Mediterranean Eucalyptus plantations affect small mammal ectoparasites abundance but not individual body condition

Abstract

Biodiversity is recognizably affected by land conversion for agriculture. However, the assessment of impacts on wildlife often lacks information on populations structure and individuals' condition, allowing only a limited view of the problem. Individual body condition/health can influence animal's reproductive success or survival. Eucalyptus globulus plantations are important forestry systems in Iberia, being the widest forested‐land use in Portugal, which hosts the broadest European E. globulus coverage. We tested Eucalyptus plantations' effects on small mammals' body condition (using the Scaled Mass Index‐SMI as surrogate) and ectoparasite abundance (number of mites, ticks and fleas per host). We applied a Generalized Linear Mixed Model (GLMM) approach for testing the influence of gender, habitat, species, season and understory cover on SMI and ectoparasites abundance. We captured 681 individuals, hosting overall 521 fleas (n = 305), mites (n = 159) and ticks (n = 57). Animal's body condition was not affected by plantations, but was lower for males and higher in spring. However, animals captured in Eucalyptus plantations and spring had higher parasite abundance (namely ticks and fleas), as well as males. Mites results were inconclusive. Body condition patterns seem to be determined by males demanding spatial/reproductive behavior (i.e., wider home‐ranges and search for females), while plantations promote ectoparasites abundance (e.g., induced by habitat disturbance and dilution effect). Results highlight that plantations may have negative effects on wildlife, but the evaluation of anthropic landscapes impact upon wildlife should encompass several bio‐ecological indicators, since the use of a restricted set (e.g., body condition) may induce a biased view.

Riparian Vegetation Conversion to an Oil Tea Plantation: Impacts on Small Mammals at the Community, Population, and Individual Level

“…As predicted by epidemiological models, a high host density increases the likelihood of parasite infection [58,59]. Although there were fewer A. agrarius individuals in the Camellia forest than the flood-meadow, the ectoparasite load was greater in the Camellia forest, possibly due to habitat anthropogenizationt, which is known to promote the presence and density of parasites [30,60]. Notably, during the rainy season, the floodmeadow is submerged, and small mammals such as A. agrarius will migrate to surrounding habitats.…”

“…Our study assessed the effect of an oil tea plantation on small mammals at three levels: (1) community level, evaluating diversity, and composition; (2) population level, assessing density, and sex ratio; and (3) individual level, examining body condition index, and ectoparasite load. As oil tea plantations are a monoculture in our study area, we predict that the conversion of natural habitats to Camellia forests could result in low community diversity and population density because of the absence of habitat diversity and complexity [29], and poor body condition due to ecosystems simplification and anthropic disturbance [24,30]. Our findings hold significant implications for riparian vegetation restoration and management, given the critical role of small mammals in ecosystems.…”

Host sweet host: Rodent communities support similar ectoparasite diversity regardless of anthropogenic disturbance

“…In general, the prevalence of ectoparasites on rodents in disturbed areas (e.g., in cities and agricultural lands) has been reported to range between 23% and 89% (Baak‐Baak et al., 2018; Hamidi et al., 2015; Herrero‐Cófreces et al., 2021; Moravvej et al., 2016; Teixeira et al., 2019), while in undisturbed areas (e.g., protected areas) this ranges between 57% and 98% (Bohn et al., 2017; Fantozzi et al., 2022; Kiffner et al., 2011; Thanee et al., 2009). Several studies have compared ectoparasite prevalence between disturbed and undisturbed sites in the same areas (Durden et al., 2004; Kiene et al., 2020; Smith et al., 2021; Veloso‐Frías et al., 2019).…”

Determinants of Small Mammals’ Body Condition in Eucalyptus Dominated Landscapes

“…Several studies have reported that Eucalyptus exotic plantations impose varying taxa and landscape-specific impacts on native wildlife (e.g., changes in activity and occupancy patterns, modification of interspecific relationships, and increase in parasites' prevalence; [9][10][11][12]), leading to changes in communities' composition (e.g., simplification of predator communities; [13]), thus inducing conservation concerns (e.g., [14,15]). This forestry system management affects the diversity and abundance of native understory [7], which is one of the most influential factors supporting biodiversity in forestry plantations.…”

“…Despite the large cover of Eucalyptus plantations in Europe (covering almost 1.5 million ha; [25]), few studies have assessed how these landscapes affect wildlife health/fitness (i.e., body condition), particularly in small mammals, whose condition will affect upper trophic levels within the community, e.g., [26]. Additionally, the available data are from local-scale studies (e.g., only one study area), and often did not present conclusive results regarding the effect of plantations on small mammals' body condition [12,17]. Small mammals are responsible for some fundamental ecosystem functions such as soil aeration and seed dispersal [27].…”