Margaret E Andrew

Context
Parasitic plants are widespread throughout the global flora and have diverse lifestyle strategies. In most cases these plants are detrimental to the host but may have some beneficial effects on the co-occurring plants in the sourrounding communities. Some have large macroscopic plant bodies and can photosynthesise, and are therefore able to produce some fixed carbon but do take water and nutrients from the host, especially if aerially attached. Very few species have vegetative parts completely enclosed in the host, having only reproductive structures externally displayed. Whether such internal parasites have as severe effects on the host as parasites with macroscopic plant bodies is unclear.

Aims
The endoparasite Pilostyles hamiltoniorum infests pea species (predominantly Daviesia species) in the south-west of Western Australia. We investigated the effect of this parasite on the vegetative growth and reproduction of Daviesia angulata in heathland vegetation.

Methods
Size, flowering and fruiting of parasitised and unparasitised host plants were recorded in three 6 × 30 m plots in a revegetated gravel pit in the Jurien Bay area of Western Australia.

Key results
A proportion of 21% of host plants was parasitised and these were significantly taller than unparasitised plants. These plants had 52% fewer flowers on average than unparasitised plants and subsequently far fewer fruits.

Conclusions
The reduction in reproductive output by this internal parasite was at least equal to or more severe than occurs in published examples of decreased productivity of other species parasitised by species with macroscopic plant morphology.

Implications
The reduced reproductive output of the host plants would be inimical to seed stores in the soil that this species relies on for regeneration after fires that commonly affect the vegetation in this region.

Since 2004, airborne hyperspectral imagery has been acquired over the Sacramento - San Joaquin Delta in northern California to map submerged and floating invasive species and study how they affect the Delta ecosystem. Acquiring imagery over 2220 square kilometers of the Delta typically required 60-70 flightlines each year, which were then further processed to surface reflectance, georegistered, and prepared for analysis. Further, each flightline was processed using multiple spectral mapping methods such as spectral angle mapper, spectral mixture analysis, spectral indexes, and continuum removal over water and cellulose absorption bands. The outputs of these transformations were used as inputs to a Random Forests classifier. Concurrent with image acquisition, field data (800-2000 points) were collected across the Delta for training and validation of the classification products. The field data were divided into test and training polygons. These polygons were overlaid on the transformed files and pixel data were extracted corresponding to the polygons. The training data were used to train the Random Forests classifier to identify 10 classes (water, submerged aquatic vegetation, emergent marsh, soil, non-photosynthetic vegetation, water hyacinth, water primrose, pennywort, shadow, riparian vegetation). The classifier was validated quantitatively using the test data at both pixel and polygon level using overall accuracy and kappa metrics. The classifier was then applied to all flightlines and class maps were produced. Mosaics of these class maps are published in this dataset.

A number of native species, including species of conservation concern, are found in cities worldwide. However, the persistence of these populations is uncertain given the extinction debt fragmented urban ecosystems are likely to face. We used species distribution modelling and graph theory to evaluate the ability of connected habitat networks to sustain viable populations of quenda (Isoodon fusciventer), a priority near-threatened mammal species, in the urban and peri-urban landscapes of Perth, Western Australia. Quenda habitat was associated with native remnants and adjacent perennial vegetation in the urban matrix, and occurred most prominently on commercial, education, and industrial land uses. We evaluated connectivity models corresponding to two movement behaviours: routine daily movements within the home range and annual home range shifts, finding that annual scale movements are most important for connectivity. At this scale, quenda habitat was relatively well connected. Most (68–80 %) of the suitable habitat (9–10 % of the study area) met minimum viable area (MVA) requirements when assessed as part of a connected habitat network. However, this is divided into 10–30 disconnected populations and quenda are unlikely to persist in the most densely developed areas. Our results can be used to guide planning so that viable populations are not lost or subdivided by ongoing urban development. They also highlight where urban greening might restore connectivity to ‘rescue’ declining populations that do not currently have access to an MVA. Quenda are beloved by urban residents; their sustained presence throughout Perth enhances people's connection to nature and may strengthen support for conservation.
•Threatened species may persist in urban areas if sufficient habitat is accessible•Accessible habitat area depends on species niche, movement ability, and connectivity•Species distribution model and graph theory used to assess urban quenda habitat•Quenda perceive habitat as fairly connected, likely to persist in Perth, Australia•More data needed on home range shifts and wildlife movements in urban environments

Since 2004, airborne hyperspectral imagery has been acquired over the Sacramento - San Joaquin Delta in northern California to map submerged and floating invasive species and study how they affect the Delta ecosystem. Acquiring imagery over 2220 square kilometers of the Delta typically required 60-70 flightlines each year, which were then further processed to surface reflectance, georegistered, and prepared for analysis. Further, each flightline was processed using multiple spectral mapping methods such as spectral angle mapper, spectral mixture analysis, spectral indexes, and continuum removal over water and cellulose absorption bands. The outputs of these transformations were used as inputs to a Random Forests classifier. Concurrent with image acquisition, field data (800-2000 points) were collected across the Delta for training and validation of the classification products. The field data were divided into test and training polygons. These polygons were overlaid on the transformed files and pixel data were extracted corresponding to the polygons. The training data were used to train the Random Forests classifier to identify 10 classes (water, submerged aquatic vegetation, emergent marsh, soil, non-photosynthetic vegetation, water hyacinth, water primrose, pennywort, shadow, riparian vegetation). The classifier was validated quantitatively using the test data at both pixel and polygon level using overall accuracy and kappa metrics. The classifier was then applied to all flightlines and class maps were produced. Mosaics of these class maps are published in this dataset.

The essential biodiversity variables (EBV) framework has been proposed as a monitoring system of standardized, comparable variables that represents a minimum set of biological information to monitor biodiversity change at large spatial extents. Six classes of EBVs (genetic composition, species populations, species traits, community composition, ecosystem structure and ecosystem function) are defined, a number of which are ideally suited to observation and monitoring by remote sensing systems. We used moderate-resolution remotely sensed indicators representing two ecosystem-level EBV classes (ecosystem structure and function) to assess their complementarity and redundancy across a range of ecosystems encompassing significant environmental gradients. Redundancy analyses found that remote sensing indicators of forest structure were not strongly related to indicators of ecosystem productivity (represented by the Dynamic Habitat Indices; DHIs), with the structural information only explaining 15.7% of the variation in the DHIs. Complex metrics of forest structure, such as aboveground biomass, did not contribute additional information over simpler height-based attributes that can be directly estimated with light detection and ranging (LIDAR) observations. With respect to ecosystem conditions, we found that forest types and ecosystems dominated by coniferous trees had less redundancy between the remote sensing indicators when compared to broadleaf or mixed forest types. Likewise, higher productivity environments exhibited the least redundancy between indicators, in contrast to more environmentally stressed regions. We suggest that biodiversity researchers continue to exploit multiple dimensions of remote sensing data given the complementary information they provide on structure and function focused EBVs, which makes them jointly suitable for monitoring forest ecosystems.

Aim
There is widespread support that species richness increases with the available energy of an ecosystem, but the mechanisms underlying this driver of biodiversity patterns remain elusive. We evaluated gradients of functional diversity to test whether the higher species richness of productive, structurally diverse environments is due to a greater range of niches being supported by the abiotic conditions present (environmental filtering), greater availability of biotic resource and habitat niches (more niches) or increasing functional similarity of species (niche packing).

Location
Australia.

Taxon
Birds and mammals.

Methods
We used structural equation modelling to evaluate the relative contributions of climatic harshness (actual evapotranspiration, AET) and the availability of resource (gross primary productivity, GPP) and habitat (tree height) niches on taxonomic richness and functional richness, dispersion and evenness. We performed parallel analyses within 15 bioclimatic zones and continentally to evaluate the scaling of biodiversity gradients and the shifting balance between niche-based mechanisms along environmental gradients.

Results
All continental diversity gradients were primarily associated with energy variables, but while species richness of both taxa and all functional diversity measures of bird assemblages increased with AET, mammal functional diversity was more strongly associated with GPP gradients. Results were more variable at the regional scale, but species richness gradients along tree height (birds and mammals) and GPP (mammals) within bioclimatic zones tended not to be paralleled by increases in functional richness or dispersion.

Main Conclusions
The niche-based explanations of biodiversity gradients varied in importance with scale, position on environmental gradients and taxonomic group. At the continental extent, bird biodiversity gradients were structured by environmental filtering by climatic harshness, while mammal biodiversity was related to the increasing availability of resource niches with increasing productivity. Niche packing was more prominent at the regional scale, especially in bioclimatic zones where productivity and vegetation height were less limiting, and in mammal assemblages, suggesting that biodiversity patterns scale differently for birds and mammals.

Spatial planning and environmental management are expected to adopt participatory processes. However, the needed spatial data on social values of ecosystem services are limited, especially for marine spatial planning for large, remote coastal areas, and the collection of such information can be time and resource intensive. Crowdsourcing techniques are cost efficient sources of social values data, but must meet the information needs of planners and managers with sufficient confidence. We evaluated the reliability of crowdsourced social values data by assessing the agreement between geotagged photos posted to the social media platform Flickr and data from an online public participation GIS (PPGIS) survey conducted to support marine spatial planning in the Kimberley region of Western Australia.

Flickr could not represent all of the social values mapped in the PPGIS dataset, was notably dominated by scenic values, and under-represented the importance of recreational fishing and Aboriginal cultural values. The Flickr dataset was more affected by accessibility from settlements and transportation infrastructure (roads, boat ramps) and more restricted spatially. Maximum entropy (maxent) distribution models developed to explore the socioecological drivers determining where social values occur also highlighted that Flickr and PPGIS samples provide different perspectives on social values, even after accounting for differences in sampling intensity. The Flickr dataset suggested that the social values occurred under narrower ranges of socioecological conditions, and the PPGIS dataset was more likely to find protected areas to be valued, likely because participants believe protected areas to support those social values, but may not themselves pursue them there.

Flickr and PPGIS crowdsourced datasets provide different perspectives on the spatial distribution of social values for several reasons: They differ in their spatial and demographic biases, as well as their measurement of revealed vs. stated preferences. Flickr is most effective at representing social values that are easily photographed and interpretable in photos, and may not capture some information needs of managers. PPGIS is under greater investigator control but, because stated preferences can be disconnected from actual use of the sites mapped, may be best suited for assessing management preferences and social acceptability. With understanding of the nuances of these datasets, crowdsourced social values data can be applied most appropriately to support successful planning outcomes.

Background
In recent decades, fire has increasingly occurred in the tropical montane rainforests of northern Vietnam. However, there are few studies of the effects of fire on forest composition and recovery in this region, and understanding these effects is critical for effective forest fire management and conservation. Forest plant species richness, structure (density, basal area), and composition were quantified for 133 forest plots randomly located in unburned (> 20 years since last fire) and recently burned (3–9 years since fire) vegetation associated with ten selected wildfires in three provinces of northern Vietnam where fires since 2000 were most frequent. Linear mixed effect models and nonmetric multidimensional scaling (NMDS) ordination were used to explore the structure, richness, and composition of burned and unburned forests and their environmental drivers, and to explore the key drivers of regeneration patterns in burned forest, including time since fire occurrence, fire severity, and distance to unburned forest edge.

Results
Total species richness and diversity, tree species richness, tree density, and basal area were higher in unburned (vs. burned) forest plots, low (vs. high) severity burn areas, near (vs. far) from the closest unburned forest edge, and longer (vs. shorter) time since last fire. Results suggest that while burned forests were recovering on a trajectory back towards unburned forest composition, recovery was likely to be markedly slowed where fires were large (distance from edge effects) and/or of high severity, and forests may shift towards a different state (i.e., composition and structure) where more than one fire affects the same area over short time intervals.

Conclusions
This study provides insights into the effects of fire and other environmental factors on forest composition and recovery in the tropical montane forests of northern Vietnam, crucial for informing policymakers involved in forest conservation and management.

Background

Fire impacts and drivers of wildfire burn severity remain poorly understood for tropical forests.

Aims

To assess variation and environmental drivers of burn severity for nine forest fires in northern Vietnam.

Methods

Burn severity was estimated from satellite image analyses, and associations with a remotely sensed index of annual fuel production, topographic factors (elevation, slope, aspect) and weather variables (temperature, rainfall, relative humidity, wind speed) were evaluated.

Key results

High severity burn areas were found to be fairly uncommon and were associated with steeper, south-west facing slopes, higher elevations and lower fuel abundance. There was a weak tendency for higher burn severity on days with lower relative humidity.

Conclusions

Conditions that increase fire intensity and the dryness and flammability of fuels are important contributors to high severity fires in wet tropical systems. However, the pattern of higher burn severity at high elevation, where forests tend to be denser and more humid, is counter to this interpretation and may be due to species compositional changes and greater vulnerability of high-elevation forests to fire impacts.

Implications

Better understanding of fire risk and where in the montane forests of northern Vietnam fires are most likely to burn at high severity will assist forest fire management and recovery strategies.

Invasive plant species (IPS) management in national parks is a complex problem often characterised by the involvement of various organisations with different responsibilities, legal mandates, and jurisdictions. These institutional arrangements shape the structure, function, and decision-making behaviours of organisations and influence management effectiveness. Drawing on institutional theory, this study analysed institutional arrangements and how these influenced IPS management in national parks of Vietnam. Data were collected between May and July 2017 using in-depth interviews with 39 key informants with responsibilities for IPS management at different institutional levels (national, provincial, local national parks). Results demonstrated that IPS management in Vietnam’s national parks was characterised by centralised management with overlaps and gaps in vertical institutional relationships that limited the effectiveness of horizontal relationships. These characteristics resulted in a lack of clear guiding regulations and limited resources that restricted decision making and hindered implementation at the local national park level. The study highlights the need for a common set of principles across agencies, governed by an overarching body to promote constructive relationships across the vertical and horizontal institutional dimensions of IPS management.