Management factors affecting densities of common grassland birds of high elevation grasslands of eastern South Africa:Ingula as a case study

Background: World?wide grassland birds are in decline due to habitat loss and degradation resulting from inten?sive agricultural practices. Understanding how key grassland habitat attributes determine grassland bird densities is required to make appropriate conservation decisions. We examine drivers of bird densities in a South African grass?land area that has been managed for biodiversity conservation with reduced grazing pressure.Methods: We estimated the density of the eight most common grassland bird species encountered in our area to evaluate the effects of recent grassland management changes on the avifauna. We collected data on birds and habitat from the austral summers of 2006/2007, 2007/2008 and 2010/2011. We used hierarchical distance sampling methods to estimate density of birds relative to two main habitat variables, i.e., grass cover and height. In addition, we used regression splines within these distance sampling models as a more flexible description of suitable ranges of grass height and cover for each species.Results: For most species, density is related to grass height and cover as expected. The African Quailfinch(Ortygospiza atricollis) and Common Quail(Coturnix coturnix) preferred relatively short and open grass. The Yellow?breasted Pipit(Anthus chloris), African Pipit(Anthus cinnamomeus) and Red?capped Lark(Calandrella cinerea) preferred short and relatively dense grass, while the Wing?snapping Cisticola(Cisticola ayresii) preferred grass of intermediate height and cover. The Cape Longclaw(Macronyx capensis) and Zitting Cisticola(Cisticola juncidis) preferred tall and dense grass. Our results agree with previous studies that grass height combined with grass cover are the most important habitat features that managers should manipulate in order to increase the density of target species. The regression splines show that the effect of these two habitat variables on density is well described by linear relationships for most species.Conclusions: This study supports previous studies suggesting that grazing and fire are important tools for manage?ment to use in order to create a mosaic of grass height and cover that would support high densities of desired spe?cies. We suggest that conservation managers of these grasslands combine fire and grazing as management tools to create suitable habitats for grassland birds in general.

Rostrum abnormalities in the endangered Indian Ocean humpback dolphin(Sousa plumbea)in South Africa

Morphological abnormalities in wild animals can be indicators of the underlying health of a population and may be determined through routine photographic surveys.Here,we assess unusual rostrum conditions in Indian Ocean humpback dolphins(Sousa plumbea)inhabiting South African coastal waters to understand the rate of prevalence of abnormal rostrums and formulate hypotheses on potential causes.Photographic data were collated from sys-tematic boat surveys and opportunistic sightings,obtained between April 1998 and March 2021 in various regions along the South African coast.Overall,31 unique individuals were found with abnormal rostrum conditions,vary-ing from slight misalignments to severe wounds and/or aberrant morphologies.In most cases,injuries were likely caused by natural events during the animal’s life history such as interactions with sharks and/or reef-associated hunting strategies.Mark–recapture data indicated that individuals had survived with these injuries for up to 10 years.This study reports the highest incidence of rostrum abnormalities in the species.As numbers reflect only those that have survived their injuries,they are considered a minimum estimate.A better understanding of the cause(s)of these injuries is important given the endangered status of this species.