Remaining forests on the Central Highlands of Madagascar—Endemic and endangered aquatic beetle fauna uncovered

Abstract

Madagascar is known for its high endemism and as many as 90% of this unique diversity are forest‐dwellers. Unfortunately, the forest cover of Madagascar is decreasing at an alarming rate. This decrease can also affect aquatic insects, but our knowledge on aquatic insect diversity and distribution on Madagascar are limited. Although the eastern rainforests are considered the most diverse, the Central Highlands of Madagascar also harbors unique microendemic fauna but has been less studied. Here, we analyze the aquatic Adephaga beetle fauna of three remaining protected forests of the Central Highlands. Diversity, abundance, and uniqueness are compared between and within natural forests and surrounding grasslands. At least 15 undescribed species were found, highlighting the Central Highlands as an important area for endemism. The natural forests and the surrounding grasslands differed significantly in species assemblages. Interestingly, the three remaining forests differed in their assemblages with the geographically more distant Manjakatompo Ankaratra having the most unique fauna but also the highest altitude span. By contrast, the species composition was similar between the peripheral zones of each of the three remaining forests. The similarity of the fauna in the peripheral open habitats illustrates how some local forest endemics are replaced with widespread generalists in degraded habitats. Our study shows that the remaining forests of the Central Highlands of Madagascar are important refuges of unique fauna at high risk of extinction.

An open source, remote sensing‐based methodology for wetland habitat condition assessments to aid conservation decision‐making

“…low levels of vegetation burning, deforestation and fishing) (Woolaver et al., 2014). Madagascar has lost 60% of its highland wetland coverage since 1960, with agriculture and grassland now the main regional land use and habitat types (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012; Ranarilalatiana et al., 2022). Remaining wetlands retain high levels of biodiversity but are extensively degraded, primarily through conversion for rice cultivation (leading to a decrease in wetland extent) and riparian deforestation (leading to increased soil erosion and siltation) (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012).…”

An open source, remote sensing‐based methodology for wetland habitat condition assessments to aid conservation decision‐making

“…low levels of vegetation burning, deforestation and fishing) (Woolaver et al., 2014). Madagascar has lost 60% of its highland wetland coverage since 1960, with agriculture and grassland now the main regional land use and habitat types (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012; Ranarilalatiana et al., 2022). Remaining wetlands retain high levels of biodiversity but are extensively degraded, primarily through conversion for rice cultivation (leading to a decrease in wetland extent) and riparian deforestation (leading to increased soil erosion and siltation) (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012).…”

Small population size and possible extirpation of the threatened Malagasy poison frog Mantella cowanii

“…This region of Madagascar was formerly a mosaic of grassland, woodland, and subhumid forest, covering the mountainous area between the island’s humid east and dryer west ( Yoder et al, 2016 ). Today the central highlands consist mostly of secondary grasses and land converted for subsistence agriculture and cattle grazing, with little humid forest remaining ( Andriambeloson et al, 2021 ; Ranarilalatiana et al, 2022 ). Thirteen localities of M. cowanii are known from the region: six in a cluster around the village of Antoetra, five 80 km northwest on the Itremo Massif, and two isolated localities located >100 km north of all other known populations, one near Betafo and the other east of Antakasina ( Rabibisoa, 2008 ; Rabibisoa et al, 2009 ).…”

An open source, remote sensing‐based methodology for wetland habitat condition assessments to aid conservation decision‐making

“…low levels of vegetation burning, deforestation and fishing) (Woolaver et al., 2014). Madagascar has lost 60% of its highland wetland coverage since 1960, with agriculture and grassland now the main regional land use and habitat types (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012; Ranarilalatiana et al., 2022). Remaining wetlands retain high levels of biodiversity but are extensively degraded, primarily through conversion for rice cultivation (leading to a decrease in wetland extent) and riparian deforestation (leading to increased soil erosion and siltation) (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012).…”

Small population size and possible extirpation of the threatened Malagasy poison frog Mantella cowanii

“…This region of Madagascar was formerly a mosaic of grassland, woodland, and subhumid forest, covering the mountainous area between the island’s humid east and dryer west ( Yoder et al, 2016 ). Today the central highlands consist mostly of secondary grasses and land converted for subsistence agriculture and cattle grazing, with little humid forest remaining ( Andriambeloson et al, 2021 ; Ranarilalatiana et al, 2022 ). Thirteen localities of M. cowanii are known from the region: six in a cluster around the village of Antoetra, five 80 km northwest on the Itremo Massif, and two isolated localities located >100 km north of all other known populations, one near Betafo and the other east of Antakasina ( Rabibisoa, 2008 ; Rabibisoa et al, 2009 ).…”

An open source, remote sensing‐based methodology for wetland habitat condition assessments to aid conservation decision‐making

“…low levels of vegetation burning, deforestation and fishing) (Woolaver et al., 2014). Madagascar has lost 60% of its highland wetland coverage since 1960, with agriculture and grassland now the main regional land use and habitat types (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012; Ranarilalatiana et al., 2022). Remaining wetlands retain high levels of biodiversity but are extensively degraded, primarily through conversion for rice cultivation (leading to a decrease in wetland extent) and riparian deforestation (leading to increased soil erosion and siltation) (Bamford et al., 2017; Broothaerts et al., 2023; Kull, 2012).…”

Small population size and possible extirpation of the threatened Malagasy poison frog Mantella cowanii

“…This region of Madagascar was formerly a mosaic of grassland, woodland, and subhumid forest, covering the mountainous area between the island’s humid east and dryer west ( Yoder et al, 2016 ). Today the central highlands consist mostly of secondary grasses and land converted for subsistence agriculture and cattle grazing, with little humid forest remaining ( Andriambeloson et al, 2021 ; Ranarilalatiana et al, 2022 ). Thirteen localities of M. cowanii are known from the region: six in a cluster around the village of Antoetra, five 80 km northwest on the Itremo Massif, and two isolated localities located >100 km north of all other known populations, one near Betafo and the other east of Antakasina ( Rabibisoa, 2008 ; Rabibisoa et al, 2009 ).…”