@article{DammhahnRakotondramananaGoodman2015,
  author    = {Dammhahn, Melanie and Rakotondramanana, Claude Fabienne and Goodman, Steven M.},
  title     = {Coexistence of morphologically similar bats (Vespertilionidae) on Madagascar: stable isotopes reveal fine-grained niche differentiation among cryptic species},
  series = {Journal of tropical ecology},
  volume    = {31},
  journal   = {Journal of tropical ecology},
  publisher = {Cambridge Univ. Press},
  address   = {New York},
  issn      = {0266-4674},
  doi       = {10.1017/S0266467414000741},
  pages     = {153 -- 164},
  year      = {2015},
  abstract  = {Based on niche theory, closely related and morphologically similar species are not predicted to coexist due to overlap in resource and habitat use. Local assemblages of bats often contain cryptic taxa, which co-occur despite notable similarities in morphology and ecology. We measured in two different habitat types on Madagascar levels of stable carbon and nitrogen isotopes in hair (n = 103) and faeces (n = 57) of cryptic Vespertilionidae taxa to indirectly examine whether fine-grained trophic niche differentiation explains their coexistence. In the dry deciduous forest (Kirindy), six sympatric species ranged over 6.0\% in delta N-15, i.e. two trophic levels, and 4.2\% in delta C-13 with a community mean of 11.3\% in delta N-15 and - 21.0\% in delta C-13. In the mesic forest (Antsahabe), three sympatric species ranged over one trophic level (delta N-15: 2.4\%, delta C-13: 1.0\%) with a community mean of 8.0\% delta N-15 and - 21.7\% in delta C-13. Multivariate analyses and residual permutation of Euclidian distances in delta C-13- delta N-15 bi-plots revealed in both communities distinct stable isotope signatures and species separation for the hair samples among coexisting Vespertilionidae. Intraspecific variation in faecal and hair stable isotopes did not indicate that seasonal migration might relax competition and thereby facilitate the local co-occurrence of sympatric taxa.},
  language  = {en}
}
@article{DammhahnRandriamoriaGoodman2017,
  author    = {Dammhahn, Melanie and Randriamoria, Toky M. and Goodman, Steven M.},
  title     = {Broad and flexible stable isotope niches in invasive non-native Rattus spp. in anthropogenic and natural habitats of central eastern Madagascar},
  series = {BMC ecology},
  volume    = {17},
  journal   = {BMC ecology},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1472-6785},
  doi       = {10.1186/s12898-017-0125-0},
  pages     = {13},
  year      = {2017},
  abstract  = {Background: Rodents of the genus Rattus are among the most pervasive and successful invasive species, causing major vicissitudes in native ecological communities. A broad and flexible generalist diet has been suggested as key to the invasion success of Rattus spp. Here, we use an indirect approach to better understand foraging niche width, plasticity, and overlap within and between introduced Rattus spp. in anthropogenic habitats and natural humid forests of Madagascar. Results: Based on stable carbon and nitrogen isotope values measured in hair samples of 589 individual rodents, we found that Rattus rattus had an extremely wide foraging niche, encompassing the isotopic space covered by a complete endemic forest-dwelling Malagasy small mammal community. Comparisons of Bayesian standard ellipses, as well as (multivariate) mixed-modeling analyses, revealed that the stable isotope niche of R. rattus tended to change seasonally and differed between natural forests and anthropogenic habitats, indicating plasticity in feeding niches. In co-occurrence, R. rattus and Rattus norvegicus partitioned feeding niches. Isotopic mismatch of signatures of individual R. rattus and the habitat in which they were captured, indicate frequent dispersal movements for this species between natural forest and anthropogenic habitats. Conclusions: Since R. rattus are known to transmit a number of zoonoses, potentially affecting communities of endemic small mammals, as well as humans, these movements presumably increase transmission potential. Our results suggest that due to their generalist diet and potential movement between natural forest and anthropogenic habitats, Rattus spp. might affect native forest-dependent Malagasy rodents as competitors, predators, and disease vectors. The combination of these effects helps explain the invasion success of Rattus spp. and the detrimental effects of this genus on the endemic Malagasy rodent fauna.},
  language  = {en}
}