KEVIN J GASTON

Gonzalez, L.F., Montes, G.A., Puig, E., Johnson, S., Mengersen, K. & Gaston, K.J. (2016) Unmanned Aerial Vehicles (UAVs) and Artificial Intelligence revolutionizing wildlife monitoring and conservation. Sensors 16(1), 97. (Image from Shutterstock)

Surveying threatened and invasive species to obtain accurate population estimates is an important but challenging task that requires a considerable investment in time and resources. Estimates using existing ground-based monitoring techniques, such as camera traps and surveys performed on foot, are known to be resource intensive, potentially inaccurate and imprecise, and difficult to validate. Recent developments in unmanned aerial vehicles (UAV), artificial intelligence and miniaturized thermal imaging systems represent a new opportunity for wildlife experts to inexpensively survey relatively large areas. The system presented in this paper includes thermal image acquisition as well as a video processing pipeline to perform object detection, classification and tracking of wildlife in forest or open areas. The system is tested on thermal video data from ground based and test flight footage, and is found to be able to detect all the target wildlife located in the surveyed area. The system is flexible in that the user can readily define the types of objects to classify and the object characteristics that should be considered during classification.

Yvon-Durocher, G., Allen, A. P., Cellamare, M., Dossena, M., Gaston, K. J., Leitao, M., Montoya, J. M., Reuman, D. C., Woodward, G. & Trimmer, M. (2015) Five Years of Experimental Warming Increases the Biodiversity and Productivity of Phytoplankton. PLoS Biology 13(12): e1002324. (Image from Shutterstock)

Phytoplankton are key components of aquatic ecosystems, fixing CO2 from the atmosphere through photosynthesis and supporting secondary production, yet relatively little is known about how future global warming might alter their biodiversity and associated ecosystem functioning. Here, we explore how the structure, function, and biodiversity of a planktonic metacommunity was altered after five years of experimental warming. Our outdoor mesocosm experiment was open to natural dispersal from the regional species pool, allowing us to explore the effects of experimental warming in the context of metacommunity dynamics. Warming of 4°C led to a 67% increase in the species richness of the phytoplankton, more evenly-distributed abundance, and higher rates of gross primary productivity. Warming elevated productivity indirectly, by increasing the biodiversity and biomass of the local phytoplankton communities. Warming also systematically shifted the taxonomic and functional trait composition of the phytoplankton, favoring large, colonial, inedible phytoplankton taxa, suggesting stronger top-down control, mediated by zooplankton grazing played an important role. Overall, our findings suggest that temperature can modulate species coexistence, and through such mechanisms, global warming could, in some cases, increase the species richness and productivity of phytoplankton communities.

Durán, A. P., Inger, R., Cantú‐Salazar, L. & Gaston, K. J. (2015) Species richness representation within protected areas is associated with multiple interacting spatial features. Diversity and Distributions, in press. DOI: 10.1111/ddi.12404. (Image from Shutterstock)

We assessed the relative effects of the spatial features of protected areas (PAs), and their interactions, on species richness representation. We used a novel dataset comprising species richness estimates for amphibians, birds and mammals for more than 400 PAs in the Western Hemisphere. Using spatial tools and remote sensing imagery, we calculated four spatial features for each PA: size, shape index, fragmentation level and proximity to the closest PA. The relative effect size of both PA spatial features and environmental covariates on levels of species richness, and how they interact, were assessed using generalized mixed effect models. Spatial features and environmental covariates explained about 61% of the variation in species richness within PAs, with the magnitude of the effect remaining similar among spatial features and taxonomic groups. While area had a positive effect on species richness, shape index and fragmentation had negative effects. Proximity had a significant positive effect only for mammals and a negative effect for all the taxa combined. PA spatial features showed significant interactions between them and with environmental covariates. We provide the first empirical evidence for the combined and interactive effects of terrestrial PA spatial features on predicting species richness. Our results suggest that the spatial features of PAs have an important effect on species richness and while the magnitude of this effect varies across taxonomic groups, its direction is consistent. Additionally, we show that the effect of one spatial design feature can be amplified or attenuated by that of another. These findings contribute towards a better understanding of the effect of spatial features on the performance of PAs and therefore how best to enhance the spatial configuration of existing and future PAs.

Stanley, M.C., Beggs, J.R., Bassett, I.E., Burns, B.R., Dirks, K.N., Jones, D.N., Linklater, W.L., Macinnis-Ng, C., Simcock, R., Souter-Brown, G., Trowsdale, S.A. & Gaston, K.J. (2015) Emerging threats in urban ecosystems: a horizon scanning exercise. Frontiers in Ecology and the Environment 13(10): 553–560. (Image from Shutterstock)

As urbanization intensifies, urban ecosystems are increasingly under pressure from a range of threats. Horizon scanning has the potential to act as an early warning system, thereby initiating prompt discussion and decision making about threat mitigation. We undertook a systematic horizon scanning exercise, using a modified Delphi technique and experts from wide-ranging disciplines, to identify emerging threats in urban ecosystems. The 10 identified threats were generally associated with rapid advances in technology (eg solar panels, light-emitting diode lights, self-healing concrete) or with societal demands on urban nature (eg green prescriptions). Although many of the issues identified are also technological opportunities with recognized environmental benefits, we have highlighted emerging risks so that research and mitigation strategies can be initiated promptly. Given the accelerated rate of technological advancement and the increasing demands of urbanized populations, horizon scanning should be conducted routinely for urban ecosystems.

Cox, D.T.C. & Gaston, K.J. (2015) Likeability of garden birds: importance of species knowledge & richness in connecting people to nature. PLoS ONE 10(11), e0141505. (Image from Shutterstock)

Interacting with nature is widely recognised as providing many health and well-being benefits. As people live increasingly urbanised lifestyles, the provision of food for garden birds may create a vital link for connecting people to nature and enabling them to access these benefits. However, it is not clear which factors determine the pleasure that people receive from watching birds at their feeders. These may be dependent on the species that are present, the abundance of individuals and the species richness of birds around the feeders. We quantitatively surveyed urban households from towns in southern England to determine the factors that influence the likeability of 14 common garden bird species, and to assess whether people prefer to see a greater abundance of individuals or increased species richness at their feeders. There was substantial variation in likeability across species, with songbirds being preferred over non-songbirds. Species likeability increased for people who fed birds regularly and who could name the species. We found a strong correlation between the number of species that a person could correctly identify and how connected to nature they felt when they watched garden birds. Species richness was preferred over a greater number of individuals of the same species. Although we do not show causation this study suggests that it is possible to increase the well-being benefits that people gain from watching birds at their feeders. This could be done first through a human to bird approach by encouraging regular interactions between people and their garden birds, such as through learning the species names and providing food. Second, it could be achieved through a bird to human approach by increasing garden songbird diversity because the pleasure that a person receives from watching an individual bird at a feeder is dependent not only on its species but also on the diversity of birds at the feeder.

Anderson, K., Hancock, S., Disney, M. & Gaston, K.J. (2015) Is waveform worth it? A comparison of LiDAR approaches for vegetation and landscape characterization. Remote Sensing in Ecology and Conservation, in press. (Image from Shutterstock)

Light Detection and Ranging (LiDAR) systems are frequently used in ecological studies to measure vegetation canopy structure. Waveform LiDAR systems offer new capabilities for vegetation modelling by measuring the time-varying signal of the laser pulse as it illuminates different elements of the canopy, providing an opportunity to describe the 3D structure of vegetation canopies more fully. This article provides a comparison between waveform airborne laser scanning (ALS) data and discrete return ALS data, using terrestrial laser scanning (TLS) data as an independent validation. With reference to two urban landscape typologies, we demonstrate that discrete return ALS data provided more biased and less consistent measurements of woodland canopy height (in a 100% tree covered plot, height underestimation bias = 0.82 m;SD = 1.78 m) than waveform ALS data (height overestimation bias = −0.65 m; SD = 1.45 m). The same biases were found in suburban data (in a plot consisting of 100% hard targets e.g. roads and pavements), but discrete return ALS were more consistent here than waveform data (SD = 0.57 m compared to waveform SD = 0.76 m). Discrete return ALS data performed poorly in describing the canopy understorey, compared to waveform data. Our results also highlighted errors in discrete return ALS intensity, which were not present with waveform data. Waveform ALS data therefore offer an improved method for measuring the three-dimensional structure of vegetation systems, but carry a higher data processing cost. New toolkits for analysing waveform data will expedite future analysis and allow ecologists to exploit the information content of waveform LiDAR.

Goettsch, B., Hilton-Taylor, C., Cruz-Piñón, G., Duffy, J.P., Frances, A., et al. (2015) High proportion of cactus species threatened with extinction. Nature Plants 1, 15142. (Image from Shutterstock)

A high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groups.

Soga, M., Yamaura, Y., Aikoh, T., Shoji, Y., Kubo, T. & Gaston, K.J. (2015) Reducing the extinction of experience: Association between urban form and recreational use of public greenspace. Landscape and Urban Planning 143, 69-75.
(Image from Shutterstock)

Halting the ‘extinction of experience’, the progressive disengagement of people with the natural world, is vital to human health and wellbeing and to public support for global biological conservation. Home to the majority of humanity, urban areas are the key for engaging people with nature, raising the crucial question of how cities should best be designed to facilitate these experiences. For the purposes of maintaining local biodiversity, intensive development within a small area (land sparing) has been shown to be better than extensive development over a large area (land sharing). Here, we investigated for the first time how different city forms affect people’s experience of nature, measured in terms of their use of greenspaces. We selected five pairs of land-sharing and land-sparing study regions with different coverage by greenspaces within the city of Tokyo, central Japan and used a questionnaire survey to determine the use residents made of these spaces. We found the frequency of people’s recreational use of urban greenspaces was higher in urban land-sharing than land-sparing regions. Moreover, satisfaction with local green environments was also higher in land-sharing regions. This suggests a potential conflict in the design of cities between the urban form that is most desirable for the direct protection of regional biodiversity, and that which best promotes people’s nature experiences and the support for its wider protection. A strong emphasis on the advantages of land sparing may increase the separation of humans from nature, and further reduce public interest in, and awareness of, biodiversity and its benefits.