Vulnerability of a frugivory community to edge effects in a Malagasy tropical humid forest

Edge effects pose a critical challenge to the long-term survival of animal populations. To establish conservation strategies to prevent further species loss, we need a better understanding of species responses to edge effects and the factors that may influence such responses. We addressed this using a community of frugivores in an evergreen humid forest in eastern Madagascar. We conducted daily and nocturnal animal surveys for a year along five edge-interior transects of up to 2925 m long and measured several critical ecological and environmental factors, namely plant community structure, fruit resource availability, ecosystem productivity, richness of predator species, environmental conditions, and anthropogenic pressures. We found that plant diversity and average temperature significantly affected the species richness of frugivore communities, specifically bird communities. We also found that the richness of lemur communities slightly increased with the distance from the forest edge, and the species richness of non-frugivore communities was associated with predator species richness. Regarding the relative abundance and presence of each frugivore species along the gradient, our data showed that different species responded differently to each factor, some responding negatively or positively, while others were unaffected. These results highlight the importance of species-specific measures for conserving and restoring natural habitats to ensure the viability of frugivore populations. Miteraka olana goavana ho an’ny fahavelomana maharitry ny biby ny fahasimban’ny ala, noho izy mampitombo ny haben’ny sisin’ala izay manana toetra hafa kokoa noho ny atiala. Mba ahafahana manangana paikady matanjaka ho fisorohana ny faharinganan’ny karazam-biby iray, indrindra ireo izay tena marefo sy ahiana ho lany tamingana, dia ilaina ny mamantatra ny fiantraikan’ny toetoetry ny sisin’ala amin’ny biby. Niompana tamin’ireo biby mpihinam-boa any amin’ny faritra atsinanan’i Madagasikara ity fikarohanay ity, nanadihadiana izay mety ho antony mahatonga ny fiovan’ny fiainan’ny biby isan-karazany manoloana ny sisin’ala. Nanoritra lalana mahitsy dimy, mirefy hatramin’ny 2925 metatra nanomboka teo amin’ny sisin’ala ka namakivaky ny atiala izahay nijerevana sy nanisana ireo biby misy ao. Nandrefy ireto singa manaraka ireto ihany koa izahay: ny isa sy ny firafitr’ireo hazo hita ao anaty toeram-ponenan’ireo biby, ny fahabetsahan’ny voankazo eo aminy, ny famokaran’ny rohiaina, ny isan’ireo karazam-biby mpihaza an’ireo biby mpihinam-boa, ny mari-pàna sy hamandoan’ilay toerana ary ny tsindry ataon’ny olombelona aminy. Ny vokatry ny fikarohana dia mampiseho fa ny karazan-javamaniry sy ny mari-pàna dia miteraka voka-dratsy ho an’ireo vondron’ny biby mpihinam-boa rehetra (vorona sy varika). Ho an’ireo vondrona misy ny vorona manokana ihany koa dia hita fa ny karazan-javamaniry sy ny mari-pàna no miteraka voka-dratsy ho azy ireo. Ho an’ireo vondrona misy ny varika manokana indray dia ahitana fiakarany kely ny isan’izy ireo rehefa manalavitra ny sisin’ala. Ary ny isan’ireo vondrom-biby tsy mpihinam-boa dia ahitana fiakarana rehefa mitombo ny isan’ireo biby mpihaza azy sy ireo tsindry mihatra aminy. Ho an’ireo biby mpihinam-boa kosa indray anefa dia hita fa tsy mitovy ny fihetsik’izy ireo tsirairay manoloana ireo anton-javatra isan-karazany ireo. Ao ny mampiseho fitomboan’isa, ao ireo mihavitsy, ary ao koa ireo tsy misy fiovana akory. Ireo voka-pikarohana ireo dia mampiseho ny maha zava-dehibe ny fandraisana fepetra ho an’ny karazam-biby tsirairay fa tsy faobe, satria tsy mitovy ny fihetsika avalin’izy ireo amin’ny fiantraikan’ny sisin’ala. Izany dia mba ahafahana miaro sy manarina ny fonenana natoraly misy ireo biby ireo mba ahafahan’izy ireo monina maharitra ao anaty ala.