Drew Cronin | Wildlife Conservation Society (original) (raw)

Papers by Drew Cronin

International Journal of Comparative Psychology, 2014

Conservation Technology

Wildlife species worldwide are under threat from a range of anthropogenic threats, with declines ... more Wildlife species worldwide are under threat from a range of anthropogenic threats, with declines primarily caused by overexploitation and habitat loss associated with an increasing human population and per capita resource use. Exploitation is driven by numerous factors, but is often the result of illegal activities, such as hunting, logging, and wildlife trade. Protected areas, designed to safeguard threatened species and their habitats, are the foundation of biodiversity conservation, and several analyses have demonstrated that effective protected areas are critical to the maintenance of biodiversity. However, other analyses show that most protected areas suffer from a lack of resources and poor management. Numerous technologies have been developed to address these challenges by facilitating adaptive management via ranger-based data collection, data analysis and visualization, and strategic planning. This chapter reviews the Spatial Monitoring and Reporting Tool (SMART) platform, w...

Arctic, Antarctic, and Alpine Research, 2014

Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in t... more Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in the center of the Gulf of Guinea Pleistocene refugium. The associated forests and highlands along the southern Nigerian-Cameroon border and on the island of Bioko, known as the Biafran forests and highlands, are important formations of the Cameroon Volcanic Line owing to their wide elevational range, and on Mount Cameroon, a continuous gradient of unbroken vegetation from sea level to over 4000 m. The montane zones in the region begin 800 m above sea level forming the critically endangered Mount Cameroon and Bioko Montane Forests ecoregion.

Bioko Island, Equatorial Guinea is among the important places in Africa for the conservation of p... more Bioko Island, Equatorial Guinea is among the important places in Africa for the conservation of primates, but a cultural preference for bushmeat and a lack of effective law enforcement has encouraged commercial bushmeat hunting, threatening the survival of the remaining primate population. For over 13 years, we collected bushmeat market data in the Malabo market, recording over 35,000 primate carcasses, documenting " mardi gras " consumption patterns, seasonal carcass availability, and negative effects resulting from government intervention. We also conducted forest surveys throughout Bioko's two protected areas in order to localize and quantify primate populations and hunting pressure. Using these data, we were able to document the significant negative impact bushmeat hunting had on monkey populations, estimate which species are most vulnerable to hunting, and develop ecological niche models to approximate the distribution of each of Bioko's diurnal primate species. These results also have allowed for the identification of primate hotspots, such as the critically important southwest region of the Gran Caldera Scientific Reserve, and thus, priority areas for conservation on Bioko, leading to more comprehensive conservation recommendations. Current and future efforts now focus on bridging the gap between investigators and legislators in order to develop and effectively implement a management plan for Bioko's Gran Caldera Scientific Reserve and to develop a targeted educational campaign to reduce demand by changing consumer attitudes toward bushmeat. Using this multidisciplinary approach, informed by biological, socioeconomic, and cultural research, there may yet be a positive future for the primates of Bioko.

PeerJ, 2016

The "scaly-tailed squirrels" of the rodent family Anomaluridae have a long evol... more The "scaly-tailed squirrels" of the rodent family Anomaluridae have a long evolutionary history in Africa, and are now represented by two gliding genera (Anomalurus and Idiurus) and a rare and obscure genus (Zenkerella) that has never been observed alive by mammalogists. Zenkerella shows no anatomical adaptations for gliding, but has traditionally been grouped with the glider Idiurus on the basis of craniodental similarities, implying that either the Zenkerella lineage lost its gliding adaptations, or that Anomalurus and Idiurus evolved theirs independently. Here we present the first nuclear and mitochondrial DNA sequences of Zenkerella, based on recently recovered whole-body specimens from Bioko Island (Equatorial Guinea), which show unambiguously that Zenkerella is the sister taxon of Anomalurus and Idiurus. These data indicate that gliding likely evolved only once within Anomaluridae, and that there were no subsequent evolutionary reversals. We combine this new molecular evidence with morphological data from living and extinct anomaluromorph rodents and estimate that the lineage leading to Zenkerella has been evolving independently in Africa since the early Eocene, approximately 49 million years ago. Recently discovered fossils further attest to the antiquity of the lineage leading to Zenkerella, which can now be recognized as a classic example of a "living fossil," about which we know remarkably little. The osteological markers of gliding are estimated to have evolved along the stem lineage of the Anomalurus-Idiurus clade by the early Oligocene, potentially indicating that this adaptation evolved in response to climatic perturbations at the Eocene-Oligocene boundary (∼34 million years ago).

Bushmeat hunting is among the principal threats to larger-bodied vertebrate species, such as prim... more Bushmeat hunting is among the principal threats to larger-bodied vertebrate species, such as primates, in central Africa. However, species vary in their response to differing levels of hunting intensity, making it difficult to not only quantify the effect hunting has on wild populations, but also to plan for effective conservation interventions. In order to investigate the impact of hunting on primates on Bioko Island, Equatorial Guinea, we collected data on primate abundance and hunting intensity across three areas in the Gran Caldera Scientific Reserve (GCSR) via reconnaissance surveys. We assessed how the relative abundance and proportional representation of Bioko's seven diurnal primate species varied among the different sites and in relation to hunting intensity. Overall primate species richness and abundance were highest in areas where gun hunting was minimal, but both measures declined with increasing evidence of gun hunting. Two species of primates, Cercopithecus erythrotis and Cercopithecus nictitans, were relatively tolerant of heavy hunting, but all other species were considered vulnerable. Procolobus pennantii, a species endemic to Bioko, exhibited the highest vulnerability, and its range appears restricted to a very limited area in the southwest of the GCSR. Our analyses indicate that hunting on Bioko is a strong contributor to current patterns of primate abundance and diversity, and suggest that hunting may be driving Bioko's most threatened primates (e.g., P. pennantii) towards extinction. These results highlight the need for rapid intervention on Bioko in order to safeguard the future of its unique primates.

The ''scaly-tailed squirrels'' of the rodent family Anomaluridae have a long evolutionary history... more The ''scaly-tailed squirrels'' of the rodent family Anomaluridae have a long evolutionary history in Africa, and are now represented by two gliding genera (Anomalurus and Idiurus) and a rare and obscure genus (Zenkerella) that has never been observed alive by mammalogists. Zenkerella shows no anatomical adaptations for gliding, but has traditionally been grouped with the glider Idiurus on the basis of craniodental similarities, implying that either the Zenkerella lineage lost its gliding adaptations, or that Anomalurus and Idiurus evolved theirs independently. Here we present the first nuclear and mitochondrial DNA sequences of Zenkerella, based on recently recovered whole-body specimens from Bioko Island (Equatorial Guinea), which show unambiguously that Zenkerella is the sister taxon of Anomalurus and Idiurus. These data indicate that gliding likely evolved only once within Anomaluridae, and that there were no subsequent evolutionary reversals. We combine this new molecular evidence with morphological data from living and extinct anomaluromorph rodents and estimate that the lineage leading to Zenkerella has been evolving independently in Africa since the early Eocene, approximately 49 million years ago. Recently discovered fossils further attest to the antiquity of the lineage leading to Zenkerella, which can now be recognized as a classic example of a ''living fossil,'' about which we know remarkably little. The osteological markers of gliding are estimated to have evolved along the stem lineage of the Anomalurus–Idiurus clade by the early Oligocene, potentially indicating that this adaptation evolved in response to climatic perturbations at the Eocene–Oligocene boundary (∼34 million years ago).

Several standard reference works report the presence of Two-spotted Palm Civet Nandinia binotata ... more Several standard reference works report the presence of Two-spotted Palm Civet Nandinia binotata on Bioko Island, Equatorial Guinea. However, numerous field and bushmeat market surveys over the past 30 years have failed to record this species, hence raising concerns that it is either extremely rare or extirpated. This article reviews evidence for presence of N. binotata on Bioko and simultaneously remarks on the occurrence of four other small carnivores on this island. There is strong evidence that N. binotata, King Genet Genetta poensis, Large-spotted Genet Genetta maculata (sensu lato), and an otter (initially described as Lutra poensis) never occurred on Bioko. Central African Oyan Poiana richardsonii is the only mammalian carnivore (small or large) unequivocally recorded for Bioko. Anecdotal observations suggest that a second, unidentified, species of small carnivore may occur. Future field workers on Bioko are encouraged to obtain photographs of small carnivores, and to collect, preserve, and make known, any dead small carnivores they encounter.

DESCRIPTION A Report to the Government of Equatorial Guinea by the Bioko Biodiversity Protection ... more DESCRIPTION A Report to the Government of Equatorial Guinea by the Bioko Biodiversity Protection Program, Drexel University, Philadelphia, Pennsylvania.

Bushmeat hunting is extensive in west and central Africa as both a means for subsistence and for ... more Bushmeat hunting is extensive in west and central Africa as both a means for subsistence and for commercial gain. Commercial hunting represents one of the primary threats to wildlife in the region, and confounding factors have made it challenging to examine how external factors influence the commercial bushmeat trade. Bioko Island, Equatorial Guinea is a small island with large tracts of intact forest that support sizeable populations of commercially valuable vertebrates, especially endemic primates. The island also has a low human
population and has experienced dramatic economic growth and rapid development since the mid-1990’s. From October 1997 – September 2010, we monitored the largest bushmeat
market on Bioko in Malabo, recording over 197,000 carcasses for sale. We used these data to analyze the dynamics of the market in relation to political events, environmental legislation,
and rapid economic growth. Our findings suggest that bushmeat hunting and availability increased in parallel with the growth of Equatorial Guinea’s GDP and disposable income
of its citizens. During this 13-year study, the predominant mode of capture shifted from trapping to shotguns. Consequently, carcass volume and rates of taxa typically captured with
shotguns increased significantly, most notably including intensified hunting of Bioko's unique and endangered monkey fauna. Attempts to limit bushmeat sales, including a 2007
ban on primate hunting and trade, were only transiently effective. The hunting ban was not enforced, and was quickly followed by a marked increase in bushmeat hunting compared to hunting rates prior to the ban. Our results emphasize the negative impact that rapid development and unenforced legislation have had on Bioko’s wildlife, and demonstrate the need for strong governmental support if conservation strategies are to be successful at preventing extinctions of tropical wildlife.

Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in t... more Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in the center of the Gulf of Guinea Pleistocene refugium. The associated forests and highlands along the southern Nigerian-Cameroon border and on the island of Bioko, known as the Biafran forests and highlands, are important formations of the Cameroon
Volcanic Line owing to their wide elevational range, and on Mount Cameroon, a continuous gradient of unbroken vegetation from sea level to over 4000 m. The montane zones
in the region begin 800 m above sea level forming the critically endangered Mount Cameroon and Bioko Montane Forests ecoregion.

The broad elevational gradient of the region has resulted in high habitat diversity, leading the region to be a center for species endemism and richness across many taxa. Some of
the densest human populations in Africa also occur in this region, putting intense pressure on the forests and highlands mostly due to overexploitation and habitat loss. The governments of Nigeria, Cameroon, and Equatorial Guinea have designated protected areas in the region, but coverage is inadequate, especially for the rare montane ecosystems and endemic taxa. More importantly, protected areas are often not accompanied by effective management and regulatory enforcement. We recommend improved law enforcement and an expansion of the protected area network, as well as stronger commitments of institutional, financial, and technical support from governments and non-governmental organizations, in order to move conservation in the region in a positive direction. Without significant and immediate conservation progress, increasing anthropogenic pressure and systemic ineffectiveness of protected area management represent major concerns for the future of this important area.

We conducted a review of the wildlife conservation literature to identify broad trends in the pub... more We conducted a review of the wildlife conservation literature to identify broad trends in the publishing record and focal areas of research over the past 20 years. A total of 5,853 papers were reviewed with an emphasis on decadal changes between 1993, 2002, and 2012. For each paper we identified the journal and common keywords, and also determined the research scope, conservation issues and applications, and geographic focus. We found that both the eScholarship provides open access, scholarly publishing services to the University of California and delivers a dynamic research platform to scholars worldwide. numer of journals publishing in the field, as well as the number of published articles, has increased significantly over time. The proportional contribution of the most prominent journals in the field has decreased over time, but not the importance of the articles within those journals. Previously reported biases in the literature towards mammlas and birds persisted in our study, leaving large proportions of globally threatened taxa (e.g. amphibians) underrepresented. There was als a disparity in the number of publications from particular geographic regions, however the proportional contribution of under-represented geographic regions (e.g. Central & South America) increased over time. Finally, using the prevalence of keywords, we identified wildlife/adaptive management, hunting/bushmeat, and human wildlife conflict as contemporary (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) research priorities. The persistence of biases towards charismatic taxa can hinder conservation efforts, and we suggest that researchers refocus their efforts towards vulnerable regions and taxa in order to better address conservation priorities.

Bioko Island, Equatorial Guinea, is home to a diverse assemblage of anthropoid primates, making i... more Bioko Island, Equatorial Guinea, is home to a diverse assemblage of anthropoid primates, making it one of the most important places in Africa for primate conservation. The only threat to the persistence of these primates on Bioko is illegal bushmeat hunting. Since October 1997, the rate of primate carcasses in the central market in the capital, Malabo, has increased significantly, with over 41,000 primates recorded through December 2012. However, the relationship between market dynamics and the status of wild populations is poorly documented and difficult to quantify. This is due, in part, to a lack of island-wide survey data, which detracts from the accuracy of both the population and range estimates of Bioko's monkey species. For instance, the range of the Critically Endangered, endemic Pennant's red colobus (Procolobus pennantii) is currently divided into what are believed to be two isolated populations: a core range in the southwest corner of Bioko, and an unconfirmed population in the Iladyi River valley (IRV) to the southeast. This study investigated the presence of P. pennantii in the IRV region and assessed the status of remaining monkey populations. We also evaluated temporal changes in the relative abundance and proportional representation of monkey species in the IRV region relative to surveys conducted in the same region in 2007. Although not proving its absence, we found no evidence of P. pennantii in the region, suggesting that the Iladyi population may be extirpated. Each of the other five monkey species known to these habitats were encountered, though primate abundance in the IRV region decreased since 2007, concurrent to an increase in hunting in the region. Our results suggest that the primate community may also be undergoing a compensatory shift towards smaller-bodied monkeys (Cercopithecus spp.), as larger species like P. pennantii are being hunted out. Effective enforcement of existing legislation to achieve a decrease in hunting is critical to the long term future of the primates of Bioko.

International Journal of Comparative Psychology, 2014

Conservation Technology

Arctic, Antarctic, and Alpine Research, 2014

PeerJ, 2016

Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in t... more Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in the center of the Gulf of Guinea Pleistocene refugium. The associated forests and highlands along the southern Nigerian-Cameroon border and on the island of Bioko, known as the Biafran forests and highlands, are important formations of the Cameroon
Volcanic Line owing to their wide elevational range, and on Mount Cameroon, a continuous gradient of unbroken vegetation from sea level to over 4000 m. The montane zones
in the region begin 800 m above sea level forming the critically endangered Mount Cameroon and Bioko Montane Forests ecoregion.