Browsing by Author "Tobias, Joseph A."
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- Assessing taxonomic and functional change in British breeding bird assemblages over timePublication . Wayman, Joseph P.; Sadler, Jonathan P.; Pugh, Thomas A. M.; Martin, Thomas E.; Tobias, Joseph A.; Matthews, Thomas J.AIM: The aim was to identify the primary drivers of compositional change in breeding bird assemblages over a 40-year period. LOCATION: Britain. TIME PERIOD: From 1970 to 2010. MAJOR TAXA STUDIED: Birds. METHODS: Using morphological trait measurements and a dataset of presence-absence data for British breeding birds surveyed in 10 km × 10 km hectads during two time periods, we calculated temporal taxonomic and functional beta diversity for each hectad alongside the change in species richness, mean nearest taxon distance (MNTD) and mean pairwise distance (MPD). We also estimated potential drivers of beta diversity, including climatic and land-use and land-cover (LULC) change variables, elevation and assemblage species richness in 1970 (1970rich). We used random forest regressions to test which variables best explained compositional change in the assemblages. We also assessed spatial taxonomic and functional change by analysing multiple-site beta diversity and pairwise dissimilarities between time periods. RESULTS: Initial (1970) species richness was the most important predictor (highest importance score) across all models, with areas characterized by higher initial richness experiencing less assemblage change overall. The coordinates included to capture spatial autocorrelation in the data were also important predictors of change. Most cli-mate and LULC variables had relatively low explanatory power; elevation and average temperature were the most influential. All metrics increased slightly with increasing elevation, except for species richness change and MPD, which decreased. MAIN CONCLUSIONS: The composition of British breeding bird assemblages changed substantially between 1970 and 2010. Spatial heterogeneity increased, both taxonomically and functionally. We show evidence that hectads with larger assemblages have been buffered from temporal diversity change and that those at higher elevations changed more in composition than those at lower elevations. Overall, coarse-resolution climate and LULC explained only small to moderate amounts of variation, suggesting that stochastic assembly change or finer-scale drivers might be drivers of temporal changes in assemblage composition.
- Assessing tropical forest restoration after fire using birds as indicators : An afrotropical case studyPublication . Rurangwa, Marie Laure; Matthews, Thomas J.; Niyigaba, Protais; Tobias, Joseph A.; Whittaker, Robert J.The necessity to restore rainforest habitats degraded by anthropogenic fires is widely recognized, however, research on restoration approaches has mainly centred on the recovery of forest structural complexity. There is insufficient evidence on the efficacy of restoration methods in the recovery of the faunal diversity and features linked to key ecosystem functions. We assessed the taxonomic diversity and functional trait structure of bird assemblages in undisturbed primary forest and fire-affected habitats undergoing natural regeneration, as well as areas of assisted natural regeneration, in Nyungwe National Park, Rwanda. We compiled bird occurrence data from point-count sampling, and obtained morphological traits for all species in our assemblages using measurements taken from wild birds and museum specimens. We found marked differences in species composition between primary forest habitats and regenerating forest, with similarity increasing over time since perturbation. Taxonomic diversity was higher in primary forest, and similar between the two restoration approaches. Functional diversity was lower in assisted naturally regenerated habitats, although separate analyses within dietary guilds revealed no differences across habitats. Among desired restoration outcomes, tree species diversity was the leading positive driver of avian species diversity, fern coverage exerted negative effects, while canopy cover had a positive but weak influence. Our findings underscore the importance of preventing anthropogenic fires in tropical rainforest since their impacts on ecological processes are not easily reversed, as shown by the lack of improvement in avian diversity metrics under assisted naturally regeneration in relation to natural regeneration. We stress the need to document both floral and faunal recovery in order to aid informed decision-making on restoration methods.
- AVONET : morphological, ecological and geographical data for all birdsPublication . Tobias, Joseph A.; Sheard, Catherine; Pigot, Alex L.; Devenish, Adam J. M.; Yang, Jingyi; Sayol, Ferran; Neate‐Clegg, Montague H. C.; Alioravainen, Nico; Weeks, Thomas L.; Barber, Robert A.; Walkden, Patrick A.; Cooper, Jacob C.; Pauwels, Olivier S. G.; Analuddin, Kangkuso; Fjeldså, Jon; Seddon, Nathalie; Sweet, Paul R.; DeClerck, Fabrice A. J.; Naka, Luciano N.; Brawn, Jeffrey D.; Aleixo, Alexandre; MacGregor, Hannah E. A.; Böhning‐Gaese, Katrin; Rahbek, Carsten; Fritz, Susanne A.; Thomas, Gavin H.; Schleuning, Matthias; Jones, Samuel E. I.; Vincent, Claire; Phillips, Anna G.; Marples, Nicola M.; Montaño‐Centellas, Flavia A.; Leandro‐Silva, Victor; Claramunt, Santiago; Darski, Bianca; Freeman, Benjamin G.; Bregman, Tom P.; Cooney, Christopher R.; Hughes, Emma C.; Capp, Elliot J. R.; Varley, Zoë K.; Friedman, Nicholas R.; Korntheuer, Heiko; Corrales‐Vargas, Andrea; Trisos, Christopher H.; Weeks, Brian C.; Hanz, Dagmar M.; Töpfer, Till; Bravo, Gustavo A.; Remeš, Vladimír; Nowak, Larissa; Carneiro, Lincoln S.; Moncada R., Amilkar J.; Matysioková, Beata; Baldassarre, Daniel T.; Martínez‐Salinas, Alejandra; Wolfe, Jared D.; Chapman, Philip M.; Daly, Benjamin G.; Sorensen, Marjorie C.; Neu, Alexander; Ford, Michael A.; Mayhew, Rebekah J.; Fabio Silveira, Luis; Kelly, David J.; Annorbah, Nathaniel N. D.; Pollock, Henry S.; Grabowska‐Zhang, Ada M.; McEntee, Jay P.; Carlos T. Gonzalez, Juan; Meneses, Camila G.; Muñoz, Marcia C.; Powell, Luke L.; Jamie, Gabriel A.; Matthews, Thomas J.; Johnson, Oscar; Brito, Guilherme R. R.; Zyskowski, Kristof; Crates, Ross; Harvey, Michael G.; Jurado Zevallos, Maura; Hosner, Peter A.; Bradfer‐Lawrence, Tom; Maley, James M.; Stiles, F. Gary; Lima, Hevana S.; Provost, Kaiya L.; Chibesa, Moses; Mashao, Mmatjie; Howard, Jeffrey T.; Mlamba, Edson; Chua, Marcus A. H.; Li, Bicheng; Gómez, M. Isabel; García, Natalia C.; Päckert, Martin; Fuchs, Jérôme; Ali, Jarome R.; Derryberry, Elizabeth P.; Carlson, Monica L.; Urriza, Rolly C.; Brzeski, Kristin E.; Prawiradilaga, Dewi M.; Rayner, Matt J.; Miller, Eliot T.; Bowie, Rauri C. K.; Lafontaine, René‐Marie; Scofield, R. Paul; Lou, Yingqiang; Somarathna, Lankani; Lepage, Denis; Illif, Marshall; Neuschulz, Eike Lena; Templin, Mathias; Dehling, D. MatthiasFunctional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.
- AVOTREX: A Global Dataset of Extinct Birds and Their TraitsPublication . Sayol, Ferran; Wayman, Joseph P.; Dufour, Paul; Martin, Thomas E.; Hume, Julian P.; Jørgensen, Maria Wagner; Martínez‐Rubio, Natàlia; Sanglas, Ariadna; Soares, Filipa C.; Cooke, Rob; Mendenhall, Chase D.; Margolis, Jay R.; Illera, Juan Carlos; Lemoine, Rhys; Benavides, Eva; Lapiedra, Oriol; Triantis, Kostas A.; Pigot, Alex L.; Tobias, Joseph A.; Faurby, Søren; Matthews, Thomas J.Motivation Human activities have been reshaping the natural world for tens of thousands of years, leading to the extinction of hundreds of bird species. Past research has provided evidence of extinction selectivity towards certain groups of species, but trait information is lacking for the majority of clades, especially for prehistoric extinctions identified only through subfossil remains. This incomplete knowledge potentially obscures the structure of natural communities, undermining our ability to infer changes in biodiversity across space and time, including trends in functional and phylogenetic diversity. Biases in currently available trait data also limit our ability to identify drivers and processes of extinction. Here we present AVOTREX, an open-access database of species traits for all birds known to have gone extinct in the last 130,000 years. This database provides detailed morphological information for 610 extinct species, along with a pipeline to build phylogenetic trees that include these extinct species. Main Types of Variables Contained For each extinct bird species, we provide information on the taxonomy, geographic location, and period of extinction. We also present data on island endemicity, flight ability, and body mass, as well as standard measurements of external (matching the AVONET database of extant birds) and skeletal morphology from museum specimens where available. To ensure comprehensive morphological data coverage, we estimate all missing morphological measurements using a data imputation technique based on machine learning. Finally, we provide an R package to graft all extinct species onto a global phylogeny of extant species (BirdTree).
- Effects of land‐use change on avian taxonomic, functional and phylogenetic diversity in a tropical montane rainforestPublication . Rurangwa, Marie Laure; Aguirre‐Gutiérrez, Jesús; Matthews, Thomas J.; Niyigaba, Protais; Wayman, Joseph P.; Tobias, Joseph A.; Whittaker, Robert J.AIM: Although land use change is a leading cause of biodiversity loss worldwide, there is scant information on the extent to which it has affected the structure and composition of bird communities in the Afrotropical region. This study aimed to quantify the effects of habitat transformation on taxonomic, functional and phylogenetic diversity in Afrotropical bird communities. LOCATION: Nyungwe landscape, a montane rainforest with adjoining farmland in south-west Rwanda. METHODS: Data on bird occurrence, abundance and functional traits were collected in 2017/18 using point counts. We also collected data on habitat and morphological traits for all bird species recorded. We quantified bird diversity using a range of metrics, including the inverse Simpson index, functional dispersion and the standardized effect size of mean nearest taxon distance. RESULTS: In comparison with primary forest areas, even low levels of land use change altered species composition and reduced species diversity. Although overall functional diversity and phylogenetic diversity were similar across land use types, we found a significant contraction of trophic and locomotory trait structures of bird communities in restored areas and cultivated areas, respectively. Soil moisture, elevation and lower vegetation height were major factors influencing taxonomic, functional and phylogenetic dimensions of bird communities, although their effects varied across these dimensions. MAIN CONCLUSIONS: The sensitivity of forest species to minor habitat disturbance emphasizes the value of conserving primary vegetation. Long-term conservation of bird communities in Afromontane ecosystems requires halting wide-scale destruction of primary forest, promoting vegetation heterogeneity in the ecological restoration of degraded habitats and adopting wildlife-friendly agricultural practices. Our results suggest that monitoring and conservation in these landscapes can be refined using taxonomic, functional and phylogenetic diversity metrics to provide complementary information about the current and likely future impacts of land use change.
- Identifying the Drivers of Spatial Taxonomic and Functional Beta-Diversity of British Breeding BirdsPublication . Wayman, Joseph P.; Sadler, Jonathan P.; Pugh, Thomas A. M.; Martin, Thomas E.; Tobias, Joseph A.; Matthews, Thomas J.Spatial variation in community composition may be driven by a variety of processes, including environmental filtering and dispersal limitation. While work has been conducted on the relative importance of these processes on various taxa and at varying resolutions, tests using high-resolution empirical data across large spatial extents are sparse. Here, we use a dataset on the presence/absence of breeding bird species collected at the 10 km × 10 km scale across the whole of Britain. Pairwise spatial taxonomic and functional beta diversity, and the constituent components of each (turnover and nestedness/richness loss or gain), were calculated alongside two other measures of functional change (mean nearest taxon distance and mean pairwise distance). Predictor variables included climate and land use measures, as well as a measure of elevation, human influence, and habitat diversity. Generalized dissimilarity modeling was used to analyze the contribution of each predictor variable to variation in the different beta diversity metrics. Overall, we found that there was a moderate and unique proportion of the variance explained by geographical distance per se, which could highlight the role of dispersal limitation in community dissimilarity. Climate, land use, and human influence all also contributed to the observed patterns, but a large proportion of the explained variance in beta diversity was shared between these variables and geographical distance. However, both taxonomic nestedness and functional nestedness were uniquely predicted by a combination of land use, human influence, elevation, and climate variables, indicating a key role for environmental filtering. These findings may have important conservation implications in the face of a warming climate and future land use change.
- Threatened and extinct island endemic birds of the world: Distribution, threats and functional diversityPublication . Matthews, Thomas J.; Wayman, Joseph P.; Cardoso, Pedro; Sayol, Ferran; Hume, Julian P.; Ulrich, Werner; Tobias, Joseph A.; Soares, Filipa C.; Thébaud, Christophe; Martin, Thomas E.; Triantis, Kostas A.AIM: The world's islands support disproportionate levels of endemic avian biodiversity despite suffering numerous extinctions. While intensive recent research has focused on island bird conservation or extinction, few global syntheses have considered these factors together from the perspective of morphological trait diversity. Here, we provide a global summary of the status and ecology of extant and extinct island birds, the threats they face and the implications of species loss for island functional diversity. LOCATION: Global. TAXON: Birds. METHODS: We provide a review of the literature on threatened and extinct island birds, with a particular focus on global studies that have incorporated functional diversity. Alongside this, we analyse IUCN Red List data in relation to distribution, threats and taxonomy. Using null models and functional hypervolumes, in combination with morphological trait data, we assess the functional diversity represented by threatened and extinct island endemic birds. RESULTS AND MAIN CONCLUSIONS: We find that almost half of all island endemic birds extant in 1500 CE are currently either extinct or threatened with extinction, with the majority of threatened extant species having declining population trends. We also found evidence of 66 island endemic subspecies extinctions. The primary threats to extant island endemic birds currently are agriculture, biological resource use, and invasive species. While there is overlap between the hotspots of threatened and extinct island endemics birds, there are some notable differences, including the Philippines and Indonesia, which support a substantial number of threatened species but have no recorded post-1500 CE bird extinctions. Traits associated with threatened island endemic birds are large body mass, flightlessness, aquatic predator, omnivorous and vertivorous trophic niches, marine habitat affinity, and, paradoxically, higher dispersal ability. Critically, we find that threatened endemics (i) occupy distinct areas of beak morphospace, and (ii) represent substantial unique areas of the overall functional space of island endemics. We caution that the loss of threatened species may have severe effects on the ecological functions birds provide on islands.