The movement behaviour of largemouth bass Micropterus salmoides in the estuarine headwater region of the Kowie River, South Africa, was investigated using passive acoustic telemetry. Ten adult fish were tagged and released in four discrete pools below a weir that precluded possible upriver migration. Their residency and movement patterns were monitored using 27 moored acoustic receivers spanning both riverine and estuarine habitats between January and November 2013. Small-scale movements ranging from 50 to 400 m occurred between pools in the headwater region, where tagged fish remained resident (did not leave their tagging pool) during the warmer (summer) months. The onset of autumn and winter correlated with declining water temperatures and half of the tagged largemouth bass made downstream excursions into the slightly warmer upper reaches of the estuary. The penetration of these alien piscivores into estuarine headwaters potentially provide additional predator pressure on the juveniles of migratory estuary-associated native marine fish species, which utilise these areas as nurseries. The presence of the alien fish in South African estuarine headwaters may impair the migration of juvenile fishes between the estuarine and freshwater environments.

The trophic relationships of two hake species (Merluccius capensis and M. paradoxus) and three shark species (Centrophorus squamosus, Deania calcea and D. profundorum) were investigated using nitrogen and carbon stable isotope signatures (δ¹⁵N and δ¹³C) of their muscle tissues. The sharks were more enriched in ¹⁵N than the hake, an indication of the apex predator status of sharks. Among the sharks considered, C. squamosus occupied the highest trophic level and fed primarily on benthic prey. The two species of shark from the genus Deania were not different based on δ¹⁵N or δ¹³C, so they had similar diets. The δ¹³C signatures indicated that M. capensis and sharks fed on prey derived from similar basal resources. However, there was a significant difference in δ¹³C between M. paradoxus and all other species examined, suggesting that they occupied different feeding niches. Isotope-based population metrics showed narrower trophic ranges in sharks than M. capensis. Carbon and nitrogen ranges indicated that hake fed on a more diverse pool of carbon sources and had generally more enhanced trophic diversity in their feeding patterns than sharks. Among the species considered, C. squamosus occupied a unique isotopic space. Our results supported the hypothesis there are trophic overlaps among these species, but some interesting differentiation was revealed.

Fire is widely used as a management strategy in grasslands to maintain vegetation structure and improve grazing quality for large herbivores. The impacts of burning on invertebrates in South Africa remain poorly understood. A study was initiated in spring 2005 to determine the impact of a fast hot burn on ground-dwelling spider assemblages in a grassland habitat in the central Free State. Pitfall traps were set out at six sites in the reserve, with three sites each in the burnt and unburnt areas, to sample spiders over a 12-month period. A total of 5 253 spiders were collected, representing 33 families and 120 species. Spider abundance was significantly lower in the burnt (n = 1 956) than unburnt sites (n = 3 297), and burnt sites had, on average, considerably fewer species than unburnt sites. The dominant families in the burnt sites were Lycosidae (29.5%), Gnaphosidae (16.9%), Ammoxenidae (9.6%) and Zodariidae (5.7%), whereas Ammoxenidae (22.7%), Lycosidae (20.6%), Gnaphosidae (15.3%) and Amaurobiidae (10.2%) dominated the unburnt sites. Of the nine most abundant families collected, only Caponiidae were more abundant in the burnt than unburnt sites. Our data suggest that fast-burning hot spring fires cause a considerable initial post-fire decline in spider abundance, and have a negative influence on the abundance as well as the resistance of assemblages to disturbances other than fire (e.g. rain). However, most of the dominant families had abundances comparable to unburnt areas within a year post-burn.

Many highly invasive plant species produce fleshy fruit that are consumed and dispersed by frugivorous birds. However, little is known about assimilation efficiency of invasive fruit by indigenous and invasive avian species. We investigated whether indigenous Knysna (Tauraco corythaix) and Purple-crested (Gallirex porphyreolophus) Turacos and invasive alien Rose-ringed Parakeets (Psittacula krameri) met their energy demands when fed fruits of four fleshy fruited invasive alien plant species: Solanum mauritianum, Cinnamomum camphora, Psidium guajava and Morus alba. Birds were fed single-fruit diets for two consecutive days and energetic parameters were calculated for all fruit diets. Our results showed that generally both invasive and indigenous avian species managed to gain their daily energy requirements from fruits of the four respective invasive plants, suggesting that they can meet their energetic demands by feeding on them only. The exception was P. krameri, which did not feed on S. mauritianum fruit. These findings may explain why fruits of invasive alien plants are attractive to most avian frugivores and highlight the role of avian frugivores in their dispersal.

The status of waterbirds breeding in protected areas in North Africa needs constant monitoring because of a naturally fluctuating environment and permissive attitudes towards illegal activities likely to negatively affect population dynamics of threatened species. We present the results of a study conducted at a protected site, Lake Tonga, north-eastern Algeria, on a breeding population of Ferruginous Duck Aythya nyroca, a Near-Threatened duck subjected to considerable pressure from egg-pilfering and illegal hunting. Two distinct habitats within the lake were used by Ferruginous Duck: an Alder carr (Alnus glutinosa) and floating islets across the lake. The mean clutch size was 9.51 ± 1.84 eggs (N = 51 clutches) with hatching rate of 80.7% for successful clutches. Breeding success was low (37%) with predation (33%) and clutch desertion (17%) accounting for the majority of failed nests. The probabilities of nest failure and nest desertion increased with a delayed onset of egg laying. Predation was not significantly associated with egg laying date and vegetation cover, but late breeders nesting in dense vegetation seemed to suffer less predation. Conspecific brood parasitism was positively associated with nest size, whereas interspecific brood parasitism was marginally associated with water depth. We discuss different hypotheses concerning nest desertion, and argue that illegal hunting and disturbance may best explain why birds desert their nests.

It has long been presumed that waterbirds disperse the propagules of aquatic organisms. However, it is only in recent years that this claim has been empirically explored and little is still known about waterbird-mediated dispersal in southern Africa. Aquatic invertebrates are thought to be well adapted to dispersal by waterbirds because of their ability to produce hardy resting eggs. We explored the capacity of waterbirds to disperse the eggs of both cladocera and bryozoans via endo- and ectozoochory. We examined 283 faecal samples and 394 feather brushings from six waterbird species and two wetland sites in South Africa for the presence of diapausing eggs. A total of 108 intact diaspores were recovered, with intact eggs present in 16% and 7% of the faecal samples and feather brushings, respectively. Our results indicate that southern African waterbirds do take up the resting eggs of aquatic invertebrates and that these eggs can survive intact through the gut or remain attached to the feathers. These results provide evidence that waterbirds may be important vectors for aquatic invertebrates in southern Africa and imply that waterbirds may play a vital role in maintaining connectivity between invertebrate populations in isolated wetland patches.

Transfers to new breeding herds and supplementary feeding are crucial management steps for small populations of ungulates. However, the successful realisation of those steps is strongly dependent on social interactions among individuals. Agonistic encounters connected with feeding determine the quality and quantity of the food accessed, and therefore directly influence food intake. We analysed the dominance relationships of mixed herds of critically endangered Western Derby eland with regard to access to supplementary food in the Bandia reserve, Senegal. We tested the influence of age and sex on feeding rank, the linearity and stability of hierarchies and the relationship between the position of an offspring in the hierarchy and the position of its mother. A linear hierarchy existed in all herds. Sex influenced the rank only in interaction with age. Feeding rank was significantly related to age in growing animals; in adults the effect of age was weaker. While body mass is correlated with age during the growth period and not after reaching adulthood, we concluded that the position in the hierarchy was related to the actual condition, reflecting the resource holding potential of individuals. The dominance index of a growing offspring depended on the index of its mother, but hierarchies of adult individuals were not stable. High-ranking individuals in good condition limited access to supplementary feeding to their lower-ranking herdmates. Effective supplementary feeding should therefore be provided in excess amounts to enable younger and weaker individuals in need to benefit from it, despite their lower positions in the hierarchy.

To better understand how Cape porcupines are able to successfully occupy many agricultural lands, we studied their digestive parameters and energy assimilation when fed three economically important agricultural crops (potatoes [Solanum tuberosum], sweet potatoes [Ipomoea batatas] and butternut [Juglans cinerea]). Daily food intake, daily gross energy intake, daily faecal energy loss, daily energy assimilated, daily water intake and apparent assimilation efficiency were calculated for each porcupine and for each diet trial. Cape porcupines maintained body mass on all three experimental diets and energy intake ranged from 3 002.36 kJ kg^-1 d^-1 (potato) to 4 499.00 kJ kg^-1 d^-1 (sweet potato). The moisture content in each experimental diet was relatively high (>60%) and preformed water intake of winter acclimated Cape porcupines ranged from 60 ml kg^-1 d^-1 (potato) to 100 ml kg^-1 d^-1 (sweet potato). Assimilation efficiencies were high (>85%) on all three diets. Cape porcupines ingested c. 1.5–2.7 kg of each crop daily, translating to potentially large economic impacts on farmers. Knowledge and understanding of Cape porcupine food intake and dietary requirements give insight to their potential impact on commercial crops. This may aid in developing management and conservation strategies needed to manage this human—wildlife conflict.

Despite its cryptic habitat and habits, light and transmission electron microscopy has revealed that like many other siphonariids Siphonaria compressa, the smallest species of this genus, possesses lateral pedal glands. The pear-shaped glands (about 120 µm long × 70 µm maximum diameter) open via a pore, and are multicellular with three types of secretory cell that surround a central lumen. The glands of this minute pulmonate limpet are similar in structure to its larger relatives, suggesting that they are defensive in function.

Lactation boosts reproductive costs by depleting maternal condition and delaying subsequent conception. However, some evidence suggests that giraffes (Giraffa camelopardalis) have evolved a mechanism to minimise the time allocated to suckling-induced suppression of ovulation. Here, we show for the first time that wild giraffe cows are impregnated while nursing a young calf. We suggest that a trio of traits (non-seasonal breeding, slow embryonic development and rapid calf growth) have promoted this unusual and flexible female reproductive strategy.