Forests contain roughly 90% of terrestrial biodiversity and they provide a wide variety of ecosystem services, contributing to the livelihoods of more than 1 billion people [1]. Yet, forest degradation and deforestation are advancing at alarming rate, especially in the tropics [2] and are putting at risk a high diversity of species and habitats sustained by forest ecosystems [3].

Establishment of in situ conservation strategies, such as protected areas (PAs), has been the major response to a global demand for conservation of biodiversity and ecosystem services [4] and more specifically, to the reduction of tropical deforestation [5]. Accordingly, there has been a year-on-year increase in the number of PAs and they are today covering more than 12% of the total world’s land surface [6] and 13.5% of the world’s forests [3].

Nevertheless, the effectiveness of biodiversity and forest conservation measures^a is under question as the rate of biodiversity loss is not decelerating [7]. There is evidence that PAs are decreasing the deforestation rate [5, 8], estimated through measures of land clearing prevention [9] and decreasing the incidence of forest fires [10]. However, some authors argue that many of the claimed positive conservation effects might be a function of a PA location i.e. low accessibility of protected land, but not the effect of actual protection measures [5, 11]. Additionally, increasing deforestation and pressures on the resources in social-ecological systems that surround PAs, might diminish conservation efforts inside PAs, through effects of ecological isolation and landscape fragmentation [8, 12].

However, there is no systematic information on how different local governance modes and day-to-day decision-making processes within forest PAs may cause a change in PA effectiveness in terms of producing desired conservation outcomes. In context of PAs, governance can be defined as “a set of processes, procedures, resources, institutions and actors that determine how decisions are made and implemented” ([13]:105). It is about power, relationships, accountability and responsibility exercised by organisations and actors [14, 15]. Conservation governance arrangements are becoming multilevel and complex [16]. Governments are not the only source of environmental decision-making authority and there is a shift from administrative to collaborative state [17]. Power to make and enforce decisions is distributed among diverse social actors [18], including indigenous, mobile and local communities, local governments, NGOs and the private sector [19]. The change of the scale of governance has been occurring (mostly in the developing countries), and the authority and responsibility to make and enforce decisions are shifted from nation-state to lower-level authorities (decentralization) or to institutions outside the state (devolution) [20, 21].

Fifth, hybrid governance type may be added to this classification as in the reality borders between governance modes are blurred [30] and this is especially because of complex land and resource ownership rights, diversity in management authority and funding sources [31].

Nevertheless, the importance of the local political processes within PAs is frequently ignored in the conservation effectiveness literature. Therefore, to improve PAs governance and their conservation outcomes, there is need for more clear information on how differences in local governance modes and decision-making processes may cause variability in the outcomes and thus, in the effectiveness of forest PAs.

Four previous Systematic Reviews have addressed the various aspects of community-based conservation, synthesising and assessing primary literature on: 1) development as a conservation tool [32]; 2) the effect of local cultural context [33] and 3) broader social - political context on community based management [34], and 4) community forest management as a mechanism for supplying global environmental benefits and improving local welfare [35]. There are two more Systematic Reviews that have a wider conservation focus on terrestrial PAs and their 1) effectiveness in maintaining biodiversity and reducing habitat loss [36] and 2) securing human-well being (in preparation) [37]. This Systematic review is complementary to previous ones, looking from the governance perspective on effectiveness of forest protected areas worldwide; and determining the links between governance processes and multiple conservation outcomes.

Due to high complexity and variety of conservation practices, we will focus our analysis on conservation of forest resources only and on governance of forest PAs. To be defined as a PA, conservation governance arrangements have to: 1) have geographical limits or boundaries; 2) predominantly aim to achieve conservation benefits, but not excluding other related benefits (e.g. social benefits); 3) be designated and managed by legal gazetted means or by non-gazetted, but officially recognized NGO policies or customary laws; 4) have a body of governing rules; and 5) have a clearly identified organization or individual with a governance authority [25, 38]. We define forest PAs as “a subset of all protected areas that includes a substantial amount of forest as defined for the purposes of Forest Protected Areas. This may be the whole or a part of a protected area” ([39]:19). This IUCN’s definition excludes commercial plantations and forest managed for industrial purposes within the less strictly protected categories [39].

We aim to assess relative effectiveness of different governance regimes within forest PAs by contrasting different governance characteristics and processes on the basis of multiple measures of success^c.

There are recently quite a few studies that have estimated effectiveness of PAs (e.g. [40–42]), but they have focused solely on the tropics and only few of them assessed PAs effectiveness integrating multiple performance measures [43–45]. Apart from biodiversity conservation, PAs have various multifaceted and context-dependent objectives [43], in both, ecological and the social-economic domain. Examining PAs effectiveness in terms of biodiversity conservation only, might lead to restricted conclusions as it disregards local conflicts and resistance expressed through negative attitudes towards conservation policies and practices and anti-conservation behaviour of local stakeholders; it does not take into account institutional, economical or political changes in surrounding social-ecological systems influenced by PAs (e.g. employment opportunities or migration level) and it may reinforce a fortress conservation mentality [43–50].

This review aims at answering following primary question:

Does the effectiveness of forest protected areas differ conditionally on their type of governance?

Secondary question is:

Which characteristics of decision-making process influence the outcomes of forest protected areas?

2.1) Diversification of stakeholders’ categories (one versus multi-actor);

3.1) Nature of collaboration (formal, informal, none);

3.1) Level of collaboration (horizontal/internal, vertical/external, multilevel);

We assume that governance processes i.e. how decisions are made and implemented, influence level of conservation effectiveness, its ecological and social outcomes. Using theory of change approach, we hypothesise that: (H1) making decisions at lowest level possible, (H2) collective or multi-actor decision making, (H3) high level of proactive participation in day-to-day decision-making and (H4) multilevel collaboration among stakeholders can lead to more positive attitudinal, behavioural and ecological success of PAs and decrease negative spillover effects around them.

^a Under effective conservation we mean positive and measurable effects of conservation policies and practices on biodiversity and target ecosystems, populations, species or habitats.

^b Community conserved areas have been relatively recently internationally recognized as a PA at IUCN World Parks Congress in 2003 (Durban) and at the COP VII of CBD in 2004 (Kuala Lumpur) ([57]:1);

^c The outcome measures are adopted from Systematic Reviews by Brooks et al. [32, 34, 53] that employed set of ecological, attitudinal, behavioral and economic measures of success to estimate effectiveness of conservation intervention. However, as Pullin and colleagues [37] in their review focused mainly on social-economical analysis of terrestrial PAs, this review does not assess the economical effectiveness to avoid the potential overlap

^d A stakeholder in this study refers to those who affect and those affected i.e. both actively and passively involved individuals, groups or organizations in a PA governance (after [58]).