Predicting future conservation needs can help inform conservation management but is subject to uncertainty. We measured deforestation rates during 2015–2017 for 114 protected areas in Madagascar, linked deforestation to the status of protection according to IUCN categories I–VI, used recent deforestation rates to extrapolate forest cover over 2017–2050 and linked the size of forest blocks to the projected persistence of lemur subpopulations. In the six IUCN categories for protected areas in Madagascar the median size of forest blocks is 9–37 km2 and median annual deforestation rates range from 0.02% in the single IUCN category III site to 0.19% in category II and 1.95% in category VI sites. In 2017, 40% of all forest blocks within protected areas were < 10 km2, and this is projected to increase to 45% in 2050. Apart from these small forest fragments, the modal site of forest blocks was 160–320 km2 in 2017, and this is projected to decrease to 80–160 km2 in 2050. The range of > 50% of all lemur species exclusively contains forest blocks of < 10 km2. The modal size of forest blocks > 10 km2 is predicted to remain at 120 km2 until 2050. Although uncertainty remains, these analyses provide hope that forest blocks within the protected areas of Madagascar will remain large enough to maintain lemur subpopulations for most species until 2050. This should allow sufficient time for the implementation of effective conservation measures.

A range of endemic and protected vertebrate species from Madagascar are threatened by the demand for bushmeat. We report on the number of discarded carapaces from illegally killed Critically Endangered radiated tortoises Astrochelys radiata in an urban centre in south-west Madagascar. Through covert monitoring of public rubbish dumps we observed 1,913 carapaces during July 2010–January 2014. There was notable spatial and temporal variation, with some evidence of peaks in carapace dumping during May–June and October–December. A single rubbish dump near the artisanal fishery landing beaches accounted for 93% of the observed carapaces.

Deforestation is one of the most important conservation problems in tropical developing countries, even though cost–benefit analyses consistently show that forest conservation is economically beneficial. In Madagascar, deforestation continues at alarming rates despite numerous initiatives of international donors to increase incentives for local households to support forest conservation. In this literature review, we contrast cost–benefit analyses for forest conservation with: (1) the actual burdens and (2) the actual gains of forest conservation for rural households, generated mainly in the context of conservation projects. We show that approaches to generating direct benefits deliver less value than expected for rural communities; the benefit transfer mechanisms are insufficient as the majority of benefits are captured by other stakeholders, and increased benefit transfer is limited by structural and institutional limitations in local communities, valuation chains and in terms of governance failure at higher levels.

In many developing countries, people rely on natural resources for subsistence and cash income. The trade ban on species listed as critically endangered by the International Union for the Conservation of Nature (IUCN) Red List may be counter-productive, as increasing the rarity and thus price of these species acts as a stimulus to illegal markets rather than a deterrent. Since illegal markets cannot have legal property rights, there is no basis for any form of sustainable harvesting based on property rights. The Malagsy radiated tortoise (Astrochelys radiata) is an example of a species that is threatened by domestic and international trade; legalizing international trade could, under certain circumstances, provide financial incentives that might effectively reduce the domestic trade and subsistence harvest of this animal. This paper argues this critically-endangered species may be more effectively conserved by assigning trading rights to local communities, rather than demanding a trade ban that cannot be enforced successfully.

Interactions among fleshy fruits and frugivore assemblages are presented from a 1-y study in the littoral forest of Sainte Luce, south-eastern Madagascar. This community-level approach allowed us to determine food selection by all consumer species and to evaluate the role different frugivores play in seed dispersal and predation. For this, interactions between 136 consumed fruit species and 13 frugivorous species were studied. Fruit and seed size were the most important physical factors determining food selection of all consumer species. Nutritionally birds favoured and mammals avoided lipid-rich fruits. For Cheirogaleus spp., that go into torpor, there was a trend to select sugar-rich fruit pulp. However, for numerous fruit traits the consumer species had no clear feeding preferences and they seemed to be quite flexible, eating whatever was available. This might be related to unpredictable fruit availability and low fruit productivity in the littoral forest, which may also partially explain the low number of frugivores present. Nevertheless frugivores have different impacts on seed dispersal. Eulemur fulvus collaris is particularly important for the dispersal of large-seeded species, while frugivorous birds and flying foxes ensure plant regeneration between and outside forest fragments. In terms of conservation, heterogeneous seed transport is particularly important for this severely degraded littoral forest.

Monomorphic lemurs of Madagascar allow us to investigate whether there are behavioural mechanisms that compensate for sex-specific differences in the costs of maintenance and reproduction in arboreal primates. Food selection of the pair-living Lepilemur ruficaudatus was studied in relation to food chemistry, and travel distances were measured as possible indications of differential investment in ranging activities (possibly related to the defence of territories and/or mating opportunities). Fourteen females and 14 males were radio-tracked for a total of 365 half-nights (from dusk to midnight or from midnight to dawn) at different times of the year (birth, lactation and weaning, pre-mating, post-mating). When based on monthly means, the two sexes did not differ in nightly travel distances. Food selection of females and males did not differ in relation to the chemical composition of leaves, but fruits consumed by females had lower fibre contents than fruits consumed by males. Even though other behavioural data are fragmentary, little evidence exists for behavioural mechanisms in L. ruficaudatus to compensate for the different energetic costs of females and males.

Studies on the effects of nonindigenous invasive species and habitat fragmentation on native ecosystems have become priorities for conservation biologists. This is relevant particularly for islands with high degrees of endemism. In the present paper the role of fragmentation and possible effects of introduced Rattus rattus on endemic rodents (Macrotarsomys bastardi and Eliurus spp.) and the gray mouse lemur (Microcebus murinus) were assessed for dry deciduous forests in Madagascar. Capture rates of endemic rodents declined significantly with declining fragment size. Macrotarsomys bastardi was never caught in primary forest fragments < 600 ha or outside the primary forest but captures of M. bastardi were correlated to changes in vegetation structure associated with fragmentation rather than to fragment size per se. Eliurus spp. were also found in small primary-forest fragments and in secondary forests close to primary forests, suggesting that secondary forests can serve as buffer zones or corridors for this species. The lemur M. murinus was caught in all types of primary and secondary forest. This species did not seem to respond to fragmentation of primary forests. Even though it was found in most secondary-forests, capture rates declined as these secondary forest formations increased in size. This indicates that secondary forests are suboptimal habitats for M. murinus. Rattus rattus were caught in all vegetation formations except for the open savanna. Their capture rates increased as forest fragments became smaller, indicating that mosaics of different habitat types are beneficial for introduced rats. There was no significant relation between capture rates of R. rattus and the endemic species. In conclusion, these results suggest that (1) native Malagasy rodents of the dry deciduous forest are more sensitive towards forest disturbance than M. murinus;(2) there is no indication for negative interactions between introduced rats and the native small-mammal fauna.

Madagascar is renowned not only for its high biodiversity and high degree of endemism, but also for ongoing loss of the original primary vegetation. Here we draw attention to the critical degree of vulnerability of Madagascar's littoral forest, western dry deciduous forest, and evergreen forests of the high plateau. Conservation efforts in these forest formations have been low compared to those in the evergreen rainforest of eastern Madagascar. Due to their fragmented nature these ecosystems urgently require reinforced conservation programmes.

We sought to assess the effects of forest fragmentation, introduced Rattus rattus, exotic tree plantations and secondary vegetation on the endemic rodent Eliurus webbi (Nesomyinae) and the lemur Microcebus murinus in the littoral forests of southern Madagascar. For E. webbi the number of individuals caught, the body mass of males and the percentage of females in the population were positively correlated with the size of the forest fragments. Capture rates and population characteristics of the other two species were uncorrelated with fragment size. None of the endemic species was caught outside the native forest while R. rattus inhabited all vegetation formations except for a newly planted corridor of tree saplings. Capture rates of both endemic species were uncorrelated with the number of R. rattus caught at the same site and thus did not indicate replacement of native species by R. rattus. The study demonstrated negative effects of fragmentation on capture rates of E. webbi and changes in their population characteristics. Exotic tree plantations or secondary vegetation seem to represent unsuitable or marginal habitats for the endemic species.

The goal of this study was to investigate whether or not beavers Castor fiber albicus improve the quality of their food plants by dam construction, resulting in periodic flooding associated with the deposition of mud and nutrients on their feeding grounds. For this, food selection of beavers was studied in relation to plant chemicals in the Spessart mountains (central Germany). The concentrations of the preferred plant chemicals were compared between individuals of the same plant species growing in areas that were flooded periodically and areas that were edaphically dry. Plants eaten by beavers contained higher concentrations of nitrogen and lower concentrations of neutral detergent fibre and hemicellulose than neighbouring plants that were not eaten. Neither nitrogen concentrations nor neutral detergent fibre contents differed significantly between plants from the dry and wet sites. Thus, beaver activities did not improve the chemical quality of their food plants.