Shrub encroachment into grassland ecosystems has been increasingly observed and documented worldwide in recent years. A grass–shrub transition can affect the diversity, abundance and functional integrity of grassland plant communities and understanding the drivers behind these processes is therefore crucial. While potential environmental drivers are often investigated, the role of spatial patterns of neighbouring shrub density in local shrub encroachment has been less well studied. The aim of this study is to investigate the relative role of neighbouring shrub density and topography as potential key drivers of shrub encroachment in a typical montane grassland ecosystem in New Zealand. We used the SPOT (Satellite Pour l’Observation) 6/7 multispectral imagery captured on one day in 2013 and in 2017 to calculate recent changes in shrub/grass cover during this period. Using the Normalised Difference Vegetation Index (NDVI), we classified the study area into grassland and shrubland and quantified the extent and change in these two land-cover types over the study period. We then investigated the relationships between changes in land cover and neighbourhood shrub density, elevation and aspect. Between 2013 and 2017, there was an overall shrubland increase of + 0.35

Past climate changes have had large impacts on modern ecological patterns. Understanding if legacies are distinguishable in the climatic niches of extant and locally extinct taxa can provide insight into the importance of climate in extinction events. To better understand mid- to late-Cenozoic New Zealand plant extinctions, which are often attributed to Cenozoic climate cooling, we identify 13 con-familial extinct and extant New Zealand genus pairs, which have modern distributions in Australia. Using climatic niches derived from current geographic distributions in Australia, we compared (i) total niche breadth, (ii) niche overlap, and (iii) individual climate parameters, to investigate potential climate drivers of intrafamilial extinction and persistence patterns in New Zealand. A majority of New Zealand extinct genera (9 out of 13 pairs) do not indicate climate niche legacies consistent with susceptibility to extinction from changing climates, while the remaining four extinct/extant pairs show slight climatic niche legacies. Three extinct genera have warmer niches than their extant counterpart, which is consistent with extinction reflecting intolerance of cooling Cenozoic climates. The other genus pair with a climatic niche legacy has an extinct genus that is distinguished by a niche with smaller precipitation seasonality than its extant counterpart, suggesting that climate metrics other than temperature may also be important extinction drivers in some taxa. Our results show that the mechanisms of Cenozoic extinctions of New Zealand genera are likely more complex than taxa reaching environmental tolerances due to cooling climates. Comparisons of current climatic niches between extant and extinct sister taxa can provide useful insights into large-scale, long-term climatic legacies but more analyses, including trait and phylogeographic patterns, would lead to additional insights into alternative pathways of extinction.

Our primary aim was to assess the hypothesis that distinctive features of the patterns of vegetation change during successive Quaternary glacial-interglacial cycles reflect climatic differences arising from forcing differences. We addressed this hypothesis using 207 half-degree resolution global biome pattern simulations, for time slices between 800 and 2 ka, made using the LPJ-GUESS dynamic global vegetation model. Simulations were driven using ice-core atmospheric CO2 concentrations, Earth's obliquity, and outputs from a pre-industrial and 206 palaeoclimate experiments; four additional simulations were driven using projected future CO2 concentrations. Climate experiments were run using HadCM3. Using a rule-based approach, above-ground biomass and leaf area index of LPJ-GUESS plant functional types were used to infer each grid cell's biome. The hypothesis is supported by the palaeobiome simulations. To enable comparisons with the climatic forcing, multivariate analyses were performed of global vegetation pattern dissimilarities between simulations. Results showed generally similar responses to glacial-interglacial climatic variations during each cycle, although no two interglacials or glacials had identical biome patterns. Atmospheric CO2 concentration was the strongest driver of the dissimilarity patterns. Dissimilarities relative to the time slice with the lowest atmospheric CO2 concentration show the log-linear relationship to atmospheric CO2 concentration expected of an index of ecocarbon sensitivity. For each simulation, extent and total above-ground biomass of each biome were calculated globally and for three longitudinal segments corresponding to the major continental regions. Mean and minimum past extents of forest biomes, notably Temperate Summergreen Forest, in the three major continental regions strongly parallel relative tree diversities, hence supporting the hypothesis that past biome extents played an important role in determining present diversity. Albeit that they reflect the climatic consequences only of the faster Earth system components, simulated potential future biome patterns are unlike any during the past 800 ky, and likely will continue to change markedly for millennia if projected CO2 concentrations are realised.

Grasslands in mountainous areas often show distinct responses in the timing of their growing season in relation to topographical variation. However, it is unclear which factors of topography (elevation, aspect, and slope) affect which phases of the timing in seasonal growth (start, peak, end, length of growing season). Here we investigated these relationships between topography and growing season timing in the three key grassland types in mountainous areas in South Island, New Zealand. From a near-daily NDVI (Normalized Difference Vegetation Index) dataset over a 16 year period (2001–2016), we extracted five annual land surface phenology indices: start, end, length, peak of the growing season and peak NDVI. Averages in these phenology indices were correlated with three topographical factors. The start of growing season occurred later by 7.1, 5.2 and 3.5 days per 100 m elevation in the three grassland types (Alpine, Tall Tussock and Low Producing grasslands). The end of the season occurred earlier by 1.8, 1.6 days and later by 0.4 days per 10-degree more south-facing (colder) aspects in the three grasslands. A longer growing season was observed at lower elevation and on north-facing (sunny) slopes in alpine grasslands. A later season peak occurred at higher elevation and on north-facing slopes in alpine grasslands and at higher elevations and on steeper slopes in non-alpine grasslands. Higher peak NDVI was detected at the lower elevation. Our results show that different facets of a landscape's topography affect different stages of a grassland's growing season, and these responses also differ between grassland types. This highlights the importance of considering all topographical features when relationships between the physical environment and biological responses are investigated.

Context: It is important to understand the responses of alpine vegetation to recent anthropogenic climate change. The mountainous landscapes with high climatic heterogeneity are good locations to investigate the effects of microclimatic variation on alpine ecosystems. Objectives: a) To what degree do topographical factors (aspect and elevation) affect the timing of growing season in alpine grasslands? b) Are these topographical effects different on alpine and non-alpine grasslands? Methods: We extracted five annual growth phenology indices (Start, End, Length, Peak and Peak-NDVI) in alpine and non-alpine grasslands in the Clutha river catchment, New Zealand with a near-daily NDVI (Normalized Difference Vegetation Index) dataset through 16 years (2001-2016). The shifting rates of these phenology indices were quantified with two topographical factors (aspect and elevation). Results: The start of season was delayed by 7.5, 5.1 and 3.7 days per 100 m higher of elevation in three grassland types (Alpine, Tall Tussock and Low Producing) respectively, and the end of season was advanced by 1.7, 1.3 days and delayed by 0.3 days per 10-degree-south on slopes individually. The longer season length was observed at lower elevation and on north-facing (sunny) slopes. The later season peak occurred at higher elevation and on north-facing slopes. The lower peak NDVI was detected at the higher elevation. Conclusions: In the studied grasslands, aspect and elevation were correlated to different phenological indices, and they affect phenology independently. The topographical effects are more pronounced in alpine ecosystems at the elevation above 1,300 m than in non-alpine ecosystems at lower elevation.

We investigate the temporal dynamics of shifts in phenological responses of a range of key stages of the growing season in New Zealand’s three indigenous grassland types over the last 16 years (2001–2016). A near-daily Normalized Difference Vegetation Index (NDVI) time series from MODerate Resolution Imaging Spectroradiometer (MODIS) was used to extract five annual growth phenology indices, namely the Start, End, Length, Peak and Peak NDVI of a growing season. The start of the growing season advanced (i.e. happened earlier) by a median of 7.2, 6.0 and 8.8 days per decade in Alpine, Tall Tussock and Low Producing grassland, whereas the end of the season advanced by a median of 4.5, 0.4 and 0.4 days in the three types respectively. The length of growing season was extended by 3.2, 5.2 and 7.1 days per decade in these three grassland types. Over 86% of the investigated grassland areas showed an advancing (earlier) start of the growing season, and 74% of Alpine grassland showed a trend toward an earlier end of season. Over 63% of all grassland types showed an increase in growing season length. A trend toward earlier growing season peak and overall increasing NDVI in the three grassland types indicate a tendency for increasing vegetation vitality in grassland ecosystems in recent years. The start of growing season was correlated with atmospheric pressure (negatively) and precipitation (positively) changes in winter–spring months, while the timing of the season end is positively correlated with air temperature and solar radiation in summer–autumn months. Our study shows that different grassland types differ in magnitude – but not in direction – of their recent shifts in timing of key growing season stages with high-alpine grasslands showing the strongest response. This study highlights the usefulness of remote sensing for monitoring ecosystem-level phenological shifts over large areas and long time periods.

Aim Recent studies in southern Africa identified past biome stability as an important predictor of biodiversity. We aimed to assess the extent to which past biome stability predicts present global biodiversity patterns, and the extent to which projected climatic changes may lead to eventual biome changes in areas with constant past biome. Location Global. Taxon Spermatophyta; terrestrial vertebrates. Methods Biome constancy was assessed and mapped using results from 89 dynamic global vegetation model simulations, driven by outputs of palaeoclimate experiments spanning the past 140 ka. We tested the hypothesis that terrestrial vertebrate diversity is predicted by biome constancy. We also simulated potential future vegetation, and hence potential future biome patterns, and quantified and mapped the extent of projected eventual future biome change in areas of past constant biome. Results Approximately 11% of global ice-free land had a constant biome since 140 ka. Apart from areas of constant Desert, many areas with constant biome support high species diversity. All terrestrial vertebrate groups show a strong positive relationship between biome constancy and vertebrate diversity in areas of greater diversity, but no relationship in less diverse areas. Climatic change projected by 2100 commits 46%-66% of global ice-free land, and 34%-52% of areas of past constant biome (excluding areas of constant Desert) to eventual biome change. Main conclusions Past biome stability strongly predicts vertebrate diversity in areas of higher diversity. Future climatic changes will lead to biome changes in many areas of past constant biome, with profound implications for biodiversity conservation. Some projected biome changes will result in substantial reductions in biospheric carbon sequestration and other ecosystem services.

Despite growing interest in using lightweight unmanned aerial systems (UASs) for ecological research and conservation, review of the operational aspects of these evolving technologies is limited in the scientific literature. To derive an objective framework for choosing among technologies we calculated efficiency measures and conducted a data envelopment productivity frontier analysis (DEA) to compare the efficacy of using manned aircraft (Cessna with Aviatrix triggered image capture using a 50 mm lens) and UAS (Mavic Pro 2) for photogrammetric monitoring of restoration efforts in dynamic braided rivers in Southern New Zealand. Efficacy assessment was based on the technological, logistical, administrative, and economic requirements of pre (planning), peri (image acquiring) and post (image processing) phases. The results reveal that the technological and logistic aspects of UASs were more efficient than manned aircraft flights. Administratively, the first deployment of UASs is less efficient but was very flexible for subsequent deployment. Manned aircraft flights were more productive in terms of the number of acquired images, but the ground resolution of those images was lower compared with those from UASs. Frontier analysis confirmed that UASs would be economical for regular monitoring of habitats—and even more so if research personnel are trained to fly the UASs.

In response to anthropogenic threats, conservation translocations are increasingly used to combat species' population and range declines. However, moving animals outside of their current distribution can mean introducing them to novel conditions, even in the case of reintroductions to formerly inhabited areas due to ecosystem changes following extirpation. This exposure to novel conditions introduces uncertainty that can undermine decision making for species conservation. Here we propose two strategies, which we define as conservative and extrapolative, for approaching and managing novelty and the resulting uncertainty in conservation translocations. Conservative strategies are characterised by the avoidance and removal of novel conditions as much as possible, whereas extrapolative strategies are more experimental, allowing exposure to novel conditions and monitoring outcomes to increase understanding of a species' ecology. As each strategy carries specific risks and opportunities, they will be applicable in different scenarios. Extrapolative strategies suit species in recovery which can afford some experimental management, or species facing novel and emerging threats which require less traditional translocations, such as assisted colonisations. We provide examples, applying our framework to two endemic New Zealand species with long histories of translocation management: tuatara (Sphenodon punctatus), a reptile and takahē (Porphyrio hochstetteri), a flightless bird.

Species reintroductions are high-investment ecological interventions that require careful planning. Predictive models are useful tools for managing reintroductions. We provide an overview of habitat suitability, dispersal, population dynamics and interspecies models, considering potential uses and limitations of established methods for reintroductions. Furthermore, we include a guide for integrating one or more model types to predict reintroduction outcomes and answer specific management questions. Model utility will be maximized by considering the goals of the reintroduction, attributes of the reintroduced species, threats to persistence and the quality of available data. Synthesis and applications. Our synthesis of state-of-the-art ecological models outlines how key ecological models can be applied to reintroductions. Our review can aid practitioners undertaking reintroductions to assess and quantify their data and modelling needs in line with their management goals.

Land cover change is a key component of anthropogenic global environmental change, contributing to changes in environmental conditions of habitats. Deforestation is globally the most widespread and anthropogenically driven land cover change leading to conversion from closed forest to open non-forest habitat. This study investigates the relative roles of geographic features, characteristics of species climatic niche and species traits in determining the ability of open-habitat plant species to take advantage of recently opened habitats. We use current occurrence records of 18 herbaceous, predominantly open-habitat species of the genus Acaena (Rosaceae) to determine their prevalence in recently opened habitat. We tested correlation of species prevalence in anthropogenically opened habitat with (i) geographic features of the spatial distribution of open habitat, (ii) characteristics of species climatic niche, and (iii) species traits related to dispersal. While primary open habitat (naturally open) was characterised by cold climates, secondary open habitat (naturally closed but anthropogenically opened) is characterised by warmer and wetter conditions. We found high levels of variation in the species prevalence in secondary open habitat indicating species differences in their ability to colonise newly opened habitat. For the species investigated, geographical features of habitat and climatic niche factors showed generally stronger relationships with species prevalence in secondary open habitat than functional traits. Therefore, for small herbaceous species, geographical features of habitat and environmental factors appear to be more important than species functional traits for facilitating expansion into secondary open habitats. Our results suggested that the land cover change might have triggered the shifts of factors controlling open-habitat plant distributions from the competition with forest trees to current environmental constraints.

The Otago Museum houses one of New Zealand’s largest Lepidoptera collections that consists of more than 31,000 macro moth specimens collected across New Zealand over the last 30 years. Alongside this collection, supplementary information is found in detailed field notebooks that cover, for most sites, the total abundance of the different species present in these samples. We have been able to use the notebooks to work out the sampling intensity and sites to map both the collections and the abundances to some degree. It is impractical to collect everything. As a result, the common species are left out of collections and the rare and unusual sightings fill the collections. When planning to resample collecting sites to investigate changes in ecosystems, just relying on collections for species presence and absence would skew the results. It should also be noted that field notebooks are not a panacea for biological information as the information in them ages, so too can the reliability and accuracy of the notes within. Here we discuss how the field notebook data compares with the information accompanying the specimens housed within the museum collection. This is a recently digitised collection and allows an insight into the collectors sampling, vouchering and data practices and how these can affect modern interpretation and variation in repeat sampling.

Aim: More than 90% of plant species found in New Zealand's alpine environment are endemic to New Zealand. Two particularly species-rich regions of high endemism are located at the northern and southern ends of the South Island and several vascular alpine plant species show clear disjunct distributions between these two regions. The aim of this study was to test the ability of a climatic hypothesis to explain these disjunct distributions and to identify if the central South Island acts as a climatic barrier. Location: Alpine South Island, New Zealand. Methods: The South Island was divided into three regions (northern, central, southern) following an established biogeographical delineation of centres of endemism. Published data were used to quantify current climatic conditions and to obtain occurrence records of all plant species occurring in the alpine areas. We first calculated overall similarity in climate and in vegetation composition above and below the tree line between the three regions. We then assessed climate niche overlap between regions for five congeneric pairs of disjunct and continuous plant species found both above and below the tree line. Results: While there were broad scale similarities in climate between northern and southern centres of endemism, particular above the tree line, the central region does not appear sufficiently dissimilar to the climate of the endemism centres to conclude that it might act as a barrier between populations of the disjunct species investigated here. Instead, we showed that in geographically separated areas, disjunct species occupy less similar climates than species with a continuous range, possibly indicating a niche shift of the disjunct populations in the separated areas. Main conclusions: Our study found no support for current climate constraining the distribution of disjunct species. For all species examined, overlap existed between the climate niche of at least one disjunct northern or southern population and the climatic conditions of the central region. This overlap in climate space suggests that other abiotic and/or biotic factors are preventing the spread of disjunct species into the central South Island endemism gap.

Previous phenological image analysis works use mostly close-up images or satellite remote sensing images. In this paper we employ ground-based tree images to investigate two related research tasks: colouring trends analysis and tree categorization. In the first task, we extracted a few colour features of image regions of three tree types: exotic deciduous, native non-deciduous, and native deciduous, from photographs taken in a period from spring to summer, to find out whether there are distinguishable colouring trends in different seasons and in different tree types. Statistical tests are carried out to verify the significance of our findings. In the tree categorization work, we examine possible image features that can be utilised for classifying trees into three types. Various classification schemes are explored, including using individual classifiers as well as classifier ensembles such as random forests. The colour trend analysis shows that the two native species have increasingly similar greening and hue from spring to summer, while the two deciduous types have similar change patterns matching their leaf growth trends. The tree categorization result shows that the highest F1 score is over 71% achieved by SVM and Random Forests classifiers. The HSV features are the most effective features for classification.

Indigenous grassland ecosystems worldwide are increasingly subject to shrub encroachment. A key factor determining encroachment patterns is the availability of shrub propagules in the areas surrounding the grasslands. We here provide a multi‐scale spatial analysis of the geographic distribution (geographic space) and the climatic conditions (environmental space) of potential native and exotic shrub propagule pressure for New Zealand's main grassland types. We show that alpine grasslands are most at risk from native, and low‐producing grasslands are most at risk from exotic shrub propagule pressure. Inferred spatial patterns of potential propagule pressure differ between the local, landscape and regional scale.

Most ecological studies of the effects of climate on species are based on average conditions above ground level (measured by meteorological stations) averaged across 100 km2 or larger areas. However, most terrestrial organisms experience conditions in a much smaller area at the ground surface or within vegetation canopies, the climate of which can be very different to large-scale averages. Therefore, to accurately characterise the climatic conditions suitable for species, it is essential to include microclimate information. Microclimates are affected by the shape of the landscape, including the steepness and aspect of slopes, height above sea level, proximity to the sea or inland water, and whether a site is in a valley or at the top of a hill. Plants also modify the conditions found within or below their canopies, with the structure of vegetation playing an important role. The recent increase in the availability of microsensors and remotely sensed data at appropriate resolutions has led some ecologists to begin to include microclimate information within a variety of contexts; however the field can be confusing and intimidating and mistakes are often made along the way. In this chapter, we provide an overview of microclimatic processes and summarise the available methods of measuring and modelling microclimate data for incorporation in ecological research. We highlight pitfalls to avoid emerging novel methods and the limitations of some techniques. We also consider future research directions and opportunities within this emerging field.

Structural equation model diagram for species richness of habitat specialist butterflies when using only the main host plants of habitat specialists.

Summary Ecologists often wish to describe mathematical relationships between response variables and climate covariates in spatial models of species distribution; these relationships are commonly termed climate envelopes. There are many situations when the functional form of the envelopes should be either unimodal or monotonic, but current practice tends towards the use of either low‐degree single‐variable spline curves fitted as part of a Generalised Additive Model (GAM) or piecewise linear forms in software such as maxent. We argue that such curves are often inappropriate, as they: (i) can easily produce relationships which are ecologically implausible and (ii) frequently ignore interactions between multiple climate variables in a general regression context. We propose an novel alternative parametric form for climate envelopes that appeals to ecological plausibility and can encompass realistic features of species' presence/climate relationships on several variables simultaneously. The proposed plateau climate envelope function is applied via a spatial Bayesian species distribution model to data on two European tree species to demonstrate the approach. For Fagus sylvatica, a complete climate envelope is estimable, but for Quercus coccifera, only a partial climate envelope can be estimated as the geographical extent of the data set does not cover the full environmental niche for the species. We show that such an approach is practical, produces climate envelopes with an ecologically meaningful form and furthermore allows the inclusion of information external to the data set being analysed. We discuss the use of this new plateau climate envelope function in the context of ecological niche modelling and argue that in some instances ecological realism should be regarded as more important than the use of formal model comparison statistics.

Aim Test hypotheses that present biodiversity and endemic species richness are related to climatic stability and/or biome persistence.Location Africa south of 15 degrees S.Methods Seventy eight HadCM3 general circulation model palaeoclimate experiments spanning the last 140,000 years, plus a pre-industrial experiment, were used to calculate measures of climatic variability for 0.5 degrees grid cells. Models were fitted relating distributions of the nine biomes of South Africa, Lesotho and Swaziland to present climate. These models were used to simulate potential past biome distribution and extent for the 78 palaeoclimate experiments, and three measures of biome persistence. Climatic response surfaces were fitted for 690 bird species regularly breeding in the region and used to simulate present species richness for cells of the 0.5 degrees grid. Species richness was evaluated for residents, mobile species (nomadic or partially/altitudinally migrant within the region), and intra-African migrants, and also separately for endemic/near-endemic (hereafter 'endemic') species as a whole and those associated with each biome. Our hypotheses were tested by analysing correlations between species richness and climatic variability or biome persistence.Results The magnitude of climatic variability showed clear spatial patterns. Marked changes in biome distributions and extents were projected, although limited areas of persistence were projected for some biomes. Overall species richness was not correlated with climatic variability, although richness of mobile species showed a weak negative correlation. Endemic species richness was significantly negatively correlated with climatic variability. Strongest correlations, however, were positive correlations between biome persistence and richness of endemics associated with individual biomes.Main conclusions Low climatic variability, and especially a degree of stability enabling biome persistence, is strongly correlated with species richness of birds endemic to southern Africa. This probably principally reflects reduced extinction risk for these species where the biome to which they are adapted persisted.

Our aim was to seek explanations for the differences in the diversity among the austral continents by comparing the diversification rates and patterns in the grass subfamily Danthonioideae. We asked specifically whether diversification is density dependent, whether it is different for each continent, and whether immigration rates impact on diversification rates. We attempted to account for intercontinental differences by comparing the Pleistocene climatic and Neogene geomorphological histories with the inferred diversification rates.