Biology subjects

Negret, P. J.

Publications and source records attributed to Negret, P. J..

5 recordsLinked to original sources

bioRxiv2022

Neotropical birds and mammals show divergent behaviour responses to human pressure

Human presence and habitat disturbance (together human pressure hereafter) can generate a deep fear in animals and this can influence their behaviour. Altered animal behaviour, such as shifts in diel activity patterns, affect many species and species interactions, which can induce changes in individual fitness, species-level population persistence, evolutionary dynamics, and ecosystem-level biodiversity. However, whether dial activity behavioural responses to human pressure are consistent among key functional groups has been poorly studied. For example, while medium to large mammal species tend to become more nocturnal in areas with high human pressure, its unclear if sympatric/co-occurring birds display similar or opposite patterns. This is an important knowledge gap because synchronous or opposing guild-level shifts can shape consequences for food-web dynamics (predation and competition), stability of interaction networks and ecosystem functioning. Here we used information from camera trapping along a gradient of human pressure in the Colombian Llanos region to assess diel activity changes in birds and mammals. We found that the diel activity of over 45% of the bird and 50% of the mammals assessed significantly changed where there was higher human pressures, with mammals becoming more nocturnal and birds more diurnal. The opposing behavioural responses to humans among vertebrate functional groups has significant repercussions for the fields of community ecology, including intraguild predation and competition, and may be a significant ecosystem-level conservation consideration.

ecology↗

bioRxiv2021

Language barriers in global bird conservation

Multiple languages being spoken within a species distribution can impede communication among conservation stakeholders, the compilation of scientific information, and the development of effective conservation actions. Here, we investigate the number of official languages spoken within the distributions of 10,863 bird species to identify which ones might be particularly affected by consequences of language barriers. We show that 1587 species have 10 languages or more spoken within their distributions. Threatened, migratory and wide-ranging species have especially many languages spoken within their distribution. Particularly high numbers of species with many languages within their distribution are found in Eastern Europe, Russia and central and western Asia. Global conservation efforts would benefit from implementing guidelines to overcome language barriers, especially in regions with high species and language diversity.

ecology↗

bioRxiv2021

The role of elections as drivers of tropical deforestation

Tropical forests support immense biodiversity and provide essential ecosystem services for billions of people. Despite this value, tropical deforestation continues at a high rate. Emerging evidence suggests that elections can play an important role in shaping deforestation, for instance by incentivising politicians to allow increased utilisation of tropical forests in return for political support and votes. Nevertheless, the role of elections as a driver of deforestation has not been comprehensively tested at broad geographic scales. Here, we created an annual database from 2001 to 2018 on political elections and forest loss for 55 tropical nations and modelled the effect of elections on deforestation. In total, 1.5 million km2 of forest was lost during this time period, and the rate of deforestation increased in 37 (67%) of the analysed countries. Deforestation was significantly lower in years with presidential or lower chamber elections compared to non-election years, which is in contrast to previous local-scale studies. Moreover, deforestation was significantly higher in presidential or lower chamber elections that are competitive (i.e. when the opposition can participate in elections and has a legitimate chance to gain governmental power) compared to uncompetitive elections. Our results document a pervasive loss of tropical forests and suggest that competitive elections are potential drivers of deforestation. We recommned that organisations monitoring election transparency and fairness should also monitor environmental impacts such as forest loss, habitat destruction and resource exploitation. This would benefit the tracking of potential illegal vote buying with natural resources.

ecology↗

bioRxiv2020

Deforestation and bird habitat loss in Colombia

Tropical forests harbor most of the planets terrestrial biodiversity, and their loss means destruction of habitat for many species. Tropical deforestation continues at high rates in many regions, but it is often reported only in terms of area lost or its impacts on high-profile threatened species. We estimated the impact of both past and projected future deforestation on habitat extent for the entire assemblage of forest-dependent birds across Colombia, the country with more bird species than any other. Of the 550 forest-dependent species analysed, Almost all (n=536; 96.5%) had lost habitat, and 18% had lost at least half of their habitat by 2015. We used the recently developed Loss Index (LI) to capture the severity of habitat loss for the forest bird assemblage, discovering that the current LI for Colombia is 35, which means 35% of bird species have lost at least 35% of their habitat. The national LI for Colombia is projected to rise to 43 by 2040 if recent forest loss trends continue. There were large regional differences; Caribe had an LI of 82 while for the Pacific it was 14. A threat assessment for the regionally endemic species in the country showed that 12 (30%) of the species that are projected to lose 50% or more of their historical habitat by 2040 are not currently classified as threatened by the IUCN, suggesting that there are many species that are not listed but that face an imminent extinction threat from habitat loss. This extensive habitat depletion affecting entire species assemblages has significant implications for tropical forest ecosystems, and risks eroding ecosystem function and ecosystem service provision.

ecology↗

bioRxiv2020

A data-driven geospatial workflow to improve mapping species distributions and assessing extinction risk under the IUCN Red List.

Species distribution maps are essential for assessing extinction risk and guiding conservation efforts. Here, we developed a data-driven, reproducible geospatial workflow to map species distributions and evaluate their conservation status consistent with the guidelines and criteria of the IUCN Red List. Our workflow follows five automated steps to refine the distribution of a species starting from its Extent of Occurrence (EOO) to Area of Habitat (AOH) within the species range. The ranges are produced with an Inverse Distance Weighted (IDW) interpolation procedure, using presence and absence points derived from primary biodiversity data. As a case-study, we mapped the distribution of 2,273 bird species in the Americas, 55% of all terrestrial birds found in the region. We then compared our produced species ranges to the expert-drawn IUCN/BirdLife range maps and conducted a preliminary IUCN extinction risk assessment based on criterion B (Geographic Range). We found that our workflow generated ranges with fewer errors of omission, commission, and a better overall accuracy within each species EOO. The spatial overlap between both datasets was low (28%) and the expert-drawn range maps were consistently larger due to errors of commission. Their estimated Area of Habitat (AOH) was also larger for a subset of 741 forest-dependent birds. We found that incorporating geospatial data increased the number of threatened species by 52% in comparison to the 2019 IUCN Red List. Furthermore, 103 species could be placed in threatened categories (VU, EN, CR) pending further assessment. The implementation of our geospatial workflow provides a valuable alternative to increase the transparency and reliability of species risk assessments and improve mapping species distributions for conservation planning and decision-making.

ecology↗