EBM5: Species specific conservation actions in the time of ecosystem-based management

Date: Thursday October 11, 2018

Location: Tieva, Lappia Hall

Time: 10:30-12:00

At the same time as ecosystem-based management, together with ecosystem-based monitoring, are advocated by CAFF and others, many ongoing conservation programs focus on specific threatened species, whereas other management actions focus on overabundant or increasing species. Even within CAFF, working groups are often assembled around a certain species or a taxonomically defined species group. It may be easier to obtain financial or political support, and gather experts around the challenges of specific species. A species-specific approach can however evolve into ecosystem-based initiatives. In this session, we will use the case of the conservation of the critically endangered arctic fox in Fennoscandia as a start point to discuss how a species focused conservation effort can evolve into ecosystem-based monitoring and management. The aim of the session is to shed light on the dichotomy and possible synergies between species-focused and ecosystem-based approaches in management in the Arctic in general. The format of the session will be a series of presentations followed by a discussion with all participants.

Chairs: Dorothee Ehrich, UiT - The Arctic University of Norway; Nina Elisabeth Eide, Norwegian Institute for Nature Research

Format: Series of presentations followed by discussion

Presentations:

1. Ecosystem drivers and adaptive management of the critically endangered arctic fox in northeastern Norway: Dorothee Ehrich, UiT - The Arctic University of Norway 
2. Status and conservation goals for the critically endangered Arctic fox in Scandinavia. When is mission completed? Nina Elisabeth Eide, Norwegian Institute for Nature Research 
3. The fluctuating world of a tundra predator guild: Bottom-up constraints overrule top-down species interactions in winter: Marianne Stoessel, Stockholm University  
4. Opposite predation-mediated effects of food web dynamicson an endangered arctic-nesting goose species: implications for management: Filippo Marolla, UiT - The Arctic University of Norway 
5. Large scale Arctic raptors monitoring as an alternative to the ecosystem based approach: Olga Kulikova, Scientific center for Arctic research of the Yamal-Nenets Autonomous District, Russia; Nadia French, PRPI/University of Birmingham  

Abstracts:

Ecosystem drivers and adaptive management of the critically endangered arctic fox in northeastern Norway

Dorothee Ehrich, UiT - The Arctic University of Norway; Siw T. Killengreen, UiT - The Arctic University of Norway; Rolf A. Ims, UiT - The Arctic University of Norway

The arctic fox is critically endangered in Fennoscandia due to overharvesting in the beginning of the last century and ongoing tundra ecosystem changes. As part of the Norwegian Environment Agency’s arctic fox conservation program, the project “Arctic fox in Finnmark” was initiated in 2004 to document the state of the arctic fox in eastern Finnmark, in the very North East of Norway, and investigate needs for conservation. Since the start of the project, important aims were also to study the structure and the dynamics of ecosystem components likely to affect the arctic fox, and to assess experimentally whether culling of red foxes as a management action would release arctic foxes from this stronger competitor, and would allow the population to recover. From the beginning, this species focused conservation project applied thus an ecosystem-based approach to monitoring and management. A synthesis of the results from the projects first 11 years identified two fundamental drivers for the lack of recovery and further decline of the Arctic fox: 1) An increasing irregularity of lemming cycles likely driven by a changing winter climate and 2) an increasing abundance of red foxes, which are subsidized by carrion of semi-domestic reindeer. Because of the important role of the red fox in limiting the recovery of arctic foxes, the ecosystem perspective of the project was enlarged with more investigations of the drivers of this expanding generalist predator population. Results showed that the fluctuating lemming populations likely attract waves of immigrants, which contribute to periodic population increase, while carrion of semi-domestic reindeer and possibly other anthropogenic subsidies allow red foxes to survive winters when small rodents are scarce.

Status and conservation goals for the critically endangered Arctic fox in Scandinavia. When is mission completed? 

Nina Elisabeth Eide, Norwegian Institute for Nature Research

Anders Angerbjörn (2) Stefan Blumenthrat (1), Arild Landa (1), Bodil Elmhagen (2), Karin Noren (2), Heikki Henttonen (3), Tuomo Ollila (4), Øystein Flagstad (1)

1) Norwegian Institute for Nature Research, Norway

2) Department of Zoology, Stockholm University, Sweden

3) Finnish Forest Research Institute, Finland

4) Metsahallitus-Finnish Park and Forest Service, Finland

The arctic fox is listed as critically endangered, despite 80 years of protection in Scandinavia. Following intensive action programs over the last 15 years, systematic monitoring of the subpopulations in all three countries has revealed that the total population has increased from less than 50 to more than 250 reproductive individuals. Sub-populations are re-established, and the connectivity is about to be restored. Actions comprised red fox culling, supplemental feeding and release of captive breed Arctic foxes. Long lasting conservation programs need goals, to be targeted and effective, to keep priority for funding within environmental agencies, as well as legitimacy in the society. Although the Scandinavian arctic fox population has increased, the population is still far from being viable. We have calculated the potential carrying capacity of different subpopulations based on landscape productivity and the Nature Index methodology. Restoring populations is by fare most effective through release of captive breed foxes. Subpopulations with released cubs, also have the highest growth rate compared to subpopulations that achieved supplemental feeding and/or red fox culling. But it is also the most intensive and costly conservation measure, that need to be effectively used. In this study we use distance from carrying capacity and connectivity/degree of isolation, to target the need for actions and define conservation goals at the level of sub-populations. To achieve a viable population of Arctic foxes in Scandinavia, intensive actions will likely be needed 15-20 years more. Up to now the conservation efforts has been very species orientated. We urge the need for more ecosystem-based management, that would also expedite the success of the conservation efforts. 

The fluctuating world of a tundra predator guild: Bottom-up constraints overrule top-down species interactions in winter

Marianne Stoessel, Stockholm University; Bodil Elmhagen; tockholm University; Anders Angerbjörn Stockholm University

Global warming is predicted to change ecosystem functioning and structure in Arctic ecosystems by strengthening top-down species interactions, i.e. predation pressure on small herbivores and interference between predators. Yet, previous research is biased towards the summer season. Due to greater abiotic constraints, Arctic ecosystem characteristics might be more pronounced in winter. Here we test the hypothesis that top-down species interactions prevail over bottom-up effects in southern alpine tundra where effects of climate warming have been observed and top-down interactions are expected to strengthen. But we test this a-priori hypothesis in winter and throughout the 3-4 year rodent cycle, which imposes additional pulsed resource constraints. We used snowtracking data recorded in 12 winters (2004-2015) to analyse the spatial patterns of a tundra predator guild (arctic fox Vulpes lagopus, red fox Vulpes vulpes, wolverine Gulo gulo) and small prey (ptarmigan, Lagopus spp). The a-priori top-down hypothesis was then tested through structural equation modelling, for each phase of the rodent cycle. There was weak support for this hypothesis, with top-down effects only discerned on arctic fox (weakly, by wolverine) and ptarmigan (by arctic fox) at intermediate and high rodent availability respectively. Overall, bottom-up constraints appeared more influential on the winter community structure. Cold specialist predators (arctic fox and wolverine) showed variable landscape associations, while the boreal predator (red fox) appeared strongly dependent on productive habitats and ptarmigan abundance. Thus, we suggest that the unpredictability of food resources determines the winter ecology of the cold specialist predators, while the boreal predator relies on resource rich habitats. The constraints imposed by winters and temporary resource lows should therefore counteract productivity-driven ecosystem change and have a stabilizing effect on community structure. Hence, the interplay between summer and winter conditions should determine the rate of Arctic ecosystem change in the context of global warming.

Opposite predation-mediated effects of food web dynamicson an endangered arctic-nesting goose species: implications for management

Filippo Marolla, Tomas Aarvak, Ingar J. Øien, Jarad P. Mellard, John-André Henden, Sandra Hamel, Audun Stien, TorkildTveraa, Nigel G. Yoccoz, Rolf A. Ims

In the view of ecosystem-based management, it is fundamental to disentangle and quantify species interactions, in order to implement effective management strategies. The Fennoscandian population of Lesser White-fronted Goose (LWFG) Anser erythropus has been subject to several conservation initiatives to prevent it from extinction, including red fox culling to lower predation and increase reproductive success. We evaluated whether this action had the expected positive effect, while taking into account ecological factors that may drive variation in predation pressure and thus confound the effect of the action. We used a 19-years time series on LWFG demography that included 10 years before and 9 years after the onset of the fox culling, and matched the data with simultaneous time series of small rodent population density and amount of reindeer carrion. As expected, we found that LWFG breeding success fluctuates synchronously with the rodent cycle, suggesting an apparent facilitation mechanism. Moreover, we found a negative effect of reindeer carrion abundance, which are likely to enhance fox survival during the harsh Arctic winter. However, there was no evidence in the data for a positive effect of fox culling. This study emphasize the importance of scientifically evaluating the effectiveness of management actions.

Large scale Arctic raptors monitoring as an alternative to the ecosystem based approach

Olga Kulikova, Scientific center for Arctic research of the Yamal-Nenets autonomous district, Russia; Nadia French, PRPI/Birmingham University

Fifteen years have passed since the Arctic Council adopted the ecosystem approach (EA) as a key principle of management in the Arctic, though to date very few methods were developed to implement it, especially on land. While EA is imbedded in the scientific knowledge about the ecosystem, there is a clear mismatch between generated and meaningful or scalable knowledge within this framework. Moreover, while the Arctic Council has predominantly focused on the marine environment, terrestrial ecosystems are hardly less threatened, better understood or managed. To date, there have been few projects which can be called ecosystem-based in the Arctic, that is comprehensively observing Arctic biotic-abiotic interactions over a prolonged period of time, and that is mainly due to high costs and amount of resources required. Having looked at the alternative methods used on land, we came to focus on a particular species interaction with its environment as a proxy for a more inclusive framework with lesser effort compared to full-on EA. In particular, we looked at raptors, specifically the rough-legged buzzard Buteo lagopus. This bird species has circumpolar distribution and is usually abundant across all tundra biomes, except High-Arctic barrens. According to a 10-year research of its diet and movement in the western part of the Russian Arctic (Pokrovskiy&Kulikova), its trophic connection to lemmings was highly exaggerated in literature and despite the expectations the large scale collapse of lemming cycles in the western Palearctic during the last decades have not led to disappearance of buzzards along the vast part of the distribution area. This predator manages to substitute the absence of such an easy and highly abundant prey as lemmings with various other species – voles, ptarmigans, snow hares and even geese (Pokrovskiy et.al 2013), therefore showing strong connection with most of the tundra herbivore groups. In addition, during its spring migration it is not likely to change its’ breeding ground unless it is absolutely unsuitable for raising young. Based on these facts we argue that absence or deep density decline of rough-legged buzzards across vast area for a long period of time can indicate ecosystem scale problems. As we explored the untapped potential of this species for further research as well as management of Arctic terrestrial ecosystems, we found that scaling up the monitoring network for Arctic raptors may help build towards realistic ecosystem-based methodology in the Arctic science and governance.