Periodic Reporting for period 1 - RE-NOURISH (Nutrient redistribution by mammals as a key mechanism for ecosystem restoration)
Reporting period: 2023-02-01 to 2025-01-31
It is increasingly acknowledged that animals can reshape the chemistry of their environments. Through the consumption, assimilation, transportation and excretion of different elements, animals redistribute elements - including carbon, nitrogen, phosphorus and sodium - across Earth’s surface. By liberating nutrients and connecting ecosystems, diverse animal communities can help increase the overall fertility of their ecosystems.
However, what is less understood is how different wildlife management actions may influence this vital ecosystem service provided by animals. For example, what effect does predator management have for overall chemical heterogeneity through the creation of animal carcasses and nutrient hotspots? How does the nutrient landscape change if hunting or wildlife reintroduction scenarios are enacted?
Understanding how these different human activities alter animal-nutrient movement has broad implications. Most large animal populations are – to some degree – managed by people. Moreover, we are currently in the UN Decade of Ecosystem Restoration, where there is a specific emphasis on restoring ecosystems globally. It is therefore vital to ensure that wildlife management actions act synergistically with ‘natural’ animal ecosystem functions towards biodiversity and restoration goals. While challenging, such efforts are an important step towards better ecosystem management.
However, what is less understood is how different wildlife management actions may influence this vital ecosystem service provided by animals. For example, what effect does predator management have for overall chemical heterogeneity through the creation of animal carcasses and nutrient hotspots? How does the nutrient landscape change if hunting or wildlife reintroduction scenarios are enacted?
Understanding how these different human activities alter animal-nutrient movement has broad implications. Most large animal populations are – to some degree – managed by people. Moreover, we are currently in the UN Decade of Ecosystem Restoration, where there is a specific emphasis on restoring ecosystems globally. It is therefore vital to ensure that wildlife management actions act synergistically with ‘natural’ animal ecosystem functions towards biodiversity and restoration goals. While challenging, such efforts are an important step towards better ecosystem management.
The primary objective of RENOURISH was to quantify how different wildlife management actions alter the chemistry of diverse landscapes, from tropical forests to European temperate forests. This was achieved principally through the development and validation of a generalisable computer model, where animals can roam landscapes, consuming and egesting various chemical elements. By carefully parameterising important animal traits (e.g. movement patterns and reproduction rates), this model could then determine which species were particularly important for modifying landscape chemistry. Wildlife management actions, such as animal reintroduction or off-site removal programmes were then enacted on top of the base model to understand how such actions impact the fertility and chemical heterogeneity of the landscape.
The model was first validated in two locations; Kruger National Park, South Africa and the Amazon Basin in South America. These landscapes contain diverse animal communities, from which it was possible to determine which functional traits (e.g. body size, diet) were most important for animal nutrient redistribution. Resulting patterns in landscape chemistry were then compared to in-situ local field data.
The model was then applied to diverse wildlife management scenarios. Simulations in Kruger National Park highlighted that large animals were particularly important for long-distance nutrient transport, but other animal characteristics (e.g. diet) could influence local patterns. In the Amazon rainforest, human communities have settled close to rivers for accessibility. However, extensive bushmeat hunting in these landscapes have severed animal nutrient arteries from from the nutrient-rich floodplain to nutrient-poor uplands. In the Bavarian Forest National Park, Germany, recent lynx and wolf reintroductions have (to some degree reduced the need for ungulate culling), thereby increasing the annual number of carcasses returned to the land and increased overall nutrient heterogeneity.
The model was first validated in two locations; Kruger National Park, South Africa and the Amazon Basin in South America. These landscapes contain diverse animal communities, from which it was possible to determine which functional traits (e.g. body size, diet) were most important for animal nutrient redistribution. Resulting patterns in landscape chemistry were then compared to in-situ local field data.
The model was then applied to diverse wildlife management scenarios. Simulations in Kruger National Park highlighted that large animals were particularly important for long-distance nutrient transport, but other animal characteristics (e.g. diet) could influence local patterns. In the Amazon rainforest, human communities have settled close to rivers for accessibility. However, extensive bushmeat hunting in these landscapes have severed animal nutrient arteries from from the nutrient-rich floodplain to nutrient-poor uplands. In the Bavarian Forest National Park, Germany, recent lynx and wolf reintroductions have (to some degree reduced the need for ungulate culling), thereby increasing the annual number of carcasses returned to the land and increased overall nutrient heterogeneity.
Empirical datasets generated and collated by RENOURISH have allowed for much improved parameterisation of key animal characteristics used to estimate animal nutrient transport. For example, detailed information on element-specific gut passage time has helped identify which animal groups are important for long-distance transport.
Previous modelling attempts have been necessarily forced to estimate animal nutrient redistribution using an “average” animal and the absence of interactions. By modelling at the individual-level, the transformational agent-based model developed in RENOURISH now incorporates many fundamental biological processes, including: growth, maturity, reproduction and death. Interactions between individual animals, population densities and their environment constrain how these biological processes operate, making for significant improvements in ecological realism.
A key aspect of RENOURISH has been to expand the suite of elements considered important. Previously, most research effort has focused on the major limiting nutrients: nitrogen and phosphorus. In this project, we have additionally examined how sodium – an essential nutrient for animals to thrive – is redistributed by wildlife communities.
The agent-based model developed through RENOURISH is now available for further development. Indeed, a number of MSc and PhD students are already making improvements to this model and using it for novel research questions (e.g. how do birds redistribute nutrients from supplementary bird feeding stations?). As the user community grows, it is hoped that the model will continue to improve and feedback key information for stakeholders and wildlife managers.
Previous modelling attempts have been necessarily forced to estimate animal nutrient redistribution using an “average” animal and the absence of interactions. By modelling at the individual-level, the transformational agent-based model developed in RENOURISH now incorporates many fundamental biological processes, including: growth, maturity, reproduction and death. Interactions between individual animals, population densities and their environment constrain how these biological processes operate, making for significant improvements in ecological realism.
A key aspect of RENOURISH has been to expand the suite of elements considered important. Previously, most research effort has focused on the major limiting nutrients: nitrogen and phosphorus. In this project, we have additionally examined how sodium – an essential nutrient for animals to thrive – is redistributed by wildlife communities.
The agent-based model developed through RENOURISH is now available for further development. Indeed, a number of MSc and PhD students are already making improvements to this model and using it for novel research questions (e.g. how do birds redistribute nutrients from supplementary bird feeding stations?). As the user community grows, it is hoped that the model will continue to improve and feedback key information for stakeholders and wildlife managers.