Identifying the causes of biodiversity change with specific references to the Intergovernmental Science-policy Platform on Biodiversity and Ecosystem Services drivers

Challenges

Biodiversity loss is the result of human activity and the overuse of natural capital. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) recognises this as the main driver of the loss of biodiversity and decline in ecosystem service supply. However, the IPBES categorises it as an indirect driver of biodiversity loss as it acts through five direct drivers of loss: land use change, climate change, pollution, invasive species and direct exploitation. These drivers have been shown to have a wide-scale impact on biodiversity.

Agriculture is a significant contributor to the global decline in biodiversity, directly through land use change and environmental impacts but also indirectly through climate change. In the arable sector, neither alternative approaches to conventional agriculture nor legislation has proved effective in mitigating these adverse effects. Much has been written about insect declines, but the evidence is contested and is generally poorly linked to explanatory drivers. Aphids are a widespread and often abundant component of insect communities. Due to their biology and life cycle, they provide an excellent indicator of local environmental conditions.

One of the biggest predicted climatic drivers of change for Scotland is drought. There is a particular urgency in understanding the responses of forest systems given the decadal periods required for the growth of trees to maturity; trees established now will likely experience significant climate changes as they grow to maturity. This is a particularly important research need for a species such as Scots pine, with its wide genetic variability even within its Scottish native populations. 

Salmon populations are also in decline, with climate and land use change identified as potential drivers. However, pollution and in particular exposure to chemical contaminants may be contributing to this decline. Although many of these chemicals may be present in waters at sub-lethal concentrations. Endocrine Disrupting Compounds alter hormone systems and affect reproductive development and function in aquatic animals (such as salmon), with consequent impacts at the population level.

Another key global driver of biodiversity loss is the invasion of non-native species. They can seriously impact individual species and have ecosystem-level consequences. Current risk assessment approaches to invasive non-native species do not allow generic assessments to be developed, nor consider the wider socioeconomic aspects of invasive non-native species. Risk assessments are currently done at the level of an individual plant pest or pathogen.

Questions

Solutions

This project aims to identify how the "IPBES drivers" affect key parts of Scotland’s biodiversity. It focuses on:

• The ecosystem level, in terms of understanding how climate change is affecting system resilience and how systems can be managed to improve resilience.
• The habitat level to understand how climate change or invasive species can affect important habitats.
• The species level, in terms of understanding which drivers are resulting in changes in species abundances.

Building resilience and sustainable land use

Scotland’s landscapes are cultural, the results of millennia of interactions between biodiversity and human use. In upland areas, where almost all of Scotland’s semi-natural habitats occur, we need to identify management options that protect biodiversity and build resilience for future environmental change. In contrast, past land use change has driven biodiversity in the lowlands to the edges and agri-environment schemes have aimed at reversing these trends. We will investigate how increasing the scale of management intervention can reverse these trends and increase the resilience of lowland biodiversity.

Climate change, pollution and land use change have both direct and indirect impacts on biodiversity. Species abundances and ranges might be directly affected by temperature, nitrogen toxicity or reduced or increased land use intensity. However, the former two drivers could have indirect impacts, for example, increased productivity coupled with reduced grazing would lead to shading out of low-growing plant species and increased fuel load for wildfires; this project will take the novel step of identifying these indirect impacts. We need to work across multiple drivers to understand biodiversity loss and identify sustainable management strategies to adapt to global change and so the project will provide advice to land managers on strategies to mitigate global change impacts on grazed ecosystems.

Agriculture is a significant contributor to the global decline in biodiversity, directly through land use change and environmental impacts but also indirectly through climate change. In the arable sector, neither alternative approaches to conventional agriculture (e.g., organic or integrated farming) nor legislation has proved effective in mitigating these adverse effects. In England, Famer Clusters are becoming a popular approach in which farmers work collectively at the landscape scale to tackle shared concerns. We will investigate the potential of the approach to reverse biodiversity loss by improving farmland management at landscape scales.

Apportioning biodiversity change to different drivers 

For the first time, we are analysing trends for Scotland in aphid species abundance, composition, and diversity concerning land use, pollution (pesticides) and climate. This is showing where drivers act individually or in concert to affect the abundance of specific taxa or groups of species and could highlight taxa acting as indicators of change. We are also using a unique experimental platform, a “sapling bank” of native Scots pine with several hundred individuals of known provenance to assess drought impacts on the Caledonian pine forest, a nationally important habitat. We are also assessing how Endocrine Disrupting Compounds are distributed in aquatic systems, quantifying how they bio-magnify through the food chain and bio-accumulate in salmon and assessing their impacts on biodiversity and commercial interests.

The effects of invasive and non-native species, pests, and pathogens on ecosystems

We are identifying potential invasive species, their management and linkages between biodiversity impacts and socio-economic consequences to improve proactive management of Invasive Non-Native Species (INNS) across Scotland. This research exploits novel approaches to the use of environmental DNA to catalogue biodiversity via metabarcoding and use it to discover microbial plant pathogens that threaten biodiversity. This is the first time there has been an exploration of a broad range of oomycete INNS, such as Phytophthora, to better understand their biodiversity, spread and impact on plant health in key Scottish environments. We are developing a risk assessment approach for non-native plant pests and pathogens that identifies habitats at greatest risk because of a lack of functional redundancy, a novel approach to risk assessments. We are improving our understanding of the socio-economic implications of the establishment and spread of INNS in Scotland by collating existing cost data and building on this through the addition of expert consultation. The outputs include a framework for determining the biological, social, and economic implications of the establishment and spread of INNS.