Shared posts

28 Jun 16:06

Evolutionary responses to global change: lessons from invasive species

by Emily V. Moran, Jake M. Alexander


Biologists have recently devoted increasing attention to the role of rapid evolution in species' responses to environmental change. However, it is still unclear what evolutionary responses should be expected, at what rates, and whether evolution will save populations at risk of extinction. The potential of biological invasions to provide useful insights has barely been realised, despite the close analogies to species responding to global change, particularly climate change; in both cases, populations encounter novel climatic and biotic selection pressures, with expected evolutionary responses occurring over similar timescales. However, the analogy is not perfect, and invasive species are perhaps best used as an upper bound on expected change. In this article, we review what invasive species can and cannot teach us about likely evolutionary responses to global change and the constraints on those responses. We also discuss the limitations of invasive species as a model and outline directions for future research.

10 May 20:59

Aquatic primary production in a high-CO2 world

Etienne Low-Décarie, Gregor F. Fussmann, Graham Bell.
• Elevated CO2 is likely to alter aquatic primary production.
• Changes in CO2 cause predictable shifts in phytoplankton community composition.
15 Apr 20:54

Modelling surface fine fuel dynamics across climate gradients in eucalypt forests of south-eastern Australia

by P. B. Thomas, P. J. Watson, R. A. Bradstock, T. D. Penman, O. F. Price

An understanding of the effects of climate on fuel is required to predict future changes to fire. We explored the climatic determinants of variations in surface fine fuel parameters across forests (dry and wet sclerophyll plus rainforest) and grassy woodlands of south-eastern Australia. Influences of vegetation type and climate on fuel were examined through statistical modelling for estimates of litterfall, decomposition and steady state fine litter fuel load obtained from published studies. Strong relationships were found between climate, vegetation type and all three litter parameters. Litterfall was positively related to mean annual rainfall and mean annual temperature across all vegetation types. Decomposition was both negatively and positively related to mean annual temperature at low and high levels of warm-season rainfall respectively. Steady state surface fine fuel load was generally, negatively related to mean annual temperature but mean annual rainfall had divergent effects dependent on vegetation type: i.e. positive effect in low productivity dry sclerophyll forests and grassy woodlands versus negative effect in high productivity wet sclerophyll forests and rainforests. The species composition of the vegetation types may have influenced decomposition and steady state fuel load responses in interaction with climate: e.g. lower decomposition rates in the low productivity vegetation types that occupied drier environments may be partially due to the predominance of species with sclerophyllous leaves. The results indicate that uncertain and highly variable future trends in precipitation may have a crucial role in determining the magnitude and direction of change in surface fine fuel load across south-eastern Australia.

15 Apr 20:54

Metapopulation dynamics of a beetle species confined to burned forest sites in a managed forest region

by Thomas Ranius, Petter Bohman, Olof Hedgren, Lars-Ove Wikars, Alexandro Caruso

Despite increasing awareness of the theoretical importance of habitat dynamics on metapopulations, only a few empirical studies have been conducted. We aimed to increase our understanding of how patch size, dynamics and connectivity affect colonization–extinction dynamics and the occurrence patterns of a beetle (Stephanopachys linearis), which breeds only in burned trees, existing as dynamic habitat patches that have become rare in managed forest landscapes. We assessed species’ presence/absence twice in all known habitat patches (i.e. > 1 ha sites where forest fires had occurred during the previous 2–15 yr) in a 200 × 150 km region of central Sweden, dominated by managed boreal forest.

Evaluated over six years, the colonization rate was 47% and the local extinction risk was 65%. Probability of colonization increased with patch size (number of suitable trees in a site) and connectivity to occupied patches within 30 km, and decreased with increasing time since fire. Local extinction risk decreased with habitat patch size but increased, unexpectedly, with connectivity. Occurrence increased with patch size and decreased with increasing time since fire. At a regional scale, S. linearis tracks the fire dynamics by colonising sites with burned trees and by becoming extinct at rates which make the species rare at sites where burnt trees are more than eight years old. In managed boreal forest landscapes, a large proportion of sites may be created by prescribed burning (in our study area: 82%), and consequently human decisions strongly affect the future amount of habitat for fire-dependent species and its spatial distribution. Stephanopachys linearis uses burned sites more often if more trees are retained and, to some extent, if sites are concentrated in those parts of a region that already support high population densities of the species.

15 Apr 20:54

Are different facets of plant diversity well protected against climate and land cover changes? A test study in the French Alps

by Wilfried Thuiller, Maya Guéguen, Damien Georges, Richard Bonet, Loïc Chalmandrier, Luc Garraud, Julien Renaud, Cristina Roquet, Jérémie Van Es, Niklaus E. Zimmermann, Sébastien Lavergne

Climate and land cover changes are important drivers of the plant species distributions and diversity patterns in mountainous regions. Although the need for a multifaceted view of diversity based on taxonomic, functional and phylogenetic dimensions is now commonly recognized, there are no complete risk assessments concerning their expected changes. In this paper, we used a range of species distribution models in an ensemble-forecasting framework together with regional climate and land cover projections by 2080 to analyze the potential threat for more than 2500 plant species at high resolution (2.5 × 2.5 km) in the French Alps. We also decomposed taxonomic, functional and phylogenetic diversity facets into α and β components and analyzed their expected changes by 2080. Overall, plant species threats from climate and land cover changes in the French Alps were expected to vary depending on the species' preferred altitudinal vegetation zone, rarity, and conservation status. Indeed, rare species and species of conservation concern were the ones projected to experience less severe change, and also the ones being the most efficiently preserved by the current network of protected areas. Conversely, the three facets of plant diversity were also projected to experience drastic spatial re-shuffling by 2080. In general, the mean α-diversity of the three facets was projected to increase to the detriment of regional β-diversity, although the latter was projected to remain high at the montane-alpine transition zones. Our results show that, due to a high-altitude distribution, the current protection network is efficient for rare species, and species predicted to migrate upward. Although our modeling framework may not capture all possible mechanisms of species range shifts, our work illustrates that a comprehensive risk assessment on an entire floristic region combined with functional and phylogenetic information can help delimitate future scenarios of biodiversity and better design its protection.

15 Apr 20:52

Why do some species have geographically varying responses to fire history?

by D. G. Nimmo, L. T. Kelly, L. M. Farnsworth, S. J. Watson, A. F. Bennett

A capacity to predict the effects of fire on biota is critical for conservation in fire-prone regions as it assists managers to anticipate the outcomes of different approaches to fire management. The task is complicated because species’ responses to fire can vary geographically. This poses challenges, both for conceptual understanding of post-fire succession and fire management. We examine two hypotheses for why species may display geographically varying responses to fire. 1) Species’ post-fire responses are driven by vegetation structure, but vegetation – fire relationships vary spatially (the ‘dynamic vegetation’ hypothesis). 2) Regional variation in ecological conditions leads species to select different post-fire ages as habitat (the ‘dynamic habitat’ hypothesis). Our case study uses data on lizards at 280 sites in a ∼ 100 000 km2 region of south-eastern Australia. We compared the predictive capacity of models based on 1) habitat associations, with models based on 2) fire history and vegetation type, and 3) fire history alone, for four species of lizards. Habitat association models generally out-performed fire history models in terms of predictive capacity. For two species, habitat association models provided good discrimination capacity even though the species showed geographically varying post-fire responses. Our results support the dynamic vegetation hypothesis, that spatial variation in relationships between fire and vegetation structure results in regional variation in fauna–fire relationships. These observations explain how the widely recognised ‘habitat accommodation’ model of animal succession can be conceptually accurate yet predictively weak.

15 Apr 20:52

A species-centered approach for uncovering generalities in organism responses to habitat loss and fragmentation

by Matthew G. Betts, Lenore Fahrig, Adam S. Hadley, Katherine E. Halstead, Jeff Bowman, W. Douglas Robinson, John A. Wiens, David B. Lindenmayer

Theoretical models predict strong influences of habitat loss and fragmentation on species distributions and demography, but empirical studies have shown relatively inconsistent support across species and systems. We argue that species’ responses to landscape-scale habitat loss and fragmentation are likely to appear less idiosyncratic if it is recognized that species perceive the same landscapes in different ways. We present a new quantitative approach that uses species distribution models (SDMs) to measure landscapes (e.g. patch size, isolation, matrix amount) from the perspective of individual species. First, we briefly summarize the few efforts to date demonstrating that once differences in habitat distributions are controlled, consistencies in species’ responses to landscape structure emerge. Second, we present a detailed example providing step-by-step methods for application of a species-centered approach using freely available land-cover data and recent statistical modeling approaches. Third, we discuss pitfalls in current applications of the approach and recommend avenues for future developments. We conclude that the species-centered approach offers considerable promise as a means to test whether sensitivity to habitat loss and fragmentation is mediated by phylogenetic, ecological, and life-history traits. Cross-species generalities in responses to habitat loss and fragmentation will be challenging to uncover unless landscape mosaics are defined using models that reflect differing species-specific distributions, functional connectivity, and domains of scale. The emergence of such generalities would not only enhance scientific understanding of biotic processes driving fragmentation effects, but would allow managers to estimate species sensitivities in new regions.

20 Mar 21:02

Estimating unbiased phenological trends by adapting site-occupancy models

by (Tobias Roth et al)
Ecology, Volume 95, Issue 8, Page 2144-2154, August 2014.
As a response to climate warming, many animals and plants have been found to shift phenologies, such as appearance in spring or timing of reproduction. However, traditional measures for shifts in phenology that are based on observational data likely are biased due to a large influence of population size, observational effort, starting date of a survey, or other causes that may affect the probability of detecting a species. Understanding phenological responses of species to climate change, however, requires a robust measure that could be compared among studies and study years. Here, we developed a new method for estimating arrival and departure dates based on site-occupancy models. Using simulated data, we show that our method provided virtually unbiased estimates of phenological events even if detection probability or the number of sites occupied by the species is changing over time. To illustrate the flexibility of our method, we analyzed spring arrival of two long-distance migrant songbirds and the length of the flight period of two butterfly species, using data from a long-term biodiversity monitoring program in Switzerland. In contrast to many birds that migrate short distances, the two long-distance migrant songbirds tended to postpone average spring arrival by ∼0.5 days per year between 1995 and 2012. Furthermore, the flight period of the short-distance-flying butterfly species apparently became even shorter over the study period, while the flight period of the longer-distance-flying butterfly species remained relatively stable. Our method could be applied to temporally and spatially extensive data from a wide range of monitoring programs and citizen science projects, to help unravel how species and communities respond to global warming.
20 Mar 21:01

Over-invasion by functionally equivalent invasive species

by (James Charles Russell et al)
Ecology, Volume 95, Issue 8, Page 2268-2276, August 2014.
Multiple invasive species have now established at most locations around the world, and the rate of new species invasions and records of new invasive species continue to grow. Multiple invasive species interact in complex and unpredictable ways, altering their invasion success and impacts on biodiversity. Incumbent invasive species can be replaced by functionally similar invading species through competitive processes; however the generalized circumstances leading to such competitive displacement have not been well investigated. The likelihood of competitive displacement is a function of the incumbent advantage of the resident invasive species and the propagule pressure of the colonizing invasive species. We modeled interactions between populations of two functionally similar invasive species and indicated the circumstances under which dominance can be through propagule pressure and incumbent advantage. Under certain circumstances, a normally subordinate species can be incumbent and reject a colonizing dominant species, or successfully colonize in competition with a dominant species during simultaneous invasion. Our theoretical results are supported by empirical studies of the invasion of islands by three invasive Rattus species. Competitive displacement is prominent in invasive rats and explains the replacement of R. exulans on islands subsequently invaded by European populations of R. rattus and R. norvegicus. These competition outcomes between invasive species can be found in a broad range of taxa and biomes, and are likely to become more common. Conservation management must consider that removing an incumbent invasive species may facilitate invasion by another invasive species. Under very restricted circumstances of dominant competitive ability but lesser impact, competitive displacement may provide a novel method of biological control.
20 Mar 21:00

Spatially Explicit Structural Equation Modeling

by (Eric G. Lamb et al)
Ecology, Ahead of Print.
Structural equation modeling (SEM) is a powerful statistical approach for the testing of networks of direct and indirect theoretical causal relationships in complex datasets with intercorrelated dependent and independent variables. SEM is commonly applied in ecology, but the spatial information commonly found in ecological data remains difficult to model in a SEM framework. Here we propose a simple method for spatially explicit SEM (SE-SEM) based on the analysis of variance/covariance matrices calculated across a range of lag distances. This method provides readily interpretable plots of the change in path coefficients across scale and can be implemented using any standard SEM software package. We demonstrate the application of this method using three studies examining the relationships between environmental factors, plant community structure, nitrogen fixation, and plant competition. By design, these datasets had a spatial component, but were previously analyzed using standard SEM models. Using these datasets, we demonstrate the application of SE-SEM to regularly spaced, irregularly spaced, and ad hoc spatial sampling designs and discuss the increased inferential capability of this approach compared with standard SEM. We provide an R package, sesem, to easily implement spatial structural equation modeling.
20 Mar 20:59

The matrix alters the role of path redundancy on patch colonization rates

by (Robert J. Fletcher, Jr. et al)
Ecology, Volume 95, Issue 6, Page 1444-1450, June 2014.
Landscape connectivity is central to many problems in ecology and conservation. Recently, the role of path redundancies on movement of organisms has been emphasized for understanding connectivity, because increasing the number of potential paths (i.e., redundancy) is predicted to increase movement rates, which can alter predictions for foraging theory and population dynamics. Nonetheless, experiments that test for the effects of path redundancies on connectivity remain scarce. We tested for the role of path redundancies on the movements of a habitat specialist, Chelinidea vittiger, using experimental arenas that altered path redundancy by varying the amount and configuration of stepping stones across a gradient of matrix resistance. We found that stepping-stone redundancies increased colonization rates to target patches, but the effects differed depending on the configuration of redundancy and the structure of the matrix. In addition, matrix effects were better explained through the use of effective distance measures that incorporate redundancy in the matrix than those that ignore redundancy. Our results provide experimental evidence that measures that ignore redundancies may be inadequate for capturing functional connectivity, illustrate the ways in which redundancies alter colonization rates, and emphasize how habitat configuration and matrix structure can interact to guide movement of individuals across landscapes.
20 Mar 20:59

A mechanistic–bioclimatic modeling analysis of the potential impact of climate change on biomes of the Tibetan Plateau

by (Jian-Sheng Ye et al)
Ecology, Volume 95, Issue 8, Page 2109-2120, August 2014.
The Tibetan Plateau (TP) is experiencing high rates of climatic change. We present a novel combined mechanistic–bioclimatic modeling approach to determine how changes in precipitation and temperature on the TP may impact net primary production (NPP) in four major biomes (forest, shrub, grass, desert) and if there exists a maximum rain use efficiency (RUEMAX) that represents Huxman et al.'s “boundary that constrain[s] site-level productivity and efficiency.” We used a daily mechanistic ecosystem model to generate 40-yr outputs using observed climatic data for scenarios of decreased precipitation (25–100%); increased air temperature (1°–6°C); simultaneous changes in both precipitation (±50%, ±25%) and air temperature (+1 to +6°C) and increased interannual variability (IAV) of precipitation (+1σ to +3σ, with fixed means, where σ is SD). We fitted model output from these scenarios to Huxman et al.'s RUEMAX bioclimatic model, NPP = α + RUE × PPT (where α is the intercept, RUE is rain use efficiency, and PPT is annual precipitation). Based on these analyses, we conclude that there is strong support (when not explicit, then trend-wise) for Huxman et al.'s assertion that biomes converge to a common RUEMAX during the driest years at a site, thus representing the boundary for highest rain use efficiency; the interactive effects of simultaneously decreasing precipitation and increasing temperature on NPP for the TP is smaller than might be expected from additive, single-factor changes in these drivers; and that increasing IAV of precipitation may ultimately have a larger impact on biomes of the Tibetan Plateau than changing amounts of rainfall and air temperature alone.
20 Mar 20:58

P values are only an index to evidence: 20th- vs. 21st-century statistical science

by (K. P. Burnham et al)
Ecology, Volume 95, Issue 3, Page 627-630, March 2014.
20 Mar 20:58

P values, hypothesis testing, and model selection: it's déjà vu all over again

by (Aaron M. Ellison et al)
Ecology, Volume 95, Issue 3, Page 609-610, March 2014.
18 Mar 07:43

Matching trends between recent distributional changes of northern-boreal birds and species-climate model predictions

Publication date: April 2014
Source:Biological Conservation, Volume 172
Author(s): Raimo Virkkala , Risto K. Heikkinen , Aleksi Lehikoinen , Jari Valkama
Species inhabiting high-latitude environments are anticipated to be exceptionally vulnerable to climate change because of the greater temperature increases projected for these regions. Earlier studies based on bioclimatic envelope models and bird atlas data from 1974 to 1989 have suggested that northern-boreal bird species may face considerable range contractions in Northern Europe by 2080. Using new bird atlas data from Finland compiled in 2006–2010, we show that the ranges of these northern-boreal bird species have already contracted by 27%, on average, compared with 1974–89. The majority (21) of the studied 27 northern-boreal bird species showed significant contractions of ranges and/or northwards shifts. Thus the range changes of northern species are in the same direction as the predictions of species-climate change models.

18 Mar 07:42

Birds protected by national legislation show improved population trends in Eastern Europe

Publication date: April 2014
Source:Biological Conservation, Volume 172
Author(s): Jaroslav Koleček , Matthias Schleuning , Ian J. Burfield , András Báldi , Katrin Böhning-Gaese , Vincent Devictor , José María Fernández-García , David Hořák , Chris A.M. Van Turnhout , Oksana Hnatyna , Jiří Reif
Protecting species is one of the major focuses of conservation efforts. However, large-scale assessments of the effects of species protection on animal populations are rare. Protection has been shown to benefit birds in Western Europe and in the United States, but not yet in Eastern Europe, where modern environmental legislation was only established in the early 1990s after political changes. We compared the population trends of bird species between 1970–1990 and 1990–2000 in ten Eastern European countries for species protected since 1990s and unprotected species, controlling for effects of species’ phylogeny and traits. After 1990, trends in protected species improved more than in unprotected species. This suggests that national legislation has helped prevent declines of the protected species, although there was a high variability in population trends among countries. In particular, there was great improvement in the population trends of protected species in countries providing ‘narrow and deep’ protection to few species. In contrast, trends of protected species remained nearly unchanged in countries providing ‘broad and shallow’ protection to most species, while few unprotected species had adverse population trends in these countries. Although our correlative analysis cannot show causal relationships, the positive relationship between protection and long-term population trends suggests that species protection is a highly relevant tool for conservation. A combination of ‘broad and shallow’ and ‘narrow and deep’ protection might be most efficient for securing healthy bird populations for the future.

17 Mar 22:41

Foraging guild perturbations and ecological homogenization driven by a despotic native bird species

by Alison Howes, Ralph Mac Nally, Richard Loyn, Jarrod Kath, Michiala Bowen, Clive McAlpine, Martine Maron

Anthropogenic activities often cause specialized and fragmentation-sensitive species to be replaced by competitive commensal or invasive species, resulting in reduced diversity and biotic homogenization. However, biotic homogenization driven by increased dominance of a native species has rarely been investigated. Increased abundance of competitive species can have important consequences for assemblage dynamics including homogenization of foraging strategies and, potentially, ecological services. This study assesses how changes to bird assemblages due to the occurrence of an aggressive honeyeater alter the foraging profiles of avifauna in 400 woodland sites in nine study regions across eastern Australia, and explores the potential implications for ecological services. We compared beta diversity among sites with a high and low abundance of the aggressive Noisy Miner Manorina melanocephala. Shifts in ecological characteristics of bird assemblages of sites with high and low abundance of Noisy Miners, including mean and variation in niche position, bill length and body size, were explored. Sites with a high abundance of Noisy Miners were more taxonomically and ecologically homogeneous and had fewer species than sites with a low abundance of Noisy Miners. The mean niche positions of bird assemblages changed and were increasingly dominated by larger vertebrate feeders, granivores and frugivores as Noisy Miner abundance increased. The mean body size and bill length of the insectivore species present at a site increased with Noisy Miner abundance. This change in the bird community along with reduced diversity in foraging strategies implies a loss of the ecological functions provided by smaller-bodied species, potentially affecting plant dispersal and regeneration, insect herbivory and ultimately woodland resilience. Our study demonstrates a substantial shift in ecological profile over a broad geographical area as a result of a single native species.

17 Mar 22:40

Testing multiple pathways for impacts of the non-native Black-headed Weaver Ploceus melanocephalus on native birds in Iberia in the early phase of invasion

by James P. B. Grundy, Aldina M. A. Franco, Martin J. P. Sullivan

Not all non-native species have strong negative impacts on native species. It is desirable to assess whether a non-native species will have a negative impact at an early stage in the invasion process, when management options such as eradication are still available. Although it may be difficult to detect early impacts of non-native species, it is necessary to ensure that management decisions can be based on case-specific scientific evidence. We assess the impacts of a non-native bird, the Black-headed Weaver Ploceus melanocephalus, at an early stage in its invasion of the Iberian Peninsula. To do this we identify potential pathways by which competition for shared resources by Black-headed Weavers could lead to population declines in two ecologically similar native species, and generate hypotheses to test for evidence of competition along these pathways. Black-headed Weavers could potentially impact native species by displacing them from nesting habitat, or by reducing habitat quality. We found no evidence for either potential competition pathway, suggesting that Black-headed Weavers do not currently compete with the two native species. However, it is possible that mechanisms that currently allow coexistence may not operate once Black-headed Weavers reach higher population densities or different habitats.

04 Mar 21:43

Extinctions and the loss of ecological function in island bird communities

by Alison G. Boyer, Walter Jetz



Because of the negative impact that ongoing biodiversity loss may have on ecosystem properties that are critical for humans, understanding the relationship between extinction and functional diversity over time is of critical importance for conservation. However, empirical evidence concerning the sensitivity of vertebrate community function to species loss is very limited. Here we assess documented prehistoric and historic extinctions of birds on Pacific islands in an effort to quantify the consequences of extinctions for functional structure and diversity in natural communities over broad spatial scales.


Forty-four islands from across the Pacific.


We estimated functional aspects of island bird communities before and after Holocene extinctions based on body size, foraging niche, diet and activity period. We used four separate metrics to measure ecological function: functional diversity (FD), functional richness (FRic), functional evenness and functional divergence. We employed null models to separate the effects of observed extinctions from changes expected due to declining species richness.


We find that Holocene bird extinctions led to substantial changes in community-level functional diversity. Observed declines in FD and FRic were predictable from the pre-extinction composition of communities, and did not differ from null model expectations. Across all islands, we observed non-random changes in functional trait composition, with shifts away from ground-level foraging, granivory and herbivory after extinctions. Extinctions have resulted in the loss of up to 80% of original functional diversity on some islands and caused a sharp decrease in the variety of ecological functions provided by birds.

Main conclusions

Our findings illustrate the significant losses of functional diversity that are already taking place on many islands and demonstrate its close connection with the loss of species. Accounting for the functional roles of species allows a more integrative understanding of ecological function and helps to bridge species and ecosystem perspectives in conservation science.

04 Mar 21:43

Measuring and explaining large-scale distribution of functional and phylogenetic diversity in birds: separating ecological drivers from methodological choices

by Sarah Calba, Virginie Maris, Vincent Devictor



Investigations into how different facets of biodiversity are related has become a central research agenda in ecology. Here, we use a large-scale and high-resolution data set on bird distribution to examine the robustness of the relationships between species diversity and functional or phylogenetic diversity.




We measured the functional and phylogenetic diversity of 1914 bird assemblages monitored over 10 years with a standardized protocol. We investigated the consequences of incorporating abundance versus presence–absence data, changing the number and identity of traits considered, or varying the spatial scale used to estimate functional and phylogenetic diversity. We further examined the outcomes of different null model procedures that aim to reveal ecological processes influencing the distribution of each facet of diversity.


We found that the shape and strength of the relationship between species diversity and functional diversity are structured by several methodological choices. We show that increasing the quantity of information yielded by the indices (in particular, including abundances or increasing the number of traits considered) decreases the amount of functional redundancy estimated. Reducing the number of functional traits used to estimate functional diversity can change and even reverse the relationship of interest. Moreover, using alternative null models, we highlighted the specific role of environmental filtering and the link between species abundances and their functional originality (defined for a given species as the average of the functional distances with other species). The same tests applied to phylogenetic diversity revealed that its relationship with species diversity varies differently suggesting that this latter index cannot be used as a proxy for functional diversity.

Main conclusions

Our results show that the identification of patterns and processes linking species diversity to functional or phylogenetic diversity vary with methodological choices. We further show that the study of these sources of variation via robustness tests allows ecologically meaningful information to be separated from pure artefacts.

04 Mar 21:42

Life history and spatial traits predict extinction risk due to climate change

by Richard G. Pearson

Climate change could be a game-changer for biodiversity conservation, potentially invalidating many established methods including those employed in vulnerability assessments. Now, a simulation study finds that extinction risk due to climate change can be predicted using measurable spatial and demographic variables. Interestingly, most of those variables identified as important are already used in species conservation assessment.

Nature Climate Change 4 217 doi: 10.1038/nclimate2113

04 Mar 21:42

Biodiversity: Predictive traits to the rescue

by Antoine Guisan

Climate change poses new challenges to the conservation of species, which at present requires data-hungry models to meaningfully anticipate future threats. Now a study suggests that species traits may offer a simpler way to help predict future extinction risks.

Nature Climate Change 4 175 doi: 10.1038/nclimate2157

04 Mar 21:41

Defining extreme wildland fires using geospatial and ancillary metrics

by Karen O. Lannom
Karen O. Lannom, Wade T. Tinkham, Alistair M.S. Smith, John Abatzoglou, Beth A. Newingham, Troy E. Hall, Penelope Morgan, Eva K. Strand, Travis B. Paveglio, John W. Anderson, Aaron M. Sparks

This study explores four metrics to describe both widespread fire years and potentially extreme individual fires derived from a case study of wildland fires from 1984 to 2009 in the north-western United States. A combination of percentile-based thresholds is used for each of the metrics to define individual fires as extreme events.

03 Mar 21:25

Impact of Phytophthora-dieback on birds in Banksia woodlands in south west Western Australia

Publication date: March 2014
Source:Biological Conservation, Volume 171
Author(s): Robert A. Davis , Leonie E. Valentine , Michael D. Craig , Barbara Wilson , Wesley J. Bancroft , Marnie Mallie
Invasive plant pathogens have impacted forest and woodland systems globally and can negatively impact biodiversity. The soil-borne plant pathogen Phytophthora cinnamomi is listed as one of the world’s worst invasive species and alters plant community composition and habitat structure. Few studies have examined how these Phytophthora-induced habitat changes affect faunal communities. We examined bird communities in Banksia woodland with, and without, Phytophthora dieback in a biodiversity hotspot, southwestern Australia. Seven sites along dieback fronts, with paired 1-ha plots in diseased and healthy vegetation, were surveyed monthly for birds over seven months. Vegetation assessments showed that diseased sites had reduced plant species richness, litter, shrub, tree and canopy cover, high bare ground and significantly lower flowering scores, than healthy sites. Bird community composition differed significantly between diseased and healthy sites, although total bird abundance, total species richness and foraging guilds, did not. Average species richness of birds per survey and the abundance of brown honeyeaters, western spinebills and silvereyes was lower in diseased than healthy sites. The tawny-crowned honeyeater had higher abundances in diseased sites. Similarity matrices of habitat structure, flowering scores and bird assemblages were congruent, indicating that habitat structural differences were influencing bird community composition. Our results suggest that this pathogen is potentially a serious threat to avian biodiversity and especially for nectarivores, and populations in fragmented landscapes. Since elimination of the pathogen is not currently possible, management should focus on methods of preventing its spread until techniques to eliminate the pathogen are developed.

03 Mar 21:25

Evaluating empirical evidence for decline in temperate woodland birds: A nationally threatened assemblage of species

Publication date: March 2014
Source:Biological Conservation, Volume 171
Author(s): Laura Rayner , David B. Lindenmayer , Philip Gibbons , Adrian D. Manning
Quantifying the population trends of species is crucial to achieving effective conservation action. However, deriving accurate and reliable indices of change is difficult due to the paucity and complexity of population data. There is a growing need to assess the inferential status of reported trend estimates given their pertinence to evidence-based conservation policy and funding. In this review, we used a simple scoring system to assess the rigour of population assessments using Australian temperate woodland birds as a case study. These birds are widely considered to be in severe and ongoing decline at a national scale. However, we found relatively few studies that report population trends for woodland birds in the existing conservation literature (44 articles, 9% of total) and only 33 articles (7% of total) that actually attempt to measure change using population data. While we identified strong signs that the inferential status of population research on temperate woodland birds is improving, we detected serious limitations in the temporal coverage and statistical analysis of population data used in the majority (80%) of trend assessments, compromising any long-term inference about population persistence. Despite these limitations, the decline of woodland birds is referenced in over half of all Australian woodland bird conservation studies (53%), with most of the information on woodland bird status (49% of citations) sourced from relatively few, predominantly qualitative, studies of change. The paucity of research that can reliably detect trends to draw conclusions about species persistence is a concerning issue for conservation practitioners and policy makers.

03 Mar 21:23

Not all green is as good: Different effects of the natural and cultivated components of urban vegetation on bird and butterfly diversity

Publication date: March 2014
Source:Biological Conservation, Volume 171
Author(s): Kwek Yan Chong , Siyang Teo , Buddhima Kurukulasuriya , Yi Fei Chung , Subaraj Rajathurai , Hugh Tiang Wah Tan
It has been suggested that provision of greenery can ameliorate the hostility of the urban environment for wildlife, but greenery can either be in the form of regenerating or remnant patches of natural vegetation, or as cultivated tree, shrub, and ground cover. We test if natural and cultivated greenery differed in their effects on bird and butterfly diversity in the tropical city-state of Singapore, while accounting for the effects of traffic density. Natural vegetation cover was positively correlated to both bird and butterfly species richness. Cultivated tree cover was positively correlated to bird species richness. Meanwhile, ground cover was weakly negatively correlated to bird species richness and overall cultivated greenery cover was weakly positively correlated to butterfly species richness. Increasing road lane density also negatively impacted both bird and butterfly species richness, while there was substantial evidence for an interaction effect between road lane density and cultivated tree cover on bird species richness. Cultivated and natural forms of greenery favoured different assemblages of bird and butterfly species. After controlling for the confounding effects of alpha diversity on community dissimilarity, cultivated greenery was found to produce homogeneous bird and butterfly communities in the urban landscape. Therefore, not all forms of greenery benefit urban biodiversity to the same extent. Management of urban areas to support bird and butterfly wildlife would need to maximise natural or semi-natural cover and only resort to highly-manicured, artificial greenery as a second option, while planning road networks carefully to optimize road lane density.

03 Mar 21:22

Global Urban Biodiversity

by Aronson, M. F. J., La Sorte, F. A., Nilon, C. H., Katti, M., Goddard, M. A., Lepczyk, C. A., Warren, P. S., Williams, N. S. G., Cilliers, S., Clarkson, B., Dobbs, C., Dolan, R., Hedblom, M., Klotz, S., Kooijmans, J. L., Kuhn, I., MacGregor-Fors, I., McDonnell, M., Mortberg, U., Pysek, P., Siebert, S., Sushinsky, J., Werner, P., Winter, M.

Urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. However, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. Here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). We found that the majority of urban bird and plant species are native in the world's cities. Few plants and birds are cosmopolitan, the most common being Columba livia and Poa annua. The density of bird and plant species (the number of species per km2) has declined substantially: only 8% of native bird and 25% of native plant species are currently present compared with estimates of non-urban density of species. The current density of species in cities and the loss in density of species was best explained by anthropogenic features (landcover, city age) rather than by non-anthropogenic factors (geography, climate, topography). As urbanization continues to expand, efforts directed towards the conservation of intact vegetation within urban landscapes could support higher concentrations of both bird and plant species. Despite declines in the density of species, cities still retain endemic native species, thus providing opportunities for regional and global biodiversity conservation, restoration and education.

03 Mar 21:21

Guidance for marine spatial planning

by Rassweiler, A., Costello, C., Hilborn, R., Siegel, D. A.

Marine spatial planning (MSP), whereby areas of the ocean are zoned for different uses, has great potential to reduce or eliminate conflicts between competing management goals, but only if strategically applied. The recent literature overwhelmingly agrees that including stakeholders in these planning processes is critical to success; but, given the countless alternative ways even simple spatial regulations can be configured, how likely is it that a stakeholder-driven process will generate plans that deliver on the promise of MSP? Here, we use a spatially explicit, dynamic bioeconomic model to show that stakeholder-generated plans are doomed to fail in the absence of strong scientific guidance. While strategically placed spatial regulations can improve outcomes remarkably, the vast majority of possible plans fail to achieve this potential. Surprisingly, existing scientific rules of thumb do little to improve outcomes. Here, we develop an alternative approach in which models are used to identify efficient plans, which are then modified by stakeholders. Even if stakeholders alter these initial proposals considerably, results hugely outperform plans guided by scientific rules of thumb. Our results underscore the importance of spatially explicit dynamic models for the management of marine resources and illustrate how such models can be harmoniously integrated into a stakeholder-driven MSP process.

12 Feb 03:04

Modeling Wildfire Incident Complexity Dynamics

by Matthew P. Thompson

by Matthew P. Thompson

Wildfire management in the United States and elsewhere is challenged by substantial uncertainty regarding the location and timing of fire events, the socioeconomic and ecological consequences of these events, and the costs of suppression. Escalating U.S. Forest Service suppression expenditures is of particular concern at a time of fiscal austerity as swelling fire management budgets lead to decreases for non-fire programs, and as the likelihood of disruptive within-season borrowing potentially increases. Thus there is a strong interest in better understanding factors influencing suppression decisions and in turn their influence on suppression costs. As a step in that direction, this paper presents a probabilistic analysis of geographic and temporal variation in incident management team response to wildfires. The specific focus is incident complexity dynamics through time for fires managed by the U.S. Forest Service. The modeling framework is based on the recognition that large wildfire management entails recurrent decisions across time in response to changing conditions, which can be represented as a stochastic dynamic system. Daily incident complexity dynamics are modeled according to a first-order Markov chain, with containment represented as an absorbing state. A statistically significant difference in complexity dynamics between Forest Service Regions is demonstrated. Incident complexity probability transition matrices and expected times until containment are presented at national and regional levels. Results of this analysis can help improve understanding of geographic variation in incident management and associated cost structures, and can be incorporated into future analyses examining the economic efficiency of wildfire management.
12 Feb 03:04

Optimization of Landscape Services under Uncoordinated Management by Multiple Landowners

by Miguel Porto et al.

by Miguel Porto, Otília Correia, Pedro Beja

Landscapes are often patchworks of private properties, where composition and configuration patterns result from cumulative effects of the actions of multiple landowners. Securing the delivery of services in such multi-ownership landscapes is challenging, because it is difficult to assure tight compliance to spatially explicit management rules at the level of individual properties, which may hinder the conservation of critical landscape features. To deal with these constraints, a multi-objective simulation-optimization procedure was developed to select non-spatial management regimes that best meet landscape-level objectives, while accounting for uncoordinated and uncertain response of individual landowners to management rules. Optimization approximates the non-dominated Pareto frontier, combining a multi-objective genetic algorithm and a simulator that forecasts trends in landscape pattern as a function of management rules implemented annually by individual landowners. The procedure was demonstrated with a case study for the optimum scheduling of fuel treatments in cork oak forest landscapes, involving six objectives related to reducing management costs (1), reducing fire risk (3), and protecting biodiversity associated with mid- and late-successional understories (2). There was a trade-off between cost, fire risk and biodiversity objectives, that could be minimized by selecting management regimes involving ca. 60% of landowners clearing the understory at short intervals (around 5 years), and the remaining managing at long intervals (ca. 75 years) or not managing. The optimal management regimes produces a mosaic landscape dominated by stands with herbaceous and low shrub understories, but also with a satisfactory representation of old understories, that was favorable in terms of both fire risk and biodiversity. The simulation-optimization procedure presented can be extended to incorporate a wide range of landscape dynamic processes, management rules and quantifiable objectives. It may thus be adapted to other socio-ecological systems, particularly where specific patterns of landscape heterogeneity are to be maintained despite imperfect management by multiple landowners.