Thomas E. Lacher | Texas A&M University (original) (raw)

Papers by Thomas E. Lacher

Journal of Mammalogy, 1989

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BioScience, 1988

O n 17 September 1985, Jose Sarney, President of Brazil, declared the Pantanal Matogrossense a pr... more O n 17 September 1985, Jose Sarney, President of Brazil, declared the Pantanal Matogrossense a priority area for research and conservation. This announcement was part of the opening ceremonies of a worldwide campaign directed at the conservation of ...

Revista Brasileira de Zoologia, 1987

The pantanal is one of the world s richest freshwater wetlonds. The pantanal is located in the fl... more The pantanal is one of the world s richest freshwater wetlonds. The pantanal is located in the flood ploin of the headwaters of the Paraguai river, covering 140,000 km 2 • The habitats of the Panfilnal are present in a complex mosaico The major habitat types are: pockets of forests, called capa-o or cordilheira, seasonally flooded grasslands ar campos, and pennanent or temporary logoons, called baías. The Pantanal harbors bothrich and abundant mammal fauna. A survey was conducted atFazenda Nhumirim, a research station run by ·the Centro de Pesquisa Agropecuária do Pantanal (CPAP) in Corumbá, a research branch of EMBRAPA. The Fazenda covers an area of 4,310 ha in the sub-region of Nhecolândia, appoximately 150 km east of Corumbá, Mato Grosso do Sul. The area receives an average annual rainfall of 1,022 mm, and has a mean monthly temperature that varies between 29.1 0 C (January) and 22. 00 C (June). Fourroutes were followed between two times during ten days of each month. The survey routes were covered on horseback by between two and four observers. Each route was followed and equal number of times in the morning and in the afternoon, to eliminate bias reloted to the activity patiems of mammals. ln order to evaluate relotive abundance of nocturnal species, we also conducted a number of nocturnal ,censuses. These censuses were dane by car; a high intensity searchlight was used to spot lhe animais. We also conducted a trap-mark-recapture survey of the small

Biotropica, 2001

ABSTRACT The Amazon Forest and the Cerrado of central Brazil share an extensive zone of integrati... more ABSTRACT The Amazon Forest and the Cerrado of central Brazil share an extensive zone of integration. Each of these major ecosystems remains poorly studied; however, the composition of communities at the contact zone is even less well described. Small ...

Biotropica, 1986

... Drs. KH Redford, ER Heithaus, and an anonymous reviewer made helpful suggestions on the manus... more ... Drs. KH Redford, ER Heithaus, and an anonymous reviewer made helpful suggestions on the manuscript. ... and the Caribbean (NSF Grants BSR-82 13675 and INT -8212576 to MA Mares and a grant from the Conselho Nacional de Pesquisas do Brasil to CJR Alho) and through ...

Aim To examine the taxonomic uniqueness, range sizes, endemism and conservation status of souther... more Aim To examine the taxonomic uniqueness, range sizes, endemism and conservation status of southern temperate zone mammals and how factors impacting their conservation differ across hemispheres.

Aim Every spring endangered Mexican long-nosed bats (Leptonycteris nivalis) migrate up to 1200 km... more Aim Every spring endangered Mexican long-nosed bats (Leptonycteris nivalis) migrate up to 1200 km from central Mexico to southern United States. Evidence suggests that L. nivalis follows the blooms of paniculate agave plants (genus Agave, subgenus Agave). Paniculate agave inflorescences are adapted to attract bats, and studies have indicated that Leptonycteris spp. played a key role in Agave speciation. We test the hypothesis of the Agave migratory corridor by (1) modelling the distribution of the relevant Agave species; and (2) testing whether bat records are significantly related to Agave species richness as predicted by our models. Location Mexico and United States. Methods We selected nine paniculate Agave species based on a set of criteria and modelled the current distribution of those species using MAXENT and the Genetic Algorithm for Rule-set Production (GARP), and geographic information systems to analyse the spatial correspondence of Agave richness and presence of L. nivalis. Results We combined the Agave presence maps that resulted from the models with higher performance to create a richness map. This map indicated up to five species overlapping. L. nivalis occurrence areas correspond with areas with two, three and four Agave species more often than random expectations at the 0.05 significance level. The opposite is observed for areas with 0 Agave species where L. nivalis correspond less often than random. Main conclusions Presence–pseudo-absence and presence–background modelling tools allowed us to map potential Agave presence. These maps could guide conservation actions to ensure the maintenance of this pollination corridor. Areas with higher number of Agave species are distributed along mountain chains and may provide foraging resources for L. nivalis for longer period of time during its migration. We recommend implementing a long-term monitoring programme in those areas to document inflorescence timing in Agave species and the presence of L. nivalis.

The development of standards, data sharing, and initiatives like the Global Biodiversity Informat... more The development of standards, data sharing, and initiatives like the Global Biodiversity Information Facility and others have advanced research in many fields, including in conservation of biodiversity. Global assessments of extinction risk to species have been completed by IUCN for multiple taxa. The IUCN global assessments have had a major impact on conservation science and practice as well as biodiversity funding mechanisms though the Global Environment Facility, the World Bank, and the Critical Ecosystem Partnership Fund (CEPF). A signature of the assessments is a process of sustained interaction between conservation organizations and the research and academic community, effectively integrating science and policy on global scale. The model relies on several critical components: openness of the conservation community to scientific input and debate, engagement of the scientific community, conservation organization mediated data collation, and data sharing with ease of access. This model can be applied to other challenges to conserve biodiversity and assess how biodiversity loss affects the well-being of societies across the world. The recognition of the importance of biodiversity in meeting the Millennium Development Goals and the recognition of the failure to meet the 2010 Biodiversity Target illustrate the gap between what needs to be achieved and our current trajectory.

Summary 1. Although time can be subdivided to promote species coexistence, quantitative examina... more Summary
1. Although time can be subdivided to promote species coexistence, quantitative examination of assemblage-wide temporal niche overlap has seldom been explored with appropriate null models. Because of the sequential and continuous nature of time, it requires a different kind of randomization model than those used to assess subdivision of discrete and non-sequential resources (e.g., food types, microhabitats).
2. For two common niche overlap indices (Pianka and Czekanowski), we compared the responses of two common randomization models and a newly developed model (ROSARIO) to different levels of temporal autocorrelation, specialization and coincidence of activity.
3. Although qualitatively similar results characterized overlap indices, results differed depending on randomization model. Temporal resolution of the data and amount of temporal specialization in an assemblage can have large effects on model outcomes. ROSARIO is as powerful as the models used for analyses of overlap of nominal and unordered resources, but it is more appropriate for ranked and interval data, as it maintains the empirical temporal autocorrelation within species.
4. ROSARIO can be a useful tool for exploration of assemblage-wide patterns of overlap in use of resources that occur as cyclical phenomena, such as diel phases, yearly seasons, lunar tides, and climate oscillations.

Wild rodents (n=248) were trapped in two ecologically distinct sites at El Cielo Biosphere Reserv... more Wild rodents (n=248) were trapped in two ecologically distinct sites at El Cielo Biosphere Reserve in the state of Tamaulipas, Mexico, during the summer of 2003. Samples from 199 individuals were tested for Hantavirus antibodies by an indirect enzyme-linked immunosorbent assay (ELISA). Hantavirus antibodies to recombinant Sin Nombre virus nucleocapsid protein were found in seven rodents (3.5%) of a single species, Peromyscus levipes. Antibody-positive rodents were found only in the Cloud Forest site, which had lower rodent species diversity than the Tropical Subdecidous Forest site. Although the identity of the virus in P. levipes remains to be determined, our study provides further evidence that Hantavirus antibody–positive individuals are prevalent in the rodent fauna of Mexico. This is the first survey for Hantavirus antibodies in the rodent fauna of Tamaulipas and the first report of P. levipes as a potential host for a Hantavirus.

Temporal niche partitioning can be a viable mechanism for coexistence, but has received less atte... more Temporal niche partitioning can be a viable mechanism for coexistence, but has received less attention than other niche axes. We characterized and compared patterns of activity, and overlap of temporal activity among the five common rodent species from a tropical semideciduous forest (TSF) and between the two common rodent species from cloud forest (CF) at El Cielo Biosphere Reserve in Mexico. Capture frequencies over 2-h intervals, obtained via live trapping (6850 trap-nights) in chosen months over 3 y formed the empirical basis for analyses. Trap transects were set from 19h00 to 07h00 and checked every 2 h. Analyses of 484 captures evinced two distinct assemblages. The TSF assemblage was diverse and with non-random temporal niche segregation, whereas the CF assemblage was depauperate with its two dominant species evincing the same activity pattern. Predator avoidance between open- and closed-microhabitat species, as well as niche complementarity may explain temporal segregation at TSF. This is the first documentation of assemblage-wide non-random temporal segregation of neotropical rodents. Time of activity may be a largely under-appreciated mechanism in other species-rich tropical rodent assemblages as well as in other species-rich biotas.

Biotropica, 1986

Biotropica, 2001

BioScience, 1988

Journal of Mammalogy, 1989

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomical... more Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and
distribution of the world’s mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems.
Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.

Bulletin of Environmental Contamination and Toxicology, 1998

Currently, banana plantations occupy more than 50,000 ha of the total lowland area in Costa Rica ... more Currently, banana plantations occupy more than 50,000 ha of the total lowland area in Costa Rica and are confined almost exclusively east of the Cordillera mountain range. Banana cultivation on these plantations represents an intensely managed agroecosystem with high inputs of synthetic chemicals, generally in the form of pesticides and fertilizers. While much emphasis has been placed on estimating pesticide use and potential effects to humans in these plantations , Forget, 1991 little research has examined the distribution, fate, and potential wildlife exposure to agrochemicals used in banana plantations. The objective of this study was to develop methods to estimate pesticide distribution and avian exposure to selected chemicals in banana plantations. To that end, two plantations were compared: one treated with the insecticide carbofuran, the other was not treated with an insecticide. Both plantations received normal fungicide and herbicide applications. Chemical analyses were performed on avian foot wash samples to determine the relative frequency and magnitude of contact exposure and on plantation runoff samples to assess pesticide movement. Plasma cholinesterase activities were determined to establish the degree of carbamate exposure in birds. Our hypothesis was that birds from the plantation treated with carbofuran would have a higher incidence of cholinesterase depression relative to birds from the reference site.

Ecotoxicology, 1999

. Ž . Abstract. Swainson's hawks Buteo swainsoni were observed in the grasslands pampas of Argent... more . Ž . Abstract. Swainson's hawks Buteo swainsoni were observed in the grasslands pampas of Argentina during the austral summer of 1995᎐96. Widespread agrochemical use to control insects had a profound effect on flocks of hawks foraging on grasshoppers and caterpillars throughout the pampas. We describe 19 mortality incidents and an estimated 5,095 dead hawks. Forensic analysis indicated that the organophosphate insecticide monocrotophos was responsible for the deaths at six separate sites, account-Ž . ing for over 4,000 of the mortalities. Brain cholinesterase was lethally inhibited ) 95% and monocro-Ž . tophos residues n s 31r45, mean s 0.20 ppm, range 0.05᎐1.08 ppm were found in the contents of the gastrointestinal tract. No other insecticide residues were found. Sample analyses, combined with interviews with farmers, indicated that monocrotophos was responsible for deaths at 17 of 19 mortality incidents.

Ecotoxicology, 1999

. Abstract. Approximately 6,000 dead Swainson's hawks Buteo swainsoni were discovered in the Pamp... more . Abstract. Approximately 6,000 dead Swainson's hawks Buteo swainsoni were discovered in the Pampas of Argentina in 1995᎐96. Subsequent meetings held between Argentine, US, Canadian, and Swiss Ž . personnel led to an agreement whereby chemical companies removed the organophosphate OP Ž . monocrotophos MCP from the area where mortalities had occurred in northern La Pampa province. We monitored hawks in the MCP exclusion zone from 28 November 1996 through 25 January 1997. We sampled 133 hawks for exposure to anti-cholinesterase insecticides, 131 of which showed no apparent signs of adverse effects. Two hawks had inhibited ChE that recovered over time. Feather and footwash samples from captured birds were tested for OP residues. One feather sample was positive for Ž . dimethoate; no footwash sample was positive for any of the OPs screened. Cholinesterase ChE activities Ž . from hawks in Argentina were mean " SE, n s 131 0.674" 0.014 total ChE, 0.236" 0.006 acetyl-Ž . Ž . cholinesterase AChE , and 0.438" 0.013 butyrylcholinesterase BChE . Mean plasma AChE from Argentine hawks was significantly depressed below North American reference values. Total ChE and BChE activities were not significantly different. Mortality due to OP poisoning was not found in the MCP exclusion zone in northern La Pampa, though it continued outside of the zone where MCP was used, both legally and illegally. Education campaigns and extension efforts, emphasizing the local MCP restrictions, were effective in controlling Swainson's hawk mortalities in the study area where substantial mortality occurred the previous two years.

Journal of Mammalogy, 1989

BioScience, 1988

Revista Brasileira de Zoologia, 1987

Biotropica, 2001

Biotropica, 1986

Biotropica, 2001

BioScience, 1988

Journal of Mammalogy, 1989

Bulletin of Environmental Contamination and Toxicology, 1998

Ecotoxicology, 1999