Renal physiology of two southern African Mastomys species (Rodentia: Muridae): a salt-loading experiment to assess concentrating ability

Aspects of renal physiology were examined to test the hypothesis that two cryptic species of the genus Mastomys (Mastomys natalensis and Mastomys coucha) are geographically separated by differences in aridity tolerance. Laboratory-bred females of each species were subjected to different levels of salinity in their water source (distilled water, 0.9% NaCl, and 1.5% NaCl; 10 conspecifics in each group) from weaning until sexual maturity. Individuals of the two species exhibited similar rates of water consumption and urine production. The salinity treatments caused sodium diuresis in both species, evident in increased urine volume, decreased osmolality and increased osmotic output. Urine concentration, kidney mass and kidney relative medullary area (RMA) did not differ between species. The results of our study do not support the hypothesis that differences in osmoregulatory ability separate these two cryptic species. Nor do they support the use of salt loading to elicit maximum urine concentrations in mammals.     

No Evidence‐Based Restoration Without a Sound Evidence Base: A Reply to Guldemond et al.

Evidence‐based practice is not possible without an evidence base. Guldemond et al. confuse our attempt at assessing the status of the evidence base of restoration programs in South Africa with attempting to assess whether restoration is evidence‐based. While we fully agree with them that there is a need to assess whether practitioners use evidence in their decision‐making, we assert that use of evidence is the last step in the evidence‐based approach. It is preceded by the generation (and documentation) of evidence through baseline condition assessment, proper goal setting, sound monitoring of the impacts of the chosen intervention as well as effective dissemination of resulting evidence. To answer the question whether restoration is evidence‐based would require the assessment of all stages from generation to use. We chose to start at the beginning, a logical place to start.     

Assessing the Evidence Base for Restoration in South Africa

If restoration is to become effective, able to compete for limited funds and truly adaptive, it must become evidence‐based. Three of the conditions essential for the establishment and advancement of evidence‐based restoration are (1) collection of baseline information; (2) setting clearly defined goals; and (3) relevant and adequate monitoring. Using a literature review, complemented with an online survey, we reviewed 10 restoration programs in South Africa to assess whether current restoration practice meets these conditions. The review showed good collection of baseline information and the setting of restoration goals that span ecological and socioeconomic considerations. However, to a large extent goals were poorly defined, there was more monitoring of inputs than outcomes, and monitoring of ecological indicators was inconsistent. These shortcomings can undermine restoration impacts, as well as the future sustainability of these expensive programs. We conclude with recommendations on how to mainstream the requirements of evidence‐based restoration into current and proposed restoration programs.