Critical habitat for threatened and endangered species: how should the economic costs be evaluated?

Modeling Potential Changes in Rare Species Habitat from Planned Timber Harvest in Minnesota, USA

In 2018, the Minnesota Department of Natural Resources conducted the Sustainable Timber Harvest Analysis that resulted in the 10-year Stand Exam List (SEL). The SEL includes stands that will be assessed for potential management action from 2021 to 2030, but the location, number, and impact of stands actually harvested remains unknown. This study sought to use modeling to assess potential habitat changes from the SEL for five threatened, endangered, or special concern wildlife species. Three simulation scenarios captured the potential range of harvest from the SEL, and the Wildlife Habitat Indicator for Native Genera and Species model assessed associated habitat changes. The most realistic simulation scenario resulted in statistically insignificant habitat changes of less than ±6%, while two scenarios providing the upper and lower extremes of harvest resulted in statistically significant changes for one species each. Scenarios that resulted in less harvest and more mature forests benefited the five species, reflecting their habitat preferences. The tempering of habitat change values in the most realistic simulation scenario provides evidence for forest management tradeoffs between different wildlife species habitat requirements, as well as other forest resource management objectives.

Commercial fish species of inland waters: a model for sustainability assessment and management

The permanent increase in the exploitation of commercial fish species has led to the need for developing practical and effective tools for the sustainability assessment and management of the target fish populations. The aim of this study was to formulate an ESHIPPOfishing model which would provide a reliable assessment of commercial fish population sustainability and indicate the conservation priorities. The existing ESHIPPO model was modified by introducing a new Index of local sustainability of fish populations (ILSFP) which enables the selection of "keystone populations" and "keystone habitats/ecosystems" within the basin being investigated. We employed a self-organizing map (SOM) in order to visualize the spatial distribution of the keystone populations and keystone habitats/ecosystems for each fish species. Based on the ILSFP values, environmental specialization (ES) of a fish species and local environmental factors (HIPPO factors), the model estimates the degree of sustainability (DS) of commercial fish populations in the freshwater ecosystems of the western Balkan Peninsula. The results indicate a low degree of sustainability for the majority of commercial fish species of the Middle Danube Basin, especially Acipenser ruthenus and Hucho hucho. The ESHIPPOfishing model presents a cost effective conservation approach, formulated to be applicable to any kind of river basin. The application of the ESHIPPOfishing model provides a comprehensive insight into the viability of target fish populations, which would not only further improve the selection of conservation priorities, but also facilitate the management of aquatic ecosystems.