Research

Research Projects

Nature-based Solutions in Tropical Agroforestry Landscapes

I am currently working on the Flourishing Landscapes Programme (FLP), which addresses the triple challenge of livelihoods, climate change, and biodiversity loss at tropical forest frontiers. FLP uses novel landscape-scale transdisciplinary research, via a network of scientists and practitioners, to investigate strategies to both promote biodiversity and the climate resilience of smallholder farmers. By investigating agroforestry and community-led reforestation as nature-based solutions (NbS), the FLP addresses key knowledge gaps regarding the role of biodiversity in maximising nature’s contributions to people (NCPs) in agricultural landscapes.

FLP focuses on landscapes with agricultural land-use dominated by coffee and cocoa production. In particular, it focuses on agricultural-forest matrix landscapes in three biodiversity hotspots: 1) Napa Province, Ecuador (the Tropical Andes hotspot), 2) Ashanti Region, Ghana, (Guinean Forests of West Africa) and 3) Central Highlands, Viet Nam (Indo-Burma). These landscapes represent forest-frontier areas where agricultural production, particularly cocoa (Ghana and Ecuador) and coffee cultivation (Viet Nam), intersects with severe fragmentation of natural forests.

Conservation Biogeography of the Cheirogaleidae

Habitat destruction, anthropogenic disturbance, and environmental change are among the primary threats to the forests of Madagascar and the endemic lemurs that inhabit them. The Cheirogaleidae are the smallest of all the lemurs, and are particularly vulnerable to forest fragmentation due to their small body size and inability to travel through the open spaces between isolated forest fragments. However, many cheirogaleid lemurs thrive within highly degraded habitats, and it has been hypothesized that this family of lemurs may be somewhat resilient to habitat degradation and anthropogenic threats. Since starting my PhD, I have continued to explore how the demography of the Cheirogaleidae is affected and limited by a range of habitat-related, environmental, and anthropogenic factors, and how the distribution of their forest habitat is likely to be affected by future climate change.

Although my work has been heavily impacted by the Covid-19 pandemic, I have been able to build a large database of cheirogaleid lemur occurrence points and population densities, which I have subsequently used for meta-analyses, and the creation of ecological niche models. My current results suggest that the Cheirogaleidae are resilient and adaptable to environmental change, habitat degradation and anthropogenic disturbance. However, this project has also revealed that habitat-related, environmental, and climatic factors affect the different genera of the Cheirogaleidae interspecifically, and at the species level. Overall, the findings of this project highlight that the Cheirogaleidae are resilient to deforestation, but all lemur species require forest habitats to survive, and continued protection of their habitat is required to ensure their future.

Cryptic Species

Cryptic species are groups of two or more organisms that were previously classified as single nominal species due to their similar appearance. Being almost morphologically indistinguishable, cryptic species have historically been hard to detect, and only modern genetic, morphometric, and molecular analyses enable us to reveal the hidden biodiversity within cryptic species complexes. Cryptic species diversity is now widely acknowledged, but unlike more charismatic and more easily recognisable species, biologists face specific challenges when studying cryptic organisms and protecting their wild populations.

I am working with a network of collaborators to 1) resolve and disentangle known cryptic complexes of nocturnal primates and bats, 2) assess where known cryptic species occur geographically to inform their conservation, and 3) predict how cryptic species may respond to ongoing habitat loss and climate change. This work provides important information on drivers of cryptic speciation, and it enhances our understanding of current and future biodiversity patterns. Further, this work improves our knowledge of understudied and highly threatened animals that are difficult to study, whilst also facilitating applied conservation of their populations.

Seismic Communication of African Elephants

Elephants are intelligent, highly social animals that have a large repertoire of different vocalisations that they use to communicate with conspecifics. However, we still know little about certain vocalisation types, including the infrasonic rumble. Elephant rumbles are high amplitude and low-frequency, and they are particularly interesting as they can generate both an acoustic and seismic component. The elephants themselves are physiologically adapted to both hear these sounds via their enlarged malleus, and to detect their vibrations via their feet and sensitive trunk tips. Elephants also exhibit specific behaviours that are hypothesized to aid in their detection of these vibrations. Seismic components of rumbles alone are already known to trigger behavioural responses in wild elephants independently to the acoustic component, which signifies that seismic rumbles are used to convey information. However, whilst we can localise and study acoustic and seismic rumbles, we do not yet know if both components contain the same information, whether these two components are redundant or complimentary, and if there are benefits to this bimodal communication.

This project is investigating how and why African Elephants (Loxodonta africana) use seismic communication. The specific objectives are to 1) understand how seismic and acoustic components of elephant rumbles propagate in the natural environment, 2) understand the biological importance of seismic and acoustic communication in elephants, and 3) develop real-time capability of elephant monitoring and acoustic sensory systems that can detect elephant rumbles in near real-time for conservation purposes.

Climate Change in Madagascar

Madagascar is considered a global biodiversity hotspot, and as approximately 85% of its animals and 82% of its plants are endemic, it is also one of the world’s greatest conservation priorities. Unfortunately, temperatures throughout the island have been rising over the last 100 years due to unmitigated climate change, and temperatures are expected to rise by a further 3.0 °C within the next 80 years. Climate change in Madagascar has resulted in profound increases in the occurrence of droughts, cyclones, and flooding, and an understanding of how climate change will affect Madagascar’s natural habitats, plants, and animals is now urgently needed.

I am working in collaboration with several other researchers to model the effects of unmitigated future climate change on Madagascar’s flora and fauna, in an effort to see which species may be able to adapt to these changes in climate, and which species may face extinction if urgent conservation action is not taken. We recently assessed how unmitigated climate change will likely impact the distribution of four of Madagascar’s major forest types (humid, dry, spiny, and transitional forest), and if temperatures continue to rise as predicted, these important habitat types will very likely decrease in occurrence in the future. This is greatly concerning for threatened forest-dwelling animals, and the next phase of this research will seek to determine how different animal groups such as lemurs and bats are likely to respond to climate change in the future.

Effects of Forest Fragmentation on Lemurs

Over 85% of Madagascar’s original forest cover has already been cleared, of which approximately 45% is estimated to have been cleared in the last 60 years alone. There is now great concern for Madagascar’s endemic wildlife populations, of which 90% depend on forest habitat for survival. Nocturnal lemurs are particularly threatened by this wide-scale habitat loss and fragmentation because they are small-bodied, and it is therefore highly risky for them to attempt to cross the large open spaces between forest fragments. An understanding of the effects of habitat fragmentation and degradation (and its associated edge-effects) on the population dynamics and behaviour of nocturnal lemurs is urgently needed to guide effective conservation action, or their future survival has a poor prognosis.

I am studying the spatial, behavioural, and physiological responses of lemurs to habitat fragmentation and edge-effects within the Sahamalaza-Iles Radama National Park. Since 2015, I have been collecting data on lemur population densities, behavioural ecology, diet, and physiological health. I am using this data to make comparisons between 1) continuous and fragmented forest and 2) between forest core and forest edge areas, to gauge the habitat requirements of the lemurs, and to determine their behavioural flexibility and plasticity to habitat degradation. In collaboration with the local conservation NGOs Mikajy Natiora and the AEECL, the data is being used to facilitate their long-term reforestation efforts within the National Park, and to inform their species-specific lemur conservation action plans.

Vanilla Agroforestry and Biodiversity

The SAVA Region of North East Madagascar is the world’s primary vanilla-cultivation area. Throughout the region, vanilla plantations have replaced pre-existing natural forests, and the landscape is now dominated by a matrix of vanilla agroforests, anthropogenic grassland, and isolated natural forest fragments. I have worked to quantify floral and faunal species richness within the SAVA Region’s vanilla plantations using multifaceted and multi-method approaches, and to assess how this biodiversity compares between natural forest habitats and vanilla plantations under varying management regimes.

The results of this work have been highly encouraging, as vanilla agroecosystems were found to harbour many species of mammals, birds, reptiles, and amphibians. Most notably, we were able to confirm the presence of five different lemur species within the SAVA Region's vanilla plantations, and also the Critically Endangered gecko species Paroedura lohatsara. However, we found that natural forest habitat contained the greatest floral and faunal species diversity and had proportionally more threatened and endemic species than all types of plantation. Greater biodiversity can be found in minimally-managed plantations in comparison to intensively-managed plantations, and biodiversity was always higher in plantations located within close proximity to natural forests in comparison to those that were further away. These findings are highly important and encouraging for animal conservation and sustainable crop cultivation in the SAVA Region and Madagascar more-generally, and the results suggest that vanilla cultivation regimes should endeavour to follow traditional, minimalistic-management approaches to improve sustainability and promote higher species diversity.

Animal Vocal Communication

Knowledge of a species’ vocal repertoire is an essential component of the interpretation of its behaviour and sociality. For cryptic and elusive animals, vocalisations are also an important and valuable tool for species identification (particularly among sympatric species), sex/group discrimination, and non-invasive field identification, monitoring, and conservation efforts. Since 2014, I have been collaborating with several researchers to characterise and describe the loud calls and vocal repertoires of cryptic species including strepsirrhine primates, insectivorous bats, and frogs. Such descriptions enable passive acoustic detection of these species, so that they can be identified, studied, and monitored remotely in their natural forest habitats.

Behavioural Ecology of the Sambirano Mouse Lemur

The Sambirano Mouse Lemur (Microcebus sambiranensis) is a small, Endangered nocturnal primate endemic to only a few small, fragmented forests within the Sambirano Domain of North West Madagascar. Prior to my research it was completely unstudied and nothing was known of its behavioural ecology or habitat requirements, despite it being highly threatened by habitat destruction and forest fragmentation.

In my first ever research project, I investigated the ecology and vocal behaviour of M. sambiranensis in Anabohazo Forest, Sahamalaza-Iles Radama National Park, to obtain a baseline understanding of the species’ biology, from which the first conservation action plan for this species could be established. I established a radio-collared study population, followed the lemurs throughout the night to obtain data on their movements and ranging ecology, and I recorded any vocalisations that I observed. In parallel, I also located and characterised their sleeping sites during the day, and I conducted an acoustic survey of the forest to determine their habitat use. The results of this study suggest that M. sambiranensis may be somewhat resilient to habitat degradation, but its distribution may be limited by forest presence, and the availability of suitable sleeping sites.