Sandra Tranquilli | Aarhus University (original) (raw)

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Papers by Sandra Tranquilli

Research paper thumbnail of Recent decline in suitable environmental conditions for African great apes Diversity and Distributions

Aim To predict the distribution of suitable environmental conditions (SEC) for eight African grea... more Aim To predict the distribution of suitable environmental conditions (SEC) for eight African great ape taxa for a first time period, the 1990s and then project it to a second time period, the 2000s; to assess the relative importance of factors influencing SEC distribution and to estimate rates of SEC loss, isolation and fragmentation over the last two decades. Location Twenty-two African great ape range countries. Methods We extracted 15,051 presence localities collected between 1995 and 2010 from 68 different areas surveyed across the African ape range. We combined a maximum entropy algorithm and logistic regression to relate ape presence information to environmental and human impact variables from the 1990s with a resolution of 5 9 5 km across the entire ape range. We then made SEC projections for the 2000s using updated human impact variables. Results Total SEC area was approximately 2,015,480 and 1,807,653 km 2 in the 1990s and 2000s, respectively. Loss of predicted SEC appeared highest for Cross River gorillas (À59%), followed by eastern gorillas (À52%), western gorillas (À32%), bonobos (À29%), central chimpanzees (À17%) and western chimpanzees (À11%). SEC for Nigeria-Cameroon chimpanzees and eastern chimpanzees was not greatly reduced. Except for Cross River and eastern gorillas, the number of SEC patches did not change significantly, suggesting that SEC loss was caused mainly by patch size reduction. Main conclusions The first continent-wide perspective of African ape SEC distribution shows dramatic declines in recent years. The model has clear limitations for use at small geographic scales, given the quality of available data and the coarse resolution of predictions. However, at the large scale it has potential for informing international policymaking, mitigation of resource extraction and infrastructure development, as well as for spatial prioritization of conservation effort and evaluating conservation effectiveness.

Research paper thumbnail of Table S1 protected areas in tropical Africa

Research paper thumbnail of HicksEtAlBiliTransects2014SupplMtWiFigs

Research paper thumbnail of Supplementary Text

Research paper thumbnail of Drivers of extinction risk in African mammals: the interplay of distribution state, human pressure, conservation response and species biology

Philosophical Transactions of the Royal Society B: Biological Sciences, 2014

Research paper thumbnail of Lack of conservation effort rapidly increases African great ape extinction risk

A network of resource management areas (RMAs) exists across tropical Africa to protect natural re... more A network of resource management areas (RMAs) exists across tropical Africa to protect natural resources. However, many are poorly managed and weakly protected. We evaluated how the lack of conservation effort influences the extinction risk of African great apes. We compiled information on presence/absence of primary (law enforcement guards) and secondary (tourism, research) conservation activities and non governmental conservation organizations (NGOs) support for 109 RMAs over the last 20 years. Along with these data, we collected environmental and anthropogenic variables, including recent records of ape presence/absence for all RMAs. As expected, law enforcement as a primary activity was the best predictor of ape survival rather than tourism or research as secondary activities. Furthermore, long-term NGO support had a significant positive influence on ape persistence. Our study demonstrates the feasibility of evaluating the relative importance of different conservation activities, an important step towards more evidence-based approaches in ape conservation.

Research paper thumbnail of Canadian Living Planet Report

Research paper thumbnail of Lack of conservation rapidly increases African great ape extinction risk_Supplementary Material

Research paper thumbnail of The alarm call system of two species of black-and-white colobus monkeys (Colobus polykomos and Colobus guereza)

Journal of Comparative Psychology, 2009

Research paper thumbnail of Status Survey and Conservation Action Plan for the Eastern Chimpanzee (Pan troglodytes schweinfurthii) 2010-2020

Research paper thumbnail of Tranquilli et al.2012 Supplementar Material

Research paper thumbnail of Panthropology of the Fourth Chimpanzee: A Contribution to Cultural Primatology

Primates of Gashaka, 2010

... A classic study has compiled the behavioural patterns at 9 long-term chimpan-zee research sit... more ... A classic study has compiled the behavioural patterns at 9 long-term chimpan-zee research sites. ... Our contribution attempts to at least partly fill in the noticeable gap in chimpan-zee research with respect to the “fourth chimpanzee” – the subspecies vellerosus. ...

Research paper thumbnail of Absence of evidence is not evidence of absence: Discovery of a large, continuous population of Pan troglodytes schweinfurthii in the Central Uele region of northern DRC

Biological Conservation, 2014

Research paper thumbnail of Protected areas in tropical Africa: Assessing threats and conservation activities

by Thomas Breuer, Alasdair R Harris, Stephen Blake, Charles-Albert Petre, Sandra Tranquilli, Fidèle Amsini, Tim Davenport, Colin A Chapman, Takeshi Furuichi, Kouame Paul Ngoran, Sebastien Regnaut, Cletus Balangtaa, Manasseh Eno-Nku, and Rebecca Chancellor

PLoS ONE

Numerous protected areas (PAs) have been created in Africa to safeguard wildlife and other natura... more Numerous protected areas (PAs) have been created in Africa to safeguard wildlife and other natural resources. However, significant threats from anthropogenic activities and decline of wildlife populations persist, while conservation efforts in most PAs are still minimal. We assessed the impact level of the most common threats to wildlife within PAs in tropical Africa and the relationship of conservation activities with threat impact level. We collated data on 98 PAs with tropical forest cover from 15 countries across West, Central and East Africa. For this, we assembled information about local threats as well as conservation activities from published and unpublished literature, and questionnaires sent to long-term field workers. We constructed general linear models to test the significance of specific conservation activities in relation to the threat impact level. Subsistence and commercial hunting were identified as the most common direct threats to wildlife and found to be most pr...

Research paper thumbnail of Recent decline in suitable environmental conditions for African great apes Diversity and Distributions

Aim To predict the distribution of suitable environmental conditions (SEC) for eight African grea... more Aim To predict the distribution of suitable environmental conditions (SEC) for eight African great ape taxa for a first time period, the 1990s and then project it to a second time period, the 2000s; to assess the relative importance of factors influencing SEC distribution and to estimate rates of SEC loss, isolation and fragmentation over the last two decades. Location Twenty-two African great ape range countries. Methods We extracted 15,051 presence localities collected between 1995 and 2010 from 68 different areas surveyed across the African ape range. We combined a maximum entropy algorithm and logistic regression to relate ape presence information to environmental and human impact variables from the 1990s with a resolution of 5 9 5 km across the entire ape range. We then made SEC projections for the 2000s using updated human impact variables. Results Total SEC area was approximately 2,015,480 and 1,807,653 km 2 in the 1990s and 2000s, respectively. Loss of predicted SEC appeared highest for Cross River gorillas (À59%), followed by eastern gorillas (À52%), western gorillas (À32%), bonobos (À29%), central chimpanzees (À17%) and western chimpanzees (À11%). SEC for Nigeria-Cameroon chimpanzees and eastern chimpanzees was not greatly reduced. Except for Cross River and eastern gorillas, the number of SEC patches did not change significantly, suggesting that SEC loss was caused mainly by patch size reduction. Main conclusions The first continent-wide perspective of African ape SEC distribution shows dramatic declines in recent years. The model has clear limitations for use at small geographic scales, given the quality of available data and the coarse resolution of predictions. However, at the large scale it has potential for informing international policymaking, mitigation of resource extraction and infrastructure development, as well as for spatial prioritization of conservation effort and evaluating conservation effectiveness.

Research paper thumbnail of Table S1 protected areas in tropical Africa

Research paper thumbnail of HicksEtAlBiliTransects2014SupplMtWiFigs

Research paper thumbnail of Supplementary Text

Research paper thumbnail of Drivers of extinction risk in African mammals: the interplay of distribution state, human pressure, conservation response and species biology

Philosophical Transactions of the Royal Society B: Biological Sciences, 2014

Research paper thumbnail of Lack of conservation effort rapidly increases African great ape extinction risk

A network of resource management areas (RMAs) exists across tropical Africa to protect natural re... more A network of resource management areas (RMAs) exists across tropical Africa to protect natural resources. However, many are poorly managed and weakly protected. We evaluated how the lack of conservation effort influences the extinction risk of African great apes. We compiled information on presence/absence of primary (law enforcement guards) and secondary (tourism, research) conservation activities and non governmental conservation organizations (NGOs) support for 109 RMAs over the last 20 years. Along with these data, we collected environmental and anthropogenic variables, including recent records of ape presence/absence for all RMAs. As expected, law enforcement as a primary activity was the best predictor of ape survival rather than tourism or research as secondary activities. Furthermore, long-term NGO support had a significant positive influence on ape persistence. Our study demonstrates the feasibility of evaluating the relative importance of different conservation activities, an important step towards more evidence-based approaches in ape conservation.

Research paper thumbnail of Canadian Living Planet Report

Research paper thumbnail of Lack of conservation rapidly increases African great ape extinction risk_Supplementary Material

Research paper thumbnail of The alarm call system of two species of black-and-white colobus monkeys (Colobus polykomos and Colobus guereza)

Journal of Comparative Psychology, 2009

Research paper thumbnail of Status Survey and Conservation Action Plan for the Eastern Chimpanzee (Pan troglodytes schweinfurthii) 2010-2020

Research paper thumbnail of Tranquilli et al.2012 Supplementar Material

Research paper thumbnail of Panthropology of the Fourth Chimpanzee: A Contribution to Cultural Primatology

Primates of Gashaka, 2010

... A classic study has compiled the behavioural patterns at 9 long-term chimpan-zee research sit... more ... A classic study has compiled the behavioural patterns at 9 long-term chimpan-zee research sites. ... Our contribution attempts to at least partly fill in the noticeable gap in chimpan-zee research with respect to the “fourth chimpanzee” – the subspecies vellerosus. ...

Research paper thumbnail of Absence of evidence is not evidence of absence: Discovery of a large, continuous population of Pan troglodytes schweinfurthii in the Central Uele region of northern DRC

Biological Conservation, 2014

Research paper thumbnail of Protected areas in tropical Africa: Assessing threats and conservation activities

by Thomas Breuer, Alasdair R Harris, Stephen Blake, Charles-Albert Petre, Sandra Tranquilli, Fidèle Amsini, Tim Davenport, Colin A Chapman, Takeshi Furuichi, Kouame Paul Ngoran, Sebastien Regnaut, Cletus Balangtaa, Manasseh Eno-Nku, and Rebecca Chancellor

PLoS ONE

Numerous protected areas (PAs) have been created in Africa to safeguard wildlife and other natura... more Numerous protected areas (PAs) have been created in Africa to safeguard wildlife and other natural resources. However, significant threats from anthropogenic activities and decline of wildlife populations persist, while conservation efforts in most PAs are still minimal. We assessed the impact level of the most common threats to wildlife within PAs in tropical Africa and the relationship of conservation activities with threat impact level. We collated data on 98 PAs with tropical forest cover from 15 countries across West, Central and East Africa. For this, we assembled information about local threats as well as conservation activities from published and unpublished literature, and questionnaires sent to long-term field workers. We constructed general linear models to test the significance of specific conservation activities in relation to the threat impact level. Subsistence and commercial hunting were identified as the most common direct threats to wildlife and found to be most pr...