Terrestrial ecosystems


Madagascar is globally recognized as an island of exceptional biodiversity. With more than 90% endemism amongst species of plants, mammals, reptiles and amphibians, numerous species that are found in Madagascar are found nowhere else on earth. However, human activities are threatening the ongoing survival of this natural legacy. Deforestation, predominantly for agriculture, has resulted in a loss of approximately 90% of the island’s original forest cover, and what remains is highly fragmented. Climate change is compounding existing stresses on ecosystems and is considered by many researchers to be the future major threat to the survival of numerous unique species found here. Adaptation to climate change to protect terrestrial ecosystems must therefore be at the core of the overall national response to climate change.

Potential Impacts of Climate Change

Some species and ecosystems in Madagascar are already exhibiting responses to a changing climate; for example a decrease in lemur survival linked to drier winters in Ranomafana National Park has been observed. Climate change impacts on terrestrial ecosystems are likely to intensify in the future and occur as a result of both climate variability and extreme climate events. Effects will be felt at the population, species and ecosystem level but the nature and scale of the impacts will not be equal. Potential impacts include:
• Changes in species range and distribution including expansion or contraction of range and range shifts along altitudinal or moisture gradients. Recent modeling has predicted that of 74 plant species studied in Madagascar, 18% are expected to expand in range, 45% are expected to contract in range and 37% showed a mixed response. While responses of species vary widely, species that are confined to narrow habitats are generally likely to be more severely impacted. Migration may be essential for some species where future predicted distributions have limited overlap with existing distributions. The ability of species to migrate is however threatened by the fragmented nature of remaining habitats.

• Genetic and evolutionary effects as animal and plan populations experience new selection pressures due to changing climate conditions or changing ecosystem composition. Climate change has been identified by some researchers to be the dominant influence on evolutionary processes in the coming centuries.

• Phenological effects such as changes in breeding seasons, flowering seasons, life cycles, migration patterns, emergence timing or metamorphic patterns are possible. Species that do not undergo direct phenological changes may be indirectly affected by changes in species upon which they rely; for example availability of food sources may change with change in budding and fruiting periods of plants.

• Ecosystem composition is likely to change as different species within existing ecosystems react differently to climate stressors. Extinction of some species within ecosystems is possible due to increased competition for available habitat niches. Invasive species with the ability to withstand a wide range of climate conditions may overwhelm ecosystems.

• Physical damage or harm to species and ecosystems can result directly from climate variability or climate extremes. For example changes in precipitation may affect vegetation growth or access to water sources for animals. Impacts can also be caused indirectly from the secondary effects of climate change. For example, erosion of already deforested lands is likely to be increased as a result of changing precipitation and the resulting loss of soil fertility may affect vegetation.

• Impacts from changes in the hydrological cycle on riverine ecosystems which can be affected by flow rates, river levels, and groundwater recharge rates.

• Increased pressure on natural resources resulting from changes in demand for ecosystem goods and services by local communities. Poor and vulnerable populations in Madagascar are highly reliant on natural resources provided by terrestrial ecosystems (e.g. fuel wood, foodstuffs, medicinal plants etc.). Current levels of resource use are at, or are reaching, unsustainable levels in some areas and pressures could be exacerbated by increased demand resulting from climate-induced migration, or households being forced into poverty by climate change impacts.

• Loss of habitat and loss of connectivity between habitats resulting from one or more of the potential impacts described above. Modeling has indicated that in the next 100 years Madagascar could lose 11-27% of its current habitat assuming perfect dispersal, and 17-50% if no dispersal is assumed. Loss of connectivity between areas of suitable habitat through is particularly of concern as the main response of certain species to climate change may be migration, which will not be possible for most species without physical connections between habitat areas.

Priority Actions for Adaptation to Climate Change

Climate change adaptation measures are required to increase the resilience of terrestrial ecosystems, and the goods and services they provide, to future climate conditions. Examples of adaptation approaches that should be considered for implementation include:
• Further research into specific impacts on high priority species and ecosystems to better understand the priority threats of climate change on populations, species and ecosystems and dissemination of results of research to a wide audience in order to raise awareness about the effects of climate change on biodiversity.

• Ongoing extension, reinforcement and improved management of protected area network including expansion of the network to improve representation and replication and facilitate conservation of priority population, species and ecosystems identified as being at risk of climate change effects; inclusion of corridors and connective habitat in the network where possible; improved focus of network management on ecosystem function; development of adaptive management frameworks to respond to the identified effects of climate change; and improved management and enforcement of the network to reduce the effects of non-climate stressors.

• Development of a comprehensive monitoring system within protected areas for climate change impacts to allow early warning of impacts and potential tipping points within ecosystems and facilitate adaptative management of protected areas.

• Development of species specific management strategies to focus resources on priority species with a high risk of extinction and including consideration of the feasibility of translocation of species or establishment of captive populations for species at risk of extinction.

• Enhancement of connectivity between fragmented habitats including restoration and protection of riverine corridors for migration of species including identification of key corridors between areas of habitat and implementation of restoration or rehabilitation activities; improvement of institutional management and monitoring frameworks for corridors through development of landscape conservation plans; and involvement of local communities in restoration, rehabilitation and monitoring activities. Riverine corridors have been identified as being of particular importance for dispersal of species and should be a focus of adaptation strategies.

• Management of forest areas outside the protected area network to allow for ongoing sustainable resource use by local communities thereby decreasing pressure on resources within the protected area network.

• Integration of adaptation strategies for biodiversity and socio-economic development to ensure that adaptation strategies developed to increase resilience of terrestrial ecosystems take into account the social issues and include elements to minimize both existing human induced stressors and secondary social effects of climate change (e.g. climate migrants) on biodiversity. Examples include development of programs for sustainable alternative livelihoods for resource dependent communities, establishment of financial incentives for conservation, development of alternative sources of natural resources (e.g. fuel wood plantations on degraded lands).