Low Copper Levels Associated with Low Carcass Weight in Wild Red Deer ( Cervus elaphus ) in Norway

Variability of the Ionome of Wild Boar (Sus scrofa) and Red Deer (Cervus elaphus) in a Dutch National Park, with Implications for Biomonitoring

The ionome-an important expression of the physiological state of organisms-is poorly known for mammals. The focus on particular tissues-such as liver, kidney, and bones-in biomonitoring of environmental pollution and potential deficiencies is based on widely held assumptions rather than solid knowledge of full mammalian ionomes. We examined the full ionome of Red deer (Cervus elaphus) and Wild boar (Sus scrofa), two commonly used mammals for biomonitoring, in a Dutch protected nature reserve (Veluwezoom). We used four individuals per species. We dissected 13 tissues and organs from each individuals (eight in total) of each species and measured 22 elemental concentrations in each. We assessed, for each element, how concentrations varied across tissues within and between individuals. Based on existing literature, we put our findings in the context of their function in the mammalian body. We found that the ionome was highly variable between as well as within the two species. For most elements, tissues containing the highest and lowest concentration differed between individuals. No single tissue accurately represented the accumulation of toxic elements or potential deficiencies in the bodies. Our assessment of the element's biological roles revealed a serious lack of reference values. Our findings imply that analyses of commonly used tissues in biomonitoring do not necessarily capture bioaccumulation of toxins or potential deficiencies. We recommend establishing a centralized database of mammalian ionomes to derive reference values in future. To our knowledge, our study is one of the most complete assessments of mammalian ionomes to date.

Drivers of geophagy by red brocket deer (Mazama americana) at Amazonian interior forest mineral licks

Mineral licks are key ecological components of the Amazon rainforest, providing critical dietary functions for herbivorous and frugivorous mammals and birds, which help maintain the structure and function of the forest itself through seed and nutrient dispersal. One of the most frequent visitors of interior forest mineral licks in the Amazon is the red brocket deer (Mazama americana), a large-bodied ruminant frugivore and seed predator. While several hypotheses for the drivers of geophagy exist, including mineral supplementation, toxin adsorption, and habitat selection, robust data on geophagy for the red brocket deer for large numbers of mineral licks is nonexistent. We used soil data from 83 mineral licks in conjunction with camera trap data from 52 of those mineral licks and a mixed-effects modeling approach to test the three proposed hypotheses of geophagy for the red brocket deer. We found that consumed soils at mineral licks had elevated concentrations of almost all major and minor biologically active minerals measured, including Ca, Na, Mg, K, Cu, Zn, and Mn. Model results suggest that all three hypotheses hold true to some extent for the red brocket deer, with the greatest support for the mineral supplementation hypothesis, in particular with respect to Mg, Ca, Na, Cu, and Zn. This study provides critical information on the feeding ecology of the red brocket deer in the wild, and the first robust analysis of geophagy of an Amazonian mammal involving a large sample size of interior forest mineral licks.

Geochemical landscapes as drivers of trace and toxic element profiles in wild red deer (Cervus elaphus)

Tissue concentrations of essential trace and toxic elements in red deer (Cervus elaphus) are associated with the plants, soil and water they ingest. As such, variation in tissue concentrations is associated with variation in local geochemistry and bioavailability of elements. Physiological factors such as liver fluke (Fasciola hepatica) infection, breeding status, and in-tissue element interactions may also affect tissue concentrations, though their effects in red deer are not well understood. The primary objective of this study was therefore to survey wild red deer liver element concentrations across a range of geographically distinct populations during the Scottish red deer stalking season; and, in so doing, establishes element reference ranges while also exploring geographic and temporal variation and physiological factors. Livers were sampled from carcasses intended for human consumption on nine hunting estates during two seasons (2012-13, 2013-14). Samples were digested and analysed by ICP-OES for essential trace elements (Co, Cu, Fe, Mn, Mo, Se, Zn) and for Cd. Data (n=787) were modelled against cull location, date, and F. hepatica diagnosis. Interactions between elements within liver, and differences in element profiles between estates, were explored by principal component analysis. Our results revealed marked geographic variation in Cd, Cu and Se, where up to four-fold differences in median element concentrations occurred between estates, and, in males, Mn, Mo and Zn declined as the breeding season approached. In both sexes, within-liver associations (Cd-Cu-Se and Mn-Mo-Zn) were found. In females, liver Zn was greater on average in individuals that were not infected with F. hepatica. This study is the first to quantify geographic variation in Scottish red deer liver element concentrations; the drivers of which remain to be explored (and may be management related), and, the consequence of which may affect sub-clinical health.