Deer management has become an integral part of ecosystem recovery efforts across the globe. Within Scotland, annual deer culls have been implemented to control deer browsing, with the carcasses most often removed from the landscape. Given that animal bodies concentrate large quantities of nutrients, this practice may deplete ecosystems of vital nutrients. We quantified the nitrogen, phosphorous and calcium losses from the removal of culled deer carcasses using nationwide statutory cull reports for four deer species in Scotland between 2010 and 2021. We estimate that annual losses from carcass removal over this period averaged 195,652 kg of nitrogen, 152,834 kg of phosphorus and 251,188 kg of calcium across Scotland. While both red and roe deer were culled at a much higher rate than the other two species red deer culls accounted for approximately 70% of the nutrients lost. Further, while large quantities of all three nutrients were removed from the landscape, calcium losses were particularly high. We then calculated nutrient losses within the three land classifications used in statutory cull reporting-agricultural areas, open range and woodlands-across Scotland's Deer Count Areas. Using data from the literature, we considered these losses in the context of other major environmental inputs and outputs within each land classification. Our results demonstrate that while open range lost more nutrients compared to the other two land classifications, culling resulted in high rates of phosphorus and calcium loss throughout all land classifications when compared to other environmental inputs. Practical implication. Our findings suggest that current practices of carcass removal are gradually stripping nutrients from the Scottish landscape, potentially undermining habitat recovery goals. While this study offers a preliminary, coarse scale summary of the issue, the way forward requires further study of local effects from carcass removal on nutrient pools and balancing deer management with habitat function through interwoven deer and nutrient management strategies. We quantified the nitrogen, phosphorous and calcium losses from the removal of culled deer carcasses using nationwide statutory cull reports for four deer species in Scotland between 2010 and 2021. Our findings suggest that current practices of carcass removal are gradually stripping nutrients from the landscape, potentially undermining habitat recovery goals.image
The ascent of water from the soil to the leaves of vascular plants, described by the study of plant hydraulics, regulates ecosystem responses to environmental forcing and recovery from stress periods. Several approaches to model plant hydraulics have been proposed. In this study, we introduce four different versions of plant hydraulics representations in the terrestrial biosphere model T&C to understand the significance of plant hydraulics to ecosystem functioning. We tested representations of plant hydraulics, investigating plant water capacitance, and long-term xylem damages following drought. The four models we tested were a combination of representations including or neglecting capacitance and including or neglecting xylem damage legacies. Using the models at six case studies spanning semiarid to tropical ecosystems, we quantify how plant xylem flow, plant water storage and long-term xylem damage can modulate overall water and carbon dynamics across multiple time scales. We show that as drought develops, models with plant hydraulics predict a slower onset of plant water stress, and a diurnal variability of water and carbon fluxes closer to observations. Plant water storage was found to be particularly important for the diurnal dynamics of water and carbon fluxes, with models that include plant water capacitance yielding better results. Models including permanent damage to conducting plant tissues show an additional significant drought legacy effect, limiting plant productivity during the recovery phase following major droughts. However, when considering ecosystem responses to the observed climate variability, plant hydraulic modules alone cannot significantly improve the overall model performance, even though they reproduce more realistic water and carbon dynamics. This opens new avenues for model development, explicitly linking plant hydraulics with additional ecosystem processes, such as plant phenology and improved carbon allocation algorithms.