were highly vulnerable (i.e., highly exposed, highly sensitive, and low adaptive capacity), but they are rare in the Netherlands. The Western barbastelle, the pond bat, and the Daubenton's myotis were potential adapters (highly exposed, highly sensitive, and high adaptive capacity). Species vulnerable to climate change were relatively poorly represented in current general surveillance. Our research shows a comprehensive approach that considers both exposures to climate change and ecological factors to assess vulnerability. TVAs, as presented in this study, can easily be adapted to include extra drivers and species, and we would therefore recommend surveillance institutes to consider integrating these types of assessments for evaluating and improving surveillance for wildlife-borne disease emergence.

Figure 1

Adapted framework for the assessment of the impact of national climate change on mammals according to the IUCN methodology [11], additionally illustrating the link toward surveillance priorities for human and animal health risk. Mammals scoring high across all dimensions (exposure, sensitivity, and low adaptive capacity) are classified as highly vulnerable (1). Biologically susceptible mammals (2) are not exposed but have a high sensitivity and a low adaptive capacity. Potential adapters (3) are exposed and sensitive but have a high adaptive capacity, and potential persisters (4) are exposed and have a low adaptive capacity but have a low sensitivity to climate change [11]. Species not occurring in any of these four categories were classified as “exposed only” (5), “sensitive only” (6), “low adaptive capacity only” (7), or “low vulnerability” (low risk in all dimensions of vulnerability; 8) [11].

Figure 2

Extent of climate change in the Netherlands per 25 km². Areas in the Netherlands that are experiencing the highest degree of change between the baseline period (1961–1990) and the recent period (1991–2020) are shown in dark turquoise (SED ≥ 2.33), areas with a medium degree of change are displayed in turquoise (2.20 ≤ SED < 2.33), and regions with a low amount of change shown in light turquoise (SED < 2.20). Degree of change per included bioclimatic factor is shown in Figure S2.

Figure 3

Bioclimatic predictors of baseline and recent periods. BIO01, average monthly temperature in the baseline period versus in the recent period (confidence interval (CI) is displayed in gray). BIO05, the maximum temperature of the warmest month in the baseline period versus the recent period. BIO06, minimum temperature of the coldest month in the baseline period versus the recent period. BIO12, monthly precipitation in the baseline period versus the recent period (CI is displayed in gray). BIO13, precipitation in the wettest month in the baseline period versus the recent period. BIO14, precipitation in the driest month in the baseline period versus the recent period. Precipitation is measured in millimeters (mm), and temperature is expressed in degrees Celsius (°C).

Figure 4

The presence of species classed as highly vulnerable (Category 1) or as potential adapters (Category 3) per 25-square-kilometer block.

Figure 5

Number of carcasses of wild mammals per year (sampling year 2022 is incomplete) received by DHWC. The peak submission year was in 2014 (n = 256) (a). The relative records examined per mammalian order (b) and the geographical location from which the records originated (c). The location of the DWHC is indicated by the black star (c). The two locations of the category 1 species in the DWHC database were found 3.2 kilometers from each other and are together indicated by a diamond.

Figure 6

The number of species per order per vulnerability category (a) and the cumulative number of records per order within the DWHC database (b, Table S1).