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Climate change will have far-reaching negative impacts on all aspects of Earth's state and functions, including ongoing biodiversity decline and threats to agricultural production. These effects will be dependent on geographic location; for example, parts of New Zealand are predicted to have increased flooding, drought and wildfires, depending on the local environmental context. Effects of climate change on agricultural production will be both direct, such as crop losses due to flooding, and indirect, such as increased invasive pest insect and weed pressure on horticultural production or decline in water capture capacity in pastoral South Island High Country tussock grasslands due to increased fire frequency combined with grazing. It is crucial to understand the complex, interactive effects of climate change on agroecosystems, mediated by biodiversity, if human interventions, such as land management, are to be developed and effectively applied to mitigate negative consequences. Even better is if those interventions can be used to address the biodiversity crisis. Nature-based Solutions is a framework that offers such solutions; however, improved scientific understanding of these interacting processes within agroecosystems is required at multiple temporal and spatial scales to justify sector investment for changes in agricultural land management practices that enhance production and native biodiversity. [ABSTRACT FROM AUTHOR]

Globally, treeline ecotones vary from abrupt lines to extended zones of increasingly small, stunted and/or dispersed trees. These spatial patterns contain information about the processes that control treeline dynamics. Describing these patterns consistently along ecologically meaningful dimensions is needed for generalizing hypotheses and knowledge about controlling processes and expected treeline shifts globally. However, existing spatial categorizations of treelines are very loosely defined, leading to ambiguities in their use and interpretation. To help better understand treeline‐forming processes, we present a new framework for describing alpine treeline ecotones, focusing on hillside‐scale patterns, using pattern dimensions with distinct indicative values: 1) the spatial pattern in the x‐y plane: a) decline in tree cover, and b) change in the level of clustering. Variation along these dimensions results in more or less 'discrete' or 'diffuse' treelines with or without islands. These patterns mainly indicate demographic processes: establishment and mortality. 2) Changes in tree stature: a) decline in tree height, and b) change in tree shape. Variation along these dimensions results in more or less 'abrupt' or 'gradual' treelines with or without the formation of environmental krummholz. These patterns mainly indicate growth and dieback processes. Additionally, tree population structure can help distinguish alternative hypotheses about pattern formation, while analysing the functional composition of the ecotonal vegetation is essential to understand community‐level processes, controlled by species‐specific demographic processes. Our graphical representation of this framework can be used to place any treeline pattern in the proposed multi‐dimensional space to guide hypotheses on underlying processes and associated dynamics. To quantify the dimensions and facilitate comparative research, we advocate a joint effort in gathering and analysing spatial patterns from treelines globally. The improved recognition of treeline patterns should allow more effective comparative research and monitoring and advance our understanding of treeline‐forming processes and vegetation dynamics in response to climate warming. [ABSTRACT FROM AUTHOR]

Flammability is an important plant trait, relevant to plant function, wildfire behaviour and plant evolution. However, systematic comparison of plant flammability across ecosystems has proved difficult because of varying methodologies and assessment of different fuels comprising different plant parts. We compared the flammability of plant species at the leaf‐level (most commonly used in flammability studies) and shoot‐level (which retains aspects of plant architecture). Furthermore, we examined relationships between leaf functional traits and flammability to identify key leaf traits determining shoot‐level flammability.We collated and analysed existing leaf‐ and shoot‐level flammability data from 43 common indigenous perennial New Zealand plant species, along with existing data on leaf morphological and chemical traits.Shoot‐level flammability was decoupled from leaf‐level flammability. Moreover, leaf‐level rankings of flammability were not correlated with rankings of flammability of plants derived from expert opinion based on field observations, while shoot‐level rankings had a significant positive relationship. Shoot‐level flammability was positively correlated with leaf dry matter content (LDMC), phenolics and lignin, and negatively correlated with leaf thickness.Synthesis. Our study suggests that shoot‐level measurements of flammability are a useful and easily replicable way of characterizing the flammability of plants, particularly canopy flammability. With many parts of the world becoming more fire‐prone, due to anthropogenic activities, such as land‐use change and global warming, this finding will help forest and fire managers to make informed decisions about fuel management, and improve modelling of fire‐vegetation‐climate feedbacks under global climate change. Additionally, we identified some key, widely measured leaf traits, such as leaf dry matter content (LDMC), that may be useful surrogates for plant flammability in global dynamic vegetation models. [ABSTRACT FROM AUTHOR]

Aim: Identifying suitable areas for invasive species establishment is of critical importance for their early detection and rapid eradication. However, our ability to detect suitable areas is impeded by the tendency of species to shift their niche postinvasion. In this study, we (a) investigate the frequency of niche shift within invasive freshwater invertebrates and (b) use niche conservatism information to prioritize potential hotspots of invasion for non‐native freshwater invertebrates in New Zealand. Location: Global occurrence data and predictions over New Zealand. Methods: We characterized the native and invasive realized niche using occurrence data for 22 invasive freshwater invertebrates in relation to 27 derived climate variables. Using principal component analysis and species distribution models, we measured the degree of niche shift for each species and identified hotspots of invasion and niche conservatism described within biogeographic units in New Zealand. Results: Niche shift was detected frequently among the invasive freshwater invertebrates studied here, where 90% showed a significant niche change. The characterization of the species niche enabled the identification of species whose management might be hampered because of their ability to colonize novel environments. Locations covering more than half of the land area of New Zealand were found to be climatically suitable for at least four and up to 11 species. Areas that were found to be climatically suitable for several species but were not identified as hotspots of niche conservatism could be considered less critical for surveillance and monitoring. Main conclusions: Aquatic invertebrates show a high degree of niche shift. By combining climate suitability predictions and niche conservatism, we were able to prioritize invasion areas. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim The network structure of food webs plays an important role in the maintenance of diversity and ecosystem functioning in ecological communities. Previous research has found that ecosystem size, resource availability, assembly history and biotic interactions can potentially drive food web structure. However, the relative influence of climatic variables that drive broad-scale biogeographic patterns of species richness and composition has not been explored for food web structure. In this study, we assess the influence of broad-scale climatic variables in addition to known drivers of food web structure on replicate observations of a single aquatic food web, sampled from the leaves of the pitcher plant ( Sarracenia purpurea), at different geographic sites across a broad latitudinal and climatic range. Location Using standardized sampling methods, we conducted an extensive 'snapshot' survey of 780 replicated aquatic food webs collected from the leaves of the pitcher plant S. purpurea at 39 sites from northern Florida to Newfoundland and westward to eastern British Columbia. Methods We examined correlations of 15 measures of food web structure at the pitcher and site scales with geographic variation in temperature and precipitation, concentrations of nutrients from atmospheric nitrogen deposition, resource availability, ecosystem size and the abundance of the pitcher plant mosquito ( Wyeomyia smithii), a potential keystone species. Results At the scale of a single pitcher plant leaf, linkage density, species richness, measures of chain length and the proportion of omnivores in a web all increased with pitcher volume. Linkage density and species richness were greater at high-latitude sites, which experience low mean temperatures and precipitation and high annual variation in both of these variables. At the site scale, variation in 8 of the 15 food web metrics decreased at higher latitudes, and variation in measures of chain length increased with the abundance of mosquitoes. Main conclusions Ecosystem size and climatic variables related to latitude were most strongly correlated with network structure of the Sarracenia food web. However, in spite of large sample sizes, thorough standardized sampling and the large geographic extent of the survey, even the best-fitting models explained less than 40% of the variation in food web structure. In contrast to biogeographic patterns of species richness, food web structure was largely independent of broad-scale climatic variables. The large proportion of unexplained variance in our analyses suggests that stochastic assembly may be an important determinant of local food web structure. [ABSTRACT FROM AUTHOR]