Lemur species-specific metapopulation responses to habitat loss and fragmentation

Steffens, Travis S.; Lehman, Shawn M.

doi:10.1371/journal.pone.0195791

Cited by 37 publications

(58 citation statements)

References 74 publications

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“…Lemur sources: a, Brenneman et al (2012); b, encounter rate only: Craul et al. (2009); c, trap success only: Farris et al (2014); d, Ganzhorn (2003); e, population size only: Ganzhorn et al (2000); f, Marrocoli et al (2013); g, pres/abs of only one species: Miller et al (2017); h, Norscia (2008); i, population size only: Norscia and Palagi (2011); j, trap success only: Ramanamanjato and Ganzhorn (2001); k, Randrianambinina et al (2010); l, encounter rate only: Schüßler et al (2018); m, Seiler et al (2013); n, Steffens and Lehman (2018); o, Steffens and Lehman (2019).…”

Section: Resultsmentioning

confidence: 99%

“…Five lemur studies used modeling approaches, with three modeling the manipulation of fragmented landscapes. These studies examined the influence of forest patch removal (Bodin et al, 2006; Estrada & Bodin, 2008; Steffens & Lehman, 2018) and increasing interpatch distance on lemur persistence in fragments by species and on lemur dispersal ability due to landscape connectivity (Steffens & Lehman, 2018). Bodin et al (2006) tested the impact of patch removal on the lemur ecosystem service of seed dispersal, emphasizing the importance of small patches.…”

Section: Resultsmentioning

confidence: 99%

“…Bodin et al (2006) tested the impact of patch removal on the lemur ecosystem service of seed dispersal, emphasizing the importance of small patches. Across a landscape of 42 fragments in northwestern Madagascar, simulations removing the five largest fragment patches resulted in decreased incidence probability for all species modeled, including the extinction of the western fat‐tailed dwarf lemur ( Cheirogaleus medius ) at the study landscape (Steffens & Lehman, 2018). Although few declines were reported when the five most‐connected were removed, the majority of species modeled ( n = 3 of 4) were impacted by removing the five least‐connected (Steffens & Lehman, 2018).…”

Section: Resultsmentioning

confidence: 99%

“…Across a landscape of 42 fragments in northwestern Madagascar, simulations removing the five largest fragment patches resulted in decreased incidence probability for all species modeled, including the extinction of the western fat‐tailed dwarf lemur ( Cheirogaleus medius ) at the study landscape (Steffens & Lehman, 2018). Although few declines were reported when the five most‐connected were removed, the majority of species modeled ( n = 3 of 4) were impacted by removing the five least‐connected (Steffens & Lehman, 2018). Concerning altered isolation distances, no declines were observed when the five largest fragments were separated, while declines within each of the smallest fragments occurred when they were separated (Steffens & Lehman, 2018).…”

Section: Resultsmentioning

confidence: 99%

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Trends in forest fragment research in Madagascar: Documented responses by lemurs and other taxa

Kling

Yaeger

Wright

2020

American J Primatol

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The rise in research investigating fragmentation and its impact on primates and other taxa reflects the growing presence of fragmented landscapes themselves. Although numerous studies report the negative effects of fragmentation on biodiversity, it is difficult to generalize responses to fragmentation for specific taxonomic groups, such as non-human primates, when studies have not employed a definitive concept of fragmentation or fragments themselves. Madagascar's high degree of fragmentation, wealth of endemic taxa, and extensive history of ecological research provide the opportunity to compare fragmentation studies across similar contexts. We conducted a literature search of peer-reviewed articles on fragmentation in Madagascar to characterize its trends. A total of 70 articles, 46 of which concentrated on lemurs, tested the impacts of fragmentation on Malagasy taxa, while additional sources conducted research in one or more fragments without testing its effects (n = 112 total, 79 on lemurs). Studies on lemurs most frequently tested fragmentation's impacts on genetics and biodiversity metrics (n = 16 and 15 studies, respectively), although health, modeling, behavioral, and cross-disciplinary techniques were also reported. Responses to fragmentation were reported for 49 lemur species, with most studies concentrated in eastern Madagascar (87%). Although there was variation in the metrics reported in studies testing the effects of fragmentation on Malagasy species, the most common measures were fragment area, isolation, or comparison to a control site. Landscape-scale approaches and examination of fragmentation per se were rarely employed. Characterizing trends of fragmentation research in Madagascar emphasizes the challenges of documenting fragmentation's effects while highlighting the benefits of research within fragmented landscapes, particularly when combined with consideration for how the matrix within human-modified landscapes may impact primate populations. K E Y W O R D S forest fragments, fragmentation, lemurs, literature search, Madagascar

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Trends in forest fragment research in Madagascar: Documented responses by lemurs and other taxa

Kling

Yaeger

Wright

2020

American J Primatol

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“…We want to highlight that these landscapes are distinctively different from those in other ecoregions of the island. In northern and northwestern Madagascar, for example, at least some lemur species (used here as indicators, Muldoon & Goodman 2015) appear to be able to maintain population connectivity among forest fragments that are embedded in a rather open Savannah matrix (e.g., Quéméré et al 2010;Salmona et al 2015;Aleixo-Pais et al 2018;Steffens and Lehman 2018). Although less studied in the humid ecoregion, it is much more difficult for lemurs and other forest-dwelling species to migrate through the degraded areas of secondary vegetation (Nunziata et al 2016;Schüßler et al 2018b;Galán-Acedo et al 2019).…”

Section: Recent Forest Cover Developments and Determinantsmentioning

confidence: 99%

Identification of crucial stepping stone habitats for biodiversity conservation in northeastern Madagascar using remote sensing and comparative predictive modeling

et al. 2020

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Madagascar is a global biodiversity hotspot of conservation concern. The decline of natural forest habitats due to shifting cultivation has been one of the major land use changes during the last decades. We analyzed satellite images between 1990 and 2018 from northeastern Madagascar to evaluate the contribution of nine variables (e.g., topographic, demographic, forest protection) to explain past forest loss, predict future deforestation probabilities to define important areas that require further conservation attention. Forest cover declined by 21% since 1990 and the once continuous rain forest belt of the region is disrupted twice, in the center and at the southern limit of the study region. Status of forest protection and proximity to the forest edge were identified as most important predictors, but all variables contributed to explaining the observed pattern of deforestation. At least 20% of the 3136 villages in the area were established since 1990 at the expense of previously forested areas. This housing sprawl was mainly driven by accessibility, decreasing landscape connectivity. To conserve the unique biodiversity of the region, the expansion of protected forests and active reforestation measures are urgently needed. Sustainable land use planning and forest management integrating the needs of local land users and conservation priorities should be promoted. We see the highest potential for external stakeholders (e.g., national NGOs) to implement targeted interventions embedded in community-based approaches. Our land cover maps and predictive modeling highlight crucial areas that could act as stepping stone habitats for dispersing or retreating species and therefore important locations to intensify conservation measures.

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Species‐area relationships of lemurs in a fragmented landscape in Madagascar

Steffens

Lehman

2019

American J Primatol

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We used species-area relationships (SARs) to investigate the effects of habitat loss on lemur biogeography. We measured species richness via visual surveys on line transects within 42 fragments of dry deciduous forest at the Ambanjabe field site in Ankarafantsika National Park, Madagascar. We measured human disturbance and habitat characteristics within 38 of the 42 fragments. We measured the distance between each fragment and the nearest settlement, continuous forest, and nearest neighboring fragment. We fit 10 candidate SAR models to the data using nonlinear least squares regression and compared them using Akaikeʼs Information Criterion (AIC). To determine how habitat characteristics, as well as area, influenced species richness, we ran a hierarchical partitioning procedure to select which variables to include in generalized additive models (GAMs) and compared them using AIC.Contrary to expectations, we found that lemurs form convex SARs, without a "small island effect", and with the power model being the most likely SAR model. Although we found that four variables (area, survey effort, and total human disturbance, and mean tree height) independently contributed greater than 10% of the variation in lemur species richness, only area was included in the most likely model. We suggest that the power model was the most likely SAR model and our inability to detect a "small island effect" are the result of Microcebus spp. being edge tolerant and capable of dispersing through matrix, scale issues in the study design, and low γ-diversity in the landscape. However, more study is needed to determine what role human disturbance plays in influencing species richness in lemurs. K E Y W O R D Sarea, habitat loss, patches, power model, sigmoidal model

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Lemur species-specific metapopulation responses to habitat loss and fragmentation

Cited by 37 publications

References 74 publications

Trends in forest fragment research in Madagascar: Documented responses by lemurs and other taxa

Trends in forest fragment research in Madagascar: Documented responses by lemurs and other taxa

Identification of crucial stepping stone habitats for biodiversity conservation in northeastern Madagascar using remote sensing and comparative predictive modeling

Species‐area relationships of lemurs in a fragmented landscape in Madagascar

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