FitzPatrick Institute of African Ornithology

Afro-Palaearctic migrants depart West Africa for breeding grounds in Europe during the transition from the dry to the wet season. Such timing can severely impact migration success because the onset of the rains varies between years, influencing food availability and migrants' body reserves, which are crucial for crossing the Sahara. We used a 23 year ringing dataset of seven migratory bird species from Nigeria to quantify changes in body mass and fat during the pre-migratory period as a function of recent and dry season rainfall and normalised difference vegetation index (NDVI). For a small subset of species, we also considered data from the wider non-breeding period. During the pre-migratory period, body reserves were positively correlated with pre-capture conditions in several species. Thus, body reserves increased after recent periods of high rainfall and NDVI, as well as with date. Effects of dry season conditions on pre-migratory body reserves were more variable, possibly linked to species-specific movement strategies in sub-Saharan Africa. During the non-breeding period, we found some support for reduced body reserves under good conditions, perhaps to enhance mobility. Limitations in fuelling due to poor recent conditions in West Africa could lead to birds departing later or in poorer condition, with potential carry-over costs to breeding.

Large shell middens or shell mounds are present throughout the world’s coastlines. They are frequent expressions of higher population densities, more sedentary lifestyles, social and technological innovation and/or complexity, and overexploitation of large and small prey. Large Holocene shell middens on the west coast of South Africa are known as megamiddens and date to the third millennium BP. Earlier studies have explained their appearance as resulting from a resource intensification process. Megamiddens situated further south in Paternoster village were known to contain comparatively larger quantities of vertebrate fauna and artifacts; however, they remained much less studied until now. Recent findings on Paternoster North megamidden, are reported here and compared to other local sites and to central west coast megamiddens. Previous observations on fauna and artifacts from Paternoster megamiddens are confirmed in this study, with their chronology appearing to be somewhat earlier than that of the central west coast megamiddens. Climatic, geographical, geological, and environmental differences in both terrestrial and coastal settings seem to explain the contrasting records. Further studies on Paternoster megamiddens will improve our understanding of a millennium which has the most intense use of coastal resources in southern African prehistory.

Seabirds can disperse widely when searching for prey, particularly during nonbreeding periods. Conservation measures predominately focus on protecting breeding colonies, while spatial protection at sea is often based on knowledge of the distribution of breeding adults, despite accumulating evidence that marine habitats used by immature birds sometimes differ from those of adults. Juvenile emperor penguins from Atka Bay, west Dronning Maud Land, Antarctica, tracked immediately after fledging performed long migrations to the northern extents of the Convention for the Conservation of Antarctic Marine Living Resources subareas 48.4 and 48.6. Individuals did not remain long at their northern positions, before commencing a rapid southerly movement to within a few hundred km of the marginal ice zone (MIZ). The initial migratory movement was broadly synchronous across individuals. The southward movement and subsequent change to area-restricted searching were consistent with the MIZ representing a potentially important feeding habitat for juvenile emperor penguins. Spatio-temporal management mechanisms may be beneficial in reducing threats to these young penguins.

Mercury (Hg) is a heterogeneously distributed toxicant affecting wildlife and human health. Yet, the spatial distribution of Hg remains poorly documented, especially in food webs, even though this knowledge is essential to assess large-scale risk of toxicity for the biota and human populations. Here, we used seabirds to assess, at an unprecedented population and geographic magnitude and high resolution, the spatial distribution of Hg in North Atlantic marine food webs. To this end, we combined tracking data of 837 seabirds from seven different species and 27 breeding colonies located across the North Atlantic and Atlantic Arctic together with Hg analyses in feathers representing individual seabird contamination based on their winter distribution. Our results highlight an east-west gradient in Hg concentrations with hot spots around southern Greenland and the east coast of Canada and a cold spot in the Barents and Kara Seas. We hypothesize that those gradients are influenced by eastern (Norwegian Atlantic Current and West Spitsbergen Current) and western (East Greenland Current) oceanic currents and melting of the Greenland Ice Sheet. By tracking spatial Hg contamination in marine ecosystems and through the identification of areas at risk of Hg toxicity, this study provides essential knowledge for international decisions about where the regulation of pollutants should be prioritized.

Abstract In many countries, catchment restoration is underfunded. This study aims to address whether household water pricing could be used as a mechanism for securing funds for catchment restoration. The objectives were to determine households' willingness to pay (WTP) for their existing water use, investigate whether institutional trust and municipal satisfaction influenced WTP, and establish whether aggregate consumer surplus at the municipal scale could cover the costs needed to finance catchment restoration. Surveys were conducted on 502 households in three metropolitan municipalities in the City of Cape Town, eThekwini, and Nelson Mandela Bay. Contingent valuation revealed that average WTP for water was between 12 and 137% more and 32 and 73% more than what households currently pay for water per month in the City of Cape Town and eThekwini, respectively. Satisfaction with municipal service delivery positively influenced WTP, while institutional trust did not. The City of Cape Town, based on the aggregate WTP from the higher income categories, consumer surplus was 779 million South African Rand (ZAR)/year, more than double the estimated cost required to restore the catchment areas supplying water to the city over 30 years. In eThekwini, consumer surplus was equal to the amount needed over 30 years (250 million ZAR/year). These results demonstrate the significant potential to raise water tariffs for higher income households in metropolitan municipalities.

The large, iconic nests constructed by social species are engineered to create internal conditions buffered from external climatic extremes, to allow reproduction and/or food production. Nest-inhabiting eusocial Macrotermitinae (Blattodea: Isoptera) are outstanding palaeo-tropical ecosystem engineers that evolved fungus-growing to break down plant matter ca 62 Mya; the termites feed on the fungus and plant matter. Fungus-growing ensures a constant food supply, but the fungi need temperature-buffered, high humidity conditions, created in architecturally complex, often tall, nest-structures (mounds). Given the need for constant and similar internal nest conditions by fungi farmed by different Macrotermes species, we assessed whether current distributions of six African Macrotermes correlate with similar variables, and whether this would reflect in expected species' distribution shifts with climate change. The primary variables explaining species’ distributions were not the same for the different species. Distributionally, three of the six species are predicted to see declines in highly suitable climate. For two species, range increases should be small (less than 9%), and for a single species, M. vitrialatus, ‘very suitable’ climate could increase by 64%. Mismatches in vegetation requirements and anthropogenic habitat transformation may preclude range expansion, however, presaging disruption to ecosystem patterns and processes that will cascade through systems at both landscape and continental scales.This article is part of the theme issue ‘The evolutionary ecology of nests: a cross-taxon approach’.

Combined effects of multiple, climate change-associated stressors are of mounting concern, especially in Arctic ecosystems. Elevated mercury (Hg) exposure in Arctic animals could affect behavioral responses to changes in foraging landscapes caused by climate change, generating interactive effects on behavior and population resilience. We investigated this hypothesis in little auks (Alle alle), a keystone Arctic seabird. We compiled behavioral data for 44 birds across 5 years using accelerometers while also quantifying blood Hg and environmental conditions. Warm sea surface temperature (SST) and low sea ice coverage reshaped time activity budgets (TABs) and diving patterns, causing decreased resting, increased flight, and longer dives. Mercury contamination was not associated with TABs. However, highly contaminated birds lengthened interdive breaks when making long dives, suggesting Hg-induced physiological limitations. As dive durations increased with warm SST, subtle toxicological effects threaten to increasingly constrain diving and foraging efficiency as climate change progresses, with ecosystem-wide repercussions.

Abstract Woody‐plant encroachment is an under‐recognized consequence of land degradation. This phenomenon is common in rangeland ecosystems, where woody plants outcompete grasses, resulting in a shift to more wooded ecosystems. The consequences of this for livelihoods are most often damaging. Case studies at a local scale have shown negative consequences for ecosystem services and livelihoods, though few have considered these impacts over greater scales to find more generalizable patterns that are useful for governance structures at actionable levels. Here we make use of census data on household income and use of provisioning ecosystem services together with remote‐sensed woody‐plant encroachment data to perform the first country‐wide assessment at the municipal level across South Africa investigating correlations between woody cover change and (1) household income and (2) the use of provisioning ecosystem services use. We show that woody‐plant encroachment is greatest in municipalities with low income and a higher reliance on provisioning ecosystem services, specifically when woody cover was low. This reinforces a poverty trap by creating a positive‐feedback loop. For example, encroached landscapes with lower grass cover are more prone to overgrazing, decreasing fuel loads and further driving encroachment. This places more pressure on the remaining grass cover and decreases the provisioning of ecosystem services. Furthermore, our results allow us to rank the most affected municipalities based on income, reliance on provisioning ecosystem services and rates of woody cover change. We identify 16 municipalities requiring much‐needed interventions due to the risk of woody‐plant encroachment to natural resource‐reliant livelihoods. We suggest that interventions to reduce woody‐plant encroachment be targeted in low‐income communities, providing a win–win scenario for livelihoods and biodiversity. We recommend that woody‐plant encroachment be recognized as major form of land degradation and that restoration of encroached landscapes be prioritized within the UN Decade of Ecological Restoration 2021–2030. Read the free Plain Language Summary for this article on the Journal blog.

To support and scale up global restoration efforts, the United Nations (UN) has proclaimed 2021–2030 the “UN Decade on Ecosystem Restoration.” The Decade offers significant opportunities for and challenges to restoration, in particular for Africa, a continent that has a large need and potential for restoration. We thus argue that the Decade must be a success in and for Africa, and for this to happen, opportunities and challenges to achieving its goals must be promptly identified, and considered in the planning and implementation of restoration. Here, we outline six key areas that should be considered at a strategic level by African countries during the Decade. These are: (1) ensuring effective oversight and governance relevant to Africa; (2) translating the goals to meet the African context; (3) making the case for restoration amid multiple development demands; (4) growing an African restoration community of practice based on regional need; (5) collaborating to improve restoration outcomes; and (6) establishing an Africa‐relevant evidence base for restoration. We believe that these six key areas—even though they are not all novel—are currently not addressed at a level that matches the scale of the problem on the continent. Although the specific actions to be taken under each key area are dependent on the restoration context, integrating these key areas in the planning and implementation of restoration efforts will likely lead to improved restoration outcomes during the Decade.