Patterns of red tree vole distribution and habitat suitability: implications for surveys and conservation planning

Abstract

Abstract. Environmental regulations often require wildlife surveys prior to habitat disturbance to avoid impacts or as the basis for planning mitigation, yet project-level surveys may not provide the insights needed to guide long-term management. Management of the red tree vole (Arborimus longicaudus) has largely been based on such surveys. As an alternative approach, we evaluated distribution patterns using frequency of red tree vole occurrence and habitat suitability models to guide conservation planning. We developed a suite of models based on subsets of covariates from two previously developed models and evaluated the extent to which spatial covariates improved the models. We used presence-absence data that were collected from 364 randomly selected 1-ha Current Vegetation Survey and Forest Inventory and Analysis plots to develop models and describe occurrence patterns. The best models included a spatial covariate, maximum tree diameter, distance from suitable habitat, forest age class, and the interaction between maximum tree diameter and forest age class. We compared performance of the previously published models, our best model, and an ensemble model that used predictions from all three models. Under the ensemble model, correct classification rates were relatively high and considerably improved, suggesting that the application of all three models provided greater accuracy than any individual model. We argue that habitat models, coupled with spatial patterns of the frequency of occurrence, can provide useful tools for addressing species management and may provide more insight than project-level surveys. The use of habitat suitability models can therefore be closely tied to red tree vole management decisions and conservation strategies, as well as reducing survey costs that otherwise often make projects infeasible.

Sampling strategies for species with high breeding-site fidelity: A case study in burrow-nesting seabirds

“…If spatial patterns of distribution are known a priori , this information can be used to obtain more accurate estimates by stratifying sampling approaches. In ecology, stratification is typically carried out using strata across geographical space, most often defined by distinct habitat types [16,17], and abundance estimates for each strata are then combined to give an overall estimate for the area. This approach has been successful in census and monitoring efforts across many taxa [18,19].…”

Ecosystem Conditions That Influence the Viability of an Old-Forest Species with Limited Vagility: The Red Tree Vole

“…The watershed index (WI) model ( Figure 3 ) provided an index of the capability of a watershed to contribute to the viability of red tree voles [ 21 , 24 ]. Our selection of variables to include in the WI model was based on an extensive review of the literature, e.g., [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 16 , 17 , 19 , 33 , 34 , 35 , 36 , 37 , 38 ] and the expert review of our selections. The WI model outcome was estimated from spatial measures of habitat quality and risk factors ( Figure 3 ).…”