Lessons of 15,000 Years of Human–Wildlife Interaction for Conservation in Patagonia in the 21st Century

Humans arrived in the Patagonia region of southern South America in the late Pleistocene period, ca. 15,000 years ago. A few centuries later, during a period of rapid warming, the megafauna went extinct in Patagonia, as well as some smaller species, like the guanaco (Lama guanicoe), in the southern portion of the region. As in other regions, extinctions probably occurred due to a combination of effects of climate and direct and indirect impacts of humans on wildlife communities. We reviewed recent archeological and genetic-based discoveries about numbers and distributions of humans and wildlife and their early interactions and used them to draw lessons for current debates among managers and scientists. Recent discoveries, for example, help us understand (1) the population limitation mechanisms and other interactions involving guanacos, livestock, forage, predators, and scavengers; (2) the magnitude of wildlife movements and the need for landscape-level planning for conservation; (3) the importance of indirect effects of human activities on wildlife communities; and (4) the compounded effects of human activities and climate change on wildlife. We believe these lessons drawn from deep time and recent history can help define new priorities for research and management and inform our conservation vision for the 21st century, a period when dramatic climate change impacts will add challenges to a region subject to a century of overgrazing and other anthropogenic pressures.

Ontogenetic shifts in microhabitat preference of the temperate reef fish Forsterygion lapillum: implication for population limitation

Quantitative surveys of habitat associations of New Zealand's common triplefin fish Forsterygion lapillum suggest that young settlers disproportionately occur within the fronds of the large brown algae Cystophora retroflexa and C. torulosa (hereafter collectively referred to as Cystophora). This apparent preference is specific to Cystophora (i.e. fish do not appear to respond to structurally similar macroalgal species) and is not exhibited by older juveniles or adults of the species, which suggests that age-specific microhabitat requirements may act as a bottleneck to recruitment. To determine whether the overuse of Cystophora by newly settled F. lapillum could be attributed to a behavioural preference for this specific habitat, we conducted a lab-based choice experiment. Using a purpose-built 'choice chamber' that facilitated assessments of behavioural responses of focal individuals provided with a choice of 4 common habitat types, we determined that newly settled F. lapillum selected chambers containing Cystophora more frequently than predicted by random assortment. To test the ecological consequences of this behavioural preference, we conducted a field experiment (replicated at 2 sites) that manipulated Cystophora cover and examined subsequent patterns of recruitment by F. lapillum. Experimental additions of Cystophora cover enhanced local recruitment of F. lapillum, and the effects of Cystophora additions were most pronounced at the site where Cystophora was naturally rare. Overall, these results suggest that age-specific behavioural preferences may mediate ontogenetic shifts in microhabitat use and limit recruitment in local populations. © Inter-Research 2006.

Ontogenetic shifts in microhabitat preference of the temperate reef fish Forsterygion lapillum: implication for population limitation

Quantitative surveys of habitat associations of New Zealand's common triplefin fish Forsterygion lapillum suggest that young settlers disproportionately occur within the fronds of the large brown algae Cystophora retroflexa and C. torulosa (hereafter collectively referred to as Cystophora). This apparent preference is specific to Cystophora (i.e. fish do not appear to respond to structurally similar macroalgal species) and is not exhibited by older juveniles or adults of the species, which suggests that age-specific microhabitat requirements may act as a bottleneck to recruitment. To determine whether the overuse of Cystophora by newly settled F. lapillum could be attributed to a behavioural preference for this specific habitat, we conducted a lab-based choice experiment. Using a purpose-built 'choice chamber' that facilitated assessments of behavioural responses of focal individuals provided with a choice of 4 common habitat types, we determined that newly settled F. lapillum selected chambers containing Cystophora more frequently than predicted by random assortment. To test the ecological consequences of this behavioural preference, we conducted a field experiment (replicated at 2 sites) that manipulated Cystophora cover and examined subsequent patterns of recruitment by F. lapillum. Experimental additions of Cystophora cover enhanced local recruitment of F. lapillum, and the effects of Cystophora additions were most pronounced at the site where Cystophora was naturally rare. Overall, these results suggest that age-specific behavioural preferences may mediate ontogenetic shifts in microhabitat use and limit recruitment in local populations. © Inter-Research 2006.