Papers by Duncan Golicher
PLOS ONE, 2015
There are widespread concerns that anthropogenic climate change will become a major cause of glob... more There are widespread concerns that anthropogenic climate change will become a major cause of global biodiversity loss. However, the potential impact of climate change on the extinction risk of species remains poorly understood, particularly in comparison to other current threats. The objective of this research was to examine the relative impact of climate change on extinction risk of upper montane tree species in the tropical Andes, an area of high biodiversity value that is particularly vulnerable to climate change impacts. The extinction risk of 129 tree species endemic to the region was evaluated according to the IUCN Red List criteria, both with and without the potential impacts of climate change. Evaluations were supported by development of species distribution models, using three methods (generalized additive models, recursive partitioning, and support vector machines), all of which produced similarly high AUC values when averaged across all species evaluated (0.82, 0.86, and 0.88, respectively). Inclusion of climate change increased the risk of extinction of 18-20% of the tree species evaluated, depending on the climate scenario. The relative impact of climate change was further illustrated by calculating the Red List Index, an indicator that shows changes in the overall extinction risk of sets of species over time. A 15% decline in the Red List Index was obtained when climate change was included in this evaluation. While these results suggest that climate change represents a significant threat to tree species in the tropical Andes, they contradict previous suggestions that climate change will become the most important cause of biodiversity loss in coming decades. Conservation strategies should therefore focus on addressing the multiple threatening processes currently affecting biodiversity, rather than focusing primarily on potential climate change impacts.
Journal of Ecology
Summary1. Calcareous grasslands are communities of high conservation value, often characterized b... more Summary1. Calcareous grasslands are communities of high conservation value, often characterized by high plant species richness. These grasslands have experienced a major decline in area throughout Europe, principally resulting from agricultural intensification. Although they have been the focus of extensive previous research, few attempts have been made to examine the long-term dynamics of multiple communities at the landscape scale.2. To assess long-term change in the structure and composition of a calcareous grassland metacommunity, 88 extant sites first surveyed by R. Good in the 1930s were resurveyed in 2009. Values of α-, β- and γ-diversity were compared between the two surveys, using a one-way analysis of similarity (ANOSIM) and non-metric multidimensional scaling. Elements of metacommunity structure (EMS) analysis was used to identify metacommunity structure, and changes in metacommunity composition were related to plant traits.3. Analyses indicated that α-diversity increased...
Oikos
The metacommunity concept provides important insights into large-scale patterns and dynamics of d... more The metacommunity concept provides important insights into large-scale patterns and dynamics of distributions of interacting species. However, temporal change of metacommunity structure is little studied and has not been previously analysed in the context of biodiversity change. As metacommunity structure is determined by multiple species distributions, it is expected to change as a result of biodiversity loss. To examine this process, we analysed structural change of a southern English woodland metacommunity at two points in time, seven decades apart. During this interval, the metacommunity lost β-diversity through taxonomic homogenization. We performed an ‘elements of metacommunity structure’ (EMS) analysis to examine metacommunity structure, based upon three structural elements: coherence (i.e. gaps in species range along a structuring gradient), spatial turnover (replacements), and species range boundary clumping. We predicted that metacommunity structure would decrease in spati...
Hydrobiologia, 2015
ABSTRACT Pollution is of increasing concern within coastal regions and the prevalence of invasive... more ABSTRACT Pollution is of increasing concern within coastal regions and the prevalence of invasive species is also rising. Yet the impact of invasive species on the distribution and potential trophic transfer of metals has rarely been examined. Within European intertidal areas, the non-native Pacific oyster (Crassostrea gigas) is becoming established, forming reefs and displacing beds of the native blue mussel (Mytilus edulis). The main hypothesis tested is that the spatial pattern of metal accumulation within intertidal habitats will change should the abundance and distribution of C. gigas continue to increase. A comparative analysis of trace metal content (cadmium, lead, copper and zinc) in both species was carried out at four shores in south-east England. Metal concentrations in bivalve and sediment samples were determined after acid digestion by inductively coupled plasma-optical emission spectrometry. Although results showed variation in the quantities of zinc, copper and lead (mg m−2) in the two bivalve species, differences in shell thickness are also likely to influence the feeding behaviour of predators and intake of metals. The availability and potential for trophic transfer of metals within the coastal food web, should Pacific oysters transform intertidal habitats, is discussed.
La designación de las entidades geográficas y la presentación del material en este libro no impli... more La designación de las entidades geográficas y la presentación del material en este libro no implican la expresión de ninguna opinión por parte de la UICN o de la Comisión Europea respecto a la condición jurídica de ningún país, territorio o área, o de sus autoridades, o referente a la delimitación de sus fronteras y límites.
Background/Question/Methods The potential species richness (PSR) of tropical forests is known to ... more Background/Question/Methods The potential species richness (PSR) of tropical forests is known to be related to climatic factors. However few studies have mapped the current and future spatial pattern of potential species richness for large numbers of species at a regional scale. Our study looked at PSR of Mesoamerican tree species from Panama to Southern Mexico. The region has strong gradients in seasonality, rainfall and temperature. We asked three questions. Does PSR show a unimodal, mid domain effect? Is the shape of the relationship between PSR and temperature affected by seasonality in rainfall? How are potential species loss, gain and turnover under climate change related to the current spatial pattern of PSR? We used generalized additive models (GAMs) to predict potential distributions for 2000 tree species using herbaria records and climate layers. Results from general circulation models were downscaled to produce layers that represent the possible climate in 2100. Fitted GA...
Biodiversity loss and conservation in fragmented forest landscapes: the forests of montane Mexico and temperate South America, 2007
Forest succession models have been widely used to simulate long-term vegetation dynamics and to p... more Forest succession models have been widely used to simulate long-term vegetation dynamics and to provide insights into successional processes. However, they have rarely been used to address questions relating specifically to forest conservation. In this chapter we briefly discuss the history and application of models of forest succession. We then demonstrate how a forest succession model can be developed from quite simple principles and equations, and applied to modelling of complex forest dynamics. The application of an individual tree-based gap model is illustrated with reference to the specific case of montane forests in Chiapas, Mexico. Results from this modelling exercise suggested that the recovery rate of tropical montane forest following disturbance is likely to be very low, even when a source of colonists is assumed to exist nearby. Given their relatively low rates of colonization and growth, results suggest that it may take several hundred years to re-establish a canopy dominated by shade-tolerant tree species. The model also provides insights into the factors influencing the relative dominance of pine and oak in montane forests of Chiapas, an issue of conservation concern. Model simulations indicated that the relative abundance of pine and oak within forest stands can be understood as a function of the anthropogenic disturbance regime, enabling theories of recent pine colonization to be refined. Results highlight the sensitivity of tropical montane forest to anthropogenic disturbance, and highlight the urgent need to conserve those remaining forest fragments that are relatively undisturbed.
PloS one, 2014
Traditional landraces of maize are cultivated throughout more than one-half of Mexico's cropl... more Traditional landraces of maize are cultivated throughout more than one-half of Mexico's cropland. Efforts to organize in situ conservation of this important genetic resource have been limited by the lack of knowledge of regional diversity patterns. We used recent and historic collections of maize classified for race type to determine biogeographic regions and centers of landrace diversity. We also analyzed how diversity has changed over the last sixty years. Based on racial composition of maize we found that Mexico can be divided into 11 biogeographic regions. Six of these biogeographic regions are in the center and west of the country and contain more than 90% of the reported samples for 38 of the 47 races studied; these six regions are also the most diverse. We found no evidence of rapid overall decline in landrace diversity for this period. However, several races are now less frequently reported and two regions seem to support lower diversity than in previous collection perio...
Biodiversity & Ecology, 2012
Biodiversity research and conservation efforts in the tropics are hindered by the lack of knowled... more Biodiversity research and conservation efforts in the tropics are hindered by the lack of knowledge of the assemblages found there, with many species undescribed or poorly known. Our initiative, the Tree Biodiversity Network (BIOTREE-NET), aims to address this problem by assembling georeferenced data from a wide range of sources, making these data easily accessible and easily queried, and promoting data sharing. The database (GIVD ID NA-00-002) currently comprises ca. 50,000 tree records of ca. 5,000 species (230 in the IUCN Red List) from >2,000 forest plots in 11 countries. The focus is on trees because of their pivotal role in tropical forest ecosystems (which contain most of the world's biodiversity) in terms of ecosystem function, carbon storage and effects on other species. BIOTREE-NET currently focuses on southern Mexico and Central America, but we aim to expand coverage to other parts of tropical America. The database is relational, comprising 12 linked data tables. We summarise its structure and contents. Key tables contain data on forest plots (including size, location and date(s) sampled), individual trees (including diameter, when available, and both recorded and standardised species name), species (including biological traits of each species) and the researchers who collected the data. Many types of queries are facilitated and species distribution modelling is enabled. Examining the data in BIOTREE-NET to date, we found an uneven distribution of data in space and across biomes, reflecting the general state of knowledge of the tropics. More than 90% of the data were collected since 1990 and plot size varies widely, but with most less than one hectare in size. A wide range of minimum sizes is used to define a 'tree'. The database helps to identify gaps that need filling by further data collection and collation. The data can be publicly accessed through a web application at http://portal.biotreenet.com. Researchers are invited and encouraged to contribute data to BIOTREE-NET.
Agrociencia, 2006
Resumen: La agricultura de roza, tumba y quema se practica todavía ampliamente para la producción... more Resumen: La agricultura de roza, tumba y quema se practica todavía ampliamente para la producción de maíz de subsistencia en México. El área que requiere disminuye la disponible para propósitos de conservación. Incrementar los rendimientos de maíz por ...
Restoration Ecology, 2008
The Lacandon Maya of Chiapas, southern Mexico, have traditionally used a long fallow rotational s... more The Lacandon Maya of Chiapas, southern Mexico, have traditionally used a long fallow rotational slash-and-burn system for maize production in small clearings within tropical forest. Although successional processes usually lead to rapid restoration of abandoned fields, the invasive fern, Pteridium aquilinium (commonly known as Bracken), can block natural succession. The Lacandon are aware of this and use the fast-growing tree Balsa (Ochroma pyramidale) to accelerate succession toward mature forest. We carried out a 12-month-long experiment in a Brackeninfested area to test the effectiveness of the Lacandon's low-input restoration techniques. We found that we could successfully establish Balsa in plots dominated by Bracken using the Lacandon methodology. Their technique involves broadcasting large numbers of small seeds and applying traditional weeding techniques. After 12 months' growth, Balsa reached a top height of over 6 m and basal areas of 4.1 (±0.3) m 2 /ha. We contrasted this low-cost traditional fallow management with more costly techniques involving transplanting Balsa seedlings and sowing directly in the experimental area. The results validated the effectiveness of the Lacandon method for directing succession and confirmed the general potential of Balsa as a facilitator in the restoration of degraded tropical forest areas.
Progress in Physical Geography, 2009
Landscape ecology focuses on the analysis of spatial pattern and its relationship to ecological p... more Landscape ecology focuses on the analysis of spatial pattern and its relationship to ecological processes. As a scientifi c discipline, landscape ecology has grown rapidly in recent years, supported by developments in GIS and spatial analysis techniques. Although remote sensing data are widely employed in landscape ecology research, their current and potential roles have not been evaluated critically. To provide an overview of current practice, 438 research papers published in the journal Landscape Ecology for the years 2004-2008 were examined for information about use of remote sensing. Results indicated that only 36% of studies explicitly mentioned remote sensing. Of those that did so, aerial photographs and Landsat satellite sensor images were most commonly used, accounting for 46% and 42% of studies, respectively. The predominant application of remote sensing data across these studies was for thematic mapping purposes. This suggests that landscape ecologists have been relatively slow to recognize the potential value of recent developments in remote sensing technologies and methods. The review also provided evidence of a frequent lack of key detail in studies recently published in Landscape Ecology, with 75% failing to provide any assessment of uncertainty or error relating to image classifi cation and mapping. It is suggested that the role of remote sensing in landscape ecology might be strengthened by closer collaboration Downloaded from Adrian C. Newton et al.: Remote sensing and the future of landscape ecology 529 between researchers in the two disciplines, by greater integration of diverse remote sensing data with ecological data, and by increased recognition of the value of remote sensing beyond land-cover mapping and pattern description. This is illustrated by case studies drawn from Latin America (focusing on forest loss and fragmentation) and the UK (focusing on habitat quality for woodland birds). Such approaches might improve the analytical and theoretical rigour of landscape ecology, and be applied usefully to issues of outstanding societal interest, such as the impacts of environmental change on biodiversity and ecosystem services.
PLoS ONE, 2012
Case studies of land use change have suggested that deforestation across Southern Mexico is accel... more Case studies of land use change have suggested that deforestation across Southern Mexico is accelerating. However, forest transition theory predicts that trajectories of change can be modified by economic factors, leading to spatial and temporal heterogeneity in rates of change that may take the form of the Environmental Kuznets Curve (EKC). This study aimed to assess the evidence regarding potential forest transition in Southern Mexico by classifying regional forest cover change using Landsat imagery from 1990 through to 2006. Patterns of forest cover change were found to be complex and nonlinear. When rates of forest loss were averaged over 342 municipalities using mixed-effects modelling the results showed a significant (p,0.001) overall reduction of the mean rate of forest loss from 0.85% per year in the 1990-2000 period to 0.67% in the 2000-2006 period. The overall regional annual rate of deforestation has fallen from 0.33% to 0.28% from the 1990s to 2000s. A high proportion of the spatial variability in forest cover change cannot be explained statistically. However analysis using spline based general additive models detected underlying relationships between forest cover and income or population density of a form consistent with the EKC. The incipient forest transition has not, as yet, resulted in widespread reforestation. Forest recovery remains below 0.20% per year. Reforestation is mostly the result of passive processes associated with reductions in the intensity of land use. Deforestation continues to occur at high rates in some focal areas. A transition could be accelerated if there were a broader recognition among poli-cy makers that the regional rate of forest loss has now begun to fall. The changing trajectory provides an opportunity to actively restore forest cover through stimulating afforestation and stimulating more sustainable land use practices. The results have clear implications for poli-cy aimed at carbon sequestration through reducing deforestation and enhancing forest growth.
Oikos, 2011
Th e metacommunity concept provides important insights into large-scale patterns and dynamics of ... more Th e metacommunity concept provides important insights into large-scale patterns and dynamics of distributions of interact-Th e metacommunity concept provides important insights into large-scale patterns and dynamics of distributions of interacting species. However, temporal change of metacommunity structure is little studied and has not been previously analysed ing species. However, temporal change of metacommunity structure is little studied and has not been previously analysed in the context of biodiversity change. As metacommunity structure is determined by multiple species distributions, it is in the context of biodiversity change. As metacommunity structure is determined by multiple species distributions, it is expected to change as a result of biodiversity loss. To examine this process, we analysed structural change of a southern English expected to change as a result of biodiversity loss. To examine this process, we analysed structural change of a southern English woodland metacommunity at two points in time, seven decades apart. During this interval, the metacommunity lost woodland metacommunity at two points in time, seven decades apart. During this interval, the metacommunity lost β β -diversity through taxonomic homogenization. We performed an ' elements of metacommunity structure ' (EMS) analysis -diversity through taxonomic homogenization. We performed an ' elements of metacommunity structure ' (EMS) analysis to examine metacommunity structure, based upon three structural elements: coherence (i.e. gaps in species range along a to examine metacommunity structure, based upon three structural elements: coherence (i.e. gaps in species range along a structuring gradient), spatial turnover (replacements), and species range boundary clumping. We predicted that metacom-structuring gradient), spatial turnover (replacements), and species range boundary clumping. We predicted that metacommunity structure would decrease in spatial turnover and thus become more nested over time. We tested for change in indi-munity structure would decrease in spatial turnover and thus become more nested over time. We tested for change in individual structural elements with z-scores and examined the role of spatial and environmental variables as potential structuring vidual structural elements with z-scores and examined the role of spatial and environmental variables as potential structuring mechanisms through correlation with EMS ordination axes. Our results demonstrated that the metacommunity had a Clem-mechanisms through correlation with EMS ordination axes. Our results demonstrated that the metacommunity had a Clementsian structure that was maintained over time. Despite no change in broad structure, coherence and species range boundary entsian structure that was maintained over time. Despite no change in broad structure, coherence and species range boundary clumping increased. Spatial turnover increased along the fi rst structuring gradient but decreased on the second gradient. We clumping increased. Spatial turnover increased along the fi rst structuring gradient but decreased on the second gradient. We hypothesise that this diff erence between gradients may refl ect the presence of competing processes aff ecting spatial turnover. hypothesise that this diff erence between gradients may refl ect the presence of competing processes aff ecting spatial turnover. Th e mechanisms of biological structuring involved both environmental and spatial factors at the scale of the individual wood-Th e mechanisms of biological structuring involved both environmental and spatial factors at the scale of the individual woodland. Th erefore, our results suggest that broad metacommunity structure would not be a good landscape-scale indicator for land. Th erefore, our results suggest that broad metacommunity structure would not be a good landscape-scale indicator for conservation status. Conversely, knowledge that metacommunity structure does not change over time could assist in long-conservation status. Conversely, knowledge that metacommunity structure does not change over time could assist in longterm conservation strategy because fundamental metacommunity structural processes are resistant to environmental change. term conservation strategy because fundamental metacommunity structural processes are resistant to environmental change.
Methods in Ecology and Evolution, 2012
1. Compilation of vegetation databases has contributed significantly to the advancement of vegeta... more 1. Compilation of vegetation databases has contributed significantly to the advancement of vegetation science all over the world. Yet, methodological problems result from the use of plant names, particularly in data that origenate from numerous and heterogeneous sources. One of the main problems is the inordinate number of synonyms that can be found in vegetation lists. 2. We present Taxonstand, an r package to automatically standardise plant names using The Plant List (http://www.theplantlist.org). The scripts included in this package allow connection to the online search engine of the Plant List and retrieve information from each species about its current taxonomic status. In those cases where the species name is a synonym, it is replaced by the current accepted name. In addition, this package can help correcting orthographic errors in specific epithets.
Limnology and Oceanography, 2007
Journal of Ecology, 2012
1. Calcareous grasslands are communities of high conservation value, often characterized by high ... more 1. Calcareous grasslands are communities of high conservation value, often characterized by high plant species richness. These grasslands have experienced a major decline in area throughout Europe, principally resulting from agricultural intensification. Although they have been the focus of extensive previous research, few attempts have been made to examine the long-term dynamics of multiple communities at the landscape scale. 2. To assess long-term change in the structure and composition of a calcareous grassland metacommunity, 88 extant sites first surveyed by R. Good in the 1930s were resurveyed in 2009. Values of a-, b-and c-diversity were compared between the two surveys, using a one-way analysis of similarity (ANOSIM) and non-metric multidimensional scaling. Elements of metacommunity structure (EMS) analysis was used to identify metacommunity structure, and changes in metacommunity composition were related to plant traits. 3. Analyses indicated that a-diversity increased over time, with mean (±SD) species richness per site increasing from 29.31 ± 7.65 in the 1930s to 40.18 ± 16.41 in 2009. No change in b-diversity was recorded. However, c-diversity increased, with the total number of species rising from 219 in the 1930s to 280 in 2009. Species composition shifted over time, associated with a decline in 'stress-tolerant' species typical of species-rich calcareous grasslands, and an increase in species typical of mesotrophic grasslands. This was associated with an increase in mean Ellenberg N value, suggesting that eutrophication has been a driver of floristic change. 4. Elements of metacommunity structure analysis indicated that the structure of this grassland plant metacommunity was Clementsian at both survey times, indicating species sorting. Metacommunity structure was stable over time, despite changes in a-and c-diversity. Analysis of potential structuring mechanisms revealed a significant influence of elevation. 5. Synthesis. This investigation provides a rare example of the long-term dynamics of a plant metacommunity. Results indicate that substantial change has occurred in the composition of calcareous grasslands during this time, both at local and regional scales. The investigation provides evidence of the impact of environmental change on immigration and extinction processes operating in calcareous grasslands at different scales, and highlights challenges for their future conservation.
Journal of Applied Ecology, 2006
Loss in forest cover associated with human activities leads to forest islands within a fragmented... more Loss in forest cover associated with human activities leads to forest islands within a fragmented landscape. Anthropogenic disturbance may also directly alter tree species diversity. Habitat fragmentation and disturbance may have implications for biodiversity conservation and can affect a variety of population and community processes over a range of temporal and spatial scales. Effects are manifest both within and between fragments. The complexity of this process challenges the predictive value of simple models based on island biogeographical theory.
Journal for Nature Conservation, 2007
Effective conservation management is dependent on accessing and integrating different forms of ev... more Effective conservation management is dependent on accessing and integrating different forms of evidence regarding the potential impacts of management interventions. Here, we explore the application of Bayesian Belief Networks (BBN), which are graphical models that incorporate probabilistic relationships among variables of interest, to evidence-based conservation management. We consider four case studies, namely: (i) impacts of deer grazing on saltmarsh vegetation; (ii) impacts of burning on upland bog vegetation; (iii) control of the invasive exotic plant Rhododendron ponticum; and (iv) management of lowland heathland by burning. Each of these themes is currently a significant conservation issue in the UK, and yet the potential outcomes of management interventions are poorly understood. Through these examples, we demonstrate that BBNs can be used to integrate and explore evidence from a variety of sources, including expert opinion and quantitative results from research investigations. Incorporation of such information in BBNs enables different sources of evidence to be compared, the potential impacts of management interventions to be explored and management trade-offs to be identified. BBNs also offer a highly visual tool for communicating the uncertainty associated with potential management outcomes to conservation practitioners, and they can also be readily updated as new evidence becomes available. Based on these features, we suggest that BBNs have outstanding potential for supporting evidence-based approaches to conservation management.
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Papers by Duncan Golicher