Towards a better understanding of our land

Despite our daily interactions with land, we have an incomplete picture of the processes that shape the landscape and the consequences of our activities on land. This limits our ability to achieve the best outcomes for ourselves and the environment.

The ways we use and manage land are shaped by a complex interaction of demands and drivers, which can be economic, demographic, governance (local and global), technological, and cultural. Drivers do not operate in isolation but can influence and be influenced by each other (Nelson et al., 2006).

The world is on the threshold of the era of committed climate change. This is when the impacts of climate change have become irreversible within our lifetimes, regardless of any actions we may take.

We already have a good knowledge of the main drivers of land-use change in Aotearoa New Zealand. This includes climate change as an outcome of other drivers, and a driver in its own right.

More work is needed to quantify the relative contributions of drivers and how they interact with each other to shape land use. This includes understanding whether certain drivers are more or less important and if the importance of different drivers is changing over time. Climate change will amplify existing risks and create new risks for natural and human systems, so untangling the importance of different drivers as they affect land is paramount.

Models and scenarios can provide useful information about how a future climate may influence New Zealand’s land-based economy. Their analysis can reveal the likely directions of change and the implications of different options to adapt to the impacts of climate change. One example is how pasture productivity and commodity prices would be affected by different climate and economic scenarios (Ausseil et al., 2019a). Having tools to explore probable changes will become more and more important given accelerating complexity, interacting drivers, and an uncertain future (Banuri et al., 2019; Wu et al., 2017).

To manage land resources effectively, we need a good understanding of how actions translate to effects on the environment. Some aspects of this understanding are well developed. However, the environmental system is complex, and work is needed to understand the connections between the many processes that affect the land.

How intensive land use affects native land ecosystems has not been widely studied. We do not understand its impacts beyond the destruction of habitats when native vegetation is cleared. Monitoring for maintaining ecosystem processes, whether the ecosystem as a whole functions well, can help understand interactions between native and productive systems and drivers of biodiversity better (Bellingham et al., 2020; McGlone et al., 2020). Monitoring the environment on farms, including the biodiversity, could enhance nationwide monitoring and improve an understanding of the interactions between modified and native ecosystems.

Interactions between land, freshwater, the marine environment, air, atmosphere, and climate occur on different spatial and time scales. Where and when these interactions occur, and how they affect other domains is not well understood. For example, while the effects of intensive land use on water quality are known, the interactions between land, groundwater, rivers, lakes, and the ocean are not well understood.

Some major gaps remain including in what chemical form, and through which pathways nutrients like nitrogen and phosphorus travel through different types of soil into groundwater.

As reported in chapter 3 there are still indicators, crops, and land uses that do not have target ranges for soil quality (especially for cropping and horticultural land uses). We still cannot adequately correlate soil nitrogen target ranges to understand the impacts on freshwater quality. The soil quality indicators may not fully capture the environmental impacts of intensive land use on the wider environment. Also, the concept of soil quality focuses on its intended use rather than the broader concept of soil health. Soil health is a soil’s ongoing capacity to function as a living ecosystem that sustains plant, animal, and human health.

We also lack a full understanding of how soil health and biodiversity are affected by land use and intensification. A major knowledge gap in New Zealand and globally is understanding soil biodiversity, how it affects the quality of soil, and how ecosystems function (FAO et al., 2020; Hermans et al., 2020).

Demands on land, drivers of land use, management interventions, soil processes, and other factors influence land and the environment over different time scales. There is however, limited time series data to explore change over time.

How fast or slowly environmental processes change or react is often not well understood or taken into account. The legacy of previous land uses (like soil compaction or contamination) can have long-term effects on the ways we manage and use land today. Lag effects that show up several years or decades later, such as high levels of nitratenitrogen in groundwater, can be an unwelcome surprise.

Long-term monitoring can help to understand the effect of time on environmental processes, and enable us to track issues (PCE, 2019). Long-term studies can show how effects from outside (like climate change and socioeconomic drivers) affect the environmental system. These studies provide a better understanding of the system and how it adapts to change. Overseas, long-term ecological studies and trials have contributed to knowledge about how agricultural and natural ecosystems function, and how our actions affect the environment (Lindenmayer et al., 2012; Macdonald et al., 2020). More work on New Zealand-specific environments is needed.

Māori see the environmental system as indivisible from themselves and their culture. For hundreds of years, Māori have been kaitiaki (caretakers) of te taiao (the environment), building on generations of mātauranga (knowledge). The use of a te ao Māori (Māori world view) framework and mātauranga Māori is particularly helpful for understanding and addressing issues that affect several different parts of the environmental system.

We recognise the importance of land as a place to live and as a source of food, income, culture, and recreation, but knowledge gaps around how it contributes to our wellbeing remain. The health of the land and our wellbeing go hand-in-hand, so a better understanding of all the ways they are connected is critical for navigating the future.

Maintaining land for our wellbeing today is fundamental but at the same time, we must ensure it can provide for the wellbeing of future generations. According to the Parliamentary Commissioner for the Environment, “empirical research is required to provide evidence of the links between environmental quality and wellbeing” because “the extent to which natural resources can be safely depleted in pursuit of building up other desirable assets is at the heart of a long-standing debate about what sustainable development entails” (PCE, 2019).

Different aspects of our wellbeing are affected by the different ways we use land, but this also varies over space and through time. Understanding this complexity is essential for improved decision-making about how land is managed today and in the future.