Biology subjects

Hatfield, J. H.

Publications and source records attributed to Hatfield, J. H..

3 recordsLinked to original sources

bioRxiv2025

Development of the invertebrate faunas of anthropogenic habitats

AimWe aimed to determine the relationships between species association with humans, their levels of habitat specialisation, and the extent to which their geographic ranges have increased or decreased. LocationGreat Britain. Time periodPresent (1981-2020) Major taxa studiedTerrestrial invertebrates (n=1,722 species). MethodsWe determined the habitat associations for each of 1,722 species from 14 taxonomic groups in each of 18 land cover types in Great Britain. We used these values to calculate a human association index (based on whether species occupy human-modified land cover types, such as urban, suburban and coniferous plantation habitats, or occur in relatively unmodified land covers, such as several coastal habitats and marshlands) and habitat specialisation index (whether they are restricted to a few land cover types, or widely distributed across different land cover types) for each species. We then investigated the relationship between human association and habitat specialisation, as well as the relationship between human association and two metrics of range change between 1981-2000 and 2001-2020. ResultsContrary to previous hypotheses, we find no evidence that species associated with human-modified environments are more likely to be habitat generalists. Furthermore, human-associated species were more likely to increase. On average, the geographic distributions of the most human-associated third of species increased by 58% over the study period, whereas the least human associated third of species declined by 7.1%. Main conclusionsHumans have had increasingly large impacts on the worlds ecosystems, generating an intensity gradient of human-modification, including novel (anthropogenic) environments. Our findings show that new environments have provided opportunities for species to colonise, generating faunas which include species that have become human-associated specialists. The ongoing expansions of species in ecosystems with relatively high levels of human modification are key components of the future of biodiversity in the Anthropocene.

ecology↗

bioRxiv2023

Globally abundant birds disproportionately inhabit anthropogenic environments

Research into biodiversity change predominantly focuses on rarity and declines, but many ecological processes are governed by abundant species. Analysing 3,146 terrestrial bird species across 5,454 field-sampled sites, we find that three times more species in the top quartile for global abundance are more likely to occur in ecosystems characterised by major human land-cover modification (croplands, plantation forest, urban areas and pasture), compared with species in the bottom quartile. The likelihood of inhabiting human-modified environments consistently increases with global abundance across species with different dietary requirements, whereas low abundance species tend to have increased probabilities of occurrence (within their ranges) in relatively unmodified environments. Our findings suggest that human modification of the Earths land surface has favoured anthrophilic species able to thrive in widespread anthromes. One-Sentence SummaryThe worlds most abundant birds disproportionately inhabit croplands, plantation forests, urban areas and pastures.

ecology↗

bioRxiv2023

Constraints on avian seed dispersal reduce potential for resilience in degraded tropical forests

1. Seed dispersal - one of the many services supplied by biodiversity - is a critical process underpinning the resilience of tropical forests. Forest loss or degradation typically leads to defaunation, altering seed transfer dynamics and impairing the ability of forested habitats to regenerate or recover from perturbation. However, the extent of defaunation, and its likely impacts on the seed dispersers needed to restore highly degraded or clear-felled areas, remains poorly understood, particularly in human-modified tropical forest landscapes. 2. To quantify defaunation of seed-dispersing birds, we used field survey data from more than 400 transects in three regions of Brazil, first comparing the recorded assemblages with those predicted by geographic range maps, and then assessing frugivore habitat associations across gradients of land cover modification at local scales. 3. We found that current bird assemblages have lower functional trait diversity than predicted by species range maps in Amazonia (4-6%), with a greater reduction (28%) for the Atlantic Forest region, which has been more heavily deforested for a longer period. These reductions are probably caused by local extinctions of forest-dependent bird species following land-use change. 4. Direct measures of seed dispersal are difficult to obtain, so we instead focused on the potential for seed transfer inferred from shared species occurrence between land cover types. Of 83 predominantly frugivorous bird species recorded in relatively intact forests, we show that 10% were absent from degraded forest, and 57% absent from the surrounding matrix of agricultural land covers, including many of the large-beaked species. Of 112 frugivorous species using degraded forest, 47% were absent from matrix habitats. 5. Our findings suggest that degraded forest can supply seed dispersal services to adjacent cleared lands, and that direct transfer of seeds from intact forest to cleared areas may be limited, particularly for large-seeded trees. We conclude that resilience of tropical forest landscapes is best achieved by protecting a mosaic of forest types, including sufficient core areas of intact forest surrounded by buffer zones of degraded forest.

ecology↗